THE LIBRARY

OF

THE UNIVERSITY
OF CALIFORNIA

PRESENTED BY

PROF. CHARLES A. KOFOID AND
MRS. PRUDENCE W. KOFOID

•J,

THE

MICROGRAPHIC DICTIONARY.

m

FEINTED BY TAYLOR AND FRANCIS,
RED LION COURT, FLEET STREET.

k- 0?W

u\y.

PREFACE.

ON arriving at the conclusion of their labours, the Authors feel that some
apology is, in the first place, due to the Subscribers, for the extent to which
the number of these pages has been increased beyond the original estimate.
They have, however, the pleasure of stating that no complaints have been
addressed to them on this head ; but, on the contrary, strong injunctions,
when the work was somewhat advanced, to allow no considerations of
arbitrary limits to prevent equal justice being done to the subjects falling
under the later letters of the alphabet. They feel therefore that due
allowance has been made for the difficulty of calculating beforehand the
extent of a work like the present, and that the circumstance which has
chiefly led to the enlargement of the volume, namely the revision of the
articles at the latest moment before committing them to press, has been
duly taken into account.

Secondly, a few observations may be offered on the character, objects,
and uses of the work. It was stated in the Prospectus, that the ( Micro-
graphic Dictionary' was offered as an index to our knowledge of the
structure and properties of bodies revealed by the Microscope. The
Authors venture to hope that their work may possess many useful
qualities beyond those strictly implied in the above definition.

Few or none of the works hitherto published have dwelt upon the
manner in which observers might judge of the structure of objects from
the appearances presented under the Microscope. There are works
treating of the construction of the mechanical and optical parts of the
instrument, and the manner of using them, of the methods of preparing
objects for examination ] and to these are usually appended lists of objects
presenting interesting appearances. But there exists no work which will
direct the Student how to vary the methods of preparation of the objects
examined, so as to elicit their true structure.

An Introduction has been prefixed to the ' Dictionary/ affording in-
struction for the selection of a Microscope and the accessory apparatus,
explaining the manner of using these, and particularly the precautions
requisite with the less perfect but more economical foreign glasses ; and,
lastly, entering minutely into what may be called microscopical manipu-
lation and the special education of the eye.

Many valuable contributions to our knowledge of the structure or
functions of microscopic organisms are probably lost through the inability
of microscopic observers to ascertain readily the name and position in
Nature of objects which fall under their notice. It is hoped that the very

M361855

vi PREFACE.

numerous illustrations to this work will form a valuable guide in such
cases, and render the descriptions of microscopic animals and plants, of
minute structures, tissues, &c., which form the main body of the volume,
a real dictionary of objects. At the same time it is not unreasonable to
expect that much advantage may be derived from the attention that has
been paid to directing observers to subjects and disputed points on which
new information is desirable.

To the lovers of Comparative Anatomy, Physiology, or of the Natural
History of the microscopic members of the Animal and Vegetable King-
doms, the Authors have endeavoured to furnish, without departing from
the principal purpose of the work, something more than a mere descriptive
catalogue of objects, and the means of examining them. Numerous
articles on various subjects have been written with a view to enable
readers, by the help of the system adopted, and references printed in
SMALL CAPITALS, to acquire a general knowledge of particular departments
of science. Thus, taking a departure from the article ANIMAL KINGDOM
or VEGETABLE KINGDOM, the reader may proceed to the Classes and Orders
there enumerated ; under the latter will be found a general description of
these (where the microscope is much required in their investigation), fol-
lowed by a reference to the Genera, under which is given more or less
extensive information on the Species, according to the state of knowledge,
or as the subject has seemed to require. Proceeding from the article
TISSUES, in like manner, the details may be gradually collected by tracing
them through the subdivisions by means of the references. Many other
general articles are given, with such headings as the names of well-known
organs or substances, of vital or other phenomena, &c./ under which could
be conveniently collected references to a variety of miscellaneous informa-
tion scattered through the alphabetical arrangement. Those who use the
volume in this way will probably derive the greatest amount of advantage
from it; they will, it is true, most clearly perceive the deficiencies inevi-
table in a great measure to a work having such an extensive field, and at
the same time so limited a compass.

The results of a large amount of independent observation have been
consigned to these pages; and, as the bibliographical references show,
recourse has been had, as far as possible, to original sources for trustworthy
and reliable information published at home and abroad. In connexion
with this, some account may be given of the illustrations. In the Plates,
a large number of the figures are original, drawn from the objects either
by the authors or by Mr. Tuffen West ; in many cases, however, figures of
species have been designedly taken from original plates, especially when
the verbal characters were doubtful. The Authors feel bound to express
their thanks to Mr. West for the manner in which he has applied his well-
known skill and accuracy to those engravings which were entrusted to
him : many of them, indeed, appear at first sight somewhat crowded and
on a small scale ; but they will be found in most cases to display very
clearly the parts of objects on which systematic or structural characters
depend, the chief design of all the illustrations of this work. With regard

PREFACE. vii

to the engravings in the text, a portion have been selected, after compa-
rison with the objects themselves, from the excellent illustrations of the
Mikroskopische Anatomie of Kolliker. Most of the woodcuts of plants are
careful reproductions of drawings contained in original works and memoirs
by Kiitzing, Corda, Tulasne, Bischoff, Bruch and Schimper, and others,
prepared for Payer's Botanique Cryptogamique, to which, as to almost every
illustration in this volume, the magnifying power used has been added.
Had not these beautiful woodcuts been accessible to the publisher, it
would have been impossible to have provided this work so richly with
illustrations.

The authors have much pleasure in acknowledging -their obligations to the
Rev. M. J. Berkeley, Messrs. Westwood, W. S. Dallas, Sollitt, and Tuffen
West, for the loan of authentic specimens, or for information kindly afforded
on various subjects, and to Dr. William Francis, for constant advice and
assistance during the printing of the work.

JOHN WILLIAM GRIFFITH.

ARTHUR HENFREY.

London, December 1855.

PREFACE TO THE SECOND EDITION.

I REGRET that the task of writing the Preface to this Second Edition of
the 'Micrographic Dictionary' falls upon me alone, the hand of Death
having just been laid upon my distinguished and most amiable friend and
coadjutor. It will, however, be satisfactory to the reader to know that the
whole had passed under the hands of the late lamented Professor Henfrey,
and that he had taken his share in correcting for the press all but the last
three sheets.

The work has been revised throughout, and has received considerable
alterations and additions. The progress of Structural and Physiological
Botany was always assiduously watched by Professor Henfrey; and the
articles on Botanical subjects have been greatly enriched by the additions
which his extensive and accurate knowledge suggested to him. Great
improvements have also been introduced into many of the articles relating
to the Animal Kingdom, especially in the classes Insecta, Tunicata,
Polyzoa, and Foraminifera, some members of which have lately attracted
much attention. The new figures added are also numerous.

The critical reader will, it is hoped, consider that the great range of
subjects embraced, renders it impossible to do justice to all of them; and in

viii PREFACE.

many cases we have been compelled to limit our notices to little more than
the characters by which the objects are distinguishable in their respective
classes, &c. This has always been a great point in the composition of the
work — to enable the microscopic observer to discover what any object is
which may be presented to him, and by the aid of the Bibliography to refer
to more extended treatises for further details.

Our thanks are again due to those who have kindly lent us aid, especially
to Mr. Dallas for the articles Aphidae, Chalcididse, and Cynipidae; and also to
those who supported us by their friendly notices of our former labours.

J. W. G.

December 6, 1859.

PREFACE TO THE THIRD EDITION.

AT last the third Edition of the ' Micrographic Dictionary ' is completed.
But I feel that some explanation, or even apology, to the Subscribers is
requisite, considering the delay that has occurred in its issue. To ill-health
and press of prof essional engagements this is attributable. For some time,
being constantly in the hope of rapidly completing the work, I hesitated to
place it in other hands, until at last I found it essential to do so. The editing
of the work subsequently to the letter H was therefore transferred to Prof.
Duncan, whose name will form a sufficient guarantee that it has been satisfac-
torily accomplished.

In regard to the alterations made in this Third Edition, it will be noted
that nearly 100 pages of new matter have been added. The original articles
have been revised according to modern researches and views, so as to
represent, as far as space would permit, the present state of knowledge.

When I state that the Articles upon the Fungi were intrusted to the
Rev. M. J. Berkeley, and those upon the Foraminifera to Prof. Rupert Jones,
the reader will surely feel confident that they have been carefully and
faithfully elaborated. For some valuable notes on the Lichens I have to
thank the Rev. W. A. Leighton.

An important novelty in this Edition consists in the accentuation of the
names forming the headings of the articles. The classical pen of the Rev. M.
J. Berkeley has afforded aid upon this point also.

The Plates have all been newly engraved upon copper, thus rendering the
figures of the objects more sharply defined. Three new plates have been
added, and several of the original Plates have been re-arranged and improved.

J. W. G.

December 2, 1874.

PREFACE.

PREFACE TO THE FOURTH EDITION.

±N regard to the completion of the Fourth Edition of the ' Micrograph! c
Dictionary/ few remarks seem necessary. It may be stated, that the work
has been thoroughly revised. The systematic portions of the Animal and
Vegetable Kingdoms have been re-arranged according to modern views, as
far as is consistent with reference to existing standard treatises and mono-
graphs of the individual subjects. The structural portions have also been
enlarged and corrected in relation to recent observations and experiments.
The very large number of new genera, founded especially by Kent, Brady,
and Buckton, have been noticed, but in many cases somewhat briefly,
especially when the objects are rare or not likely to be easily accessible.
Had this not been done, the work would have been extended beyond the pro-
posed limits ; the references to the original descriptions have, however, always
been appended. Five new plates and some new woodcuts have been added ;
and the former plates have been altered and corrected where found necessary.
The older nomenclature of the chemical substances is retained, according
to which these are usually known and purchased. We have to thank Mr.
Rutley for his excellent plate and article on Rocks ; and Mr. Harkness, o£
the Government Excise department, for his plate of Adulterations. The
articles on the Fungi and the Foraminifera have again been revised by the
Rev. M. J. Berkeley and Professor Rupert Jones. Our thanks must also
be given to Mr. McLachlan and the Rev. Mr. Leighton for some friendly
and valuable remarks. Nor must we fail to acknowledge the assistance
afforded by our publisher, in the loan of some of his expensive works ; and
the aid derived from the use of the magnificent Library of the Royal
College of Surgeons, with the courtesy of the Librarian, Mr. Chatto. We
hope and trust that this Edition will be found as useful and interesting as
the three previous ones have surely been.

J. W. G.

December 26th, 1882.

ERRATA.

Page 51, col. 1, line 5 from bottom, for PI. 23 read PI. 30.

56, col. 1, line 14 from bottom, for Plans read Plants.

60, col. 2, line 11 from bottom, for PI. 2 read PI. 6.

68, col. 2, line 21 from top, for labrum read labium.

87, col. 1, line 15 from bottom, for Cyclostomata read Ctenostomata.

91, col. 1, line 16 from bottom, for rhitidome read rhytidome.

103, col. 2, line 6 from bottom, for muscular read molecular.

112, col. 1, line 25 from top, for inorganic read organic.

168, col. 2, line 25 from bottom, for structurs read structures.

221, col. 2, line 11 from top, for spirillium and spirillia read spirillum and spirilla.

231, col. 2, line 9 from bottom, for Cestoiden read Cestotdes.

261, col. 2, line 10 from top, for DIDIMIUM read DIDINIUM.

318, col. 1, line 27 from top, for introcellular read intracellular.

495, col. 1, line 29 from top, for ^yVzr read 77&ro.

525, col. 1, line 8 from bottom, for always read also.

577, col. 2, line 16 from bottom, for PAEAPHY'SES read PAKAPH'YSES.

621, col. 1, line 12 from bottom, for Actinaria read Actinozoa.

661, col. 2, line 20 from top, for pearlite read perlite.

664, col. 1, lines 22, 25, and_26 from bottom, for Noseau read Nosean.

675, col. 1, line 5 from bottom, for Symbistes read Symbiotes.

682, col. 1, line 12 from top, for Spirillum read Vibrio ; and for inflexible read flexible.

INTBODITCTION.

I.— USE OF THE MICROSCOPE AND EXAMINATION OF
MICROSCOPIC OBJECTS.

BEFORE entering upon the special consideration of the Microscope, of which the Intro-
duction treats, it may be well to make a few remarks upon the general use of the instru-
ment in the examination of minute objects.

The Microscope will either be used as a means of affording amusement, or with a view
to scientific research. In the former light, no philosophical instrument can compete with
it, in regard to the great variety, the beauty, and the wonderful phenomena of structure
which the minute objects it enables us to examine display, even independently of the con-
sideration of the functions and uses of their several parts. In this light also, the inves-
tigation of the comparative structures and properties of various bodies or substances
used in daily life as articles of food, dress, &c. will form subjects of intense interest to
any one who may be possessed of the instrument. The mysterious phenomena of growth,
reproduction, and crystallization may also be watched throughout their progress, j ust as
we can see the effects of parts of machinery with the naked eye. But while the sense of
sight is thus gratified, the mind will not be unoccupied ; for every fresh appearance will
impress a new fact ; so that here we have both amusement and instruction combined.

It is, however, to the use of the Microscope as a means of scientific research that our
remarks are most necessary ; for in this great care and consideration are required, and
these are very apt to be neglected by those who are unaccustomed to employ this valuable
instrument.

The Microscope as a means of investigation might perhaps be thus defined : the micro-
scope is an optical instrument constructed in order to enable us to investigate the characters
and properties of those objects which we are unable to study with the unassisted eye, on
account of their minute size.

The use of the Microscope will resolve itself into either that of proving the structure of
a known object, or determining that of a new one ; and in thus applying it, exactly the
same precautions must be adopted, and just the same course pursued, as if the object under

xii INTRODUCTION.

examination were distinctly visible to the unaided eye. The above formal definition of
the true use of this valuable instrument is requisite, because it is very frequently used
simply as a means of vie winy minute objects, and judging of their nature from the mere
inspection of them under the conditions in which they naturally or accidentally occur.
Such a procedure, the most casual observer must be well aware, is never trusted alone in
the examination of objects visible to the naked eye, being almost sure to lead to erroneous
conclusions. Consider the common course pursued in the macroscopical examination, or
that with the unaided sight, of a body for the first time presented to our notice ! The
first point is the examination of its general appearance and colour ; the relative position of
the eye of the observer and the object is then changed, so that an idea of its solidity may
be obtained j its weight is next perhaps determined by taking it in the hand ; it is pre-
sented to the light in various ways, in order to judge of its transparency, and of the optical
properties of its surface. If the object be at a distance, its size is judged of by comparing
its apparent size with that of adjacent bodies, whose dimensions are approximately known ;
and its luminousness is also taken into consideration, it being known generally that the
nearer bodies of the same size are to us, the more luminous they appear. The observer
then is either satisfied with the conclusions drawn from reasoning upon the results thus
obtained, or he makes besides a chemical examination.

Again, care should be taken to avoid forming an opinion- upon the normal or abnormal
state of an organic structure, without a previous knowledge of the natural structure of
organic tissues. We therefore recommend the student, before he thinks of recording his
observations, to begin by testing the structure of any objects which may come in his wa}',
or that of the TEST-OBJECTS which we have described, according to the rules laid down
in the second part of this Introduction.

It may be remarked for those who have but small means at their command, and who
are unable to procure a first-rate English microscope, that perhaps very many of the facts
elicited by the use of this instrument have been determined by our continental neighbours
with far less perfect instruments, who have made up for the imperfections of their instru-
ments by extreme patience, care, and repeated observation; which can be done to an
extent that would scarcely have been anticipated.

We have alluded to these sources of error merely for the purpose of warning future
observers, and impressing upon them the importance of making themselves acquainted
with the difficulties attendant upon microscopic investigations, and with the best means of
overcoming them. In fact, it may be briefly stated that the object of the present work is
to guide the microscopist in his researches, to give him a notion of the manner of making
these researches, also some account of the characters, microscopic structure, and properties
of objects in general, and to show how he may most easily arrive at satisfactory results.

But there are difficulties inherently connected with the examination of microscopic
objects, which are not encountered when objects are examined with the naked eye. One
of these is that, with the ordinary microscope objects are only viewed with one eye ; hence
we lose the direct power of distinguishing solidity, &c., and are compelled to resort to
indirect means for these purposes. This difficulty is to some extent overcome bv the con-
struction of binocular microscopes. Again, the ordinary objects around us are also usually
viewed by reflected light, whilst with the microscope they are mostly viewed by trans-
mitted light, and we are consequently much less practised in judging from the appearances
of objects thus illuminated, and are therefore liable to err,

INTRODUCTION. xiii

Another, but a less important difficulty in microscopic investigations, or at least mani-
pulations, consists in the image of the objects being inverted. Erecting eyepieces, as they
are called, will obviate this difficulty ; but as they are expensive, and interfere with, the
distinctness of the images of the objects, and as the difficulty is to a great extent got over
by practice, they are rarely used.

Another very serious source of error lies in the tendency to reason from analogy as to
the structure or nature of a body viewed under the microscope. Any one who pursues
this course has his mind prejudiced by preconceived notions, and becomes in fact no
observer at all.

It need, moreover, be merely remarked that the ordinary appearance of objects to the
naked eye depends in all cases upon a molecular structure, which is generally microscopic,
the ordinary appearance being the optical result or expression of this structure ; and since
totally dissimilar microscopic structures may present similar appearances to the unaided
eye, judgment as to the nature of the former founded upon the latter can be of but little
value. The reader will remember that the common capability of distinguishing objects or
structures by their appearance has been derived, so to speak, from practice and experience
of effects ; and when we bear in mind that the experience and practice in the study of the
causes are attainable, the superiority of the latter must be evident.

Next to the improvement effected in the optical construction of the microscope during
the last few years, must be placed that of the method of investigation. Formerly almost
all microscopic bodies possessing different forms and appearances were considered distinct
beings, and were named accordingly. By the present method, prolonged observation is
adopted to follow the changes which the individual bodies undergo ; whence it has resulted
that numbers of them have been found to be simply different stages of each other. Thus
a large amount of useless nomenclature and confusion is being removed from the domain
of the microscopic world.

Above all, however, it must never be forgotten that microscopic investigations require
more time and patience than perhaps any others, even in regard to the determination of
simple points of structure and qualitative composition. In fact, notwithstanding the innu-
merable observations made upon the more minute objects, such as the scales of insects, the
markings on the valves of the Diatomaceae, the fibrillre of muscular fibre, &c., such dif-
ferences of opinion are still entertained, that it can by no means be asserted that the
structure of these bodies is positively known.

The time has passed at which the value of microscopic research could be called in
question. The wonderful insight gained by its use into the structure and functions of the
various organic beings belonging to the Animal and Vegetable Kingdoms, the aid it has
afforded Geology, the so-called practical applications it has permitted in improving the
arts, in detecting adulterations, and in defeating crime, moreover the almost positive
certainty we have obtained that it is capable of displaying all the real structure which
bodies possess, save that of their ultimate niolecularity, which will probably always be
hidden from us, are sufficient to deprive this question of any interest.

Lastly, if it were required to prove design in the creation, this could not be more easily
effected than by the examination of the structure of microscopic organisms.

We have expressed our intention of not entering upon a description of the microscope
as an optical instrument, because it would have been requisite to tread widely the field of
general optics, which our space does not permit. We would therefore advise those who

xiv INTRODUCTION.

wish to become acquainted with the microscope as an optical instrument, first to study the
general laws of optics, which may "be done through the medium of any of the works or
treatises on Natural Philosophy — as the article ' Optics' by Ilerschel in the Encycl.
Metropolitan, Brewster's 'Optics,' Lloyd's 'Manual,' Deschanel's 'Optique,' Verdet's
1 Lecons d'Optique Physique,' Nageli and Schwendener's ' Mikroskop/ ' Ganot's t Physique '
(transl. by Atkinson), or Rodwell's ' Dictionary of Science.' Perhaps the second work is the
best for the general reader ; it is an old standard work, but greatly behindhand in regard
to the use of the microscope. They may then proceed to the application of these laws to
the various optical parts of the microscope. This will be found in the works enumerated
at the end of the Introduction.

We must not, however, omit a notice of the principles which should guide in the selec-
tion of a microscope and the accessory apparatus, because a large number of microscopes
are at the present day sold, frequently at no mean cost, which, although well calculated
to afford amusement, are utterly valueless for the purpose of scientific investigation. To
those to whom money is no consideration, we may recommend with safety, as the best
which can possibly be procured, such as are manufactured by Ross, Smith and Beck, or
Powell, of London. These makers have a thorough knowledge of the instrument, and a
reputation at stake ; hence there is little occasion to test their instruments. But it may
happen that a person may not wish to expend so much money as the purchase of these
instruments requires, may wish to procure a foreign instrument (and these are cheaper),
or may meet with one second-hand. A word or two may then be of service in guiding
them in their choice ; for a microscope may look very well and very handsome, yet be
worth but little. It must, however, be borne in mind that there is much room for opinion
in these matters j for according to what any one has been accustomed to, or according to
prejudice arising from what he may have heard a supposed authority say, so will an
instrument or a piece of apparatus be regarded as requisite or of importance, or not.
Our statements rest upon our own experience in the long-continued use of the instrument,
and as such they must be taken.

First, it may be remarked that the microscope is usually regarded as composed of the
stand, body, stage, eye-pieces, and object-glasses : and the object-glasses are generally sold
separately ; for by means of an " adapter " they can be applied to any microscope.

In regard then to the stand, body, £c. : the stand should be firm, and so heavy and it*
feet so arranged, that the instrument cannot be easily overturned.

The body, whether the microscope has one body only, or is binocular, should be about
8 or 10 inches in length j in many of the foreign and cheap English instruments the body
is short, and the eyepieces are adapted accordingly j but this adaptation is decidedly
objectionable.

Whether the microscope shall be binocular or not must be a matter of opinion. In the
binocular microscopes there are two bodies and two eye-pieces, the rays of light just above
the object-glass being divided by a refracting prism into two portions, one of which passes
through each tube; in this way the stereoscopic view of objects is obtained. The
binocular arrangement is an additional expense ; it can be added to any microscope j but
any binocular microscope can be used as a single-bodied instrument (See BINOCULAR).

The microscope should be so constructed that the body can be inclined at any angle
desired, so that the observer may examine objects while sitting. Many persons, however,
prefer to use the microscope with the body placed perpendicularly; and when chemical

STAND—STAGE. xv

reagents are to be applied this position is essential ; but when long-continued examination
of an object is required, it becomes very painful and fatiguing to keep the head in the
position which the perpendicular position of the body requires. Moreover, as in a micro-
scope with the joint or arrangement by which the body can be inclined the body can
always be placed perpendicularly, the joint is decidedly advantageous. Again, it is almost
essential when the camera lucida is used. A brass pin or some similar contrivance should
be placed near the joint so as to check the motion of the body of the microscope when it
reaches the horizontal position ; no microscope should be without this.

In most microscopes a tube sliding within the body and carrying the eyepiece forms a
u draw-tube." By drawing this out the magnifying power becomes enlarged without
changing the eyepiece ; it is very useful with the erector or erecting-glass (p. xxii) ; and
serves occasionally to produce slight corrections for variations in the thickness of the
covers, with immersion-lenses.

The microscope should have a coarse rack-and-pinion movement or quick motion
for adjusting the focus of the lower powers or object-glasses; and when used with an
object-glass of about half an inch focus, the image of the object examined whilst coming-
in and going out of focus, must not appear to move from one side to the other of the field
when the body is raised or depressed by the coarse movement. Also when the milled head
of the coarse movement is rotated, the motion should feel smooth, not irregular, uneven,
or jerking. In some foreign microscopes, the effect of the coarse rack-and-pinion move-
ment is replaced by the sliding of one tube within the other, the body consisting of two
tubes working after the manner of those of a telescope. This arrangement is very objec-
tionable, although used by some very good observers, who probably have more tact than
most people, and who do not use such high powers as they ought ; for when the highest
powers are used it is perfectly intolerable. The objection is somewhat overcome in some
microscopes by the existence of a fine movement ; but we regard the rack-and-pinion
coarse adjustment as essential.

A Jine movement or sloiv motion is indispensable j for with the higher powers (one
eighth and upwards) it is impossible to adjust the focus without it. When the finger
or fingers are applied to this in its use, no apparent motion of the object must take place ;
should this occur, the movement is worthless, unless, at all events, it is very slight, and
this when tested with the high powers.

When the milled head of the fine movement is turned backward and forward, as in use,
the motion should be perfectly even, and should be produced very easily, with slight
pressure only of the finger or fingers ; moreover no difference should be distinguishable
between the two directions in which it is turned, but it should move with equal ease in
both.

The Jield or luminous disk on which the objects viewed through the microscope are
apparently delineated, should have its marginal line clear and black. If this line appear
coloured, the eyepiece is not as it should be.

The stage should not be too small, (say less than 3 inches in diameter). To the best
instruments a moveable stage is adapted ; but whether this is essential or not is considered
a matter of opinion. Undoubtedly with low powers the moveable stage may be dispensed
with, and is not often used ; but with the higher powers its absence is felt greatly, and we
should say that it is essentially necessary. In most of the English microscopes, whether
provided with a moveable stage or not, there is a " sliding piece " for producing the back-

xvi INTRODUCTION.

ward and forward motion of an object, the lateral motion being effected by direct applica-
tion of the fingers. If the body of the microscope is to be used in the inclined position
the sliding piece or a moveable stage becomes essential.

If the moveable stage be present, the " milled heads " should be pretty large, so as to
be readily grasped; and a flat object should remain in focus whilst traversing the field by
the movement of the stage. The stage should also be very thin.

The mirror should have one plane or flat face, and another concave. It should not be
too small j and its centre should coincide with the axis of the body of the microscope. A
double arm enables the mirror to be brought more considerably to either side, so as to throw
more oblique light upon an object.

So long as the above conditions are fulfilled, the general form and arrangement of the stand
and its parts are of little consequence. It must also be remembered that the complication and
accuracy of the apparatus required will vary according to the kind of investigations pursued-
Thus the structure of the various tissues of animals, and that of most plants, can be satisfac-
torily studied with apparatus which is totally insufficient to display the structure of certain of
the more minute and difficult objects ; but, on the other hand, it follows that if a peculiar
structure can be shown to exist in any kind of objects by a complicated apparatus, which
cannot be demonstrated by a more simple or less perfect apparatus, the study of the struc-
ture of any object not previously examined must always be attended with uncertainty so
long as it has not been tested by the more perfect kind of apparatus, — provided the micro-
scopist has not acquired the art of replacing the imperfection of his apparatus by superior
tact and management, which can be done to a great extent.

Object-glasses, often called Objectives. — These form the most important portions of the
microscope. The value of the object-glasses depends mainly upon their freedom from
chromatic and spherical aberration, and upon the magnitude of their angular aperture. The
freedom from the former renders them good in defining power, «. e. in exhibiting clearly the
margins or outlines of objects or structures; whilst large angular aperture renders them
capable of penetration, or of resolving the more delicate markings upon the surface of
objects. But there are two kinds of penetrating power, as we shall show in the article
"TEST-OBJECTS," where we have entered more fully upon this subject.

As in the case of the stand &c. of microscopes, so in regard to the object-glasses ; the
best are made in this country, and can be obtained of first-rate quality of the three makers
above-mentioned. But the French and German object-glasses have been very greatly im-
proved in late years, and are now largely used, especially the immersion-glasses as they are
called (OBJECT-GLASSES) ; and some of these resolve perfectly most of the difficult valves
of the Diatomaceso ; and they are cheaper than the English glasses. The names of Hart-
nack, Zeiss, and Gundlach are well known as those of excellent makers. Some of the
American object-glasses also, which are but little known in this country, must stand in the
first rank in regard to excellence in defining and especially penetrating power. When a
glass of unknown value, however, presents itself, it should be tried upon the test-objects.

The defining power maybe tested by the examination of the objects figured in Plate 1.
figs. 1 to 4.

The outlines or margins of these objects must appear black, well defined, and perfectly
free from colour, not misty, nor red or green j they should retain this appearance when the
higher eyepieces are used, of course some allowance being made in regard to the sharpness
of outline, which will appear slightly broader and less defined, but nowise interfering1

OBJECT-GLASSES. xvii

with, the distinctness of the image of the object. The various parts of an object lying in
the same plane, as a transverse section of whalebone, should also be visible at the same
focus ; the lines upon a micrometer used as a slide will also serve to test this point. It is not,
however, of very great importance, especially with high powers ; but it is a character of a
superior object-glass.

If the definition of the glass be good, the field flat, and the power adequately high, it
will also exhibit the structure of the objects in Plate 1. figs. 5, 6, 10, 12, and 13 clearly and
distinctly ; it is then of sufficiently good quality for nearly all the purposes required in the
investigation of animal and vegetable structures.

The exhibition of the objects illustrated by Plate 1. figs. G, 7, 8, 9, 10, 11, 12, and 13
requires the first kind of penetrating power, but it does not require large angular aperture.
The second kind of penetration, however, requires, above all, large angular aperture, inde-
pendently of any other superiority; i. e. a glass may be perfectly corrected as to defining
power, and exhibit the above objects well, yet when the valve of a Pleurosiyma is sub-
jected to it the markings cannot be distinguished without particular appliances, which
produce the same effect as an increase of angular aperture in the object-glass. As this
property is therefore principally dependent uponr the angular aperture, this should be de-
termined by direct measurement ; the method of doing which is described under the article
"ANGULAR APERTURE," in which also is contained a list of the various apertures of the
best glasses, so that the approximation in the case of any glass to these magnitudes will
afford an indication of its quality. It must be observed that increase of angular aperture
in an object-glass involves an increase in price.

The following remarks may perhaps assist in guiding the judgment in regard to the
selection of an object-glass : —

Large angular aperture is of less importance in the case of a low than of a high power.

Large angular aperture is neither requisite nor advantageous in physiological and medical
investigations in general.

Whether a glass of larger aperture will exhibit any further structure than one of less
aperture has already done, can nearly always be predicted from other means.

Object-glasses of high power and large angular aperture require to be brought very
close to the objects viewed, which is a great disadvantage, rendering them useless for
general investigations.

In regard to objects requiring large angular aperture for exhibiting their structure, much
depends upon the management of the light : so that a glass may fail in exhibiting certain
parts of structure in the hands of one of but little experience, whilst in the hands of another
it may show them distinctly. Hence the direct measurement of the angle is best, to deter-
mine what a glass is capable of exhibiting when properly used.

The student may perhaps find himself perplexed by the conflicting statements made by
different renowned observers in respect to object-glasses. The illustrious Schleiden said
that only a magnifying power of about 500 diameters is useful for scientific purposes, that
witli our present microscopes we may see whatever we like with a power of 3000, and that
only the amplification of an object to the extent of 280 or 300 diameters is produced by the
object-glass, all beyond this being effected by the eyepieces with an almost total ^oss of
light. These statements were perhaps formerly true ; but they do not apply to the modern
object-glasses. The highest modern object-glasses will show minute objects with a power
of from GOO to 2500 diameters with the lowest eyepiece, as clearly and well defined as the

xviii INTRODUCTION.

ordinary glasses of 1-inch focus will show larger objects; hence enormous improvements
have latterly been made in object-glasses,— the increased magnifying power being produced
by the object-glasses and not by the eyepieces, by which means the visible images are
rendered most distinct and trustworthy ; for the object-glass alone produces the structural
image of the object, which is magnified by the eyepiece, but the latter elicits no further
structures.

According to modern views, about 800 diameters is the magnifying power of the object-
glass which will resolve all visible structure. High eyepieces, even to 50,000 diameters,
will magnify the images, but will not elicit further structures.

For ordinary useful purposes, the £ or § inch and the £inch object-glasses, with the first
and third eyepieces, will suffice. With the draw-tube and the third eyepiece, the \ will
magnify 900 diameters, which is sufficient for most ordinary investigations.

Recent investigators with very high powers, especially with immersion-lenses, have
brought to light new structures hitherto overlooked ; we need merely mention the muscle-
rods (Plate 22. fig. 36 c), the sperniatozoal membrane (Plate 50. fig. 25), and the ciliimi
of Bacterium (Plate 1. figs. 19, 20), &c; but all the lenses made by the best makers, both
English and foreign, are provided with an immersion-front. These structures, which are
very difficult to exhibit with the older microscopes and object-glasses, show the impor-
tance of using very high powers, especially the TV or ^ inch.

Diaphragm. — Most microscopes are provided with a diaphragm. It consists of a circular
blackened revolving plate, placed beneath the stage and having a series of circular apertured
of different sizes, each of which can be brought successively opposite to the axis of the
body of the microscope. It serves to regulate the quantity of light in examining trans-
parent objects; it also reduces the angle of the cone of the reflected rays. It is seldom,
however, used, nearly the same effect being produced by the two different surfaces of the
mirror.

Revolving Staye-plate. — One of the plates of which the inoveable stage is composed is so
constructed as to revolve in the same plane upon its axis, whereby an object may also be made
to revolve in the same manner. This apparatus, however, has some disadvantages in the
older microscopes ; for it renders the stage heavy and increases its depth ; ami the desired
effect may easily be produced by rotating the slide with the fingers ; moreover it is exceed-
ingly difficult to place the object in the centre of rotation. It is however, provided in the
best modern instruments, and is by many considered of importance ; the old thickness of
stage has also been avoided.

Spring Clamping-piece is intended to fix the slide upon the stage. It is of little use pro-
vided the slides are of the proper length, which we have given; if they are longer, the clamp
will prevent the accidental displacement of an object in changing the power, &c. It server,
however, to fix the slide in viewing objects by oblique light, when the slide projects beyond
the edge of the stage, and to prevent its tilting over.

Forceps are essential for holding opaque objects, such as insects, and viewing them in
different positions ; to allow of which, the handle of the forceps is made capable of
revolving.

The Disk-revolver (Beck) is a very useful apparatus. It serves to bring into view all parts
of an opaque object, but that which is attached to the disk.

Dark Wells are metallic cups of various sizes, blackened inside, and serving to prevent the
.reflection of light upon opake objects from below. They are supported in a holder,

ACHEOMATIC CONDEXSEK. xix

moveable in an arm which is inserted into some part of the stand of the microscope. Their
purpose is equally well effected by a slide beneath which a piece of black velvet has been
fastened by marine glue.

Achromatic Condenser. — This consists of an achromatic object-glass, or set of lenses, placed
in an inverted position beneath the stage, usually in a "secondary" stage, and moveable
in all directions in its own plane and in the direction of its axis. It serves to condense the
light reflected by the mirror to a focus upon the object, and to exclude all extraneous light.
It is essential in examining minute objects with high powers ; in fact, the structure of many
objects cannot be made out without it. In the excellent Gillett's condenser, a rotating dia-
phragm is placed behind the back glass of the combination forming the condensing object-
glass, perforated with a series of apertures of various sizes, some of them being circular,
whilst others are annular — the former diminishing or increasing the cone or pencil of rays
reflected from the mirror by excluding the lateral rays, the latter admitting only the lateral
rays, the central ones being intercepted by the portion of the diaphragm within the ring,
so that the angular inclination of the transmitted rays may be increased or diminished at
will. In its most improved form it consists of two concentric revolving diaphragms, with
central stops, by which the relative sizes of the apertures and stops can be varied ; and its
angle of aperture is 170° (Powell). In the latest form, it represents a " swinging " substage.
The markings upon many of the Diatomacese can only be made out when examined by
oblique light, as procured by intercepting the central rays, which effect is produced by this
modified achromatic condenser. The same effect may be produced to some extent in one
of the achromatic condensers of the old form, provided the compound lenses of which the
object-glass in the condenser consists are separable, by pasting or temporarily placing a
circular disk or " stop " of black paper exactly upon the centre of the plane face of the
innermost combination. The diameter of the disk should amount to about two thirds of
that of the surface of the combination to which it is applied. The combinations are then
fitted together as they were at first. This stop intercepts the central rays, thus diminishing
the amount of light transmitted; but this difficulty is easily got over. When the
achromatic condenser is used, the flat surface of the mirror should form the reflecting
surface, and care skould also be taken that the axis of the condenser coincides with that
of the object-glass. To ensure this, a small cap of brass having a minute circular aperture
in its centre should be fitted to the lower part of the tube in which the condensing lenses
are situated. When the object-glass is properly adjusted with regard to the condensing
lenses, the field of the microscope will appear black, excepting at a minute luminous
spot. This spot must be made to occupy the centre of the field by moving the laterally
adjusting screws of the condenser, or the body of the microscope j as soon as this has
been effected, the brass cap must be removed. Or Ross's centering-glass may be used : this
consists of a tubular eyepiece cap, in which are two plano-convex lenses so adjusted that
the image of the aperture in the object-glass, and the images of the apertures of the lenses
and diaphragms of the condenser, may all be seen in focus at the same time, and their
centricity or excentricity determined.

The focus of the condenser must be made to fall upon the object, which can be effected
by raising or depressing the condenser until the window-bars by day, or the lamp-flame
by night, are brought into focus ; but if the image of these interferes with the view of an
object, the condenser must be lowered to displace them.

The paper-stop may be very advantageously replaced by a blackened metallic stop placed

xx INTRODUCTION.

behind the first pair of lenses of the condenser, and screwed into the top of the condenser
in the place of the ordinary diaphragm. Neither of these kinds of stop equals in conve-
nience the improved Gillett's condenser, because with the latter the number of rays
transmitted or intercepted, and the degree of their obliquity, can be varied by the simple
rotation of the diaphragms. The spot-lens is also used for the same purpose. This consists
of a very convex plano-convex lens, placed beneath the stage, the central rays being inter-
cepted by a stop.

The central stop is generally used when objects are examined with the higher powers.
The power used in the condenser will vary greatly according to the kind of object under
examination. If a considerable amount of light be required without obliquity of the rays,
the condensing power should be lower than that of the object-glass. If great obliquity
of the rays bo required, the higher the power of the condensing lenses, and the larger
their angular aperture, the better. When the achromatic condenser is suitably arranged
in regard to centering, and the condensing object-glass or set of lenses is properly selected
and adjusted, the structure of minute objects is displayed in a manner with which those
who regard the condenser as useless must be utterly unacquainted. Many very delicate
objects are rendered most distinct by using the smallest aperture in the diaphragm of the
condenser, so that the admitted rays are almost parallel. But this requires a very
powerful light.

"Extra Eyepieces. — Always one, and mostly two or more eyepieces, or oculars as they
are sometimes called, are obtained with the microscope when purchased : but the highest
eyepiece which is made should always be procured j for although high eyepieces are so
far objectionable that they magnify the imperfections of the image formed by the
object-glass as well as the image itself, yet they frequently render parts of structure
distinct which are perhaps only just perceptible with a lower eyepiece. Kellner's ortho-
scopic eyepiece, in which the lower lens is doubly convex, gives a very large and flat
field.

Polarizing Apparatus or Polariscope. — This usually consists either of two plates of
tourmaline, or of two Nicol's prisms. The latter are generally used, and are preferable
on account of their freedom from colour. They are composed each of two half-rhombs of
calcareous spar cemented together so as transmit only one image. The prisms should
appear perfectly clear and colourless, and free from scratches and veins ; and when, on
holding them to a light, the uppermost is rotated so as to occupy a particular position
with regard to the other, no light should be transmitted through them.

The polarizing apparatus is useful in bringing to light certain peculiarities of structure
which cannot be detected in any other way ; and is particularly useful in the study of
minerals (RocKs). A substitute may be made of two crystals of the iodo-disulphate of
quinine, dried upon and cemented to circles of thin glass. In use, one is placed beneath
the object, and the other on the top of the eyepiece.

Spectroscope. — The spectroscope, as applied to the microscope, is a somewhat expensive
apparatus, and requires great practice in its application. It is, however, most important
in many investigations. See SPECTROSCOPE.

Side Condenser. — This consists of a large doubly convex or plano-convex lens, or " bull's-
eye," of short focus, 2 or 3 inches, mounted upon a brass arm, which slides up and down a
rod placed perpendicularly in a stand. The arm should be capable of being lengthened, and
the stand should be so broad and heavy that there need be no fear of its being overturned.

AMICI'S PRISM, ETC, xxi

Its use is to condense the light upon opaque objects, When used, it is placed between the
object lying upon the slide under the microscope and the lamp or other source of light,
which should be about 6 or 7 inches from the object, the plane surface of the lens being at
right angles to the direction of the rays of light, and next the object ; and the lens must be
brought so close to the object that the focus falls upon the latter. Sometimes a " small
condensing lens " is used to concentrate the light already transmitted through the large
condenser : this is usually fixed to some part of the microscope. A doubly convex lens of
much longer focus than the bull's-eye lens, about 7 or 8 inches, will be found very useful
for condensing the light upon the mirror when the achromatic condenser, stops, &c. are
used with the highest powers. The arm of the bull's-eye lens may be adapted to hold
either or both of the lenses.

AmicPs prism is sometimes useful for throwing very oblique light through a transparent
object. It consists of a flattened-triangular glass prism, the two narrower sides of which
are convex. The third and broadest side forms the reflecting surface. The prism may be
attached to a separate stand, or to the secondary stage. It is sometimes mounted on a
pillar placed beneath a large brass slide, perforated in the centre. A triangular prism
mounted in either of these ways forms a Reade's prism, and is used in the same manner.
Arnici's prism exerts a condensing as well as reflecting action.

LieberMhn. — Some opaque objects may be well illuminated by a lieberkiihn or silver
cup ; by which the light, first reflected by the mirror upon the concave surface of the
cup, is afterwards reflected upon the object. It is not adapted for higher powers than
the 5 inch.

Wenham1 s Parabolic Reflector. — The discovery of the importance of excluding the
central rays of light, and using a central stop for this purpose, is due to F. H. Wenham,
who invented an apparatus in which this principle is taken advantage of. It consists
of a brass tube fitted beneath the stage in the place of the ordinary achromatic condenser,
terminated above by a hollow truncated cone the perpendicular section of which forms a
parabola, with an internal polished silver reflecting surface. At the base of the parabola
is placed a disk of thin glass, in the centre of which is cemented a dark well. In use, the
central rays are stopped by the dark well, whilst the lateral rays, passing up the tube,
impinge upon the parabolic surface, from which they are reflected upon the lower surface
of the object. This apparatus, as modified by Shadbolt, is constructed of a solid cylinder
of glass terminating above in a cone the surface of which has the form of a parabola and
replaces the silver reflecting surface — and is the form now generally used. In objects
viewed under this or any other form of black-ground illumination, the light reaching the
eye is all reflected from certain suitably inclined surfaces of the object. This may be
proved by placing a polarizer beneath the reflector, selecting as the object some small
strongly polarizing crystal?. On applying the analyzer, no colour will be seen, showing
that the light has not passed through the object. Hence care must be taken in drawing
conclusions from the appearances.

Brooke's Reflecting Apparatus. — The purpose of this is to illuminate objects by reflected
light, so that they can be examined with the highest power. It consists of two parts ; the
first is essentially the same as the apparatus proposed by Wenham. The second consists
of a small, flat, circular metallic mirror (a flat lieberkiihn), perforated to admit the lower
end of the object-glass, upon which it slides, and so arranged that the reflecting surface is
in the same plane as the lower surface of the object-glass. When in use, the light is

xxii INTRODUCTION.

reflected by the parabolic surface upon the plane reflector, and thence upon the upper
surface of the object. This apparatus has lately given place to the next-mentioned.

JBeck'ts Opaque Illuminator, which is a valuable piece of apparatus, is constructed thus : —
A short screw-tube, or adapter, with an aperture in one side> is fitted between the end of
the body and the top of the object-glass. Within the tube is a circle of thin glass, set
obliquely, so that the light entering the side aperture is reflected by the circle upon the
surface of the object, and passes upwards to the eyepiece. This may be used with the
fa to T^-inch immersion-lenses; and with it the hexagonal markings of Plenrosiyma
anyulatum are distinctly seen, and the lines of fracture running through the areoles
(Moorehouse).

Tolks's Illuminator consists of a prism inserted in the side of the object-glass, between
the front and middle combinations, so reflecting the light entering by a side aperture upon
the object. See also ILLUMINATION.

A number of points in regard to the colour of objects, distinction of pigment-granules
from minute air-bubbles, &c. may be decided by these pieces of apparatus. In questions
of elevations or depressions of surface, conclusions must be based upon the analysis of the
formation and arrangement of the shadows, and not upon the general appearance, because
it is well known that objects, or parts of them, usually appear larger and more prominent
in proportion to the amount of light reflected by them to the eye. Hence, for instance,
little depressions, which are in fact extensions of surface, by reflecting more light than the
surrounding flat or nearly flat surfaces, would appear very brilliant and luminous, and thus
resemble elevations.

Camera Lucida, and steel di^k or Mirror of Scunnering. — One of these is requisite for
drawing from the microscope. The camera lucida resembles that commonly used in
sketching landscapes &c., but is provided with a fitting adapting it to the eyepiece. The
mirror of Soniniering is a plane mirror of polished steel, less in diameter than the pupil of
the eye, supported opposite the focus of the eyepiece by a small steel arm attached to a
split ring which grasps the eyepiece by a spring-action. There is one disadvantage
attending the eyepiece of Sommeriug, viz. that it inverts the image of objects, which the
camera does not. When either of these is used, the body of the microscope must be placed
horizontally, and the axis of vision be directed perpendicularly ; the image of the object
will then be seen upon the table, and may be traced with a pencil. In using the camera,
it must be remembered that the size of the object will appear greater as the distance
between the eyepiece and the table is increased ; hence it is best always to place the
microscope in one and the same position when about to use it for drawing, so that the
extent to which the objects are magnified by the same power may always be the same.
The pin mentioned at page xv is invaluable for this purpose. By placing a inicroineter-
slide upon the stage, and comparing the magnified image of the divisions with those on a
known measure, such as a graduated rule, the magnifying power can always be checked,
and any error arising from varied distance determined.

Beale's neutral-tint glass reflector is often used as a camera, and is inexpensive.

In using either the camera or the mirror of Sb'mmering, the eye must be kept exactly in
one position ; otherwise the image of the object will move. Also the field and the paper
must be illuminated to nearly the same extent. One of the screens mentioned at page xxviii
is very useful for excluding extraneous light.

Erecting-ylms (Lister's). This consists of a brass tube, furnished with a meniscus at

LIVE-BOX AND GBOWING-SLIDE, ETC, xxiii

the upper and a plano-convex lens at the lower end. It is screwed into the diaphragm of
the body of the microscope, or that of the draw-tube. It erects the images of objects, and
serves, with a low object-glass, to reduce the magnifying power at pleasure, and to
facilitate dissection under the microscope.

Live-Box and Growing-Slide. — The live-box is an apparatus in which portions of liquid
containing infusoria and other small animals or plants can be confined so as to prevent
evaporation and allow of their being watched in a living state.

A better apparatus, however, for this purpose is my growing-slide. This consists of a
piece of stout plate-glass, 5 inches long and about 2 wide. A circular aperture, of about
the diameter of a test-tube, is made near one end oi it. A little glass cup, formed of a
portion of a test-tube cut off three fourths of an inch from the closed end, and slightly less
in diameter than the aperture, is then fitted into the latter, either by pieces of cork, or
by a rim consisting of a glass ring forming a neck to the cup, or in any other way. The
cup should project about one fourth above the surface of the slide ; and at one portion of
its margin a little groove should be ground, in which two or three threads of a lamp-wick
can be placed. The cup should be covered with a circular plate of thin glass, larger than
its mouth, and prevented from falling off by a disk of cork fitting the mouth and fastened
to the plate by marine glue ; or the cup may be closed with a common cork, the only ob-
jection to this being that the mouth of the cup is apt to split. The manner in which the
slide is used is this : — Supposing it is wished to follow the changes undergone by some
minute alga or infusorium which has been detected in a drop of liquid, it is placed upon a
slide and covered with thin glass ; the slide is then placed upon the growing-slide in such
manner that the longer dimensions of the two are in the same direction ; a little ledge
consisting of a strip of glass fastened by marine glue to the growTing-slide will serve to rest
the slide against, and prevent its becoming displaced. Distilled water, mixed with a small
proportion of the water in which the organism was living before being transferred to the
slide, is next put into the cup, and a few threads of lamp-wick cotton, thoroughly moistened
with distilled water, are then so placed that one end is immersed in the cup whilst the
other is brought into contact with the edge of the liquid in which the object is immersed.
Thus, as the water evaporates from beneath the thin glass, the threads will afford a con-
tinuous supply, and the threads will not become dry until the whole of the liquid in the
cup has become absorbed by them and evaporated. In 'this way we obtain the requisite
conditions for the continued growth of aquatic organisms. Care must be taken, however,
that the thin glass presses but slightly upon the object, and that the threads come as little
as possible into contact with the portions of the slide lying between the cup and the thin
glass. If the thin glass cover to the cup fit tightly, and the thread be passed through the
notch in the cup, no loss will take place by the direct evaporation of the liquid in the cup.
In many cases a modification of this slide is -arranged so that organisms can be kept
in a warm liquid; this is very useful in examining amoeboid movements of the blood-
corpuscles, leucocytes, &c. Several varieties of this have been devised (GROWING-SLIDE).

Compressor, an instrument for the regulated compression of a minute object. The same
effect can be produced by a well-made live-box, or by pressure directly applied to the thin
glass covering an object by the handle of a mounted needle.

Cabinet. — A box or cabinet, containing a number of drawers, will be requisite for holding
the objects. Each drawer should be numbered or labelled to facilitate reference. The
objects should lie flat in the drawers, so that each may be found when required without

xxiv INTRODUCTION.

loss of time. The cabinet should be furnished with two folding doors, so as to exclude
dust as much as possible. It should also be made of thoroughly seasoned wood, oak or
mahogany being the best ; if made of deal or cedar, the vapour of the volatile oil of the
wood will insinuate itself beneath the thin glass cover and the slide in those objects which
are mounted in the dry state, and, condensing upon them and the objects, will obscure and
spoil them.

It may be remarked here that the names of objects should always be written upon labels
pasted (not gummed) to the slides, not merely upon the slides with a diamond. The
colour of the labels should be different for each kind of object; or if the labels be com-
posed of white paper, they should have a coloured margin ; thus those of the Desmidiacere
may be green, the Piatomacese yellow, £c., so that the various slides, when acciden-
tally mixed after comparative examinations, can be readily replaced in their respective
drawers.

Bell-ylasses. — The microscope when in use, either constant or occasional, should always
be kept under a large bell-glass, the base of which fits into an annular groove made in a
circular flat wooden stand. In this way it is kept from dust, and the trouble and wear
and tear consequent upon putting it into a box is saved. Moreover, thus protected, an
object under examination can be left without fear of injury or disturbance, and be also
preserved from dust.

Several smaller bell-glasses of various sizes should also be kept at hand, under which any
objects which it may not be convenient to mount for a time, or the examination of which may
not be completed, can be protected.

Slides. — These are ordinarily made of glass about the thickness of common window-glass j
their length is usually 3 inches, and their breadth 1 inch. The old length was "1\ inches,
which I prefer, as the longer slides, with a large number of objects, take up so much room ;
but as the aperture in the stage has been enlarged in the modern microscopes to allow of
the passage of the parabolic reflector, the Amici's prism, &c., if the old size be retained
the slides will drop through the stage : this we remedy by an additional brass plate.
Where the objects are very large, the slide must be proportionately large, and its thickness
greater than usual. The slides should be made of colourless glass, so as not to interfere
with the appreciation of the colour of an object. And they should be flat j otherwise the
parts of the object will lie in different planes, and every motion of the slide will require
new adjustment of the focus. The edges are best somewhat ground on a copper plate with
emery, to prevent injury to the fingers or scratching the stage-plate. Very delicate
structures require to be examined and mounted upon thin glass. The slides may then be
made of wood, sheet zinc, or tin-plate, with a circular aperture in the middle, upon
which a piece of thin glass is cemented ; or slides of 9~10-oz. crown-glass may be used.

Covers. — Comparatively few objects can be viewed in the dried state ; hence they are
most frequently immersed in some kind of liquid. To prevent the evaporation and conden-
sation of this upon the object-glass, and to reduce the thickness of the layer of liquid to a
minimum, the obj ect is usually covered with a piece of thin glass. The form of this cover is
either square or circular, and the thickness from about the :5V to the ?^$ °f an mcfy OP
even less. These covers are usually kept already cut by the microscope-makers and those
who sell objects. Before use, they are best allowed to remain immersed in water for some
time. Care is required in wiping this thin glass. It is usually effected by holding the
cover at two opposite points of the margin between the finger and the thumb of the left

DIPPING-TUBES-FORCEPS. xxv

hand, and rubbing the surfaces with, a fold of a cloth, leather, or silk handkerchief covering
the same parts of the right hand. But the thinnest glass cannot be wiped in this way
without being broken. This requires to be held at the edge by the finger and thumb of
the left hand applied to the flat surfaces, and to be drawn slowly through the fold of the
cloth in the hand. A very thin layer of mica is useful as a cover with the highest powers,
as it prevents the risk of scratching the object-glass, the lower surface of which is often
flush with the edge of the brass mounting.

Dipping-tubes. — These are glass tubes varying in length from about 5 inches to a foot,
and in calibre from £ to £ an inch. They are cut of the proper length by a three-square file,
and the ends gently fused in the flame of a spirit-lamp. One end is then coated outside
with sealing-wax and spirit, or some other coloured liquid, so that the same end may always
be used for the same purpose. They are of use for removing objects from water or other
liquids in which they may be contained. Suppose, for instance, it is required to examine
some deposit lying at the bottom of a liquid, or an object suspended : the fore finger of the
hand in which the tube is held is placed upon the upper end of the tube so as to close it ;
the other end is then immersed in the liquid and brought into contact with, or as near as
possible to the object, and the finger removed from the upper end. Hydrostatic pressure
then forces the liquid, and with it the object, into the lower part of the tube, and it can
be transferred to a slide. When a tube of narrow calibre is used, the liquid and object
are retained within the tube by capillary attraction ; they must then be removed by
gently blowing at the upper end, the lower end being placed upon the slide. The use
of colouring one end of the tube is, that the application of the mouth to the end of the
tube which has been immersed in some offensive liquid, as foetid water, &c., may be
avoided.

These tubes should be kept in a glass of distilled water, with the coloured ends
uppermost.

When a large tube is used, as in removing the larva of an insect, a tadpole, £c., the
quantity of liquid removed is also large, and will be more than is required on the slide.
The tube should then be emptied into a watch-glass, and the object placed upon the slide
or in the live-box by a camel's-hair pencil.

Forceps are in constant requisition for taking hold of minute objects, dissecting, &c.
Those used for medical purposes (common steel dissecting or surgical forceps) are best.
There are three points to be attended to in the selection of them. They should not be too
short, i. e. less than four inches in length at least ; the spring- (separating-) action should
be very feeble ; and the points should be perfectly flat and smooth where they come into
contact. If forceps are shorter than the above length, they are not easily held steadily :
if the spring-action be strong, on holding an object, as in dissection, with the forceps, the
attention being perhaps directed to the scalpel, needle-points, &c., the blades of the
forceps separate, and the object escapes from their grasp. If the forceps have teeth or
are grooved, perhaps after laying an object out upon a slide under water, or elsewhere, a
portion of it becomes entangled in the teeth, and the whole displaced. Surgical " tena-
culum-forceps " are very useful occasionally in injecting. These forceps lock bv their own
spring-action. Supposing, then, the injection is escaping from the orifice of some vessel
which has been overlooked and no assistant is at hand, on including the open end of the
vessel between the ends of those forceps, which may then be left hanging, it is firmly
fixed, and the operator has both hands disengaged to tie it ; in fact, these forceps are

xxvi INTRODUCTION.

indispensable to the injector. They should be short, and not heavy; otherwise the vessel
may be torn by their weight.

Surgical " dressing-forceps " are also frequently of use; and long tf oesophagus-forceps "
with scissor-handles are serviceable for removing portions of plants £c. from large jars or
glass vessels.

Needles. — For separating the parts of minute objects, fine points are requisite ; these are
found in common needles of moderate size fixed by one end into the handle of a water-
colour brush. These are easily prepared : the needle is cut in half by cutting-pliers ; the
blunt end is then forced into the stick, about half an inch in length being left projecting.
Surgeons' " cataract-needles " ground down are elegant instruments of this kind, but they
require to be shortened. For the minute dissection of objects, the mounted needles require
pointing on a hone.

A stout sable-hair or fine bristle, inserted into a slender wooden handle, is frequently of
use in isolating minute bodies, as Diatomacefle, which would be broken by any other instru-
ment. It is used thus : suppose we have a number of Nawcula, or the like, in a bottle,
mixed with other bodies, and we wish to isolate one for preservation. A small quantity
of the deposit is taken up with a dipping-tube, and allowed to escape upon a slide in such
manner as to form a narrow stripe upon it. This is then examined with the lowest power
with which the object can be distinguished, and one near the margin of the liquid stripe is
selected, and may easily be removed with the mounted bristle (under the microscope)
beyond the margin of the liquid. The remainder of the liquid is then wiped away with a
cloth, a little distilled water added to the small quantity of liquid left containing the object,
and the latter moved with the bristle into the middle of the slide. The liquid is then driven
off by heat, and the object is left on the slide ready for mounting. Or, when the matter is
dried upon the slide, any one of the minute objects being lightly touched with the dry
bristle will adhere to it ; and by gently pressing or rotating the bristle upon the middle of
a new slide, the object will readily be transferred to the latter. The Diatomacea) may be
easily isolated in this way.

Knives. — Ordinary dissecting-kuives or scalpels. The handles should be sufficiently
large to allow of being firmly held.

A particular and most useful kind of knife for producing thin sections of soft bodies is
that known as " Valentin's knife." It consists of two or sometimes three blades with their
fiat surfaces parallel, set in a handle. The blades can be fixed at any distance apart,
according to the thickness of the section required. It is drawn across and through the
substance, from heel to point ; the section remains between the blades, and is then removed,
either with forceps, or the blades of the knife are opened under water, and the section
floated upon a slide immersed in the liquid. In the latter case, the action of the water
upon the tissue must not be overlooked. Valentin's knife is absolutely indispensable in
the examination of animal bodies. Some sections, especially of plants, are best made with
a razor. Many sections can only be made by the aid of the " section-cutter " or microtome,
which is described under PREPARATION.

Black and white Disk. — A disk 3 or 4 inches in diameter, made of seasoned wood, and
upon one face of which a piece of white paper or card-board has been fastened by paste or
glue. One half of the paper or card-board is coloured black ;t he other is left white. This
is very useful in dissecting or separating minute portions of tissues ; if these are white,
they become much more easily distinguished than usual when placed (on a slide) over the
black part of the disk ; if they are dark, over the white portion.

LEADED CORK— EVA^OBATING-DISH— TEST-BOX, ETC. xxvii

Leaded cork. — Some structures require to be dissected under water, as, c. g., those
of insects &c. These should be fixed with pins upon a piece of cork, beneath which
a plate of lead, corresponding in size, has been fastened. In many cases it is advan-
tageous to dissect these tissues under the simple microscope. An aperture may then be
made in the lead and cork, and the tissue or structure stretched across the aperture, so
that the light may pass through it; or it may be illuminated as an opaque object by the
aid of the bull's-eye.

A trough, composed of five pieces of glass cemented together with marine glue, four for
the sides and one for the bottom, will serve to hold the water and the leaded cork.

Evaporating Disk or Saucer.— It is advisable to keep one of these, with a flat bottom,
always at hand filled with distilled water, in which slides and Covers that have been used
may be immersed. The remains of objects which have been examined are thus easily
separated from the glasses, and there is but little trouble in wiping the latter clean. If
held under a gentle current of water, all remains of tissues or test-liquids may be washed
away from the dish — the glasses, from their gravity, remaining at the bottom.

Test-box. — A wooden box, holding from six to a dozen or more test-bottles, is indispen-
sably requisite. The box must be divided into partitions corresponding to the size of the
bottles, and the latter must be wedged between these partitions so that the stopper can
bo removed without fear of disturbing the bottles. The box should be covered with a lid
furnished with hinges, so that no room may be required to place the lid when the box is
opened. The bottles will vary in size according to option ; but they should be of at least
1-ounce capacity. Each should have a stopper so prolonged as nearly to reach the bottom
of the bottle, its form being either conical or fusiform. The advantages of this form of
stopper are, that a mere trace or several ordinary drops of the reagent may be applied to
the object as required. If a very minute quantity be desired, the lower part of the stopper
is allowed to touch the inside of the neck of the bottle when it is withdrawn ; and if a
larger quantity be required, this proceeding may be avoided. Each bottle should be labelled ;
and a label should also be placed upon the upper end of the side or partition of the box near
to the bottle, so that the nature of the contents of each bottle may be ascertained without
removing it from the box, The general advantages of this apparatus are, that the quantity of
reagent required can be obtained to the greatest nicety, and it can be added to the exact spot
required with one hand only, so that the other can be employed to hold the slide and object &c.

Reayents or Test-liquids, — Some of these should be kept in the test-bottles ; but larger
quantities should also be kept in other stoppered bottles. We give a list here of those test-
reagents which are most frequently required j the method of preparing each, the strength,
&c. will be found under the respective heads.

1. Sulphuric acid. 2. Nitric acid. 3. Acetic acid. 4. Caustic potash, o. Chloride
of calcium. 6. Aqueous solution of iodine. 7. Oil of turpentine. 8. Glycerine. 9. Acid
nitrate of mercury (Millon's test-liquid). 10. Distilled water.

Benzole and alcohol or methylated spirit should also be kept at hand. Chromic acid
should be preserved in a wide-mouthed stoppered bottle, and its solution prepared when
requisite, as it easily becomes decomposed by dust &c.

Trow/Jis are flat, oblong glass boxes, without lids. They are made of pieces of glass
cemented together by marine glue, and are used in examining the larger aquatic plants or
animals in a living state, also in mounting objects.

c

xxviii INTRODUCTION.

Divided Scale. — A metallic or ivory scale divided into lOOths &c. of an inch, is indis-
pensable in micrometric admeasurements (see MEASUREMENT). The metal or ivory
should extend beyond the graduated portion.

Micrometer. — A glass slide with fine lines scratched upon it with a diamond, these being
loWtn of an inch apart, is absolutely requisite. Another, with coarser divisions, is also
required to be placed in the eyepiece, for making measurements (see MEASUREMENT).

A rectangular brass table, with two legs at one end and one at the other, is useful in
macerating objects upon slides iii chemical reagents, oil of turpentine, or Canada balsam,
and in mounting objects. It is heated by a small spirit-lamp placed underneath.

Ring-Net. — A very useful piece of apparatus for collecting Desmidiaceae, Diatomacete,
&c., where entangled amongst Confervre &c., or forming crusts or films upon other aquatic
plants, consists of a brass or wooden ring about 4 inches in diameter, furnished with a
groove round its circumference, in which also a radial aperture exists, through which
the end of a stick may pass. A piece of very fine muslin, rather larger than the ring, is
then laid over it, and the margins of the muslin fixed in the groove by means, of a vulca-
nized Indian-rubber band. Or this apparatus may be so modified, that the muslin is fixed
by means of an inner ring, adapted to the outer, but incomplete at one point of its circum-
ference, and with a projecting rim to prevent its passing through the outer ring. Thus \\\\
have a kind of strainer; and by using several pieces of previously wetted muslin in >iu -
cession, a large number of the minute organisms may be separated from the water. The
pieces of musliu may be brought home, folded up, in wide-mouthed bottles, separately. 01
several in one, according as the organisms are obtained from one or several waters. In
this way we save carrying a large quantity of water. The pieces of muslin are afterwards
opened and placed in jars of filtered river-water, and exposed to the light, when the
organisms will become detached.

A simple microscope, or some apparatus which will allow of dissection with the aid of
lenses, is essential, although the erecting eyepiece or the erecting-glass (p. xxii) will answer
the same purpose. It is of little consequence which be selected, provided a large and firm
sloping arm-rest be furnished on each side of the stage. Either doublets or the lower
powers may be used. Some of the modem simple microscopes are binocular,

Leather Case and Collecting- Bottles. — The Diatomaceee, Desmidiaceae, and other smaller
Algae, as also the Infusoria, require to be collected and brought home in bottles. These
should be of about 1 or 2 ounces capacity j and, for portability without risk of being
broken, they should be packed in a case made of stout leather, with a separate space for
each bottle. The whole will pack up in the form of a book.

Having given a sketch of the most important pieces of apparatus, we will say a few
w-ords upon the illumination.

Ittummation. — The best light in general for microscopic purposes is undoubtedly day-
light, or that of the sun reflected from the clouds j and this is certainly the light which
can be borne for the greatest length of time without injury to the sight. The position of
the observer is of importance ; it should be such that the window is on his left hand, or
even the back slightly turned towards the window. The advantages of this position are
great ; for then but little light will enter the eyes directly from the window, and it is of
the greatest importance, during a microscopic examination, that the least possible amount
of light should be admitted to the eye, from any source, besides that transmitted through
or reflected from the object. In drawing also with the camera lucidathis position should

ILLUMINATION. xxix

be strictly observed ; for all extraneous light which would interfere with the distinctness
of the image is thus excluded, and the shadow of the pencil and hand does not interfere
with or obscure the sketch in progress, which would be the case if the observer's right
hand were towards the window. But in daylight the light entering the eye from the
window, even in the position above mentioned, will interfere with the observation, unless
a preventive be employed, which is to place a screen, either supported upon a stand or
fixed to the upper part of the body of the microscope, between the eye and the eyepiece
of the microscope and the light. This screen may be made of card-board or thin wood,
covered with black velvet. If it be fixed to a moveable arm, like the lens of the side-
condenser, it may be easily placed in any convenient position. If to be fitted on the
microscope, it may be constructed thus : a piece of stout card-board, of about the size
and shape of one of the plates of this work, should have the corners rounded off, and
should be bent at a right angle at about the lower one-fourth ; a hole being cut in the
middle of the smaller portion, of a size just to fit the top of the body of the micro-
scope, a short tube of card-board is then made by sewing or pasting; and this, being
fastened in the same way to the circular aperture, serves to keep the screen in posi-
tion. The whole is then covered with black velvet. When used, the long flap should
be placed towards the left side ; it then shelters the eye and upper part of the eyepiece
from the light. A screen of this kind should always be kept upon the microscope ; for it
is of the greatest service. A tube made of a roll of card-board, fastened to the inside of
the angle of the screen described above, will serve to fix it to the stem of the side-con-
denser ; it may then be made to slide upon this axis or stem at pleasure. It is hardly
possible to use the high powers of the microscope by daylight without a screen of this
kind.

But few persons have the opportunity of using daylight for microscopic researches,
and with the highest powers ordinary daylight is by no means sufficient ; hence artificial
light of some kind is called into requisition ; and the most common source of this is an
Argand-lamp (Silber's) with oil ; used with or without a side-condenser. For ordinary
purposes this answers well, although the best for examining Diatomacese &c. is a paraffine-
oil or camphine lamp, especially when stops and very high powers and eyepieces are used,
whereby a large amount of light is intercepted. A cheap common beuzoline lamp with a
round or, better, a flat wick, is very advantageous, even with the highest powers (^V^h
Beale) ; the direct light being used. In Fiddian's lamp, the flame is enclosed in a metallic
case, so resembling a bull's-eye lantern, the light escaping from a round orifice only ;
hence no extraneous light can reach the eye. The lamp must slide up and down the stem,
so that it can be placed at any height ; and it should be furnished with a shade, also move-
able. A white-cloud earthenware or enamel shade is often used. Norman's paraffine-
lamp, and Collin's Bockett lamp, with an attached bull's-eye, and How's lamp, are good
lamps. An improved lamp, for illuniination and centering with high powers, is described
by Dallinger (M. Mi. Jn. 1876, xv. p. 165).

Much of the success with which the structure of an object is displayed will depend upon
the manner in which the light is thrown upon or transmitted through it. In general the
more light that can be condensed upon opaque objects the better; and when the various
parts of such objects are of different colours, the more direct the light and the greater the
angular aperture of the object-glass, the more clearly will the parts be distinguishable ;
while in certain opaque objects which present questionable elevations or depressions on

c2

xxx INTRODUCTION.

their surface, great obliquity of the incident light is essential. With transparent objects
it is sometimes desirable to diminish the amount of light more or less; which may be done,
cither by means of the diaphragm, by using the flat instead of the concave face of the
mirror, or by inclining the mirror to one side. It must not be forgotten, in determining
the cause of the better display of an object by the substitution of a less amount of oblique
light for a larger amount of direct light, that it need not necessarily arise from the
obliquity; for in many instances the cause is simply the diminution of tight, whether
direct or oblique being a matter of indifference. When the mirror has only one reflecting
surface, the amount of light may be diminished by removing the lamp to a greater
distance from the mirror, or turning this somewhat on one side. But the difficulty usually
found consists in the amount of light being too small instead of too great. This may be
overcome by attention to the following circumstances : the mirror must be placed as near
the lamp as possible ; if it cannot be brought within a few inches of the lamp, the shallow
bull's-eye condenser iniist.be made to condense the light upon the mirror : with the object-
glasses of high powers the achromatic condenser must be used ; and the lower the power
of the condensing lenses, the greater will be the amount of light transmitted. The lined
appearances presented by many objects, require for their exhibition very oblique light,
which may be obtained by first raising the mirror as near as possible to the plane of the
stage, and then bringing it as much to one side or the other of the stage as can be done.
Nachet's, Aniici's, or Reade's prism is very useful for producing the same effect in a greater
degree ; large angular aperture in the object-glass is also very advantageous under these
circumstances, because it will allow of the admission of rays of such a degree of obliquity
as could not enter one of smaller aperture.

In cases where still more oblique light is required than can be obtained in any way by
reflection from the mirror, this must be turned aside, and the direct light of the lamp
used, thus : clamp the slide so that the object projects beyond that side of the stage which
is nearest the lamp. The body of the microscope is then rotated so that the object-glass is
over the object and fixed by the milled head; the axis of the body being then directed to
the light, the object may be thus brought into focus; and by moving the lamp around the
microscope, light of any obliquity may be made to pass through the object. This is a
simple way of obtaining the most oblique light, and as the light conies directly from the
lamp, there is no loss from reflection, as in the use of prisms. By a little variation of this
arrangement, the light may be made to fall very obliquely upon opaque objects, especially
if uncovered. In many instances the use of the direct light of a lamp is highly advan-
tageous, and may be applied even when the highest powers are used. It has an advantage
over that of the mirror, inasmuch as when the latter is used, the light entering the object
is derived from two sources, viz. reflection from the outer and the inner surface of the
mirror ; whereby two images are formed, confusing each other ; while with the direct light,
the image is single and the definition finer.

Many years ago I suggested a method of remedying the defects of artificial light, or
that ordinarily used to replace daylight. The well-known glare attending lamp- or
candle-light, and the predominance of a yellow colour, so visible when compared with
daylight, render it very unfavourable for microscopic purposes. It was proposed to
mix some substance with the combustible which during its combustion evolved a light of
the colour complementary to (or forming white light with) that predominant in the arti-
ficial light, or to pass the light in its passage from the artificial luminary through a piece

ILLUMINATION. xxxi

of glass of such colour as to intercept or check the objectionable rays. As these rays are
of a yellow or reddish-yellow colour, the colour of the glass must be blue or purplish blue j
but the exact shade must be obtained by experiment. Thus: the lamp, or whatever
source of artificial light it may be, is lighted in the daytime, and the light transmitted
through the microscope by reflection in the ordinary way, when its intensely yellowish
colour is very obvious. Pieces of glass of different colours are then separately placed at
right angles to the path of the rays from the lamp to the mirror, either close to the flame
(in the form of an ordinary lamp-glass), upon the face of the mirror itself, beneath the
stage, or in an extra head of the side-condenser. If the glass be of the proper tint, and be
placed at the proper distance from the light, and in the proper situation, the field will
appear as white as the light of the clouds, which may be easily proved by altering the
inclination of the mirror so as to reflect the light of the clouds and the lamp alternately.

It may be remarked that the nearer the coloured glass is placed to the flame the less
apparent effect is produced, i. e. the more will the yellow colour be perceptible, and
vice versa. If the field still appear yellow, the glass is not of sufficiently deep colour ; if
it appear blue, the colour of the glass is too deep. The first method, or that of mixing
some substance with the combustible (oil, tallow, &c.) capable of evolving a light of the
requisite tint to form white with the yellow of the artificial light would be far preferable
to the latter method ; but I am not aware that any experiments have been made to carry
out this idea. It would have two great advantages, viz. that there would be no diminu-
tion of light, and that the entire apartment would be illuminated by a light equivalent to
that of ordinary day. The second method has one objection, which is, that it intercepts
a large quantity of the light, so that in the examination of those objects with high powers
which require intense illumination, or where much of the light is arrested by stops, it is
decidedly objectionable. The advantages which the use of the blue glass possesses are,
that it softens the h'ght very much, and that it enables the observer to discriminate
between colours as in ordinary daylight.

A few years after the publication of the above method, a patent was taken out for the
construction of lamp-glasses of a blue colour ; but they are of little service, merely slightly
softening the light, or intercepting a small proportion of the yellow rays. Perhaps,
some day, a small electric lamp, worked by clock-work, will be invented.

The proper way would be to "flash " the suitably tinted blue glass upon one side of a
pale blue lamp-glass, so that, by simply turning the glass round, the light might be trans-
mitted through either of the differently coloured portions. Rainey's " Light-modifier "
acts upon this principle. Numerous other pieces of apparatus and ingenious contrivances
will be found described and mostly figured in the last edition of Carpenter's ' Microscope/
or in Beale's ' How &c.'

The illumination is of importance to the microscopic observer in another sense, i. e. in
regard to the injury of sight. The great point here is to avoid too powerful a h'ght. An
eminent French philosopher became blind in experimenting upon the duration of powerful
impressions upon the retina. In some instances, sun-light has been used in microscopic
investigation ; the greatest care must then be taken to use screens or diaphragms to temper
the lisrht.

xxxii INTRODUCTION.

II.— GENERAL METHOD OF DETERMINING THE STRUCTURE OF MICRO-
SCOPIC OBJECTS FROM THE APPEARANCES WHICH THEY PRESENT
UNDER VARIOUS CONDITIONS.

Microscopic and histological Appearance, Structure, and Analysis. — Before proceeding to
this, let us define what is meant by the structure of a microscopic object. If we take a
piece of the free end of the finger-nail, and examine a thin transverse section of it under
the microscope, we find it to present numerous shorter or longer dark and somewhat
irregular lines running nearly parallel to the surfaces. These appearances do not vary
essentially whether it be examined in the dry state, or immersed in water or oil of
turpentine.

But when it is moistened with solution of potash, and allowed to remain so for some
time, or the slide is gently heated, it becomes entirely resolved into a number of nucleated
cells ; and by watching the gradual action of the potash, it is easily seen that the cells
were originally flattened and arranged in layers, which layers produced the lined appearance
mentioned above (see the article NAILS). Now which is to be considered as representing
the structure of the nail ? the first or the second of the above results ? Undoubtedly the
second. The expressions microscopic structure and histological structure are used very
indefinitely, and often synonymously j the former may very conveniently be restricted
to signify the apparent structure as determined with the aid of ordinary mechanical means ;
whilst the latter may designate the true structure in relation to development. It may at
first sight appear very unnecessary to inake any distinction between the two ; but it is
really very important, and many of the descriptions of the structure of bodies, given in
books, refer only to their microscopic structure. "

The determination of the histological or true structure is often very difficult. Frequently
a week or a month must bo devoted to the determination of a single point. Take the
instance of a hard structure — a piece of the skeleton of one of the Invertebrate, A few
sections may exhibit cells, laminae or fibres, according to the preconceived notions of the
observer ; whilst the histologist will not express an opinion until the inorganic matters
have been removed by long maceration in acid, the calcareous salts thoroughly washed
away, and attempts have been made to resolve the organic basis into its histological elements
by appropriate means. This may require very many experiments to be made, and no mean
knowledge of particular branches of science for guidance in the selection of appropriate
agents requisite for their performance. We shall have-frequent occasion to use the above
words in the restricted sense ; hence this should not be forgotten. The word analysis will
have the same meaning as that generally attributed to it, the ultimate products being
morphological.

A general method of determining the structure of objects can hardly bo laid down ; it
must vary so greatly according to the nature of the objects and their size. The first point
is to render them transparent, if not already so. This may frequently be done by immer-
sion or maceration, if dry, in \vater, glycerine, or oil of turpentine. But the solvent power
of the liquid must be borne in mind ; for the organic principle aleurone was overlooked for
years from its being soluble in water, in which the sections of the albumen of seeds con-
taining it were immersed to render them transparent. Sometimes the aid of heat is
necessary ; and objects may even require to be boiled in these liquids, either upon a slide
placed upon the brass table over the flame of a spirit-lamp, or in a small tube. Sometimes

MICROSCOPIC ANALYSIS. xxxiii

sections require to be made, and these treated in the same manner, If soft, their elements
may be separated by the aid of needles; sometimes pressure will answer the same
purpose.

When the object is very minute, it will frequently be desirable to examine both sides
of it with high powers. Hence it must not be placed upon an ordinary slide, on account
of the thickness of the latter, but it must be supported upon, and covered by thin glass.
The best plan is to keep a number of slides of thin wood or tin, each having a piece cut
out of the middle. A thin glass cover, rather larger than the aperture, should then be
cemented by marine glue or Canada balsam to the slide ; the thin glass cover is then
applied as usual.

If the object be very small and its structure very delicate, it must be crushed, so
that some of the fragments may lie perfectly flat upon the slide, See also the article
PREPARATION,

The points to be determined in regard to the different parts of an object, however, may
be best treated separately.

The examination of a microscopic object must comprise : — a, the microscojric analysts,
including — 1, the form ; 2, the colour ; 3, the structure of the surface ; and 4, the internal
structure : b, histological analysis, in the sense already explained : c, the qualitative chemical
composition : and </, the measurement.

A. MICROSCOPIC ANALYSIS.

1. The Form. — a. This is usually judged of from the outline as seen by transmitted
light, and often erroneously. Where a low power is used, the upper surface of an object
and its sides are mostly simultaneously visible ; but under a high power, only those parts
lying within a very limited vertical range, or in the same plane, are visible at one focus,
and the parts lying in planes above or below this can only be brought into view by
altering the focus : hence the views of objects under high powers correspond to views of
transverse sections of the same objects made through various horizontal planes; and as the
margins of objects are usually more distinct by transmitted light than the upper surface,
spherical or rounded bodies frequently appear flattened. When several bodies of the same
kind are visible in the field of the microscope, some will almost always be found lying upon
their sides ; and even when the objects are greatly flattened, some will mostly be found
lying on edge, presenting the side view,

b. But as there may be uncertainty in regard to the relation of these bodies to each other,
the only safe method in forming a conclusion is to cause them to revolve or roll over, so
that all their aspects may be distinguished. This is in general easily accomplished : if the
object be already immersed in liquid, the inclination of the stage will answer the purpose;
or a little benzole, naphtha, alcohol, or some other volatile liquid in which they are
insoluble, must be added. The currents produced by the evaporation of these will cause
the objects, especially such as are near the edges of the liquid, to move in all directions,
and their true form may be discerned. Sometimes moving the thin glass cover sidewise,
the object being kept in view, will answer the same end.

c. In figures of microscopic objects, the side view should always be exhibited or
described.

d. In the case of crystalline bodies, or such as present angular edges, their angles should
be measured with the goniometer, if their chemical composition be unknown,

xxxiv INTRODUCTION.

'2. The Colour. — The colour of objects should always bo carefully described, and its
fa i ISP accurately determined. It most commonly arises from: — 1, partial absorption; ~2,
the presence of pigment, or other colouring matter ; 3, from iridescence ; 4, from polari-
zation, &c.

(1.) The most common cause is a peculiar property by which a portion of the coloured
rays composing the white light which falls upon or is transmitted through an object is
absorbed, the remainder being reflected or refracted so as to reach the eye. On examining
bodies thus coloured, with whatever powers, their substance is found uniformly coloured,
and this colour i* unchanged by their immersion in water or oil of turpentine, and is the
same in transparent bodies by both transmitted and reflected light. This is commonly
regarded as the proper colour of an object. Example : a crystal of blue vitriol.

(2.) a. In many cases, however, although an object may appear to the naked eye
uniformly coloured, on examining it with a high power, the colour, which in fact aii>rs
from the above cause, is seen to be confined to certain molecules or granules, whilst the
general substance is colourless. These granules may consist of vegetable or animal colour-
ing-matters, metallic oxides, &c. The nature of these matters should always be determined,
if possible, either by microscopic chemistry — micro-chemical analysis, as it has been called,
— or by ordinary chemical analysis. When the colouring-matter is of organic nature, and
when its composition cannot be determined, or it has no definite name, it is c&Hedjn'ffmenf.
Objects coloured by pigment, metallic oxides, or other colouring matters, are best examined
by direct (not oblique) transmitted light, and when immersed in either water or oil of
turpentine. These liquids do not change the colour, nor destroy it unless the pigment be
soluble in them ; but by rendering the general substance of the object more transparent,
they cause the granules to become more distinct. The colour is the same both by
transmitted and reflected light. Example : a brown or black hair of an animal, as the
mouse.

6. Sometimes bodies coloured by pigment or other colouring-matters appear under the
microscope uniformly dyed, although the colouring-matter consists of an insoluble molecular
or granular powder — as a white animal hair first macerated in solution of ferrocyanide of
potassium and then in solution of perchloride of iron. Chemical means will alone
distinguish this cause of colour from the first, by removing the colouring-matter from the
colourless basis.

(3.) The colours of many objects vary according to the direction of the light transmitted
through them, or are only visible by oblique light, and the colours are different by direct
and oblique light. These arise from decomposition of white light by either interference or
refraction. For the sake of brevity, these may be designated colours from iridescence,
because they mostly exhibit the brilliancy and transparency of the colours of the rain-
bow. The interference or refraction upon which they depend is ordinarily produced
by irregularities of structure, frequently depressions or grooves, and sometimes cavities
containing air, &c. Objects exhibiting these colours, which are most brilliant by very
oblique light and under low powers, when examined with a moderately high power by
transmitted direct or but slightly oblique light, frequently appear more dull and less
brilliant, often dark or black in parts ; and when immersed in oil of turpentine, or some
liquid approaching in refractive power the substance of which they are composed, so that
their irregidarities become filled with it, the colours vanish. Hence colour, when arising
from iridescence, can readily be distinguished from that arising from general absorption

MICROSCOPIC ANALYSIS. COLOUR. xxxv

or from the presence of pigment ; and when the colour of an object obeys the above law,
it may be predicted that structural irregularities sufficient to account for its production
will be found if properly sought for. Moreover these colours are not the same by
reflected and refracted light, and they vanish under very high powers. They may be
studied in the species of Phurosiyma ; and those observers whose microscopes do not
magnify sufficiently, or whose object-glasses have not sufficient angular aperture to admit
of the detection of the markings upon some of the LHatomacese or other bodies of similar
structure, may be sure that they are present when these phenomena have been observed.
We were thus led to search for them upon the valves of Melosira varicms and Eorreri,
species of Nitzsckia, £c., where they had not been previously detected ; and there they
are present. Again, the colours of the dried valves of the Diatomacese, many of which
have a brown tinge, have been supposed to depend upon the presence of the peroxide
of iron j but as this colour vanishes when the valves are immersed in oil of turpentine,
independently of the fact that the valves do not present the same brown colour by
reflected and transmitted light, and by direct and oblique light, which we have stated to
be characteristic of the presence of colouring-matter, the colour cannot arise from this
cause.

An example of iridescent colour arising from the presence of fibres, is found in the
tapetum. Certain cases, referable to this head, require special notice. Thus it sometimes
becomes a question whether a very minute red spot, visible in an Infusorium, Alga, &c.,
is the optical expression of a minute vacuole, or a little depression filled with water, air,
or other fluid of less highly refractive power than the substance of which the organism
consists, or whether it arises from the presence of pigment. The point is easily decided :
a practised eye will recognize the transparency of the colour where not arising from
pigment, and its granular appearance where the pigment is present. If the substance of
the object be soft, compression will frequently destroy the appearance when pigment is
absent. Drying the object and then immersing it in oil of turpentine or other highly
refractive liquid will do the same, whilst pigment will become even more distinct if present.
Moreover, on altering the focus of the object-glass, the colour will be found to change,
when not arising from pigment.

The colours of thin plates are so rare in microscopic objects, that we must refer to works
upon optics for an account of them. They occur in the crystals found upon the surface of
the scales of various fishes, the eggs and wings of insects, &c.

(4.) The colour arising from polarized light is noticed under ANALYTIC CRYSTALS,
DICHROISM, and POLARIZATION.

The colours of objects examined by transmitted light are frequently rendered much
darker, and colourless or coloured objects may appear dark or even quite black, from
refraction or reflection of the light out of the field of the microscope. Thus powdered
vermilion appears almost black; air-bubbles appear black at the margins or entirely
black, &c. : hence the importance of comparing observations made by both reflected and
transmitted light ; for neglect of this precaution caused the air in the hairs of animals to
be mistaken for pigment. Milk-white opacity mostly arises from the presence of numerous
molecules, granules, thin layers of liquid or other surfaces which reflect a large quantity
of the light incident upon them, as in milk — where the reflecting bodies consist of the
globules of fatty matter (butter), — white paper, tubercle, &c.

3, Structure of the Surface. — «. When an object is of comparatively large size, the

xxxvi INTRODUCTION.

structure of the outer surface is in general easily determined by examining it with reflected
light, i. e. as an opaque object illuminated by the Lieberkiilm or side-condenser ; but when
the objects are small, sufficient light cannot be thrown upon them with ordinary conden>«'i - :
recourse must then be had to the opaque reflectors mentioned at p. xxi.

b. The appearances presented must also be controlled by those resulting from the action
of transmitted light. And here we meet with a difficult task, in accomplishing which, the
f olloAving questions are constantly presenting themselves : — Do certain spots, lines, or other
markings visible upon the surface represent elevations or depressions ? Are they cavities
in the outer portion or layer of the object ? Are they foramina or holes ? Are they
granules of pigment, or rows of them ? Do the lines represent a true lined structure, or
are they optical illusions ? Is the surface smooth and free from markings ? The methods
of answering these questions must vary so greatly, according to the nature of the object,
its size, &c., that it would be almost impossible to lay them down by rule. The following
considerations, however, are of most importance.

c. In many cases where structural appearances are visible at the surface of an object,
their true situation above or beneath the surface may be determined by raising the object-
glass above the focus of the surface. On then carefully and gradually depressing the
object-glass with the fine movement, the structure first brought into focus is the uppermost.
Thus, the inner surface of the under menibrame of the elytrumof the stag-beetle (Luctuiu*
cervus) is covered with very minute hairs projecting from the surface (PI. 34. fig. 2). On
placing this with the inner side uppermost and adjusting the object-glass as just
described, the hairs are distinctly brought into focus before the surface of the membrane.
Hence they are situated upon the surface ; whereas, had the surface of the membrane
been brought into view before the hairs, it must have been concluded that the latter
were situated on a plane below this. It may be stated that the surface of a membrane is
recognized to be in focus by certain irregular granules, molecules, or wrinkles mostly
visible upon it.

d. Frequently, when hairs, filaments, ov spines project from a surface, their relative
position may be determined by examining the margin of the object if it be rounded, or
the margin of a fold if it be flat and membranous — as in the case of ciliated bodies,
Infusoria, &c.

e. Cilia upon the surface of an object are sometimes so minute and transparent as to be
with difficulty detected ; they can however always be made evident, when present, by the
following means : — 1. Drying the object j they then become much darker from refraction.
2. Dyeing the object with solution of iodine; drying the object after the addition of the
latter solution is sometimes advantageous. 3. Mixing insoluble coloured particles, as those
of lampblack, or Prussian blue, with the water in which the objects are contained; of
course this is only of use if the objects be living; the particles will then be set in motion,
and their motion may be distinguished from molecular motion by the definite direction in
which the particles move.

/. The nature of many markings, spots, &c. in transparent objects is best determined
by Dujardin's method, viz. that of comparing at different foci the effects of the refraction
of the transmitted light produced by the markings themselves, and the substances in which
they are situated ; and these phenomena may be conveniently illustrated by their occurrence
in known objects. If a drop of oil of turpentine, which has been digested with alkanet
root so as to become coloured, be placed upon a slide, a drop of water added to it, a thin

MICROSCOPIC ANALYSIS. SURFACE. xxxvii

glass cover applied, and the cover be moved backwards and forwards upon the slide with
the linger covered with a cloth, the drop of oil will be subdivided into globules of various
sizes, some of which will enclose globules of water ; thus we shall have globules of the
oil surrounded simply by water, globules of water enclosed in globules of oil, and some of
these globules will contain, within them globules of the other kind again, the globules of
oil being readily distinguished by their red colour. On examining the slide with a tole-
rably higli power, all the globules will appear bounded by a black circle, and present a
luminous point in the centre, when viewed separately and the focus suitably adjusted for
each. But when they are examined in comparison and together, they will be found to
exhibit characteristic appearances according to the variation of the focus. Thus, of the
simple globules, when their margin is most distinctly brought into focus, some will become
more luminous as the object-glass is depressed (PI. 49. fig. I a) — these are globules of
water surrounded by oil ; others will become darker under the same circumstances (PL 49.
fig. 1 6), and very luminous as the object-glass is raised (PI. 49. fig. 1 c) — these are globules
of oil ; and the nature of the components of the compound globules may easily be deter-
mined by the occurrence of the same phenomena. The globules of oil being more highly
refractive than the water, act like little convex lenses ; whilst the globules of water sur-
rounded by the oil, exerting a lower refractive power than the latter, act like concave
lenses, and their centre appears luminous because the rays which traversed them diverge
as they ascend, as if they emanated from a (virtual) focus situated beneath the globules, or
on the same side of them as the mirror. Hence these foci may be distinguished as the
" lenticular foci " of the objects. And when dots or markings upon objects are very
minute, frequently all that can be distinguished under the microscope are these lenticular
foci of the various parts.

The same phenomena may be observed in air-bubbles immersed in water ; these corre-
spond with the globules of water surrounded by the oil. It need scarcely be remarked
that the object in colouring the oil is to allow of the control of the conclusions arrived at.
g. In the globules of sarcode or protoplasm and many cells, the vacuoles are easily shown,
by the same method, to be filled with a material of less refractive power than the general
substance of which they are composed : these vacuoles are frequently mistaken for nuclei
and nucleoli ; but they are readily distinguished from them by the dark appearance they
present when the object-glass is raised above the focus of their margins.

h. The above principles are applicable to the determination of numerous cases where
the elevation or depression of a spot or marking upon a surface is called in question ;
for elevations on a surface will produce the general effect of convex lenses, whilst
depressions will produce that of concave lenses. In the above experiment, plano-convex
lenses of both oil and water are frequently seen, and readily distinguished by the above
means.

Take also the instance of a Paramecium aurelia, either dried or immersed in water.
The surface is beautifully marked with pretty regular dots, which appear luminous as the
object-glass is depressed (PL 32. fig. 1 «), and dark as it is elevated (PL 32. fig. 1 6) ; hence
they consist of depressions upon the surface. Had they been elevations or little tubercles,
they would have become more luminous as the object-glass was raised, and vice versa.

When an isolated granule of pigment or of any opaque substance is brought into focus,
on raising the object-glass a luminous spot appears to occupy its place ; hence it agrees
so far with a highly refractive granule. The appearance, however, arises from diffraction,

xxxviii INTROD UCTION.

aud may usually be distinguished from that produced by refraction by the luminous spot
equalling or exceeding the granule in size, whilst in the latter it is smaller and more
brilliant.

i. In all these experiments the less oblique the light the more certain will be the results.
But this method is inapplicable to decide whether the less refractive portions are simply
depressions or cells. This may often be determined by examining the margin of the object
where possible (as in Faramecium), and observing whether there are depressions upon it
corresponding to the parts at which the dots are situated, and whether these depressions
are continuous with the dots (PI. 32. fig. 1 6). When the substance of the object is some-
what firm, drying it, if moist, will cause the dots to become filled with air ; they will then,
if cells, appear infinitely blacker than if simply depressions, and visible as readily by direct
as by oblique light ; and after the object has been moistened with water or oil of turpentine,
if it be immediately examined, the blackness of the dots will appear still greater, and they
will be distinctly visible by direct light ; whilst depressions are much more easily filled
with liquid, and then, if minute, will only be visible by oblique light.

In relation to this matter, the meaning of the " optical section " of minute objects viewed
under the microscope is important to be considered. Taking a globule of oil, or a pollen-
grain, and bringing the object-glass to focus upon the upper surface, at first the portion of
the surface which is in focus is visible; on lowering the object-glass, the surface becomes
invisible or indistinct, while a portion of the margin comes into focus, forming a ring.
This enlarges until the most convex portion is reached, when it diminishes until the lower
portion of the globule or grain is visible. In this way we obtain the same views of the
object, as if so many transverse sections or planes were examined. The better the correc-
tions of the object-glass, and the larger the angular aperture, the more distinctly will these
phenomena be developed.

k. If it can be shown that the parts corresponding to the dots are depressed below the
general surface, and the dots or depressions present an angular outline, these dots cannot
possibly represent cells, because, if the angularity of the outlines of cell structures arose
from the pressure of surrounding or adjacent cells, this pressure would necessarily be ex-
erted also upon the free or external portion of each cell, so as to render it convex, or at
any rate not concave. The firmness of the substance of the object must be attended to,
because, where it is absent, as the cells part with the liquid portion of their contents the
outer portion of the cell-wall may become approximated to the inner, and thus no space
be left for the air to enter, as in the exuviae of a Triton for instance.

/. In brittle objects, as the siliceous valves of the larger Diatoinaceae, the examination
of the margins of crushed and perfectly flat portions is important and sometimes conclusive ;
for it may be found, as in Isthmia (PI. 17. fig. 26) £c., that the depression of the object-
glass requisite to bring into focus the margins of the thin depressed portion is much greater
than that required for the intermediate thicker parts. In the valves of the more delicate
Piatomacese (Pleurosic/ma £e.), in which this observation is difficult to be made, the point
is important that the line of fracture of the broken valve passes through the rows of dark
dots or the lines corresponding to them, showing that they are thinner and weaker than
the rest of the substance : had these dots represented elevations, the valves would have
been stronger at these parts. The nature of the markings upon the siliceous valves of the
Diatomacese, especially the species of Pleurosiyma, has long formed a disputed point. In
distinguishing in general minute points, as the little siliceous spines of the cuticle of Equi-

MICROSCOPIC ANALYSIS. SURFACE. xxxk

setum, the very short spines on the wings of many insects (Tipidida &c.), or the minute
spheroids in Schultze's siliceous films, it may aid somewhat to remember that prominences
are usually most distinct under open central illumination, while depressions are most evi-
dent under the central-stop illumination. If we take a flat fragment of an Isthmia, and
examine it by the aid of the condenser with a central stop and an object-glass of lower power,
care being taken that the condenser and stop are perfectly central, it will exhibit a series
of angular dark or black dots bounded by luminous lines separating them (PI. 15. fig. 47),
and this when all parts of the object are best in focus ; for when the object-glass is elevated
or depressed, the whole becomes indistinct. The black dots in this instance clearly coin-
cide with the depressed portions of the surface of the valve. The same phenomena may
be observed in many other Diatcrnacere, as Triceratimn (PI. 17. fig. 29), Coscinodiscus
(PI. 51. fig. 1), &c. But when we examine those which have very fine markings, as the
valves of Pleurosiyma (PI. 15), the appearances vary greatly, according1 to the method of
illumination. The dark lines (PI. 15. figs. 10, 12, and 25), which are brought to view by
oblique illumination, correspond to the rows of the black dots of Isthmia (the thinner and
weaker portions of the valves), and with stop-illumination are resolved into the separate dots
(PI. 15. fig. 40), the rest of the valve appearing white and uniform. But at a different
focus, especially under immersion-lenses, the white portions of the valve present the
appearance of rows of bright pearls (PI. 15. fig. 40), the other portions of the valve appear-
ing dark. The same brilliant pearls are seen in the finer valves of Coscinodiscus Avith the
open central illumination. The article DIATOMACEJE must be consulted for further details
in regard to the structure of these valves, and the article ANGULAR, APERTURE in regard
to the changes produced in the appearances of objects by variation of the angular aperture
of the object-glass, and of the degrees of obliquity of the transmitted light. But we may
remark here that these dots must not be compared to cells, but to the depressions found
upon the seeds of the white poppy, Paramecium, £c., in which forms resembling those
resulting from the mutual pressure of adjacent cells are present, but do not arise, so far as
we know, from this cause.

m. No special remarks are required in regard to furrows, as these are only elongated
depressions.

n. When ridges are present, these are frequently left projecting at the margin of a frag-
ment ; sometimes they project naturally ; and it may readily be known that they are thicker
portions of structure, by their blacker margins and their exhibiting the characters of elon-
gated convex or plano-convex lenses.

In some cases, the position assumed by confined portions of air, when the object is im-
mersed in liquid, will denote the existence of ridges. Thus we have seen portions of aity
accidentally confined between the surface of a scale of Lepisma saccharina and the thin
glass covering it, assume an elongated form, being limited laterally by the ridges upon the
scale (PL 34, fig. 3).

o. Foramina or holes are in general readily distinguished by their dark and defined
margins, and the absence of colour when they exist in coloured structures $ when existing
in transparent colourless objects, the latter mostly exhibit minute irregularities, by which
the presence of some kind of matter is indicated, whilst these are absent in the foramina,
Where there is difficulty in deciding, the structure should be broken, if possible, and the
margins examined. Sometimes the polariscope is of use: the general substance may

xl INTRODUCTION,

polarize light; but of course the foramina will not do so. Charring the structure, or
colouring it with reagents, if organic, will sometimes afford decisive proof.

Foramina cannot bo mistaken for elevations on the surface, because they do not become
more luminous as the object-glass is raised after their margin has been brought most
distinctly into focus ; in fact the reverse occurs : hence they so far agree with depressions ;
but they differ from these in their luminous appearance with high powers, and their not
being rendered more distinct by oblique light, but the reverse.

p. When the structure in which they are situated is somewhat thick, and they form
rather tubes than foramina, as the axes of these can hardly coincide with the direction of
the transmitted light, their orifices will appear dark or black ; hence they might be mis-
taken for granules of pigment : immersion or maceration of the structure in oil of turpen-
tine, however, will fill them, and cause the dark appearance to vanish, whilst pigment
would still be visible. Examination by reflected light will also readily distinguish the
one case from the other. Also where this tubular structure is present, perpendicular sec-
tions will exhibit f urrows, which may be recognized as directed above. In distinguishing
foramina, the higher the power employed the less is the difficulty.

q. It has sometimes to be decided whether certain dark lines visible at the surface of
objects, represent ridges or grooves, or whether they are illusory shadows arising from the
passage of light through a structure furnished with depressions, granules of pigment, &c.
This must be done by examining the object when illuminated by reflected light, or a hollow
cone of oblique rays, such as is obtained on using the achromatic condenser with the cen-
tral stop j when thus illuminated, the lined appearance will vanish, and the true structure
will become visible.

r. It often happens that objects, especially highly refractive bodies, appear surrounded
or covered by a number of black lines, rings or annular lines, arising from diffraction, and
it becomes an important question whether these lines represent cell-walls, rows of dots,
&c. When they arise from diffraction, they vary in number according to the obliquity of
the incident light and the angular aperture of the object-glass ; and when the condenser
is used, they vary according to its adjustment, and at a particular adjustment they will
sometimes disappear entirely. Hence in these cases the condenser should always be used,
and the results obtained controlled by the effects of immersion in highly-refractive liquids,
and the means mentioned below.

s. A very ingenious method has been proposed and adopted successfully by Weiiham,
for exhibiting the form of certain very minute markings upon objects. A negative photo-
graphic impression of the object is first taken on collodion in the ordinary way, with the
highest power of the microscope that can be used. After this has been properly fixed, it is
placed in the sliding frame of an ordinary camera, and the frame-end of the latter adjusted
into an opening cut in the shutter of a perfectly dark room, Parallel rays of sun-light are
then thrown through the picture by means of a flat piece of looking-glass fixed outside the
shutter in such a manner as to catch and reflect the rays through the camera. A screen
standing in the room, opposite the lens of the camera, will now receive an image, exactly
as from a magic lantern, and the size of the image will be proportionate to the distance.
On this screen is placed a sheet of photogenic paper intended to receive the magnified
picture. A portion of the valve of a Plearosiyma magnified in this manner is represented
in PI. 15. fig. 41.

4. Internal Structure, — We must be understood here as referring to the general structure

MICROSCOPIC ANALYSIS. INTERNAL STRUCTURE. xli

of an object, i. e. whether it is solid or cellular, &c. ; and where an object is composed of
an aggregation of similar parts, our remarks must be applied to these individually.

The first question arising is whether a transparent object is solid or seniisolid and homo-
geneous, or whether it represents a cell, i, e. has an outer membrane or cell-wall and con-
tents of a different nature. When objects possess an outer coat, its two margins are
sometimes easily distinguishable on examination by transmitted light, especially when its
thickness is considerable. But when the outer coat is thin, these are difficult to distinguish ;
recourse must then be had to other means than simple inspection ; and these will vary
according to the nature of the object, and especially the softness of its cell- wall. Some-
times crushing it may show clearly that the contents consist of a liquid with numerous
molecules and granules, and that the cell- wall is thin and membranous j for the subsequent
addition of water may separate and render both distinct. The most valuable testauethod,
however, is the production of endosmosis or exosmosis. If we take a cell with a soft and
thin wall, and add distilled water to it, it will imbibe a certain quantity of it and become
distended, and often the contents will become distinctly separated and visible within j
whilst if a saturated solution of some salt, as chloride of calcium, be added, it will become
wrinkled and collapsed. On treating a solid or homogeneous body with water, it remains
unaltered, or perhaps swells slightly ; but on treating it with the solution of chloride of
calcium, no wrinkling or contraction occurs, and its appearance is unchanged. If the
outer coat be firm and resisting, the chloride will not cause it to contract and wrinkle.

If there be two coats, the outer being firmer than the inner, the latter will be wrinkled
and collapsed, while the former retains its shape ; this is the ordinary occurrence in young
vegetable cells. The exosniotic effects of the chloride of calcium should be looked for soon
after its addition to the object, particular care being taken that it comes into contact with
the object; for when solid or seniisolid bodies are macerated for a long time in the saline
solution, they will become contracted, and globules of sarcode will escape from them j but
we believe that in all these cases there really exists a cell-wall, or a structure corresponding
to it ; hence by solid or seniisolid bodies, we must be understood to mean those which
differ from cells according to the characteristic action of exosmose,

It must be remembered that solution of chloride of calcium is a highly refractive liquid ;
hence it frequently renders globules so transparent that they are almost or completely
invisible, and thus apparently dissolves them j sometimes also it really dissolves them.
Moreover many so-called unicellular vegetable organisms exhibit the contraction of the
internal cell-wall or primordial utricle, from long maceration in water only, as is so fre-
quently seen in the Desmidiaceae " mounted " in water. An aqueous solution of iodine
is also frequently useful in bringing to light the existence of an inner cell- wall, especially
in vegetable structures, causing it to become wrinkled and collapsed.

Cells have not the tendency to fuse together or adhere to each other, which globules of
sarcode or other glutinous solid or seniisolid substances have.

If the object be brittle, crushing it will sometimes show its internal structure, by allow-
ing the examination of the margins of the fragments.

Spherical or rounded solid bodies, when immersed in water or other liquids of low
refractive power, generally present a much less distinct black margin than cellular bodies,
or those with membranous walls.

The determination of the contents of an object furnished with an outer coat, must be
made according to the foregoing indication?. The contents often consist of liquid in which

xiii INTRODUCTION.

are suspended molecules and granules. If these exhibit molecular motion, the material in
which they are suspended must be liquid. It sometimes becomes a question whether a
body enclosed within another is central or lateral. This is readily determined by causing
the body to revolve by inclining the stage of the microscope, when, if central and fixed,
the enclosed body will retain this position ; and if it be less than the cavity of the enclosing
structure, positive indication will be afforded that the latter is solid, or at least that it does
not consist simply of an outer coat with liquid contents and the enclosed body. But if it
be attached to the inner wall of the enclosing structure, the eccentricity of its motion
whilst revolving will be evident.

The contents of microscopic bodies are frequently rendered distinct by the addition of
reagents, and in some cases can only be distinguished by their use ; thus the nuclei of
animal cells are at once made evident by the addition of acetic acid, &c.

The micro-spectroscope is often used in detecting small quantities of different substances
(SPECTROSCOPE) .

We frequently have to decide whether the interior of an object is solid or tubular. If
it consist of a firm substance, drying it, if in liquid, will cause the evaporation of the liquid
or other contents, and the entrance of air. A section of it will also show whether it is
solid or hollow. The effects of crushing it should also be observed.

An important aid in describing the structure of many objects, the components of which
are of so nearly similar refractive power as to be undistiuguishable by any variation in
illumination, is that of dyeing or staining. Different portions of a structure often have a
variable affinity for colouring-matters or dyes, and can thus be readily distinguished.
The various appropriate dyes are mentioned under the tissues, and the process under
STAINING.

B. HISTOLOGICAL ANALYSIS.

This consists in the resolution of the object into its component morphological elements,
and is usually effected by subjecting it to the action of various chemical reagents, continued
maceration, &c. It must never be attempted if inorganic matters be present in quantity,
until these have been previously removed. The reagent used should be one which exerts
a solvent action upon the substance of which the object is composed, the action being
interrupted at a certain stage by the addition of water, &c. In regard to those objects
whose morphological elements have become altered by individual growth, &c., histological
analysis is of course useless, and the manner in which these have acquired their existing
structure can only be determined by tracing the gradual changes which their morpholo-
gical constituents undergo, from the earliest period of their existence to that at which
they form the object in question. This constitutes the study of development; or it might
be termed Histological synthesis. It can rarely be followed directly, but may often be
carried out indirectly by examining a number of the objects in all stages of their develop-
ment, and comparing the changes undergone by their constituents. It requires special
care in controlling the identity of the objects.

0. CHEMICAL .REACTIONS,

We cannot too strongly insist upon the necessity of investigating these in the case of
all objects submitted to examination, the nature of which is at all doubtful — and this
because in many instances the form or general appearance will afford no criterion by which
the nature may be determined. Judgment founded simply upon the form, or upon the

CHEMICAL REACTIONS. xliii

mere inspection of an object, therefore, will illustrate the abuse and not the proper use of
the microscope. The quantitative and ultimate analysis of substances cannot be made in
any manner by the aid of microscopic manipulation ; but the qualitative analysis, or the
study of the action of chemical reagents upon the object or substance by the aid of the
microscope, or micro-chemical analysis, may be undertaken with the prospect of almost
certain success, in most cases at least, in ascertaining the proximate chemical composition.

The characteristic reactions or tests for the various proximate principles are given in
this work under the respective heads of those substances ; and we can here give only a
brief sketch of the manner in which the micro-chemical analysis of a substance may be
conducted, and without which its microscopic investigation must be imperfect and of little
or no value.

The first point to be attended to is, to ensure, as far as possible, the freedom of the
object from foreign admixtures. Thus, if it should have been found in an animal or vege-
table liquid, it must be carefully washed, either in a watch-glass or upon a slide whilst
covered with thin glass. The former is readily accomplished : the substance being placed
in a watch-glass, water or other solvent of foreign matters is added ; the whole is then
set aside, to allow of the subsidence of the substance, and the supernatant liquid removed
by a pipette. If the body or the particles be very minute, it or they must be placed upon
a glass slide, and covered with thin glass ; the latter should then be pressed, so far as is
possible without crushing the particles, but sufficiently to fix them, and a small piece of
coarse white blotting-paper placed upon the surface of the slide, so as to touch the
edge of the liquid ; capillary attraction will cause the liquid to be absorbed by the paper.
Small quantities of water, or other proper solvent, are then added by small portions from
the end of a glass rod to the opposite edge of the liquid confined by the thin glass. Thus
a current will be set up, and the newly added liquid will be absorbed by the blotting-
paper, washing in its course the particles confined between the two glasses. The current
will be regulated by the quantity of liquid added, and the facility with which the paper
absorbs it.

"When the body has been washed, the effects of the various reagents may be examined,
by the addition of them in small quantities from the conical stoppers of the test-bottles
(see Test-box, p. xxvii). The test-liquid being applied to the edge of the liquid in which
the body is immersed, gradually mixes with it, and the effects produced may be watched
step by step. If a solvent or other action is seen to take place, the result is decisive ;
but if no action be evident, it must be remembered that the reagent added may not have
reached the object under examination, perhaps from an insufficient lapse of time for the
occurrence of diffusion in the two liquids. To be positive, therefore, that the reagent has
no action upon the object when none is at first apparent, as much as possible of the liquid
in which it is immersed should be removed by blotting-paper ; or the liquid be gently
driven off by evaporation ; or, if the object be of sufficient size to ensure its not being lost,
the thin glass should be removed, and the whole, or as much as possible, of the liquid
removed either by the blotting-paper or evaporation. On then covering the object
with the thin glass, and adding the reagent to the edge of the latter, there can be no
doubt of its coming into contact with the body; and the result may be considered
decisive.

Where the combined effects of a reagent and heat are required to be observed, the former
may be added as usual, and the slide placed upon the brass table mentioned at p. xxviii

d

xliv INTRODUCTION.

until the liquid boils, or the requisite amount of heat has been applied, — the object of
course being covered by thin glass. The slide must then be allowed to become perfectly
cold before being placed under the microscope ; otherwise the heat might melt the balsam
with which the lenses of the object-glass are cemented together. The cooling is much
facilitated by placing the slide upon a plate or surface of metal ; we generally use the
foot, or a part of the stand, of the microscope for this purpose.

The effect of a red heat is sometimes very desirable to be tested. This may be accom-
plished by exposing the object, placed upon a strip of platinum foil, a piece of thin glass
or of mica, to the flame of a spirit-lamp. The odour evolved should be noticed. If this
be ammoniacal, or resemble that of burnt horn, the body, if not crystalline, is probably of
animal nature, and certainly contains nitrogen.

If the body consist solely of inorganic matter, or of oxalates, it will not be blackened by
the heat. If it consist partly of inorganic and partly of organic matter, it will be blackened,
and the inorganic matter will be left in the form of an ash. The alteration produced in
the form of the object by the heat should also be noted.

In applying a red heat to a substance upon thin glass, the whole of its moisture must
first be expelled by evaporation ; otherwise the glass will certainly crack, and the experi-
ment be spoiled. The strip of platinum may be held by forceps ; and the thin glass or
mica, upon a curved piece of iron wire. We can here add only a few of the reagents the
action of which it may be most desirable to obtain in determining the nature of a doubtful
body. Further particulars will be given under the heads of the various reagents, prin-
ciples, and tissues, in the body of the work.

1. Solution of caustic potash (especially when heated). — The cell-walls of plants are not
greatly affected ; they retain their primitive form, only becoming somewhat swollen, whilst
animal substances are mostly dissolved ; chitine, however, is unaltered. The solution also
possesses a remarkable power of separating many animal structures into their component
cells, &c. When cold, it separates proteine compounds from fatty matters, £c. It al.so
removes the foreign compounds with which the cellulose of the epidermal structures of
plants is often imbued. Its action has been proposed to distinguish an animal from a
vegetable organism, and will yet probably prove to be of value in this respect.

2. Solution of iodine (in water) dyes most animal and vegetable substances brown ;
renders also lime brown; colours starch, certain cell-walls of vegetables, amyloid, the
amylaceous bodies of the human brain, &c. blue.

3. Sulphuric acid, when added to the external coat or cell-wall of plants (cellulose) dyed
with iodine, renders it blue or purple (PI. 7. figs. 1 c and 3 c). In a few instances, how-
ever, where cellulose exists in animal tissues, the same blue colour is produced ; but in
these there is real animal matter also, recognizable by its appropriate tests. When added
to bile or proteine compounds mixed with solution of sugar, it renders them red (Petten-
kofer's test). If the body contain lime (except already as sulphate), the acicular
crystals of the sulphate (PL 10. fig. 16) are produced.

4. Muriatic acid with heat colours the proteine compounds.

5. Acetic acid brings into view the nuclei of animal cells and tissues, dissolves many
salts, &c.

6. Dilute nitric acid (20 per cent.) coagulates albumen, renders unstriped muscular
fibre-cells very distinct, £c. Strong acid by boiling removes all but the cellulose from
woody fibre.

MEASUREMENT. xlv

7. Mittorfs test-liquid for proteine compounds. (See MILLON'S TEST.)

8. Ether or benzole dissolves fatty and resinous matters, &c.

9. Chromo-sulphuric acid, or a mixture of solution of bichromate of potash and excess
of sulphuric acid, dissolves the intercellular substance of plants, thus isolating beautifully
the wood-cells &c., and developes the starch-rings &c.

10 Ammoniuret of copper^ formed by digesting copper turnings in an open bottle with
solution of ammonia, rapidly dissolves cellulose. It must be used fresh.

11. Dye-tests. — Carmine and ammonia, or the aniline-compounds, Judson's dyes,
magenta, picro-carniine, logwood, chloride of gold, picric acid, &c. are often used as such
(STAINING).

These are perhaps the most common reagents which the experimenter will be called
upon to use. A general plan for the qualitative analysis of substances must be obtained
from works upon chemical analysis. It may be remarked, however, that the qualitative
analysis of portions of a substance too minute to be more than barely discerned by the
naked eye, may be effected by the aid of the microscope. The use of the microscope in
strictly chemical investigations also, cannot be too highly recommended; for it will
frequently throw great light upon the distinction of chemical precipitates of closely
approximative chemical properties.

D. MEASUREMENT.

A knowledge of the size of objects is of the utmost importance, and is frequently of
great assistance in the distinction of one object from another ; for many objects of totally
dissimilar nature present exactly or nearly the same appearances when examined with
differ ent powers. The dimensions should invariably be added to the description of micro-
scopic bodies ; and when figures are grven, the number expressing the linear amplification
of the objects should be placed near them.

Directions for determining the measurement of objects are given under the head
MEASUREMENT . It should always be expressed in fractions of an English inch.

In conclusion, we must remark that the observations given in this Introduction are not
offered as by any means complete. However, we trust they will serve to show that there
are numerous means at command for determining the structure of objects, to indicate
the nature of these means, and that microscopic researches should be earned out upon
something like a definite plan.

MICROSCOPIC ANALYSIS.

The following list of miscellaneous matters, forming an analysis of the second part of
the Introduction, may serve to recall to the observer the most important points to be
looked for, and the means of discovering them.

MICROSCOPIC ANALYSIS. Form : — a, outline; b, rolling over ; c, side xific ; d, end view;
e, angles, goniometer.

xlvi INTRODUCTION.

Colour : — 1, General colour, true colour ; 2, pigment ; a, partial from pigment ; b, general
colour from pigment ; 3, iridescence, thin plates ; air-bubbles, &c., immersion in highly
refractive liquids, action of transmitted and reflected light ; compression ; polarization, &c.

Surface: — Reflected light] projections; cilia, margin, iodine, desiccation, fine particles ;
hairs, crystals — upon or beneath the surface ; tubercles, ridges, folds, side view ; effects
of altered focus ; fracture ; foramina, polariscope ; illusory lines, diffraction ; depressions,
circular, angular ; furrows ; tubules ; cells ; oblique light, stops in condenser.

Internal structure and contents : — Homogeneous ; cell-wall, endosmosis, evosmosis,
chloride of calcium ; adherence ; margin, crushing, molecular motion ; granules, nucleus —
central, exceutric; reagents, acetic acid; nucleolus, vacuoles.

HISTOLOGUCAL ANALYSIS. — Reagents ; maceration, development.

MICRO-CHEMICAL ANALYSIS. — Washing', heat; red heat, odour, ash; reagents, contact
with reagents ; potash, ammoniuret of copper, iodine, sulphuric, chromo-sulphuric, muriatic,
nitric, acetic acids ; Millon's test ; sulphuric acid and syrup ; sulphuric acid and iodine ;
ether or benzole, fyc. ; dyes.

MEASUREMENT. — In fractions of an English inch (not line nor foreign measures).

BIBLIOGRAPHY. — MICROSCOPKS, APPARATUS, and OBSERVATION. Quekett, Microscope,
1853; Brewster, Treat, on the Microscope; Ross, 'Microscope,' Penny Cyclopcedia ; Du-
jardin, Observateur ; Mandl, Trait6 prat, du Microscope, 1839; Chevalier, Traite d. Micr.
Sec. ; Tulk and Henfrey, Anat. Manip. ; Mohl, Micrographia, 1846 ; H. Schacht, Das
Mikroskop (Currie, 1853) ; Harting, Het Microscoop (and the German translation, Das
Mikroskop, 1866) ; Carpenter, The Microsoope, 1881 ; Goring and Pritchard, Microsc.
Cabinet, 1832; Hannover, The Microscope (transl. by Goodsir), 1853; Heller, Dasdioptrische
Mikr., 1856 ; Journal of the Microscop. Soc. of London ; Monthly Microsc. Journ. (to 1877) ;
Quart. Journal of Microsc. Science (passim) ; Reinicke, Beitrag. z. Mikrosk., 1863 ; R.
Beck, Treatise on Achromatic Microscopes, 1865 j Frey, Das Mikroskop $c., 1881 ; Nageli
u. Schwendener, Das Mikroskop (Mathematics), 1877 ; Reinisch, D. Mikr., 1867 ;
Wiesner, Einleitung $c., 1867 ; Hager, Das Mikrosk., 1876 ; Dippel, Das Mik. fyc.t 1867-
71 ; Chevalier, EEtudiant Micrographe, 1872 ; Robin, Le Mic., 1877 ; Wythe, Micro-
scopist, 1877; Duval and Lerebouillet, Man. (cKnique) d. Micr. 1880 ; Pelletan, Mic., 1880 ;
Beauregard and Galippe, Microgr., 1880 ; Thanhoffer, D. Mik., 1880 ; Beale, How to Work
8fc., 1880 (in which every kind of apparatus is described and figured) ; and the Journal de
Micrographie and Zeitschrift f. Mikroskopie.

MICROGRAPHIC DICTIONARY.

ABERRATION.— The deviation of the
rays of light from the true focus of a lens or
curved mirror, in consequence of which
they do not unite at a single point, but
form an indistinct or coloured image of an
object. It arises from two causes : the
form of the lens or mirror, when it is called
spherical aberration ; and the different re-
frangibility of the rays of light, when it is
called chromatic aberration.

ABROTHAL'LUS, Notaris and Tulasne.
— A genus of Lichens, Fam. Lichenacei,
remarkable for their parasitic habit and the
absence of a thallus. The species are now
referred to LECIDEA.

A. Smithii (Welwitschii and microsper-
mus) = L. parmeliarum.

A. oxysporus = L. oxysporus.

A. inquinans = L. inquinans.

BIBLIOGRAPHY. Lindsay, Brit.Lich. 31 1 ;
Tulasne, Ann. So. Nat., Bot. xvii. p. 112,
1852 ; De Notaris, Mem. JR. Acad. Sc . Turin,
x. p. 351, 1859 j Berkeley, Cryp. Sot. 405 ;
Leighton, Lichen-Flora, p. 384, 1879.

AC ALE 'PILE (Medusa).— An order of
Ccelenterata, commonly known as Sea-net-
tles, on account of their producing urtica-
tion when touched ; or Jelly-fishes, or Sea-
blubbers, from their gelatinous consistence.

They consist of a transparent, floating
and free, discoid or spheroid body (hydro-
sorna), often shaped like an umbrella ; and
vary in size from a mere speck to a yard in
diameter. Margin of the disk furnished
with filiform tentacles, cirri, &c. The
organs are radiate around a longitudinal
axis, occupied by a central peduncle or
stalk (manubrium), at the bottom of which
is the mouth. The disposition of the parts
is generally quaternary.

The cutaneous surface of the body, or
ectoderm, is covered with a very delicate
epidermis (PI. 49. fig. 2). Cilia exist on
various parts of the body, especially the

Thaumantias hemisphaerica, magnified 2 diameters.

arms, tentacles, cirri, &c ; upon which also
peculiar stinging organs and organs of ad-
hesion occur. In those species which are
notorious for their urticating powers, these
organs are also situated in aggregations be-
neath the epidermis of the body. The
stinging organs, or nematocysts, usually form
oval capsules, in which a spirally coiled
filament is enclosed (PI. 49. fig. 3 «, &) ;
this flies out on the slightest touch, with
the capsule to which it is attached, from the
irritated part of the skin (PI. 49. fig. 3 c).
In some Acalephse these stinging organs
are replaced by oval capsules from which a
rigid bristle projects (PI. 49. fig. 4). These
do not produce urtication, but enable the
animal to adhere to other bodies. Near
the surface of the body and between the
cells composing its substance, pigment-cells
frequently occur, some of which are isolated,

B

ACALEPELE.

ACALEPH.E.

others aggregated into groups. The paler
and more delicate colours are said to avi>ti
in some instances from pigment uniformly
dissolved in the substance of the body ; it
is most probable, however, that they arise
from iridescence.

Muscular system forming long, thin, reti-
cular fibres and bundles, almost everywhere
pervading the contractile substance of the
body.

The floating and locomotion of these ani-
mals are often aided by larger or smaller
cavities filled with air.

The nervous system consists of a ring
following the margin of the disk, with
ganglionic expansions at intervals, giving
off branches to the tentacles and the radial
canals.

The organs of sense consist of tubercular
or spathulate bodies situated near the mar-
gin of the body or at the base of the ten-
tacles, and connected with adjoining ganglia.
Some of these are regarded as organs of
vision (ocelli) j and consist essentially of a
membranous capsule containing a clear
liquid with crystals of carbonate of lime,
and sometimes a red or black pigment
(PL 49. fig. 5 ff). Those which contain no
pigment have been considered to be of
auditory function, and the crystalline bodies
otolithes. Some of them are protected by
an overhanging fold of membrane ; hence
the distinction of covered- and naked- eyed
Medusa ; but the latter are now regarded as
the sexual zooids or gonophores of the
Hydroida (THATJMANTIAS).

The digestive cavity, which is situated in
the middle of the body, is lined with cili-
ated epithelium and furnished with distinct
walls (endoderm), which are directly con-
tinuous with the general parenchyma'of the
body, so that there is no abdominal cavity.
The mouth is either single and central, or
multiple. In the former case, it is situated
at the end of the peduncle, in the middle of
the under side, and leads into a stomach,
which is frequently furnished with caecal
appendages. When several oral apertures
are present, either several cesophageal canals
conduct the nutriment through the arms,
in which the oral apertures are placed, to a
central stomach, or each separate mouth
is connected with a distinct tubular sto-
mach. A distinct hepjatic organ has not
yet been found. Ray Lankester describes
the inception of natural food-materials in
the cells of the endoderm.

Gastrovascular system. A number of

vessel-like canals run from the stomach or
central cavity throughout the body, the
principal branches forming rays from the
centre to the margin, communicating finally
with a circular vessel traversing its circum-
ference (PI. 49. fig. 5 d). These are also
lined with cilia, and contain both the loud
and water. But there is no regular circu-
lation.

The Acalephae are propagated by the for-
mation of ova, and according to the plan of
alternation of generations. They are either
hermaphrodite or unisexual.

The reproductive organs of the two sexes
are often so similar in colour, external form,
and arrangement, that they might ca-ily
be mistaken for each other, without exami-
nation of their contents. They form either
utricular or strap-shaped stripes, placed at
various parts of the body, often near the
rays of the gastrovascular system. In the
former case, the spermatic fiuid and the ova
are evacuated through distinct excretory
ducts ; in the latter, the spermatozoa and
ova escaping from the strap-shaped testis
or ovary, pass directly outwards, or into
capacious cavities opening externally by
wide orifices. The ova are round, and sur-
rounded by a single very delicate capsule ;
and the germinal vesicle with its simple
germinal spot is visible through the whitish,
violet, or yellow yolks. The spermatozoa
move rapidly in, and are unaffected by
water j they are linear, or one end is
rounded, the other prolonged into a capil-
lary appendage (PI. 49. fig. 5*).

The developmental metamorphosis of
some of the Acalephae is very remarkable.
When the ordinary process of segmentation
pf the entire yolk is completed, the ova be-
come converted into ovate infusoria-like
embryos or planulae (PL 49. fig. 6), which
revolve upon their longitudinal axis by
means of ciliated epidermis, and swim about
like species of Leucophrys or Bursaria.
After a time, they become fixed at the
anterior extremity to some bcdy ; arms
then shoot out from the unattached ex-
tremity, between which the mouth of the
polype-like animal (Hydra-tuba state) is
developed (PL 49. figs. 7 & 8). At this
stage of development, the larvae multiply by
the formation of gemmae (PL 49. tig. 9 «),
and offsets or stolons (PL 49. fig. 9 b) ; and
ultimately each undergoes transverse di-
vision, which takes place as follows : — the
larvae grow in length, and the body be-
comes constricted into several segments

ACANTHACE.E.

ACANTHOMETRINA.

(PI. 49. fig. 10), from each of which eight
bipartite processes shoot out in a whorl
(Strobila-state) . The segments of the body
then separate from each other seriatim, from
before backwards, swim about with eight
rays (PI. 49. fig. 11), and at last become
gradually developed into perfect Medusas.
Many of the Medusae are phosphorescent,
and render the sea luminous.

Gegenbaur divided a Thaumantias into a
hundred pieces, and found that each piece,
provided it contained a portion of the mar-
gin of the umbrella, grew into a perfect
small Medusa.

Many of the organisms formerly con-
sidered Medusa are now regarded as the
Medusoid buds or gonozoids of the Hy-
droida. See THAUMANTIAS.

A small Medusa, with 2 names : Craspeda-
custes SowerbyiandLimnocodium Victoria ,has
been found in the tropical fresh-water lily-
tank at the London Royal Botanic Gardens.
This ought to be the Medusoid gonophore
of a hydroid zoophyte !

BIBL. Eschscholtz, Syst. d. Acal. Berlin,
1829; Will, Hoi-ce Tergest. $c., 1844;
Ehrenberg, Abhandl. d. Berl. Akad. 1835 j
Art. Acal., Tcdd's Cycl (R.- Jones) ; Sie-
bold, Lehr. d. Vergl. An. ; Huxley, Inver-
tebrata ; Lesson, Suites a Buffon (Zooph.
Acalephes) ; Wagner, Icon. Zootom. ; Ge-
genbaur, Vergl. Anat. 1878 ; Gosse, Mar.
Zool. ; Forbes, Nak.-eyed Medusce (Ray
Soc.) ; Kolliker, Icon. Histol. 1865 ; Haeckel,
Syst. d. Medus., 1879 ; Romanes, Phil. Tr.
1876, p. 269 (Muse, syst.}; Nicholson,
Zool., 1878; Pascoe, Zool. Class., 1880;
Kowalewsky, Ann. Nat. Hist. 1867, xx. 228;
R. Lankester, Qu. Micr. Jn. 1881, p. 119.

ACANTHA'CILE.— The seeds of many
genera of this family are clothed with hairs
composed of hygroscopic cells, containing
unreliable spiral fibres or detached rings.
Among these are Acantliodium spicatum, De-
lile, Blepharis, and Ruellia formosa. Other
species and genera have the hygroscopic cells
destitute of internal fibre, as Ruellia littora-
lis, Phaylopsis glutinosa, Barleria noctiflora,
Lepidagathis, 8fc. Further particulars re-
specting the hygroscopic cells will be found
under CELL-MEMBRANE and SPIRAL STRUC-
TURES. See also ACANTHODIUM and
RUELLIA, and, for a similar phenomenon in
other families, COLLOMIA, COBJEA, SALVIA.

BIBL. Kippist, Linn. Trans, xix. p. 65.

ACANTHOCYS'TIS, Carter.— A genus
of Rhizopocla, apparently referable to the
Actinophryina.

Char. Rounded, green, with movealle
radiating spines and pseudopodia. Body
flexible, covered with minute fusiform
curved spicula ; spines straight, hollow,
bifid, discoid at base.

A. turfacea (PI. 51. fig. 9). Found in
heath-bog water; diam. of body JTT"-

BIBL. Carter, Ann. N. Hist. 18(33, xii.
p. 263 ; Hertwig, Jen. Zeitsch. (Qu. Mic. Jn.
1878, xviii. p. 205).

ACANTHO'DIUM (Flowering Plants,
fam. Acanthacea). — Kippist first described
the curious hairs upon the seed of Acantho-
dium spicatum, Delile (PI. 28. fig. 24). The
entire surface of the seed is clothed with
hairs of whitish colour, appressed and closely
adherent in the dry state, being apparently
glued together at their extremities. When
placed in water, the hairs are set free and
spread out on all sides ; they are then seen
to consist of clusters of from five to twenty
spiral cells firmly coherent below, but free
above and separating from the cluster at
different heights, expanding in all directions
like plumes, and forming a very beautiful
microscopic object. The free portions of
the cells elongate so as to separate the coils
of one, two, or occasionally three internal
spiral fibres, which are sometimes branched
and not unfrequently broken up into rings ;
at the lower part of the cells the turns of
the spiral are connected by perpendicular pro-
cesses so as to convert the spiral into a reticu-
lated structure. See SPIRAL STRUCTURES.

BIBL. Linn. Trans, xix. p. 65.

AC ANTHOME'TRA, Mull.— A genus of
ACANTHOMETRINA.

ACANTHOMETRI'NA.— A family of
Radiolarian Rhizopoda.

Char. Body minute, spherical, capsular ;
traversed by numerous elongate, mostly
angular and hollow siliceous spines, which
meet in the centre. Between the spines,
pseudopodia radiate from the body (PI. 51.
fig. 10), as in Actinophrys. Marine.

The body contains yellow globules, and
is sometimes covered with small spicules;
and it is enveloped by a softer cortical sar-
ccdic mass.

The Acanthometrina, with the Polycys-
tina, have been rearranged by Hackel, in
his splendidly illustrated monograph, into
68 genera and 150 species.

They are found recent on the surface and
at the bottom of the sea, in the Mediterra-
nean, the Adriatic, and the North Sea.

They form beautiful microscopic objects.
See RADIOLARIA.

B 2

ACANTIIOPUS 4 ]

BIBL. Miiller, Ber. d, Berl. Ak. 1855,
p. 248 ; id. Abh. d. Berl. Ak. 1858, p. 1 ;
Hfickel, Radiolar., 1862; Claparede and
Lachmann, In fits. p. 59.

ACAN'THOPUS, Vernet.— A genus of
Entomostraca, Ord. Ostracoda, fam. Cythe-
ridse. Lake of Geneva.

BIBL. Bibl. Univ. 1877 (Jn. Mic. Soc.
1878, p. 80).

ACA'REA. — A family of Arachnida, be-
longing to the order Acarina (ARACH-

ACARUS.

These animals are commonly called mites ;
and every one is familiar with them as oc-
curring in cheese, sugar, flour, &c. Some
also occur upon the skin of man and
animals, producing the itch and the
mange.

The parts of the mouth and the legs, upon
which the characters are usually founded,
may be best made out by crushing the ani-
mill upon a slide with a thin glass cover,
and washing away the exuding substance
with water, as directed in the Article PRE-
PARATION ; sometimes hot solution of pot-
ash is requisite, with the subsequent addi-
tion of acetic acid and further washing.
When afterwards dried and immersed in
Canada balsam, the various parts become
beautifully distinct, and may be perma-
nently preserved.

Acarus (Tyroylyph'us), Body with a
transverse furrow between the 2nd and 3rd
pairs of legs ; legs nearly equal, all perfect,
and terminated by a membranous sucker or
claws, or both ; palpi adherent to the la-
bium (or lip).

Hypodera*. Body very long, legs very
short, and the 2 anterior and posterior pairs
far apart; parasitic beneath the skins of
birds.

Hypopus. Front pair of legs mostly
largely developed ; posterior almost atro-
phied. Parasitic on animals and plants.

Trichodactylus. Rostrum (beak) short,
with minute bristles ; 4th pair of legs longer
than the rest, without claws, and terminated
by a very long bristle, the rest with 2 claws.
(Parasitic on Bees.)

Psoroptes. Body soft, depressed, spiny
beneath and at the base of the legs ; poste-
rior pair of legs small and rudimentary, the
rest with a claw and sucker ; body termi-
nated by two bristly projections. (Para-
sitic on the Horse.)

Sar copies. Body soft, transversely wrin-
kled, and with dorsal papillae ; anterior
2 pairs of legs with suckers, posterior ter-

minated by a long bristle, and without
suckers. (Parasitic.)

Demodex. Body elongate ; cephalothorax
distinct from the ringed abdomen : legs
terminated by 4 or 5 very minute claws.

ACAREL'LA, Kent. — A genus of In-
fusoria ; near Halteria. Kent, Man. Inf.
1880, p. 214.

AOAREL'LUS, Westwood.— A sup-
posed genus of Acarina. See HYPOPUS and
PHYTOPTIDA.

They seem to consist of larvae of Phy-
topti or species of Hypopus.

BIBL. Westwood, Proc. Entom. Soc. 18C4,
p. 30, and 1870, p. 30 ; Tatem, Mon. Mic. Jn.
1872, viii. p. 263 ; Murray, Econ. Entmnol.
p. 246; Mclntire, M. Mic. Jn. 1874, xi. p. 1.

AOARI'NA. — An order of ARACHNIDA.

AC'ARUS, Linn. (Tyroglyphus). — A
genus of Arachnida, of the Order Acarina,
and family Acarea (see ARACHNIDA and
ACAREA).

The palpi adherent to the labium, the
perfect legs, and the transverse furrow dis-
tinguish the genus.

Ac. domesticus, or siro (PI. 6. fig. 1), the
common Cheese-mite. Body oval, soft,
whitish, turgid and furnished with long
feathery hairs (6). The transverse furrow
(c) occurs at about the anterior fourth of
the body ; and another is seen between the
head and the part corresponding to the
thorax. The head is susceptible of elevation
and depression. In its natural state it
appears conical (d}, and is furnished with
two large mandibles ; these consist of a soft
retractile basal joint (e), and a second, di-
lated, non-retractile joint (/) resembling
the fixed claw of a lobster, and a moveable

Eiece (/*) working against the latter. The
ist two pieces are toothed where in contact
with each other. These mandibles can be
advanced separately or together, and be
separated or approximated. When in a
state of repose, they form as it were a roof
above the labium. The labium (g) is quadri-
lateral, elongated, notched at the end, thin
anteriorly and in the middle, and consolida-
ted laterally with the palpi, which are 4- or
5-jointed (h h). The legs are reddish, in-
serted in two separate groups, but not very
far distant as in Sar copies. The anterior
pair of legs are remarkable for their size in
the male, which is smaller and more active
than the female ; the third pair are the
shortest and smallest ; the third joint or
femur is larger and longer than those next
it; the sixth joint is long and thin; the

ACARUS.

ACARUS.

seventh joint is furnished with a cordiform
membranous caruncle, and a single simple
claw or hook ; rostrum and legs reddish.

This species is viviparous and oviparous,
and the eggs very numerous. The larvae
are hexapod.

These mites are very abundant upon old
cheese, the powder of which entirely consists
of them, with their eggs and excrement.

Ac. lonyior. Body and hairs longer.
Found upon Gruyere and Dutch cheese
(PI. 6. fig. 2). This is the so-called Ac.
Crossii.

Ac. Siculus. With short legs. Found in
powdered Cantharides. Megnin, p. 143 ;
Murray, p. 274.

Ac. mycophagus. Body long. Found
on mushrooms. Megnin, p. 143.

Ac. entomophayus. Found in collections
of insects, of which it devours the body.
Megnin, p. 143 j Murray, p. 263.

Ac. mains. On apple-trees in N. America.
Murray, p. 275.

Ac. translucens. On coffee-plants in
Ceylon. Murray, p. 275.

Ac. bicaudatus. Abdomen furnished with
two pedif orm tubercles, beneath the base of
each of which is a stigma. Found upon
the feathers of an ostrich.

Ac.fari'na, same SisA.domesticus. Found
in bad flour. DeGeer, Mem. vii. p. 97, pi.
15. fig. 15. (Ac.feculce, found by myriads
in potatoes. Guerin-Meneville, Ann. N.
Hist. 1867, xix. p. 71.)

Rhizoylyphus (Claparede). Tarsi with
claws, but no suckers. Vegetable feeders.

R. echinopus. In the bulbs of hyacinths.
Murray, p. 257, fig. ; Megnin, p. 144, fig.
49.

R. phylloxera. On vine-roots. Murray,
p. 258.

R. Robinii. On potatoes, dahlia, and
hyacinths. Murray, p. 259.

R. rostroserratus. On decaying mush-
rooms. Murray, p. 260.

Serrator (Megnin). Mandibles strongly
serrate ; a hook, but no caruncle.

S. amphibius. In decomposing mush-
rooms. Megnin, p. 144, fig. 50.

Ac. Dysenteric. Nyander, Amcenit. Acad.
v. p. 97 ; Linn. Grnel. p. 2929. Found in
the dejections of dysentery; also in old
casks.

Ac. passerinus. Found upon young
birds. DeGeer, vol. vii. 139. Ac. chelopus,
Herm. Mem. Apteral, p. 82, pi. 3. fig. 7.

Ac. (Carpoglyphus) passularum. With
two very long buccal bristles; lives upon

dried figs, and other saccharine fruits.
He ring, Nova Acta, xviii. p. 618, pi. 45. f . 14,
15 ; Megnin, p. 141.

Glyciphayus (Hering). Body soft, not
divided into two parts by a transverse line
or furrow, but with a dorsal depression,
and an anal projection ; legs perfect, with
acetabula ; hairs feathery.

A. (Gl.) prunorum. Found on dried
plums ; produces the grocer's itch. Hering,
Nova Acta, xviii. p. 619. pi. 45. f. 16, 17 ;
Murray, p. 278, fig.

A. (Gl.) hippopodos. Body as broad as
long, very acute anteriorly, entirely covered
with short hairs j a minute projection at
the end of the abdomen. On ulcers of
horses' feet. Hering, Nov. Act. xviii. p. 607 ;
Murray, p. 279, fig. An undescribed
Acarus has also been mentioned as occurring
upon the feet of sheep affected with the
canker. Grognier, Zool. veter. p. 233.

A. (Gl.) hericius. Found on weeping
ulcers of elms. Robin, Journ. d. VAnat.
1868, p. 603.

A. (Gl.) cursor. Found in the feathers
of the owl and in the cavities of the bones
of skeletons. The hairs are jointed. Ger-
vais, Ann. Sc. Nat. 2 ser. xv. p. 18, pi. 2.
f. 5 a ; Murray, p. 278, fig.

A. (Gl.) spinipes. Like G. cursor, but
smaller ; the anal appendage short. Frem.
& Rob. Jn. Anat. 1867 ; Murray, p. 281,

%•

A. (Gl.) balcenamm. On whales. Murray,
p. 282, fig.

G. plmniger. With strongly feathery
hairs. In cellar-dust, stables, &c. Murray,
p. 283, fig. A beautiful object.

G. palmifer. Smaller than the cheese
mite ; hairs leaf-like ; body granular.
Murray, p. 284, figs. Found with the
last.

A. (Gl.} (Sar copies) palwnbinus. On the
pigeon. Koch, I. c. fasc. 5. pi. 12 ; Robert-
son, Qu. Micr. Jn. 1866, p. 201.

Some other species have been insuffici-
ently examined : —

Ac. avicularum, DeGeer, Mem. vii. 106.
pi. 6. fig. 9. Louse of the grouse. Lyonet,
Mem. Mus. xviii. 281. pi. 15. f. 16.

Ac. marilce, Gervais, Diet. Sc. Nat. Suppl.
i. 45.

Ac.favorum. Found in old honeycombs.
Herm. Mem. Apterol. p. 86.

Ac. fungi, Herm. /. c.

Myobia (Heyden). Body elongate, rnauy-
lobed ; rostrum styliform.

M. musculinus, Schranck, p. 501, pi. 1.

ACAULON.

ACII1TA.

f. 5. Sarcoptes muse., Koch, Crust. $c.
fasc. 5. pi. 13 ; On the mouse, Murray, p. 315.

Hypopus. See HYPOPUS.

A destructive disease in the sugar-cane is
caused in various parts of the world by a
minute red Acarus, which swarms round
the stem.

BIBL. Duges, Ann. d. Sc. Nat. 2 se"r. ii.
p. 40 ; Koch, Deutschl. Crust. ; Walckenaer,
Aptcres, 3 (Gervais) ; Fumouze and Robin,
Jmirn. d. VAnat. 1867, 505, 561 ; Boisduval,
ISEntomol. horticole, p. 76; Mic. Soc.
Jn. 1880,^/1/0. dev. p. 249; Murray, J%.jBi&
1880 ; Megnin, Parasites, 1880.

AOAU'LON, C. Miiller.— A genus of
Phascaceae (Acrocarpous Mosses), taken as
a section of Phascum by Wilson. A. muti-
cum is common on moist banks.

BIBL. Miiller, Synops. Muse. i. p. 21 ;
Wilson, Bryol. Brit. p. 29.

ACEPH'ALpOYSTS.— A term used to
denote certain simple sacs filled with a trans-
parent liquid, found in the bodies of ani-
mals, and usually known as Hydatids by
pathologists. They were formerly regarded
as distinct parasitic animals ; but recent
observations show that they often consist of
the cysts or larval forms of cestoid Entozoa.
The cysts in many cases contain at first
only an amorphous substance or a liquid.
At a later period their real nature is deter-
mined by the presence of the included
Echinococcus — head and hooks. The sacs
or vesicles are oval or spherical, and vary
in size from a pin's to a child's head. The
walls of the sacs vary in thickness and
transparence. They present no appearance
of either head or body. In the larger cysts
the walls are distinctly laminated. They
exhibit no fibrous structure, but appear
composed of a homogeneous substance
closely resembling albumen in properties.
Two species have been distinguished : —

A. endogena (socialis vel proliferd), the
pill-box Hydatid of Hunter. This is met
with in the liver, kidney, ovary, testis, and
cavity of the abdomen. When developed
in the substance of an organ, it is always
enveloped by areolar tissue. The secondary
cysts are detached from the inner surface of
the parent.

A. exogena : in this the progeny is de-
veloped from the outer surface ; found in
the ox and other dometic animals.

In the examination of cysts supposed to
be hydatids, careful search should be made
for the hooks of Echinococcus or Cysticercus
which can frequently be found when no

further remains of the body are distingui .-li-
able. The hooks are figured in 1*1. 21.
fig. 16. See ENTOZOA and ECHINOCOC-
CUS.

ACERVCJLI'NA, Schultze.— Under this
name Schultze, in 1854, grouped as a genus
some of the adherent varieties of Planorlu-
lina variabilis, D'Orb., that have an irregular
growth, with heaped chambers. They are
found in warm seas, attached to algae and
other bodies. The word "acervuline" is
applied to any such ' wildly aggregated
growth in Foraminifera.

BIBL. Schultze, Organism. Polythal. 67 ;
Carpenter, Forum. 209.

ACETIC ACID.— This is the well-
known acid of vinegar.

It occurs in the juice of the flesh of ani-
mals ; sometimes in the stomach in indiges-
tion ; also in the human blood after the use
of alcoholic liquors, and in that of animals
whose food has been soaked in spirit. It is
also a common product of the decomposition
of vegetable substances, both by fermenta-
tion, and in distillation, as well as a com-
ponent of the natural plants, mostly com-
bined with lime or potash ; it is also a rare
constituent of some mineral waters.

The only salt of this acid requiring men-
tion is the acetate of copper (neutral), which
is made' by dissolving common verdigris in
excess of dilute acetic acid, filtering and
crystallizing upon the slides. The crystals,
when mounted in Canada balsam, exhibit
well the phenomena of dichroisin. PL '39.
fig. 2.

Acetic acid is one of the most common
and valuable micro-chemical reagents. It
is particularly useful on account of its action
upon animal cells in general, rendering the
coil-walls transparent and the nuclei more
distinct. The ordinary strong acid (sp. gr.
1044) should be used.

ACETINOP'SIS, Kent —A genus of Iii-
fusoria, family Ophryodendridae.

BIBL. Kent, Man. Infus. 1880.

ACHARAD'RIA, Wright.— A genus of
11 yilroid Zoophytes.

A. larynx resembles in habit Tulmlaria
larynx ; polypes orange. Marine ; on stones.

BIBL. Str. Wright, Qu. Mic. Jn. 1865,
iii. p. 50 ; Hincks, 'Brit. Zoophyt. p. 133.

ACHE'TA. — A genus of Orthopterous in-
sects, one species of which, A. domestica, the
house-cricket, is familiar to every one. The
general structure of this insect agrees so
closely with that of Blatta orientalis, the
common cockroach or black beetle, which is

ACHLYA.

ACHLYA.

described at some length, that it requires no
special notice here. (See BLATTA.) Some
parts of the internal structure of the cricket
are very beautiful, as the tongue (PL 33.
fig. 23), the gizzard (PI. 34. fig. 1), and the
ear in the fore legs (PL 34. fig. 76). These,
as also the curious mechanism by which the
chirping noise of the male is produced, are
described under INSECTS.

ACH'LYA, Nees (&?/>ro/e*7w?#,Kutzing).
— Remarkable microscopic plants,sometimes
referred to the Al^se, but more properly
belonging to Fungi. Cienkowski has re-
cently confirmed the idea formerly enter-
tained, that Aclilya is an aquatic form of
the Mucorinous Fungus called SPORENDO-
NEMA Muscce (Empusa MUSC&, Oohn), the
common fly-fungus. Cohn and Al. Braun
deny the identity, while Berkeley thinks
AcJilya may be an aquatic form of Botrytis
Sassiana. They are found growing para-
sitically upon the bodies of dead flies lying
in water, also upon fish — as salmon, salmon-
eggs, frogs, &c., and in some cases upon de-
caying plants. To the naked eye they ap-
pear like colourless minutely filamentous
tufts, adherent to such objects, forming a
kind of gelatinous cloud more or less en-
veloping them. When placed beneath the
microscope, the tufts are seen to consist of
long, colourless, tubular filaments, spreading
out in all directions, with or without lateral
branches; these erect filaments arise from
a kind of mycelium of ramified filaments
lying upon the object upon which the plant
grows. The erect filaments are devoid of
septa, narrowed upwards, and vary in thick-
ness, being usually of smallest diameter in
those cases where they are closely crowded;
the ordinary thickness varies from 1-1000 to
1-350 of an inch. The tubes contain a colour-
less slightly granular protoplasm, which
is denser on the walls ; and these sometimes
exhibit an irregular spiral arrangement of
the granules ; the granules are seen to move
slowly in anastomosing currents running in
various directions, exhibiting, that is, the
well-known phenomenon of the circulation
of cell-contents, such as is met with in the
hairs of Tradescantia, &c. The walls of the
tubes are coloured blue by iodine and sul-
phuric acid, therefore consist of cellulose ;
the contents are nitrogenous, taking a bright
yellowish brown with iodine ; no trace of
starch or chlorophyll can be detected in the
cell-contents in this stage, whence these
plants are regarded by some authors as
Jungi ; but, as mentioned hereafter, Prings-

heim states that their ripe spores do con-
tain starch.

Kiitzing describes a number of species of
this genus, tinder the name of Saprolegnia,
while a recent observer, Pringsheim, regards
them ah1 as forms produced by varying ex-
ternal conditions. A. de Bary separates
AcJilya prolifera, Nees, from Saproleynia
ferax, Kiitzing, referring to the former the
Saprolegnia ferax of Cams and the Sapro-
legnia capitulifera of Alex. Braun, to the
latter the Aclilya prolifera of Cams, and,
doubtfully, the S. molluscorum of Nees and
Gruithuisen. The distinction between these
is said to lie in the details of the formation
and emission of the active gonidia or zoo-
spores; but we cannot make out satisfactory
differences.

The following details respecting the for-
mation of the active gonidia and the resting
spores are given at length on account of
their well illustrating modifications of free-
cell formation. In about thirty-six hours
after the appearance of a specimen on any
body, the apices of the erect filaments
exhibit remarkable changes. The granular
protoplasm, which at first is equally dif-
fused throughout the tube, only densest
where it lies on the wall, increases in quan-
tity and " travels up " into the end of the
tube, becoming accumulated there, giving
it a brownish colour and at the same time
causing its distention, so that the upper part
of the tube acquires a clavate form, ronnded
off above. A sharp line of demarcation is
soon formed by the division of the primor-
dial utricle, followed by the production of a
septum, which shuts off this clavate joint as
the sporange ; and a little projecting pouch
or beak is developed at the summit, or
sometimes a little below this on one side.
The contents,becoming still more condensed,
again apply themselves as a thick invest-
ment on the wall, leaving a lighter space
in the middle of the cavity. Inequalities, cr
nodular protuberances, are soon observable
in this layer ; and it speedily becomes broken
up into numerous little isolated portions,
individualization of these commencing at
the summit of the sporange and becoming
completed gradually from above downwards.
The end-cell is now a clavate sporange filled
with numerous polyhedral or globular new
"primordial cells," in the development of
which from the contents of the general
parent-cell no trace of nuclei or " special
parent-cells " can be detected ; their size is
about 1-2700 of an inch; and they have

ACHLYA.

ACHLYA.

clearly defined outlines, but are still con-
nected together by a gelatinous substance in
which they are completely imbedded. These
secondary cells then become retracted from
the walls, and accumulate in a dense, rather
confused looking mass in the centre of the
sporange j endosmose of water through the
now bare cellulose wall of the sporange
seems to exert a pressure upon them,and also
on the wall itself, which finally bursts at the
process or beak mentioned above, and the
secondary cells nearest the opening are shot
out with some force, the rest following, but
gradually more quietly. There is no inde-
pendent motion of the contents, or jerking
of the secondary cells, before this emission
of the latter j on the contrary, while in the
Fig. 1*.

Achlya prolifera, discharging its zoospores ; the lower
zoospores treated with iodine ; magnified 400 diameters.

sporange, they adhere so closely that their
shape is scarcely distinguishable, and it is
only when the greater portion have escaped
that it is perceived that the pressure had
caused them to assume a spindle-shape. As
the emission of the secondary cells goes on,
those escaping first are only removed so far

as to make room for their successors, and
th<' \vhole remain adherent together as a
globular mass or " capitulum " seated on the
apex of the sporange ; they reassume, more
or less completely, the spherical form, by
degrees, after they have escaped from the
sporange : those which can expand freely
become globular; those pressed upon by their
fellows become polyhedral. At the time
of emission, these secondary cells exhibit a
double line at the circumference, which
seems to indicate the thickness of the pri-
mordial utricle. Soon after the expulsion
another delicate line is detected external to
these ; and this indicates a newly produced
envelope, which becomes thicker with ;i-v,
and after a certain time can be [coloured
blue by sulphuric acid and iodine, which
demonstrates its composition of cellulose.
Application of a strong acid is necessary for
this purpose.

The globular head of secondary cells
remains for two or three hours attached
upon the summit of the empty, colourless
sporange. Then these minute cells emit
their contents by a lateral orifice, giving
origin, each of them, to a zoospore or active
gonidium. Neither the motion nor the
appearance of cilia follows the expulsion im-
mediately, but takes place after the gouidia
have increased somewhat in size and ac-
quired an ovate form. The duration of the
motion lasts from a few seconds to a few
minutes, after which the gonidium sinks to
rest and begins to germinate. The gonidia
possess no cellulose membrane while in
motion, but acquire one when they come to
rest and germinate. The cilia are two, and
arise from the point which first emerged
from the parent vesicle, and which at all
periods exhibited a lighter tint, indicating
a vacuole in the protoplasmic mass. If
the expulsion of the gonidia is prevented
(as occurs sometimes when the plant is kept
under the pressure of a glass slide, in too
little wrater, in microscopic investigation
of it), the gonidia germinate within their
cell-membranes, which, instead of dis-
charging active zoospores, emit germinating
prolongations, just like those issuing from
the single germinating gonidia. These spread
out here in all directions from the globular
still seated on the end of the

sporange.

During the formation of these sporanges
and the gonidia, after the septum has been
completed, the tube sends out lateral
branches from just below it, which some-

ACHLYA.

ACHNANTHES,

times equal tlie sporange in length by the
time the latter discharges its contents j then
this branch becomes developed as a spo-
range, either at its summit or in its whole
length, or, when the branch is very short,
the portion of the main tube below the first
septum becomes a sporange. Sporanges of
a- third rank may succeed to those of the
second rank, and so on, until the plant has
exhausted the supply of food at its service.
In another form the active gonidia are pro-
duced at once in the sporanges, without the
intervention of secondary cells ; and then
they begin to move even before leaving the
parent sac.

Aclilya prolifera also produces, though
more rarely, globular or spindle-shaped spo-
ranges, either terminal or borne on special
short lateral branches, in which are deve-
loped resting spores, characterized by a
larger size, double cell-membrane, and by
the absence of the cilia and consequent
motion. The mode of their development is
similar to that of the active gonidia ; but
they are much fewer in number, sometimes
as many as twenty, sometimes only four,
three, two, or even one being present in a
sporange. When a number occur in a
spindle-shaped sporange, they are ranged in
two rows, alternately, so that each is par-
tially interposed between its two opposite
neighbours. Their diameter varies from
1-1250 to 1-750 of an inch, the colour brown-
ish, displaying numerous oil-drops in the
granular contents when mature. The spo-
ranges producing them display a number of
round orifices when the spores are ripe ; but
the spores appear to escape by the decay of
the walls. These resting spores may remain
unchanged in water for a long time when no
suitable nidus exists, but will quickly ger-
minate if a dead insect or similar object be
thrown in.

The resting spores are from 1 to 20, while
the active gonidia are from 5 to 150, the
number depending in each case on the size
of the sporange, not upon the size of the
spores or gonidia, which is tolerably regular.
Pringsheim states that starch occurs in
the contents of the resting spores of S.
ferax.

A third form of reproductive organ is
described by Cienkowski, which in the
earlier stages resembles a sporange of rest-
ing spores j but the spores produce each a
long tubular neck, which bores through the
wall of the sporange and discharges its con-
tents as minute swarming bodies into the

water ; these have not been seen to germi-
nate. These flask-shaped bodies resemble
the formations seen by Carter in SPIRO-
GYBA; and we have seen them in other
Algae. Al. Braun at first described them
as a species of CHYTRIDIUM, but subse-
quently has expressed an inclination to
regard them as antheridial spores of
Aclilya.

In addition to the above, Al. Braun has
described curled tubular processes, resem-
bling the horns of Vaucheria, associated with
the sporanges in which resting spores are
formed; and he is inclined to regard them
as anthet'idia exercising a fecundating office,
like the horns of Vauclieria. Similar bodies
have been recorded in other Saprolegnice,
especially in Aclilya cornuta. (See PI. 27.
figs. 22-27).

A. lignicola is found upon wood in water.

BIBL. A description of the supposed species
will be found in Kiitzing's Sp. Algarum,
p. 159. For further information on the de-
velopment, see Al. Braun's Rejuven. (Ray
Society, 1853, pp. 188, 268) ; Pringsheim,
Nova Acta, xxiii. pt. 1. p. 397-460, 1852 ;
Anton de Bary, Sot. Zeit. x. p. 473, 1852 ;
linger, Linncea, 1843, p. 129 (Ann. d. Sc.
Nat. 3me ser. ii. p. 5. pi. 1, 1844) ; Meyen,
Pflanzenpliys. iii. 457 ; Nageli. Zeitschr.filr
Wis. Bot. heft 1, p. 102, heft 3, 4, p. 28
(Ray Soc. 1845, p. 278, 1849, p. 101) ; Thu-
ret, Ann. d. Sc. Nat. 3me ser. t. xiv. p. 20,
p. xxii, 1851 j Ch. Robin, Veget. Paras. 2nd
edit. 1853, p. 372 ; Varley, Tr. Mic. Soc.
iii. ; Cienkowski, Bot. Zeit. xiii. p. 801 ; Al.
Braun, Chytridium, Abh. Berlin. Ak. 1855 ;
Verjung. in d. Natur, p. 318 (Ray Society,
1853, p. 298). A list of all the writers who
had treated of Aclilya before 1843 is sub-
joined to Unger's Essay in the Linncca ;
Pringsheim, Jahrb. Bd. 1. heft 2, bd. 2. heft
2; Archer, Qu. Mic. Jn. 1867, p. 126 ;
Sachs,j5o£. 1874, p. 276 ; Pfitzer, Monatsber.
d. Berl Akad. Mai 1872 ; Grevillea, March
1878 (woodcuts).

ACHNAN'THES, Bory.— A genus of
Diatomacege (Cohort Achnanthese).

Char. Frustules compressed ; either sin-
gle, in pairs, or united into a straight fila-
ment ; geniculate in front view, without
septa j attached by a stipes fixed to one an-
gle ; uppermost valve with a longitudinal
median line, lowermost with a longitudinal
line, and a median nodule or stauros.

The individual frustule, when single, or
the lowermost when they are united, is
furnished with a stipes or stalk, arising

ACHNANTHIDIfJM.

ACHORION.

from one end of the lower margin. Side
view of frustules elliptical, oblong or linear,
sometimes slightly constricted in the mid-
dle ; markings of upper and lower valves
different, the upper (PL 16. fig. 2) exhibit-
ing transverse rows of dots (appearing like
striae under a low power) interrupted by a
longitudinal line, the lower (PI. 16. fig. 3)
being also furnished with transverse rows
of dots, interrupted by a stauros, as also by „
a longitudinal line which in some has a no-
dule at each end. The valves being much
compressed, the transverse rows of dots ap-
pear also in the front view. The hoops
exhibit faint longitudinal and sometimes
transverse striae.

Aclmantlies resembles Striatella in its
stalked flag-like filaments, but may be known
from it by the absence of internal siliceous
plates or vittae.

Species : —

Freshwater; markings faint (minntc) A.exilis*.
Marine or brackish water; markings
distinct.

Stipes longer than frustules A. longipes\ .

Stipes shorter than frustules.

Ends of valves acute A. brevipes.

Ends of valves obtuse A. subsessilis.

* PL 16. fig. 4. t PI. 16. fig. 1.

Kiitzing enumerates 15 species of Ach-
nanthes.

BIBL. Ralfs, Ann. N. Hist. xiii. 489;
Kiitzing, Bacill. p. 75, & Sp. Aty. p. 54 ;
Smith, Brit. Diat. ii. 25 j Rabenhorst, Fl.
Ala. 109.

ACHNANTHIDTUM, Kiitz.— A genus
of Diatomacese (Cohort Achnanthea?).

Char. Those of Achnanthes, mostly sin-
gle, and without the stipes.

Five British species ; freshwater : —

Filament of numerous frustules ... A. lanceolatum.
Frustules few, valves constricted

in middle. A. coarctatum.

Frustules few, often straight; valves

constricted near the end A. mieroccphalum* .

Frustules few; valves obtuse, un-

constricted A. lineare.

Frustules few, median line sigmoid A.jlexellum].

* PL 16. fig. 5. f PL 16. fig. 6.

Frustules very small, and markings very
faint.

BIBL. Smith, Brit. Diat. ii. 30 j Kiitzing,
Bacill. 75, & Sp. Alg. 53.

ACHO'RION, Link and Remak.— The
generic name applied to one of the vegeta-
bles occurring in Favus, and characteristic
of that disease of the skin (also called
Porriyo or J'inea favosd) . The structure of
the plant, Achorion Schcerileimi, bears
much resemblance to that of the genus

Torula ; but it occurs in definitely bounded
patches having a special arrangement of
the microscopic elements of which it is
constituted.

Much has been written by medical authors
regarding these bodies ; but we shall not
enter into this part of the subject here, fur-
ther than to state that the presence of this
vegetable structure seems to be essential
and causative in the disease of the skin to
which we have alluded. Remak was unable
to make any of the spores germinate in or
on animal substances ; some however emit-
ted prolongations when placed upon an
apple; but the surface then decayed and
turned brown within the week, and became
covered with mildew (Penicilliumyhmcum).
One of the entire corpuscles kept upon the
arm for several days, fell off without leaving
any mark; but a fortnight after a/a WM began
to be developed. Gruby states that he inocu-
lated various parts of the body with it, and
even caused it to grow upon wood(?). Ben-
nett ultimately confirmed the statements of
Gruby as to the inoculation.

Unfortunately, most authors who have
written on the parasitic fungi which occur
in morbid conditions of the human frame,
or are productive of disease, have not been
well acquainted with either Fungi or Algae.
Numberless names have been assigned to
them j and in consequence, while many of
these organisms have been considered Al-
gae, they have been regarded by others as
Fungi. It is, however, probable that all of
them are mere conditions of the most uni-
versally diffused species of Pcnicillium, As-
pergillus, Mucor, or Cladosporium — genera
which are capable of propagation by cells
thrown off from the threads, other than the
normal fruit. It is quite impossible that,
as supposed by Ardsten, such a genus as
Puccinia could be produced on animal
tissues.

BIBL. Ch. Robin, Veg. parasites, 1853,
(plates, 2nd edit.) j Bennett, Month. Jn.
Med. Sc. 1850 (figs.), and Tr. Roy. Soc.
Edinb. 1842, xv. pp. 227-294; Gruby,
Compt. Rend. 1841, xiii. p. 72 ; Mycodermes
fyc., ibid., 309; Tinea favosa, Midler's Ar-
chiv, 1842, p. 22 ; Hannover, Midler's Arch.
1842, p. 281-295, pi. 15. figs. 7-9 ; Miiller
and Retzius, Mull. Archiv, 1842, p. 192, pi.
8 and 9 ; Lebert, Phy. Path. ii. p. 477, Paris,
1845 ; Remak, Diagn. u. pathogen. Unte.rs.
Berlin, 1846, p. 198-215 ; Bazin,Ze* Teignes,
Paris, 1853, 8vo (plates) j Robin, Micr.
1877, p. 860.

ACHROMATISM.

ACINETINA.

ACHRO'MATISM. — A term properly
signifying freedom from chromatic aber-
ration, but commonly used to denote free-
dom from both spherical and chromatic
aberration.

A GIG UL A'RIA, D' Archiac.— One of the
Foraminifera imperforata, related to Dac-
tylopora, and consisting of numerous cham-
bers arranged in close order side by side
without intercommunication, and forming
minute aciculate cylinders, or narrow ta-
pering plates. Known fossil only in some
Tertiary beds of France.

BIBL. Carpenter, Introd. Foram. 137.
ACINE'RIA, Duj —A genus of Infusoria,
of the family Trichodinia.

Char. Body oblong or lanceolate, de-
pressed, the fore part somewhat obliquely
recurved like the blade of a sabre ; a row of
cilia,directed forwards, arising from one side.
Differs from Trachelius, Duj., in the ar-
rangement of the cilia and in the anterior
curvature ; devoid of a mouth, like Trache-
lius, which especially distinguishes the pre-
sent genus from Pelecida. 2 species :

A. incur vata (PL 30. fig. 1) ; marine,
colourless; length 1-590 inch.

A. acuta (PI. 30. fig. 2), found in fresh
water ; length 1-580 inch.

Dujardin figures in the latter species cilia
upon both margins, those on one side being
directed forwards, and those on the other
backwards.

Claparede and Lachmann refer these to
AmpMleptus.

BIBL. Dujardin, In/us, p. 402 ; Clap, and
Lachm. Inf. p. 356.

ACINETA, Ehr.— A genus of Rhizo-
poda, belonging to the family Acinetina.

Claparede and Lachmann enumerate 8
species.

A. mystacina (PL 51. fig. 11). Yellowish
brown, rounded, tentacles in two bundles j
1-120 to 1-800. On Lemna minor.

A. patula (PL 51. fig. 12). Body as if
resting on a cup-shaped carapace, variable
in form; contains brown granules. On
marine Algse. Norway. Length 1-100".

A. tuberosa (PL 30. fig. 4). Colourless
or yellowish brown, triangular when ex-
panded; tentacles arising from the distal
angles only. Salt or brackish waters; 1-1CO"
to 1-410".

A. Lynybyi, ferrum-equinum, and cylin-
drica are "referred by Ci. and Lachm. to
Podophrya.

A. Notonectce. On the hairs of the legs of
N. f/lauca.

BIBL. Pineau, Ann. d. So. Nat. 3 s6r. Zool.
iii. & ix.; Ehr. Inf.; Duj. Inf.; Claparede
and Lachmann, Etudes, '$c. ;' Ann. N. H.
1857, xix. ; Stein, Infus.; Gegenbaur,
MorpJi. Jahrb. 1875.

ACINETI'NA,Ehr.— A family of Radio-
larian Rhizopoda.

Char. Those of the Actinophryina, but
with usually capitate and suctorial tubular
tentacles, the body being more or less en-
closed in a carapace, which is generally
prolonged to form a stalk.

The structure and relations of these ani-
mals are still very unsettled. The re-
searches of Pineau and Stein tended to
render the existence of the species doubtful,
by showing that they were stages of deve-
lopment of Epistylis, Vaginicola, Vorticetta,
&c. ; but this has since been found to be in-
correct. They exhibit a nucleus, and one
or more contractile vesicles. The remark-
able suctorial character of the tentacles has
not been proved to occur in all the genera
and species. Many, however, have been
seen to take food voraciously, which is thus
effected : when an Infusorium touches the
button-like end of the tentacle, it usually
remains adherent to it ; the end becomes still
more dilated so as to constitute a sucking
disk, and the ray becomes thicker and
shorter, the other rays at the same time
making grasping moVements and endea-
vouring to attach their extremities to the
captured prey. A current of chyme-par-
ticles is then soon seen running 'from the
captured infusorium into the body of the
Acineta. The chyme-particles form at first
a slender row,but afterwards collect in a drop.
The body of the Acineta then becomes
opaque, from the collection of the drops.

The colourless or coloured ova described
by Ehrenberg are partly chyme-particles,
partly oil drop-like globules which make
their appearance in the AcinetcB after ani-
mal food. The ciliated swarm-germs to
which they give origin have been traced
directly into Acinetce. Fission has been
observed in Acineta mystacina, not in the
others. The genera may be thus divided :

^Tentacles not borne upon a proboscis.
Tentacles unbranched.
. Stalks simple.

(A peduncle 1. Podophrt/a.

No shelH No pedun- (free .. 2. Spkarophrya.
I cle } fixed. 3. Trichophrya.]

A a\,^-i j Peduncle present . 4. Acineta.

1 1 Peduncle absent... 5. SolenopJirya.

Ftalks branched 6. Dendrosoma.

Tentacles branched 1. Dendromycetes.

**Tentaoles borne on a long pro-
boscis 8. Ophryodetidrion.

ACOMIA.

ACROSTALAGMUS.

Here belong, perhaps, the genera Core-
thria, Ephelota, and Zuoteira (Wright) j and
Alder's animalcules.

ACO'MIA, Duj. — A genus of Infusoria,
of the family Enchelia.

Char. Body oblong-ovate or irregular,
colourless or granular, turbid, composed of
a glutinous homogeneous substance con-
taining irregular granules, and ciliated only
or principally at one end. Dujardin de-
scribes eight species, to which Perty adds
one.

Marine, or inhabiting decomposing in-
fusions. Minute and colourless.

A. vitrea (PL 30. tig. 3) ; freshwater :
length 1-868.

BIBL. Duj. Infus. p. 382 j Perty, Zur
Kenntniss, fyc. p. 149.

- ACONTIOPH'ORUS, Brady. A genus
of Entornostraca, Ord. Copepoda.

A., scutatus and A. armatus] marine;
around the British coasts.

BIBL. Brady, Copepoda (Ray Soc.}, 3. p. 69.

ACREMO'NIUM, Link— A genus of
Hyphomycetous Fungi, belonging to the
division Mucedines; distinguished by its

C:ed threads bearing numerous patent
chlets, each of which is terminated by

Fig. 2.

Acremonium fuscum (magnified).

a single globose spore. Perhaps only states
of some other genus. British species :

A. verticillatum, Link. On dead wood,
trunks of trees.

A. alternatum, Link. On decaying
leaves.

A. fuscum, Schmidt (fig. 2). On dead
wood and sticks.

A. ranigenum, B. and Br. On dead frogs.
Distinguished by the threads being matted
together below into a distinct stem.

BIBL. Engl. Flora, v. pt. 2. p. 347;
Greville,#cott. Cryp. Fl. 1. 124. figs, land 2;
Berk, and Br. Ann. N. Hist. 1871, June.

AC ROC AR'PL— An artificial division of
Mosses (see MOSSES).

ACRO'PERUS.— A genus of Entomos-
traca, of the family Lynceidse (Baird).

Char. Shell somewhat harp-shaped, the
anterior inferior margin projecting and ob-
tusely angular, inferior antennae long ; beak
blunt, very slightly curved downwards;
shell striated with longitudinal ribs directed
obliquely down wards and forwards; colour-
less. 2 species : —

A. harpce (PI. 19. fig. 1) ; each branch
of inferior antennae with 3 long setae from
the extremity of the last joint only.

A. nanus (PI. 19. fig. 2), much smaller
than the last ; anterior branch of inferior
antennae with 4 setae, one arising from the
second, and three from the end of the last
joint.

This genus is scarcely distinct from Camp-
tocercus.

BLBL. Baird, Ann. N. Hist. xi. 91 ; and
Brit. Entomos. 129.

ACROSPER'MUM, Tode.— A genus of
Sphaeronemei (Stylosporous Fungi), con-
sisting of minute, somewhat cartilaginous
perithecia, a few lines high, discharging
long, wavy, erect, simple, microscopic spores
from a terminal pore or ostiole. British
species : —

A. compressum, Tode. On dry stalks of
herbaceous plants.

A. graminum, Libert. On dead grasses.

A. cornutum, which is not uncommon
on the gills of blackened Agarics, is merely
the winter resting-state of Agaricus tube-
rosus.

BIBL. Engl. Flora, v. pt. 2. p. 221 ;
Grev., Sc. Crypt. Flora, t. 182.

ACROSPO'RIUM, Nees.— A generic
name formerly applied to certain species of
Oidium (see OIDIUM).

ACROSTALAG'-
MUS, Corda. — A genus
of Mucorini (Phycomy-
cetous Fungi), distin-
guished by its whorled
branched septate
threads, each branch
terminated by a globose
vesicle, which is pierced
by the tip of the branch-
let, from which nume-
rous spores are given off
within the vesicle.

VerticiUiumlateritium
is a form of this beauti-
ful mould, with minute
naked spores.

The accompanying

figure represents Aero- Acrostalaemns cinnaba-
7 . rinua (highly niagm-

stalagmus cinnabar mm, fied).

Fig. 3.

ACROSTICHE^E. [ 1)

Corda. It grows in large patches on rotten
potatoes. Hoffmann regards it as a mere
form of Trichothecium roseum, which is
rather a Dactylium.

BIBL. Berkeley, Cryptog. Bot. p. 294;
see also TRICHOTHECIUM and VERTICIL-
LIUM.

ACROSTICH'E^E.— A family of Poly-
podiaceous Ferns, with naked sori.

Illustrative Genera.

Acrostichum. Sori seated on all the veins,
venules, and parenchyma, sometimes on
both surfaces; veins very much branched,
and anastomosing in more or less regular
meshes.

Platycerium. Sori forming large patches
on the lower surface of the fertile fronds,
which are dichotomously forked with stag's-
horn-like divisions.

ACROS'TICHUM, L.— A genus of Acro-
sticheee(Polypodiaceous Ferns), with naked
sori seated on all parts of the leaf. Species
very numerous, mostly tropical. See
HAIRS.

ACTIN'IA.— A genus of Ccelenterata
(Zoophytes) ; class Actinozoa.

Char. Body conical or cylindrical, ad-
hering by a broad discoidal base ; mouth
simple, superior, surrounded by one or more
uninterrupted series of conical, undivided,
tubular retractile tentacula ; marine.

The species are commonly known as sea-
anemones, and are found on the sea-coast
adhering to rocks and stones. A. mesem-
bn/anthemum (1-1£" diam.), with numerous
azure-blue tubercles surrounding the mar-
gin of its oral disk, is very common on the
British coast.

The body is formed of a thick coat, the
inner layer of which consists of longitudinal
and transverse unstriated muscular fibres.
The tentacles are covered with stinging
threads and capsules, as in the Acalephae,
often forming beautiful objects ; and at
their bases are often found chromato-
phores. The space between the stomach
and the skin is divided into cellular
spaces by radiate partitions or mesen-
teries, the ovaries and the spermatic convo-
luted tubes being attached to these parti-
tions.

The connective tissue of the body is com-
posed of numerous fibres, cells, and inter-
mediate stages, of extreme delicacy (PL 41.
fig. 1). Dispersed throughout it are nume-
rous spindle-shaped, flexible, organic spi-
cula (PI. 41. figs. 1 a and 2), many of them

ACTINOCOCCUS.

curiously marked by interrupted transverse
markings (fig. 2).

In reproductive power they almost equal
;he Hydrae ; when cut across, new tentacles
?orm in a few weeks on the lower half, and
each piece becomes a new animal. They are
usually propagated by ova ; the embryos
being ciliated. Many of the species exhibit
he most splendid iridescent colours.

BIBL. Johnston, Brit. Zooph. ; Tugwell,
Common English Sea-Anem. ; Gosse, Acti-
nol Britann. 1860, Mar. Zool. 1, and " De-
vonshire Coast'" Bronn, Die Klass. fyc. d.
Thierreichs ; Gegenbaur, Vergl. Anat. 1878 ;
Nicholson, Zool. p. 178 ; Strieker, Human
Sf Comp. Histol.

ACTINIS'CUS, Ehrenberg.— A doubtful
genus of Diatomaceae,provided with siliceous
shells bearing radiating spines. (Cohort
Actiniscese.)

Char. Individuals microscopic, solid, ra-
diate, resembling a star ; marine.

These organisms, which are found both
recent and fossil, are especially remarkable
for their valves being frequently found per-
forated. Species : —

A. Tetrasterias, Ehr. (PI. 18. fig. 1).
Stellate, with 4 free ray_s; diam. 1-1000".
Virginia. — A. Pentasterias, Ehr. (PI. 18.
fig. 2). Rays 5 ; diam. 1-1200". Recent on
the shores of Norway ; fossil in the chalk-
marl of Greece. — A. quinarius, Ehr. (PI.
18. fig. 3). Stellate, rays 5, free; diam.
1-3000". ^Egina.— A. Sirius, Ehr. (PI. 50.
fig. 45). Rays 6, acute, winged at the
base; diam. 1-1200". Shore of Norway,
recent.— A. Discus, Ehr. (PI. 18. fig. 4).
Disk-shaped, centre smooth, 8 marginal
rays not exserted; diam. 1-1200". Oran.
— A. Rota, Ehr. (PI. 18. fig. 5). Disk-
shaped, centre smooth, 10 marginal rays
exserted; diam. 1-1900". Oran. — A.Lan-
cearius, Ehr. Stellate, with 8 marginal lan-
ceolate rays, and some central rays which are
shorter on one side; diam. 1-240". Ant-
arctic Ocean.

BIBL. Ehrenberg, Leb. Kreidethierchen,
1840, p. 69; Monatsber. 1844, p. 76, &c. ;
Kiitzing, Bacillarien, 1844, p. 139; Spec.
Algai-urn, 1848, p. 141.

ACTINOB'OLUS, Stein.— A genus of
Infusoria.

BIBL. Kent, Infus. 1880, p. 214.
ACTINOCLA'blUM, Ehr.— A genus of
Mucedines (Hyphomycetous Fungi). No
British species vet recorded.

ACTINOCOC'CUS, Kiitzing.— A genus
of exotic Algae (marine), referred to Ri-

ACTINOCYATHUS.

[ 14 ]

ACTINOPHRYS.

vularia by Suhr (Kiitz. Tab. Phyc. 31,
fig. 2).

ACTINOCY'ATHUS, Kent.— A genus
of Infusoria.

BIBL. Kent, Man. Inf.

ACTINOCYC'LUS.— A genus of Dia-
tomacese (Cohort Coscinodiscese).

Char. Frustules solitary, free or adherent
to other bodies ; disk-shaped ; valves circu-
lar, exhibiting cellular markings, with rays
or bands radiating from the centre, which
is free from the cellular appearance; no
internal septa ; marine.

The cellular appearance arises from the
existence of depressions upon the surface.
The radiant bauds arise from undulations
of the surface, which are best seen in the
front view (PI. 25. fig. 17 b).

A. undulatus (PI. 25. fig. 17 a) ; rays 6,
diarn. 1-250 to 1-1100".

Kiitzing enumerates 34 species; some are
found fossil.

Smith admits A. duodenarim (rays 12),
A. sedenarius (rays 16), and A. octodenarim
(rays 18) as British — species referred by
Ehrenberg and Kiitzing to the genus Acti-
noptychus. These are found in the Medway.

BIBL. Ehrenberg, Leb. KriedethiercJie-n,
1840, p. 57 ; Monatsber. 1844, and Mikrog. ;
Kiitzing, Bacillar. 1844 ; Sp. Alyarum,
1849; Roper, Mic. Jn. ii.; Smith, Brit.
Diat. i. 25, and ii. 86; Rabenhorst, Fl. Alg.
35.

ACTINODIS'CUS, Grev.— A genus of
Diatom acese.

Char. Frustules free, disk-shaped ; valves
granular, with a central nucleus, and nu-
merous (15) linear smooth rays extending
from it to the margin.

A. Barbadensis (PI. 36. fig. 22). Diam.
1-250". In the Barbadoes deposit.

BIBL. Greville, Micr. Trans. 1863, 69.

ACTINOGO'NIUM, Ehr.— A genus of
Diatonaacese.

Char. Prismatic, frustules not forming
a filament, subspherical, with 7 or more
angles.

A. septenarium (PI. 18. fig. 8). With 7
angles. Found fossil in Barbadoes earth,
with Polycystina.

BIBL. Ehr. Monatsber. d. Berl. Ak. 1847 ;
Ann. N. Hist. vol. xx. p. 127.

ACTINOM'ONAS, Kent— A genus of
Infusoria, Ord. Flagellata (Radio-flagellata,
Kt.).

Char. Resembles a stalked Actinophrys
with a long anterior flagellum ; neither test
nor central capsule.

2 species:— A. mirabilis (PI. 53. fig. 1);
diam. 1-2000". A. pusilla; diam. 1-3250".

BIBL. Kent, Infus. p. 227.

ACTINOPHRYl'NA, Duj.— A family
of Radiolarian Rhizopoda.

Char. Body usually rounded, contained
in a shell or shell-less, giving off radiate
non-agglutinating pseudopodia, either from
the entire surface, or from parts only ; ,spi-
cules and spines absent.

The genera may be divided thus : —

Shell absent.
Pseudopodia arising from all parts of

the surface Actinophrys.

(Acanthocystis.)
Pseudopodia arising from a zone near

the circumference Trichodiscus.

Pseudopodia arising from one side I'luyiophrys.

Shell present.
Free.

Incrusted with foreign matter Pleurophrys.

Not incrusted, oblong.

Orifice lateral Trinema.

Orifice terminal Euytypha.

Attached to foreign bodies Urnula.

BIBL. That of the genera.

ACTI'NOPHRYS, Ehr.— A genus of
Actinophryiua.

The species of Actinophrys are found in
both fresh and salt water. The body ex-
hibits contractile vesicles, mostly near the
margin, but sometimes more diffused and
giving it a cellular appearance. Conjugation
has been repeatedly observed ; but authors
are not agreed upon its import. The move-
ment of the pseudopodia is very slow ; gra-
nules may be seen continually moving in
them, as in the Gromida and Foraminifera ;
but the circulation is much slower, and
requires great attention and a high power
to render it visible.

A. sol, E. (PI. 30. fig. 7 b). Spherical,
colourless, whitish tentacles radiating from
all parts of the body; 1 or 2 contractile
vesicles strongly projecting on the surface ;
parenchyma not reticular; diam. 1-430 to
1-1200"; fresh water.

A. Eichornii, E. (PI. 30. fig. 7«). As
A. sol, but parenchyma presenting a more
or less regular cellular appearance; diam.
1-100".

A. marina, D. As A. sol, but marine,
rather smaller, and movements of tentacles
more rapid.

A. brevicirrhis, P. Greenish, not reti-
cular ; pseudopodia very short and very
numerous.

A. pennipes, Cl. & L. Not reticular;
pseudopodia few, slender, and very long;
no projecting vesicle.

A. viridis, E. (PI. 30. fig. 6). Spherical ;

ACTINOPTYCHUS.

ACTINURU&

greenish ; rays shorter than the body ;
diam. 1-280" to 1-620"; fr. water. Per-
haps A. sol coloured by chlorophyll.

A. diyitata, D. Colourless, depressed,
tentacles flexible, thickened at base, and
when contracted forming finger-like pro-
longations ; diam. 1-770"; fr. water.

A. (jranata, D. Spherical; opaque in
centre; rays taper, shorter than body;
fr. water.

A. paradoxa, Carter (PL 61. fig. 13).
With numerous capitate and longer simple
tentacles; fr. water. Bombay.

A. oculata, St. = A. sol? A. discus, D. —
Trichodiscus sol, E. (PI. 32. fig. 8). A. pe-
dicellata, D — Podophrya fixa, E. A. stella,
Perty = the eggs of one of the Rotatoria.

The manner in which these animals feed
is curious. Any part of the surface of the
body may be converted into a temporary
stomach. When an infusorium or a minute
alga comes into contact with one of the
tentacles, it generally becomes adherent.
The tentacle with the prey then slowly
shortens, and the surrounding tentacles ap-
ply themselves upon it, bending their points
around the captive, so that it gradually be-
comes enclosed on all sides. In this way
the prey is gradually brought to the surface
of the body, The spot at the surface of the
bodv upon which the captured organism is
lying slowly retracts, and forms at tirst a
shallow depression, which gradually becomes
deeper and deeper, in which the organism is
finally lodged. As the depression becomes
still deeper, its edges coalesce, and thus a
cavity closed on all sides is formed, in which
it remains for a certain time and becomes
digested. If there be any indigestible resi-
due, a passage for its exit is formed, and it
is expelled by further contractions of the
substance of the body, and in the same or a
different direction from that at which it
entered, the canal and the aperture entirely
disappearing.

BIBL. Kolliker, Zeifschr. f. ivissens. Zool.
Bd. i. (Qt. Micr. Jn. i.) ; Stein, Archiv f.
Naturyesch. 1849 ; Brightwell, In/us, of
Norfolk ; Pritchard, Infus. ; Carter, Ann.
N. Hist. 1864 ; Claparede and Lachmann,
Etudes ; Pertv. Z. Kenntniss fyc. p. 159.

ACTINOPTYCHUS, Ehr.— A genus of
Diatomacese. (Cohort Coscinodisceae.)

Char. Frustules solitary, free, disk-shaped,
with rays and internal radiating septa;
valves apparently cellular (areolar), except
opposite the rays.

The presence of true internal septa is

doubtful; hence it becomes a question
whether this genus should not be consoli-
dated with Actinocyclus.

Kiitzing enumerates 16 species, distin-
guished principally by the number of septa
and rays ; A. temarius, septa 3 ; A. quater-
narius, septa 4 ; A. senarius, rays 6 (PL 25.
fig'. 16), &c. A. hexapterus, with 6 thick,
solid conical rays, is one of the calcareous
corpuscles of an echinoderni ; the margin of
the disk thick, undulate, and toothed within.
Many of the species are fossil.

BIBL. Ehrenberg, Infus. Abh. d. Berl.
Akad. 1838, and Berl. Bericht. 1844 ; Kiitz-
ing, Bacill. 134; Sp. Alg. 130; Greville,
Micr. Trans. 1866, p. 5 ; Rabenhorst, Alg.
p. 35.

ACTINOSPH^'RA, Perty.-A doubt-
ful genus of Rhizopoda.

Char. Body minute, spherical, surrounded
with irregular, rather rigid processes. Move-
ment that of swimming on various axes.

Processes stout and taper. Body colour-
less, containing greyish-green (food-) spots.

BIBL. Perty, Zur Kenntniss fyc. p.189.

ACTINOSPH^E'RIUM = Actinophnjs,
in part.

ACTINOTHYR'IUM,Kunze.— A genus
of Sphseronemei (Stylosporous Fungi),
forming minute round, Fig. 4.

flat, black spots, with a
central boss of close,
radiatingjfibrous struc-
ture. British species: —

A. yraminis, Kunze.
On leaves and stalks of

Grasses in spring (fig. Actinothyriumgraminis

4). The innate, radi- 0"ghly magnified),
ately fibrous, shield-like perithecium finally
dissolves at the apex. The stylospores,
which are spindle-shaped, are formed be-
neath the disk, attached by their bases;
Fries conjectures that they are transformed
asci.

It is probably a state of some Sphceria or
allied genus.

BIBL. Greville, Crypt. Flora, t. 218.

ACTINOT'RICHA, Kent.— A genus of
Infusoria, fam. Oxy trichina.

ACTINU'RUS.— A genus of Kotatoria,
of the family Philodinaea, Ehr.

Char. Eye-spots two, frontal (red) ; tail-
like foot with 2 lateral horny processes and
3 terminal toes. (Rotifer with 5 points to
the foot.)

Agrees with Rotifer in general structure ;
teeth 2 in each jaw (PL 43. fig. 2).

1 species, A. Neptunius (PL 43. fig. 1).

ADELOSINA.

C 16 ]

ADULTERATIONS.

Colourless, body attenuated ; length 1-18"
to 1-36". Very common, aquatic.

ADELOSI'N A, D'Orb.— A t first regarded
as a generic form, but now recognized as
only the young condition of some of the
Milioline Irnperforate Foraminifera. Spi-
roloculina, Quinqueloculina, and Triloculina,
subgenera of Miliola^ commence their
growth, after the fashion of their conge-
ners also, with a relatively large, subglo-
bose " primordial chamber ;" and the suc-
ceeding growth produces a curved flask-
like chamber, closely enwrapping one side
of the former. Until the successive lateral
overlappings by new chambers build up the
nearly oval outline of the adult Miliola, the
young shell is one-sided, and may be termed
u Adelosina." Found in all seas, and com-
mon among Tertiary and Cretaceous fossils
at many places.

BIBL. Carpenter, Jntrod. Foram. 75 ;
D'Obigny, For. foss. Vienne, 301.

ADE'NOID or Retiforin Tissue.— A va-
riety of connective tissue, consisting of very
fine fibres, forming a network, in the meshes
of which are found numerous lymph-cor-
puscles. It forms the stroma of the spleen,
the lymphatic glands, &c. The fibres are
formed by the union of the processes of the
original connective-tissue cells. See GLANDS
of Animals, and LYMPHATICS.

ADENO'MATA. These are tumours com-
posed of new formations of glandular tissue.
They occur in the mamma, mucous mem-
branes, the sebaceous and pineal glands, the
ovaria, and the liver.

BIBL. Green, Pathol ; Rindfleisch, Path.
1878.

ADENOPLEU'RA,Macalister. — A genus
of Acarina, fam. Ixodidse.

A. compressum. Found between the
scales of the West- African Pangolin (Mania
multiscutatd). L. 1-16".

BIBL. Macalister, Qu. Mic. Jn. 1872, xii.
p. 287 (figs.) ; Murray, JEcon. Entom. p. 200

(fig-)-

ADIANTUM,Linn.— A genus of Pteridese
(Polypodiaceous Ferns), with one elegant
indigenous (fig. 5), and many exotic species.

ADULTERATIONS (PI. 2).— A very
important use to which the microscope is
applicable, consists in the detection of vari-
ous adulterations of articles of food, drugs,
and products of the arts and manufactures.

The first point in a question of adultera-
tion is, to determine, by microscopic and
micro-chemical analysis, the structure and
composition of the pure substance ; and if

the Table given at the end of the Introduc-
tion be kept in view in this proceeding, but
few points will probably be overlooked. On
then comparing these results with those
obtained by a similar mode of proceeding- in
regard to a suspected substance, there will
in general be found little difficulty in deter-
mining whether it is pure or not. If im-

Fig.5.

Adiantum Capillus Veneris (pinnule with
sori covered by indusia) ; 5 diam.

purities or adulterating ingredients are pre-
sent, the next point will be to determine
their nature. To do this with certainty,
would require that the structure and com-
position of every kind of substance, either
natural or artificial, should be known, which
would imply an amount of knowledge pos-
sessed by no one. But the question is sim-
plified in practice, because substances used
in adulteration must be cheap, and either
grown or manufactured in quantities at
home, or imported from abroad. Hence
they are generally common, and it is pretty
well known of what they will probably con-
sist. In Plate 2 will be found the true
structure of the adulterated articles and
that of the adulterants. When the adul-
teration consists of a chemical substance as
it might be called, i. e. a salt, metallic oxide,
proximate principal, &c., its nature is readily
determined by chemical analysis ; but when
it consists of a vegetable tissue, which has
been perhaps subject to a partly chemical
process of manufacture, the judgment must
be based upon the form of the various parts,
their size, relative position, and other par-
ticulars holding a place in the Table already
alluded to.

ADULTERATIONS.

The following list of adulterations of
articles of general consumption will serve as
a guide to the inquirer, and as an index to
the special articles in this work in which
further details will be found.

ARROW-ROOT (PI. 46. fig. 26).— Cheaper

kinds of starch.
BREAD. — Mashed potatoes, bean-flour,

rice, alum.

CAYENNE PEPPER. — Ground rice, mus-
tard-husks, deal sawdust, formerly
mineral colouring-matter of lead, &c.
CHICORY. — Roasted flours of corn and
beans, acorns, mangold- wurzel, parsnips,
carrots, mahogany-sawdust, burnt
sugar, red ochre, &c.
CINNAMON. — Flour of grain and potato,

cheap starches, &c.

COCOA and CHOCOLATE (fig. 4). — Arrow-
root and other starches, flours, sugar,
chicory, red ochre, &c.
COFFEE (fig. 5). — Chicory and its adul-
terations, as above, locust-beans, date-
stones, and figs.
CURRY POWDER. — Flour, ground rice,

red lead, red ochre.
FLOUR (PL 46). — Meal of other grains,

beans, potato-starch, rice.
GINGER. — Flours of various kinds, mus-
tard-husks, cayenne pepper, turmeric.
ISINGLASS. — Gelatine from bones.
LARD. — Potato-flour.
MUSTARD (fig. 11). — Flour, turmeric.
OAT-MEAL. — Barley-meal.
PEPPER and other spices (fig. 12). —
Flours of grain, peas, potatoes, &c.,
ground mustard, linseed, rice-husks, &c.
PICKLES. — Dilute sulphuric acid (vitriol)

instead of vinegar.
SUGAR.— Potato-flour, starches.
TEA (fig. 1). — Various leaves (sloe, elder),
catechu, mineral colouring-matters,
iron-filings, rice-husks.
TOBACCO (fig. 16). — Various leaves (dock,

rhubarb, coltsfoot), paper, &c.
B i BI>. Ure, Diet, of Arts and Manufactures ;
Mitchell, Adult, of Food; Normandy, Hand-b.
Commercial Analysis; Schacht, Priif. d.
im Handel vork. Geivebe, 1853 ; Wiesner,
Mikroskop, fyc.; Angus Smith, Hep. of Man-
chester Sanit. Assoc. 1863 ; Hassall, Food,
$c. ; Parliam. Rep. on the Adult, of Food,
$c., 1855 ; and Adult, detected, 1857 ; Od-
ling, Journ. Soc. Arts, 1 858, vi. 31 8 ; Gar-
nierand Harell, Falsificat.d. Subst. Aliment.;
Pereira, Mat. Med. ; Sorby on Spectroscope,
in Qu. Mic. Jn. 1809, p. 358 ; Klencke,
Verfalsch. #c. (illustr.), 1879; Soubeiran,

Diet. d. falsif. #c., 1874,- Blyth, Anal, of
Food. Sfc.

^ECID'IUM, Persoon.— A genus of Ure-
dinei (Coniomycetous Fungi), consisting of
parasitic fungi infesting leaves and herba-
ceous stems, appearing in their full-grown
condition as little cups filled with a reddish
or brownish powder (spores), formed by a
raising-up and bursting of the epidermis by
the parasite developed within. Many may
be detected in earlier stages by the deformi-
ties they produce in the growing structure
of the plants infested, or by pale or reddish
spots on the green surface, arising from the
presence of the imperfect fungus under-
neath. These plants are commonly known
under the name of blight, brand, &c. Their
history has recently received much eluci-
dation at the hands of Tulasne, De Bary,
and others ; and they are found to exhibit a
more complicated organization than, was
formerly imagined. The organs of fructi-
fication are produced in two forms, bearing
great resemblance to the conditions lately
ascertained to exist generally in the Li-
chens. A brief account of the natural
history of certain of the species, derived
from De Bary and Tulasne, will give a
general idea of the character of this genus.

The nascent sEcidia are observed as mi-
nute spots upon the herbaceous parts of the
plants which they infest. When sections are
made of these and placed under the micro-
scope, it is found that the parenchyma of
the plant is deformed, irregular, and inter-
rupted by large intercellular passages, among
which ramify the filaments of the mycelium
of the fungus; these are delicate, much-
branched and septate, about 1-3600 of an
inch in diameter. At certain points these
filaments are crowded and interwoven into
hollow globular conceptacles, about 1-180
of an inch in diameter, immediately beneath
the epidermis, the interior of which concep-
tacle is lined with delicate filaments (about
1-12000 of an inch in diameter) arising at
all parts and converging towards the centre,
except at the upper part, (which is open,
and only shut from the external air by the
persistent epidermis of the nurse-plant,)
where they are directed upwards. A gra-
nular mass occupies the centre of the con-
ceptacle, separating the converging fila-
ments from each other. By the growth of
the upper filaments and the increase of the
central granular mass, the whole structure
increases in size, so as to push the epider-
mis up above the surrounding surface, finally

bursting it, when the upper filaments (pa-
raphyses) grow out through the orifice and
form a little funnel-shaped tuft on the sum-
mit of the protuberance, through the middle
of which the granular mass formed below
makes its escape. These bodies may be
found commonly on the spurges (^E". Eu-
phorbice), the barberry (;E. Berberidis), net-
tles (^Z£ Urticce), Compositae (^E. Composi-
taruni), &c., early in the season ; later they
may frequently be recognized in a dried-up
condition, being forerunners of the true spo-
riferous bodies (PL 26. fig. 1). The name
applied to these organs is spermogonia. The
filaments converging into the centre of these,
termed sterigmata (PI. 26. figs. 2, 3, s t), are
the important parts of the structure ; they
terminate in rows of minute bodies of oval
form, about 1-6000 of an inch long and
1-12000 in diameter (ibid, s p}, which be-
come detached and separated, falling loose
into the cavity, where, by a continued
growth and shedding of similar bodies from
the converging filaments, they accumulate to
form the granular mass above spoken of as
existing in that situation. The number
ultimately becomes enormous, and a gela-
tinous substance is secreted, glueing them
into a mass. When placed in water under
the microscope, or when wetted by rain in
its natural position, the ripe mass swells and
is protruded through the orifice of the sper-
mogonium on the surface of the leaf. By a
longer action of moisture the jelly dissolves,
and the minute bodies {spermatia) spread
about in the water, exhibiting "an oscilla-
tory motion, as of a body attached at one
extremity." De Bary states that he found
iodine arrest this motion, while it persisted
for some time in solution of chloride of cal-
cium. No cilia can be detected. Fresh
spermatia were coloured bright purple red
by sugar and sulphuric acid, but at the same
time were so acted on that it could not be
made out whether they possessed a mem-
brane free from nitrogenous matter. Solu-
tion of potash renders invisible the outlines,
not only of the spermatia, but of the sterig-
mata and paraphyses. The resemblance of
these bodies to the spermatia of the Lichens
(see LICHENS), is too evident to be mis-
taken ; hence the same terms are applied to
the corresponding organs.

The spermogonia occur either in regular
groups, or scattered just like the perithecia j
when the latter are on the same surface of
a leaf, they often form a circle round the
former. Frequently they burst through on

i ] ^ECIDIUM.

opposite sides of a leaf j and then the sper-
mogonia are oftenest on the upper, the peri-
thecia on the lower face (PI. 26. fig. 1 sp).

After a number of spermogonia have been
successively developed and discharged their
spermatia, the mycelium, from which they
originated, produces a new globular body
formed of densely interwoven filaments,
usually in the interior of the substance of
the leaf or stem, not immediately beneath
the epidermis, and ordinarily colourless.
Increasing in size in all directions, this glo-
bular body, the perithecium, soon presents
at its base, i. e. the point furthest from the
nearest epidermal surface, another body
composed of very numerous free-ending
filaments enclosed in a cellular membrane,
which body rapidly grows up within the
perithecium, in the direction of the surface
of the leaf or stem. The filaments, at first
very delicate, are crowded very close to-
gether ; and each exhibits in its interior a
row of short, colourless, roundish cellules,
the uppermost of which is always the largest
and the most advanced in development.
These cellules are the spores, and the fila-
ments in which they are found are the spo-
rangia or thecce. The membrane enclosing
the sporangia, the peridium of Persoon,
grows part passu with them, and is com-
posed likewise of rows of cells, which stand
in a circle around the sporanges, but are
firmly connected together side by side by
an intercellular substance ; this membrane
closes in like a bell or vault over the spo-
ranges. By the reciprocal pressure of all
parts, the cells of this membrane, at first
spherical or ovate, become polygonal. At
a certain stage the apex of the perithecium
gives way, so that it forms a kind of cup
around the membrane enclosing the mass
of sporanges arising from the base. The
whole structure has by this time come im-
mediately up to the underside of the epi-
dermis, which is next ruptured, and the pe-
rithecium and the sporanges are protruded,
more or less, according to the habit of the
species (PI. 26. fig. Ip,p). The upper por-
tions of the rows of cells composing the pe-
ridial membrane then separate more or less
from each other, splitting into lobes, so as
to set the sporanges free, and form a kind of
cup with toothed margins seated in the ex-
panded perithecium (figs. 6 and 6 a).

The spores, which are at first delicate
cellules, subsequently acquire a tough mem-
brane, increasing considerably in size, so as
to distend the parent utricle or sporange,

^ECIDIUM.

AERIAL ROOTS.

which is ultimately only recognizable where
it connects the spores together in a monili-
forin series. The spores in most cases now
acquire a deeper colour (except in &. leuco-

jEcidium Compositarum, Mart.
Fig. 6.

Peridia in various stages of growth on the surface of a
leaf: 30 diam.

Fig. 6rt.

Perpendicular section through a burst peridium, show-
ing the sporanges contained in it : 100 diam.

coniwri). owing to contents chiefly accu-
mulated in the centre. Their membrane
is colourless, their form finally irregularly
polygonal ; and the diameter varies much,
even in ripe spores of one and the same
species, from 1-1000 to 1-1800 of an inch.
The upper spores are often ripe at an epoch
when young spores are still in course of pro-
duction at the lower end of the sporanges j
finally, however, the development ceases be-
low, and the tube elongates a little beneath
the lowest spore, forming a kind of pedicle
or basidium to the row. The ripe spores
either soon fall apart and fill the cup as a
loose powder, along with short incomplete
sporanges, or the rows persist even after
they are mature, held together probably by
a firmer peridial membrane.

The British species of dEcidium are nu-
merous; more than thirty are described by
Berkeley in the British Flora, many of
which are common, especially those of the
Mints, the Composites (such as the Colts-
foot, &c.), the Barberry, the Gooseberry,
Buckthorn, Spurge, Nettle, &c. (&. Com-
positarum, Mentlice, Berberidis, Grossularice,
crassum, Euphorbia. Urticcs, ifci).

Oersted and De Bary have made expe-
riments which seem to prove that JEcidium
Berberidis is a development of Puccinia
graminis', a full account of which will
be found in Cooke and Berkeley, Fungi.
p. 180.

BIBL. For Species : — Brit. Flora, ii. pt. 2.
p. 369 j Greville, Sc. Crypt. Flora, pis. 7,
62, 97, 180, 209 ; Reess, Disp. Ured. 1879.

For Anat. and Physiol. : — Unger, Exan-
theme, pp. 297, 300," t. 3. f. 18, 19, t. 4 ;
Meyen, Pftanzenpath. pp. 143, 148-50 ;
Tulasne, Compt. Rendus, March 24 and 31,
1851 j Ann. d. Sc. Nat. ser. 3. t. xv. ; ibid.
ser. 3. t. vii. p. 45 ; ser. 4. t. ii. pp. 12(3, 173 ;
Leveille, Sur le dev. des Uredinees, Ann.
des Sc. Nat. ser. 2. t. xi. ; Corda, Icon. Fung.
iii. t. 3. f. 45 j De Bary, Brandpilze, Berlin,
1853, p. 55 et seq. pis. 5, 6, and 7 ; Sachs,
Botanik, 1874, p. 332 j Henfrey, Bot. (Mas-
ters), 1878, p. 460.

^GERITA, Persoon.— A. genus of Stil-
bacei (Hyphomycetous Fungi) characterized
by short necklace-like threads consisting of
irregular spores produced from flexuous,
branched, radiating sporophores, forming a
subglobose mass. JE. Candida, Persoon,
grows on damp twigs in marshy places,
consisting of scattered white grains about
the size of a poppy-seed. AZ. setosa, Grev.,
belongs to the genus Volutella.

BIBL. Greville, Crypt. Fl. pi. 268. n>. 1 ;
Ann. N. II. 1859, iii. 362, pi. ix. f. 7.

./EGYRIA.— A genus of Infusoria =Zr-
vilia, Duj. A£. legumen=E)-v. legumen, D.
Three other species.

BIBL. Claparede and Lachmann, Infus.
$c. i. p. 288.

ANGSTROE'MIA, Br. and Sch.— A ge-
nus of Leptotrichaceous Mosses, including
many Dicrana, and Ceratodon cylindriciis,
Br. and Sch.

BIBL. Miiller, Synops. Muse. i. p. 426 :
Wilson, Bryolog. Brit. pp. 72, 85.

AERIAL ROOTS.— A very large pro-
portion of the exotic Orchids are epiphytic
plants and produce aerial roots, which "ab-
sorb moisture from the atmosphere; the
same structure occurs in many tropical

c'2

AGATE.

Araceae. The surface of these aerial roots
is clothed by a peculiar tissue, formed of
cells containing a delicate spiral fibre upon
the wall (PL 48. fig. 6)._ The strata of spiral-
fibrous cells are sometimes numerous, and
they cover up the true epidermis of the
root. The growing points of such roots are
green ; but the spiral-fibrous cells soon come
to contain nothing but air, and then assume
a silvery-white colour.

^ETEA, Lamx. See ANGTJINARIA.

^ETHA'LIUM, Link. A genus of Myxo-
mycetes. The common SEthalium, JE. sep-
ticum, L. (flamim, Grev.), occurs frequently
on tan in hot-houses, where it is very inju-
rious, from the rapidity of its growth and the
abundance of its spores. The ordinary form
is yellow ; but violet and reddi.sh-brown
varieties have been met with. It grows
also on mosses in woods. Other species of
AZthalinm have been found growing upon
iron, lead, or other mineral substances,
sometimes a few hours only after they have
been heated, so that the appearance seems
quite marvellous. The cream-like matter,
of which the part answering to the myce-
lium or allied production in other Fungi
consists, exhibits Amceba-like movements.

BIBL. Greville, Crypt. Flora, t. 272;
Sowerby'sJFWftgrs, t. 399. fig. 1 (B&Reticularia
hortensis, Bull.), figs. 3 & 4 (as It. carnosa
and R. cerea) ; Bolton, Brit. Fungi, t. 134
(as Mucor septicus, L.) ; Berkeley, Crypt.
Bot. pp. 236, 339.

AGARICINL— A family of Basidiomy-
cetous Fungi, belonging to the tribe Hyme-
nomycetes, comprising a great portion of
the more important esculent species, cha-
racterized by an inferior hymenium spread
over distinct gill-like processes, which are
often easily divisible into two plates. In a
few species the interstices of the gills are
traversed by veins so as to produce the sem-
blance of pores. Amongst the more obscure
species of the vast genus Agaricus, the hy-
menium is at first superior, but finally be-
comes inferior by the turning over of the
pileus, which is attached at one point only,
or by a very short stem.

The hymenium is composed of vertical
cells, called basidia by Le"veille", sporophores
by Berkeley. These^bodies are elliptical or
elongated cells growing out from the surface
of the lamellae, with four slender stalk-like
processes at the upper end, each bearing a
single spore, which becomes detached when
ripe. These basidiospores are observed by
means of cross sections of the lamellae ; the

sections must be very thin, and require a
high power for satisfactory observation.
The sections keep tolerably well put up in
chloride of calcium or glycerine, and are
most instructive when taken from a series
of specimens of different ages. See AGA-
BICUS, BASHHOSPORES, and HYMENOMY-
CETES. The bodies called cystidia or polli-
naria, are globular or oval cells, found asso-
ciated with the basidia, containing granular
matter exhibiting molecular motion when
discharged. These organs have been sup-
posed to represent antheridia, but are more
probably paraphyses or abortive basidia.

BIBL. Berkeley on the Fructif. of Hyme-
nomyc. Fungi, Ann. N. Hist.i.Sl ; Leveille,
Sur V Hymenium des Champignons, Ann. Sc.
Nat. 2 se"r. viii. 321 ; Hoftman, Bot. Zeit.
xiv. p. 137 ; Cooke, Illustr. Brit. Fungi,
1881.

AGA'RICUS, Linn.— A genus of Agari-
cini (Hymenomycetous Fungi ; one of the
largest genera in the Vegetable Kingdom,
comprising not only a multitude of European
species, but many from tropical climates.
Ag. carnpestris is the common Mushroom.

See HYMENOMYCETES.

AGATE.— The term agate is specially
applied by geologists to the concretions
and geodes of chalcedony, formed in the
steam-holes and the fiss\ires of volcanic
rocks. They consist of crystallized and
crystalline varieties of silica, coloured with
metallic oxides. Successive and concentric
layers of chalcedony, coating the insides of
the cavities, have formed solid or hollow
nodules, the innermost layers being often
colourless or amethystine quartz. In the
chalcedony no definite crystallization can be
seen, only an obscure fibrous structure at
right angles to the planes of deposit, which
latter are usually lumpy or mammillary, and
often render the mass flaky. In some
specimens this fibrous structure becomes
more evident in successive layers — minute,
close-set, crystalline prisms being visible on
fracture ; and these may be succeeded by
regular quartz-crystals. " Those paler vari-
eties of quartz, which consist of concentric
layers of radiately grouped crystalline
needles, frequently polarize light very
beautifully. From the unequal resistance
of some of the layers to hydrochloric acid,
cut agates may be prepared to take printer's
ink and to give impressions on paper. The
relatively open prismatic structure of some
la}7ers allows agates to be partially coloured
by the absorption and carbonization of oil

AGATE.

AGATHISTEGIA.

or honey, or by chemical infiltrations.
Nearly all the agates (onyx, sardonyx, £c.)
of commerce are thus treated. Carnelian
and sard are either burnt or naturally oxi-
dized portions of agate. Sometimes agate
contains crystals of calcite imbedded in its
substance : and whether coated over, or
replaced, these have sometimes given the
outlines in the fortification-agates, which
are common and elegant objects. Small
stalactites, or concentric knobs, of chalce-
dony enclosed and invested in the cavities,
when cut through, give rise to the pretty
eye-agates. Some chalcedonies contain
delicate branching filaments of delessite and
other minerals, and are known as moss-
agates and mocha-stones. Great micro-
scopic interest lies in the so-called moss-
agates of the south coast of England and
the Isle of Wight. These are altered
sponge-masses from the chalk and green-
sand ; and, with the chert and flints, have
been examined by Bowerbank, who sup-
posed them to have originated in the at-
traction and solidification, by sponges, of
silica dissolved in the water of the ancient
ocean. The spicula of sponges are com-
monly found ; also very frequently the
fibres, sometimes in a perfect state of pre-
servation, but usually presenting the ap-
pearance of having suffered to a great extent
from maceration and disruption of their
component parts previous to fossilization.
Generally the fibres adhere together in
confused masses, presenting a moss-like
appearance, with here and there one or two
in a better state of preservation ,• and occa-
sionally, near the outer surface of the mass,
small portions of the tissue are found quite
perfect ; in other parts all the intermediate
states between perfect preservation and
nearly complete decomposition may be ob-
served. The siliceous matter in which these
remains are imbedded, usually presents a
clear and frequently a crystalline aspect,
while the remains of the organized mass
are strongly tinted with colours : bright
red, brown, and ochre-yellow prevail ; but
occasionally the colours are milk-white, or
bright green. Sometimes the interior of
the tubular fibre only is filled with colour-
ing-matter, whilst the sides are semipellucid
or of a milky white ; in others the whole of
the fibres are impregnated with it. PI. 25.
fig. 14 represents sections of a piece of moss-
agate (Indian), showing the silicified fibres
of sponge aa, the gemmules b, a separate
fibre at- c, and spicula at d. Bowerbank

has also described an Alcyonitic structure
in a moss-agate.

The supposed vegetable structures in the
majority of such agates, described by Tur-
mn', Miiller, and others, have been shown
Dy Goppert to be inorganic products,
chiefly dendritic deposits of oxide of iron.
His essay contains an elaborate history of
the strange notions which have at various
times been propounded concerning these
objects. Gergeus has imitated the coloured
confervoid appearances by decomposing
green vitriol with a weak solution of silicate
of soda.

Confervoid bodies, however, have been
recognized in the green moss-agate of In-
dia; and a living Conferva was actually
found in colloid silica by Roberts and
Slack. Schaffner has described green con-
fervoid tissue, referable to Vaucheria, Spiro-
yyra, &c., besides spores, in green Indian
stones ; and he traced the green colour of
the spots in a red opake jasper to Proto-
coccus.

There are two distinct points connected
with the presence of these supposed organic
remains in agate : one is, whether they
really are organic, and the other is whether
they are related to the formation of the
agate, or merely accidentally present. The
first is a very difficult point ; we have only
the microscopic appearance of the bodies
under one set of conditions to judge from :
this is always very unsatisfactory ; many of
the appearances most peculiar to organic
bodies, especially when the latter are not
connected so as to form a tissue, can be
closely imitated by crystallization. Still
the mass of evidence is decidedly in favour
of the appearances really representing por-
tions of sponges and Confervas.

BIBL. Bowerbank, Trans. GeoL Soc. (2)
vi. 181 ; Ann. N. H. x. (1842), 9 and 84 ;
Quart. J. G. S. iv. 319 ; Goeppert, Eatisbon
Flora, 3848, p. 57 ; Brewster, Phil. Mag.
(3) xxii. 213 ; Noggerath, Haidinyer's Nat.
Abhandl iii. 93, 147, and Neues Jahrb. f.
Min. 1847, 473 ; Gergens, N. Jahrb. f. M.
1858, 799; Schaffner, Flora, 1859, no. 36;
Bischof, Lehrb. Chem. Geol. iii. 630;,
~Reusch,Poggendorfs Ann. cxxii.94; Lange,
Halbedelsteine, $c., 1868 ; Hamilton, Q. J.
Geol, Soc. iv. 209 ; Billing, The Science of
Gems, 1867; Zirkel, Beschaffenh. Min. u.
Gest. 1873, 108 ; Rupert Jones, Proc. GeoL
Assoc. iv. 439 ; Rudler, Pop. Sci. Rev. xvi.
1877, 23.
AGATHISTE'GIA, D'Orb.— An order of

AGLAOPIIENIA.

AIR.

Foraminifera in D'Orbigny's classification
(1825). It may be said to comprise Cor-
ttitsjrira, Miliola (subgenera Uniloculina,
Jji/oculina, Triloculina, Quinqueloculina, Spi-
rolocuUnO) GructtocvUna), Hauerina, and
Fabularw, members of the family Miliolida,
as established bv Carpenter. The peculiar
ball- of- thread-like folding of the segments,
whence the name, is constant in the three
last-named genera; but in Cornuspira it is
merged in a discoidal spire at an early stage
of growth.

BIBL. D'Orbigny, Foram. Ciiba, p. 145 ;
Foram. Canaries, p. 140 ; Foram. Amerie.
p. 68 ; For. Foss. Vienn. p. 255 j William-
son, Brit. Foram. p. 78, &c. ; Carpenter,
Int. Foram. p. G6.

AGA'VE. See FIBROUS STRUCTURES.

AGLAOPHE'NIA, Larnx (Pfr.).— A
genus of Polypi, of the family Plumula-
riidae. It consists of Phimularia crixfata,
myriophyllnm, and pennatula (Johnston).
See PLUMULARIA.

BIBL. Hincks. Brit. Hydr. Zooph. p. 284,
pis. 63 & 64.

AGLAOS'PORA, De Notaris.— A genus
proposed for Spharia profusa, on account of
the asci containing only 4 sporidia ; but
Tulasne has extended it to some species
with eight sporidia, on account of the rela-
tion of the pycnidia to the perithecia. The
brown spores of A. prof lisa, which is not
uncommon on Robinia pseudacacia, are
beautiful microscopic objects.

BIBL. Tulasne. Sel. Fung. Carp. ii. p. 158.

AGO'NIUM, (Erst.— A genus of Con-
fervoid Algae, fam. Oscillatoriaceae.

Char. Filaments very slender, rigid,
flexuous, tufted, jointed ; a single sporidium
in each joint.

A. centrale (PL 3. fig. 1). Marine ; 3-
6'" long; attached to stones.

BIBL. Rabenhorst, Alg. ii. 160.

AG'RION. — A genus of Neuropterous
Insects. See LIBELLULID-E.

AGY'RIUM, Fr.— A genus of Lichena-
ceous Lichens, tribe Graphidei.

1 sp., A. rufum. Thallus forming
whitish spots; a'pothecia bright red. On
old posts.

BIBL. Leighton, Lick. Fl., p. 392.

AINAC'TIS, Kiitzing.— A genus of Os-
cillatoriaceous plants growing on stones in
alpine streams. The two known species
have been found in Britain.

A. alpina. Fronds from 1-12 to 1-2" in
diameter, often confluent, formed of re-
peatedly dichotomous filaments, dark olive

green, containing separate particles of car-
bonate of lime. Hassall, Brit. Fr. Alijrr,
Ixv. 1. 4; Kutz. Tab. Phyc. vol. ii. pL 68.
1 ; Zonotrichiu hatmatites, Rabenhorst, Ala.
ii. 212.

A. cakarea, Kiitz. Fronds 1-4 to 1-2"
in diameter, orbicular, convex, ultimately
confluent, sometimes greenish, often dark
chestnut, composed of dichotomous fila-
ments, at length incrusted continuously \\ith
carbonate of lime. Kiitzing, /. c. pi. 63. 2 ;
Z. calc. Rab. ; Lithonema calcaria, Hassall,
tab. Ixv. fig. 2.

Kiitzing states that the gelatinous sheaths
of the filaments of A. alpina have a spiral-
fibrous structure. See SPIRAL STRUC-
TURES.

AIR. — It need scarcely be remarked that
the air consists essentially of a mixture of
two gases, oxygen and nitrogen, in the pro-
portion by volume of about 21 parts of the
former to 79 of the latter, with variable
quantities of gaseous carbonic acid (about
l-2000th) and aqueous vapour. As the
component molecules of gases are invisible
with any powers of the microscope, the air
possesses no microscopic characters. In two
respects, however, the study of the air is of
great importance : — 1st, in regard to the op-
tical appearances produced by the passage of
light through it when contained in bodies
submitted to microscopic examination ; and
2ndly, in regard to the particles which are
always, in greater or less numbers, sus-
pended in it.

In microscopic investigations, we meet
with air either existing in cells or cavities
in various tissues, or in the form of bubbles,
confined by the liquid in which the objects
are usually immersed. When surrounded
and confined by liquid, it mostly assumes a
spherical form, in accordance with the law
of hydrostatics, that the pressure of fluids
is equal in all directions ; sometimes the
spherical form is exchanged for that of a
compressed or oblong spheroid, the result of
the pressure of the glass slip covering the
object. When confined, in cells or cavities,
it assumes the form of these. It is in ge-
neral easily recognized by transmitted light
from the smooth and even darkness or
shading given to its margins, whilst in the
centre it appears luminous and clear. Some-
times the dark margins of air-bubbles have
a pale purplish-yellow, blue or greenish
tinge. By reflected light, of course, no dark-
ness is produced, but it then appears vitre-
ous and shining, in consequence of the re-

AIR.

AIR.

flection taking place from its surface. So
long as air-bubbles or confined portions of
air are large, the optical appearances above
described are sufficiently characteristic ; al-
though should any doubt exist as to the
nature of a supposed accumulation of air,
the latter must be displaced, either by pres-
sure between two slips of glass, or by im-
mersing the object in which it exists in some
liquid and applying heat. When, however,
air is confined within very minute cavities,
especially when these possess definite forms,
the clear centre is frequently no longer to
be detected, the whole appearing perfectly
black and solid; and serious errors have
arisen from inattention to this circum-
stance, as explained in the Introduction
(p. xxxv).

The corpuscles of dried bone were thus
formerly considered solid bodies, as their
name implies, and as consisting of calcare-
ous matter, until it was found that they
could be filled with a liquid. In all cases,
then, where absolute certainty is required
of the nature of an apparent air-bubble or
accumulation of air, attempts should be
made to displace the mass, either by pres-
sure or prolonged immersion in a liquid,
especially with the aid of gentle heat.

The appearance presented by air con-
tained in tissues, is easily studied in a dry
section of any kind of pith or other vege-
table structure, such as elder-pith, rice-
paper, or cork ; cork is really heavier than
water, and owes its lightness to the air it
contains. On immersing these in water,
this liquid soon enters the lateral cells, but
long digestion is required before the in-
ternal cells become filled with it and the
whole of the air is displaced. Soaking in
alcohol before immersion in water greatly
facilitates the displacement of the air.

The determination of the actual nature,
as regards chemical composition, of air con-
fined in tissues, is a matter of difficulty
where the quantities are microscopic. The^
nitrogen can only be detected by its nega-
tive properties to reagents. The presence of
oxygen might be determined by moistening
a section of any structure with recently
boiled distilled water and then placing it in
a cell containing a solution of protosulphate
of iron, or an alkaline pyrogallate, and im-
mediately sealing the cell with varnish and
allowing the action to continue for some
time.

For the detection of CAEBONIC ACID, see
that article.

There is yet a source of fallacy in the
detection of air imprisoned in structures
where these are of a hard resisting nature,
as in mineral bodies. An illustration of this,
with the method of its avoidance, is given
under TOPAZ, and ROCKS.

In regard to the solid particles present
in, or subsiding from the air, and forming
dust, these consist principally of the spores
of fungi, lichens, mosses, and algae, pollen,
the detritus of the soil, fine fragments of
vegetable and animal fabrics accidentally
separated and diffused during the ordinary
operations of every-day life, the dried but
not dead bodies of infusoria, crystals, and
metallic particles, and the ova of the lower
members of the animal kingdom. The kind
of bodies present in the air varies according
to the locality ; thus in cities, the dust con-
sists mostly of fragments of products of
manufactures, with the spores of fungi,
mixed with particles of carbon or soot, the
ova of the lower animal forms being com-
paratively few and belonging to a limited
number of species ; whilst in open places in
the country, a more ready diffusion of the
spores of plants and the ova of animals
takes place, and the sources from which
fragments of textile fabrics are derived are
less numerous.

The inorganic particles deposited from
the air, consist of fine grains of sand, wafted
from the soil by winds, and rarely fall other-
wise than near the currents by which they
are borne. They are easily recognized by
their angular forms, their resistance to com-
pression, and their not being destroyed or
decomposed by exposure to a red heat.
Certainty as to their composition can only
be obtained by chemical analysis. See
SAND.

The organic forms deposited from the air
formerly gave rise to much perplexity. It
has long been known that when solutions of
various organic substances, or liquids con-
taining these matters undergoing sponta-
neous decomposition, were exposed to the
air, the liquids were soon found to teem
with life — infusoria and fungi, according to
the nature of the decomposing matter,
being discovered in them in abundance. It
seemed very natural to conclude that these
derived their origin from the substances
undergoing decay ; and it i« not to be won-
dered at, that the fact should have given
rise to the conclusion that here was evidence
of the spontaneous or equivocal generation
of animals.

AIR.

AIR.

This theory has now ceased to "be acknow-
ledged ; and a common source of fallacious
reasoning lies in overlooking the fact, that
the air contains the germs of numerous or-
ganic forms, still capable of resuming their
active vitality when they meet with the
requisite conditions. Of this we have con-
vincing proof. For, if the liquid containing
the decomposing matters be heated to ebul-
lition for some time in a bottle or other
vessel, into the cork closing which two
bent tubes are inserted, and, after the air
has been completely displaced by thevapour,
the fresh air admitted be previously passed
through red-hot tubeSj or Pasteur's filter of
cotton-wool, organisms cease to be met with,
and the decomposition of the substance and
growth of the organisms no longer take
place, even in an indefinite period. That
the liquid in these cases does not experience
alteration rendering it incapable of sup-
porting the life of the animal forms intro-
duced, is shown by subsequently admitting
ordinary air, when the organisms appear as
rapidly as in fresh liquids.

Vegetable forms are also constantly met
•with as deposited from the air. In them,
the spores are probably alone the bodies by
means of which the diffusion of the lower
plants by the agency of the air is effected.
Minute fungi are frequently found, like the
animalcules above alluded to, in various
vegetable and animal liquids undergoing
fermentation and decomposition. The ques-
tion of the relation of these fungi to the
processes will be found discussed under
FERMENTATION and PUTREF ACTION ; and
the various genera and species found in dif-
ferent kinds of liquids are treated of under
the heads of these liquids. Fungi and algae
are also met with as parasites and ento-
phytes upon and in living animals : for an
account of these, see PARASITES.

The lower forms of fungi are frequently
found growing upon surfaces from which
they can derive.no nourishment, as upon
slips of glass, window-panes, £c. In these
cases they must derive their nourishment
from the atmosphere. When found in these
situations, however, they soon cease to grow
by subdivision of cells or gemmation, but
speedily form spores. The most common
ones in these situations are the sugar-fun-
gus-— Penicillium glaucum and Aspergillus
penicillatus, Mucor, &c.

The method of distinguishing whether
any minute particle deposited from the
air is of animal or vegetable nature, is de-

scribed under TISSUES, ANIMAL and VE-
GETABLE.

Organic bodies derived from the air are
sometimes met with in snow and hail.
See SNOW and HAIL.

The air has frequently been examined in
regard to the presence of animal or vege-
table organisms, which might account for
the production of epidemic and infectious
diseases ; but the residts obtained in this
direction have not been very satisfactory.
Yet as, on adopting the principle of Pasteur's
filter, and the use of germicides in the
treatment of wounds, and in purifying the
air when infectious diseases prevail, most
decided benefit has been shown to result,
the further examination of the air may allow
of the detection in it of the germs of
disease which have probably been too often
passed over as mere granules, globules, &c.
of no import. The best plan of making
these experiments is to connect a glass tube,
twice bent at right angles, with an aspi-
rator : the free end of the tube should be
drawn to a fine point; and just above this
the tube should be blown into a bulb. The
point is then immersed in a small quantity
of pure water, and the water allowed to
run very slowly from the aspirator. The
water is then slowly drawn into the tube,
and the air is washed as it passes by the
water in the bulb. When a large quantity
of air has been washed by the water, the
latter is shaken briskly and allowed to run
into a clean glass for examination.

Another method consists in closing, by
fusion, the end of a glass funnel, filling
this with ice, and collecting the drops of
water condensed from the air on its ouside,
in a receptacle placed beneath. See Micno-
ZYMES and SCHIZOMYCETES.

Pouchet and Maddox have devised other
forms of apparatus for this purpose.

The appearances presented by air as exist-
ing in cell-cavities is represented in PI. 47.
fig. 23 a, in the delicate cavities of a hair
in PL 29. fig. 1 ; and the lower part of the
same figure represents a portion from which
the air has been displaced by liquid.

BIBL. Pasteur, Ann. d. Chim. 1862, p. 64,
& Sur les corpuscles organises de Tair, Ann.
d. Sc. Nat. (Zool] 1861, xvi. p. 26; Magnin,
Impaludisme, fyc., 1876; Robin, Micr. 1877,
p. 870; Miquel, Comptes Rendm, 1^79;
Cunningham, Mic. exam, of air, Calcutta ;
Tissandier, Poussieres de Vair ; Pouchet,
Aeroscopie, 1870 ; Tyndall, Lcct. Land. Inst.
(Times, Dec. 12, 1877), & Proc. Roy. Soc.

AIR-BLADDER.

ALARTA.

1878 ; Beauregard & Galippe, Guide fyc.
1880, p. 764 ; Robin, Micr. 1877, p. 870.

AIR-BLADDER of Fishes. See SWIM-
MI XG BLADDER.

AIR-BUBBLES. See Am.

AIR-CELLS or Sacs of animal?.— These
are dilatations or expansions of the air-
passages.

In birds, these are membranous cavities
communicating with the lungs and dis-
tributed through the chest and abdomen.
They extend over almost all parts of the
body, around the joints of the extremities,
into the bones, the quills, and the feathers,
and even between the skin and subjacent
muscles. During inspiration, the air enters
all these cavities.

In insects, the air-cells or sacs consist of
dilatations of the tracheae. See TRACHEJE.

Their obvious use is either to diminish
the specific gravity of the body, or to act as
reservoirs of air during the impeded respi-
ration connected with flight.

BIBL. Siebold and Stannius, Lehrb. d.
vert/I. Anat. ; Owen, Hunt. Led. ; Carpenter,
Compar. Anat. ; Gegenbaur, Vergl. Anat.
1878.

AIR-PASSAGES in plants are large
intercellular passages occurring especially
in the stems of Monocotyledons and in the
leaves and stems of aquatic plants. Their
form and arrangement are sometimes very
regular and elegant, especially when they
depend upon a certain regular peculiarity of
shape in the cells which form the walls of the
passages. Thus cross sections of the com-
mon rush are pleasing microscopic objects,
exhibiting regular stellate cells, the rays of
which are separated by large air-passages,
giving the spongy texture to the structure.
Large air- passages, communicating with the
stomata, are not unfrequently lined by a
cuticular layer similar to that found upon
the external surface of epidermal cells. In
the Nymphceacece (Water-lily Order) the
large air-passages in the floating leaves and
the stem have peculiarly developed star-like
cells projecting freely into these cavities;
these cells are filledVith a granular sub-
stance very unlike the contents of the large
cells of the general parenchyma of the leaf.
Their nature and office are yet unknown.
The partitions separating the air-cells hori-
zontally in Limnocharis PlumierifmdAlisma
plantaoo form beautiful microscopic objects.
The stems of the Equiseta, or Horse-tails,
present a very regular arrangement of per-
pendicular air-passages in the thin walls of

their hollow stems, seen well in cross sec-
tions. See EQUISETACEJE.

AIR-SACS in Plants.— The genus Utri-
cularia, or Bladder-wort, takes its name
from a peculiar structure of its leaves. The
common species, U. vulgaris, L., often found
swimming just below the surface of the
water, in quiet streams, is provided with a
curious floating apparatus, formed by modi-
fication of portions of the feathery leaves,
consisting of small membranous sacs or
pouches, closed by a valve. The opening of
the pouch is somewhat funnel-shaped ; and
the mouth, as also the internal walls of the
cavity, is furnished with curious micro-
scopic glandular hairs. Certain of the cells
contain a blue- colouring-matter, distinct in
its nature from chlorophyll. The valve of
the pouch appears to be capable of opening
inwards only ; so that while it is turgid with
sap, in the vigorous periods of life, it is kept
closed by the pressure of the air apparently
secreted within the pouch ; afterwards the
tissue loses its tension and the air makes
its way out, allowing water to enter, and
thus putting an end to the performance of
the function of the air-sac.

BIBL. Meyen. Secretions- Or q. d. Pftan-
zen, 1837, p. 12, t. 5. figs. 1-6; Goppert,
Bot. Zeit. 1847, p. 721; Benjamin, Sot.
Zeit. 1848; 1 et seq.; Schleiden, Princip.
of Botany, Engl. transl. pp. 77-279; Hen-
frey, Elem. Course (Masters), 1878, p. 523 ;
Sachs, Lehrb. d. Sot., 1874, p. 664.

AIR-TUBES of Insects.— These are horny
tubes found in some insects which live in
w^ater, as the larvae of many Diptera and
some water-bugs (Nepa, Ranatra}. They
are placed either at the first or last ab-
dominal segment. See NEPA, CULEX,
INSECTS.

AIR-VESSELS in Insects, see TRACHEAE.
In plants, see SPIRAL STRUCTURES.

ALA'RIA, Greville. — A genus of Lami-
nariaceae (Fucoid Algse), distinguished by
the superficial fructification, arranged in
definite patches on the surface of special
fronds, something like the sori of Ferns.
The patches consist of sporanges resembling
the thecae of lichens, crowded together and
interposed between perpendicular epidermal
cells. The sporanges of A. esculenta are
described by most authors as pyriformspo/rs
enclosed in a perispore ; but' they perhaps
produce biciliated zoospores like those of
Laminaria. See LAMIXARIA.

BIBL. Harvey, Brit. Mar. Alga, p. 29,
pi. 3 A j Greville, Alg. Brit. p. 25, pi. 4.

ALBERTIA.

C 26 ]

ALBUMEN.

ALBER'TIA.— A genus of Rotatoria.
See ALBERTINA.

ALBERTI'NA.— A family of Rotatoria
(Dm.).

Char. Body, cylindrical, vermiform,
rounded in front, with an oblique orifice,
from which the ciliated organ, scarcely
broader than the body, projects, terminated
behind by a short conical tail. Jaws for-
ceps-like, simple or unidentate.

This family contains only a single genus,
and this a single species, A. vermiculus
(PI. 43. tig. 4), which lives parasitically in
the intestines of worms (JLumbrici) and
slugs (Limaces). Length 1-47 to 1-79".

Within the body are seen- ova and young
in various stages of development. The
ciliated apparatus in front of the mouth is
surmounted by a hood-like appendage.

ALBU'MEN (Chemical).— A proximate
principle of animal and vegetable bodies,
with which we are familiar as occurring in
the white of egg. It exists in two states,
uncoagulated and coagulated. At a tempe-
rature of 160° F. it is reduced from the
former into the latter condition. It is
reddened by Millon's test ; is insoluble in
acetic acid ; is rendered purple by Petten-
kofer's test, but the reaction requires some
time for its production. In the coagulated
state it is distinguished from fibrine by the
action of acetic acid, and by its insolubility
under prolonged digestion at a heat of
110° F, with solution of nitrate of potash.
When heated with strong muriatic acid, it
is coloured purple.

It possesses no microscopic characters;
when coagulated, it appears to consist of
extremelv tine amorphous granules.

ALBUMEN, or PERISPERM (of seeds).
— This is a technical term used in Botany to
denote the cellular structure which exists in
greater or less quantity in all seeds where
the development of the embryo is not accom-
panied by the entire absorption of the
nucleus of the ovule. When the embryo
does so displace the nucleus, it becomes
immediately invested by the seed-coats ; in
other cases it is found imbedded in a mass
of cellular tissue of varying structure, which
is the t albumen.' The structure of albumen
corresponds to that of the cotyledons of seeds
devoid of albumen, both serving the same
office, namely that of reservoir of nutriment
for the germinating seed. This nutriment
may be laid up in different conditions —
namely, in the state of starch, oil, aleurone,
or of cellulose, and in the last case in a soft

and fleshy, or a hard and horny condition.
Combined conditions are often met with in
the same structure, as when a fleshy tissue
contains starch or oil in the cavities of its
cells, &c.

Starchy, mealy, or farinaceous albumen
constitutes the chief part of the seeds of
many plants, especially of those of the Grass-
tribe, and is that portion of the corn-grains
whence white flour is obtained. Here the
cellular tissue is composed of membranous
cells densely filled with starch-grains (P1.46.
fig. 3). The edible portion of the cocoa-nut
is the corresponding region of that seed, and
affords us a good example of an oily albu-
men, composed of tolerably thick-walled
cells filled with a viscid mucilage, in which
numerous oil-globules are suspended. The
stone of the Date, the nut of the Areca
Palm (PI. 47. fig. 21), are good examples of
a horny albumen, the cells possessing walls
of extreme thickness, traversed by pores and
formed, like wood-cells, by the deposition of
successive layers. In the ripe seed the
structure of this horny albumen is generally
much disguised, and a section exhibits the
appearance of a homogeneous horny sub-
stance excavated into irregular cavities. By
applying dilute sulphuric or sulpho-chromic
acid, the true boundaries of the cells may
generally be distinguished, and often even
the lamination of the walls (PI. 47. fig. 22).
The substance called Vegetable Ivory is the
albumen of the seed of the Phytelephas
Palm, and is an instance of an extreme de-
gree of development of the cellulose albumen,
vying with the hardest woods in the solidity
of its cell-walls, A thin section of this albu-
men, especially if treated with acid, at once
reveals the cellular structure of this dense
substance (PI. 47. fig. 23). The true struc-
ture may also be detected by the help of
polarized light (see POLARIZATION). The
cotyledons of many seeds are, as above
stated, formed of elementary structures
resembling those of albumen. We find
them farinaceous, fleshy, or oily, but rarely
attaining to a very great degree of solidity
in the horny forms. The cotyledons of beans
are composed of a fleshy cellular tissue
with thick, porous walls, coloured blue by
iodine alone (amyloid), while the cavitie's
of the cells are tilled with starch-grains.
The cotyledons of the almond, nut, &c.
are examples of fleshy cells containing
abundance of oil-globles.

The albumen of seeds may be formed by
the development of the tissue of the nucleus

ALCYONELLA.

[ 27 ]

ALDERIA.

of the ovule, in which case it is distinguished
by some botanists as the epispenn ; gene-
rally it is formed from the cell inside the
embryo-sac, the latter expanding to dis-
place the nucleus which becomes absorbed ;
such albumen is called endosperm. Some
seeds, such as those of the Nymphaeaceae,
Piperacae and others, have both endosperm
and episperm, i. e. albumen formed inside
and outside the embryo-sac. The term
perisperm is often (advantageously) substi-
tuted for albumen, which has "quite a different
signification in physiological chemistry.

The albumen of seeds is examined by
means of fine sections. In the horny or
bony seeds, the application of solution of
potash or nitric acid is very serviceable in
ascertaining the true cellular structure.

BIBL. Schleiden and Vb'gel, Nova Acta,
1838, xix. p. 52 (plates) ; Sachs, Botanik,
1874, p. 681; Henfrey, Bot. (Masters),
1878, p. 154.

ALC YONEL'LA.— A genus of _ fresh-
water Polyzoa (Bryozoa), belonging to
the order Hippocrepia and family Pluma-
tellidae.

Char. Tubes branched, adherent to each
other by their sides ; orifices terminal ; ova
(statoblasts) presenting an outer ring, but
free from spines.

Polypary (polypidom) incrusting, and
forming a sponge-like brown or greenish
mass, attached to submersed wooden posts
&c.

A, stagnorum (fungosa), PL 41. fig. 3.
Polypary indefinite ; orifices of tubes entire,
and without a furrow. Rare.

A. Benedeni. Polypary indefinite ; tubes
emarginate at the orifice, and furnished with
a longitudinal furrow. Rare.

A.flabellum. Polypary fan-shaped ; tubes
prostrate, with a furrow. Rare.

BIBL. Johnston, Brit. Zooph. p. 391 ; All-
man, Polyzoa (Ray Society), p. 86 ; Nitsche,
Mull. Archiv, 1868.

ALCYONIDTIDy£(Halcyonellea, Ehr.,
Johnston). — A family of marine Polyzoa
(Bryozoa) of the order Infundibulata, and
suborder Ctenostomata.

Char. Polypary sponge-like, fleshy, of
irregular form; cells irregularly arranged,
immersed, with a contractile orifice ; no ex-
ternal ovarian capsules. Genera : —

Alcyonidium, Lamx. Erect; lobed or
simple ; cells pentagonal.

Cycloum, Hass. Incrusting, covered
with imperforate papillae ; eggs in circular
clusters.

Sarcochitum, Hass. Incrusting, covered
with perforate prominences in which the
cells are immersed; eggs scattered singly
throughout the polypidom.

BIBL. See the Genera.

ALCYONLD'IUM, Lamx.— A genus of
Infundibulate Polyzoa (Bryozoa), of the
suborder Ctenostomata, and family Alcy-
onidiidae.

Char. Erect, lobed, or simple ; cells im-
mersed, pentagonal.

Nine British species ; they occur attached
to marine objects by a narrow base.

A. gelatinosum. Lobed, lobes subcylin-
drical, surface smooth; attached by a nar-
row base. Deep water.

A. hirsutum. Lobed, compressed, surface
papillar from partial protrusion of the
polype-cells. Common.

A. parasiticum. Incrusting, earthy, sur-
face porous.

BIBL. Johnston, Brit. Zooph. p. 358;
Gosse, Mar. Zool. ii ; Hassall, Ann. N. Hist.
vii. p. 370 ; Reid, ibid. xvi. p. 393 ; Hincks,
Polyzoa, 1880, p. 490.

ALCYO'NIUM.— A genus of Ccelente-
rata or Zoophytes, belonging to the order
Anthozca, and family Alcyonidse,

Char. Polype-mass lobed or incrusting,
spongy, containing scattered calcareous
spicula. The skin (ectoderm) coriaceous,
marked with stellate spores ; interior gela-
tinous, netted with tubular fibres and per-
forated with longitudinal canals termina-
ting in the polype-cells, which are subcuta-
neous and scattered. Polypes exsertile.
Marine.

A. digitatum (spicula, PL 41. fig. 28).
Commonly called 'dead man's toes or
fingers,' and cows' paps. Form of poly-
pidom variable, greyish -white or orange-
coloured, skin somewhat wrinkled, stud-
ded over with stellate pores, even with the
surface.

Very common, so that on many parts of
the coast scarce a shell or stone can be
dredged from the deep that does not serve
as a support to one or more specimens.

A. glomeratum. Colour deep red ; rare.

BIBL. Johnston, Brit. Zooph. p. 174;
Gosse, Mar. Zool. ; Gray, Ann. N. Hist.
1869, v. p. 117.

ALDE;RIA, Pritchard. A doubtful

nus of animals discovered by Alder.

The body of one species (PL 49. fig. 14)
consisted of a vase- or cup-form, expanded
at the top and furnished with numerous
pointed tentacles, abruptly thickened to-

ge-

ALECTO.

ALGM.

wards the base and forming more than one
row. Body attached to a Sertularia by a
tolerably stout stem.

A second species was rather smaller, body
ovate, with a very slender and shortish
stem ; tentacles capitate, not so numerous as
in the first species, and placed in a single
row round a narrow disk.

This was also found on a Sertularia.

A third (PL 49. fig. 15) was found in
fresh water. Body pear-shaped or, rather,
bell-shaped, with a distinct rim, and a single
row of delicate capitate retractile tentacles ;
stem long and slender. They come nearest
to the genus Acineta. Similar organisms
have been observed by Str. Wright.

BIBL. Trans, of Tyneside Naturalists'
Field Club, i. p. 365 ; Ann. N. Hist. vii.
p. 426 ; Pritchard's Inf. p. 562.

ALECTO, Lamx. (Stomatopora). — A
genus of marine Polyzoa, of the suborder
Cyclostomata and family Tubuliporidse.

The species are found upon old shells and
stones from deep water.

A. granulata. Cells in one or occasion-
ally two rows, their walls granular.

A. major. Cells in more than one or two
rows, their walls smooth.

A. dilatam. Branches of polypary dila-
ted at the ends j cells in several rows, their
walls granular.

Nine other species.

BIBL. Johnston, Brit. Zooph. p. 280 j
Busk, Cat. of Mar. Polyz. (Brit. Mus.) ;
Hincks, Polyzoa, 1880, p. 424.

ALECTO'RIA, Acharius.— A genus of
Lichens, fam. Lichenacei. Six British
species j on alpine rocks.

BIBL. Leighton, Lichen-Flora, 1879,
p. 77.

ALETJ'RONE (Gluten-flour).— This or-
ganized cell-substance, like starch, is very
generally diffused through the vegetable
kingdom, occurring in the endosperm and
cotyledons of most seeds. It exists in large
quantity in castor-oil and lupine seeds, in
nuts, almonds, cocoa, and coflee-beans &c. It
was long overlooked, on account of its solu-
bility in water. In starchy seeds it consists
of minute granules, of a spherical form,
often pitted on the surface, either solid or
hollow, and covered by a membrane ; while
i:i oily seeds, the grains are larger and more
complex. They are insoluble in ether, al-
cohol, and fixed oils, but soluble in water,
dilute acids, and alkalies. They are coloured
deep yellow by iodine, and intense red
by carmine-solution. Nitrate of mercury

renders the interior brick-red, but does not
colour the wall. Each granule consists
principally of albuminous matter, but also
contains gum and sugar. In many oily seeds,
as castor-oil, Brazil nuts, &c., the aleurone
grains contain a crystalloid and a globoid
body. The crystalloids possess angular forms,
and so resemble crystals ; they are not dis-
solved by water or acids, but swell in Liq.
Potasses, and are coloured yellow by iodine.
The globoids are small rounded masses, not
crystalline, but composed of phosphate of
lime and magnesia: they are soluble in acids,
but not in alkalies. Sometimes crystals of
oxalate of lime are also met with in the
grains. Aleurone is usually colourless, some-
times green, as in pistachio-nuts, yellow in
Ailanthus-seeds, or blue. It is most easily
examined in a thin section of an almond or
castor-oil seed immersed in oil or spirit.

Fig. 6 b.

Magnified 400 diameters. Magnified 800 diameters.

* Pisum sativum, the garden pea ; showing the small
grains of aleurone, and the large starch -grains.

** Cell of Eicinus communis, showing the granular
protoplasm with oil-globules, and the ovoid aleurone-
grains, containing the round globoids and the angular
crystalloids.

The nutritive properties of many seeds,
as peas, nuts, almonds, &c., depend to a
considerable extent upon the presence of
aleurone. Arid the solubility of aleurone in
water is a point of great consideration in re-
gard to the formation of dietary tables. For
if, in boiled peas for instance, the nitroge-
nous proportion is calculated according to
that naturally existing, and the liquor be not
consumed, the diet will be deficient in that
principle to a corresponding degree.

BIBL. Hartig, Bot. Zeit. 1857 j Wiesner,
Techn. Mikr. p. 74, 1867 ; Sachs, Bot. p. 52.

ALG^E, Sea-weeds $c. — This class of
Thallophytes includes the Sea-weeds and
the multifarious green vegetable forms of

ALG.E.

[ 29 ]

ALG^E.

simple cellular structure met with in all
streams, ditches, ponds, or even the smallest
accumulations of fresh water standing for
any length of time in the open air, and com-
monly on walls or the ground in all perma-
nently damp situations. The great variety
of conditions of organization, all variations
as it were on the theme of the simple vege-
table cell, produced by change of form,
number, and arrangement of this simple
element, renders the Algae peculiarly inter-
esting as objects of microscopic research,
even in regard to morphological conditions
alone.

This simple condition of the structures is
here, as in other cases, accompanied by a
delegation of the physiological functions
most completely and fully to the individual
cells ; that is to say, the marked difference of
purpose seen in the leaves, stamens, seeds,
&c. of the flowering plants is absent here,
and the structures carrying on the operations
of nutrition and those of reproduction are so
commingled, conjoined, and, in some eases,
identified, that a knowledge of the micro-
scopic anatomy is indispensable even to the
roughest conception of the natural history of
these plants. Added to this, we find these
plants of such simple structure that we can
see through, and through them while living
in a natural condition, and by means of the
microscope penetrate to mysteries of orga-
nization either altogether inaccessible, or
only to be attained by disturbing and de-
structive dissection, in the higher forms of
vegetation.

This Class comprehends a vast variety of
plants, exhibiting a wonderful multiplicity
of forms, colours, sizes, and degrees of com-
plexity of structure ; but the subdivision of
them into three groups, characterized by
striking external characters, which are
adopted in the classifications of some of the
leading Algologists, facilitates the cursory
consideration to which we are confined here.
These three Orders are iheHed-spored Algce
(FLOBIDE^E or RHODOSPORE^E),thel)«r&-
spored Alga (MELANOSPORE^E or Fu-
COIDE.S:), and the Green-sporedAlgcz (CON-
FER VOIDED, or CHLOROSPOREJE) — the first
two consisting almost exclusively of Sea-
weeds, the last of marine and more especi-
ally of freshwater plants, the majority of
which are microscopic when viewed singly.

The Algae are differently distributed by
Thuret, whose researches on their fructifica-
tion have thrown so much light upon this
class, also by Rabenhorst and Sachs, whose

views are referred to under the Orders, and
VEGETABLE KINGDOM.

Order 1. FLORIDEJE or RHODOSPORE^E.
Almost all marine plants, with a leaf-like or
filamentous rose-red or purple, rarely brown-
red or greenish red, thallus. Fructification
appearing in three forms : — 1. spores, con-
tained in external or immersed definite
masses, mostly enclosed in conceptacles or
cystocarps (ceramidia, coccidia, favellidia,
&c.) ; 2. tetraspores or tetragonidia, red or
purple, either external or immersed in the
frond, rarely contained in proper concepta-
cles (stichidia), each consisting of a trans-
parent membranous sac containing, when
ripe, four spores ; 3. antheridia, pellucid sacs
filled with yellow motionless spherical cor-
puscles, collected in masses in situations
corresponding to the spore-fruits. Fertiliza-
tion is effected through the agency of a
style-like filiform process or trichogyne,
with which the spermatozoids copulate. The
trichogyne is either only the prolongation
of the cell in which the spores are produced ;
or, more generally, it is supported upon
small cells, which take no direct part in the
formation of the spores. See FLORIDE;E.

Order 2. FUCOIDE.E or MELANOSPORE^B.
Marine plants with a leaf-like, shrubby,
cord-like or filamentous thallus, of olive-
green or brown colour. Fructification very
varied : — 1. in Fucaceae consisting of mon-
oecious or dioecious conceptacles or oogonia
containing sporanges and antheridia, the
spores being fertilized by spermatozoids after
the discharge of both from the pa,rent ; 2. in
Laminariaceae and allied orders consisting
of definite or indefinite collections of
clavate or filiform sporanges, producing
biciliated zoospores, which germinate di-
rectly ; 3. in Cutleriacese of similar spo-
ranges producing zoospores, together with
antlieridia, like those of Fucaceae ; 4. in Dic-
tyotaceae presenting three forms resembling
those of Florideae, viz. collections of tetra-
spores, of sporanges containing simple spores,
and of antheridia. See FUCOIDE^E and

Order 3. CHLOROSPOREJE or CONFER-
VOIDEJE. Plants growing in sea or fresh
water, or on damp surfaces, mostly green,
with a filamentous, or more rarely a leaf-like,
pulverulent or gelatinous thallus ; the last
two forms essentially microscopic, consist-
ing frequently of definitely arranged groups
of distinct cells, either of ordinary structure
or with their membrane silicified (Diato-
maceae). The green colouring matter con-

ALG^E.

C 30 ]

ALKALOIDS.

sists simply of chlorophyll in one group,
forming the Chlorophyllophycete of Raben-
horst, as the Desmideae, Confervse, &c.
While in the other, it exists combined with
Phycocyanine, giving it a bluish tinge ;
these forming the Phycochroniophyceae of
Rabenhorst,the Cyanophyceae of Sachs, as in
the Oscillatoriaceae,Nostochaceae, andRivu-
lariaceae. Fructification varied in its details,
but essentially reducible to three forms : —
1. resting spores produced from the cell-
contents after fertilization, either by CONJU-
GATION or impregnation by (2.) spermato-
zoids produced from the contents of other
cells ; 3. zoospores, 2-, 4-, or multi-ciliated
active gonidia, discharged from the vegeta-
tive cells without impregnation and ger-
minating directly ; in some instances these
conjugate (CONJUGATION). The simple
vegetative increase of the Unicellular forms
is a process essentially analogous to the
cell-division of the filamentous forms, but
results necessarily in multiplication of the
species. The Volvocineae are remarkable
for their passing the vegetative stage of
existence in the form of ciliated zoospores,
mostly collected within a gelatinous common
envelope, or coenobium, into a definitely
arranged family. See CONFERVOIDE^EJ.

Some Algae have been found fossil. (See
AGATE.)

Excluded families of Algaa : —

CBYPTOCOCCE^, Kg., containing the
genera Cryptococcus, Kg., Ulvina, Kg., and
Sphcerotilus, Kg.

LEPTOMITEJE, Kg., containing the genera
Hygrocrocis, Ag., Sirocrocis, Kg., Leptomi-
tus, Ag., ArthromituSy Leidy, Cladophytum,
Leidy, Mycothamnion, Kg., Erebonema,
Romer, Chamcenema, Kg., Nematococcus,
Kg., Chioniphe, Thienemann, Moulinea, Ch.
Robin, Enterobryus, Leidy, JEbertno, Leidy.

PH^ONEMEJE, containing the genera
Stereonema, Kg., Phceonema, Kg., Phceosi-
phonia, Kg.

These consist, for the most part, of aqua-
tic states of MUCOBINI, or of SCHIZOMY-
CETES.

BIBL. Harvey, Brit. Algce, 2nd. ed. 1849 ;
Phycol. Britann. ; C. Agardh, Syst. Alg. ;
J. Agardh, Species fyc. Algar. ; Kiitzing,
Phycol. generalis ; Sp. Alg. ; Tabula Phyc. ;
Phycol. Germ. ; Lyngbye, Hydrophytoloyia
Danica ; Greville, Alga Brit. ; Berkeley,
Crypt. Bot. p. 84; Henfrey, Elem. Bot.
(Masters) ; Thuret, Ann. d. "Sc. Nat. 1855 ;
Sf Etudes Phycologiques (Anal. d. Algues
marines), 1878 ; Rabenhorst, Flora Earop.

Fig. 7.

Algarum, 1865 ; Bornet and Thuret, Ann.
d. Sc. Nat. 1867, vii. p. 166 (Ann. N. Hist.
1867, xix. p. 35), $ Notes Algologiques, 1876;
Sachs, Lehrb. d. Bot. 1874; Wright, Spicil.
Phycolog. 1879.

ALICULA'RIA, Corda.—
A genus of leafy Liverworts
(see JUNGEBMANNIE^:), con-
taining one British species,
common on hedge-banks.

A. scalaris=Jungermannia
scalaris, Schrad., J. lanceolata,
Eng. Bot. (fig. 7).

Jnngerm. compressa, Hook.,
which has stipules only on the
innovations, is included in this Alicularia scala-
genus by Fries and others. ris. immature

BIBL. Hooker Brit. Jun- gSSP^f
germanmce, pi. 61 ; Sowerby, gone (magni-
Engl. Bot. pi. 605. "M).

ALKALOIDS.— The utility of the micro-
scope in distinguishing the more common
alkaloids from each other, has been shown
in an able paper by Dr. Anderson. The
characters consist in the crystalline form of
the alkaloids, and in that of their sulpho-
cyanides.

The alkaloids are dissolved in dilute
hydrochloric acid, and the dilute solution
mixed, on a glass plate, with solution of
ammonia of moderate strength if the alka-
loid itself is to be examined, or with a
strong solution of the sulphocyanide of
potassium if the sulphocyanide is required,
and at once placed under the microscope.
The only precaution requisite is to avoid
having the solution too concentrated, as the
crystals are then less well-defined than if a
dilute solution is employed.

The power employed should be 250 dia-
meters ; for if a very high power is used, the
form of the crystals is not so readily distin-
guished.

Atropine is precipitated in the amorphous
state by ammonia, and not at all by the
sulphocyanide of potassium.

Brucia. A salt of brucia in a sufficiently
dilute state, mixed with ammonia, does not
give an immediate precipitate ; but in the
course of a very short time, irregular star-
like groups of pointed crystals are observed,
as in PL 11. fig. 1 a. Sulphocyanide of potas-
sium produces a precipitate in tufts of ex-
tremely thin and feathery crystals, which
either radiate from a centre, or present a
sheaf-like appearance. The latter form,
however, is much better marked in the
crystals deposited after some hours from a

ALKALOIDS.

ALONA.

dilute solution, which are still microscopic,
although somewhat larger than those repre-
sented in the figure (PL 11. fig. 1, 6).

Cinchonine is obtained by precipitation
with ammonia in the form of minute granular
masses, made up of more or less distinctly
acicular crystals, radiating1 from a centre. It
is, however, somewhat difficult to obtain
them well-marked ; and they not unfrequently
appear as a confused mass of granules, in
which the radiated structure is very imper-
fectly seen. They form best when the solu-
tions are rapidly mixed (PI. 11. fig. 2). With
sulphocyanide of potassium, cinchonine gives
a precipitate consisting of six-sided plates,
together with a variety of irregular crystal-
line masses, and a few rectangular plates
(PI. 11. fig. 3). When formed by mixing
in a test-tube with agitation, and allowing it
to stand for some time, the crystals are still
microscopic, but much more definite, and
sometimes consist almost entirely of isolated
six-sided tables, of great regularity. The
precipitate dissolves readily in hot water,
and is deposited as the solution cools, in
irregular plates.

Narcotine is precipitated by ammonia in
branched groups of pointed crystals (PI. 11.
fif£. 4). In concentrated solutions a preci-
pitate is thrown down by sulphocyanide of
potassium, which dissolves readily in hot
water, and is again deposited on cooling.
Under the microscope it is perfectly amor-
phous.

Strychnine. The hydrochlorate, treated
with ammonia, gives an immediate precipi-
tate, consisting of minute prismatic crystals,
all nearly of the same size and very well
defined. Most are isolated, but some cross
each other at an angle of about 60°. When
lying in one position, they exhibit more or
less an appearance of a Saint Andrew's
cross, with a peculiar arrangement of
their terminal facets (PI. 11. fig. 5.) The
sulphocyanide consists of flattened needles,
sometimes single, but generally in irregular
groups, as in PI. 11. fig. 6. They are either
terminated by a blunt acumination or are
truncated. Those precipitated on the large
scale present the latter forms.

Morphia. Ammonia does not produce an
immediate precipitate in solutions of mor-
phia ; but in the course of a longer or shorter
period, according to the degree of dilution,
crystals form, which gradually increase in
size, and possess the form represented in
PI. 11. fig. 7. Salts of morphia are not pre-
cipitated by sulphocyanide of potassium,

unless the solution is highly concen-
trated.

Quinine. Its solution gives with ammo-
nia a perfectly amorphous precipitate ; with
sulphocyanide of potassium small irregu-
lar groups of acicular crystals, resembling
those produced by strychnia, but longer
and more irregular (PI. 11. fig. 8). When
the precipitate is produced in a test-tube,
and with a concentrated solution, it falls
immediately as a white powder composed
of extremely minute needles; but when
the solution is dilute, it is deposited after
the lapse of twenty-four hours, in crystals
from l-4th to l-3rd of an inch in length.
See QUININE and CRYSTALS.

BIBL. Anderson (T.), Edin. Mn. J. viii.
p. 570.

ALLAN'TOIN.— A crystalline organic
substance found in the liquid of the allantois
and in the renal secretion of the calf &c.
As artificially prepared, it is one of the
products of oxidation of uric acid.

Its crystals form transparent colourless
needles and four-sided prisms, with mostly
dihedral unequal summits, PL 10. fig. 20;
not very soluble in either cold or boiling
water, more soluble in alcohol, but not at
all in ether.

BEBL. See CHEMISTRY.

ALLAN'TOIS. — An oblong or pyriform
sac developed during a veiy early period of
embryonic life from near the end of the in-
testine. Its function is that of a temporary
respiratory organ. The capillaries in the
allantois of the chick are distributed closely
like those of the lungs of the Batrachia.

BIBL. Wagner, P7*ya. by Willis; Miiller,
by Baly ; Carpenter, Hum. Phys. ; Kirkes'
Phys., by Baker.

ALLOMORPHI'NA, Reuss.— One of
Reuss's" Cryptostegian "genera of perforate
Foramiuifera. It has the appearance of an
irregular Miliola ; subtriangular, with the
chambers in a triple spire and overlapping
so much that only the last three chambers
are visible. The aperture is a transverse slit
on the inner border of the last chamber.
Fossil in the Upper Chalk and Tertiary of
Germany.

BIBL/ Reuss, Denks. Akad. Wien, i. 352 ;
H. B. Brady, Qu. Mic. Jn. xix. 67.

ALLOT'RICHA, Kent.— A genus of
Infusoria, of family Oxytrichina.

BIBL. Kent, Infusoria, 1880.

ALO'NA. — A genus of Entomostraca, be-
longing to the order Cladocera and family
Lynceidas.

ALSOPHILA.

ALYCUS.

The three British species may be thus
distinguished : —

, /Shell reticulated reticulata*.

*•' \8hellstriatedorgrooved 2.

( Anterior margin of shell nearly

2 ) straight, shell brown quadrangularis\ .

j Anterior margin of shell convex,

( shell colourless ovata.

PI. 19. fig. 4.

PI. 19. fig. 5.

131,

Alsophila excelsa.
Pinnule with son".

BIBL. Baird, Brit. Eiitomost. p.
pi. 16.

ALSOPH'ILA, B. Fig. 8.

Brown. — A genus of
PolypodiaceousFerns.
Exotic (fig. 8).

Char. Sori globose,
dorsal, on a vein or in
the fork of a vein.
Receptacle mostly
elevated, often vil-
lous. Involucre ab-
sent. Veins simple
or furcate, free.

Arborescent, mostly tropical; species
numerous.

Sections of their petioles exhibit fine scala-
riform ducts, the slits between the fibres
forming many perpendicular rows.

BIBL. Hooker & Baker, Syn. Filic.p. 31.

ALTERNA'RIA, Nees.— A
genus of Torulacei (Coniomyce- Fig. 9.
tous Fungi). Microscopic fila-
mentous Fungi, remarkable for
their flask-shaped, cellular spores,
produced in chains which ulti-
mately break up into the single
links (fig. 9).

A. tennis grows parasitically
upon other filamentous Fungi,
and on decaying gourds, and is
common about Berlin, Prague,
and other places. Corda made ^
the ripe spores germinate on Cla-
dosporium lierbarum kept moist.
They usually first protruded a
filament from the neck or atte-
nuated projection, and afterwards
others from the cells at the sides
and opposite end of the spore. Alternaria
These filaments became branched. Fertile

The Messrs. Tulasue have spore-bear-
shown that Alternaria tennis is j,^? threads
merely a state of the common ma|nifled).
Sphceria herbarum.

BIBL. Corda, Ic. Fung. iii. p. 5, pi. 1.
fig. 16; Prachtfl. europ. Schimmelbild. p. 13;
Tulasne, Fung. Carpologia, ii. pi. 32.

ALTERNATION OF GENERATIONS.
See GENERATIONS.

ALTEUTHA, Baird (Peltidium, Brady).
— A genus of marine Entomostraca, of the
order Copepoda, and family Cyclopidae.

A. depressa (PI. 19. fig. 3). Eye red.
Found in Berwick Bay, but not common.

A. interrupta, common ; A. crenatula.

BIBL. Baird, Brit. Entom. p. 216; Brady,
Copepoda (Ray &>c.), ii. p. 158.

AL'TICA. See HALTICA.

ALU'CITA. — A genus of Lepidopterous
insects, of the family Alucitidae.

The species are remarkable from having
the wings divided into six lobes or rays
which are fringed with long narrow scales
resembling hairs, giving them a beautiful
feathery appearance. They are not uncom-
mon in'gardens, and sometimes enter out-
houses.

The species of Pterophorus exhibit the
same structure, except that the anterior
wings have two, and the posterior three lobes.

BIBL. See INSECTS (Wings).

ALUM. — This well-known substancecon-
sists chemically of potash and alumina, with
sulphuric acid and water. Its crystals belong
to the regular cubic or tesseral system, and
usually assume the octahedral form. When
dissolved in boiling water with slaked lime,
it crystallizes in cubes. The term alum has
recently been extended to those compounds
in which the potash is replaced by other
bases ; thus we have ammonia-alum,
chrome-alum, &c. The crystals exert no
influence upon polarized light. Common
alum possesses but little microscopic
interest. Its solution is used in some of
the preservative liquids.

AL VEOLINA, D'Orb.— A genus of Fora-
miniferalmperforata,of the family Miliolida
(Carpenter), nearly allied to Orbiculina, but
elongated in the direction of the axis ; Or-
biculina being greatly compressed in this di-
rection. Alveolma rotella (D'Orb., sp.), how-
ever, is nautiloid ; AL melo, var. a, Ficlit.
and Moll, is oblately spheroidal ; var. ft,
prolately spheroidal; AL ovoidea, D.'Orb.,
elongate-oval ; AL sahilosa, Montft., fusi-
form ; and AL elongata, D'Orb., is sub-
cylindrical.

A. fmiformis (pi. 23. fig. 15) ; A. rotella
(pi. 23. fig. 16).

BIBL. Carpenter, Phil. Trans. 1850, p.
552 ; Foram. p. 99 ; Parker and Jones,
Ann. Nat. Hist. ser. 3. viii. p. 161.

AL'YCUS, Koch.— A genus of Acarina,
fam. Trombidina.

ALYSCUM.

AMBLYSTEGIUM.

A. roseus. Body papillose.

BIBL. Koch, Uebersicht, &c. ; Murray,
EC. Entom. p. 150 ([tig.).

ALYSCUM, Duj. — A genus of Infusoria,
of the family Enchelia, Duj.

Al. saltans (PI. 30. fig. 8). Colourless,
with faint longitudinal furrows ; movement
abruptly jerking; length 1-1260 to 1-1000".

Found in infusion of hay, and river-water,
which have been kept.

Dujardin remarks that it differs from
Enchelys nodulosa, Duj. (Pantotricum En-
chelys, Ehr.), only in the presence of the
retractile cilia.

BIBL. Dujardin, In/us, p. 391.

ALYS'SUM, Linn.— A genus of Cruci-
feree (Flowering Plants), possessing elegant
stellate hairs. See HAIBS of plants.

AM^EEJE'CIUM, or AMAKOU'CIUM,
M.-Edw. — A genus of Mollusca, of the order
Tunicata, and family Botryllidaa.

Four British species — -proliferum (PI. 18.
fig. 10), Nordmanni, Argus, and albicans.

BIBL. M. -Edwards, Mem. s. les Ascid.
Comp. ; Forbes and Hanlev, Brit. Mollusca,
i. 15 ; Gosse, Mar. Zool. ii. 33.

AMA'THIA, Larnx. See SERIALABIA.

AMBER. — This substance, found as a
mineral, but strongly resembling in appear-
ance various gum-resins, is the fossil resin of
one or more Coniferous trees belonging to a
vegetation now extinct. It is found in drops,
lamellae, and stick-shaped pieces, the form
and condition depending probably on the
mode and situation of its exudation from the
trees. In many instances the fragments of
amber contain well-preserved remains of the
animals and plants which lived at the period
of its formation, these having been enclosed
by the fluid resin as it escaped from the tree,
in a manner which may be exactly compared
with our mode of preserving microscopic
objects in Canada balsam. Numerous insects,
Arachnida, and other animals, with leaves,
twigs, fruits, even flowers of plants, have
been described and referred satisfactorily to
their systematic position; and the aid of the
microscope has been largely called in for this
purpose, since the elementary structures are
in many cases perfectly preserved. The
tissue of fragments of Coniferous wood, the
stomata of leaves, and glandular and other
hairs have been recognized ; and besides the
larger Cryptogams, Mosses, Jungermannise,
&c., peculiar microscopic Fungi and Diato-
niacese have been preserved in a perfectly
distinct condition.

Some of the pieces are cloudy or opaque,

from the presence of numerous minute
cavities, varying in diameter from 1-1000" to
1-100,000" "(Sorby). Some of these con-
tain gas, some liquid, and others both.

The structure of the wood of the Amber-
fir, Pinites succinifer, Gb'pp., approaches
closely that of our Pinus Abies a,ud. P. Picea,
differing scarcely in any respect but in the
smaller number of the bordered pores,
which are of slightly different form.

Two microscopic Fungi preserved in am-
ber have been described and figured by
Berkeley : Penicillium curtipes, &u<lllrachy-
cladium Thomasinum, a form approaching
Corethropis of Corda. A third form, de-
scribed at the same time as Streptothrix spi-
ralis, he now considers to be an appearance
produced by enclosed bubbles of air.

Ehrenberg detected Diatomacese in am-
ber, namely, Amphora gracilis, Cocconeu
borealis, Cocconema Cistula, Fragilaria capu-
cina, Navicula affinis, N. Amphioxys, N. Ba-
cillum, Pinnularia capitata, and P. Gastrum.
BIBL. Goppert and Berendt, Regensburg
Flora, vol. xxviii. p. 545, 1845 ; Ehrenberg,
Ber. Berl.Ak. 1848, p. 17; Berkeley, Moulds
in Amber, Ann. N. Hist. 2nd ser. vol. ii.
p. 380, tab. xi., xii. ; Idem, Crypt. Bot.
p. 303; Sorby and Butler, Mn. Mic. Jn.
xvi. p. 225, 1876.

AMBLY'ODON ,Pal. de Beauv.— A genus
of Funariaceaa (Acrocarpous Mosses). The
only species, A. (Bryum) dealbatum, is rare
in Britain.

BIBL. Miiller, Syn. Muse. i. p. 127; Wil-
son, Bryol. Brit. p. 267.

AMBLYOM'MA, Koch.— A genus of
Acarina (Arachnida), fam. Ixodea.

Infests cattle, &c. South America, and
Sandwich Islands.

BIBL. Koch, Arachnid.: Murray, EC.
Ent. p. 201 (fig.).

AMBLY'OPHIS, Ehr.— A genus of In-
fusoria, of the family Astasiaea.

Char. Unattached; a single (red) eye-
speck; a simple flagelliform filament, no
tail. One species.

A. viridis (PL 30. fig. 55). Green ; length
1-210 to 1-140".

Anterior end of the body colourless, and
cleft so as to represent a two-lipped mouth ;
nucleus near the middle of the body.

Several authors regard this as a Euylena.
BIBL. Ehr. Infus. p. 103; Dui. Infus.
p. 636; Kent, Inf. p. 385.

AMBLYSTE'GIUM, Br. and Sch.— A
genus of Mosses included under HYPNUM by
Miiller and Wilson.

AMEIRA. [ c

AMEI'R A, Boeck.— A genus of Copepoda
(Entoinostraca).

A. longipes. Marine. North Britain.

BIBL.' Boeck, Overs. Norges Copepoder ,
1864, 49 j Brady, Copepoda (Hay Soc.), ii.
36.

AMI'BA, Duj. See AMCEBA.

AMMONIA, HYDROCHLORATE OR MU-
RIATE OF. — This salt crystallizes in cubes,
octahedra, and trapezohedra. When crys-
tallized rapidly it forms curious feathery
aggregations (PI. 11. fig. 9). The crystals
do not polarize light.

AMMONIA, OXALATE OF. — This salt is
readily prepared by neutralizing a solution
of oxalic acid with ammonia or its carbo-
nate, and evaporating.

It crystallizes in long slender needles,
belonging to the right rhombic prismatic
system. When mounted in Canada balsam,
these form a very beautiful object for the
polariscoipe (PI. 39. fig. 7).

AMMONIA, OXALURATE OF; formerly
known as the lithoxanthate of ammonia.

This salt may be prepared by mixing

1 part of uric acid with 32 parts of water,
and heating the mixture in a porcelain cap-
sule until it acquires a boiling temperature.
Strong nitric acid, previously diluted with

2 parts of water, is next added in small
quantities at a time, until nearly the whole
of the uric acid is dissolved. The liquid is
then boiled, filtered, mixed with excess of
solution of ammonia, and concentrated by
evaporation. As it cools, the salt is depo-
sited in needles or warty groups of crystals.
These are freed from the mother-liquor by
pressure between blotting-paper, dissolved
in warm water, and a little solution of am-
monia added. On evaporation the pure salt
separates.

The oxalurate of ammonia forms one of
the most beautiful and interesting sub-
stances that can be examined by the polar-
izing microscope. When a small quantity
of its aqueous solution is slowly evaporated
on a slide, some of it usually crystallizes in
circular crystalloid disks or very flat spheres,
consisting of minute needles radiating from
a centre and in an intimate state of mecha-
nical adhesion ; sometimes the extremities
of the needles are seen projecting beyond
the circumference of the disks. The latter
appear colourless or yellowish by reflected
light ; pale or dark brown or even black by
transmitted light, according to their size and
thickness. When immersed in Canada bal-
sam, they become transparent, often nothing

| AMMONIA.

more being distinguishable than radiating
lines, indicating the needles of which they
are composed. But if examined by polar-
ized lignt and with the analyzer, when
these are so arranged that the plane of po-
larization of the analyzer is at right angles
to that of the polarizer (the field being
black), the disks present the appearance of
beautiful little stars, sometimes almost
white, at others splendidly coloured, each
being also traversed by a black rectangular
cross (PI. 39. fig. 11).

On rotating the slide, no change is pro-
duced. But on rotating the analyzer or
polarizer 90°, the arms of the cross appear
to rotate, which, as there are no fixed points
visible in the disks, gives rise to the ap-
pearance of the disks themselves rotating.
When the analyzer has Been rotated a quar-
ter of a revolution, the former position of the
black cross is occupied by a white one, and
the colours of the intermediate parts become
complementary to (forming white light
with) those which they at first possessed,
these appearances being alternately repro-
duced at each quarter revolution.

If a plate of selenite is placed beneath
the slide, the beauty of the objects is much
augmented (PI. 39. fig. 12). On some parts
of the slide, dendritic aggregations of the
needles are seen (PI. 39. iig. 11 a).

Sometimes the colours are disposed in
concentric rings ; when these are well de-
fined, a concentric arrangement of the
groups of needles is distinguishable on
examining the disks by common light.

A simple experiment will show the origin
of the cross and the colours. If eight crys-
tals of any doubly refracting salt be ar-
ranged upon a slide in the directions of
equidistant radii of a circle, they may be
regarded as forming two crosses, alternating
in position. If the slide be placed under
the microscope, with the plane of polariza-
tion of the polarizer and analyzer at right
angles, and the crystals be simultaneously
rotated and kept in the same relative posi-
tion, a point will be reached at which each
alternate crystal will become black, the in-
termediate ones appearing coloured ; and on
continuing the rotation, the crystals which
were at first black will appear coloured,
those which were coloured appearing
black.

The blackness of the crystals arises from
the plane of primitive polarization of the
light transmitted by the polarizer being
parallel with the optic or neutral axis of the

AMMONIA.

AMCEBA.

crystals, consequently there is no double
refraction and no interference to produce
colour ; whilst in the coloured crystals, the
optic axis of which does not coincide with
the plane of polarization, double refraction
and interference ensue, by which the colours
are produced. The tint of colour varies
according to the thickness of the disks.

See CIRCULAR CRYSTALS and POLARIZA-
TION.

AMMONIA, PURPURATE OF, or Murex-
ide. — Is an artificial product of the decom-
position of uric acid. It may be prepared
by dissolving uric acid in dilute nitric acid,
as directed under AMMONIA, OXALURATE
OF. The solution is evaporated until it
acquires a tile-red colour ; then cooled to
exactly 158° Fahr., and dilute solution of
ammonia added to it until it is neutralized.
Half its bidk of water is then added, and
the mixture deposits the salt in crystals as
it cools.

The crystals form short, flattened, four-
sided prisms (PI. 11. fig. 10) ; they are
ruby-red by transmitted light, and the two
broad surfaces are emerald-green by re-
flected light. They are also analytic.

BIBL. See CHEMISTRY.

AMMONIA, ITRATE OF. See URATES.

AMMONIO-CHLORIDE OF PLATINUM.
See PLATINUM.

AMCE'BA, Ehr. — A genus of Rhizopoda,
of the order Lobosa, and family Amcebaea.

Char. The same as that of the family j
but the psetidopodia of one kind only.

These curious organisms constitute the
simplest forms of animal beings ; for they
consist of a single kind of matter, a simple
mass of sarcode. When first placed upon a
slide, they represent minute rounded semi-
transparent masses ; but soon, one or more
rounded or pointed lobes, or transparent
expansions, are seen to shoot out from the
margin. These move almost imperceptibly
along the slide, and, becoming fixed to it,
slowly draw the mass towards the fixed
point. They are usually found to contain
within them Infusoria," Diatomacese, Des-
midiace?e or other minute Algae which are
supposed to serve as food ; these bodies
being involved in the same manner as occurs
in the case of ACTINOPHRYS, a temporary
digestive cavity being thus formed. Some-
times vacuoles or contractile vesicles are
seen within them, containing simply the
surrounding liquid; these contract occa-
sionally and disappear.

Ehrenberg admitted four species ; to these

Dujardin added ten, and others have since
been added ; but the characters cannot be
depended upon.

They are found in almost all infusions
which have not become putrid ; also in the
slimy debris covering bodies immersed in
fresh or salt water ; sometimes on moss or
earth.

Their size varies from 1-70 to 1-2800".

Amoeba diffluem is represented in the ex-
panded state by PI. 30. fig. 9 a ; and when
contracted, by fig. 9 b ; fresh wrater.

A. princeps. Yellowish white, filled with
highly refractive granules ; 1-50" in diam.
In pools.

A. blatta, found in the common cock-
roach, has the body striated (probably the
early stage ofaGregarina).

Amoeba villosa (Wallich) has one part of
the body covered with short processes or
villi.

In many Amcebte, when the pseudopodia
are expanded, the margin of the body ap-
pears very transparent, while the inner por-
tions remain granular ; this has been re-
garded as indicating the existence of an
endosarc and an exosarc. But when a drop
of liq. potassfs is added to an Amoeba, all is
dissolved, except the granular matter of the
body, which consists of foreign particles,
oil-granules, &c.

Many so-called Amoeba are probably
early stages of Fungi, &c. ; but in such
simple structureless bodies, nothing can be
stated certainly, without the use of chemical
tests.

Certain Amoeba-forms, in which no nu-
cleus or vacuoles occur, have been separated
by Ha'ckel as MONERA ; but since any de-
tached fragment of an Amoeba, or even of
any Rhizopod, will live and form a new
being, it is evident that such characters are
valueless.

Amoeba-like movements of the sarcode or
protoplasm are often perceptible in isolated
normal and pathological structures — as in
the blood-corpuscles, the liver-cells, the
corpuscles of dropsical liquids, the embry-
onal cells of ova, &c. ; also in various vege-
table cells, the root-cells of Chara, Volvox,
the spores of Algae, the Myxogastres, &c,
Amoeba-like movements may even occur in
dead cells (Lieberkiihn).

An Amoeba with a large cilium and a
villous tail has been described by Carter ;
and a free swimming Amoeba with a cilium
by Tatem.

BIBL. Ehr. Infus. 126; Dujardin, Inf.

AMCEB^EA.

AMPHIMONAS.

231; Auerbacli, Sieb. and Kb'll. Zeitsch.
vii. 365 ; Schultze, Polythal ; Carter, Ann.
N. Hist. 1856 and 1804; Wallich, ibid.
1863, p. 198 ; Bronn, Thier- Reich, 1880 ;
Perty, Z. Kenntn. p. 188 ; Tatem, Mn. Mic.
Jn. i. p. 352 ; Lieberkiihn, Ann. N. Hist.
1870, vi. p. 497; Greeff, Arch.f. mik. An.
ii., & x. 1873, p. 51.

AMCEB^E'A, Ehr.— A family of Rhizo-
poda, of the order Lobosa.

Char. Animals shell-less, composed of a
glutinous substance, without integument or
internal structure, constantly changing form
by the protrusion and retraction of parts of
the body, whence result variable expansions ;
movement slow.

They are propagated by spontaneous fis-
sion. When cut or torn, each segment
contracts upon itself and forms a new being.
Spermatozoa have been stated to be formed
from the nucleus, and ova formed from the
sarcode, by Carter in Amoeba ; Greeff also de-
scribes spermatozoa, but these are doubtful.

Gen. : Amoeba. Pseudopodia of one kind.

Podostoma. Pseudopodia of two kinds, —
one large and for locomotion, the other-
forming a proboscis, and serving for nutri-
tion.

Petalopm. Pseudopodia cylindrical, ex-
panding at the ends into thin plates.

AMPELOM'YCES, Ces. See OIDIUM.

AMPHIBLESTKA, Presl.— A genus of
Polypodiaceous Ferns; now referred to
Dictyozyphium and Pteris. — Exotic.

AMPHICAM'PA, Ehr.— A doubtful ge-
nus of Fossil Diatomaceae.

A. Eruca (PI. 18. fig. 11).

A. mirabUis (PI. 18. fig. 12).

Fossil at Tisar, Mexico.

BIBL. Ehrenberg, Be>\ d, Berl Ak. 1855,
86 ; and Mikrog.

AMPHIDIN'IUM, Cl. and L.— A genus
of cilio-flagellate Infusoria.

A. operculatum (PI. 53. fig. 2). Marine,
Norway.

BIBL. Cl. and Lachm. Infus. p. 410 ; Kent,
Inf. p. 461.

AMPHID'IUM, Nees.— A genus of
Mosses, included under ZYGODON.

AMPHILEP'TUS.— A genus of Infusoria,
of the family Colpodea (Ehr.).

Eye-spot wanting; no tongue-like pro-
cess ; proboscis and tail present.

The so-called proboscis resembles in ap-
pearance a neck. The mouth is situated
beneath the junction of the proboscis and
the body.

Dujardin gives the following characters,

placing the genus among his Paramecina.
Body elongated, fusiform or lanceolate, nar-
rowed at each end, or at least at the anterior
extremity, and furnished with an oblique
lateral mouth.

These animals are usually found in clear
marsh water, and in streams, between
aquatic plants. They are all furnished with
cilia but one ; in some these are arranged in
longitudinal rows. Species : —

Amphileptus anser, E. (Dileptus amer,
D.). Colourless ; length 1-120". Proboscis
obtuse, as long as the body.

A. margaritifer, E. and D. Colourless ;
1-72". Proboscis acute, as long as the
body.

A. moniliger, E. and D. Colourless;
proboscis short ; nucleus moniliform ; 1-72
to 1-96".

A. viridis, E. and D. Green ; 1-120 to
1-46".

A. fasciola, E. and D. Colourless ; linear-
lanceolate ; 1-720 to 1-144" (PI. 30. f. 10 a,
from above ; b, side view).

A. mekagris (Loxophy Hum mekagris, D.).
Colourless ; 1-72" (PL 31. f. 42 a; b, anterior
portion in side view).

A. longicottis, E. Colourless; rounded
behind, tapering in front; 1-120 to 1-98".

A. papillosus, E. Yellowish brown; body
covered with papillae ; 1-600 to 1-430".

A. vorax, D. (Trachelius vorax, E.).
Colourless.

A. ovum, D. (Trachelius ovum, E.).
Colourless.

Claparede and Lachmann describe other
species.

See TRACHELINA.

BIBL. Ehr. Infusionsth. p. 354 ; Dujardin,
Infus. p. : 483; Claparede and Lachmann,
Infus. p. 349; Kent, Infus. p. 523.

AMPHILG'MA (Fr.), Nyl.— A genus of
Lichens, fam. Lichenacei.

Char. Thallus white, pulverulent, soft,
submembranaceous, containing granula
gonima. Hypothallus bluish-black, tomen-
tose.

A. lanuginosum. On shady mossy rocks,
frequent.

BIBL. Leighton, Lich.-Flora, 1879, p. 156.

AMPHIM'ONAS.— A genus of Infusoria,
of the family Monadina (Duj.).

Found in kept saline solutions and marsh
water. Species : —

A. dispar. Colourless ; length 1-3860 to
1-2700" (PI. 30. fig. 11).

A. caudata (Bodo saltans ?, Ehr.). Co-
lourless ; 1-2180 to 1-1270".

AMPHIMORPIIIXA.

AMPHISTEGIiNA.

A. brachiata. Colourless.

BIBL. Dujardin, In/us, p. 292.

AMPHIMORPHPNA, Neugeboren.—
One of the dimorphous Nodosarine Forami-
nifera, in which the older portion has grown
on the Frondicularian plan, and the younger
chambers are Nodosarian or Dentaline.
Tertiary, Germany.

BIBL. Verhand. Siebenbiira.'lSSO.

AMPHIPEN'TAS, Ehr.— A doubtful
genus of fossil Diatomaceae (Cohort Anguli-
ferae).

Char. Unattached; frustules cubical,
solitary, bivalve, and pentagonal.

A. Pentacrinus ; diam. 1-240" ; Greek
marl.

A. alternant (PI. 25. fig. 11) ; Cuba.

BIBL. Ehrenb. Ber. d. JBerl. Ak. 1840
and 1843, Abhl 1841 ; Kiitziug,-5ac. p. 136 j
Babenhorst, Alg. i. p. 319.

AMPHIPLEU'RA, Kiitz.— A genus of
Diatomaceae (Cohort Amphiple ureas).

Char. Frustules free, straight or slightly
sigmoid ; valves lanceolate or linear-lanceo-
late, with a median longitudinal line which
is thickened and expanded longitudinally at
each end, but without a median nodule.

The valves appear to resemble those of
Nitzschia in their inequality ; but they are
compressed in the opposite direction to those
of that genus, and thus the median lines of
both valves are visible at once. That the
lines seen upon the frustules are the same as
the median lines of the separated valves, is
evident from their exhibiting the terminal
expansions. This view is confirmed by the
sides of the frustules being half as broad
again as the separate valves.

A. pellucida (PI. 16. fig. 7a, side view of
frustule ; 6, of valve). Valves linear-lanceo-
late ; length 1-225" ; furnished with longi-
tudinal and transverse striae, of extreme
delicacy, requiring the best object-glasses of
large aperture, and the most oblique light,
to render them visible. Sollitt estimates
them at 125 to 130 in 1-1000". Nelson at
80 to 1-1000" longitudinal, and 96tranverse,
(bv vertical illumination) : Jn. Mic. Soc. i.
p. "152, 1881). Fresh water : Brit.

A. rigida, K. (sigmoidea, Sm.). Marine ;
valves narrowly linear-lanceolate, slightly
sigmoid ; length 1-150" (PI. 16. fig. 7 c, side
view) ; British.

A. Danica, K. Valves lanceolate, trun-
cate ; length 1-400" ; coast of Denmark.

A. inflexa. Marine ; linear, lunate, slightly
attenuate at ends, obtuse; length 1-330";
British.

A. Lindheimeri. Larger than A. pell.
in fr.-wat. torrents, N. Amer. (Grun, Oestr.
Diat. i. p. 469, fig.).

A. Frauenfeldii. Indian Ocean. Grun,
ut supra.

BIBL. Kiitzing, Badll. p. 103 ; Sp. Alg.
p. 88 ; Smith, Brit. Diat. i. p. 45 ; Raben-
horst, Flor. Alg. i. p. 143.

AMPHIPRO'RA, Ehr.— A genus of Dia-
tomaceae (Cohort Naviculeae).

Char. Frustules free, soli tary, constricted
in the middle ; valves convex, having a me-
dian keel, with a nodule at each end, and
either a nodule or stauros in the middle.

Marine, or inhabitants of brackish water.

Frustules sometimes much twisted, oc-
casionally resembling a violin in form, from
one half of the frustule being in a longitu-
dinal plane almost at right angles to that of
the other. Surface of the valves more or
less distinctly marked with transverse striae,
which under high powers and proper mani-
pulation are resolvable into dots, arranged
as in PL 15. fig. 8. Many species.

A. alata; E. Common (PI. 16. fig. 8 a
side view ; b, front view). Fr. twisted
fr. view linear, ends rounded ; valves nar-
rowly elliptical.

A. constricta, E. Fr. straight, narrow ;
valves with a transverse line,, ends acute.

Rabenhorst separates the species with a
distinctly curved, mostly sigmoid keel, in a
genus Amphicampa.

BIBL. Ehr. Abh. Berl. Ak. 1841, p. 333 ;
Kiitzing, Badll p. 107 ; Sp. Alg. p. 93 ;
Smith, Brit. Diat. i. p. 43, ii. p. 92; Greville,
Mic. Tr. 1863, pp. 13, 20 ; 1865, p. 105 ;
Ann. N. Hist. 1865, xvi. p. 5 ; Gregory,
Diat. of Clyde, p. 33 ; Grun, Verh. Wien,
1860, p. 569 ; Donkin, Qu. Mic. Jn. 1861,
p. 14 ; Rabenhorst, Flora Alg. i. p. 253.

AMPHISTA, Kent.— A genus of Infu-
soria, fam. Oxytrichina.

BIBL. Kent, Inf. 1880.

AMPHISO'RUS.— The compound or
aged individuals of Orbitolites orbiculus,
having chambers on both faces of the disk,
are grouped by Ehrenberg under this genus
of his Bryozoa polysomatia.

BIBL. Ehrenberg, Abh. Berl. Ak. 1838;
Carpenter's For. p. 105.

AMPHISTEGI'NA, D'Orb.— One of the
high-class genera otForaminiferaperfo?*afa,
of the Nummuliue family. It differs from
Nummulina mainly in not being symmetri-
cal, one face being more conical than the
other. On the flatter face the alar flaps of the
chambers are as in Nummulina ; but on the

AMPIIISTOMA.

AMYLOBACTER.

other they are packed in around the umbo
among the chambers, to which they are at-
tached by very narrow necks. The aperture
also lies somewhat on this side of the me-
dian plane. Living abundantly in some
parts of the tropical seas ; and found fossil
in some Tertiary strata younger than those
rich in Nummulites. Recent, South Seas ;
fossil, Middle Tertiary, Australia, Europe.

Amphistegina Haueri (PI. 24. fig. 38).

BIBL. D'Orbigny, For. Foss. Vien. ; Car-
penter, Foram. p. 241.

AMPHIS'TOMA (Holostomum, Diplo-
discus). — A genus of Entozoa of the family
Trematoda.

Char. Body soft, oval, cylindrical or co-
nical ; intestine 2-branched ; two pores, one
anterior, the other posterior forming a large
sucker.

The species are numerous, most common
in birds, but sometimes occur in mammalia,
reptiles, and fishes ; generally inhabiting the
alimentary canal ; length from 1-10 to 4-5
of an inch.

A. hominis, in man (India) ; near the ileo-
colic valve; red; £" long.

BIBL. Dujardin, Helm. p. 327; Diesing,
Syst. Helm. ; Proc. Asiat. Soc. 1876 j Cob-
bold, Paras. 1879, p. 37 (fig.)-

AMPHITET'RAS, Ehr.— A genus of
Diatomacese (Cohort Anguliferae).

Char. Side view of the f rustules rectangu-
lar, the angles sometimes produced ; valves
covered with depressions, which are readily
seen under a low power.

This genus approaches Isthmia and Bid-
dulphia, from which it differs in its rectan-
gular and not compressed figure.

A. antediluviana (PI. 16. fig. 9) ; o, frus-
tules united ; b, side view ; c, front view ;
d, perspective view. Lateral surfaces of
the frustules with concentric radiating de-
pressions, their sides concave. British ;
marine.

A. adriatica. Depressions concentric
and radiating ; angles of the frustules ob-
tuse ; lateral surfaces of frustules with
straight sides ; Adriatic sea.

A. parallela. Depressions parallel; in
Greek marl.

10 other species.

BIBL. Kutzing, Badll. p. 135 j Sp. Alg.
p. 133 ; Ehrenberg, Abh. d. Berl. Ak. 1839,
pp.122, 144; Greville, Mic. Trans. 1865,
p. 105, 1866, p. 9 ; Rabenhorst, Flor. Alg.
i. p. 318.

AM'PHITHRIX, Ktz.— A genus of Ri-
vulariaceous Algae j consisting of erect,

tufted, flagelliform filaments ; with crowded
fine articulated fibrils at the base. On wet
rocks, the sides of aquaria, &c. ; fr. water.

A. papillosa (PI. 3. fig. 4).

BIBL. Rabenhorst, Alg. ii. p. 229.

AMPHIZONEL'LA, Greeff.— A genus of
Rhizopoda=-/4w«&a with a very delicate
shell.

3 species ; fresh water.

BIBL. Greeff; Arch. f. mik. An. 1866, ii.
p. 323 ; Bronn, Klaus, pi. 1. fig. 7.

AM'PIIORA, Ehr.— A genus of Diato-
macese (Cohort Naviculese).

Char. Frustules solitary, free or adherent;
valves with a nodule or a stauros at the
middle of the margin on the inner side.

The nodules exist on the flat side of the
frustules ; the frustules are plano-convex ;
PI. 16. fig. 10 a represents a transverse sec-
tion ; the side view of the frustules can only
be seen when these are made to roll over
by sliding the glass cover upon the slide
with the mounted needle. (INTRODUCTION,
p. xxiii.)

The valves are furnished with transverse
striae, resolvable into dots, but in some spe-
cies these are excessively minute.

The species are both marine and aquatic.

A. ovalis, K. Aquatic ; frustules turgid,
oval, ends rounded or truncate ; length
1-400"; common. (PI. 16. fig. 10, front
view; 10 a represents a transverse section.)

A. minutissima, S. Aquatic, adherent to
other Diatomacese ; valves with a stauros ;
length 1-1200".

A. costata, S. Marine ; ends beaked j
valves longitudinally ribbed ; length 1-500".

A. membranacea, S. (PI. 16. fig. 11);
brackish water.

Rabenhorst describes 54 European and
22 other species.

BIBL. Kiitz. Bacill. p. 107 ; Sp. Alg. p.
93; Smith, Brit. Diat. i. p. 19 ; Rabenhorst,
Flor. Alg. i. p. 86.

AMPHOROPH'ORA, Buckt.— A genus
of Aphidse.

A. ampullata is very large, green ; eyes
red, with very long antennae fixed on the
frontal tubercles ; cornicles large, dilated in
the middle, with black trumpet-shaped
orifices. On Cystopteris montana.

BIBL. Buckton, Aphides (Ray Soc.}.
1879, i. p. 187.

AMYLOBAC'TER, Tre*cul.— The orga-
nisms to which this name has been applied
are obtained by macerating the stems of
plants of various families in water. They
are round, or oval, often bacillar and capi-

AMYLOID.

[ 39 ] ANALYTIC CRYSTALS.

tate ; about 1-50,000" in length (PI. 53.
fig. 5). They are formed within the latici-
ferous vessels, but also within cells or fibres,
and between the cells. They are coloured
yellow by iodine, sometimes purple by sul-
phuric acid. They seem to correspond to
amylaceous Bacteria. They sometimes ex-
hibit rapid movements. Their formation
within closed spaces has raised the question
of spontaneous generation.

BIBL. Trecul, Compt. rend. 1865-7-8;
Nylander, Flora, xxxviii. 522, 1865 ; Robin,
-flftcr.881; v.Tieghem, Butt.S. bot. Fr.xxiv.

AM'YLOID. — This name was given by
Schleiden and Vogel to a peculiar modifica-
tion of vegetable substance met with in the
thickening layers of the cell-walls, in the
cotyledons of certain Leguminosae, viz.
Schotia speciosa, S. latifolia, Hymencea
Courbaril, Mucima wens, M. gigantea, and
the tamarind (Tamarindus indicd) ; also of
the common white Haricot bean. When
in a dry condition, it is of a soft horny con-
sistence ; when wetted, it softens, becomes
gelatinous and transparent ; it is soluble in
boiling water, strong acids, and in solution
of potash, but not in alcohol or ether. It is
coloured blue by iodine, like starch, the
compound being soluble in water with
change to a yellow colour. The ' amorphous
starch/ described by Schleiden, in the seeds
of Cardamomum minus, in the rhizomes of
Carex arenaria and Sarsaparilla, seems
scarcely distinct from amyloid ; it forms a
thick viscous layer lining the cells. Amyloid
forms a transitional substance between
starch and bassorin and cellulose, and pro-
bably presents modifications approaching
more nearly to one or other of them in dif-
ferent plants.

"When cellulose .is treated with a mixture
of 4 parts of sulphuric acid and 1 of water,
it swells into a clear jelly, which is at first
stiff, but gradually acquires liquidity ; alco-
hol or water throws down from it white
flakes of amyloid, which are coloured blue
like starch by^ iodine. It differs, however,
from starch in the circumstance that the
iodine can be washed out of it, and the blue
colour made to disappear by the action of
water, which is not the case with starch.

The so-called Amyloid substance of Vir-
chow consists of a nitrogenous matter,
closely allied to albumen. It is coloured
deep reddish-brown by iodine, the addition
of sulphuric acid sometimes producing a
bluish-black or violet tint. It occurs in tis-
sues and organs affected with the waxy or

lardaceous degeneration, as the small arte-
ries, the liver, the kidneys, the spleen, and
the lymphatic glands.

See CELLULOSE and STARCH.

AM'YLCJM. See STARCH.

AMYMO'NE, Glaus.— A genus of Cope-
poda (Entomostraca).

A. sphcerica and longimana. In dredg-
ings.

BIBL. Brady, Copepoda {Ray Soc.}, ii. 28.

ANABAI'NA, Bory. See TRICHORMUS.

ANACALYP'TA, Kohl.— A genus of
Mosses, made a section of POTTIA by Miiller.

BIBL. Miiller, Syn. Muscor. i. p. 547;
Wilson, Bryol. Brit. p. 97.

ANACH'ARIS, Rich.— A genus of Hy-
drocharidaceae (aquatic Monocotyledon ous
Plants). A. Alsinastrum, Bab., which is
apparently identical with Udora canadensis,
a North- American plant, has become widely
diffused in Britain during the last few years
in ponds and streams. It is of great interest
to microscopic observers, on account of the
facility with which the . ROTATION of the
cell-contents may be observed in its living
tissues. It is commonly cultivated in jars
of water for this purpose.

BIBL. Wenham, Qu. Mic. Jn. iii. p. 277.

ANAL'GES, Nitzsch.— Agenus of plumi-
colous Acarina, fam. Sarcoptidae. In the
species, the integument is striated ; the 3rd
pair of legs very large and long ; the abdo-
men entire.

Five species ; on birds.

BIBL. Megnin, Parasites, 1880, p. 149,

ANACYS'TIS, Meneg.— A genus of
Palrnellaceous Algae ; consisting of very
numerous spherical green cells, imbedded in
mucus, and enclosed in a lamellar envelope.

A. marginata (PI. 52. fig. 8*). Found
floating in fr. wat. pools, or on other algae.

A. Grevillei, on dead stalks of asparagus.
Other species.

BIBL. Kiitz. Tab. Phycol.\. pi. 9. figs. 2-4;
% Alg. p. 209 j Berkeley, Gleanings $c. ;
H&ssa\\ Brit. Alg. ( C0cco<?/W0m);Rabenhorst.
Fl. Alg. ii. p. 52.

ANALYTIC CRYSTALS.— A term
proposed by Fox Talbot, in 1837, to desig-
nate those crystals which possess the powrer
of analyzing polarized light, like the tour-
maline. The substances in which this pro-
perty is best exhibited are the nitrate of
potash, the sulphate of chrome and potash
dissolved in tartaric acid by heat, boracic
acid, the oxalate of chromium and potash,
allantoin, hippuric acid, urea, oxalate of urea,

ANALYTIC CRYSTALS.

40 ]

ANAULUS.

uric acid, &c. They must be immersed in
Canada balsam. The crystalline compound
of disulphate of quinine with iodine is infe-
rior to none in this power. The phenomena
scarcely need description, since analytic crys-
tals merely play the part of a thick plate of
tourmaline, or a Nicol's prism : i. e. if polar-
ized light be transmitted through them (a
polarizer alone being used), in one position
they suffer it to pass freely, while if they are
rotated 90° they arrest or absorb it entirely,
or to a greater or less extent : and if a plate
of selenite, or other depolarizer, be placed
beneath the slide upon which the crystals
are situated (without the analyzer) the lat-
eral surfaces are seen to be coloured, the
complementary tints appearing at each
quarter rotation.

Of course these crystals will act equally as
polarizers and analyzers. Fox Talbot gives
the following explanation of the cause of the
phenomena in the crystals which he exa-
mined. When a beam of polarized light is
transmitted very obliquely through a small
prism of nitre, its outline generally exhibits
two colours instead of one ; for while the
edge of the prism, which is on that side
from which the ray of light comes, is, for
instance, red, the opposite edge will appear
green. On reversing the polarization of the
light, these colours are exchanged. This ob-
servation shows why the phenomenon only
occurs in crystals possessing strong double
refraction, like nitre, in which the refractive
indices of the two rays are materially dif-
ferent. When a ray of common light is in-
cident upon such a crystal, and therefore is
divided into two rays oppositely polarized,
both rays are transmitted through the cen-
tral parts of the crystal, which are bounded
by parallel planes, or by planes approaching
to parallelism. But when the bounding planes
of the crystal are much inclined to each other,
and therefore refract the light in the manner
of a prism, the refractive indices of the rays
may differ so much, that while one passes free-
ly through such a prism, the other cannot pass
at all, but suffers total internal reflection,
and is thereby dispersed; just as if the prism
had a larger reflecting angle with respect
to that ray than to the other. Therefore if
two oppositely polarized rays are presen-
ted to such a crystal as in our experiment,
one will be transmitted and the other not.
That this is the true explanation appears
from this, that when the oblique planes are
well-formed and clearly defined by the mi-
croscope, the colour also is accurately limited

by the same boundary ; so that while this
part analyzes the tints of a plate of sulphate
of lime, the rest of the crystal is inactive.

That internal reflection and dispersion,
however, are not the cause of the separation
of the coloured rays, is shown by the fact
that those lateral surfaces of crystals which,
when viewed through the microscope (with
the polarizer and plate of selenite alone), ap-
pear of a certain colour, say green, exhibit
the complementary tint, red, when viewed
with the naked eye from the side of the
stage; hence the two coloured rays are se-
parated merely by refraction.

The margins of cavities containing air and
air-bubbles, which sometimes exist in the
crystals, exhibit the colours in the same
manner and from the same cause as the
lateral oblique surfaces of the crystals.

Nothing can surpass the curious and beau-
tiful appearance presented by analytic crys-
tals, tne delicacy and brilliant transparency
of their coloured margins giving them the
aspect of figures drawn with coloured ink.

PL 11. fig. 11 a, 6, represent two crystals of
nitre, viewed with the polarizer but without
the analyzer or the plate of seleiiite; fig. 12
a, b, represent two crystals as seen when the
polarizer and plate of selenite are used, exhi-
biting the complementary colours; fig. 12 c
represents an air-bubble enclosed in the crys-
tal. See DICHBOISM and POLARIZATION.

BIBL. Brewster, Phil. Trans. 1835 ; Fox
Talbot, ibid. 1837.

ANARTHROP'ORA, Smitt,= Lepralia
part.

A. monodon= Lepr. mon.; on stones from
deep-sea water.

BIBL. Hincks, Polyzoa, p. 232.

ANAU'LUS, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, compressed, sub-
quadrate, not furnished with either tubular
processes, nodules or apertures, but having
lateral constrictions.

In the latter character it resembles Bid-
dulphia.

Kiitzing admits one species : —

A. scalaris, Ehr. (PI. 18. fig. 7). Valves
turgid in the young state, very broad and
flat when mature ; having 4, 6, 8, or 14
lateral constrictions, which give the front
view a ladder-like appearance; marine; dia-
meter 1-470 to 175". Antarctic Ocean.

A. indicus, ~Ekr.= Terpsinoe indica, Kiitz.

BIBL. Ehrenberg, Ber. d. Berl. Ak. 1844,
p. 197 ; 1845, p. 361 ; Kiitzing, Sp. Ala pp
119, 120.

ANBURY.

I 41 ]

ANEMIA.

AN'BURY, or Ainbury, popularly club-
root or fingers-and-toes, is a disease peculiar
to the Brassicaceae. It consists in the for-
mation of galls or warts, often of large size,
on the lower part of the steins and the
roots. It has been attributed to various
causes : in some instances, the larvae of a
weevil have been found within the galls, to
which their origin might fairly be attribu-
ted. The Aphidae have also been supposed
to produce these tumours ; this Buckton de-
nies. The later researches of Woronin have
traced this disease to the agency of an ally
of the Myxomycetes, called Plasmodiophora
BrassictB.

BIBL. Johnson, Gardener's Diet. p. 31;
Buckton, Aphides (Ray *Sbc.), ii. p. 20;
Woronin, Pringsheim Jahrb. xi. p. 548 (pis.).

ANCHOEEL'LA, Ouvier.— A genus of
Crustacea, of the order Siphonostoma.

Char. Body short, produced in front into
a kind of neck, which is transversely rugose ;
arms two, furnished with a sucker or adhe-
sive disk at the end, and confluent through-
out their length.

Two British species —

A. uncinata (PI. 19. fig. 7), milk-white ;
found on the gills and gill-covers of the cod,
haddock, and whiting ; length about 1-2".

A. rugosa, found on a species of cod;
length about 1-3".

The above characters refer to the female.

BIBL. Baird, Brit. Entom. p. 336.

ANCYR'IUM, Werneck. — An obscure
genus of Infusoria.

Char. That of an Enterodelous Bodo, with
a nioveable setaceous foot.

6 (?) species.

BIBL. Werneck, Ber. d. Berl. Ak. 1841,
p. 377.

ANCHYLOS'TOMA, Dubini.— A genus
of Nematoid Entozoa.

A. duodenalis=Dochmit(s duod.

A. dysenterica (PI. 53. fig. 4) is of doubt-
ful position. It is about 1-100" in length ;
curved and transparent in front, yellow and
opake behind, and expanded at the base. It
is firmly attached to the mucous membrane
in large numbers ; and occurs in the dejec-
tions of diarrhoea and dysentery in hot cli-
mates.

BIBL. Dounon, Parasites 8fc. 1877; Beau-
regard, Mic. 1880, p. 610.

ANCYRO'MOSAS, Kent. — A genus of
flagellate Infusoria, fam. Monadidae.

Char. Ovate or elongate, free or adherent ;
flagellum single, trailing at the end, vibra-
tile elsewhere ; a nucleus and vesicle present.

A. sigmoides, among decaying Fiicus,
Jersey ; length 1-5000".

BIBL. Kent, Infm. p. 247.

ANCYS'TROPUS, Kohl.— A Pteroptw,
found on Egyptian bats ; dull yellow, with
blackish markings, legs brown. Murray,
EC. Ent. p. 180 (fig.).

ANDR^E'A, Ehr.— A genus of Mosses.
See ANDR^ACE^.

ANDR^EA'CE^E.— A family of Schisto-
carpous Mosses, characterized especially by

Fig. 10.

Fig. 11.

Andraea rupestris.
Fig. 10. A sporange not yet open.
Pig. 11. A sporange burst into four valves, united at
their points. Magnified 20 diameters.

the peculiar mode of splitting of the fruit,
somewhat analogous to that which is found
in Jungermannia, the urn-shaped capsule
dividing perpendicularly when ripe into
four or eight valves, which usually remain
attached together at their points '(figs. 10
and 1 1) . But the capsules always differ from
those of Jungermannia in the presence of a
columella. The cells of the leaves are pa-
renchymatous, with their walls thickened,
and somewhat papillose on the surface. The
calyptra at first covers the capsule entirely,
then splits off as a mitre-shaped or bell-
shaped cup. The archegonia and antheridia
are either on the same or distinct plants,
and the latter terminal on distinct branches.
The few British species are natives of rocky,
usually alpine ™

districts, and
belong to the
genus Andrcea.
In Acrochis-
ma, an antarc-
tic genus, the
sporange splits
only part of
the way down.
BIBL. Wil-

SOn Bryol Group of sporanges bursting to dis-

Britann.y.ll. charge the spores- Maenified-

ANE'MIA (^wmmV^Swartz. — A genus
of Schizeeaceous Ferns (fig. 12).

Anemia mandioccana.

ANELLIDA.

ANGUILLULA.

Char. Capsules small, very abundant,
forming a copiously branched panicle.

Several species ; ^mostly from tropical
America.

The fertile fronds, bearing the sporangia,
are reduced to mere ribs.

BIBL. Hook. Sp. Filic. p. 431.

ANEL'LIDA. See ANNULATA.

ANEU'RA, Dumortier. — A genus of

Pelliege (Hepati-
cse), growing in wet
places, containing
3 British species.

A. pinguis, L.
Frond irregularly
branched, margins
sinuate, calyptra
smooth, whole
plant brownish-
green . = J. pinguis,
Hooker, Br. Jun-
germ. t. 46 (fig.
13).

A. multifda, L.
Frond bipinnately
divided, calyptra
tuberculate. = J.
multijida, Hooker,
Br. Jungerm. t.
45 (figs. 14 and
15).

Fig. 14.

Fig. 13.

Aneura pinguis.
Bursting sporanges. Magni-
fied 2 diameters.

Fig. 15.

Aneura multiflda.
Fig. 14. Portion of a frond with young perichaetes,

magnified 20 diameters.
Fig. 15. A perichaete, more magnified, cut open to

show the archegonia.

A. palmata, Nees. — Frond palmate, ca-
lyptra tuberculate, —J. multifida, var. pal-
mata, Hooker.

BIBL. Hooker, Brit. Jungermannia :
Sachs, Sot. 1874, p. 355.

ANGIOP'TERIS, Hoffmann.— A genus
of Marattiaceous Ferns. Exotic.

BIBL. Hooker, Sp. Ftt. p. 440 (pi. 9).

ANGUIL'LULA, Miiller (Rhabditis,
Duj.). — A genus of animals, formerly placed

among the Infusoria, but arranged in the
order Nematoidea of the class Entozoa by
modern zoologists. The popularly known
" eels " in vinegar and paste belong to this
genus.

Char. Body filiform, narrowed at the
ends; mouth terminal, round, naked; anus
subterminal ; tail of male either naked or
furnished with a membrane (winged); a
double spiculum; tail of female conical,
acute. Mouth succeeded by an oblong ca-
vity (pharynx) ; stomach top-shaped or
spherical, furnished with a kind of dental
armature. Tail of the female frequently
prolonged into a fine point. Uterus bifid ;
vulva situated near the posterior third of
the body. Oviparous or viviparous.

These animals are especially remarkable
and interesting on account of their great
tenacity of life ; resembling in this respect
the Tardigrada and Rotatoria. Thus Ang.
flumalilis, when existing in places exposed
to the heat of the sun, will dry up and be-
come hard and brittle. But as soon as re-
moistened by rain, it revives, swells up, be-
comes soft, takes food and exercises its re-
productive functions as before. The same
faculty is possessed to an extraordinary de-
gree by Ang. tritici, which will revive after
having been kept in a dry state for more
than five years. Nor are they destroyed by
being frozen.

Ang.fiuviatilis (?) (Ang. terrestris, Duj.)
(PI. 21. fig. 4). White, about 15 times
as long as broad ; oesophagus fusiform, ex-
panded posteriorly so as to become continu-
ous with the much larger stomach; length
of male 1-50 to 1-12".

Found in wet moss and moist earth,whence
it gets washed into rivers and ditches;
sometimes also in the intestinal canal of
snails, frogs, fishes, worms, and insects.

Ang. aceti (PL 21. fig. 5). From 30 to
45 times as long as broad, narrowed poste-
riorly and terminated by a drawn-out point ;
ossophagus cylindrical; tail conical. pointed:
length 1-30 to 1-17".

This species was formerly very common
in vinegar, and the " eels in vinegar " were
favourite popular microscopic objects. To
the freedom of our vinegar from mucilage,
and the addition of sulphuric acid allowed
by law, must be attributed their compara-
tive rarity in the present day. Still, if to
cheap vinegar, in which a few may be per-
ceived by a hand-lens, a little flour be added,
they m&y be bred in swarms.

Ang. tritici (PI. 21. fig. 6). 20 times as

ANGUILLULHLE.

ANGULAR APERTURE.

long as broad in the adult state j length
1-42 to 1-4" ; pharynx with an exsertile
spear, trilobed at the base.

Found in blighted wheat, and sometimes
infesting the young plants, burrowing in the
leaf-sheaths, where we have found them re-
producing by ova, in great numbers.

Ang. glutinis. About 20 times as long
as broad, terminating posteriorly in a fine
elongated point; length 1-15''.

Found in sour paste.

Other so-called Anguillulce are found in
the same situations as A. Jtuviatilis. See
ENOPLID.E.

Ang. (Leptoder*) stercoralis is a simple,
smooth-bodied nematode 1-625" long;
somewhat narrowed in front, and more so
behind ; the males and females being nearly
equal in size. Found in enormous num-
bers in the evacuations of patients in Cochin-
China.

Ang. (Lept?) intestinalis is a larger spe-
cies, sometimes found with the above, but
less numerous; length 1-11", breadth
1-767",

It is almost impossible to dissect these
minute beings in the ordinary manner ; the
best method of proceeding is to wound the
body, and gently press out the contents
under water.

BIBL. Duges, Ann. Sc. Nat. 182G, ix. ;
Bauer, Phil Tr. 1823 ; Ehrenberg, Symbol.
Phys.; Dujardin, Helminthes ; Davaine,
Ann. N. H. 1856, xviii. p. 268; Bavay,
ibid. 1877, xix. p. 350; Kiihn, Sieb. & Kol-
liker's Zeitsch. 1857, p. 129; Bastian, Linn.
Tr. 1865, xxv. 73; Cobbold, Entozoa, 1879,
p. 236 (figs.).

ANGUILLU'LIDJE.— A family of ne-
matoid worms.

This family corresponds pretty nearly to
the Enoplidae of Dujardin. The genera
have been revised by Bastian in an excel-
lent monograph, in which several new
genera and 100 new species are described
and figured; to which we must refer those
who are specially interested in this curious
group.

A small nematoid is very destructive to
young cucumber plants, forming cysts in
the roots. M. Cornu has recorded a similar
disease in the Rubiacese. The genus to
which these nematoids belong has not been
determined.

BIBL. Bastian, Linn. Tr. xxv. p. 73, 1865;
Cornu, Compt. rtndus. 1878-9 ; Beauregard,
Mic. 1880, p. 604.

ANGUINA'RIA, Lamk.(/ExEA, Lamx.).

— A genus of marine Polyzoa, of the suborder
Cheilostomata, and family Eucratiidae.

Char. Cells tubular, erect, scattered, rising
from a creeping fistular fibre adnate to a
foreign base; aperture terminal or subter-
minal. British species : —

A. spatulata. Cells spatulate at the end,
curved, ringed.

A. recta. Cells straight.

A. truncata. Cells truncate at the end,
surface punctate, not ringed.

Four foreign species.

BIBL. Johnston, Sr. Zooph. 292 ; Gosse,
Mar. Zool. ii. 13 ; Busk, Cat. Mar. Polyz.
31 ; Hincks, Polyz. 1880, p. 2.

ANGUINEL'LA, V. Bened.— A genus of
marine Polyzoa, of the suborder Ctenosto-
mata, and family Vesiculariidae.

A. palmata. Palrnately branched, largely
composed of mud; tentacles 12; no gizzard;
British.

BIBL. Gosse, Mar. Zool. ii. 22; Van
Beneden, Bryoz.; Hincks, Mar. Polyz. 1880,
p. 539.

ANGULAR APERTURE.— The angu-
lar aperture of an object-glass is the angle
measured by the arc of a circle, the centre
of which is formed by the focal point of the
object-glass, the radii being formed by the
most extreme lateral rays which the object-
glass admits.

Thus let fig. 16 represent a perpendicular
section of the lowest combination of an
object-glass of small aperture: a is the

Fig. 16.

Fig. 17.

angle of aperture ; and /, e are the most
oblique rays which the object-glass will
admit ; the angle is measured by the dotted
arc b. In the object-glass of larger aper-
ture, fig. 17, the arc b which measures the
angle is much larger, and the radii repre-
senting the extreme lateral rays are much
more oblique. Hence it is evident that the
object-glass of larger aperture admits all

ANGULAR APERTURE. [

those rays admitted by that of less aperture,
and a certain number of other rays, these
being more oblique.

Measurement of the angle of aperture. — It
is of the utmost importance to know the
angle of aperture of the object-glasses used
in investigations ; because 'the appearances
presented by objects vary according to the
magnitude of this angle, and this variation
must always be taken into account in de-
termining the structure of an object from
its appearance. A particular piece of appa-
ratus is requisite for this purpose (fig. 18),

Fig. 18.

which may easily be constructed as follows.
A rectangular piece of board must be pro-
cured, the shortest sides of which are about
2 inches longer than the body of the micro-
scope, and the longer sides twice this length.
A small hole must then be made opposite
the middle of one of the long sides, at about
half an inch from its margin, and from this,
as a centre, a semicircle must be traced
upon the board, and the semicircular line
divided into 180° ; the portions outside the
semicircle being cut away. The wooden
plate of this form is shown in perspective in
the woodcut. A flat thin piece of wood («)
rather broader than the body of the micro-
scope, a little longer than the radius of the
semicircle and pointed at one end, is then
placed upon the board in such a manner that
the pointed end corresponds with the gra-
duated margin, whilst the other end is
transfixed by a pin (b) which below is driven
into the board. Thus we have a rotating
arm or radius of the semicircle, which may
be compared to the hand of a watch or clock,
the pin forming the centre of rotation. To
the upper surface of this arm are glued two
thin pieces of wood, excavated in the
middle, so as to form supports for the body
of the microscope ; the excavations should
be triangular, the apex being directed down-
wards.

] ANGULAR APERTURE.

When used, the object-glass to be tested
is screwed to the end of the body next the
pin, and so adjusted that its focal point is
as nearly as possible perpendicularly over
the pin. A lamp is placed 2 or 3 yards
from the board and upon exactly the same
level as the axis of the body of the micro-
scope, the straight side of the board being
next the lamp ; and when the arm has been
so adjusted that the pointed end is opposite
90°, the lamp is placed so that the flame is
seen through the body of the microscope.
The eyepiece is next put into the other end.
The arm supporting the body of the micro-
scope is then moved on one side, the eyepiece
looked through in the usual manner, until
the field is seen to be divided into two parts,
a dark and a luminous half; the degree
which the pointed end of the arm coinciilcs
with is then noted, and the arm is moved in
the other direction until the division of the
field is again seen ; the number of degrees
included in the arc thus traversed measures
the angle of aperture.

This is the old method (Lister's), and that
by which object-glasses are still generally
measured; so that, for the purposes of
comparison, it will be found useful.

But it is considered that it gives an
erroneous excess of aperture, from the ad-
mission of rays from lateral pencils, which
should be excluded. Wenham recommends
as a more accurate method, that half the
front lens of the object-glass be covered
with a piece of tin-fo'il. The degrees from
the half lens are then subtracted from those
of the entire lens, and twice the difference
represents the aperture.

A very rough method of determining
whether an object-glass has a small or large
angle of aperture is this : direct the object-
glass, with the lower end towards the eye,
to the sky at a window ; then, keeping the
object-glass fixed, move the eye on one side
until light is no longer visible in the glass.
The extent to which the eye can be moved
round, before the light vanishes, indicates
the extent of aperture.

Another method is described in Car-
penter's l Microscope,' 1868, p. 172, or Ro-
bin, 'Microscope,' 1877, p. 103; also Abbe's
" Apertometer," with figs., in the Jn. Micr.
Soc. 1878, i. p. 19; and H. Smith's "Univer-
sal Apertometer," in the Jn. Micr. Soc. ii.
1879, p. 775 (fig.).

According to Abbe (Crisp), the aperture
of an optical instrument indicates a greater
or less capacity for receiving rays from

ANGULAR APERTURE. [ 45 ] ANGULAR APERTURE.

the object, and transmitting them to the
image.

In the microscopic object-glass, the an-
gular aperture is determined by the ratio
between its focal length and the diameter
of the emergent pencil at the plane of its
emergence from the back lens of the com-
bination.

This ratio is expressed for all media and
all cases by n sine u ; n being the refractive
index of the medium, and u the semi-angle
of aperture. The values of n sine u, for any
particular cases, are the numerical apertures
of the object-glasses, so that in dry object-
glasses n = l; in water-immersion, n— T33;
and in homogeneous immersion object-
glasses, w=r52.

F. Crisp gives a Table of the relation of
the ordinary expression of the angular
aperture to the numerical (Jn. Mic. Soc.
1881, i. p. 325). Thus :

180° aperture = 1° num. apert. ;
98° = 0°-76; 60°=0°-50 &c. The
corresponding immersion-apertures are also
given in this Table.

As an object-glass of large aperture ad-
mits a greater number of oblique rays than
one of less aperture, the central rays being
in nowise interfered with, so the total num-
ber of rays admitted is greater, and objects
will thereby be more brilliantly illuminated.
This is one of the advantages gained by the
use of an object-glass of large aperture ; and
the explanation applies especially to its use
in the examination of opaque objects, in re-
gard to which it can be readily understood
that a greater number of the rays reflected
from all parts of an object being admitted,
will render it more luminous and distinct.
In this case the same effect would be pro-
duced by condensing an additional amount
of light upon the object.

There is, however, another far more im-
portant use of large angular aperture in an
object-glass. It was first found by Goring
that the longitudinal and transverse lines
upon the scales of Lepidopterous and other
insects could be seen under certain object-
glasses, but not under others ; and that the
power of displaying these, or the penetrating
power of the object-glass, as it was called,
depended upon the magnitude of the an-
gular aperture. The same has since been
found the case with the markings upon the
valves of the Diatomacea3, thus :

1. If the valve of a Pleurosigma angulatum
be examined under an object-glass of 1-4
or 1-8 of an inch focus, and an angular

aperture of 60° or 70°, as illuminated by
the ordinary light of the mirror, nothing
more is seen than the more or less coloured
valve with a distinct outline, the central
line and the nodules; and no change is
produced in the appearances, however in-
tensely the object may be illuminated. But
if an object-glass of larger angular aperture
be used, a number of fine dark parallel lines
are seen traversing the valve. Hence the
object-glass of larger aperture possesses a
particular power of rendering indications of
structure evident, which is not possessed by
the one of less aperture.

2. If, in the same experiment, the mirror
be brought towards one side of the stage,
and the light be then thrown upon the ob-
ject, the lines will become more distinct if
previously visible, and frequently visible
when not so before.

3. Placing a stop in the condensing lenses
of the achromatic condenser or object-glass
will increase the distinctness with which the
markings are seen, if already visible, and will
frequently render them visible when not so
before.

These experiments show, that using an
object-glass of large aperture in the exami-
nation of an object, bringing the mirror to
one side, and placing a central stop in the
object-glass or the condenser, or in both,
produce the same effects, viz. that of render-
ing the markings upon an object visible
when not so previously, or of rendering
them more distinct if previously visible.
And it is evident that the alterations of the
conditions under which the object is exa-
mined in the above experiments, involve
simply the viewing of the object when illu-
minated entirely or more completely by ob-
lique light. For an object-glass of large
aperture admits more oblique rays than one
of less aperture, the central rays being in
nowise interfered with ; inclining the mir-
ror to one side, causes all the rays which
are reflected from it to become oblique ;
and the use of central stops excludes all
the central rays, so that only the oblique
rays are admitted. Hence the visibility or
greater distinctness of the markings upon
an object depends upon its illumination by
oblique light.

Experiment also shows that the degree of
obliquity of the light requisite varies with
the delicacy or fineness of the markings,
being greater as these are more delicate ; so
that the most delicate markings require the
most oblique light which can possibly be

ANGULAR APERTURE. [ 46 ] ANGULAR APERTURE.

obtained, to render them evident, and the
angular aperture of the object-glass must ne-
cessarily be proportionately large, otherwise
none of these oblique rays could enter it.

In attempting to explain these pheno-
mena, we may take the opportunity of exa-
mining somewhat minutely the reason why
objects become visible to us under various
circumstances.

The ordinary cause of objects becoming
visible to us under the microscope, is that a
certain number of the rays of light trans-
mitted through or incident upon them or
their parts, either become absorbed, re-
fracted or reflected. Hence the parts at
which refraction or absorption occurs may
become either coloured or dark, whilst those
which transmit or reflect the light become
luminous. We shall leave the cases of ab-
sorption and reflection out of the question
at present, and consider only those of re-
fraction.

If the parts which refract the light are
large in proportion to the power of the ob-
ject-glass, and of irregular form, they will
refract a certain number of rays, so that
these cannot enter the object-glass, and
they will hence become dark, and will sha-
dow out, as it were, in the image formed of
the object, the structural peculiarities of the
object. But if the parts are minute, of a
curved form and approximative^ symme-
trical, their lenticular foci will produce a
luminous or dark appearance, according to
the relation of the foci to that of the object-
glass. Thus, the parts of an object may ap-
pear dark and denned, from the refraction of
the light from the field of the microscope ;
also, from the concentration or dispersion of
portions of the light by these parts, all the
rays being admitted by the object-glass, or
entering the field.

Another condition, rather physiological
than optical, is concerned in the Question
of the distinctness with which an object is
seen, nay, even of its absolute invisibility. It
consists in the relation which the luminous-
ness or darkness of an object bears to that
of the field or background upon which it is
apparently situated ; and all objects, even
those seen with the naked eye, may be re-
garded as viewed upon a background or
field, comparably to an object viewed in the
field of the microscope. The familiar in-
stance of the visibility of the stars by day
from the bottom of a coal-pit, whilst invi-
sible from the surface of the earth, may
serve to illustrate this point. The same

phenomenon is constantly met with in
microscopic investigations ; thus it is well
known that parts of structure which are
visible most clearly by the light of a lamp in
a dark room, cannot be distinguished when
the room is illuminated by ordinary day-
light ; and luminous objects are best seen
on a black ground, and dark objects on a
light ground.

The refraction of the light out of the field
of the microscope or beyond the angle of
aperture of the object-glass, is the ordinary
cause of the outlines of objects becoming
visible ; and in these cases an increase of the
angular aperture of the object-glass will im-
pair their distinctness, because it will allow
of the admission of those rays which would
otherwise have been refracted from the field,
and the margins will become more luminous
and less contrasted with the luminous field.
All that is required here is that the object-
glass shall be achromatic, and that the mar-
ginal rays shall not be decomposed, so that
any of the coloured rays should enter the
field ; in which case, the margins of the ob-
jects would appear coloured instead of black,
and thus the contrast requisite for distinct-
ness would be lost.

But in certain objects, the irregularities
of structure are of such extreme minute-
ness, or the difference of the refractive
power of the various portions of the struc-
ture is so slight, that the course of the rays
is but little altered by passing through
them; and under ordinary illumination,
all the rays will enter the object-glass;
neither are the lenticular foci sufficient to
map out the little light or dark spots in the
field of the microscope according to their
relation to that of the object-glass.

Let us take the instance of an object with
minute markings on the
surface, as the valve of a
Pleurosigma. These are
so minute, that when the
light reflected from the
ordinary mirror is used,
the rays passing through
the depressed and the un-
depressed portions are not
sufficiently refracted to
cause either set to be ex-
cluded from the object-
glass, consequently both
sets will enter it (ng. 19).
But on transmitting ob-
lique light through the
object, as represented in fig. 20, one set of

ANGULAR APERTURE. [ 47 ] ANGULAR APERTURE.

the rays will be refracted so as not to enter
the oDJect-glass, whilst the other set will
gain admission ; thus the two parts, which
have differently refracted the rays, will be-
come distinct. If the markings were more

Fig. 20.

delicate, or the difference between the re-
fractive power of the two portions of the
valve were less than that represented in
fig. 20, both sets would enter the object-
glass. But on rendering the light still more
oblique, one set would be again excluded,
from being refracted out of the field. Hence
it is evident why the angular aperture of
the object-glass must be larger, as the
markings are finer, or the difference between
the refractive power of the two portions of
tissue is less ; because the obliquity of the
light requisite to cause the exclusion of one
set of the rays will be very great, and the
other set will be too oblique to enter the
object-glass, unless it be of correspondingly
large aperture.

In this way, we were wont to account for
the action of large angles of aperture and
oblique light in rendering visible the finer
markings of objects.

But the entirely new researches of Pro-
fessor Abbe of Jena, confirmed by others,
especially Crisp, Stepheuson, and Nageli and
Schwendener, have entirely altered the
views upon this subject.

According to Abbe's experiments and
mathematical demonstrations, the resolution
of the more minute structural peculiarities
of objects — those of less size than ^Yo °f
an inch — is produced by the superposition
of two images, one of which principally
contains the outlines of the- object, and is
produced according to the ordinary laws of
dioptrics ; while the other, which yields
the finer structural details, arises from the
diffraction (or an equivalent deflection pro-

duced by refraction or reflection) of the rays
within the object, and their interference at
the upper focal plane of the object-glass,
where they produce distinct interference-
images. Unless at least one of the diffrac-
ted beams is admitted by the object-glass,
together with either another beam or the
direct incident pencil, no indication of struc-
ture is visible in the microscopical image.
And the angle of aperture of an object-glass
represents a specific property, entirely dis-
tinct from the magnifying and other pro-
perties of the object-glass.

If the interference-images are stopped off,
or if the angular aperture of the object-glass
is too small, the corresponding details dis-
appear entirely from the microscopic images.

Abbe holds also, that structures of this
minute kind which an object-glass with
direct illumination does not render visible,
are also not visible when the object is in-
clined at any angle whatever to the axis of
the microscope; even when, while lying
perpendicularly to its axis, they are perfectly
resolved by oblique light.

An important result of these views is,
that minute structural details are not, as a
rule, imaged by the microscope dioptric-ally,
in accordance with the real nature of the ob-
ject, and cannot be interpreted as morpho-
logical but only as physical characters : not
as images of material forms, but as signs of
material differences in the nature of the
particles composing the object, so that no-
thing more can safely be inferred from the
image aspresentedto the eye than the presence
in the object of such structural peculiarities
as will produce the particular diffraction-
phenomena on which the images depend
(Abbe).

In regard to the action of oblique light
and angular aperture in relation to colour :
neither oblique light nor large angular aper-
ture possesses any power of rendering co-
loured transparent objects more distinct;
and markings, when arising from the pre-
sence of pigment, are perfectly visible under
an object-glass of small aperture, and the
ordinary light of the mirror.

When objects are examined under im-
mersion-lenses, they appear more brilliantly
illuminated, especially in regard to the finer
details. This is partly to be attributed to
the diminution of the loss of light from re-
flection at the surfaces of the cover and the
under surface of the object-glass; but mainly
to the circumstance that a larger number
of oblique rays are enabled to enter the

ANGULAR APERTURE. [ 48 ]

ANIMAL KINGDOM.

object-glass, from the higher refractive
power of the immersion-liquid, which pro-
duces the effect of an increased angle of
aperture in the object-glass. This admis-
sion of an increased number of oblique rays,
would tend to invalidate the view, that the
more delicate structures are rendered visible
by the removal from the field of certain
olblique rays; but it would favour the
rendering of the markings visible by their
lenticular foci. According to the diffrac-
tion-theory, the admission of a larger num-
ber of diffraction-results would explain the
increased distinctness resulting from the
immersion-arrangements.

Many rather controversial articles on the
relation of the dry- to the immersion-aper-
tures will be found in the M. M. Jn. from
1872 to 1877.

It was noticed by Goring, that although
the lines on the scales of certain insects re-
quired an object-glass of comparatively
large aperture to show them, yet those ex-
isting upon glass micrometers did not so.
But this statement is only partially correct ;
for although the coarser lines upon micro-
meters are well seen under an object-glass
of small aperture with good defining power
and direct light, yet the finest lines upon
Nobert's test-slide require penetrating power
in the object-glass, and oblique light. Thus,
R. Beck found that a ^th-in. object-glass of
120° would show all the 20 sets of Nobert's
lines; when cut down to 110°, it would not
resolve the 20th band ; at 100° the 17th
was the limit ; at 80° the 14th ; and at 60°
the 10th.

Our space will not permit of entering into
further details on this important matter ;
but we shall refer to it again, in its relation
to the markings on the DIATOMACEJE.

Apertures of Object-glasses. — The follow-

ing apertures of (dry) object-glasses may be

taken to represent those usually met with

in good glasses : 2", 14° ; 1", 25 ; £ ", 32

", 400-80°; i",75°-140°; T, 140°;

; ft",
. The

145°-170°; 5y, 160°; and ^y, 150°. e
apertures of the foreign object-glasses are
usually over-estimated by the makers in
their price-lists.

The transverse lines seen upon the scales
of insects are noticed under SCALES of IN-
SECTS. The structure of the valves of the
DIATOMACEJE is discussed under that head ;
see also INTRODUCTION, p. xxxix, I.

BIBL. Lister, Phil. Tr. cxxi. ; Goring,
Micrographia ; Pritchard, Micr. Cabinet ;
R. Beck, Treatise fyc. 19; Wenham, M.

M. J. 1872, viii. 231 & 1876, xvi. 285 ;
id. Jn. Mic. Soc. 1878, i. 321; Abbe
(abridged by Fripp), M. M. Jn. 1875, xiv.
191, 245 ; id. (Theor. d. Mik.) Arch. f. nn'k.
An. 1873, ix. 420; (estimation of aperture)
Jn. Mic. Soc. 1881, i. 388; Apertometer
(figs.), Jn. Mic. Soc. 1880, iii. 20; Helm-
holtz (Theor. Grenze f. d. Leist.), Poggen-
dorff's Ann., Jubelband, 1874, g. 566 ; Ste-
phenson, M. M. Jn. xiv. 3 & xvii.82; Nageli
andSchwendener, Mikr. 1877, p. 82 ; Stokes,
Jn. Mic. Soc. 1878, i. 139; F. Crisp,
Jn. Mic. Soc. 1881, i. p. 303 (full description
and illustrations of Abbe's views) ; Wenham,
Amer. Jn. Micros. 1881.

ANIMALCULE. — A little animal; a
term usually applied to the Infusoria, Ro-
tatoria, &c. It was formerly applied also
to many of the lower Algae. The Latin
term animalculum (plural animalculd) is
frequently met with.

ANIMAL KINGDOM.— In accordance
with our plan, as laid down in the Preface,
we give here a tabular view of the animal
kingdom, so that the position of the various
classes and orders alluded to in various parts
of this work may be readily found. Those
classes, orders, families, and genera to which
particular interest is attached in relation to
structure or other qualities, which the micro-
scope is required to investigate, are specially
treated of under their respective heads.

Kingdom ANIMA'LIA.
Subkingdom I. VERTEBRA'TA.
Class I. MAMMA'LIA.

Order 1. BI'MANA.

Homo, man.
Order 2. QUADRU'MANA.

Simia, ape; Cercopithecus, common
monkey; Semnopithecus, Indian mon-
key.
Order 3. CHEIROP'TERA,

Vespertttio, bat.
Order 4. INSECTI'VORA.

JErinaceus, hedgehog ; Talpa, mole.
Order 5. CARNI'VORA.

Cams, dog and wolf; Ursus, bear;

Felis, lion ; Nasua, coatimondi.
PINNIPEDIA. Phoca, seal.
Order 6. CETA'CEA.

Bal&na, whale ; Plioccena, porpoise.
SIRENIA. Halicore, dugong ; Manatus,
manatee.

Order 7. PACHYDER'MATAf.

Equus, horse ; Sus, hog ; Hippopota-
mus ; Choir opatamu8.

ANIMAL KINGDOM.

ANIMAL KINGDOM.

PROBOSCIDEA. Elephas, elephant.
Order 8. RuMiNAN'xiAf.

Bos, ox ; Camelus, camel ; Cervus, deer ;

Capra, goat; Ovis, sheep.
Order 9. EDEXTA'TA (BRUTA).

Dasypus, armadillo ; Brady pus, sloth.
Order 10. RODEN'TTA.

Cavia, guinea-pig ; Lepus, hare ; Mus,
mouse and rat; Sciurus, squirrel;
Castor, beaver and musquash ;
Chinchilla.
Order 11. MARSUPIA'LIA.

Macropus, kangaroo; Didelphys, opos-
sum.
Order 12. MONOTBEM'ATA.

Ornithorhynchus, duck-billed platypus.

ft These two orders form the Class Ungu-
lata of some authors.

Class II. AVES, birds.

a. CARINAT.E.

Order 1. RAPTO'HES; birds of prey.

Aquila, eagle ; Stria:, owl.
Order 2. INSESSO'RES (PASSERES) ; per-
chers.

Fringilla, finch ; Hirundo, swallow ;

Turdus, thrush, blackbird.
Order 3. SCANSO'BES ; climbers.

Cuculus, cuckoo ; Psittacus, parrot.
Order 4. GALLI'NJE ; RASO'BES.

Gallus, fowl ; Columba, pigeon.
Order 5. GBAXLATO'BES ; waders.

Orus, crane.
Order 6. NATATO'BES ; swimmers.

Larus, gull; Anas, duck; Anser,
goose.

b. RATITJE.

Order 7. CURSO'BES j runners.
Struthio, ostrich.

Class III. REPTILIA, reptiles.

Order 1. CHELO'NIA.

Testudo, tortoise.
Order 2. SAU'RIA.

Lacerta, lizard.
Order 3. OPHID'IA.

Boa; Coluber, snake.
Order 4. CROCODIL'IA.

Crocodilus, crocodile.

Class IV. AMPHIBIA.
Order 1. ANU'BA.

Rana, frog ; Bufo, toad.
Order 2. URODE'LA.

Triton, water-lizard ; Mcnopoma', Pro-
teus.

Class V. PISCES, fishes.

Order 1. GANOI'DEA.

Lepidosteus, bony pike; Sturio, stur-
geon.
Order 2. PLACOI'DEA.

Carcharias, shark ; Raia, skate.
Order 3. CTEXOI'DEA.

Perca, perch.
Order 4. CYCLOI'DEA.

Salmo, salmon; Clupea, herring; Q/-

prinus, carp.
Order 5. CYCLOS'TOMI.

Petromyzon, lamprey.
Order 6. LEPTOCAR'DEA.

Amphioxus, lancelet.

Subkingdom II. MOLLUSCA.

Class I. CEPHALOP'ODA.

Sepia, cuttle-fish ; Nautilus.
Class II. GASTEROP'ODA.

Helix, snail; Limax, slug; Littorina,

periwinkle.
Class III. PTEROP'ODA.

Clio.

Class IV. CONCHIF'ERA (LAMELLIBBAN-
CHIA'TA), shell-fish.

Ostrea, oyster ; Mytilas, mussel.
Class V. BRACHIOP'ODA.

Terebratula, lamp-shell.
Class VI. TUNICA'TA.

Ascidia, Salpa, Botryllus, Amaroucium.
Class VII. POLYZO'A (BRYOZOA), Sea-
mats, &c.

Subkingdom III. ARTHBOP'ODA (Arti-
culata).

Class I. CBUSTACEA, crabs, lobster, &c.
Order 1. DECAP'ODA.

Cancer, crab ; Astacus, lobster and cray-
fish.
Order 2. STOMAP'ODA.

Squilla.
Order 3. AMPHIP'ODA.

Gammarus, freshwater shrimp.
Order 4. ISOP'ODA.

Oniscus, wood-louse; Asellm, water

wood-louse ; Limnoria.
Order 5. PHYLLOP'ODA.

Branclripus, Artemia.
Order 6. CLADOC'EBA.

Daphnia, wrater-fleas.
Order 7. COPEP'ODA.

Cyclops.
Order 8. OSTBACO'DA.

Cypris.

ANIMAL KINGDOM.

C

ANIMAL KINGDOM.

Order 9. CIBBIPE'DIA (Cirrhopoda).

Balanus, acorn-shell ; Lepas, barnacle.
Order 10. SIPHONOS'TOMA (Ichthyo-

phthira)-, fist-lice.
Order 11. PCECILOP'ODA.

Limulus, king-crab.

Class II. ABACHNI'DA, spiders.

Order 1. ABANE'IDA.

Aranea, house-spider ; Epeira, garden-
spider.
Order 2. PEDIPAL'PI.

Scorpio, scorpion.
Order 3. SOLIF'UGA.

Galeodes.
Order 4. PSEUDOSCOBPIO'NES.

Chelifer.
Order 5. PHALAN'GIDA.

Phalangium, harvest-spinner.
Order 6. ACARI'NA.

Acarus, mites. |

Order?. TABDIG'BADA (Colopodd); water-
bears.
Order 8. PYCNOGON'IDA (Polygonopodd).

Pycnogonum.

Class III. MYBIAP'ODA.

Order 1. CHILOGNA'THA.

lulus.
Order 2. CHILOP'ODA.

LithoUus.

Class IV. INSECTA, insects,

Order 1. COLEOP'TEBA.

Beetles.
Order 2. OBTHOP'TEBA.

Blatta, cockroach ; Acheta, cricket.
Order 3. HEMIP'TEBA.

Cimex, bug ; Aphis ; Apkrophora, cuc-
koo-spit.
Order 4. NEUBOP'TEBA.

Ephemera ; Libellula, dragon-fly.
Order 5. LEPIDOP'TEBA.

Butterflies and moths.
Order 6. HYMENOP'TEBA.

Apis, bee ; Vespa, wasp ; Formica, ant.
Order 7. DIP'TEBA.

(Estrus, bot-fly ; Musca, house-fly.
Order 8. STBEPSIP'TEBA, bee-parasites.

Stylops.

Order 9. APHANIP'TEBA {Siphonaptera ;
Suctoria).

Pulex, flea.
Order 10. ANOPLU'BA.

Pediculus, louse.
Order 11. THYSANU'BA.

Lepisma, Podura.

Subkingdom IV. VEBMES.

Class I. ANNULA'TA (Anellida).

Order 1. SETIG'EBA.

Lumbri'cus, earthworm; Nais; Ttt'bi-

fex; Aphrodi'ta.
Order 2. SUCTO'BIA.

Hirudo, leech.
Order 3. TUBBELLA'BIA.

Planaria.

Class II. ROTATOBIA (Rotifera).

Class in. ENTOZO'A.

Order 1. CESTOI'DEA, Tape-worms.
Tcenia, Bothriocephalus, Acanthocepha-
lus (Cystica, Cysticercus, Echinococ-
cus, Cosnurus).
Order 2. TBEMATO'DA.

Dis'toma, fluke, (Cercaria) ; Gyrodac-

tylus.
Order 3. ACANTHOCEPH'ALA.

Echinorhynchus.
Order 4. NEMATOID'EA.

Tricocephalus, Filaria, Ascaris (O.ry-
uria), Anguillula, Gordius, Trichina.

KADI AT A.

Subkingdom V. ECHINODEB'MATA.

Class I. A'PODA.

Chirodota,
Class II. PEDICELLA'TA.

Asterias, star-fish ; Echinus, sea hedge-
hog ; Ophiocoma ; Spatanyus.

Subkingdom VI. CCELENTEBA'TA (Zoo-
phytes).

Class I. ACTINOZO'A (Anthozoa, Polypi}.
Order 1. ZOANTHA'BIA.

Actinia, sea-anemone ; Sagartia', Mad-

repora, stone-coral.
Order 2. ALCYONA'BIA.

Akyonium, Gorgonia, sea-fan.

Class II. HYDBOMEDU'SJE (Hydrozo'a}.

Order 1. DISCOPH'OBA (Acaleplice).

Medu'sa, sea-nettle, jelly-fish j Cyancea.
Order 2. HYDROI'DA.

Hydra', Sertularia-, Campanularia.
Order 3. SIPHONOPH'OBA.

Physalia, Portuguese man-of-war.

Class III. CTENOPH'OBA.

JBeroe.

ANIMAL KINGDOM. [ 51 ]

Subkingdom VII. PROTOZO'A.
Class I. LMFUSOK/IA.

Class II. RHIZOP'ODA.
Order 1. RETICULA'RIA.
Gromia, Foraminifera.
Order 2. RADIOLA'RIA.

Actinophrysy Acanthometra ; Polycys-

tina.

Order 3. LOBO'SA.
Amaha, Arcella.
Order 4. GREGABI'NLDA.

Class III. SPONGIDA.
MONEBA.

ANNUAL RINGS.

BIBL. Rymer Jones, An. Kingd.; Todd's
Cycl. of Anat. ; Siebold and Stannius, Lehrb.
d. vergl Anat. ; D'Orbigny, Diet. d'Hist.
Ned. ; V. d. Hoeven, Handb. d. Zool. ; Owen,
Hunt, Lect. ; Carpenter, Compar. Physiol. ;
Cuvier's An. Kingd., by Blyth, Mudie,
Johnston, Carpenter, and Westwood ; Vogt,
Zool. Itriefe ; Gosse, Mar. Zool. ; Carus, Ic.
Zoot. (Invertebrata) ; Blanchard, Regne
Animal ; Leydig, Lehr. d. Hist. ; Baird,
Nat. Hist., 1863; Green, Cceknterata, 1863;
Van Beneden, Anat. Comp. ; Strieker, Gew.
d. Memch. u. Thiere, 1872 ; Hackel, Gen.
Morph. ; Chenu, Encycl. d'Hist. Nat. (8000
figs.), 1866; Thome, Zool., 1875; Hayek,
Zool, 1877 ; Bronn^'e Klass.d. Thiei-reichs,
1880; Clans, Grundzuye d. Zool, 1875;
Schmidt, Handb. d. vergl Anat., 1876;
Schmarda, Zool, 1878; Nicholson, Man.
Zool, 1878; Gegenbaur, Vergl Anat., 1878 ;
Huxley, Inv. $ Vert., 1872 ; R. Lankester,
Qu. M. Jn. 1877, xvii. p. 399 ; Pascoe, Zool
Class., 1880; M'Alpine, Zool, 1881.

ANISONE'MA, Duj.— A genus of Infu-
soria, belonging to the family Tliecaniona-
dina (Flagellata, Kent).

Char. Body colourless, oblong, more or
less depressed, covered with a resisting
tegument, from an aperture in which two
filaments emanate — one flagelliform and
directed forwards; the other thicker, trail-
ing and retracting the body of the animal ;
movement slow. 2 species : —

A. acinus (grande). Movement directly
forwards, colourless; length 1-1280 to
1-810" ; fr. wat. among Conferva.

A. sulvata (PI. 23. f. 12). Movement
vacillating in a circle ; colourless ; fr. wat. ;
length 1-1100".

3 other species. Dujardiu suggests that
the Bodo gmndis of Ehrenberg is referable

to one of these species, as also to the genus
Heteromita, Duj.

BIBL. Dujardin, Infos, p. 345 ; Kent, Inf.
p. 434.

ANKISTRODESMUS, Corda (Rapid-
dium, Rabenh.). — A genus of Desinidiacege.

Char. Cells elongated, attenuated, entire,
aggregated into faggot-like bundles.

The cells only differ from those of Closte-
rium in their Aggregation. Species : —

A.falcatus, Corda (Rhaphidium fascicu-
laturn, Kiitz.). Cells numerous, crescent-
shaped: aquatic; length 1-549", breadth
1-7353"; common. (PI. 14. fig. 47.)

A. fusiformis, Corda. I n , , ,

A.conmlutm, Corda. f Carlsbad-

BIBL. RaKs, Brit. Desmidiece, pp. 179
and 222 ; Corda, Alman. d. Carlsbad, 1835,
p. 121, 1838, p. 199.

ANNUAL RINGS. — The concentric
lines seen in transverse sections of Dicoty-

Fig. 21.

Cross section of a Dicotyledonous stem with annual
ringa.

ledonous stems (fig. 21) generally indicate
successive annual additions to the woody
structure, and in these cases depend on the

Fig. 22.

Magnified cross section of stem of Finns, exhibiting
parts of three annual rings, 1, 2, 3.

difference of the character or condition of
the tissues produced at different seasons.

E2

ANNULATA.

ANNUL AT A.

Ordinarily there are a number of ducts
grouped near the inner part of each con-
centric layer of wood, as in the Oak. In
the Sumach a layer of cellular tissue occurs
at the boundary of each ring. In the Coni-
fers, the markings result from the greater
thickness of the secondary deposits on the
walls of the cells in the outer part of each
layer, no ducts existing in their wood (fig.
22).

It seems that these rings cannot be taken
strictly as annual rings in all trees, especially
in those of equable climate, since they
appear to depend upon external influences
affecting the activity of vegetation; and
thus, even in temperate climates, a great
loss of foliage in tne summer, followed by
recovery, may produce two rings in one year.
In moist tropical climates, where the leaves
reappear almost continuously, the rings pro-
bably answer to periods of great renewal of
foliage.

ANNULA'TA, AneUida.— The class of
red-blooded worms, &c.

Char. Elongated animals, living in water
or moist earth, not parasitically within other
animals; body usually ringed or iointed ;
feet not jointed, and frequently replaced by
bristles or retractile setigerous tubercles.
Respiration effected either by external
branchiae or by internal vesicles, or by the
skin itself. Distinct organs of circulation
present, contractile vessels replacing a
heart. Nervous system consisting of a
single or double ventral cord, furnished
with ganglia at intervals, and encircling
the oesophagus above.

The skin consists of a very delicate struc-
tureless and transparent epidermis, beneath
which (in Hcemochnris (Piscicola), Clepsine,
and Nephelis) there is a layer of cells, which,

of a fenestrated membrane (PI. 49. fig. 16).
The cells (PI. 49. fig. 166) leave spaces
between them which appear like holes ;
but the addition of acetic acid brings to
light in each space a distinct nucleus (PI. 49.
fig. 16 c), and in very young animals the
clear spaces are distinct cells, distinguish-
able from the surrounding cells by their size
and containing numerous clear vesicles as
well as a nucleus. The smaller cells contain
a nucleus and numerous nuclear granules.
Beneath this cellular layer are numerous
large fat-cells, pigment-cells, and connective
tissue, the latter consisting of a transparent,
homogeneous, semisolid mass. A layer of
fin 3 but firm fibres, crossing each obliquely,

is said to be sometimes met with beneath
the epidermis and forming a corium or true
skin.

In the Turbellaria, the outermost cuta-
neous layer consists of ciliated epithelium.
The opalescent and of ten beautifully coloured
skin of many of the Annulata does not gene-
rally owe its tints to distinct pigment, but
to iridescence produced by the fibres.

The rings of the body are usually furnished
with bristles or hairs, sometimes arranged in
tufts, at others covering the greater part of
the surface of the body.

The bristles are most exquisite objects
for microscopic observation, displaying the
greatest variety of form, constituting lances,
spears, knives, saws, sickles, hooks, &c., of
innumerable elegant shapes, often curiously
jointed, and usually fashioned out of an
elastic material that rivals the clearest glass
(Gosse). Sometimes foliaceous appendages
cover the body like, scales. Most of the
Annulata are covered with a kind of mucus,
secreted by the cutaneous glands; some
live in leathery tubes or sheaths ; in others
a case is made by the consolidation of the
secretion from some part of the skin with
fragments of shells, grams of sand, &c. ; in
others, again, the calcareous tubes appear
to be wholly secreted by a portion of the
cutaneous surface.

The muscular system is usually well de-
veloped. The muscular fibres are in some
arranged in three layers, an outer consisting
of annular, an inner of longitudinal, and an
intermediate of oblique fibres ; in others
there is an outer layer of oblique fibres, an
inner of longitudinal, with annular fibres at
the two ends of the body. The muscular
fibres consist of cylinders, the transverse
section of which is rounded (PI. 49. fig. 17«),
flattened or incurvated (PI. 49. fig. 176)»
They are covered externally by a delicate
sheath or sarcolemma (PI. 49. fig. 186). TJie
cylinders themselves consist of a clear, homo-
geneous, cortical substance (PL 49. fig. 18«),
and an internal cavity (c), the latter being
filled with a finely granular substance, in
which scattered nuclei are imbedded (PI. 49.
fig. 17c). At the two ends of the bodv,
the muscular fibres branch dichotomously
(PL 49. fig. 19 c). The fibres are usually
smooth, but sometimes longitudinally or
transversely striated; this appearance arising
either from folds in the sarcolemma or proper
sheath, or from the granules being arranged
in linear series.

In the Turbellaria, the muscular system

ANNULATA.

ANNULATA.

is but slightly developed, the tissue beneath
the skin consisting of globular masses re-
sembling the general parenchyma of the
body ; and in this, peculiar cellular bodies
are often imbedded, resembling the urti-
cating organs of the polypes. These enclose
six, eight, or more 'rod-shaped bodies,
which are sometimes parallel with each
other, sometimes somewnat spirally curved.
The cell-membrane of these bodies subse-
quently disappears, and they frequently
project beyond the skin. Leydig figures
similar rod-shaped bodies as occurring in
the nuclei of the fat-cells situated beneath
the skin.

In many of the Annulata, the muscular
fibres are grouped into distinct bundles,
serving to move the bristles, parts of the
mouth, &c.

Beneath the skin at the ends of, or all
over the body, a number of peculiar glands
exist ; these consist at the closed end of a
nucleated cell (PI. 49. fig. 19 id), and a
long, somewhat coiled duct opening at the
surface of the body.

The nervous system consists of a longi-
tudinal, single or double series of ventral
ganglia, connected by longitudinal cords;
the uppermost ganglion lies above the oeso-
phagus, and the two cords which connect it
with the second ganglion encircle this organ.

The iippermost ganglion is enveloped in
a neurilemnia consisting of longitudinal
and transverse fibres, and not unfrequently
peculiar pigment-cells. The cords and
filaments are composed of extremely deli-
cate primitive fibres, between which, in
the ganglia, ganglion-globules are situated.
The filaments distributed to the body arise
principally from the ganglia.

Many of the Annulata are furnished with
eyes ; these are usually denoted by the
brown, black, or red spots seen upon various
parts of the body. It is a disputed point
whether all these represent true eyes or
not ; but Quatrefages has described a lens,
transparent cornea and vitreous humour in
some of them, and he has no doubt that the
red points found at the sides of each ring in
several species of Nais are true eyes.

In some Annulata, no distinct head is
present ; in others this is distinguishable by
its form, and is furnished with eyes and one
or more filaments, which are regarded as
antennae. In those in which the head is not
distinct, the mouth is situated at the anterior
end of the body ; in the others the mouth is
on the ventral surface, and is furnished with

a muscular proboscis. The mouth is usually
surrounded by turgid lips, and sometimes
possesses a distinct dental armature (see
HIRUDO). The oral aperture is frequently
surrounded by a number of erectile tentacles
or cirri.

The intestinal canal is usually straight,
and furnished with lateral appendages, or
constricted at intervals ; sometimes a sepa-
rate oesophagus, stomach and intestine are
distinguishable. The inner, and sometimes
the outer surface of the alimentary tube is
covered with ciliated epithelium. A yellow
or brown glandular layer surrounding: the
alimentary canal represents the liver.

The general arrangement of the cir-
culatory system is, that two main vascular
trunks, one dorsal, the other ventral, tra-
verse the body longitudinally ; and the red
or green blood moves in the dorsal vessel
from behind forwards, whilst in the abdo-
minal vessel it moves from before back-
wards; these trunks being connected by
transverse vessels or meshes of them. The
anterior portion of the dorsal vessel is
usually broader, and appears to form the
rudiments of a heart.

The respiration of the Annulata is effected
either by the skin ; by external gills in the
form of tentacular filaments or tufts, some-
times ciliated ; by ciliated depressions, or
by vesicles at the sides of the body. The
internal convolute ciliated canals, or water-
vessels, which were formerly considered
respiratory organs, are now regarded as
secretory tubes. In many instances a
transparent colourless liquid occupies the
interstices between the skin and the organs
of the body ; this contains colourless (rarely
coloured) corpuscles much resembling the
colourless corpuscles of the Vertebrata, and
is considered by some to represent the true
blood.

The Annulata are propagated by trans-
verse division, by gemmation, and by means
of sexual organs. The embryos are at first
minute, rounded, and partially covered with
vibratile cilia.

Order 1. CHJETOPODA (SETIGERA). Body
ringed, elongate, with feet or setigerous
rudiments of them ; external branchiae
usually present.

Order 2. SUCTORIA (APODA). Body
elongate, ringed, without bristles or foot-
like tubercles ; locomotion by sucking-disks ;
no external branchiae.

Order 3. TURBELLARIA. Body bilateral,
soft, covered with vibratile cilia, not seg-

ANODUS.

ANOPLURA.

merited; eyes distinct; sexless or herma-
phrodite.

BIBL. Siebold, Lehrb. d. vergl. Anat. i. ;
Jones, An. Kinf/d.; V. d. Hoeven, Handb.
d. Zool. i. ; Milne-Edwards, Todd's Cyc. of
Anat. fyc. ; Johnston, Brit. Anell. ; Gosse,
Mar. Zool. \.] Vogt, Zool. Brief e ; Claparede,
An. Chetopod. (Qu. M. Jn. 1869, p. 306) ;
id. Ann. N. H. 1867, xx. p. 337 j Ehlers,
D. Borstenwiirmer, 1869 ; Agassiz, Ann. N.
H. 1867, xix. p. 242 ; Quatrefages, Suites a
Buffon ; Gegenbauer, Vergl. An. 1878 ; R.
Lankester, An. N. H. 1871 ; Art. Anellida,
Enci/cl. Brit. 1875, ii. ; Marion, M. M. Jn.
1875, xiv. 17 (coloured corpuscles in blood) :
Pascoe, Zool. 1880, p. 58 ; Halley, Turlell.
1880 ; Wilson, An. N. H. 1880, vi. 407
(devel.).

AN'ODUS, Br. & Sch. = SELiGEP.iA.

ANCECTAN'GIUM, Br. & Sch.=ZY-

GOPON.

ANOMALPNA, D'Orb.— With some ex-
ceptions (as An. elegans, D'Orb., which is a
small Discorbina} the Anomalince are some-
what biconvex TruncaiuUna, neat, discoidal,
and subnautiloid, with nearly as much con-
vexity of the chambers on the lower as on
the upper side of the shell. Abundant, both
recent and fossil.

BIBL. D'Orb., For. Foss. Vienn. p. 169 ;
Carpenter, For. p. 208.

ANOMALO'CERA, Temp.— A genus of
Entomostraca, of the order Copepoda and
family Diaptomidoe.

Char. Head distinguishable from the
body, with a bifid beak and a hooked spine
at the base on each side ; thorax with six,
abdomen with four segments; foot-jaws
three pairs ; last pair of legs differing from
the others ; eyes single, pedunculated in the
male ; right superior antenna with a swollen
hinge-joint (in the male); inferior antennae
not branched, three-jointed, basal joint with
a slender twig. 1 species : —

A. Patersonii (PI. 16. fig. 6, the male).
Marine.

BIBL. Templeton, Tr. Entom. Soc. vol. ii.
1837; Baird, Brit. Entomostr. p. 229.

ANOM'ODON, Hook, and Taylor. See
NECKERA and HYPNUM.

AN'OPHRYS, Cohn.— A genus of Holo-
trichous Infusoria,

Char. Eree swimming, elongate-ovate,
pointed and curved in front, rounded
behind; a fascicle of longer and stouter
cilia issuing from the ventral oral cleft.

A. sarcophaga (PI. 53. fig. 6). In salt
water, with decaying animal matter.

BIBL. Kent, Infus. p. 511.
ANOPLOPH'ORA, Stein (Opaline-pi.').
— A genus of Holotrichous Infusoria.

Char. Body elongate or ovate, nucleus
band-like, axial ; contractile vesicles evi-
dent.

The (15) species are intestinal parasites
of No-is, Lumbricns, and other Invertebrata.
BIBL. Kent, Infus. p. 663 ; Stein, Inf.
ANOPLU'RA.— An order of Insects;
sometimes termed Parasitica or Epizoa.

Char. Legs six ; wings none ; parasitic,
and not undergoing metamorphosis ; eyes
two, simple, or none.

These insects are parasitic upon mammals
and birds, and are commonly known as lice.
The order is thus subdivided : —
Subord. HAUSTELLATA (RHYNCHOTA).
Mouth with a tubular, very short
fleshy haustellum.

Fam. PEDICULIDJE. Antennae five-
jointed.
Gen. Phthirius. Anterior legs for

walking, posterior for climbing.
Pediculus. Legs all for climbing ;

abdomen of seven segments.
Pedicinus. As Pediculvs, but abdomen

of nine segments.

Hcrmatopinm. Legs all for climbing ;
abdomen of eight or nine segments.
Hcematomyzus. Claws single.
Subord. MANDIBULATA (MALLOPHAGA).

Mouth with two horny mandibles.
Fam. PHILOPTEBLDJE. Antennae fili-
form, maxillary palpi none.
Philopterus. Antennae five-jointed ;

tarsi two-jointed, claws two.
Trichodcctes. Antennas three-jointed ;

tarsi two-jointed, with one claw.
Fam. LIOTHEID^E. Antennas clavate ;

maxillary palpi conspicuous.
Liotheum. Tarsi two-jointed, with two

claws.
Gyropus. Tarsi two-jointed, with one

claw.

It appears that although the Anoplura do
not undergo metamorphosis as in the more
perfect insects, consisting of larva, pupa and
imago, widely diflering from each other in
gener.nl appearance, habits, and functions,
yet a series of semitransformations takes
place in the shedding of the skin a definite
number of times, by which the individual
acquires a greater symmetry of form, and
most probably a greater perfection of parts
or organs.

BIBL. Nitzsch, Germar and Zinckerfs
Mag. d. Entom. iii. ; Burmeister, Gen.

ANOUBELLA.

ANTENNAEIA,

p.

M

Insect.; Leach, Zool. Misc. iii. ; Gurlt,
Thierheilk. viii.; Denny, Mon. Anopl. Brit.]
id. (Chinese}, Qu. Mic. Jn. 1864, p. 18;
Walckenaer, Hist. d. Insect, xiii. ; Landois,
Sieb. fy Kdll. Zeits. 1805 (Qu. M. Jn. 1866,

34) ; Murray, EC. Entomol. 1879, p. 375 ;

egnin, Parasites, 1880.

ANOUKELLA, Bory and DUJ.=ANU-
A, Ehr.

ANTEN'N^E, of Insects.— The two
moveable jointed organs, situated on the
head, near the eyes (PL 33. figs, la, 3 a,
24 a, and figs. 7 to 21 inclusive).

The form, number of joints, &c. of the
antennae are used as characters for distin-
guishing the genera and species of Insects.

Three parts are generally recognizable in
the antennae : 1, the scapus or basal joint
(figs. 10, 18, and 19 a} is often very long,
and is connected with the torulus, or part
upon which it moves, by a ball and socket
articulation ; 2, the pedicella or second joint
(the same figs., b), which is mostly minute
and nearly spherical, allowing of the freest
motion, and supporting the remaining por-
tion of the antennae, which forms, 3, the
clavola (figs. 10 and 18 c). The principal
terms applied to the antennae according
to the form and arrangement of the joints
of the clavola are these : —

They are called setaceous when the succes-
sive joints gradually diminish in size from
the base to the apex, as in the families
Achetidae, Blattidae, and Gryllidse (fig. 7) ;
ensiform when the successively diminishing
joints are angular at the sides, forming a
sword-like organ, as in some of the Locust-
idae (fig. 8) ; fKform when all the joints of
the clavola are of uniform thickness, as in
the Carabidae (fig. 9) ; moniliform when the
joints are spherical or rounded, as in the
Tenebrionidae and Blapsidae (fig. 10) ; ser-
rated when the joints appear like inverted
triangles, with the inner margin more pro-
duced than the outer, as in some of the
Elateridae (fig. 11) ; imbricated when the
acute base of each joint is inserted into the
middle of the broad apex of the joint behind
it, as in the Prionidae (fig. 12); pectinated
when each joint is developed on one side
into a process or spine, as in the Lampyridafi
(fig. 13); bipectinated when a process or
spine exists on each side of the joints, as in
the Bombycidae (fig. 14) ; fabellate when
each of the processes is flattened, and nearly
as long as the whole of the succeeding joints
taken together, as in some of the Elateridae
(fig. 15) ; clavate when the clavola ends in a

gradually formed knob (fig. 16), or capitate
when the knob is suddenly formed (fig. 17),
as in the Pentamerotis Coleoptera ; plumose
when one or more minutely pectinated
branches arises from the joints, as in some
of the Muscidae (fig. 20), or when tufts of
capillary filaments arise from the joints, as
in the Culicidae (fig. 21) ; lamellate, as in the
lamellicorn Coleoptera, when the knob is
composed of a number of lamellae or plates
(fig. 18 d), anAperfoliate when the joints of
the knob are separated slightly from each
other by a minute foot-stalk. There are
many curious variations in the structure of
the antennae ; thus, in some of the Muscidae,
the filamentous portion represents the true
clavola, while the larger lobe is simply an
appendage (fig. 20) ; in Globaria Leachii
the pedicella is not a small rounded joint,
but is elongated like the scapus (fig. 19 6),
whilst the clavola (c) ends in a large capi-
tulum attached laterally to the base of the
fifth joint, and directed* backwards.

The use of the antennae is that of hearing
or feeling the vibrations of the atmosphere,
and of smell. B. Hicks has pointed out the
existence in numerous insects of minute cavi-
ties or pits in the surface of the antennae,
furnished with a nerve-branch at the base,
to which these functions are attributable.
Hicks recommends the use of an aqueous
solution of chlorate of potash, acidified with
muriatic acid, for bleaching the chitine, and
rendering these organs distinguishable.

An additional function in many insects
is that of common feeling or touch.

G. Hauser describes also a terminal sen-
sory organ in the antennae, composed of
bacillar cells, connected with a largish
nerve.

BIBL. Kirby and Spence, Entomol. ; Bur-
meister's Man. fyc., transl. by Shuckard ;
Newport, Art. Insects, To&tfs Cycl. An. #c.
ii. ; Westwood's Introd. fyc. ; Hicks, Linn.
Tr. 1859, xxii. pp. 147 & 323 ; Claparede,
Ann. d. Sc. Nat. Zool. 1858, x. p. 236; Hauser,
Zeit. wiss. Zool 1880, xxxiv. p. 367 (Jn. Mic.
Soc. 1881, i. p. 33).

ANTENN ATRIA, Link.— A supposed
genus of Antennariei (Phycomycetous
Fungi), referred by Fries to Perisporiaceae,
and probably often consisting of forms of a
Mucedinous state of CAPNODIUM. They
are byssoid products growing upon dead or
living structures, or sometimes in cellars.
A. (Racodiuni) wllaris is the fungus of wine-
cellars, and is placed by Fries in the genus
Zasmidium.

ANTENNARIEI.

ANTHER.

Fig. 22 a.

Antennaria laevigata. Highly magnified.

BIBL. Corda, Icones, i. pi. 6. fig. 289;
Berkeley, Crypt. Bot. p. 275 ; Cooke, Hand-
book, p! 628.

ANTENNARIE'I.— A supposed family
of Phycomycetous Fungi, consisting of dif-
fuse plants, forming nocculent or byssoid
patches upon leaves or bark, which appear
to be merely states of other genera ; the
epiphytic Antennaria are referred to Capno-
dium, which, like Zasmidium (Antenn. cel-
laris), is a Perisporiacea. Two other genera,
Pleuropyris and Pisomyxa, were described
by Corda, but little is known respecting
them.

BIBL. Fries, Summa Veg. Scan. p. 406 ;
Berkeley, Crypt. Sot. p. 296.

ANTENN'ULA'RIA, Lamk.— A genus
of Hydroid Zoophytes, family Plumula-
riidae.

Distinguished by the whorled, hair-like
branchlets, and uniserial cells. Two British
species : —

A. antennina. Main stalks simple, clus-
tered, branchlets short. On sandy soils and
stones lying in sand ; deep water.

A. ramosa. Main stalks branched. On
old shells and stones from deep water.

BIBL. Johnston, Brit. Zooph. 85 j Gosse,
Mar. Zool. i. 24 ; Hincks, Brit. Zooph.
p. 279.

ANTHER.— The essential part of the
male or fertilizing organ of Flowering
Plans, supported on a longer or shorter stalk
or filament, and constituting with it the
stamen. The microscopic examination of
anthers turns in two distinct, both very in-
teresting directions, namely, study of the
development and characters of the pollen
produced in the anthers, and examination
of the cellular structure of the walls of
the perfect anther. For the former, see
POLLEN.

The cells of the anthers of almost all
plants exhibit deposits of a more or less
fibrous character, varying- much in the pat-
terns according to which the fibres are

placed, and the extent to which they are
developed ; and these are elegant micro-
scopic objects.

The anther is clothed with a very delicate
epidermis, sometimes provided with sto-
mata ; this epidermis usually remains un-
altered, but in some cases (Lupinm) the
walls acquire fibrous thickening. Beneath
this epidermis ordinarily lie one or more
layers of cells which form the spiral-fibruus
tissue. This may extend all round the
anther, or be wanting at certain points,
especially over the connective, before and
behind ; sometimes all the cellular tissue of
the connective itself assumes the same cha-
racter (with the exception of its vascular
bundle).

Purkinje has furnished a most extensive
notice of the conditions of these fibrous cells
in the different families of Flowering Plants.
The following plants are selected as afford-
ing considerable diversity of forms : —

a. Spiral fibres. Narcissus poeticus, Po-
pulus alba, Lonicera tartarica, Hyoscyamus
orientalis, Datura Stramonium. Cheiranthus
Cheiri (PI. 40. fig. 1).

b. Annular fibres. Iris florentina, Hya-
cinthus orientalis, Bunias orientalis, Chei-
ranthus Cheiri, Convallaria.

c. Reticulated fibres. Fritillaria imperi-
alis (on the internal face), Tu'lipa Gesneriana
and Viola odorata (ditto), Saxifraga um-
brosa (PI. 40. fig. 2).

d. Fibres arched (found on three sides of
the walls, the fourth being free). Nuphar
lutea, Bryonia dioica, Cynoglossum, Pulmo-
naria, Primula sinensis, Passiflora ccerulea,
Ligustrum vulyare, Cucurbita, Pyrus, Lupi-
nus (PI. 40. fig. 3).

e. Fibres short and straight, pieces upon
the walls standing vertically to the epider-
mis. Arum, Calla cethiopica, Calceolaria,
Delphinium, Anemone.

f. Like d, but converging towards the
centre of the upper wall of the cell, some-
times forming a star. Corydalis lutea, Im-
patiens, Fumaria, Cactus (PI. 40. fig. 4),
Polygonum, Tropceolum mqjus, Veronica per-
foliata, Polygala Chamceluxus, JRubia tinc-
torum, Armeria.

g. Fibres vertical, very short, numerous
and close, like teeth on the walls. Grasses,
Casuarina, Myosotis, Phlomis fruticosa,
Robinia, Adonis vernalis, Glaucium luteum,
Chelidonium majus, Magnolia, Liriodendron,
Dahlia, Leontoaon, Solidago, Bettis perennis
(PI. 40. fig. 5), Geranium, Pelargonium,
Pinus, Citpressus, Junipems.

ANTHERIDIA.

ANTHINA.

h. The walls simply thickened like wood-
cells. Zamia.

Other intermediate modifications exist;
and it is necessary to observe that the cha-
racter of the markings often differs in dif-
ferent parts of the wall of the anther. The
side of the cell-wall next the cavity is that
generally most marked ; the outer wall lying
next under the epidermis is often smooth
and unmarked.

A similar structure is found on the walls
of the sporanges of many of the Hepaticae,
such as Marchantia (PL 40. fig. 35), Junger-
mannia, &c. (see HEPATIC^). Also on the
walls of the sporanges of Equisetum (see
EQUISETACE^J). For further particulars
respecting the relations of these cells to
other spiral-fibrous tissues, see SPIRAL
STRUCTURES.

BIBL. Purkinje, De cell, anther. Jibrosis,
Wratislaviffi, 1880 5 Sachs, £ot. 1874,
525.

ANTHERIDTA.— The general name ap-
plied to all the various structures in which,
certainly or probably, the fertilizing function
of reproduction resides in Flowerless Plants,
and which consequently "correspond physio-
logically to the anthers of the Flowering
Plants. " They differ to some extent in the
character of the final products, which are
extremely minute bodies, some exhibiting
spontaneous motion when placed in water.

The antheridia of the higher Flowerless
Plants, those with leaf and stem, produce
active filaments, coiled more or less in a
spiral form, and the motion is here connected
with the presence of cilia upon the spiral fila-
ments. With regard to those of the Thallo-
phytes, the antheridia are not everywhere
so well understood. Their existence is
clearly ascertained in the Fucaceae, and the
active bodies are ciliated. The function of
the so-called antheridia of the Florldeae is
not yet proved, and it is denied by Thuret
that the antherozoids (or spermatozoids)
have a power of motion ; recent researches
among the Confervaceae have shown the
existence of antheridial cells, producing
active spermatozoids, to be very general in
that order. In the Fungi and Lichens the
antheridia seem to be represented by a dif-
ferent kind of structure, which produces
minute stick-shaped bodies, apparently not
endowed with spontaneous motion.

The moving oodies from the antheridia
are called spermatozoids, antherozoids, or
spermatic filaments in the higher Crypto-
gamia. The active bodies of the Fungi

Fig. 23.

and Lichens have been provisionally named
spermatin.

The antheridia of the Marsileaceae are re-
presented by the smaller form of spore pro-
duced in the sporanges (see MARSILEACEJE).
This is also the case in regard to the Lyco-
podiaceae so far as Selayinella and Isoetes
are concerned (see LYCOPODIACEJE). In the
Ferns and Equisetaceae the antheridia are
produced along with the
archegonia on the prothal-
liuni or cellular frond re-
sulting from the germina-
tion of the spore (see
FERNS and EQUISETA-
CEAE) . In the Mosses and
leafy Liverworts, the an-
theridia are produced in
terminal or axillary buds,
associated with or sepa-
rate from the archegonia
(fig. 23). In the fron-
dose Liverworts, they are

imbedded in the frond, Bartramia fontana.
Or more Or less raised Male inflorescence
from it on special recep- with antheridia and
tacles (see MOSSES and nifiecl ^diameterf."

HEPATICJE).

The antheridia are represented in the
Characeae by the so-called globule, in which
are produced filamentous spermatozoids re-
sembling those of Mosses (see CHAR A).

Antheridia occur in Saprolegniae (Pringsh.
Jahrb. Bd. vi. p. 249 &c. ; Tab. Fungi, fig.
26), and have been observed in Tuber and
Peziza. (See Pringsh. Jahrb. Bd. ii. p. 378
&c. ; De Bary, Ann. d. Sc. Nat. Juin 1866.
p. 343; Tulasne, ibid. De'c. 1866, p. 211.)

The supposed antheridial organs of the
Lichens are called spermogonia, and will be
found described under LICHENS; and the
analogous structures found in certain Fungi
called by the same name, are described
under CONIOMYCETOUS FUNGI, also under
the heads of certain genera of that family.
The antheridia of the Algae are described
under Fucus, FLORIDE.S:, (EDOGONIUM,
VAUCHERIA, SPH^EROPLEA, VOLVOX.

ANTHEROZOIDS.— The term applied
by the French authors to SPERMATOZOIDS.

ANTH'INA, Fries.— A genus of Isariacei
(Hyphomycetous Fungi), composed of mi-
nute fibrous plants, often of bright colours,
growing upon dead leaves &c. in autumn.
One British species is recorded : —

A.Jlammea,Yr. Attenuated downwards,
smooth, crimson-saffron, dilated upwards,
feathery, yellow. Clavaria miniata, Purton.

ANTHOCEROS.

ANTHOPHORA.

Fig. 24.

A beautifully coloured Fungus, varying as
to the degree of ramification, scarcely 1-2 "
thick at the base ; thickened upwards, as also
are the branches ; fibrous and feathery at
the summit ; solitary ; from 1-2" to 1" high ;
turning blackish when dried. The spores
separate very readily when the specimens
are placed in water for examination.

It may, however, be doubted whether
even Anthinajlammea, which occurs occa-
sionally in considerable quantity* amongst
dead leaves in shady woods, is an autono-
mous fungus, though it may be difficult to
point out of what species it may be a state,
unless it be related to Thelephora tnultizo-
nata, Berk.

BIBL. Purton, iii. 1. 18 ; Nees and Henry,
Syst. d. Prize, 1837, t. 6; Fries, Summa
Vecjet. p. 465.

ANTHO'CEROS, Mich.— A genus of
Anthoceroteae (Hepaticse).

The forms found in Britain
are regarded by Hooker as
varieties of one species. By
the continental botanists they
are divided into two: A.punc-
tatus, with the frond dotted
and divided at the margin ;
and A. lavis, with the frond
smooth (fig. 24).

These plants are found in
very moist situations, at the
sides of ditches <fcc., fruiting
in spring. The ovate-oblong
fronds are from \ to f of an
inch long, lying fiat, and
often forming round patches,
overlapping one another, ra-
diating from a centre and
more or less divided at the
margin. The texture is be-
tween membranaceous and fleshy, inclining
to the latter; the colour deep green, lighter
at the margins. The antheridia and arche-
gonia are usually abundant on the same in-
dividual. The antheridia are spherical, with
short stalks, of a yellowish-orange colour,
included in cup-shaped, deeply toothed re-
ceptacles on the upper face of the fronds.
The young archegonia differ from those of
any other Hepaticse in their structure, since,
instead of free, flask-like cases, they are
tubular cavities running down from the
upper face of the frond, with an embryonal
cell at the bottom, which increases by de-
grees into a conical body, and finally emerges
on the surface, surrounded by a perichsete
continuous with the epidermis of the frond.

Anthocer09 lffivia.
Magnified 2 dia-
meters.

The conical body by degrees grows up into
the narrow pod-like sporange, which attains
a length of about 2 inches, and is supported
on a short pedicel, 2 to 3 lines high, almost
concealed in the perichsete. The sporange
splits down the middle into two valves,
which become slightly twisted, and leave
in the centre a thread-like column, to which
adhere for a time many of the spores and
elaters. The spores, — the development of
which has been a subject of much study, and
is very instructive, — from the long sporange
containing specimens of successively older
formation from one extremity to the other,
— are of the ordinary character of these
tribes, having a reticulated outer coat,
marked by ridges indicating the mutual pres-
sure of the four spores formed in each parent-
cell. The elaters are much simpler than
usual, consisting merely of membranous
tubes, not very long, but sometimes irregu-
larly curved or branched, without any spiral
fibre in their interior. Gemmae also occur
on the frond ofAnthoceros.

BIBL. Dev. of the Fruit generally : Hof-
meister, Hohern. Kryptoyamen, Leipsic,
1851 ; Schacht, Entw. d. Prucht und Spore
v. Anthoceros lecvis, Bot. Zeif. 1850. Spores :
Mohl, Linncea, 1839 ; Vermischte Sc-hriff.,
Tubingen, 1846 ; Nageli, Veget. Cells (Itny
Society}, 1846, p. 229; Carrington, Brit.
Hep., 1881 ; Sachs, Bot. 351.

ANTHOCEROTEyE.— A tribe of Liver-
worts or Hepaticae (which see), containing
one British genus, ANTHOCEROS.

ANTHO'PHORA, Latr.— A genus of
Insects, of the order Hymenoptera, and
family Apidae.

Char. Wings with three complete sub-
marginal cells of equal size ; labial palpi with
the third joint affixed obliquely; maxillary
palpi 6-jointed ; intermediate legs of male
with long brushes of hair.

There are two species, A. retusa and A.
Haivorthana.

A. retusa (mason bee) is commonly seen
flying about sunny and sandy banks from
March to the beginning of June. Its head
and trophi are represented in PI. 33. fig. 24.

The antennce (a) are inserted in the centre
of the face, not approximating, short, geni-
culated, and 13-jointed in the male ; basal
joint (scapus) very pubescent, second (pedi-
cella) globose, third as long as the first,
fourth shorter than any of the following,
which are oblong; they are similar in the
female, but a little longer, and 12-jointed.
Ldbntm (e) deflexed, convex, with two black

ANTHOPHYSA.

ANTLIA.

spots at the base, anterior margin a little
convex and ciliated. Mandibles (f) slightly
curved, clothed with long hairs, notched
near the apex ; larger in the females, and but
slightly notched below the apex. Maxillce
((/) with the basal portion short and broad,
hairy, the edge above pectinated, terminal
lobe* long and lanceolate, with a small pencil
of hairs at the apex. Palpi (h) rather long
and setaceous, 6-joiuted, basal joint short,
second long, the" remainder decreasing in
length. Mentum rather short and linear.
Tongue (*) very long and slender, ringed and
tubular, the interior margins very pilose,
terminated by a lanceolate appendage. Pa-
raglossce (of) lanceolate. Palpi (&) extend-
ing as far as the tongue, slender, tapering,
4-jointed, basal joint very long, second not
half the length, ciliated towards the apex,
third inserted below the apex, and very
small, as well as the fourth. Head sub-
trigonate ; eyes (c) long and narrow ; ocelli
(b) three. TThorax much broader than the
head in the female. Legs rather robust ;
tibiae, posterior dilated and very pilose ex-
ternally, and the intermediate ones also in
the females ; tarsi, intermediate pair long in
the males, the basal joint of the 4 posterior
dilated in both sexes, and furnished with a
strong brush at the apex in the hinder pair
of the female. Claws bifid in the males,
with a tooth on the underside in the female.
Pulvilli distinct. Male thickly and minutely
punctured, and clothed with fulvous or yel-
lowish hairs, more or less black at the apex
of the abdomen ; female black, very pilose.
See INSECTS.

BIBL. Curtis, Brit. Entomol. viii. p. 357 ;
West-wood, Introd. &c. ii. p. 277.

AKTHOPHY'SA, Duj.— A genus of In-
fusoria, of the family Monadina, Duj. ; Fla-
gellata, Kent.

Char. Bodies ovoid or pyriform, with a
single anterior flagelliform filament (two,
one shorter than the other, Kent), and ag-
gregated at the ends of the branches of a sup-
port or polypidom, which is secreted by them.
The groups, when free, resemble Urella,
and revolve in the liquid containing them.

The branched support is of an irregular
arborescent form, at first soft and glutinous,
afterwards becoming brownish, horny, and
nodular in appearance. According to Cohn,
the brownish filaments so frequently found
in decomposing pond- &c. water, are the
stalks of Anthophysa, and form Kiitzing's
genus Stereonema.

A. Mi'dleri (vegetans) (PL 30. fig. ]3).

Body thicker in front j length of stalks 1-250
to 1-120", length of single animal 1-2000",
Fig. 13 b represents a detached animal with
the larger flagelliform filament. This is the
Epistylis vegetans of Ehrenberg. The de-
tached groups of bodies form a species of
Uvettttj Ehr. ( Uvella uva ?). Fresh water,
common.

A. socialis. Bodies about 8 in a group.
On Conferva.

BIBL. Dujardin, In/us. ; Ehr. Inf.] Cohn,
Nova Acta, 1854, p. 109; Ann. N. Hist.
1866, xviii. p. 429; Kent, Inf. p. 266.

ANTHOSO'MA, Leach. — A genus of
Crustacea, of the order Siphonostoma, and
family Ergasilina.

Found upon the gill-covers and gills of
sharks.

BIBL. Baird, Brit. Entom. j Desmarest,
Cons, gener. sur I. Crustac.

ANTIGRAM'MA, PresL— A genus of
Scolopendrieae (Polypodiaceous Ferns). Ex-
otic.

ANTIMONIATE of soda.— The produc-
tion of this salt by the addition of antirno-
niate of potash to a neutral or alkaline solu-
tion of a salt of soda, is used as a test of the
presence of soda. The crystals are repre-
sented in PL 10. fig. 21.

BIBL. See CHEMISTRY.

ANTIMONY. See ARSENIC.

ANTITRICHTA, Br. and Sch.=NEC-

KERA.

ANT'LIA. — The spiral tongue or probos-
cis of the Lepidoptera.

This well-known beautiful organ (PL 33.
fig. 28), when extended, forms a long sucto-
rial tube, and when coiled up represents a
flat spiral, like the spring of a watch. It
consists mainly of two modified maxillae
(see INSECTS). According to Newport,
each maxilla is composed of an immense
number of short transverse muscular rings ;
these are convex externally and concave
internally, and the two connected organs
form a tube. Within each there are one or
more large tracheae (fig. 28c*J) connected
with the tracheae in the head. The inner
or concave surface which forms the tube
(fig. 28 cf) is lined with a very smooth
membrane, and extends along the anterior
margin throughout the whole length of the
organ. At its commencement at the apex
(fig. 28/*), it occupies nearly the whole
breadth of the organ, ard is smaller than at
its termination near the mouth, where the
concavity or groove does not occupy more
than about l-3rd of the breadth. In some

ANTROPHYUM.

ANYSTIS.

species, the extremity of each maxilla is
furnished along its anterior and lateral
margin with a great number of minute
papillae. These, in Vanessa Atalanta (the
red admiral butterfly) for instance, form
little barrel-shaped bodies (fig. 286, #,/)>
furnished at the free end with three or more
marginal teeth, and a larger pointed body in
their centre. There are seventy-four of
these in each maxilla, or half the proboscis.
Newport regards them as probably organs
of taste. There are also some curious ap-
pendages arranged along the inner anterior
margin of each maxilla, in the form of
minute hooks, which, when the proboscis
is extended, serve to unite the two halves
together, by the points of the hooks in one
half being inserted into little depressions
between the teeth of the opposite side ;
sometimes these are furnished with a tooth
below the apex (fig. 28 <?) .

This description of the structure of this
interesting organ does not appear to be
correct. We believe that the older view,
regarding each half of the Antlia as con-
taining a distinct canal, to be true, and
that the transverse rings, in fact the entire
frame-work of the organ, consists of chitine.
But the subject requires further investiga-
tion. The only muscular structure we have
detected in the organ, consists of bundles of
muscular fibres taking an oblique longitu-
dinal direction.

BIBL. Newport, Todd's Cycl. of An. and
Phijs. ii. p. 901 ; Hicks, Linn. Tr. 1860,
xviv. p. 148. See also INSECTS.

ANTRO'PHYUM,
Kaulf. — A genus of
PolypodiaceousFerns,
fain. Grammitideae.

Char. Sori carried
along the veins, im-
perfectly reticulated,
superficial or immers-
ed in a groove.

Fronds simple, of
firm fleshy texture,
with uniform hexago-
nal areolse. 16 species;

exotic. Antrophyumplantagineum.

BlBL. Hooker, Sp. Partofasorus. Magnified.

Fil p. 392.

ANUR^E'A, Ehr.— A genus of Rotatoria,
of the family Brachionaea.

Char. A single (red) eye-spot at the back
of the head, no foot or pediform tail.

In seven species the back of the carapace
is furnished with facets, in four with longi-

Fig. 25.

tudinal striae, in three it is smooth; in
thirteen it is furnished with teeth or spines
in front, in seven also behind. One species,
A. biremis, has two moveable spines on each
side.

Dujardin gives the following characters.
Carapace in the form of a depressed utricle
or sac, toothed in front and with a wide
orifice to allow of the protrusion of the rota-
tory organs, which are usually well developed
in the form of two rounded lobes, accom-
panied by setae or non-vibratile cilia in
several bundles ; no tail ; jaws digitate ; a
red eye-spot above the jaws; ova volumi-
nous, often adherent to the parent.

The species are both aquatic and marine,
and many of them are common in pure fresh
water; length from 1-240 to 1-10".

Ehrenberg describes 14 species j to which
Gosse adds 4.

A. curvicornis, E. (PL 43. fig. 5, viewed
from above ; fig. 6, side view).

BIBL. Ehr. In/us. ; Duj. In/us. ; Gosse.
Ann. N. H. 1851, viii. p. 202.

AN YS 'TIS, Heyd. (Erythraus, Duges;
Trombidium, Herm.). — A genus of Arach-
nida, of the order Acarina, and family
Trombidina.

Char. Palpi large, free, bi-unguiculate ;
mandibles unguiculate ; body entire ; legs
at their insertion contiguous, cursorial, i. e.
unguiculate, long, the last joint slender and
very long ; posterior legs tne longest.

A. parietinum. Colour vermilion ; legs
pale. Found between stones and in moss ;
and on book-shelves. Tromb. parietinum.
Herm. Mem. Apt. p. 37, pi. 1. f. 12.

A. ruricola. Body very minute, depressed,
nearly oval, slightly emarginate at the sides,
and broader behind than before; a few
hairs scattered over the surface ; eyes two,
black, placed at the anterior obtuse angles
of the body ; colour bright carmine, some-
times blackish in the middle, paler along
the back and in front ; legs and palpi colour-
less, except a bright red spot on each at a
little distance from the body. On stones
and on dry paths. (PI. 50. fig. 4, and PI. 2.
fig. 8.)

A. ftava. Yellow.

A. ignipes. Mottled with greyish brown
and yellowish red.

A. cursoria. Rose colour.
A. cornigera. Red with two blackish
lines down the back.

Actineda, Koch, is not generically dif-
ferent from Anystis (Murray).

BiBL. Hermann, Mem. ApteroL; Duges,

APATITE.

APHID^E.

Ann. d. Sc. Nat. 2 s^r. i. and ii. ; Koch,
Deutsch. Crust. &c. ; Heyden, Isis, p. 100 ;
Gervais, Walckenaer** Hist. d. Ins. iii. ;
Murray, Econ. Entom. p. 140.
APATITE, see ROCKS.
APHANIZOM'ENON, Morren (Limno-
chlide, Kiitzing). — A genus of Nostochaceae
(Confervoid Algse) forming a delicate bluish-
green mucous stratum on the surface of lakes
or standing water. The filaments are very
slender, flaccid and obscurely jointed. The
spermatic cells are much elongated, either
scattered or, more frequently, solitary near
the centre of the filament. Allinan inclines
to think they are formed by confluence of
adjacent cells; he found vesicular cells
(heterocysts) also, which Ralfs did not de-
scribe. This genus seems to form a con-
necting link between the Oscillatoriaceae
and Nostochaceee, as indicated by Hassall.
Ralfs enumerates three British species,
viz. — •

A. Flos-aqua, Linn. (PI. 8. fig. 1).— Fila-
ments about 1-3000" in diameter, cohering
laterally in flat lamellae which separate at
their extremities into fasciculi; spermatic
cells cylindrical, with an inconspicuous co-
vering.—Ralfs, An. N. Hist. 1850, v. pi. 9.
fig. 6 ; Limnochlide Flos-aqua, Kiitz. Tab.
Phyc. cent. i. pi. 91. fig. 2 a.

A. cyaneum, Ralfs. Filaments free, ag-
gregated into a thin mucous stratum ; spo-
rangia linear, 8 to 12 times longer than
broad, with a conspicuous hyaline covering.
—Ralfs, I c. pi. 9. fig. 7. Limnochlide Flos-
aqua, var. hercynicU) Kiitz. Tab. Phyc. c. i.
pi. 91. fig. 11 ?

A. incurvum, Morren. " Filaments arti-
culated, cohering together in flat laminae,
laciniated at the apex ; articulations 2 to 8
times longer than broad." Ralfs states that
the Irish specimens identified by Morren
do not agree with this character, being held
together by the mucous matrix rather than
cohering, as in Flos-aqua, and they are
neither fasciculated nor laciniated at the
ends. — Ralfs, /. c. pi. 9. fig. 8. Aph. incur-
vum, Thompson, An. N. H. 1850, v. 82 ;
Hassall, Alga, t. 76. fig. 6. Limnochlide
Flos-aqua, var. Harveyana, Kiitz. Tab.
Plnjc. c. i. pi. 91. fig. 2.

BIBL. Ralfs, Ann. N. Hist. 1850, v. 339;
Allman, Qu. Mic. Jn. iii. p. 21, and the
other works cited above.

APHANOCAP'SA, Na<*.— A genus of
Confervoid Algae ; consisting of spherical
green cells, imbedded in an amorphous ge-
latinous mass.

A. mrescens (PI. 3. fig. 2). On wet rocks
and stones. Other species.

BIBL. Rabenhorst, Fl. Aly. ii. p. 48.
APIIANOCH.ETE, Braun.— A genus
of Chaetophoreae (Confervoid Algse) allied
to Coleochate ; the bristles arising from the
backs of the cells are not sheathed, but
jointed in the upper part. Not yet detected
in Britain.

BIBL. Braun, Verjung. p. 196 (Ray Soc.
transl. 1853, p. 184) ; Rabenhorst, Alg, iii.
p. 390 (fig.).

APHANOTHE'CE, Nag.— A genus of
Confervoid Algse.

Char. Cells minute, rounded or oblong,
seruginous, enclosed in a gelatinous en-
velope.

A. microscopica (PL 3. fig. 3). In marshy
places, everywhere. Many other species.
BIBL. Rabenhorst, Aly. ii. p. 63.
APH'ID^E.— A family of Insects belong-
ing to the order Hemiptera (Hoinoptera,
Westwood). This family comprises the
insects known as plant-lice.

Rostrum more or less perpendicular or
inflexed, varying in length, being in some
species longer than the body, and consisting
of four joints (PI. 36. fig. 1). Labrum
long and pointed at the tip. Antennae of
moderate or of great length, setaceous or
filiform, and usually composed of 3-7 joints,
the last joint being sometimes obsolete and
the third longest (PI. 36. fig. 2). Ocelli
three to six in number, forming a large tri-
angle ; eyes compound, prominent, and semi-
globose. Thorax oval, with the prothorax
forming a transverse collar ; abdomen short
and convex, ovate or elongate-ovate, soft,
and generally furnished with a more or less
elongated tubercle or cornicle on each side
near the extremity. Wings, when present,
four; the anterior much larger than the
posterior, placed obliquely or nearly per-
pendicularly on the sides of the body in re-
pose ; the anterior with a strong subcostal
nerve, terminating near the apex in a broad
stigma, and giving off' two or three oblique
nerves running to the posterior margin of
the wing ; of these the one nearest the apex
is usually forked once or twice. These
variations in the arrangement of the post-
costal nerve form the distinguishing cha-
racters of the Tribes (Buckton). A papilla
with three bent hcoks on the costal margin
of the hind wings, works in a fold of the
posterior margin of the anterior wing, some-
what as in the Hymenoptera. Legs usually
very long and slender, with the thighs some-

APHID JE.

C

times thickened ; tarsi two-jointed. The
body is sometimes clothed with a mealy or
cottony secretion, secreted by roundish
warts which stand in rows upon the back ;
in some species this covering is so long that
the animal is entirely concealed by it, and
looks merely like a moving flock of wool.
It is sometimes employed by the females as
a covering for their eggs.

The Aphidae, like the rest of the order to
which they belong, are active in all their
stages ; the pupae being distinguishable from
the perfect insects only by their possessing
the rudiments of wings upon the back of
the thoracic segments. In the wingless
species this distinction of course does not
exist.

These insects reside, usually in large
societies, upon almost every species of
plant ; but the different species of plant-
lice, like the true lice of animals (Anoplura),
are generally restricted to one or two parti-
cular plants ; or when they are common to
a greater number of vegetable species, the
latter are usually very nearly allied. Each
species is also restricted to some particular
part of the plant ; but no part is exempted
from the attacks of particular species, which
are found upon the young shoots, the buds,
the leaves, the stem, even of trees, and the
roots. Of these parts they suck out the juices,
by placing the rostrum in a perpendicular
position, and forcing the included bristles
into the tissues of the plant ; the wound
thus formed is frequently enlarged by move-
ments of the body of the animal. In some
instances the irritation caused by these
wounds, inflicted by a colony of Aphides,
gives rise to a distorted state of leaves and
twigs, and even to gall-like excrescences, in
the interior of which the insects may be
found in great numbers.

The abdominal tubercles or tubes above
mentioned, which, however, are reduced to
simple openings in some species, are gene-
rally regarded as excretory organs, through
which a saccharine fluid is exuded. This
fluid is produced by many Aphides, especially
those which live upon trees and shrubs, in
great abundance ; it constitutes the well-
known honey-dew, which drops in large
quantities from some of our common trees
(particularly the Lime), and forms small
shining spots upon their leaves. The latter
were supposed by Liebig to be products of
a disease of the plants upon which they
occur. The sweet fluid is much liked by
ants and other Hymenopterous insects,

2 ] APIIID.E.

which seek the Aphides for the purpose of
sucking it from them, sometimes inducing
them to excrete it by stroking them with
their antennae, but sometimes biting and
tearing them to get at it. Kaltenbach con-
siders the abdominal tubes to be merely pro-
duced stigmata, and states that the saccha-
rine fluid is emitted through the anus; this
is also the opinion of De Geer, Kyber, and
others.

The propagation of the Aphides presents
some most remarkable peculiarities, and is
well worthy of a careful study . The ordinary
colonies of these insects, which may be met
with everywhere during the summer, consist
of winged and wingless individuals, the
latter being for the most part larvae and pupae.
The winged individuals are all viviparous and
capable of producing young larvae without
any intercourse with a male insect. During
the whole course of the summer, none but
these so-called viviparous females are to be
met with, and generation follows generation
without the appearance of a single male.
It is only in the autumn that males and true
females are produced as the last result of the
viviparous reproduction ; the latter are
usually apterous, even in the ordinarily
winged species ; and, after copulating, the
females lay eggs, which serve to continue
the race in the following summer. The
viviparous individuals of some species are,
however, said to live through the winter j
and the viviparous reproduction may be con-
tinued uninterruptedly for an indefinite
period by the maintenance of the necessary
conditions of temperature &c. ; at least
Kyber observed it for four consecutive
years in a colony kept in a room at a uni-
form temperature. The males are rarer,
mostly alate, and with a smaller abdomen.

The true nature of this wonderful mode
of propagation has been the subject of much
dispute, especially of late years. It will be
unnecessary for us to enter upon the con-
sideration of the various opinions that have
been put forward ; it is sufficient to mention
that it is now generally admitted to be an
example of the alternation of generations or
parthenogenesis, which occurs so frequently
amongst the lower animals, — the viviparous
forms being regarded as the products of a
sort of internal gemmation. According to
Huxley, the organs in which the young of
the viviparous forms are produced (pseitdo-
varia) are strictly homologous with the true
ovaries, and the germs of both forms are
identical, (the existence of the germinal spot

APHID^E.

[ 63 ]

APHRODITA.

in the pseudova is, however, denied) ; but
in the oviparous females, the germ is sur-
rounded by a vitellus and vitelline mem-
brane in the usual way to form a true egg ;
whilst in the viviparous individuals the
germinal vesicle itself enlarges and under-
goes a considerable change before acquiring
an investing membrane, within which the
embryo is gradually developed. Balbiani,
however, maintains that the viviparous
Aphides are really hermaphrodite.

From the nature of their production, it
will be easily understood that the fecundity
of the Aphides must be very great. The
most prolific species only live for about three
weeks, and in that time produce 30-40, or,
according to Reaumur, 90-100 young. In
these species there may be from 15-17
generations in the course of the summer ;
and Schrank, starting from Bonnet's obser-
vations, calculated the total theoretical pro-
geny of a single Aphis in the course of one
summer at 23,740,000. Their numbers are,
however, constantly kept in check by the
attacks of numerous enemies, amongst which
we may mention the common Lady-birds,
both in their larva and perfect states, the
larvae of the Dipterous genus Syrphus, and
of the Hemerobiidse, which prey upon them;
whilst many of the smaller Ichneurnonidae
and Chalcididae attack them for the purpose
of depositing eggs in their bodies.

Notwithstanding these checks upon their
production, the plant-lice increase suffi-
ciently to render them exceedingly injurious
to cultivated plants. The most noxious
species are the turnip-flv (Aphis Brassiccs,
PI. 36. fig. 3), the bean-fly (A. Papaveris),
which also occurs upon the poppy and
various other plants, and the hop-fly (A.
Humuli). The latter, when it abounds to
an unusual extent, causes the almost total
destruction of the crop of hops. One of the
most abundant species is the rose-fly (A.
Roses), which is often exceedingly injurious
to roses in gardens, by attacking the young
succulent shoots. Lachnus Quercus, a large
species with the rostrum three times the
length of the body, is found in the fissures
of the bark of old oaks ; the other species
of Lachmts live for the most part upon the
shoots and leaves of coniferous trees ; the
commonest is L. pinicola. Eriosoma lani-
gera (PL 53. fig. 3) is a common species
upon the stems of apple-trees, living in
societies in crevices of the bark, on which
it forms small, white, woolly patches. Te-
traneura Ulmi (PI. 30. fig. 4) lives in small

gall-like excrescences on the leaves of the
elm ; and the Pemphigus bursarius (PI. 36.
fig. 5), a woolly species, resides in similar
galls on the leaves and foot-stalks of the
poplar. Of the subterranean species, which
suck the roots of plants, the most abundant
is Trama radicis (PI. 36. fig. 6), which
occurs upon various composite plants, in-
cluding the common dandelion and the
garden-lettuce. Forda formicaria (PI. 36.
fig. 7) is the species commonly found in
ants' nests; it lives in small societies on
the roots of grasses, and is tended with
great care by the ants. Phylloxera vasta-
trix (PI. 53. fiV. 7) is the vine-pest.

The colouring-matter of the Aphides
partakes of the nature of chlorophyll
(Sorby).

BIBL. Westwood, Introd. fyc. ; Walck-
enaer, Hist. d. Ins. ; Kaltenbach, Monog. d.
Pfanzenlause, 1843 ; Koch, Aphiden, 1857
(tigs.) ; Burnett, Sillimarfs Jn. 1854, xvii.
pp. 62, 261; Walker, Ann. N. Hist. 2nd
ser. i. ii. iii. iv. &c. (1848-49) ; Claparede,
Ann. N. Hist. 1867, xix. p. 360 ; Balbiani,
ibid. 1866, xviii. pp. 62, 106 ; id. & Signoret,
ibid. 1867, xx. pp. 20, 149 ; Boisduval, En-
torn. Hort. p. 240 ; Huxley, Linn. Tr. xxii.
pp. 193, 221 ; Sorby, Tr. Mic. Soc. xi. p. 352 ;
Buckton, Aphides (Monoyr.}, Hay Soc.
1876.

APHRODITA, L.— A genus of Annu-
lata. One species of this genus (A. acideata)
is well known as the sea-mouse, and is
commonly found on the sea-coast, and
always admired on account of the splendid
iridescent colours reflected from its spines
and bristly hairs. Body from 3 to 5 inches
long, 1^ broad, and oval ; back of an earthy-
colour. Head small, entirely concealed!,
with two round clear spots, or eyes, on the
vertex. The hairs and bristles" run down
each side of the body ; the back is roughish,
with a thick felt of hair and membrane
forming a kind of skin. When this is cut
through, fifteen nearly circular plates or
scales (elytra) are found on each side,
which partly cover each other. If two of
the plates lying next each other be sepa-
rated, we then see upon the intermediate
ring small tubercles divided by a pit, fur-
nished behind with pectinate appendages,
the gills or branchiae.

Antennae minute ; palpi large, subulate,
jointed at the base. Mouth with a large
retractile edentulous proboscis ; the orifice
encircled with a short, even, thick-set fringe
of compound penicillate filaments divided

APHROSINA.

[ 64 ]

AP10CYSTIS.

into two sets by a fissure on each side.
Thirty-nine pairs of feet, biramous ; the
upper branch carries the long, flexible,
brilliantly coloured bristles forming the silky
fringe on each side of the body.

This animal is a very interesting object
to the microscopist, as its tissues are very
transparent and easily examined.

The brilliant colours of the bristles and
hairs arise from iridescence, produced by a
number of longitudinal striae or interspaces
between the component fibres of which the
bristles and hairs consist ; they also exhibit
transverse splits or cracks ; they are not
materially changed by the action of boiling
solution of potash, except that the external
coat of the hairs becomes transversely wrin-
kled, giving these the appearance of being
surrounded by a number of fibres (PI. 49.
fig. 20).

BIBL. Johnston, Ann. JV. Hist. 1839,
p. 430 ; Van d. Hoeven, Zool. p. 232.

APHROSI'NA, Carter.— A minute, pa-
rasitic, poriferous Foraminifer, with nume-
rous irregular, vesicular chambers. Allied
to Carpenteria.

BIBL. H. J. Carter, J. Micr. S. ii. 500.

APHTHA. — A disease affecting the mu-
cous membrane of the mouth, tongue, &c.
It exhibits itself in the form of rounded
patches of larger or smaller size, of a whitish
or yellowish colour. One form of it, vul-
garly called the " thrush," and in French
niuguet, which occurs very frequently in
children, and in adults towards the fatal
termination of chronic diseases, is of special
interest, inasmuch as the patches consist
of numerous epithelial scales mixed with
the filaments and isolated cells of a fungus
(Oidium albicans). A portion examined
under the microscope exhibits : — 1, nume-
rous oval cells (a, PI. 38. fig. 1), rarely con-
taining an internal globule or nucleus ; 2,
long filaments (6) exhibiting a further ad-
vanced stage of development ; the filaments
are but rarely jointed ; 3, epithelial scales,
sometimes perfect (d), but usually wrinkled
and otherwise altered in form, and fre-
quently more or less opaque (e), so as to be
hardly recognizable except when treated
with potash ; intermingled with these
bodies are sometimes vibriones or bacteria
(Bact. termo,f) and a molecular form of
matter (<?), probably an early stage of Bact.
termo ; for it is always found with and
prior to it in decomposing liquids, in addi-
tion to the molecular granules found in all
animal liquids.

This fungus appears to arise in the same
manner as other analogous fungi, as those
in kept organic liquids, in urine, &c. ; the
spores are probably always floating in the
air and dropping from it upon all the ex-
posed parts of the body ; and wherever they
find a proper nidus, there they grow. In
diseases accompanying or preceding aphtha,
the regeneration of the oral epithelium is
probably to a great extent checked, the
secretion of the saliva also, which would
wash away these organisms; why they
occur so frequently in infants, is probably
owing to the saccharine nature of the diet,
which is especially favourable to their de-
velopment.

It is to be observed of the numerous
parasitic Fungi which have been described
as preying on animal tissues, that a great
portion are mere conditions of common
species of Aspergillus, Penicillium, Mucor,
&c., which assume different forms according
to the nature of the matrix. This has not
been sufficiently kept in view by authors
unacquainted with the genera of Fungi ; and
in consequence, a great number of spurious
genera have been proposed, and considerable
confusion has ensued ; while the fashion of
late with Hallier and his followers has
been to confound things which are essen-
tially distinct. See OIDIUM.

BIBL. C. Robin, Hist. Nat. d. V6g. Para-
sites, 1853, p. 488, where many other works
are mentioned.

APIOCYSTIS, Nageli.— A genus of Pal-
mellaceae (Confervoid Algae). Aquatic plants
parasitical upon Confervae, consisting of
pear-shaped or clavate vesicles from 1-50"
to 1-20" high, and about half as thick, at-
tached by the narrow extremity, and con-
taining numerous green primordial cells
about 1 -2500 to 1-3500" in diameter. Young
sacs contain regularly 2, 4, 8, 16, 32, &c. ;
and in large ones the number amounts to
300 to 1600. At first they lie irregularly
in the cavity, afterwards they lie upon the
wall in one or more layers ; sometimes they
are attached to the wall in groups of eight.
At a certain stage, the primordial cells be-
come again free in the cavity, move actively,
and finally escape by the rupture of the sac,
swarm as biciliated zoospores for a time,
then settle down and germinate.

A. Brauniana (PI. 5. fig. 5) ; in ditches,
&c. Brit.

BIBL. Nageli, Einz. Ah/en, p. 67, t. 2. A.
figs. 1 and 2 ; Henfrey, fr. Mic. Soc. 1856,
iv. p. 49, pi. 4 j Rob. Alg. iii. p. 43.

APIS.

APUS.

A 'PIS, L. — A genus of Hymenopterous
Insects.

A. mellif'ica, the honey-bee, presents some
interesting points of structure.

The proboscis (PL 33. fig. 25) agrees
essentially with that of Anthophora. The
" tongue " (labium*) is a very beautiful and
favourite microscopic object; its minute
structure requires a higher power than that
used in making our sketch, to render distinct
the elegant transverse ridges or folds and
the terminal hairy lobe.

The legs are peculiarly formed for the
special purpose of collecting and carrying
the pollen of flowers. The tibiae of the
hind legs are dilated, smooth on the outside
in the neuter or working bees, and hollowed
into a shining plate (PI. 34. fig. 46), whilst
the basal joint of the tarsi is hooked at its
outer superior angle and dilated into an ob-
long or somewhat triangular plate (PL 34.
fig. 4a), which is furnished with transverse
rows of hairs, forming pollen-brushes.

BIBL. Westwood, Intr. &c. j Curtis, Brit.
Ent. 769.

APL AN ATISM.— Freedom from spheri-
cal aberration (in lenses).

APLIDIUM, Sav. — A genus of Mollusca,
of the order Tunicata, and family Botryl-
lidae.

The common mass is from 1 to 3 inches
high ; and the animal bodies about £-£ inch
long. Four British species : —

A. ficus, dark olive, orifices six-rayed ;
A. fallax, honey-yellow, with white and
brown specks, orifices circular ; A. nutans,
straw-yellow, tinted with brown, orifices
invisible ; and A. verrucosum, olive-green,
orifices entire.

BIBL. Forbes and Hanley, Brit. Mollusca,
i. 10.

APOTHECIUM.— The name applied to

Fig. 26.

Dirina Ceratoniae.

the female or spore-fruits of the Lichens.
Several special names have been applied to

the apothecia, namely, petta, scutetta, patella,
scyphus, orUculus, lirella, and verruca, indi-
cating the forms occurring in particular

Fig. 27.

Fig. 28.

Fig. 27. Apothecia, magnified. Fig. 28. Thecse and
paraphyses, from a vertical section of an apothecium,
magnified 200 diameters.

genera. They are shield-shaped, flat, cup-
shaped, globular, papilliform bodies, or linear
ridges, upon the upper surface of the thallus,
either immersed, superficial, or elevated on
peduncles. They contain the thecae or spore-
cases. For the structure, see LICHENS.

APPENDICULARIA, Cham.— A genus
of Mollusca, of the order Tunicata, and
family Salpidae.

1 British species : A.flagellina.

BIBL. Gosse, Mar. Zool. i. p. 37; Cha-
misso, Nova Ada Acad. Cur. x, ; Huxley,
Phil. Trans. 1851, p. 595.

APTOG'ONUM, Ralfs.— A genus of Des-
midiacese.

Char. Filament elongated, triangular or
flattened ; joints bicrenate at the free mar-
gins ; an oval foramen between the joints.

Kiitzing and others placed this organism
in the genus Desmidium, where it might
very well have remained.

A. Desmidium. Joints in front view
quadrangular, broader than long.

a. Filaments triangular, regularly twisted,
crenatures rounded ; length of joints 1-1500",
breadth 1-1000" (PI. 14. fig. 55, front view ;
fig. 52, side view).

(3. Filaments flattened ; crenatures shal-
lower and slightly angular.

A. Baileyi. Filaments not crenate ;
joints about equal in length and breadth.
American.

The latter cannot be retained in this
genus, unless the characters be altered, on
account of the absence of the crenatures

BIBL. Ralfs, Br. Desmid. pp. 63, 208.

A'PUS, Scop. — A genus of Entomos-
traca, of the order Phyllopoda, and family
Aspidephora,

ARACHNIDA.

C 66 ]

ARACHNID A.

Char. Head, body, and greater part of the
abdomen covered by a shield-like carapace,
which is deeply notched behind ; eyes two,
sessile and approximate ; a single pair of
minute, short, styliform and two-jointed
antennae ; legs, sixty pairs, the first pair
furnished with three long jointed branches,
extending beyond the carapace, the rest
branchial ; body composed of numerous
rings ; two long jointed caudal appendages.

A. cancriformis. Freshwater, in stagnant
pools ; brownish yellow; length 2^ inches.

A. productus. Not British ; an elongated
oval lamina between the two caudal appen-
dages.

BIBL. Baird, Brit. Entom. p. 18 ; R. Lan-
kester, Qu. Micr. Jn. 1881, xxi. p. 343.

ARACHNI'DA.— A class of animals con-
taining the spiders, scorpions, &c.

Char. Head united with the thorax,
forming a cephalothorax ; antennae none ;
eyes simple (ocelli) ; legs eight, jointed.

The integument of theArachnidais usually
soft and leathery, rarely horny or brittle, and
consists principally of chitine. Two layers
may usually be distinguished, an outermost
or cuticle, which is the firmest and strongest,
and not unfrequently exhibits a cellular ap-
pearance in the extremities and the cepna-
lothorax. The cuticle of the abdomen of
the Araneae, Acarina, £c. presents very
beautiful wavy or undulating lines, some-
times surrounding the roots of the hairs &c.
concentrically, and arising, in some cases at
least, from the existence of folds (PL 6. figs. 4
& 5). The cuticle of the Arachnida is fre-
quently covered with warty and bulbous
excrescences, bristles and simple or feathery
hairs, and sometimes with scales.

The innermost cutaneous layer consists of
a very delicate and almost colourless mem-
brane, of a finely granular or fibrous appear-
ance, close beneath which is situated a
layer of pigment granules and cells, which
are visible through the general integument,
and to which the beautiful colours of many
of the Arachnida are owing.

The organs surrounding the mouth vary
in structure in the different families. In the
Spiders, two mandibles are situated at the
front of the head. These consist of two
joints— a basal, very thick one (PL 6. fig. 6 a
& 7 a), and a terminal, curved and sharply
pointed one (fig. 66 & 7 b). The latter is
traversed by a canal terminating at its apex,
through which the secretion of a poison-
gland passes into any body transfixed by the
claw. These mandibles are perhaps, strictly,

modified antennae . Next come two maxillary
palpi (fig. 7 c), which do not differ in struc-
ture from the legs, except in their tarsi
being composed of a single joint, generally
terminated in the females by a small hook,
but in the males of more complicated struc-
ture : the basal joints of these palpi are
enlarged and project forward, forming the
maxillae (fig. 7 d) ; these are stated to con-
tain certain glands, opening on the inner
side of the upper face. In the scorpions,
the mandibles and maxillary palpi terminate
in pincers or forceps. Lastly a labium,
situated between the maxillae (fig. 7e), and
consisting of a single piece.

The mouth in the other families is de-
scribed under the respective heads.

The eyes are simple (ocelli, stemrnata),
but they are absent in the parasitic Acarina ;
they consist of a simple arched cornea, a
spherical lens and a concavo-convex vitreous
body, with a cup-shaped retina, and a layer
of pigment corresponding to the choroid.

The cephalothorax is usually separated
from the abdomen by a well-marked con-
striction ; but sometimes the head, thorax,
and abdomen are fused together.
.The legs of the Arachnida, which are
attached to the cephalothorax, do not co-
incide exactly with those of insects. They
usually consist of seven segments tapering
towards the end, so that the tarsi are less
distinct from the other parts than in insects.
If we suppose that the last two joints belong
to the tarsus, the tibia then consists of two
joints, of which, in some (the scorpion and
Phrynus) the first, in others the second, is
the longest. The preceding long j oint is the
femur, next to which comes an annular or
inverted conical joint, corresponding to the
trochanter of the six-footed insects. The
first, broad, usually inversely conical joint,
which is adherent to the cephalothorax, cor-
responds to the coxa of insects. The last
joint of the tarsus usually supports three
curved hooks or claws (Pl/6. fig. 8), which
are frequently toothed on the concave mar-
gin, and in some a membranous vesicular
or hairy cushion (pulvillus) on its under
side. The most characteristic feature of the
Arachnida consists in the division of the
tibia into two unequal pieces.

The first pair of legs is supposed to repre-
sent the labial palpi of insects.

The alimentary canal is mostly short and
straight, In the Araneae the oesophagus
enlarges into a prismatic muscular expan-
sion just before its termination in the sto-

ARACHNID A.

[ 67 ]

ARACHNIDA.

mach; the stomach splits just behind the
above apparatus into two branches, which
curve forwards and form a ring, from which
five pairs of diverticula pass to the roots of
the legs and palpi.

Salivary glands are present, consisting in
the Aranese of a transparent glandular mass
situated in a cavity above the palate ; also a
hepatic apparatus, in the form of a compact
mass, consisting of a number of ramified and
closely-crowded casca, containing the hepatic
cells and opening at about the middle of the
alimentary canal in four short ducts. This
hepatic apparatus was formerly mistaken for
the fat-body. In the Tardigrada, Acarina,
and some others the liver is represented by
the granule-cells, usually brownish yellow,
of the walls of the diverticula of the stomach.

The poison-glands of the Araneae consist
of two long, sometimes slightly curved blind
sacs, the walls of which are surrounded by
a simple spiral layer of muscular fibres.

Circulatory System. — In the lower Arach-
nida, as the Tardigrada, Acarina, &c., there
is neither dorsal vessel nor blood-vessels.
Hence in these there is no regular circulation
of blood, but the nutritive fluid or the blood
is distributed free in the interstices of the
body, and is irregularly moved backwards
and forwards, propelled in the cavity of the
body, and into the extremities, by muscular
movements and the contractions of the in-
testinal canal.

In the Araneae there is a dorsal vessel
consisting of a spindle-shaped tube lying
principally in the abdomen, constricted at
intervals and furnished with lateral apertures
and valves. This heart sends off lateral and
terminal arterial branches, which gradually
become lost. There are no veins ; but the
further course of the blood takes the form
of lacunal currents, which re-enter the heart
at the valvular orifices.

In the scorpions, there are veins as well
as arteries.

Respiratory System, — In the Tardigrada
and some parasitic Arachnida, Demodex,
Sarcoptes, Acarus, &c., no tracheae or other
respiratory organs have yet been discovered ;
hence the respiration must be cutaneous. The
higher Arachnida breathe either by tracheae
(many Acarina), or by lungs, or by both.

The tracheae of the Acarina are remarkably
delicate, so that the spiral fibre is with great
difficulty distinguishable. They arise usually
in an uuramified bundle from two stigmata,
which are sometimes situated anteriorly, be-
tween the front legs, as in the Hydrachnea,

and much concealed, at others at the sides
of the body above the third pair of feet, as
in the Gamaseae, or behind the last pair, as
in the Ixodeae. They are usually more
tufted than branched as in insects.

In the Hydrachnea, which live in the wa-
ter, and do not rise to the surface to respire,
the tracheae must possess the power of ab-
sorbing the air from the water. In the
Araneae, the lungs consist of rounded sacs
situated at the anterior part of the under
surface of the abdomen, and open externally
by a transverse slit. At the outer convex
surface of each lung-sac there are a number
of thin but firm triangular or rhomboidal
plates, like the leaves of a book, closed to-
gether (PL 6. fig. 9). When examined by
reflected light, they present a silvery lustre ;
whilst by transmitted light they appear dark
violet or almost black. Each of these plates
consists of a fold of the skin, between which
the air of the sac is widely distributed : they
contain on blood-vessels; hence probably the
blood brought by the arteries is poured out
around the lungs, and so bathes the lung-
plates. The position of the lung-sacs is in-
dicated externally by a triangular and horny
cutaneous plate, at the posterior margin of
which the respiratory fissure exists. Behind
these fissures there are two other openings,
the orifices of a tracheary system which
does not differ materially from that of such
as have tracheae only.

Nervous System. — Varies in degree of
complexity. In its simplest form it exists
as a single oesophageal ganglion, sending off
radiating branches ; and in its most compound
forms it presents a large cephalothoracic
bilobed ganglion, and one or two ventral
ganglial chains or cords.

The primitive nervous fibres and gan-
glion-cells are very small and delicate.

Spinning-organs. — These organs, by means
of which the Araneida form their webs, are
of great interest. The external organs con-
sist of three or rarely two pairs of cones or
conical papillae, or spinnerets, placed at the
end of the abdomen, below the anus : they
are somewhat flattened at the summit; and
usually the middle pair consist of two joints,
and the anterior and posterior pairs of three
joints. The sides of the cones are covered
with hairs; and on the summits are a number
of delicate horny spinning-tubes, at first sight
closely resembling hairs ; these form con-
tinuations of the spinning-vessels. Some-
times, however, the lower portions of the sides
of the cones are furnished with spinning-

ABACHNIDA.

ABACHNIDA.

tubes, the remainder being covered with
hairs. Each spinning-tube consists of two
parts : — a thicker basal portion ; and a thin
terminal portion, from the orifice of which
the substance of the fibre exudes (PL 6. fig.
10, 10 a, separate tubes). The number of
these spinning-tubes varies according to the
species, the sex, and the age of the spiders.
In some there are more than 1000, in others
400, 300, 100, &c., and in others still fewer.
The glands which secrete the tenacious
transparent secretion are very variable in
number, form, and arrangement, and occupy
the interstices of the other abdominal vis-
cera, consist of sacs and tubes, lined with nu-
cleated cells, and either simple or variously
ramified, terminating in ducts which open
at the roots of the spinning-tubes.

The filaments of which the webs of many
spiders are composed are not all alike. The
radiating filaments are but little elastic, and
are composed simply of one or more threads ;
whilst the more numerous (tangential) fila-
ments connecting these are covered at tole-
rably regular intervals with minute spherical
masses of glutinous matter (PI. 6. fig. 11),
the filaments themselves being highly elas-
tic. These masses give the fibres an elegant
beaded appearance under low powers of the
microscope. The viscid masses cause the
more ready adhesion of the filaments to in-
sects which may accidentally become en-
tangled in them, and render the spider more
sure of holding his prey.

Propagation. — The Arachnida generally
are propagated by sexes. The sexual appara-
tus consists of two ovarian or seminal sacs,
sometimes fused together in the middle line ;
they are situated in the abdomen, and termi-
nate in two excretory ducts, which usually
open at a common orifice placed at the base
of the abdomen, or below the cephalothorax.
A penis is not generally present ; the seminal
fluid is applied to the vulva of the female
by the maxillary palpi of the male.
Parthenogenesis has been observed in
Acarina.

Spiders are oviparous ; the eggs are en-
veloped in a cocoon, and are often elegantly
sculptured.

There is no metamorphosis, but repeated
ecdysis.

The Arachnida may be thus subdivided : —
Order 1. ABANEIDA. Cephalothorax con-
stricted from the unjointed abdomen ;
palpi unarmed.

Order 2. PEDIPALPI (Phrvnida). Cepha-
lothorax distinct from the jointed abdo-

men ; palpi large, leg- like, chelate at the
end. (Pulmonary sacs present.)
Order 3. SOLIFTJGJE (Solpugida). Cepha-
lothorax distinct from the jointed abdo-
men ; palpi filiform, extended, as long as
the legs, unarmed.

Order 4. PSEUDOSCORPIONES (Obisida) ;
Book-scorpions. Cephalothorax distinct
from the ringed abdomen; palpi large,
chelate. (Tracheae only present.)
Order 5. PHALANGITA (Opilionina) ; Har-
vest-spiders. Cephalothorax distinct from
the annulate or transversely plicate abdo-
men ; palpi simple, filiform ; mandibles
chelate ; legs very long, terminated by a
single claw.

Order 0. ACARINA (Mites). Head, thorax,
and abdomen fused together ; legs di-
stinctly jointed ; palpi simple.

Fam. 1. Acarea. Head terminated in
front by an emarginate labrum, or single
bifid process ; palpi adnate or adherent to
the labium, difficultly distinguished ;
mandibles chelate ; no distinct ocelli ;
legs generally terminated by a vesicle or
adhesive acetabulum and claws.

Fam. 2. Oribatea (Beetle-mites). Body
covered by a hard horny envelope ; man-
dibles chelate; palpi fusiform, 6-jointed;
legs furnished with claws, but no vesicle
or acetabulum.

Most of the species live in mosses at
the roots of trees ; in some the body is sur-
rounded bya projectinglamella on each side.

Fam. 3. Ixodea (Ticks). Palpi canali-
culate, sheathing the rostrum ; mandibles
three-jointed, basal joint internal, second
joint external and long, third short and
denticulate ; labium covered withreflexed
teeth. (Parasitic.)

Fam. 4. Gamasea (Insect-mites).
Palpi free, filiform ; mandibles chelate ;
feet with two claws and a caruncle, or a
lobed membranous appendage; ocelli none
or indistinct. (Generally parasitic.)

Fam. 5. Hydrachnea (Water-mites).
Palpi with the last joint unguiculate or
spinous ; two or four distinct ocelli ; coxae
broad, legs generally ciliated, natatory,
the posterior longest. (Aquatic.)

Fam. 6. Bdellea (Snouted mites). Palpi
antenniform ; mandibles terminating in
claws or pincers ; rostrum resembling an
elongated head; body generally divided
between the second and third pairs of legs
by a transverse furrow or stricture.

The species are minute, more or less
soft, variously coloured, and living in

ARACHXIDA,

[ 69 ] ARACHNOID MEMBRANE.

damp places beneath moss, upon sand of
caves, &c.

Fam. 7. Trombidina (Harvest-mites).
Palpi with the last joint obtuse, the
second joint very large; the last but
one (penultimate) resembling an incur-
vated claw ; feet cursorial, terminated by
two claws.

Fam. 8. Hypoderidge (Subcutaneous
mites). Oval-oblong, almost transparent
sacs ; the anterior and posterior pairs of
legs widely apart ; tai si terminated by two
fine hairs.

The species are found in the subcu-
taneous tissue of birds.

Fam. 9. Phytoptidae (Gall-mites).
Legs foui', the hinder pairs replaced by
tubercles or hairs.

In the galls and buds of plants.
Order 7. TARDIGBADA (Colopoda) ; Water-
bears. Legs rudimentary, very short,
conical, indistinctly three-jointed, and
with three or four claws ; abdomen not
distinct from the thorax. (Aquatic.)
Order 8. PYCNOGONIDA (Polygonopoda) ;
Crab-spiders. Cephalothorax forming a
4-jointed body ; abdomen rudimentary
(small and conical) ; legs as long as or
longer than the body.

Sluggish marine animals, living under
stones, upon marine plants, or parasitic
upon fish and Crustacea.
BIBL. Treviranus, Ban der Arachn. ;
id. Vermischte Schrift. $c. Bd. 1, 1816;
Dufour, An. d. So. physiq. d. Brux., iv.-vi. ;
Walckenaer, Hist. nat. d. Ins. Apt., i.-iii. j
Siebold & Stannius, Lehrb. d. vergl. An. i. ;
Blackwall, Brit. Spiders (Ray Soc.) 1861-4,
and Linn. Tr. xvi. ; Blanchard, Ann. N. Jf.
1850, vi. 67 ; and 1852, x. 150 ; Newport,
Phil. Tr. 1843 ; Koch, Uebersicht fyc., and
Arachnid. (534 pis.) ; Claparede, IS tool. $c.
1863 ; id. Circulation, $c., Ann. N. H. 1865,
xv. p. 16; Cambridge, Encyl. Brit. 1875,
ii ; Jones, An. Kingd. 1870 ; Gegenbaur,
Vergl. Anat. 1878 ; Walker, Brit. Spiders
(Ray Soc.) : Murray, Econ. Ent. p. 33.

ARACHNID'IUM, Hincks.— A genus of
Ctenostomatous Polyzoa (Bryozoa), fam.
Arachnidiidse.

Three British species.
BIBL. Hincks, Polyzoa, 1880, p. 508.
ARACHNOID MEMBRANE (Tunica
arachnoided). — Is a delicate transparent
membrane, lying between the cranial dura
mater and the brain, and extending between
the spinal cord and its dura mater so as to
envelope these nervous centres. It does not

dip between the convolutions of the brain,
but enters and lines its ventricles. Its outer
surface is covered by a delicate epithelial
layer ; its inner surface is smooth, but not
covered with epithelium. It is reflected
upon the surface of the dura mater as an
epithelial layer only. It consists principally
of reticulated bundles of connective tissue,
with fibres of elastic tissue coiling around
or pursuing a rectilinear course through
them. In some parts the fibrillse of the
former run parallel without forming bundles,
and contain, as do the bundles, round, elon-
gated, or spindle-shaped nuclei. In others,
connective tissue of a rather homogeneous
appearance here and there forms a coat to the
bundles, or is situated between them.

Fig. 29 represents two bundles of the
connective tissue of the human arachnoid,
after the addition of acetic acid, showing
the fibres of elastic tissue.

Fig. 29.

Connective and elastic tissue of arachnoid, after treat-
ment with acetic acid. Magnified 350 diameters.

BIBL. Kolliker, Mik. An. ii.: Henle,-4#-
aem. Anat.

ARACHNOIDIS'CUS, Bailey (Hemi-
ptychus, Ehr.). — A genus of Diatomaceae.

Char. Frustules adherent, disk-shaped;

ARACHNOSPIS.

ARCELLA.

valves plane or slightly convex, with radia-
ting and concentric lines (rows of dots), and
a central pseudo-nodule.

The markings upon the inner valves are
not the same as those upon the outer (or
parent) : hence the mere variations of the
markings are not characteristic ; nor is the
number of rays constant.

A. ornatus, Ehr. Valves very finely gra-
nular ; rays 29, equal. In Patagonian guano.

A. Ehrenbergii, Bail. Pseudo-nodule sur-
rounded by an inner ring of linear radiating
and an outer ring of circular or angular
markings (depressions) ; marine ; breadth
1-200 to 1-60" ; occurs also in guano. (PI.
16. figs. 12 & 13, side view.)

A. indicus (PI. 61. fig. 3). I yg$£

A. nicobaricus (PI. 51. fig. 4). jlglandg

BIBL. Ehr. Ber. d. Berl Ak. 1848 &
1849 ; Smith, Br. Diat. i. p. 25 j Shadbolt,
Tr. Mic. Soc. iii. ; Arnott, Micr. Jn. 1858,
p. 159; Greville, Micr. Tr. 1865, p. 47.

ARACHNOS'PIS, Kent.— A genus of
Infusoria, fam. Halteriidae.

BIBL. Kent, Infus. p. 214.

ARACHNU'LA, Cienk.— A genus of
Rhizopoda.

Char. Naked, colourless, without nucleus ;
one or more contractile vesicles ; pseudo-
podia branched, very slender, anastomosing;
bodies connected by thickish cords. Move-
ment active.

A. impatiens. In brackish water. Black
Sea.

BIBL. Cienkowski, Sch. Arch., 1876, xii.
p. 27.

ARANE'IDA.— A family of Arachnida,
comprising the true spiders.

The species of genera belonging to this
family (as A. civilis and domestica, house-
spiders, Epeira diadema, garden-spiders &c.)
are readily accessible for examining the
structural peculiarities of spiders — the skin,
the eyes, the organs of the mouth, the max-
illary palpi, the spinnerets, the legs, &c.
(See PI. 6.)

viii. ; Treviranus, Bau d. Arachn. ; Walker,
Brit. Spiders ; Murray, EC. Ent. p. 43.

ARAUC A'RI A, Jussieu.— A genus of Co-
niferae (Gymnospermous Flowering Plants),
remarkable for the character of the markings
on the walls of the cells of the wood, where
the pits or bordered pores appear in two or
more parallel rows (PI. 48. fig. 5). Arau-
caria (Eutassa) excelsa is the Norfolk-Island
Pine, which grows to an immense size, as

do also A. brasiliemis, A. imbricata, &c.
The reservoirs of turpentine seem to be in
the bark and not in the wood. See CONI-
FERS, WOOD, and SECONDARY LAYERS.

ARAUC ARI'TES, Goeppert (Dado.rylon,
Endlicher ; Pinites, Lindl. and Hutt.). — A
genus of Fossil Coniferae, characterized by
a structure resembling that of Araucaria.

BIBL. Witham, Fossil Vegetables, p. 72,
pi. 4-11. Edinb. 1833 j Lindley and Button,
Fossil Flora, \.i. 2,3.

ARCEL'LA, Ehr.— A genus of Rhizo-
poda, of the family Arcellina.

The Arcellae correspond to Amoebae con-
tained in a carapace. In some species the
carapace is membranous and uniform ; in
others it is calcareous and exhibits fine striae,
depressions, or granules spirally arranged.

A. vulgaris (PL 30. fig. 140). Carapace
brownish yellow, plano-convex, or hemi-
spherical, covered with depressions. These
markings or depressions are very beautiful
and interesting. They agree with those
upon the valves of the Diatomacese in re-
gard to the requirements for their display ;
with unilateral oblique light, lines only are
visible. Their true structure resembles that
in PI. 15. fig. 41, or PI. 17. fig. 29, except
that the rows are somewhat wavy or even
spiral. Fr. wat. ; breadth 1-500 to 1-200".
In the young state it is very transparent and
pale,"and the markings are with difficulty di-
stinguished. The shell is cast several times
before arriving at maturity. PL 32. fig. 24
represents the animal with its processes pro-
truding from the carapace.

We have seen two of these animals con-
jugating, and so firmly united by the soft
internal substance, that they were not sepa-
rable by rolling them over between two
plates of glass.

A. (Echinopyxis) aculeata (PL 30. fig.
14 b). Carapace brownish, discoidal, con-
vex above, with one or more irregular spi-
nous prolongations at the margin ; fr. wat. ;
breadth 1-200" without the spines.

A. dentata (PL 30. fig. 14 c). Hemi-
spherical, anguloso-polygonal ; carapace
membranous, homogeneous, yellowish or
greenish ; fr. wat. ; breadth 1-560 to 1-200".
A. aureola {Cyphidium aur oleum, Ehr.)
(PL 30. f. 38). Carapace yellow, angular,
with numerous tubercles, four of which are
larger and more projecting ; a single expan-
sion of varied size ; breadth 1-560 to 1-420";
fr. wat. Fig. 38 a represents the carapace
viewed from above, b the same supported
upon one angle, and the single expansion.

ARCELL1NA.

ARCYRIA.

A. arenan'a- in sand, under moss and
lichens. Other species.

BIBL. Ehrenberg, In/us. ; Claparede
and Lachmann, In/us, p. 444; Biitschli,
Schultze's Arch. xii. 459 (pi.).

ARCELLI'NA, Ehr.— A family of Lo-
bose Rhizopoda.

Char. Animals contained in a univalve
membranous or solid inflexible carapace,
of an urceolate or shield-like form, with a
single orifice from which one or more irre-
gular and variable expansions are protruded,
which form the organs of locomotion.

Biitschli describes conjugation ; but the
result is doubtful.

The substance of the body resembles that
of an Amoeba. Gen. : —

Shell flexible, dorsal Pseudochlamys.

Shell flexible, universal Amphizoiiella.

Shell solid, inflexible.

Not incrusted with foreign matters. Arcella.
Incrusted with agglutinated fo-
reign matters.

With tubular prolongations Echinopyxis.

Without tubular prolongations. . . Difflugia.

ARCILEDIS'CUS, Brady.— A small,
lenticular, asymmetrical, hyaline Fora-
minifer, of the Nummuline type ; found in
the Carboniferous Limestone.

BIBL. Brady, Ann. N. H. 1873, xii. 286.

ARCHEGO'NIUM. Also called pistilli-
dium. — The rudimentary organ representing
the ovule in the higher Flowerless Plants,
such as Mosses, Ferns, &c. (excluding the
Thallophytes). These organs are more mi-
nutely described under the heads of the
various Classes, in speaking of their repro-
duction.

In the Mosses and Liverworts they are
flask-like cellular bodies, found in terminal

Fig. 30.

Fig. 81.

Archeeonia of Mosses.
Magnified 50 diameters.

or axillary buds on the leafy stems (figs. 30
& 31). In the Ferns and Equiseta they are
produced on the prothallium, after the ger-

miDation of the spores. In the Lycopodi-
aceae and MaisHeaceae they are produced
upon the cellular plate, representing a pro-
thallium, developed in the large spores when
these begin to germinate. The corpuscula of
theConiferse are analogous bodies to the last.

EQUISETACE^E, LYCOPODIACE^E, MARSILE-
ACE^ ; also CONIFERS and CHARACEJE.

ARCHID'IUM,Bridel.— AgenusofPhas-
caceae(AcrocarpousMosses), of which but one
species is found in Europe (A. phascoides=
Phascum alternifolium, Hook, and T.), grow-
ing upon banks and fallow ground, on clay
or chalky soil. It is remarkable for the
sessile globular capsule, without a trace of
an operculum, the columella soon oblite-
rated, and the spores being few in number,
very large and angular in form (figs. 32 &

Fig. 32.

Fig. 33.

Archidium.

Open capsules devoid of columella and with large
spores. Magnified 40 diameters.

33). The calyptra is torn away in the mid-
dle during the expansion of the capsule, as in
Sphagnum, leaving a short tumid vaginula.

BIBL. Wilson, Bryol. Brit. p. 24.

ARCTO'A, Br. and Sch. = DiCRANiiM.

ARCYR'IA, Hill.— A genus of Myxo-
mycetes, growing on rotten wood, with' fre-
quently bright-coloured spores and fila-
ments. The elastic filaments of the capil-
litiurn have no spiral fibres, but are a little
tuberculated. The species in general are
not confined to Europe or the United States,
but have a very wide geographical range,
occurring in tropical and subtropical dis-
tricts as well as in those which are tem-
perate. Species : —

A. punicea, Pers. Common j spores and
capillitium purplish vermilion. A dark form
is separated by Rostafinski as A. ferru-
ginea. Grev. So. Crypt. Fl. t. 130.

A. incarnata, Pers. Not uncommon ;
smaller, with a shorter stipes and with flesh-
coloured spores and capillitium.

A. cinerea, Bull. Spores and capillitium
cinereous.

A. nutans, Bull. Spores and capillitium
dirty-yellow ; capillitium nodding. Tiichia

A REG A.

[ 72 ]

ARRE1SIURUS.

nutans, Sowerby ,t. 260 ; Arcyriaflava, Grev.
Sc. Crypt. FL t. 309.

A. umbrina, Schum. Spores and capilli-
tium ochraceous, capillitiuin erect; peri-
dium ovate.

A. ochroleuca, Fr. Spores and capilli-
tium pale-ochraceous, peridium globose,
evanescent; smaller than the preceding;
1-12" high.

B[BL. Berk. Hooker's Brit. Fl. ii. pt. 2.
p. 318; Crypt. Sot. p. 337; Fries, Summa
Veget. p. 456; Rost. Sluzowce ; Cooke,
Myx.

ARE'CA,L. — A genus of flowering plants
(Fam. Palmaceae). The albumen of the seed
of the Areca catechu (the Areca nut, as it is
called) affords a good instance of horny con-
sistence produced by secondary layers upon
the cell-walls (PL 38. tigs. 21 & 22). See
ALBUMEN (of seeds).

AREG'MA, Fries. — A genus of Conio-
mycetous Fungi closely allied to Puccinia,
comprising the species with many cells
which occur on various Rosaceae, as the
common dark parasite of the Rose and
Bramble. Like Puccinia, the species always
seem connected with a Uredinous form, and
are propagated by secondary spores pro-
duced on the multiseptate bodies after ger-
minating.

BIBL. Fries, Summa Veg. p. 507 ; Berk.
Crypt. Bot. p. 325 ; Tulasne, Ann. d. Sc. Nat.
1847, Jan. p. 12; De Bary, Ueb. d. Brand-
pilze.

ARE'OLAR TISSUE of animals. See
CONNECTIVE TISSUE.

AR'GAS,Walck. — A genus of Arachnida,
of the order Acarina and family Ixodea.

Char. Rostrum inferior, concealed, as also
the palpi, beneath a projection of the ante-
rior part of the body ; under part of body
granular, not scaly, and consisting of a single
piece ; first joint of the palpi longest ; legs
approximate at their insertion, feet termi-
nated by two claws, but no vesicle.

These animals are frequently parasitic
upon pigeons, fowls, &c. ; some live in
gardens.

A .reflexus( Tthynchoprion Cb/wm&^,Herm. ) .
Body marked with tortuous furrows and de-
pressions, yellowish or violet after food. On
pigeons, especially when young.

A. persicus. Blood-red colour, back co-
vered with scattered elevated white spots.
The venomous bug of Persia ; said to cause
death in the human subject.

There are other species.

BIBL. Gervais, Walcken. Apteres, iii. ;

Murray, EC. Entom. 180 (figs of all species) ;
Megnin, Paras. 1880, 133.

AR'GULUS, Mull.— A genus of Crusta-
cea, of the order Siphonostoma and family
Argulidae.

Char. Carapace membranous, covering
the cephalothorax like a shield ; antennae
four, short, concealed beneath the carapace,
anterior two-jointed, terminal joint hooked ;
posterior four-jointed; rostrum acuminate ;
five pairs of legs, the place of the first (6th)
pair being occupied by two suckers ; second
pair short, five jointed, the two basal joints
spinous, the last joint with two small hooks ;
the last four pairs of legs two-cleft, and
furnished with ciliated filiform processes.

A.foliaceus (PI. 20. fig. 1). Parasitic on
the stickleback (G aster ostem) and other
fishes ; carapace greenish.

BIBL. V. d. Hoeven, Zool. ; Baird, Brit.
Entom. p. 242 ; Thorell, Ann. N. H. 1866,
xviii. p. 149.

ARPAC'TICUS, Baird.— A genus of
Entomostraca, of the order Copepoda and
family Cyclopidee.

Char. Head undistingriishable from tho-
rax ; foot-jaws two pairs, forming strong
cheliform hands; antennae in male furnished
with a swollen hinge-like j oint ; antennules
(inferior antennae) simple; legs five pairs,
the fifth pair rudimentary; eye single; ovary
single. Two species : —

A. chelifer and A. nobilis. Marine, closely
resembling Cyclops.

BIBL. Baird, Brit. Entom. p. 212.

ARRENU'RUS, Duges.— A genus of
Arachnida, of the order Acarina and family
Hydrachnea ( = Caudate Hydrachnae).

The posterior part of the body of the male
is narrowed and produced into a truncate or
cylindrical appendage. The body of the fe-
male is truncated posteriorly. The prolon-
gation is terminated by two angles and a
sinuous intervening margin. At the middle
of the latter is situated the penis; above
which are two hooks. In both sexes the
back is hard, crustaceous, as if shagreened,
or spinous. In some species the thicker
layer of the skin is furnished with a number
of conical apertures (PI. 6. fig. 12). The
eyes are two, distinct, blackish. The intes-
tinal caeca are distinguishable through the
skin. The mouth is round and surrounded
by a kind of hood (PL 6. fig. 13, c).

Arrenurus viridis, Duges's typical species
(PL 6. fig. 13), has the palpi short and cla-
vate (a); the fourth joint longest and largest,
the fifth falcate, and the mandibles ungui-

AEROW-KOOT.

C 73 ]

ARTERIES.

culate (6). According to Murray, this is the
male of Atax histrionicus !

The species are very numerous and of almost

all colours — red, green, yellow, grey, purple.

BIBL. Walcken. Apteres, iii.; Duges, Ann.

d. Sc. N. 2 ser. i. j Koch, Uebersicht $c. ;

Murray, JSc. Ent. p. 154.

ARROW-ROOT.— A name given to va-
rious kinds of starch, derived from the plant
Maranta arundinacea and other species.
True West-India arrow-root is from this
(PL 46. fig. 26) and M. allonga and M. no-
bilis (N. 0. Marantaceae). East-India arrow-
root is obtained from species of Curcuma
(N. O. Zingiberacese) (PI. 46. fig. 19), and
apparently also from a Sagus, if we may judge
from a specimen (PI. 46. fig. 18) from Singa-
pore. Tahitan arrow-root (PI. 46. fig. 22) is
obtained from the plant called Tacca pinna-
tifida (N. 0. Taccaceae) ; and the substance
called Portland arrow-root (PL 46. fig. 1 1)
is extracted from the Arum maculatum (N.
O. Araceae), a common hedge-weed in this
country. In all these cases the fecula con-
sists of starch-grains, which are produced in
great quantity before the season of rest, in
the succulent tubers or rhizomes of the
plants; the arrow-root is extracted from the
grated root-stalks by washing, to separate
the cellular tissue and remove the often
acrid juices. See STARCH.

The arrow-root of the shops is subject to
adulteration with cheaper kinds of starch,
especially with sago and potato-starch.

BIBL. Pereira, Mat. Med. ; Hassall, Food
and its Adulterations, p. 31.

ARSENIC.— The common term for arse-
nious acid. Arsenious acid assumes two
crystalline forms, and occurs also in an
amorphous state.

The most common form is the octahedral
or tetrahedral. The second (right rhombic)
is less common, and is only obtained by
sublimation. Attention to the form of the
crystals is important, because it is used as
a means of identifying arsenic in cases of
poisoning. It must, however, be borne in
mind that protoxide of antimony (Sb 03)
yields crystals by sublimation of exactly
the same form as those of arsenious acid
(PL 10. fig. 22).

Solution of arsenious acid is sometimes
used as a preservative liquid for animal
preparations.

BIBL. Guy, Mic. Tr. 1861, p. 54.
ARTE'MEA, Leach.— A genus of Ento-
mostraca, of the order Phyllopoda and fa-
mily Branchiopoda.

Char. Abdomen prolonged in the form of a
tail, composed of nine segments or joints, the
end joint simply divided into two lobes ;
superior antennae slender and filiform in both
sexes ; inferior antennae in the male large,
flat, curved downwards and two-jointed, re-
sembling horns; in the female short, pointed
and slightly curved; basal joint of male
inferior antennas provided with a short coni-
cal process.

A. salina. The Lymington shrimp or
brine-worm. Found in the salt-pans at
Lymington. Length about 1-2".

Each segment of the thorax shortly bi-
lobed at the apex, and with a pair of bran-
chial feet; each lobe of the end joint of abdo-
men giving off several short setae. Agrees
generally in structure with Branchipus.

BIBL. Baird, Brit. Entom.; Rackett,
Linn. Tr. xi.

ARTERIES.— These are the tubes or
vessels which convey the blood from the
heart to the various parts of the body. The
structure of the arteries is very complicated
and difficult of investigation ; and the coats
or tunics of which they consist are so inti-
mately connected as to be by no means
easily separable.

In the larger arteries, three coats are
usually distinguishable, an outer or adven-
titious coat, a middle, and an inner coat or
intima, with its epithelial lining. Their
composition and thickness vary in arteries
of different sizes.

The general character of the arteries is
that the middle coat is thick and strong,
consisting of several layers, and its elements
run transversely. In the largest arteries it
is yellow, very elastic and of great strength ;
as the vessels become smaller, it diminishes
in thickness, becoming redder and more
contractile ; and near the capillaries it is very
thin, finally disappearing. The inner coat
is always thin, yet thickest in the large ves-
sels ; whilst the outer coat is absolutely
thinner in these than in those of a moderate
size, in which it equals or even exceeds the
middle coat.

In the small arteries the epithelial lining
consists of very delicate pale, flattened, fusi-
form cells with longish oval nuclei.

An elastic layer is expanded beneath the
epithelial layer, which is smooth in the
living vessels, whilst in these, when empty,
it exhibits numerous transverse or longitu-
dinal folds. It form s what is called a fenes-
trated membrane, generally exhibiting more
or less distinct reticulated fibres, and usually

ARTERIES.

C 74 ]

ARTERIES.

small elongated openings ; more rarely a
very dense network of principally longitudi-

Magnified 350 diameters.

JTA small artery (a) and vein (6) (about 1-180" in diameter) from the me-
sentery of a child, after the addition of acetic acid : a, external coat, with
elongated nuclei ; /3, nuclei of the muscular fibres of the middle coat, partly
seen from the surface, partly the sectional view ; y, nuclei of the epithelial
cells ; S, fibrous layer of elastic tissue.

nal elastic fibres, with narrow elongated
fissures.

Fig. 35.

Magnified 350 diameters.

Muscular fibre-cells from human arteries. 1, from
the popliteal ; a, before, b, after the addition of acetic
acid ; 2, from a twig of the anterior tibial artery : o,
nuclei.

The middle coat of the smaller arteries is
purely muscular. The fibres or fibre-cells,
which are transverse and
connected into layers, may
be isolated by dissection,
or by maceration and boil-
ing in a mixture of nitric
acid with four parts of
water.

The outer coat consists
of connective tissue with
elongated nuclei and fine
elastic fibres, and is nearly
as thick as, or even thicker
than the middle coat.

In the smallest arteries,
the outer coat gradually
ceases to contain elastic
tissue, consisting merely of
areolar tissue and the nu-
clei; this gradually loses
its fibrous character, next
becoming homogeneous,
and finally a thin perfectly
structureless membrane,
and disappearing. In the
same manner the middle
coat gradually loses its lay-
ers of muscular fibres, until
these and the fibres them-
selves ultimately vanish.
On tracing the smaller
arteries downwards, the inner coat is first
found to lose its elastic fibres ; and at last
the epithelial cells cease to be isolable, all
that can be distinguished consisting of their
closely aggregated nuclei ; but by macera-
tion in very dilute solution of nitrate of sil-
ver, the lines of demarcation of the cell-
walls are rendered beautifully distinct.

In moderate-sized arteries the middle coat
increases in thickness, but, in addition to a
larger number of muscular layers, fine elas-
tic fibres in open networks are added, at
first running somewhat irregularly through
the muscular elements, and in the larger
vessels of this category mixed with areolar
tissue and here and there forming layers
alternating with those of the muscular fi-
bres. The inner coat sometimes contains
between its elastic layer and the epithelium
several other layers, forming, with fine net-
works of elastic tissue more externally
situated in homogeneous granular or fibrillar
areolar tissue, a strong middle layer, the
elements of which are longitudinal. The
outer coat in these vessels contains more
elastic tissue, in the form of Iamina3.

ARTERIES.

ARTHROBOTRYS.

In the largest arteries, the epithelial cells
of the inner coat are not so elongated, and
the inner coat consists principally of layers
of a homogeneous, striated, or even di-
stinctly h'brillar substance, agreeing with
areolar tissue, traversed by finer and coarser
longitudinal networks of elastic tissue. Im-
mediately beneath the epithelium the net-
works or elastic fibres are either very fine,
or are replaced by one or more striated
layers, which, when nucleated, often appear
as if composed of fused epithelial cells, and
when homogeneous resemble pale elastic
membranes. The middle coat contains, as
a new element, elastic membranes or plates,
as many as 50 or 60, which, except in their
transverse direction, resemble the elastic
-inner coat, sometimes forming the densest
networks of elastic fibres, at others fenes-
trated membranes. These layers alternate

Fig. 36.

Magnified 30 diameters.

Transverse section of the human aorta below the superior mesenteric ar-
tery, after acetic acid. 1. Inner coat : a, epithelium ; b, striated layers ; c,
elastic layers. 2. Middle coat : d, its elastic layers ; e, the muscular and
areolar tissues. 3. Outer coat with its network of elastic tissue.

with those of the muscular fibres traversed
by areolar tissue and networks of elastic
tissue. The muscular layer of the middle
coat is less developed, its cells smaller and
less regularly and perfectly formed.

The outer coat is relatively and absolutely
thinner than that in the smaller j but the
structure is the same, except that its inner
elastic layer is much less developed.

In some of the larger arteries of man, as
the axillary and popliteal, and the mesenteric
arteries of other mammals, the internal coat
contains unstriped muscular fibres. This
is the case also with the outer coat of
the larger arteries in animals, but not in
man.

All except the smallest arteries are fur-
nished with nutrient blood-vessels, the vasa
vasorum ; these ramify principally in the
outer coat, in the larger ones extending into

the middle coat. They also receive branches
of the sympathetic and spinal nerves.

Transverse sections of the arteries are
best made with the freezing; section-cutter
or microtome. The epithelial cells require
the use of solution of nitrate of silver.

The most important pathological changes
to which the arteries are subject, consist of
the deposition of fat in their substance
(fatty degeneration) and of atheromatous
matter. These will be noticed under FATTY

DEGENERATION and ATHEROMA. See

VESSELS.

BEBL. Henle, Allg. An. ; Kolliker, Ge'we-
belehre; Wedl, Path. Hist.-, Rokitansky,
Krankh. d. Art.-, Frey, Histologie, 1881;
Eberth, Strieker's Handbuch, y. p. 190;
Rutherford, Hist. p. 100 ; Cohnheim, Pathol.
1878, p. 168.

ARTHO'NIA, Ach.— A genus of Li-
chenaceous Lichens, tribe
Graph idei.

Char. Thallus thin or
subepidermal and evanes-
cent; apothecia dark, in-
nately sessile ; asci pyri-
form; spores 4-8, septate,
upper cell larger ; no para-
physes.

32 species, some common ;
on trees, holly, ash, oak &c.
BIBL. Leighton, Lich.
Flora, 1879, p. 414.

ARTHRIN'IUM, Kze.
— A genus of Dematiei
(Hyphomycetous Fungi),
of which one species has
been found in Britain,

growing upon dead leaves of Eriophorum
angustifolium.

A. sporophlceum, Kze. Filaments elon-
gated, tufted, often not more than 1-50"
long, but frequently confluent in a linear
form, with a kind of velvety surface; spores
numerous,angular, or like a double cone, at-
tached in whorlsatthe joints of the filaments.

BIBL. Berkeley, .4 wi.^V.#; 1838, i.p. 436 ;
Torula Eriophori, Berk. Enql. Fl. v. pp. 2,
359 ; Fries, Sum. Veg. p. 502.

ARTHROBO'TR'YS, Corda.— A genus
of Mucedines (Hyphomycetous Fungi) bear-
ing elegant nodular groups of septate spores.
No species is yet recorded in Britain.
Corda describes one species, A. superba (fig.
37) ; in this the spores are about 1-1500"
long. Fresenius describes another, A. oligo-
spora, perhaps not distinct, which has the
erect filaments about 1-50" high, solitary,

ARTHROBOTRYUM. [

not in tufts, and mostly with only one
group of spores ; these are pear-shaped,
1-700" long, and have the septum below
the middle : it was found on damp wood,
fruit and earth, in a fungus-bed.

Fig. 37.

Fig. 38.

Arthrobotrys superba.

37. Fertile filament with many groups of spores.

Magnified 200 diameters.

38. Fertile articulation of ditto, with most of the

spores detached from the spine-like pro-
cesses on which they are borne. Magnified
400 diameters.

BIBL. Corda, Schimmelb. p. 43, t. 21 ;
Fresenius, Beitr. zur Myc., Heft i. p. 18,
pi. 3. figs. 1-8.

ARTHROBO'TRYUM.— Agenus of Mu-
cedines (Hyphomycetous Fungi), proposed
by Cesati, characterized by a stem composed
of jointed threads, bearing above large
jointed radiating spores, so as to form B,
little head. They are beautiful microscopic
objects. British species : —

A. atrum, B. £ Br. On dead nettle-
stems.

A. stilboideum, Ces. On a pollard-willow.

BIBL. Berkeley, Out. Br. Fung. p. 342 ;
Hedwigia, tab. 4. fig. 1.

ARTHROCLA'DIA, Duby.— A genus of
Sporochnaceae (Fucoid Algse). A. villosa,
Hucls., is a rather rare British annual sub-
marine species, growing in 4 to 5 fathoms
water ; bearing a curious pod-like nucleated
fruit,

BIBL. Harvey, Brit. Mar. Alga, 2d ed.
p. 24, pi. 5 C. ; Phyc. Brit. t. Ixiv. ; ~Eng.
Bot. t. 546 ; Derbes and Solier, Ann. d. Sc.
Nat. 3 ser. xiv. p. 33, figs. 18-20.

ARTHRODES'MUS, Ehr.— A genus of
Desmidiaceae.

Char. Cells single, compressed, constricted

ARTOTROGUS.

in the middle; segments entire, with a single
spine on each side.

A. convergens. Segments elliptic (PL 14.
fig. 27) : length 1-598 to 1-539".

A. incus, Bre"b. Segments with truncated
ends ; length 1-1103".

A. minutus, Kiitz. (PL 18. fig. 9).

A. truncatus, Ehr.

A. subulatus.

Other species.

BIBL. Ralfs, Brit. Desmid. pp. 117, 200 ;
Kiitzing, Sp. Alg. p. 176 ; Ehreuberg, In/us.
p. 158 ; Rabenhorst, FL Alg. iii. p. 225.

ARTHROGY'RA, Ehr. — An obscure
genus of Diatomaceae.

A. guatemaknsis (PL 51. fig. 8). Fila-
ment straight.

A. semilunaris. Filament curved. Both
in Guatemala earth.

BIBL. Ehrenberg, Mikrogeoloqie, pi. 33.

ARTHROM'ITUS, Leidy.— Described as
a genus of the Leptothriceae of Kiitzing
(Algae Confervoidese). Two species, A. cru-
tatus and A. nitidus, were found in the in-
testinal canal of lulm marginatus, a kind of
millipede. These objects appear to have
been imperfect forms of some filamentous
Fungus. See PARASITES.

BIRL. Leidy, Proc. Ac. Philadelphia, iv.
p. 225, 1849 (Ann. N. If. 2nd ser. v. p. 74).

ARTHRONE'MA, Hassall.— A genus of
Oscillatoriacese (Confervoid Algae).

A. cirrhosum (PL 8. fig;. 20). Filaments
of considerable size, striae close, evident.
Tufts widely spreading, filaments floating
in bundles. In lakes at Lismore Island.

BIBL. Hassall, Brit. Alga, p. 238; Raben-
horst, Fl. Alg. ii. p. 267.

ARTHROSI'PHON, Kiitzing. See PE-

TALONEMA.

ARTICULI'NA, D'Orb.— Very narrow
varieties of Vertebralina, which commence
with a Milioloid (Triloculina) growth, and
proceed with straight moniliform chambers,
were separated by D'Orbigny under this
name. Recent and fossil.

Articulina gibberula (PL 23. fig. 9 a b).

BIBL. D'Orbigny, Ann. Sc. N. vii. 300 ;
Carpenter, Intr. For. 73.

ARTOTRO'GUS, Mont.— A genus of Se-
pedoniei (Hyphomycetous Fungi) contain-
ing one species, growing and fructifying in
the intercellular passages of germinating
potatoes. This genus is supposed by Berke-
ley to be founded on a secondary form of
fruit of some mould ; probably of Perono-
spora infestans. See PERONOSPORA.

A. tiydnosporus, Mont. Berkeley, Jn.

ARTOTROGUS.

ASCIDICOLA.

Horticutt. Soc. i. p. 3, pi. 4. figs. 27-29 ;
Crypt. Bot. p. 247 ; De Bary and Woronin,
Beit. iv.

ARTOTRO'GUS, Boeck.— A genus of
Entomostraca, Ord. Copepoda. Four British
species ; marine, living in the branchial sacs
of Ascidiee, or on the integument of marine
Invertebrata.

BIBL. Brady, Copepoda (Ray Soc.}, iii.
p. 59.

A'RUM, L. — A genus of Aracese (Flow.
Plants). Arum macidatum, the common
Cuckoo-pint, has a tuberous rhizome in
which is produced much starch. This starch
is extracted in the same way as Arrow-root
starch is from the rhizomes of Marantaceae
&c., and is called Portland Arrow-root (PI.
46. fig. 11). See STARCH.

AS'CARIS.— A genus of Entozoa, of the
order Coslelmintha and family Nematoidea.

Char. Body cylindrical, narrowed at each
end ; head furnished with three tubercles or
valves ; mouth terminal, situated between
the three tubercles j male with one or two
spicula.

The species are very numerous, occurring
in all the classes of theVertebrata and doubt-
fully in Insects. They are most commonly
found in the alimentary canal. We shall
only notice the species met with in man.

A. lumbricoides. The common round
wTorm. Inhabits the human small intes-
tine ; sometimes found also in that of the
ass, wild-boar, pig. and ox. Varies in length
from 3 to 15" ; is of a whitish colour ; the
head distinct, with the three valves (PI. 21.
fig. 9) finely denticulated on their inner
border, and each furnished near the summit
with a slightly projecting papilla. Female
larger and more common than the male.
Spicula two, equal.

The recent ova are surrounded by an al-
buminous layer, the surface being studded
with numerous projecting tubercles.

A. vermicidaris (Oxyitris verm}. The
human thread-worm. Found usually in the
rectum. White ; head frequently appearing
winged, or exhibiting two lateral vesicular
expansions (PI. 21. fig. 8 a}, produced by
endosmosis. Mouth round when contracted,
exhibiting the three lobes when expanded.
(Esophagus (e) containing a triquetrous
canal, and separated by a constriction from
the spherical stomach (d). Length, female
3 to 4-10 of an inch ; male shorter, with
the tail spirally coiled, much more rarely
met with. Anus (<?) about 1-8 from the end
of the body j spiculum single, with an ap-

Uterus consisting of two lobes
(h) (ovaries) ; oviduct (K) opening externally
near the middle of the body.

A. mystax (alata, Bell), 2 to 3 inches long,
as broad as a crow-quill ; common in the
cat, occasional in the human body.

A. nigrovenosa, with the intestine black,
is found in the lungs of the frog and toad ;
and parthenogenesis is supposed to occur.
The females live in the lungs. The young
pass into damp earth or mud, where they
grow into sexual forms also producing em-
Dryos, which do not arrive at sexual matu-
rity until they reach the lungs. No males
are found in the lungs.

BIBL. Dujardin, Helminthes ; Leuckart,
Mensch. Parasit. ii. p. 153 ; Downe, Mn.
Mic. Jn. 187.1, v. p. 55 (A. lumbr.) ; Cobbold,
Entozoa, 1879, p. 243 ; Duj. Helm. p. 178 ;
Leuckart, Paras., 1879, p. 128.

ASCHEMONEL 'LA, Brady.— Oneofthe
branching Arenaceous Foraminifera. The
chambers inflated, with 2 or more tubulated
apertures, any of which may produce a new
chamber.

BIBL. H. B. Brady, Qu. Jn. Mic. 1879,
xix. p. 44.

ASCIDTA, Bast.— A genus of Tunicate
Mollusca, of the family Ascidiadae.

Several British species. See ASCIDIAD^:.

ASCID'IADJE.— A family of Tunicate
Mollusca.

Distinguished by their being single,
usually fixed (to foreign bodies, as sea-
weeds, shells, &c.), and the attachment of
the mantle to the test at the orifices only.

Irregularly shaped, from half to several
inches long, often incrusted with stones and
shells, &c. ; with two orifices, one branchial
and pharyngeal, the other anal. British
genera :

Ascidia, Bast. Test leathery ; branchial
orifice eight-lobed, anal six-lobed, both cir-
cular ; branchial sac not plaited.

Molffula, Forbes. Globose, attached or
free ; test membranous, usually covered with
foreign matters; branchial orifice six-lobed,
anal four-lobed, both on contractile naked
tubes.

Cynthia, Sav. Sessile ; test leathery ;
branchial sac plaited longitudinally; both
orifices four-sided.

BIBL. Forbes and Hanley, Brit. Moll. i.

L29 ; Gosse, Mar. Zool. ii. p. 35 ; Pascoe.
ol. 1880, p. 171.

ASCIDIC'OLA, Thorell.— A genus of
Entomostraca, Ord. Copepoda. 1 species,
marine.

ASCLEPIADACE^E.

[ 78 ]

ASCOMYOETES.

BlBL.

p. 145.

Brady, Copepoda (Ray Soc.), i.

ASCLEPIADA'CE/E.— A family of Di-
cotyledonous flowering plants, presenting
some remarkable characters in the pollen
(see POLLEN). The stems of some of these
plants contain very tenacious fibres, which
nave been used ibr economical purposes
(see FIBRES, vegetable).

ASCOB'OLUS.— A genus of Helvellacei ;
distinguished from Peziza by the asci being
projected from the hymenium at maturity.
Ascobolus furfuracem is common on cow-
dung ; but there are numerous other British
species. The sporidia are often beautiful
microscopic objects (Cooke, Seemann's Jn.
Sot., May 1864).

ASCOCOC'CUS, Billr.— A genus (form)
of Coccobacteria septica, consisting of very
minute colourless globules, closely united
into globular or oval families, irregularly
lobed, surrounded by a thick gelatinous en-
velope, forming a soft, tiocculent, easily
disintegrated membrane. See COCCOBAO
TERIA.

ASCOGLE'NA, Stein.— A genus of Fla-
gellate Infusoria.

Char. Those of Eiiglena, enclosed in and
fixed by the base to a flask-shaped lorica.

A. vaginicola. Green, with eye-spot ; in
fresh water.

BIBL. Kent, Inf. p. 393 (fig.).

ASCOMY'CES.— A genus of Ascomy-
cetous Fungi, changed by some botanists,
without reason, into Exoa&cus, characterized
by the absence of any receptacle, the asci
forming a thin pulverulent stratum. All
the species are parasitic on living leaves or
young shoots. It is the lowest form to
which Ascomycetes can be reduced. British
species :

A. bidlatus. On pear-leaves.

A. deformans. On peach-leaves, produ-
cing a form of blister ; and on young plums,
forming what are called bag-plums, in which
the stone is not developed.

A. trientalis. On leaves of T. europaa.

A. juglandis. On walnut-leaves.

A. carnosa. On Rhododendron ferru-
ginettm, producing large gall-like excres-
cences.

BIBL. Berkeley, Jn. Hort. Soc. vol. ix.
p. 48 ; JBr. Fung. p. 376.

ASCOMYCE'TES.— An order of Fungi
characterized by producing the spores in
tubular sacs (asci or thecce), frequently in-
termixed with empty filiform sacs (para-
physes) (fig. 40), and hence bearing a near

relation to the Lichens, which, indeed, are
included under this order by some botanists ;
but the existence of green colouring-matter
in the cells, and of gonidia or brood-cells, in
the Lichens, forbids such an association.
The Ascomycetes differ much in external
form, and approach in this particular several
tribes belonging to the other orders : thus
the Tuberacei are very much like many of
the Gasteromycetes, the Helvellacei like

Fig. 39.

Fig. 40.

Spathulea flavida.

Fig. 39. Entire plant (reduced).

Fig. 40. Highly magnified section of fructification,
showing asci andparaphyses arising from the hymenium.

some Hymenomycetes, &c., differing chiefly
in the mode of the production of the sporidia
(figs. 39-42).

Fig. 41.

Fig. 42.

Leotia geoglossoides.

Fig. 41. Group of plants (reduced).
Fig. 42. Highly magnified asci with

ith spores.

The Onygenei are little Fungi growing on
dead animal substances, feathers, horn, £c.,

ASCOMYCETES.

ASCOMYCETES.

and have a flocculent mycelium, bearing
little columnar bodies terminating in a thick-
ened head — the sporange, which is a kind of
hood falling oft' at maturity. The sporifer-
ous structure, loosely filling up the hood, is
composed of interlacing branched filaments,
bearing at their free ends globular cells
(asci or thecce) filled with spores.

The Perisporiacei are likewise very simple,
consisting of parasitical Fungi growing upon
the leaves of trees or herbaceous plants.
They have a flocculent mycelium, often
radiating from a centre, where is found a
membranous, sac-like, globular conceptacle,
containing sometimes a definite, sometimes
an indefinite number of clavate sacs or asci,
alone or mingled with paraphyses, and
containing ovate spores. The conceptacle
bursts either regularly or irregularly at the
summit.

The Sphaeriacei have the conceptacles
more developed, either single, or associated
on a common receptacle, and consisting of
a firm capsular structure, lined with asci, and
opening at the apex by a regular pore in the
form of a papilla or beak when mature.

The Phacidiacei differ chiefly in the de-
hiscence by slits, either single or longitu-
dinal, or several and parallel or stellate, or
circular so as to detach a lid ; most of these
have the sporanges collected on a common
receptacle, either of horny or fleshy consist-
ence.

In these two families, and in Helvellacei,
Coniomycetous forms of spore are found
upon the same receptacle, either contem-
poraneously or at different stages of deve-
lopment. Attention is directed to this sub-
ject under the head of that order ; and more
will be found under SPH^ERIA, TYMPANIS,
RHYTISMA, DOTHIDEA, CORDICEPS, &c.

The true Tuberacei are Ascomycetous re-
presentatives of the Hypogasous Gasteromy-
cetes, being subterraneous, solid, globular
or lobed bodies, of fleshy consistence, the
Truffle being a well-known example. The
organization of the Tuberacei is analogous
in all cases, but the structures differently
arranged. They all have an inconspicuous
flocculent mycelium, from which arises the
solid sporange. The sporange exhibits, when
cut across, an outer tough coat (jMrt&tmt),
enclosing a fleshy structure excavated with
sinuous cavities giving it a marbled appear-
ance. These sinuous cavities are produced
by the convolutions of the fructifying
layer, which is folded and reflected back-
wards and forwards, leaving interstices

which are lined with the asci or spore-sacs
containing four or eight spores. The de-
gree of complexity of the lacunose mass
differs in different genera, being in some
simple, in others very complicated.

The fructification of the Helvellacei varies
much in form, the simpler resembling
closely some of the Phacidiacei : some kinds
are minute fleshy cups lined with asci form-
ing a superficial layer, as in Propolis ; or
they are large fleshy cups, often raised on a
stalk (Peziza), these cups being closed at
first, but opening widely afterwards. In
the Helvellce, the cup is converted into a
stalked mitre-shaped body clothed above
with asci. Others are of columnar form,
thickened at the summit, which is clothed
with the asci, as if a cup-shaped receptacle
had been turned down over it (Spathulea^
fig. 39) — this thickened head becoming more
considerable and excavated into little pits in
Morchella. These plants are mostly found
on the ground or decaying vegetable sub-
stances, in damp places, and are frequently
of gelatinous consistence.

If a Peziza, Morchella, Rhytisma aceri-
num, or similar Fungus, in its last stage of
development, is kept shut up in a bottle for
several hours, and then gently taken out,
the contact of the external air causes an im-
mediate and abundant explosion of spores,
which may be collected on slips of glass for
microscopic examination. If care is taken
in the experiment, it will be found that a
considerable quantity of a colourless liquid
is expelled with the spores, which liquid
contains minute molecules, and evaporates
very rapidly, leaving more or less apparent
spots on the glass. See SPELERIA.

Synopsis of the Families.

HELVELLACEI. Fruit fleshy, of various
forms, ultimately expanded, clavate, capi-
tate, stalked, mitre-shaped, cup-shaped or
bell-shaped, the upper surface clothed by
elongated sacs (asci), each containing eight
simple or septate spores.

TUBERACEI. Fruit (subterraneous) glo-
bular, with an adherent peridium ; solid
and fleshy within, and excavated sinuously
into numerous cavities clothed by asci con-
taining four or eight spores ; the internal
mass drying up or becoming pulverulent or
floccose when mature.

PHACIDIACEI. Fruit fleshy, simple or
branched, more or less cup-shaped in the
sporiferous region, which opens widely
or by a slit when mature, and exposes a

ASCOPHORA.

ASPERGILLUS.

cavity lined with elongated asci mixed with
paraphyses.

SPHLERIACEI. Fruit usually forming a
common, often horny, receptacle, in which
are excavated conceptacles, lined with asci,
opening by a terminal pore.

PEEISPOBIACEI. Common receptacle floe-
cose, radiating from a centre, bearing con-
ceptacles free or surrounded by filaments,
opening by a terminal pore, with asci at-
tached at the base filled with simple ovate
spores.

ONYGKENEI. Mycelium floccose, bearing
capitate, stalked sporanges, which open
by a circular slit at the base, causing the
upper part to fall off like a cap ; exposing
a fructifying mass composed of interlacing
branched filaments, bearing globular asci at
the free extremities of the branches.

BIBL. See under the heads of the Families.

ASCOPH'ORA, Tode. See MUCOB.

ASCOT'RICHA, Berk.— A genus of Peri-
sporiacei (Ascomycetous Fungi), containing
one species.

A. chartarum, a kind of mildew growing
on paper, forming a brownish, angularly and
dichotomously branched mycelium, from
which arise globose, black, hairy peridia con-
taining linear asci, each containing a single
row of chocolate-coloured spores. Peridia
from 1-20 to 1-30" in diameter.

BIBL. Berkeley, Ann. N. H. 1838, i. 257,
pi. 7. fig. 8.

AS'CUS.— The term applied to the cylin-
drical globose or clavate tubular sac forming
the parent cell of the sporidia in the Asco-
mycetous Fungi. It is frequently called a
theca also (tigs. 40 and 42). Asci consist
of a double membrane, the inner often
visibly projecting when the ascus is broken
across. A little lid is frequently separated
from the apex when the sporidia are dis-
charged, as in Ascobolus, in which genus
the asci are shot out from the common
hymenium. See ASCOMYCETES.

BIBL, Mag. ZooL $ Bot. vol. ii. p. 222 ;
Pringsh. Jahrb. Bd. i. p. 189 ; Cooke, Hand-
book.

ASEL'LUS, Geoffrey (the water wood-
louse). — A genus of Crustacea, of the family
Isopoda.

Char. Antennae four, outer much longer
than the inner ones ; legs shorter than the
body, the first pair not chelate ; two poste-
rior projecting bifurcate abdominal appen-

A. vulgaris (PI. 18. fig. 13). Length 1-4
to 1-2" or more. This animal is particu-

larly interesting to the microscopist, on ac-
count of its forming the most readily pro-
curable object for examining the dorsal
vessel and circulating liquid in motion. It
is found in almost all stagnant waters. The
currents of the circulating liquid, with
the colourless corpuscles, are readily seen
streaming through every part of the body.
Beneath the large scutiform joint of the
body (the abdomen), are three flattened
branchial false legs or gills on each side,
covered by two jointed gill-covers j these
are in almost constant motion during life.

BIBL. Desmarest, Consid. Gen. 8. I. Crus-
taces ; Treviranus, Vermischte Schriften, i.

Fig. 43.

M.-Edwards, Crustacts, iii. (Suites a J5uf-
fon).

ASPERGIL'LUS, Micheli.— A genus of
Mucedines (Hyphomycetous Fungi) forming
common mould, such as the blue mould of
cheese, A. glaucus. The chains of spores
arise from a more or less globular head at
the apex of the fertile
filaments (fig. 43). It is
often stated that the
heads of spores are origi-
nally enclosed in a peri-
diuni j according to our
observations this is not
the case ; the spores bud
out from the capitular
cell, which enlarges very
much during the forma-
tion of the head of spores ;
and when these have been
detached, the head is left
bare, but covered with
short spiny processes (the

points Of attachment of

the chains of Spores), and with chains of spores

thenlookssomethi^Hke ^iS™!.-

a young peridmm 01 Mu- meters.

cor. Aspergillus has been

found to produce a secondary form of fruit,

being that forming the subject of the genus

EUBOTIUM. British species :

* Fertile Jilaments simple.

A. glaucitS) Link. Sporidia globose, va-
riable, white to glaucous, close (A. candidtts,
Link) or lax. Heads about 1-100" in dia-
meter when mature. On cheese, lard, bread,
&c., very common (fig. 43). It has been found
also in the lungs and air-cavities of birds,
Mucor glaucus, L.

A. roseus, Lk. Sporidia globose, very
small, rose-red ; fertile filaments not sep-
tate. On damp paper, lint, carpet, &c.

A8pergilius giaucU8.

fertile filament

ASPEROCOCCUS.

ASPIDISCA.

A. aureus, Berk. Sporidia large, ellipti-
cal, tliinly scattered, golden-yellow ; fertile
filaments without septa. On bark. Now
referred with A. aurantiacus, from which
it scarcely differs, to the genus Rhinotri-
chiim.

A. aurantiacus, Berk. Sporidia oval,
the lowest of the chain much larger, myce-
lium rusty orange, the heads often prolife-
rous, so as to produce a complicated mass.
On bark. Ann. N. H. vi. p. 436, pi. xiii.
tig. 22. Nematogonium aurantiacum,
Desmaz. Ann, des Sc. Nat. 2 ser. ii. p. 69,
pi. 2. fig. 1.

** Fertile filaments branched.

A. maximuS) Lk. Sporidia very large,
at length yellow-brown, mycelium a fleecy
mass of the same colour ; fertile filaments
dichotomous, clavate above. On decaying
Fungi.

A. mollis, Berk. Sporidia large, sub-
globose, white, mycelium white ; fertile
filaments dichotomous. standing in minute,
scattered, white bundles.

A. virens, Lk. Sporidia, like the fila-
ments, greenish ; tufts of fertile filaments
rather dense, entangled, suberect. On de-
caying fungi and other bodies.

A. alternatus, Berk. Sporidia grey- black,
subtruncate ; fertile plants branched alter-
nately in a zigzag manner, erect or decum-
bent, forming extremely minute orbicular
patches on damp paper. Ann. N. H. 1838,

1. p. 262, pi. 8. f. 11.

A. dubius, Corda, would appear to differ
generically from the above. Mr. Berkeley
states that its capitular cells bear linear
processes, each surmounted by four sterig-
rnata, on which are attached the chains of
spores. On dung. Corda, Ic. ii. t. 11.
fig. 77.

BIBL. Berkeley, Hooker's Sr. Fl. ii. part

2, p. 349; Ann. N. H. i. 262, vi. 436, 2nd
ser. vii. 100; Crypt. Sot. p. 298; Fries,
Syst. Mycolog. iii. 383 ; Corda, Ic. Fung. ;
Robin, Parasites, p. 615.

ASPEROCOC'CUS, Lamour.— A genus
of Dietyotaceae (Fucoid Algse), of which
three species are found on the British coast.
The fructification consists of groups of spo-
ranges (commonly called spores), intermixed
with paraphyses, scattered over the whole
surface of the frond. When mature these
sporanges discharge zoospores.

BIBL. Harvey, Mar. Algce, 2nd ed. p. 42,
pi. 8 C. ; Phyc. Brit. t. xi., Ixxii. and cxciv.;

Thuret, Ann. Sc. Nat. 3 ser. xiv. p. 238 ;
Derbes and Solier, ibid. p. 268, pi. 34. fig. 11.

Fig. 44.

Fig. 45.

Asperococcus Turneri, Dillw.
Fig. 44. Fronds, reduced to one third.
Fig. 45. Fragment of ditto, magnified 50 diameters.
Fig. 46. A section at right angles to fig. 45, showing the
sporanges and paraphyses, magnified 50 diameters.

ASPIDIE'^E.— A family of Polypodi-
aceous Ferns, with indusiate sori. Genera :

Didymoclilcena. Sori elliptical, intramar-
ginal, terminal on a veinlet ; indusium ob-
long-elliptical, emarginate at base, attached
to the linear receptacle, free at edge.

Aspidium. Sori rounded, dorsal or ter-
minal ; indusium orbicular, peltate.

Nephrodium. Sori rounded, dorsal or ter-
minal; indusium cordato-reniforni, attached
by the sinus.

Nephrolepis. Sori round, arising from
the apex of the upper branch of a vein,
generally near the edge ; indusium roundish
or reniform ; veins free.

Oleandra. Son round, in a row near the
base of the compact free veinlets ; indusium
reniform.

Fadyenia. Sori oblong, biserial, termi-
nating free veinlets ; indusium large, sub-
reniform, attached by the centre, free at
margin.

BIBL. See FERNS.

< ASPIDIS'CA, Ehr.— A^genus of Infuso-
ria, of the family Aspidiscina.

Char. That of the family.

A. (Trichoda, Mull.) lynceus (PI. 30. fig.
15 «, under view). Carapace suborbicular,
truncated posteriorly, uncinate anteriorly
aquatic, among Conferva* &c.: length 1-
1100 to 1-560".

A. denticulata (PI. 30. fig. 15' 6, side
view). Carapace suborbicular, rounded at
the ends, truncate and denticulate on the
left side; aquatic ; length 1-560". See
OXYTRICHA.

ASPIDISCINA.

[ 82 ]

ASTASIA.

BIBL. Ehrenb. Infus.; Duj. In/us.-,
Stein, Infusionsthiere &c.

ASPIDISCI'NA, Ehr.— A family of In-
fusoria.

Char. A carapace present in the form of
a transparent flattened shield, projecting
beyond the mouth in front; flexible bristles
on the ventral surface of the body, with
delicate oral cilia.

Ehrenberg describes an alimentary canal,
the inferior orifice of which alone is terminal.
Hence they correspond to Euplotes, with
the excrementitial orifice terminal.

Dujardin places them among his Coccu-

The setae, styles, or cirri serve for climb-
ing, whilst by the cilia the animals are
enabled to swim.

This family should not be retained, but
the single genus of which it is constituted,
Aspidisca, referred to the Euplota.

ASPID'IUM, Schott.— A genus of Aspi-

Fig. 47.

Aspidium trifoliatum.
An indusium covering a sorus.

diese (Polypodiaceous Ferns), in its old
sense including many of our native species,

Fig. 48.

Aspidium trifoliatum.

Side view, cut through perpendicularly.

Magnified 25 diameters.

but now broken up into subdivisions, raised
to the rank of genera.

A. Lonchitis and aculeatum, including loba-
tum and angulare as varieties, are British.

ASPLANCH'NA, Gosse.— A genus of
Rotatoria, of the family Hydatingea.

Char. Foot, intestine, and anus absent ;
eye-spots (1 to 3) and mandibles present ;
sexes

A. Brightwellii (Notommata syrinx, Ehr. ?).

Female : jaws with a single tooth ; eye-
spot single ; tremulous bodies attached to
an extended filament ; aquatic ; length 1-
24". Male : jaws, pharynx, and stomach
absent ; body truncate ; length 1-40".

A. priodonta (PI. 43. fig. 7, female). 3
eye-spots ; tremulous bodies attached to a
tortuous filament; aquatic ; length— female
1-48", male 1-110" ; jaws of female serrated
(7ft).

BIBL. Brightwell, Ann. N. H. ser. 2, ii.
p. 153, pi. 6 ; Dalrymple, Tr. Roy. Soc.
1849, and Ann. N. H. 1849, iii. p. 618 ;
Gosse, Ann. N. H. 1850, vi. p. 18, viii.
p. 197.

ASPLENIE'^E.— A family of Polypo-
diaceous Ferns, with indusiate sori. Ge-
nera :

Asplenium. Sori dorsal or submarginal,
linear or oblong : indusium similar in shape,
straight or curved, single or double, plane
or tumid, bursting along the outer edge.

Allantodia. Sori dorsal, linear-oblong,
attached to the primary veins ; indusium of
the same shape, and entirely enclosing them,
bursting in an irregular line down to the
centre.

Actiniopteris. Sori linear elongate, sub-
marginal; indusium of the same shape,
folded over them, placed one on each side
of the narrow segments of the frond, and
opening towards the midrib. Frond flabel-
late.
•; BIBL. See FERNS.

ASPLE'NIUM, Presl, Spken-iuort.—A.
well-known genus of Asplenieee (Polypodi-
aceous Ferns), containing a number of indi-
genous species.

ASSILI'NA, D'Orb.— A variety ofNum-
mulina (grouped as a subgenus), in which
the alar lobes are reduced to a minimum,
and thereby the faces of the shell are left un-
thickened, except perhaps at their centres ;
and nearly or quite all the whorls are ex-
posed. These shells are the NummuKwK
explanatce of D'Archiac and Haime. Assi-
lina exponent, Sow., sp., is the best type of
this subgenus of Nummulina. It abounds,
with the more perfect type, in the older
Tertiary strata of Switzerland and India.

BIBL. D'Orbigny, Ann. Sc. Nat. vii. 296
(the Modele 88 here referred to, however,
is an Operculina) ; D'Archiac and J. Haime,
Foss. Ann. de llnde-, Parker and Jones,
Ann. N. H. ser. 3, v. 110, and viii. 232.

ASTA'SIA, Ehr.— A genus of Infusoria
of the family Astasisea.

Char. Unattached, no eye-spot. Flagel-

ASTASLEA.

ASTERIGERINA.

liform filament single, arising- suddenly from
the anterior part of the body, or from a
more or less deep notch in it ; oral aperture
very extensile (Kent), leading to a long
oesophagus.

Dujardin forms an unnecessary genus,
Per cinema, to contain those species in
which the filament arises from the gradu-
ally narrowed anterior extremity of the

A. hamatodes, E. (PL 30. fig. 16). Fu-
siform, tail very short j at first green, then
red ; length 1-380".

The flagelliform filament was absent in the
specimens represented in the figure. The
substance of the body was insoluble in cau-
stic potash, even when heated to boiling,
merely becoming swollen. It exhibited nu-
merous vacuoles, which in some of the or-
ganisms were filled with green grains of
chlorophyll. The colour arose from di-
stinct granules of pigment, scattered through
the colourless substance ; when treated with
solution of iodine and then sulphuric acid,
the Astasice became spherical, and were co-
loured blue, bluish green, and purplish blue,
the purple tint apparently indicating the
presence of cellulose. It was, however,
afterwards found that these colours were
produced by the acid alone.

This curious organism colours the water
of ponds &c. blood-red.

A. limpida, D. (PL 30. fig. 17). Fusi-
form, colourless ; length 1-550".

There are other species ; but they are ill-
defined. A. nivalis, Shuttle-worth, found in
red snow, would appear to be an active form
of Protococcus nivalis.

BIBL. See ASTABIJEA; also Shuttleworth,
Bibl de Geneve, Feb. 1840; Kent, In/us.
p. 375.

ASTASWE'A, Ehr.— A family of Flagel-
late Infusoria.

Char. Body of spontaneously variable
form, mostly with one or more flagelliform
filaments, "insoluble in solution of caustic

This family corresponds nearly to the Eu-
glenia of Dujardin, who asserts the existence
of a contractile integument. Form of the
body variable, sometimes becoming sphe-
rical, at others cylindrical, fusiform, &c.,
and exhibiting a head or tail-like process,
or both. The Astasiaea are distinguished
from the Amcebsea by the absence of the
irregular processes sent out by the latter
from all parts of the body ; and by the pre-
sence of a distinct mouth.

The forms included under the family thus
characterized are still very imperfectly un-
derstood ; and it is probable that some of
them, separated generically by Ehrenberg,
are only transitional conditions of others.
Infusoria exactly resembling Astasia hcema-
todes and Euglena viridis occur without the
flagelliform filament; Euglena also occurs in
a resting form, surrounded by a gelatinous
envelope, like Chlamidomonasfindi undergoes
division into 4, 8, 16 or more new indivi-
duals in this state, so as to form irregular,
floating Algoid patches. The green bodies
make their escape from the gelatinous enve-
lopes under certain circumstances, just in
the same way as the zoospores escape from
the cells of the Oonfervoid Algae. This
resting form also exhibits another character,
especially in winter; the gelatinous envelope
acquires a firm, dense, membranous coat over
its periphery, like the resting spores of the
Confervoids, and in some cases this coat is
polygonal and marked with ridges &c. It
is probable that the colour of the species is
not constant, since it seems to depend upon
similar substances to that of the Palmellaceae,
which are known positively to change from
green to red, and vice versa, and even to fade
into an almost colourless state when kept in
the dark. These organisms still require much
careful examination, not of isolated speci-
mens, but by watching their developmental
history constantly for extended periods and
through different seasons. More is said on
this subject under PROTOCOCCUS.

The following Table gives the genera of
Ehrenberg and Dujardin : —

Attached .................................... Colacium, Ehr.

Unattached.

Two eye-spots .................. ......... Distigma, Ehr.

One flagelliform filament.
bneeyerspot.

With a tail-lite process ...... Euglena, Ehr.

Without „ ...... Amblyophis, Ehr.

Two flagelliform filaments.
Both alike.
Animals green, with a red

eye-spot ........................ Chlorogonium, E.

Colourless, no eye-spot ...... Zygoselmi8,Duj.

One anterior, the other trailing
and retractile ..................... Heteronema,J)nj.

Several filaments '

BIBL. Ehrenberg, Inf. ; Dujardin, Infus.;
Morren, RuUfact. d. Eauxj Brux. 1841 ;
Cohn, Protococ. pluv., Nova Acta Ac. L. C.
N. C. xxii. p. 397. (Abstr. Ray Soc., Bot.
1853, p. 352.)

ASTATHE. See PRIMORDIAL UTRICLE.

ASTEKEGERI'NA, D'Orb.— A pseudo-
genus of Foraminifera, comprising species
G 2

ASTERIONELLA.

[ 84 ]

ASTEROPHORA.

of both Rotalia and Discorbina, that have
star-like patterns on one face of the shell.
In some Rotalice an astral arrangement of
subsidiary chamberlets around the umbo is
formed as in Amphistegina ; and in several
Discorbinte the deep radiating sulci around
the umbilicus are roofed over with distinct,
more or less perfect plates of shell.

BIBL. Carpenter, Intr. For. 204, 213.

ASTERIONELLA, Hass — A genus of
Diatomaceae (Cohort Fragilarise).

Distinguished by the inflation of one or
both ends of the frustules, and by the adhe-
rence of their adjacent angles into a stellate
form.

Doubtless the frustules are originally
parallel, forming a straight filament.

A.formosa (PI. 18. fig. 14). Frustules
4-8 ; in the front view somewhat more en-
larged at the attached than the free end.
Aquatic; length 1-384".

A. Ralfsii. Frustules linear ; valves at-
tenuated towards one end, constricted to-
wards the other, which is rounded and capi-
tate. Aquatic ; length 1-555".

A. Bleakeleyii. Frustules linear, enlarged
at the base. Marine ; length 1-454".

2 other species.

BIBL. Hassall, Micr. Exam, of London
Water ; Smith, Br. Diat. ii. 81 ; Greville,
Ann. N. H. 1865, xvi. p. 4 ; Rabenhorst,
Flor. Alg. i. p. 141.

ASTERODIC'TYON, Ehr. (Per. d. Berl.
Akad. 1845). See MONACTINUS.

ASTERODIS'CUS, Johnson.— A genus
of fossil Diatomaceee, allied to Asterolampra
and Aster omphalos ; but distinguished by
one septum dividing halfway from the
centre, and proceeding to two of the com-
partments, the intermediate smooth ray
being smaller than the others. 3 species ;
rays from 5 to 9.

BIBL. Johnson, SittimavCs Jn. 1852, xiii.
p. 33.

ASTEROLAM'PRA, Ehr.— A genus of
fossil Diatomaceas.

Char. Free; circular; central portion
divided by thin septa, which do not reach
the margin, but alternate with rays extend-
ing to the margin, unsupported by septa ;
fossil. Intermediate between Actinocyclus
and Actinoptychus.

A. marylandica (PI. 25. fig. 5). Marginal
rays eight, septa eight ; interstices between
the rays exhibiting elegant curved series of
dots ; diam. 1-180". Found fossil in Mary-
land.

Other species.

BIBL. Ehr. Ber. Berl Ak. 1844, p. 73 ;
Greville (Jfbnflpr.), Mic. Tr. 1860, p. 102,
1862, 41, 1863/227, 1865, 99; Kiitzing, Sp.
Alg. 129.

ASTERO'MA, D.C.— A genus of Sphse-
ronemei (Stylosporous Fungi) growing
upon leaves and stalks, forming very minute,
slightly prominent coloured or black spots,
more or less confluent, seated on more or
less distinct radiating filaments. Fries
separates part of the species under the name
of Actinonema. Species :

A. reticulatum, D.C. JDothidea reticitlata,
Fr., Corda. On decaying leaves of Conval-
laria. Hooker, Br. Pi. ii. part 2. p. 288.

A. ?7/?m,Klotsch. On elm-leaves. Hooker,
Br. Fl. ii. part 2. p. 289.

A. Prunella, Purt. On green leaves of
Pnnwlla vulgaris. Hooker, Br. Fl. ii. part 2.
p. 289.

A. Padi, Grev. On Prunvs Padus.
Hooker, Brit. Fl. ii. pt. 2. p. 289 ; Berkeley,
Ann. N. H. vi. 364, pi. 11. fig. 4.

A. Rosa, Lib. On rose-leaves. Libert,
Tr. Linn. Soc. Paris, 1826 ; Berkeley, Ann.
N. H. vi. p. 364, pi. 11. fig. 5.

A. tabes, Berk. Ann. N. H. vi. 364. pi. 11.
fig. 6.

A. Veronica, Desm. Berkeley, Mag. Zool.
Sf Bot. i. p. 511.

BIBL. Fries, Summa Vcget. Scan. 424.

ASTEROM'PHALOS, Ehr.— A genus of
Diatomacea3.

Resembles Asterolampra, except that two
of the central septa are parallel, and one of
the marginal rays absent or almost oblite-
rated.

The species occur in the Antarctic ocean ;
the diameter of the valves lies between
1-900 and 1-47". They are distinguished
by the number and direction of the central
rays.

A. Darwinii. Central rays five, flexuous.

A. Hookerii (PI. 25. fig. 2). Central rays
six, marginal five, straight.

A. Rossii. Rays six, inflexed.

A. Buchii. Rays six, straight.

A. Beaumontii. Rays seven, inflexed
(PL 18. fig. 15).

A. Humboldtii. Rays eight, straight.

A. Cuvierii. Rays nine, straight.

A. Brookii. Rays ten.

BIBL. Ehr. Ber. d. Berl. Akad. 1844;
Kiitzing, Sp. Alg. 129.

ASTEROPH'ORA, Dittm.— A genus of
Sepedoniei (Hyphomycetous Fungi), com-
posed of minute fibrous plants, growing
parasitically upon dry blackened Agarics^

ASTEROTHRIX.

ATAX.

deriving their name from the angular, some-
what stellate spores ; now shown by Tulasne
to be the conidiiferous state of a species of
Hypomyces. Two British species :

A. agaricoides, Fr. Stipe solid, 1" high,
1'" or more thick, villous, bearing a head,
at first hemispherical, then plane, about 1-2 "
wide, at first covered by a white fugacious
tomentum, with lamellae underneath ; spores
6-angled. On decaying Agarics (A. adustus,
piperatus), in autumn, gregarious. A. lyco-
perdioides, Dittm. Sturm's Deutsch. Fl.

A. ly coper dioides, Fr. Stipe 1" high or
obsolete; head hemispherical or globose,
without lamellae beneath ; spores 5-6-angled.
In similar situations, rather more common.
Agaricus lijcoperdioides, Sow.

BIBL. Hook. Br. Fl. ii. part 2. p. 322;
Sowerby, Fungi, t. 279; Sturm, Deutschl.
Fl. iii. t. 26; Bulliard, Herb. t. 166, 516,
fig. 1 ; Tulasne, Carpologia, iii. p. 54.

AS'TEROTHRIX, Ktz. — An obscure
genus of Algae.

Char. Filaments very minute, indistinctly
jointed, greenish, very rigid, stellately
branched, acutely cuspidate at each end,
floating; A. Pertyana (PL 3. fig. 5).

3 species: freshwater.

BIBL. Kiitzing, Phyc. 6-'ew.p.200; Raben-
horst, Flor. Alg. iii. p. 391 ; Perty, Kleinst.
Lebensf. p. 216.

ASTH'MATOS, Salisb.— A genus of
Cilio-flagellate Infusoria.

Char. Free, rounded, with an anterior
bundle of cilia, and a flagelliform filament.

A. ciliaris (PL 53. fig. 9). In the mucus
of the eyes, nose, and throat, in catarrh and
hay-fever; length 1-1200". Probably the
ciliated epithelium covering the mucous
membranes of these passages.

Kent, Inf. p. 466.

AS'TOMUM, Hampe— A genus of Bru-
chiaceae (Acrocarpous Mosses), including
some of the Phasca of Linnaeus, &c.

A. subulatum, Hucnp.=Phascum subida-
tum, L. (fig. 49).

A. alternifolium, Hmp. = Ph. alternifo-
lium, Dicks, Crypt, (fig. 50). _

A. nitidum, Hmp. =Ph. axiUare, Dicks.

BIBL. Miiller, Syn. Muscor.-, Wilson,
JBryol. Brit. p. 24.

ASTRORHI'ZA, Sandahl.— A relatively
large Rhizopod, related to Lituola. Vary-
ing from sphaeroidal to irregularly star-
shaped, and having sometimes a disk ^ inch
broad, besides radii or digitated branches.
Its test is arenaceous and thick, without
any large aperture, the pseudopodia being

Fig. 49.

Fig. 50.

Astomum subulatum. Astomum alternifolium.
A leaf, showing the oellu- Section of sporange.

lar structure. Magnified 40 diameters.
Magnified 40 diameters.

extruded from between its constituent sand-
grains.

BIBL. Sandahl, Ofvers. Vet.-Akad. For-
handl. 1857, p. 299; Carpenter, Pr. Ray.
Soc. 1869, p. 289.

ASTROSI'GA, Kt.— A genus of Flagel-
late Infusoria. Resembling Uvella, but
flagellum surrounded by a hyaline collar.

A. disjunct a : fresh water.

BIBL. Kent, Inf. p. 341.

ASTROTHE'LIUM, Eschw.— A genus
of Lichenaceous Lichens.

A. parmularia. On young oaks, very
rare.

BIBL. Leighton, Lich.-Flora, p. 499.

ATAX, Duges. — A genus of Arachnida,
of the order Acarina, and family Hydrachnea.

Char. Body ovoid ; a genital fissure bor-
bered by two plates, upon each of which
are three transparent rounded tubercles;
anterior coxae posteriorly in contact in the
median line, wedging the labium between
them anteriorly ; the two groups of posterior
coxae distant; fourth coxa very broad, in
contact with the third throughout its whole
length; palpi with the fourth joint very
long, attenuate, slightly excavated towards
the end to receive the fifth joint in a state
of extreme flexion; fifth joint forming a
pointed claw ; mandibles consisting of a
thick body cut off obliquely like the point
of a pen posteriorly, truncate anteriorly,
and terminated by a large, strong, and
slightly curved claw ; labium oval, concave
and bifid,

Several species, of various brilliant colours.

A. histrionicus (Hydrachna

ATAXOPHRAGMIUM.

L 86 ]

AULACOSIRA.

Herm.) (PL 6. fig. 14). Body dark red, paler
in front of the eyes, a square black spot in
front of them ; dorsally marked with longi-
tudinal converging striae ; five black spots
on the anterior portion of the ventral surface ;
palpi and legs blackish green.

The black spots are produced by the vis-
cera indistinctly visible through the skin.

A. Bonzi is semitransparent, yellowish,
with some brown ; parasitic in the shell of
the freshwater mussel.

Murray states that Arrenurm viridis is
the male of Atax histrionica.

BIBL. Walckenaer, Apteres, iii. (Gervais) ;
Hermann, Mem. Apterol. ; Duges, Ann. d.
Sc. N. 2 se*r. i. ; Koch, Deutschl. Crust., &c. ;
Claparede, Studien an Acariden (Ann. N. H.
1. 1871, 55) ; Murray, JEcon. Entom. 154.

ATAXOPHRAG'MIUM, Reuss. — The
Buliminae with arenaceous shells come un-
der this denomination.

BIBL. Reuse, Sitz. Ak. Wien. xliv. 383.

ATHERO'MA.— Atheromatous deposits
consist of globules of oil of the most varied
sizes, frequently exceedingly minute, mixed
with albuminous matter in the form of
amorphous masses or flakes and molecules,
plates of cholesterine and granules of carbo-
nate of lime.

ATHY'RIUM, Roth.— A subgenus of
Aspkniwn (Polypodiaceous Ferns). To this
belongs the lady-fern, A. Filix-fcemina, for-
merly known as &&Aspidium and a Lastrcea.

AT'OM A, or Astoma, Latr. = TBOMBI-
DIUM, pt.

ATRAC'TIUM.— A supposed genus of
Stilbacei (Hyphomycetous Fungi), charac-
terized by its fusiform elongated spores,
but now believed to be a state of some
Nectria.

BIBL. Tulasne, Carpologia, iii. p. 104.

ATRACTOB'OLUS, Tode. — JFormerly
described as a genus of Nidulariacei (Gaste-
romycetous Fungi), is merely the egg of a
Raphianathus.

ATRACTONE'MA, St. —A genus of
Flagellate Infusoria.

Char. Free, fusiform, flagellum single ;
oral aperture connected with the contractile
vesicle, nucleus central.
A. teres (PI. 53. fig. 8). Fresh water.
BIBL. Kent, Infus. p. 373.
ATRAC'TYLIS, Wright.— A genus of
marine Polypes, of the order Hydroida, and
family Atractylidae.

Char. Polypes naked, borne on a stolon,
erect, funnel-shaped, with a conical probos-

cis, surrounded by a simple whorl of filiform
tentacles.

A. arenosa. Surface sanded. On stones,
and roots of Laminaria.

BIBL. Hincks, Hydr. Polypes, p. 87.
AT'RICHUM, Palis.— A genus of Moss-
es, forming a subdivision of POLYTRI-
CHUM.

BIBL. Wilson, Bryol. Brit. p. 202.
ATRO'PIA (Atropine). See ALKALOIDS.

AT'ROPOS, Leach.— A genus of Hyme-
nopterous Insects, of the family Psocidae
(Termitidae).

Characterized by the long setaceous an-
tennae, which have more than ten joints,
the absence of wings, the eyes of moderate
size, and the three-jointed tarsi.

A. pukatorius (book-mite) is very com-
mon in dried collections of plants, old books,
&c., which form its food. It is about 1-^0"
long, of a dirty-white or yellowish colour ;
head oblong; joints of antennae elegantly
striated transversely ; mandibles horny and
toothed ; abdomen oblong-ovate, depressed ;
posterior femora thickened.

The allied genus Psocus has the head
broad, and the posterior margin of the fore
wings with three or four cells. The species
are found upon old palings, the bark of
trees, &c.

BIBL. Westwood, Entom. Text-book, 368 ;
id. Introdnct. $c., ii. 1 7 & 20.

AT'THEYA, West.— A genus of Diato-
maceae.

Char. Frustules compressed, annulate;-
valves elliptic lanceolate, with a median
longitudinal line ; angles spinous.

A. decora (PI. 51. fig. 39). Druridge
Bay.

BIBL. Micr. Tr. viii. p. 152.

ATTHEYEL'LA, Brady.— A genus of
Copepodous Entomostraca, allied to Can-
thocamptus.

2 species ; fr. water.

BIBL. Brady, Copepoda (Ray Soc.}. ii. 58.

AUGITE. See ROCKS.

AULACODIS'CUS. See EUPODISCUS.

AULACOG'RAPHA, Leighton.— A ge-
nus of Graphideae (Lichenaceous Lichens),
founded on the species Aulacographa (Ope-
grapha) elegans, Sm., distinguished by the
peculiar furrows of the proper margins sur-
rounding the disks of the lirellae. Grows on
the bark of trees.

BIBL. Leighton, Ann. N. H. xiii. p. 389,
pi. 7, 1854 ; Lichen-Fl. 427.

AULACOSI'RA. See MELOSIRA.

AULISCUS.

BACILLUS.

AULIS'CUS, Ehr.— A genus of fossil
Diatomaceae.

Differs from Eupodiscus in the processes
being more solid and less fragile, and in the
markings of the valves consisting of wavy
festooned strife, in some resolvable into
dots, in others not. But the genus seems
unnecessary.

Eupodiscus sculptus (PL 16. fig. 31) would
form a species of Auliscus.

Auliscus pruinosus, PL 18. fig. 60.

BIBL. Ehrenberg, Ber. d. Berl. Ak.-,
Bailey, Smiths. Contrib. 1854; Greville,
(Monogr), Micr. Tr. 1863, p. 36; ibid,
(neiv spec.}, 1863, p. 75; 1864, pp. 82, 88 ;
1865, p. 5 ; 1866, p. 6 ; Rabenhorst, Flor.
Alg. p. 320.

AULOCOM'NIUM, Schwsegr.— A genus
of Mosses. See MNIUM.

AVAN'TURINE.— A mineral composed
of silex, with numerous minute scales of
mica interspersed through its substance, or
traversed in all directions by minute fissures
or cracks, giving it an elegant sparkling or
iridescent appearance.

Artificial Avanturine consists of glass
with numerous minute crystals of metallic
copper distributed through it. These crys-
tals ore mostly in the form of triangular or
hexagonal plates, the angles sometimes cu-
riously prolonged or beaked.

It forms a beautiful microscopic object,

It was originally manufactured at Venice,
and the process kept secret. But MM.
Fremy and Clernandot have shown that it
may be prepared by heating glass with prot-
oxide of copper and iron scale (protoxide
of iron) ; the latter reduces the protoxide
of copper by combining with the oxygen so
as to form the peroxide.

BIBL. Wohler, Chem. Gaz. i. ; Fremy and
Clemandot, /. c. iv.

AVENEL'LA, DalyelL— A genus of In-
fundibulate Polyzoa, of the suborder Cyclo-
stomata, and family Vesiculariidae.

Distinguished by the thread-like, nearly
simple base ; the large, scattered, solitary,
slightly contracted and curved cells ; and
the 20 to 24 tentacles and small gizzard.

The single species, A. DalyeUii (fusca),
brown, occurs matted with foreign matters ;
cells about 1-16" long. On Sertulariae, f rom
deepish water.

BIBL. Dalyell, Anim. of Scotland, ii. 65 ;

Gosse, Mar. Zool. ii. 21 ; Hincks, Poh/z. 526.

m AVICULA'RIA.— A term applied to the

'birds'-head processes of the Polyzoa. See

POLYZOA.

AZOLLA, Kaulf.— A genus of Marsile-
aceae or Rhizocarpese, consisting of a few
species of small floating plants, occurring
in Australia and throughout America. The
mode of reproduction is evidently analogous
to that of Salvinia ; but its development has
not yet been fully examined.

BIBL. R. Brown, Flinders's Voyage, ii.
App. p. 611 ; Meyen, Nova Acta, xviii.
p. 507 ; Griffith, Calcutta Jn. of N. Hist. v.
p. 227 ; Mettenius, Linncea, xx. p. 259, 1847
(Ann. des Sc. Nat. 3 ser. xi. p. 111).

B.

BACILLA'RIA, Gmelin.— A genus of
Diatomaceae.

Char. Frustules bacillif orm, at first united
transversely into a straight tabular series,
subsequently forming oblique series; valves
with a longitudinal row of puncta, and an
excentric keel ; marine.

B. paradoxa (PL 16. fig. 14, and PL 18.
fig. 17). Front view of frustules linear,
rectangular, valves linear-lanceolate ; length
1-220". (a, front view of oblique series of
frustules ; b, valve.)

B. socialis, Greg., and B cursoria, Donk.

BIBL. Kiitz. Sp. Alg. and Bacill. ; Smith,
Brit. Diat. ii. 8; Rabenhorst, Fl. Alg. i.
165.

BACIL'LUS, Cohn.— A genus of Schi-
zomycetous Fungi.

Char. Filaments very minute, straight,
slender, short or of moderate length, rigid
or flexible, moveable or not, joints indis-
tinct ; never found naturally in the Zooglcea-
form.

B. suUilis (PI. 7. fig. 18, PL 1. fig. 19).
Filaments very slender, elongate; joints
single or many, with a cilium at each end ;
movement flexuous, active. In stagnant
waters, &c. It forms Pasteur's butyric fer-
ment, and the hay-bacillus ; length 1-5000"
and upwards.

B. anthracis. Like the last, but general-
ly longer, motionless ; length 1-6000" and
upwards. In the blood and tissues of cattle
and sheep, the horse, &c., producing the
disease termed Anthrax, or splenic malig-
nant fever, the Charbon of the French, the
Milzbrand of the Germans, also the human
malignant pustule, and the wool-sorters'
disease.

B. ulna (PL 7. fig. 20). Filaments join-
ted, thick and rigid, movement rotary and
progressive. Warming describes cilia as in

BACTERIASTRUM. [

Bacterium termo. In infusions, salt and
fresh ; in stale infusions of boiled egg ; length
1-600".

B. ruber. Filaments single, or in twos
and fours, movement very active. In a red
mucilaginous matter on rice.

Other species have been described: B.
malarice (ague-fungus), Klebs; B. viride,
v. Tieghem ; B. leprosus} in leprosy ; and B.
typhi abdominalis.

Amylobacter is sometimes referred to
Bacillus.

Reproduction is stated to occur by fission,
and by the formation of globular or oval
spores developed within the joints ; some of
these form resting-spores. In B. anthracis,
cultivated in the dog, sporanges with 3 to 6
spores are stated to be found. Cohn also
describes globular or elliptical strongly re-
fractive headlets, supposed to be germinated
from gonidia. See SCHIZOMYCETES.

BIBL. That of BACTERIUM.

BACTERIAS'TRUM, Shadb.— A doubt-
ful genus of marine Diatomaceae, character-
ized by the compound cylindrical frustules,
forming a filament, and the discoidal valves
with radiate marginal slender rays.

B. curvatum (PL 18. fig. 18). * Rays en-
tire, arched; B. furcatum, rays straight,
forked ; B. nodulosum, rays simple, straight,
covered with nodules ; B. Walliclm, rays
simple, straight.

BIBL. Shadbolt, Qu. Mic. Jn. ii. 14 ; Ra-
benhorst, Fl. Alg. p. 322 j Lauder. Mic. Tr.
1864, p. 7.

BACTERID'lUM=BACiLLus.

BACTE'RIUM, Ehr.— A genus of Schi-
zomycetous Fungi.

These organisms were formerly arranged
with the Infusoria ; subsequently with the
Algae, with which Davaine, Rabenhorst,
Cohn and Cienkowski still associate them,
on account of the resemblance of form, the
grouping, the mode of multiplication, and
their affinities with the genera Beggiatoa
and Leptothrix.

Char. Cells cylindrical or elliptical, very
minute, single or in twos during division,
rarely four ; motion oscillatory.

Many species have been described. By
repeated subdivision Bacteria are resolved
into a Micrococcus-form (Cienkowski).

B. termo (PI. 7. fig. 17«, and PI. 1. fig.
20). Colourless ; twice to five times as long
as broad, slightly swollen in the middle,
joints one or two ; length 1-1900" - 1-12000":
breadth 1-12000" -1-50000". Occurs in
animal and vegetable infusions ; often be-

J

BACTEIDIUM.

coming surrounded with gelatinous matter
forming masses — the Zoogloea-fonn. Fur-
nished with a ciliurn at each end (Dallinger
and Drysdale, and Warming).

This is the first and true cause of ordinary
putrefaction.

B. catenula (fig. 176). In foetid infusions,
and the excretions of typhoid fever.

B. punctum (fig. c). In animal infusions j
length 1-5000", breadth 1-10000".

B. triloculare (fig. 17c?). Oval, two to
five times as long as broad, with from 3 to
6 joints; length 1-2000" -1-5000".

B. lineola (tig. Vie). Cells straight or
slightly curved, larger than B. termo, single
or in twos ; movement active. In animal
and vegetable infusions, marine and fresh
water. Zooglcea-plasma with dark puncta.
Turns milk sour.

Some coloured species have been descri-
bed : B. xanthium, in cows' milk, colouring
it yellow ; B. syncyanum, in sour milk,
rendering it blue ; B. ceruginosum, in pus,
rendering it blue ; B. brunneum, in brown
decomposing infusions of maize; B. rubescens
and sulphuratum appear to be the same as
Monas vinosa.

Many of the Bacteria may be well pre-
served by simply drying them upon a
slide.

Numerous other organisms are sometimes
included under the term Bacteria, some of
them globular. The subject will be treated
generally under SCHIZOMYCETES. See also
COCCOBACTERIA and MICRO-COCCUS.

BIBL. Ehrenb., In/us. ; Dujardin, Inf. ;
Sanderson, 12th and 13th Privy Council
Repts. ; Cohn, Beitraye, i. and ii. ; Pasteur,
Ann. de Chimie, 1 862, 66 ; Warming, Vi-
densk. Medd. Kjb'benhavn, 1875, 322 j
Lankester, Qu. Mic. Jn. 1873, 408 ; Mag-
nin, Bactcries, 1878; Koch, Cohrfs Beit.
1877, ii. j Davaine, Diet. Encycl., Art. Bac-
terie; Archer, Qu. Mic. Jn. 1878, xviii.
455 ; Ewart (B. anthracis), Proc. Hoy. Soc.
1878; Dallinger, Jn. Mic. Soc. 1878, i. 175
(figs.) ; Cienkowski, Mem. Ac. Pctersb. xxv.
(Qu. Mic. Jw.), 1878, xviii. 456; Roberts,
Phil. Tr. 1874, 466 ; Waldstein, Qu. Mic.
Jn. 1880, xx. 190; Lister, Qu. Mic. Jn.
xiii. 380 ; Livon, Jn. Mic. Soc. 1879, ii. 760
(Bacteria no poison) ; Dowdeswell (Atmo-
spheric), Qu. Mic. Jn. 1878, xviii. 82 ; Klebs,
Zeitschrift, 1879; V. Tieghem, Butt. Soc.
Bot. Fr. (Jn. Mic. Soc. 1880, i. 89) ; Tyn-
dall, Putrefaction fyc., 1881.

BACTRID'IUM, Kunze.— A genus of
Torulacei (Coniomycetous Fungi) ; micro-

BADHAMIA.

BANGIA.

JBactridium can-

didum.

Magnified 200
diameters.

scopic plants of tufted habit, growing upon
decaying wood, old bark, &c. ;
white at first, but coloured Fig. 51.
subsequently by the condensa-
tion of the grumous contents
of the spores. Three species
are recorded as British :

B. Jlavunij Kze. On elm
stumps.

B. Helvellte, B. and Br.
On Peziza testacea.

B. atrovirens, B. On dead
stumps.

BIBL. Berkeley, Brit. Fl. ii. pt. 2. p. 350;
Crypt. Bot. p. 330 ; Kunze, Mycol. Heft i.
pi. 1. fig. 2, pi. 2. figs. 20 and 21 ; Nees,
NovaAeta, ix. pi. 1. fig. 3, pi. 2. fig. 21.

BADHA'MIA, Berk.— A genus of Myxo-
gastres (Gasteromycetous Fungi), consisting
of little variously-coloured sacs growing in
patches on decayed oak-branches, &c. ; allied
to Physarum, but remarkable for the spores,
at first enclosed in a common sac, adhering
in clusters. Filaments of the capillitium
broad.

BIBL. Berk. Linn. Tr. xxi. 152, pi. 19;
Crypt. Bot. p. 338.

B^EOMY'CES, Pers.— A genus of Li-
chenaceous Lichens.

The four species are found on the earth
and stones.

BIBL. Leighton, Lich.-FL, 50.

BAIRDIA, M'Coy. — A marine genus of
Bivalved Entomostraca, belonging to the
Ostracoda and related to the Cypridae.
First known by its valves alone, winch are
subtriangular. Abundant, both recent and
fossil ; found also in the Palaeozoic rocks.

BIBL. M'Coy, Garb. Foss. Ireland (1844),
165 ; Jones, Monog. Tert. Entom. 51 ; G. S.
Brady, Linn. Tr. xxvi. 360 and 388 ; Jones
and KiAby, Q. Jn. Geol S. xxxv. 565

BALANI'NUS, Germ.— A genus of Co-
leoptera, of the family Curculionidse.

B. nucum is well known as depositing its
eggs in nuts, upon which the larva lives, and
from which it escapes, leaving a hole.

The beetle is 1-3" long, with a rostrum
nearly as long as the body. Larva white,
with a brown head and strong jaws.

BIBL. Stephens, Brit. Col. p. 232 ; Boisdu-
val, Ent. Hortic. p. 152 j Calwer, Kaferbuch,
548 (fig.).

BALANTID'IUM, 01. & L.— A genus
of Infusoria, fain. Bursarina.

Like Kondylostoma, but the body dilated
behind and narrowed in front.

B. entozoon. In the human intestines,
and those of frogs.

BIBL. 01. & Lachm. In/us, p. 227.

BALSAM (Canada). The liquid resin of
the Pinus Balsamea. This is the ordinarily
used and best medium for the preservation
of dry transparent objects. The more co-
lourless it is, the better. It should be kept
in a wide-mouthed bottle, covered by a large
cap, fitted by grinding. A piece of iron- wire
should be kept in the bottle, so that the
desired quantity can be easily removed. It
becomes thicker by keeping, but may be
rendered thinner by mixture with oil of tur-
pentine and digestion at a gentle heat, or
with benzole. If too thin, it should be ex-
posed to a gentle heat in a bottle covered
with paper, to exclude dust. See PRESER-
VATION.

BALSA'MIA, Vittadini.— A genus of
Tuberacei (Ascomycetous Fungi), character-
ized by the hollows which are lined by the
fructifying cells not leading to the surface,
and its cylindrical or oblongo-elliptic even
sporidia.

Balsamia platyspora occurs in different
parts of England, and is eagerly scratched
up by squirrels attracted by its strong scent.

BIBL. Tulasne, Fungi Hypogcei; Berk.
Outl. p. 378 ; Cooke, Handbook.

BANA'NA. See MUSA.

BANG'IA, Lyngb. — A genus of Porphy-
rese (Florideous Algae), placed among the
Ulveae by most authors, but stated by M.
Thuret to be Florideous. Species marine,
forming purplish, brownish-green, or red
tufts of filaments, upon rocks and stones or
on the fronds of other Algae, from 1 to 4
inches long, or in B. ciliaris, only half a
line long. Harvey admits five, three of
them, however, as doubtful :

B. fusco-purpurea, Dillw. Brownish
green or purple glossy, several inches long ;
near highwater mark. Phyc. Brit. t. 96 ;
Brit. Algce, t. 25 0 ; Eng. Bot., t. 2055 & 2085.

B. ciliaris, Carm. Forming a minute
pink fringe on Zostera marina.

B. ? ceramicola, Lyngbye. Purplish rose.
On small Algae ; abo'ut 1" long.

B. ? carnea, Dillw. Pale red tufts on
Confervae.

B. ? elegans, Chauv. Minute tufts 1'" or
2'" long, rose-red, parasitic on small Algae,
rare. Harv. Phyc. Brit. t. 246.

See SCHIZOGONIUM.

BIBL. Haryey, Mar. Alga, 1849, 217
(figs.); Berthold, Jn. Mic. Soc. 1881.
i. 97.

BARBULA.

BARK.

BAR'BULA, Hedw.— A genus of Pottia-
ceous Mosses, synonymous with Tortula, and
including some of our commonest mosses,
growing on walls &c.

BIBL. Wilson, Bryol. Brit. p. 134.

BARK.— The outer coat of the trunks
and branches of Dicotyledonous shrubs and
trees, succeeding to the epidermis as the
young shoots become solid and woody. Bark
is a complicated structure, composed of ele-
mentary tissues of various characters ; and
the great differences of appearance which it
presents upon trees which have attained a
certain age, result from the growth and mul-
tiplication of the elementary organs being
subject to very different laws in different
plants. Bark is the collective term applied
to the entire cortical mass outside the
cambium-region of the stem (CAMBIUM).
It contains three distinct regions or forms
of structure; and in young branches the
epidermis, still remaining on the outside,
constitutes a fourth.

If we examine a young shoot of the Maple
(Acer campestre) while still green, by making
transverse and perpendicular-radial sections,
we find the surface to be covered by an epi-
dermis composed of small cells, closely con-
joined at their sides. Under this occur six
or eight strata of thin-walled, colourless
cells, which 'stand vertically over one an-
other, and when mature are extended in
the radial direction of the branch. These
form the cork-substance, suberous layer, or
periderm. Beneath or within these, we find
a layer of thin- walled parenchymatous cells,
filled , with protoplasm and chlorophyll
granules, forming the cellular envelope, cork-
cambium or phellogen. Interposed between
the cellular envelope and the cambium region
occur the liber-bundles (see LIBER), forming
the fibrous layer of the bark. In the bark
of the Maple, the corky substance grows
very fast at first, and soon splits the epider-
mis above it, but after a certain number of
years its growth slackens, so that it seldom
acquires very great thickness, especially as it
is very soft and readily rubbed off; thie cel-
lular layer does not grow fast, merely keep-
ing pace with the enlargement of the stem
which it surrounds. The layers of liber
increase year by year so as to form a very
distinct fibrous layer.

In the Cork-Oak (Quercus Suber), the
bark of which, when young, does not differ
much from that of the Maple, the cellular
layer grows most in the earlier years, and
the epidermis is not destroyed until the third,

fourth, or fifth; then the cork-substance
begins to increase in an important degree
by the multiplication of its cells at the inner
side, bordering on the cellular envelope. New
layers of cork-cells are produced successively,
expanding much in the radial direction.
They are thin-walled and destitute of con-
tents, of squarish form (PL 47. figs. 16 £17),
and soon become dry. The outer layers
being unable to expand sufficiently to allow
the enlargement of the stem,tear irregularly,
and give the surface of the stem a rough and
cracked aspect. On old stems we observe
that the formation of these layers has not
been continuous, but in successive groups or
sets, which causes the appearance of a darker
and more solid structure, composed of tabu-
lar cells, at the points where successive sets
of layers adjoin, just as is the case at the
lines of union of the annual rings of wood in
Dicotyledonous stems. But these lines are
very irregular. The cellular envelope takes
no share in the formation of the cork of this
tree.

In the Birch (Ketula alba), there is a very
decided distinction between the layers of the
cork-substance, namely between the large
thin- walled colourless cells and the denser
tabular cells forming the dark streaks in
the cork. The epidermis is succeeded here
by a periderm composed of tabular cells
with brown contents, corresponding to the
darker parts of common cork ; in stems
of 20 years' growth, the bark presents as
many as fifty lamellae of this substance,
which lamellae are separated from each other
by layers of the lax white cork-cells. The
readiness with which the latter structure
gives way causes the lamellae to peel off in
thin scales ; and these bring away a portion
of the white intermediate structure on both
faces, and thus acquire their peculiar silvery
aspect.

In the Beech (Fagus sylvatica), where the
bark is smooth, even on old trees, the growth
takes place chiefly in the liber-layers, and
the cellular envelope and cork-substance
merely expand to make room for the enlarge-
ment of the stem j the cork-substance is
here a periderm, i. e. composed of the flat
tabular cells, not loose cork tissue. The
Holly, Ivy, and other smooth-barked trees
are analogous to this.

The scaling off' of the bark of the Plane
(Platanus occidentalis) arises from the for-
mation of layers of tabular peridermal cells
between the layers of liber ; the bark out-
side the layers dries and falls away by the

BARLEY.

[ 91 ]

BARTRAMIOEDELE.

tearing of these peridermal layers. Here,
therefore, the periderm is produced from
the cellular envelope.

In the Lirne (Tilia\ the Oak (Q.Bobnr),
and other trees, a similar production of
peridermal layers within the liber takes
place ; but the layers remain in situ for a
long time, and fall away irregularly, often
persisting for a considerable number of
years as rugged, many-layered scales.

In many of the Coniferse (such as the
Scotch Fir and Larch), the peridermal struc-
ture is in like manner developed from the
cellular envelope ; here, however, the cells
are not tabular, but parenchymatous, and
multiply and enlarge so as to form a thick
layer of cork-like tissue, which loses all
relation with the medullary rays. The tur-
pentine-canals and liber-fibres, engaged in
this corky periderm, become disturbed and
displaced by its irregular growth.

In some" plants, such as the Vine, the
Honeysuckle, &c., the bark is always stringy,
which arises from the formation of each
annual layer of liber being followed imme-
diately by the drying-up, and soon by the
destruction, of the layers of the preceding
year, so that no proper periderm of suberous
or cellular layers exists here after the first
year. The same takes place in the third or
fourth year in Clematis.

The scales, plates, and rings of bark
thrown off, form the rhitidome of some
authors.

The inner layers of the bark are especially
distinguished by the presence of laticif erous
canals in those plants in which that tissue
exists ; these are said by Schacht to be in
many cases a modification of the liber-tissue.
Further particulars are given on this head
under LIBER, where also the intimate struc-
ture of the liber will be explained. See also
LENTICELS and CORK.

BIBL. Henfrey, Bot. (Masters); Mohl,
Vermischt. Schrift. 1845, p. 212 ; Hanstein,
JBau d. Baumrinde, Berlin, 1853 ; Schacht,
Pflanzenzelle, p. 237 ; Sanio, Pringsheim's
Jahrb. ii. 39 ; Sachs, Bot. 107.

BARLEY.— One of the important cereal
grains,f urnished by the Hordeum sativum and
its varieties (Monocot. Plants, N. 0. Grami-
nacese). The starch of the albumen of the
seeds has a form somewhat resembling that
of wheat, but it may be distinguished un-
der the microscope (PI. 46. fig. §) ; and the
small starch-grains are more numerous and
smaller than in wheat or rye, and many of
them are in active molecular motion when

immersed in water. (See STARCH.) Pearl-
barley is obtained by a peculiar mode of
grinding, by which the outer coat or shell
of the grain is removed.

BARTRA'ML^, Hedw.— A genus of
Bartramiaceous Mosses, containing several
common species. B. pomiformis, with its
apple-like capsules, is common on dry sandy
banks.

BIBL. Wilson, Bryol. Brit. p. 277.

BARTRAMIA'CE^E.— A tribe of Bar-
tramioidese (operculate Apocarpous Mosses)
containing several genera. British genera :

Conostomum. Calyptra dimidiate. Pe-
ristoine simple; teeth sixteen, lanceolate,
equidistant ; erect when wet or dry, densely
and nodosely tuberculated, with a median
line, connate in pairs at their apices, and
coherent into an oblique closed cone.

Bartramia. Calyptra dimidiate. Peri-
stome either absent, simple, or double. Ex-
ternal, of sixteen lanceolate, smooth, tuber-
culate teeth, with a median line or sometimes

Fig. 52.

Bartramia marchica.

Magnified fragment of peri-

stome.

separating in the
middle, erect when
wetted, incurved
when dry, red. In-
ternal : a mem-
brane with sixteen
folds, produced in-
to sixteen lanceo-
late, keeled, broad
teeth, ultimately
split into two di-
vergent articu-
lated lobes, with
one to three cilia
interposed or none
(fig. 52).

Catascopntm. Calyptra hood-shaped,
smallish. Peristome simple ; teeth sixteen,
lanceolate, very short, truncate-lanceolate,
differing in form, unequal, transversely arti-
culated, with a median line, whitish, rugu-
lose, rigid and suberect. Capsule inclined on
the collum, globose, small, discelioid, shi-
ning-brown, and ultimately growing black,
thick-skinned, almost horny, without an
annulus, smooth.

BARTRAMLD'ULA, Br. and Sch. (Bar-
tramia, Miiller). — A genus of Mosses sepa-
rated from Bartramia by some authors on
account of the smooth capsule and absence
of a peristome.

BIBL. Wilson, Bryol. Brit. p. 276.

BARTRAMIOIDE^E. — A family of
operculated Acrocarpous Mosses, of c£espitose
habit and varying size. Leaves very varied

BARYTA. [

in form, erect or reflexed, with terete nerves ;
cells parenchymatous, and, except in certain
species, furnished with solitary papillae on
the transverse walls on both faces, mostly
square or more or less hexagonal; lax or
loosish, and densely filled with chlorophyll,
or with a persistent primordial utricle, rarely
thickened. Capsule with a long neck, funa-
rioid, pear-shaped or spherical, regular or
asymmetrical, straight or variously inclined,
smooth or grooved, with an operculum
mostly hemispherical or conical, rarely
beaked. This family is divided into two
tribes :

MEESIACEJE. Areolation of the leaf
lax, smooth, often destitute of primordial
utricle (Meesid), or lax and densely papil-
lose (Paludella). Capsule erect, elongated,
with a more or less elongated neck, hence
more or less pear-shaped) smooth, the neck
bearing stomata.

BARTRAMIACE^E. Areolation either lax
and smooth, lax and papillose, dense and
smooth, or dense and papillose. Capsule
erect or inclined, horizontal or pendulous,
regular or asymmetrical, smooth or grooved,
but more or less spherical, devoid of stomata.

BARYTA. — A knowledge of the crystal-
line forms of the salts of baryta is sometimes
useful in determining the presence of this
substance.

Eutyrate of baryta (PI. 10. fig. 23). When
rapidly separating from an aqueous solution,
forms a pearly film upon the surface, con-
sisting ot dense aggregations of very trans-
parent crystalline laminae, not perfectly se-
parable from each other (a). When more
slowly formed, stellate groups of crystals
are produced (6). The individual crystals
are rarely perfect ; and some are so thin and
transparent that their outlines are scarcely
distinguishable.

Hydrofluosilicate of baryta (PI. 10. fig. 24).
Its production is a test for the presence of
baryta. The crystals are scarcely affected
by either nitric or muriatic acid.

Sulphate of baryta (PI. 10. tig. 25). When
rapidly formed, consists of crystalline gra-
nules (a). When more slowly precipitated
from dilute solutions, it consists of very
minute stellate foliaceous crystals, somewhat
resembling those of the ammonio -phosphate
of magnesia (b). See STRONTIA and LIME.

BASALT. See ROCKS.

BASEMENT MEMBRANE, of Ani-
mals.— Is a very thin, transparent, elastic
and structureless membrane, lying between
the cutis and epidermis of the skin, and be-

l ] BASIDIOSPORES.

tween the epithelium and subinucous tissue
of the mucous membranes and their pro-
longations. It is of considerable firmness,
and serves to support the layer or layers of
epidermal or epithelial cells. It is not
always easily separable and demonstrable,
but is perhaps most readily so in the urinary
tubules of the kidneys.

In chemical composition, this membrane
mostly resembles elastic tissue.

BASIDTA. See BASIDIOSPORES.

BASIDIOMYCETES.— A name applied
by Sachs to those Fungi which have naked
spores situated in a distinct hymenium.
See AGARICINI and FUNGI.

BASIDIOSPORES.— The name applied
to the acrogenous spores produced in groups,
mostly of a definite number, more frequently
of four, on the hymenium of many Fungi,
the term basidium (sporophore, Berk.) being
applied to the four-branched cell upon which
they are attached. Basidiospores are pro-
duced both by the Hymenomycetous and
Gasteromycetous Fungi. In the former
they are found upon the external fruit-
bearing surfaces, such as the gills or vertical
plates of Agarics, on the walls of the tubes
of Potyporus, &c. In the Gasteroinycetes

Fig. 53.

Development of the basidiospores of
Hymenangium griseum.

they are produced upon the convoluted hy-
menium which occupies the interior of the

Fig. 54. Fig. 55.

Basidia and basidiospores Basidia and basidiospores
of Melanogaster varie- of Octaviana astero-

gatus. sperma.

Magnified 400 diameters.

Fungus in the earlier stages of growth ; and
when the spores are mature, the hymenium

BAST.

'[ 93 ] BATRACHOSPERMUM.

and the basidia becoming dissolved, the
spores fall loose in the cavity. The basidio-
spores sprout out gradually from the basidia,
becoming soon shut off' by a cross septum ;
and in some cases they finally acquire a
dense and dark-coloured outer coat.

BIBL. Berkeley, Ann. N. H. i. 81, pi. 4
and 5, iv. loo, pi. 5; Le"veille, Ann. Sc. Nat.
2 ser. yiii. 391, pi. 8-11 j Tulasne, Fungi
Hypogai, passim.

BAST or BASS. See LIBEB.

BATARRE'A, Pers.— A singular genus
of Trichogastres (Gasteromycetous Fungi),
characterized by a universal gelatinous volva,
and a hat-shaped receptacle seated on the
top of a tall stem.

B. phalloides is occasionally found in Eng-
land, but only in a very few localities, either
in sand or in the dusty residue in the inside
of hollow trees.

BIBL. Sow. t. 330 ; Berk. Out. p. 290.

BATHYS'IPHON, Sars. — A delicate
thread-like srjicular Foraminifer.

B.jiliformis. In the Bay of Biscay and
the Norwegian fjords ; length 1" and more.

BIBL. Sars, Vidensk. Selsk. Furhandl.
1871, p. 251.

BATONE'US, Kirch.— A doubtful genus
of Phytoptidi-e ; found on the roots of Popu-
lus tremula. See PHYTOPTID.E.

BATRACHOSPER'MEyE.— Afamilyof
Confer void (?) Algaa. Brownish-green or
purplish freshwater plants ; filamentous,
coated with gelatine. The fronds composed
of aggregated longitudinal filaments, bear-
ing at intervak whorls of short, horizontal,
cylindrical or beaded, jointed ramuli. Dioa-
cious. Fructification : ovate spores attached
to the lateral ramuli, which consist of mi-
nute dichotomous filaments. British genera :

Batrachospermum. Lateral whorled ra-
muli beaded ; spores collected in globular
knobs in the whorls.

Thorea. Stems continuous, whorled, ar-
ticulated, sometimes branched, ramuli cy-
lindrical, the spores at their bases.

BIBL. See these genera.

BATRACHOSPER'MUM,Roth.— Age-
nusof Batrachospermeae (Confervoid Algae),
regarded by Thuret and A. Braun as refer-
able to the Florideaa ; consisting of delicate,
branched, filamentous plants of green, yel-
low, red, or purple colour, growing in clear
slowly running fresh water. The branched
axes of the plants of Batrachospermum (fig.
56) consist of rows of large cylindrical cells
applied end to end, and increase in length
by the successive transverse cell-division of

the terminal dome-shaped cell. While the
cells or joints of the axes are still young,
they send oft' a number of radiating pro-
cesses, which soon become cut off" by septa,
so as to constitute distinct cells, and then
elongate and ramify so as to form the
whorls of articulated ramules (fig. 59),
which at length become very dense (fig.
57). From the basal cells of these branches

Fig. 56.

Fig. 57.

Fig. 56. Batrachospermum moniliforme. Natural size.

Fig. 57. A portion of an axis with whorls of branches.
Magnified.

Fig. 58. A tuft of branches with spores in the midst.
More magnified.

Fig. 59. Highly magnified view of a few cells of an axis
with nascent radiating ramules and their descend-
ing cortical cells.

secondary branches grow down perpendicu-
larly over the cell of the main axis imme-
diately below (fig. 59), forming at length a
kind of rind over it. This differs from the
analogous structure in Char a, in the fact that
there branches grow up as well as down
from each articulation of the axis, and meet
halfway. Some of the ramules which grow
out free become fertile, and produce spores
at their extremities, while others grow out
into transparent capillary points.

The spores are produced in large numbers
in each tuft, forming an agglomerated heap
(fig. 58) at each articulation. The branches
of the main axis are produced by lateral
budding of its cells, just above and as it
were in the axils of the smaller whorled

BATRACHOSPERMUM. [ 94 ]

BEANIA.

branches. Braun has found specimens of
B. c&rulescens and B. Suevorum destitute of
the glomerules of spores, but with smaller
hyaline (Antheridial) cells at the ends of
the branches, as in NEMALEON.

According to Bornet and Thuret, tricho-
gynes exist. These consist of a basal cell
(ultimately the cystocarp), communicating
by a narrow neck with the upper portion,
which is not capillary, but expands into an
oval cell, to which the antheridia adhere.
These are single, rounded cells, arising
from the summit of certain peripheral
elongated branches ; each producing a single
spermatozoid.

The specimens frequently change colour
when dried upon paper, becoming usually
much darker. Bory St. Vincent carefully
examined the distinctive characters of this
genus ; and he is followed by Hassall, who,
however, erects several of his varieties into
species. The following forms are given
under Kiitzing's arrangement: —

B. moniliforme, Roth. Vaguely and
greatly branched, colour various (purple, vio-
let, green, seruginous, fuscescent, or nigres-
cent); whorls or nodes moniliform, distinct,
globose, those of the branches confluent.
Dillwyn, Tab. ii. ; Kiitz. Tab. Phyc. iii. pi.
22. HassaU's pulcherrimum, stagnate, and
rubrum are considered to be varieties of
this.

B. giganteum, Desv. Very large, purple
when dry, axes clothed with very long, bi-
furcated branches. Kiitz. Tab. Phyc. iii.
pi. 23. B. confusum, Hass.

B. affine, Kiitz. Tab. Phyc. iii. pi. 24.

B. caerulescens, Bory. ^Eruginous, slen-
der, very much branched, branches flagelli-
form, equal, slender, slightly thickened at
the tips, whorls of the lower and upper
branches confluent, those of the interme-
diate distinct, contiguous, depressed. Kiitz.
Tab. Phyc. iii. pi. 24.

B. vagum, Ag. ^Eruginous, dichoto-
mously branched, equally thick throughout,
whorls all confluent. Kiitz. Tab. Phyc. iii.
pi. 25 ; var. tenuissimum = Conf. atra, Eng.
Bot. pi. 690.

Rabenhorst admits two species, B. moni-
liforme, with nine, and B. vagum, with five
varieties.

BIBL. Bory St. Vincent, Ann. d. Mvseum,
xii. pi. 22, 29; Hassall, Alga, p. 101, and
pis. 13-16 and 63 ; Decaisne, Ann. d. Sc. Nat.
2 s6r. xvii. p. 340, pi. 15, i. ; Braun, Ver-
jimgung, p. 160 ( Ray Soc. 1853, p. 150) ;
Alg. Unicell. Appendix, p. 105; Kiitzing,

Sp. Alg. p. 535, Tab. Phyc. iii. ; Rabenhorst,
Fl. Alg. iii. p. 404; Bornet and Thuret, Ann.
d. Sc. N. 1867. vii. p. 144 j Sachs. Bot. 1874.
293

BDELLA, Latr. (Scirus).— A genus of
Arachnida, of the order Acarina, and family
Bdellea.

Char. Those of the family (see Arach-
nida). Species numerous.

B. longicornis (vulgaris) (PI. 6. fig. 31 a,
b, mandible). Scarlet ; rostrum longer than
the front segment of the body ; eyes 4 ;
length 1-24".

B. ccerulipes (PI. 6. fig. 31 c, mandible).
Rostrum tolerably short and stout ; mandi-
bles thick and obtuse ; eyes 4 j body red-
dish ; legs blue.

B. elaphus (PI. 6. fig. 44). Rostrum in-
flated at base ; carmine-red, with iridescent
shades ; eyes 2, blackish ; a long bristle on
each side.

Other species.

BIBL. Gervais, Walckenaer's Apt. p. 154;
Koch, Deutschl. Ci'ust. $c. ; Duges, Ann. d.
Sc. Nat. i. 21 ; Murray, Econ. Entom. 144.

BDELLEA.— A family of Arachnida, of
the order Acarina.

The members are minute, more or less
soft, variously coloured, and live in damp
places beneath moss, upon the sand of caves,
&c. Palpi geniculate, attached to the sides
of the rostrum, as the antenna? in the Cur-
culionidae. Movements slow. The single
genus,

Bdella, has the characters of the family,
and includes the genera Scirus, Dug., and
Amonia, Koch.

BIBL. Gervais, Walckenaer's Apt. p. 154;
Koch, Deutschl. Crust. $c.

BDELLOIDI'NA, Carter. — A sessile,
arenaceous, Lituolid Foraminifer, with nu-
merous,transverse, successive, sublabyrinthic
chambers.

BIBL. Carter, Ann. N. H. March 1877,
p. 201.

BEAN-FLOUR.— The flour of the com-
mon bean, Faba vulgaris, is used to adulte-
rate wheat-flour; and that of the locust-
bean, Ceratonia siliqua, to adulterate coffee.
See ADULTERATION and STARCH.

BEAN'IA, Johnst. — A genus of Infundi-
bulate Polyzoa, of the suborder Cheilosto-
mata, and family Eucratiidse.

Distinguished by the creeping adherent
branched thread, upon which the sessile
erect scattered cells are placed, each with
two rows of spines on one side.

B. mirabilis. Parasitical on shells and

BEE. [ !

rocks at or within low water-mark, or creep-
ing among the roots of Bugula (CdluLarid)
amcularia. Cells 1-24" long.

BIBL. Johnst. Br. Zooph. x. 371 ; Gosse,
Mar. Zool. ii. 15 ; Busk, Catal. (Brit. Mus.) ;
Hincks, Polyz. 95.

BEE. See APIS.

BEER.— The fermentation by which this
liquid is produced results from the growth
of the yeast-plant, a microscopic Fungus.
See YEAST and FERMENTATION.

When ammonia is added to beer, a preci-
pitate of the ammonio-phosphate of mag-
nesia falls, resembling that subsiding from
urine under the same circumstances (PI. 13.
fig, 3). This, in the sugar-beer as now
made, is almost absent ; and the beer is de-
prived of an important element of nutrition.

BEGGIA'TOA, Trevis.— A genus of Os-
cillatoriaceae (or properly Schizomycetes),
distinguished by the free, rigid, sheathless
fibres, enveloped in mucus, and the white
granular endochromes. Five species : found
in warm mineral and sulphur springs.

BIBL. Rabenhorst, FL Alg. ii. p. 94.

BELBA, Heyden (Damcws, Koch).— A
genus of Arachnida, of the order Acarina
and family Oribatea.

Char. Cephalothorax ribbed; abdomen
separated from the thorax, rounded as if
bulbous ; legs long, geniculate, with one
claw.

The species live on moss, under stones, &c.

B. geniculata. Beneath the bark of the
pear-tree, &c.

BIBL. Walcken. Apteres, iii. (Gervais),
p. 256 ; Koch, Uebers. 8fc. ; Murray, Econ.
Entom. 215.

BENZOIC ACID.— This acid is well
known as occurring naturally in benzoin
and some other resins. It is found in ani-
mal secretions (urine) as a product of the
decomposition of hippuric acid. It is also
a product of the oxidation ofproteine com-
pounds. It is but slightly soluble in cold,
more readily in hot water and in alcohol,
also in ether.

Its crystals belong to the right-rhombic
prismatic system. It is readily sublimed ;
and the crystals thus produced form shining
delicate needles. Wrhen crystallized from a
solution, it usually forms dendritically ar-
ranged superimposed plates, with angles of
90°, sometimes narrow six-sided needles or
prisms; occasionally the angles are trun-
cated, so that the inclination of the edges
amounts to an angle of 135°.

It is not unfrequently obtained from urine

] BIBLARIUM.

when not fresh, in attempts to procure hip-
puric acid. It may be distinguished from
hippuric acid by its much greater solubility
in ether, by its crystallization in thin plates,
and their form (PI. 11. fig. 13).

BERGMEHL.— The German expression
for mountain-flour. A powdery or more or
less coherent mineral, consisting principally
of the siliceous valves of the Diatomaceas.
In some countries it is mixed with articles of
food in times of scarcity. See DIATOMACE^E.

BERKELEY'A, Greville.— A genus of
Diatomaceae (Cohort Naviculese).

Distinguished by the navicular frustules
being immersed in the branches of the gela-
tinous frond, which is rounded at the base.

The valves are exceedingly thin, brittle
and transparent. No markings have been
detected upon them ; but there can scarcely
be a question that they exist.

B.fragilis(?\. 19. fig. 8). Filiform branches
mostly simple, crowded ; valves lanceolate,
obtuse ; length 1-330". British.

Branches about 1-4" in length. Found
upon marine plants and rocks.

B. adriatica. Branches lax, subdivided,
attenuate and flagelliform ; valves narrowly
lanceolate, almost linear, somewhat obtuse ;
length 1-200".

BIBL. Grev. Crypt. Fl. tab. 294; Ralfs,
Ann. N. H. 1845, xvi. p. 110; Kiitzing,
Bacttl., and Sp. Alg. ; Smith, Br. Diat. ii.
67.

BET'ULA,L.— TheBirch-tree(Dicotyle-
donous Plants, N. O. Betulaceae), remarkable
for its peculiar silvery periderm. See BARF.
The bark of B. nigra contains reservoirs filled
with an aromatic oil and also a peculiar resin,
called Birch Camphor, which is used in the
manufacture of Russia leather.

BEY^RICH'IA, M'Coy.— An extinct ge-
nus, belonging probably to the Ostracoda,
very abundant throughout the palaeozoic
rocks, and presenting a great variety in their
small oblong and deeply lobed valves.
Forty-two species are recorded from the
Silurian, two from the Devonian, and seven
from the Carboniferous rocks.

BIBL. Jones, Ann. N. H. 1855, xvi. 81 &
163 ; Mn. Mic. Jn. 1870, 191.

BIBLA'RIUM, Ehr.— A genus of fossil
Diatom acese.

Distinguished from Tetraci/clus by the
frustules being single, which difference pro-
bably depends upon the species only having
been found by Ehrenberg in the fossil state.

Twelve species (Pis. 50. fig. 39; 18. figs.
38-48). Fossil in Siberia and Oregon.

BICELLARIA.

BIGENERINA,

BIBL. Ehrenberg, Ber. d. Berl. Ak.
1844-45, and Ann. N. H. 1848, i. 393 ; Kiit-
zing, Sp. Alg. ; Smith, Br. Diat. ii. 37.

BICELLA'RIA, De BL— A genus of In-
fundibulate Polyzoa, of the suborder Chei-
lostomata, and family Bicellariidae.

B. ciliata ( Cellularia ciliata, Johnst.) (PI.
41. figs. 5 a and 5 6), is parasitical upon
Algae, Polypi, &c. within low- water mark j
spines about eleven.

An elegant microscopic object.

B. Alder i; spines six.

BIBL. See BICELLABHD^!.

BICELLARIIDAE (Celhdaria, Johnst.
in part). — A family of Infundibulate Poly-
zoa, of the suborder Cheilostomata.

Distinguished by the erect plant-like
polypidom being dichotomously divided into
narrow ligulate branches in two or more
rows; the absence of whips (vibracula); and
the avicularia when present being stalked
and jointed. Genera (British) :

Bicellaria. Cells top-shaped, distinct,
armed with spines ; orifice looking upward.

Bugula. Cells elliptical, closely con-
tiguous ; orifice very large ; margin simple,
not thickened (avicularia frequently red or
blue).

BIBL. Johnston, Brit. Zooph. ; Busk,
Cat. (Brit. Mus.) ; Hincks, Polyz. 67.

BICHRO'MATE OF POTASH. See
POTASH.

BICOSCE'CA, Clark.— A genus of
Flagellate Infusoria.

Char. Solitary, two flagella, 1 long and
1 short; contained in a stalked horny
lorica.

B. lacmtris (PI. 53. fig. 10). Pond-water,
common.

B. gracilipes. Stalk long ; marine.

BIBL. Kent, Inf. p. 274.

BIDDULPHTA, Gray.— A genus of Dia-
tomaceae.

Char. Frustules compressed, quadrilateral,
connected with each other by the angles ;
filaments attached by a stipes ; angles of the
frustules equal and produced ; valves covered
with depressions (visible by direct light),
giving them a cellular appearance ; centre
of valves with spines ; marine.

This genus resembles Isthmia and Amphi-
tetras in the general appearance of the frus-
tules and valves. But it differs from the
former in the angles being alike, and from
the latter in the compressed side view of
the frustules. Frustules often with rounded
transverse elevations, between which are
costae or shallow vittae. Those in which

the angles are more prolonged and acute,
and the markings indistinct, are retained by
Kutzing in the genus Odontella, Ag. (Den-
ticella, Ehr. in part).

B. pulchella, Ehr. (B. tri-t quinque-,
and sepfemlocularis, Kiitz.) (PI. 16. fig. !•">).
Costae 3-7, central one with two or three
short spines ; produced angles rounded ;
markings coarse ; length 1-400 to 1-200".

B. awnta,Bre-b. (PI. 19. fig. 9). Markings
indistinct ; costaB none ; angles horn-like ;
spines two or three, central; length 1-800".

B. rhombus, Smith (Zygoceras rh.
Ehr. ?) (PI. 19. fig. 13, Ehr. ; PI. 50. fig.
16, Smith). Markings indistinct; costas
none ; spines near the hoop ; angles horn-
like; length 1-60 to 1-260".

B. Baileyi, Sm. Markings indistinct;
costaa none ; angles horn-like ; sides of frus-
tules with two slight elevations, each with
one or two long spines ; length 1-250".

B. turgida (Cerataulus turgidm, Ehr.).
Markings faint ; costae none ; angles cylin-
drical, truncate ; frustules with a row of
short and two large submedian spines on
each side ; length 1-240".

B. Regina. Sides of frustules each with
three rounded median elevations ; spines
none ; angles rounded, with distinct mark-
ings ; length 1-220".

Several other species, but not British.

BIBL. Kiitzing, Bacill. and Sp. A1g.\
Ehrenb. Ber. de Berl. Ak. 1843 & 1844;
Ralfs, Ann. N. H. 1843, xii. 273 ; Smith,
Br. Diat. ii. 47 ; GreviUe, Micr. Tr. 1864,
pp. 9, 85 ; 1865, pp. 6, 19, 49 ; 1866, pp. 6,
81 ; Rabenhorst, Fl.Alg. i. p. 310; Pritchard,
Infm. p. 847.

BIFORI'NES.— Under this name Turpin
described certain cells occurring in the septa
of the air-chambers of the leaves of the Ara-
ceae, characterized especially by the presence
of a large bundle of raphides. They contain
a thick fluid ; and when they are placed in
water, endosrnose causes them to burst and
discharge the crystals. See RAPHIDES.

BIBL. Turpin, Ann. Sc. Nat. 2 se*r. vi.
p. 5, pi. 1-5.

BIGENERI'NA, D'Orb.— One of the
numerous modifications of the Textulaiian
type : instead of continuing to form bilateral
alternate (Enallostegian) chambers, it ad-
vances in growth with a straight single
(Stichostegian) series; and the aperture
becomes central, terminal, and rounded, in-
stead of being a transverse arch low down
on the septal face. If the aperture be
excentric, we have the Gemmulina of D'Or-

BIGNONIACE^E. [

bigny. B. agglutinans (PL 23. fig. 50) is an
elongate and coarse-shelled variety of JB.
nodosaria. Common in many seas, and in
the fossil state.

BIBL. D'Orbigny, For. Foss. Vien. 237 ;
Carpenter. Introd. For. 191.

BIGNONIACE^E (Dicotyledons).— The
wings of the seeds of this family afford very
beautiful objects. They are either thin
membranes composed of a layer of lignified
cells ; or, as in the Oatalpas, the wing con-
sists of a fringe of hairs.

BILE.-^Three colouring - matters have
been obtained from the bile, viz. cholepyr-
rhine, biliverdine, and bilifulvine. These
were formerly regarded as distinct ; but
later researches have tended to show that
they are modifications of the same pigment.

Cholepyrrhine orbilirubine, the colouring-
matter in its ordinary state, is characterized
by the series of tints through which it
passes when treated with nitric acid,
especially if this contain nitrous acid;
becoming first brownish, then green, bluish,
violet, red, and finally yellow. It is some-
times found in bile and the liver-cells in the
form of yellow seniicrystalline grains ; also
it enters into the composition of biliary
calculi.

Biliverdine is found in the bile, but not in
gall-stones ; it is formed from bilirubine by
oxidation. It is most abundant in the bile
of the Herbivora.

BUiprasine is brown, becoming green with
acids ; it occurs in decomposing bile.

Bilifulvine is also sometimes found in bile
which has been retained in the gall-bladder.
The bile then appears thick and dark brown,
and exhibits small dark grains ; the crystals
are found in these grains. They form
longish, very fine needles, of a reddish-yel-
low colour, either single or several combined.
When aggregated, they sometimes resemble
the crystals of urate of soda, and are often
curved and twisted. Caustic potash dis-
solves them tolerably readily. Acetic acid
produces no change in them. Nitric acid
has but little effect upon them, unless the
action is very intense, when they are decom-
posed. Virchow notices the occurrence of
these crystals upon the walls of the cysts
of Echinococci in the liver, where we have
also found them, and in the liquid contents
of the cysts. In this instance, two kinds
of crystals were met with (PL 13. fig. 15) :
some of these were rhombs (6), others were
twisted and elegantly curved bundles of nee-
dles («)• When first examined, they were

r ] BINOCULAR.

yellowish-red ; but after remaining a day or
two in the liquid of the cysts, they became
almost perfectly yellow. "When mounted in
balsam, the rhombs remained unaltered,
whilst the long filamentous groups of nee-
dles lost all colour, leaving a barely dis-
tinguishable transparent skeleton. Both
kinds were insoluble in acetic acid, but
soluble in potash with a yellow colour.

In morbid bile, crystals of cholesterine,
globules of fat, and small bundles of needles
of margarine are also occasionally found.

See HJEMATOIDINE.

BIBL. Gmelin's Handb. d. Chem. vii. &
viii. ; Virchow, An. d. Pharm. 1851 (Chem.
Gaz. x.) ; Karsten, De hep. et bile Crustac.
et Mollusc, j Frey, Histol &c. 1876, p. 551 j
Stadeler, Pogg. Annal. cxxxii. p. 323.

BILHARZIA. See DISTOMA.

BILIFULVINE. See BILE.

BILOCULI'NA, D'Orb— One of the
Milioline Foraminifera, in which each suc-
cessive segment embraces more or less com-
pletely the preceding segments, on alter-
nate sides, so that only two chambers of
the shell are visible externally. It varies
much in form and size ; the varieties are
very common, recent and fossil, and have
numerous names : the largest has been found
at 650 fathoms in the North Atlantic (Car-
penter). B. ringens (PL 23. fig. 3) is taken
as the type.

BIBL. D'Orbigny, For. Foss. Vien. 261 ;
Williamson, Brit. For. 78; Carpenter,
Intr. For. 75, 78.

BIME'RIA, T. S. Wright.— A genus of
Hydroid Zoophytes, family Atractylidae.

The body and lower part of the tentacles
enveloped by an opaque brown membrane.

JB. vestita. Attached to zoophytes and
sea-weeds.

BIBL. Hincks, Hydroid Zoophytes, p. 103.

BINOCULAR MICROSCOPE.— This
has been alluded to at p. xiv of the Intro-
duction. We have no space for the figures
requisite to illustrate descriptions of the
three principal forms of binocular micro-
scope; hence we must be satisfied with
referring to the works in which they will
be found. In the examination of new
structures, no reliance should be placed upon
the appearances presented by objects under
binocular vision, unless controlled by the
means pointed out in the second part of the
Introduction.

The three principal forms of binocular
construction are those of Wenham, Holmes,
and Stephenson,

B10MYXA. [

Tolles has invented a binocular eye-piece
(Beale, How #<?., p. 15, fig.) ; and Abbe
another : Jn. Mic. Soc. 1881, i. p. 298 (fig.).

BIBL. Wenham, Micr. Tr. 1860, p. 154,
1861, p. 15, 1866, p. 103; Qu. Mic. Jn.
1861, p. 109 ; Holmes, M. M. Jn. 1869, iii.
p. 274 ; Stephenson, M. M. Jn. 1870, iv.
p. 61 ; Frey, D. Mikr. 1881 ; Carpenter,
The Microsc. 1881.

BI'OLITE. See ROCKS.

BIOMYX'A, Leid.— A genus of Rhizo-
poda.

B. vagans. Resembles the pseudo-
podia of a Gromia, separated from the body.
Fr. water.

BIBL. Leidy, Proc. Phil. Acad. 1875,
(M. M. Jn. xiV. p. 88).

BIS'PORA, Corda.— A genus of Fig.
Torulacei (Coniomycetous Fungi), 60.
characterized by its uniseptate
spores forming; simple and solitary
bead-like chains at the apices of
short, slender, erect filaments, des-
titute of septa, arising from a creep-
ing mycelium. It was separated
from Torula by Corda on account
of the double character of the spores.
According to Fresenius, the chains
of spores are pedicellate as above
described, and the growth of the
chains appears to take place by
division of the terminal cell or spore.

B. monilioides, Corda, of which
fig. 60 represents the chains of
spores without the pedicels, is Bri- ^PJ?*
tish (Torula auct.). On sticks. iHes.

BIBL. Corda, Ic. Fung. vol. i. Magnified
pi. 2. fig. 143 ; Fresenius, Beitr. z. 200 diam,
Mycologie, Heft 2. p. 27, pi. 6. figs. 46-54 ;
Greville, t. 255.

BITARTRATE OF POTASH. See
POTASH.

BLASIA, Micheli. — A genus of Pelliese
(Hepaticae). The British species, B. pu-
silla, L., occurs on moist heaths, not uncom-
monly in the mountainous parts of England,
Scotland, and Ireland. In addition to the
antheridia and pistillidia, and the sporanges
developed from the latter, this plant produces
gemma of two kinds. One kind is formed
in receptacles hollowed out of the nerve,
furnished with a long tubular beak, whence
the gemmae escape when mature. The se-
cond kind is described as black spherical
masses of granular or pulpy substance, and
occur within the epidermis on the under side
of the frond, often covered by the scales.

BIBL. Hooker, Brit. Jtmgermanniat t.

Fig. 61.

* ] BLATTA.

82-84 ; Eng. Bot. t. 1328; Brit. Fl. ii. part
1. 130; Sachs, Bot. p. 347.

BLASTOT'RICHUM, Corda.— A sup-
posed genus of Dematiei (Hyphomycetous
Fungi), of curious habit, growing in and out
of water upon aquatic plants. B. confer-
voides, Corda (fig. 61), forms felted tufts of
an agreeable rose-
colour upon living
and dead parts of
aquatic jEtiphor-
bice, in autumn.
The filaments are
very much branch-
ed, the branchlets
dichotomous and
subulate ; the
spores rose-colour-
ed, containing a
gelatinous nucleus
within. The spores —

are irregularly di- Blastotrichum confcrvoides.
vided; and Some Fragment of fertile filament.

remain imperfect; Unified 200 diameters,
but both these and the perfectly septate
reproduce _ the plant when sown. The
ft. rin occurring above the surface of the
water is "of bloser habit than the submerged,
in which the filaments are longer and more
lax.

Berkeley is of opinion that this plant is
only a state of some Dactylium, perhaps
D. (TRICHOTHECIUM) roseum.

BIBL. Corda, Icones Fung. ii. p. 10
pi. 0 fig. 50; Berkeley, Crypt. Bot. p 302.

BLAT'TA. — A genus of Orthopterous
Insects, of the family Blattidse.

Blatta orienta'lis is the common house
blackbeetle or cockroach. The head and
the various organs of the mouth are figured
in PI. 33. fig. 1, the upper and front view ;
fig. 2 the under view; fig. 22 the parts of
the mouth separate.

Head oval, and .concealed beneath the
large plate of the prothorax. Antenna
(fig. 1 a, broken off) very long, setaceous,
pubescent, and with very numerous joints;
they are inserted close to the inner margins
of the eyes ; basal joint stout and subovate,
second and third squarish, larger than any
of the following, which are ring-shaped
towards the base of the antennae, become
square (in the side view) at the middle, and
oblong at the apex. Labnim (fig. 1 e, fig. 22
lower part of a) exserted, entire, roundish,
truncated at the base. Mandibles (fig. 22 b)
short, stout, toothed at the tip and on the
inner margin; basal portion of the inner

BLEOHNE^E. [

margin membranous, forming a little lobe.
Maxilla (figs. 1 & 2 ff, 22 c) bilobed ; inner
lobe (lacinia, fig. 22 cf) dilated and ciliated
on the inner margin, acute, curved inwards
at the apex so as to form a tooth ; outer
lobe (galea, fig. 22 c *) longer, thick, rounded
and naked ; maxillary palpi (figs. 1 & 2 h)
elongated, rough with short hairs, 4-jointed,
the last joint somewhat hatchet-shaped.
Labium (fig. 22 e) elongated, bifid, with
two more slender inner lobes ; labial palpi
(fig. 2 K) pubescent, 3- jointed, last joint
truncated obliquely. Mentum (fig. 2 /) short,
convex at the base. Eyes (fig. 1 c) kidney-
shaped.

Thorax semicircular, the base convex;
elytra coriaceous, one overlapping the other,
and with numerous nerves. Wings large,
folded longitudinally, with numerous nerves.
Females apterous. Abdomen flat, oval,
and terminated by two short, conical, com-
pressed, jointed appendages in both sexes;
besides which, in the male, there are two
slender, external, not-jointed appendages or
styles, also an elongated intermediate one.
Legs long and compressed ; coxae elongated
and stout; femora stout with a series of
spines beneath; tibiae clothed with very
strong movable spines ; tarsi 5-jointed,
three basal joints gradually diminishing in
length ; claws curved and acute.

An Anuzba and some Bursarina are para-
sitic in the intestines of Blatta.

See INSECTS.

BIBL. Westwood, Introd. #c.; Kirby,
Brit. Entom. i. 12.

BLECH'NEJE.— A family of Polypo-
diaceous Ferns.

Char. Sori linear or oblong, dorsal, paral-
lel with the midrib and edge of the seg-
ments, not close to the latter. Involucre of
the same shape as the sorus, superior,
opening towards the midrib. Gen. :

Blechmim. Sori linear, continuous or
nearly so, parallel with and contiguous to
the midrib.

Sadleria. Sori in a continuous line close
to the midrib on both sides, placed on an
elevated receptacle. Indusium narrow, sub-
coriaceous, at first wrapped over the sorus,
then spreading.

Woodwardia. Sori sunk in cavities in
the frond, in single rows parallel with and
contiguous to the midribs of the pinnae and
pinnules. Indusium subcoriaceous, closing
over the cavity like a lid.

Doodia. Sori oblong or slightly curved,
in one or more rows parallel with and be-

> ] BLIGHT.

tween the midribs and the margins of tho
pinnae. Indusium membranous.

BLECH'NUM, Linn.— A genus of Ferns.
Bl. Spicant, With., is the Hard Fern, also
called sometimes Bl. boreale, but properly
LOMARIA Spicant.

The species are tolerably numerous, closely
resembling each other, and diffused widely
throughout Tropical and South Temperate
regions.

BIBL. Hooker & Baker, Syn. Fil. 183.

BLEPHAEIS'MA, Perty, = PLAGIO-

TOMA, pt.

BLIGHT. — This word is used in common
language in an exceedingly loose and unde-
fined way, bein°f applied to almost every
cause of disease in plants, as well as to the
diseases themselves, which are variously ex-
plained by agencies of meteorological con-
ditions, parasitic plants and insects, opera-
ting singly or in combination. Blight is,
indeed, ' in the air ' in many cases, since a
frequent source of disease in vegetation is
sudden change of temperature or hygro-
scopic condition of the atmosphere, deran-
ging the processes of evaporation and respi-
ration in the tender, actively developing
portions of the foliage or inflorescence of
plants. It is also often < in the air ' in an-
other sense, but much less specially than is
commonly supposed : the plagues of para-
sitic fungi and insects which sometimes
cause such devastation, seem undoubtedly
to arise immediately from the transport of
the microscopic reproductive bodies, spores
and the like, through the air ; but the pe-
culiar atmospheric condition often observed
as accompanying the sudden irruption of
large masses of such i blights,' are only col-
laterally connected with the development of
these bodies ; the warm overcast weather,
almost proverbially designated as the cause
or the herald of blights, is merely an index
of a condition of the atmosphere especially
favourable to the rapid multiplication of the
Fungi and Insecta which are seen to increase
so rapidly at such times ; and the germs of
these must be already present, through other
causes, for the production of the phenomena
under such circumstances.

Only a few of the animal blights need be
referred to here, such as the plant-lice, the
most familiar form of ' blight* in cultivated
plants (see APHID.E) ; the ' pepper-corn ' or
* ear-cockle ' of wheat, Anguillula tritid (see
ANGUILLTTLA) ; the wheat-midge (CECI-
DOMYIA); the vine-pest (PHYLLOXERA) ; the
turnip-fly (HALTICA); the PHYTOPTID^;

H2

BLIGHT.

[ 100 ]

BLOOD.

and the species of Cynips and allied genera,
which produce galls and similar excrescences
by the irritation of the vegetable tissue, re-
sulting from their presence.

Many caterpillars of moths and butterflies
are exceedingly destructive, and form a kind
of blight ; but these scarcely come within our
province.

The vegetable blights, the parasitic Fungi
growing upon living specimens of the higher
plants, and displaying themselves either as
the cause or the accompaniment of some
disease and disorganization, have of late
years become objects of most earnest atten-
tion, on account both of the enormous da-
mage which the diseases have caused to
)lants of high importance to man,

and also of the many curious facts in their
history which have 'been brought to light.
The Potato blight and the Vine disease of
recent years have incited renewed efforts to
elucidate the history of these productions,
as yet, however, imperfectly made out. The
old notion, that these products were the
result of skin-diseases or exanthemata of
plants, is now discarded, especially as many
of them have been grown artificially from
their spores.

The general history of the conditions of
their occurrence, and a summary of the
investigations into their history, are given
under the head of PARASITIC IUNGU. The
particular history of the more remarkable
genera will be found under the heads in-
dicated by the capitals in the following
paragraphs.

Corn-blights consist chiefly of mildew
(PUCCINIA), rust or red-robin (UREDO, TRI-
CHOBASIS), smut, bunt, or brand (TILLETIA,

USTILAGO, POLYCYSTIS), 61'ffot (CORDI-

CEPS), &c. CYSTOPUS ( Uredo) attacks Cru-
ciferous plants. Mildews of pease, peaches,
hops, and many other cultivated plants are
produced by species of ERYSIPHE. OIDIUM
is a common mildew, and is known in many
cases to be only an earlier condition of
Erysiphe. BOTRYTIS is another common
mildew. yEciDiUM forms a kind of rust,
as is the case with the allied RCESTELIA,
infecting pear-trees. See also UROMYCES,
POLYCYSTIS, COLEOSPORIUM, PROTOMY-
CES, EPITEA, PHRAGMIDIUM,FUSISPORITJM,
TORULA, PERIDERMIUM, SCLEROTIUM, SPI-
LOCJEA, SPH^ERIA.

BIBL. De Bary, Brandpilze, Berlin, 1853,
chap. 3. p. 102 ; Berkeley, Tr. Hort. Soc.,
Gardeners Chron., passim; A. Braun,
Krankheiten der Pflanzen, Berlin, 1854 ( Qu.

Mic. Jn., July 1854) ; Sidney, Blights of the
Wheat, Rel. Tract Soc.; art. BtigU, in
Branded Diet., the Penny Cyclop. ; Libr. of
Entertaining Knowledge ; Boisduval, Entom.
Horticole ; Hallier, Phytopatholoyie.

BLINDIA, Br. and Sch.— A genus of Di-
cranaceous Mosses, including some Weissia
and Gymnostoma of authors.

BIBL. Wilson, Bryol. Brit. p. 67.

BLOOD.— This animal fluid, with the
general appearance of which in the higher
animals every one is so familiar, is no less
difficult in its microscopic study, than it is
complex in its chemical composition. In
man and mammalia, birds, reptiles and fishes,
it is a viscid liquid of a red colour. In those
of the lower classes in which it exists, it is
mostly colourless, sometimes, however, red,
bluish, purplish, greenish or milky.

When examined under the microscope
the blood is found to consist of a liquid por-
tion, containing in suspension a large num-
ber of minute corpuscles, which are known
commonly as the globules or corpuscles of
the blood.

In the Mammalia, Birds, Reptiles, Am-
phibia, and Fishes generally, the liquid por-
tion, or liquor sangninis, is nearly colourless,
or of a pale yellow tinge ; and the corpuscles
are of two kinds, one of a red colour when
viewed in mass, but pale reddish yellow when
seen singly or separately, and to these the
red colour of the blood is owing ; the others
consist of perfectly colourless bodies.

* The red corpuscles are far more numerous
than the colourless ones, about 500 to 1, and
consist of delicate membranous colourless
cells enclosing a red liquid. In the Mam-
malia they assume the form of circular flat-
tened disks or discoidal cells, the sides of
which are impressed or hollowed out, so as
to make them resemble doubly concave
lenses, with rounded margins (PI. 49. figs.
21, 22 & 23) ; in the Camel tribe, however,
they are elliptical and doubly convex. In
Birds (figs. 24 & 25), Fishes (figs. 26 & 27),
Amphibia and Reptiles (figs. 28, 29 & 30),
they are elliptical and flattened, the form of
the sides varying : thus, in Birds and Fishes
they are convex, excepting the Cyclostomes
or lamprey Order among the latter, in which
they are circular, flattened and slightly con-
cave, only differing from those of man in
being somewhat larger; and in the Lepto-
cardea — Amphioxus lanceolatus, the lancelet,
there are no blood-corpuscles.

In the Amphibia and Reptiles, in which they
are elliptical, very large, and comparatively

BLOOD.

[ 101 ]

BLOOD.

thin, the surfaces of the corpuscles are rather
concave than convex, the nucleus projecting
somewhat laterally.

The red corpuscles of the Mammalia are
not furnished with a nucleus, whilst in
Birds, Fishes, and Keptiles a distinct nu-
cleus exists ; this is usually oval, but some-
times rounded in the latter.

The colourless corpuscles of the Vertebrata
(figs. 21-30 b), or the lymph-corpuscles, or
the blood-leucocytes as they are sometimes
called, are spherical, of a granular appear-
ance, highly refractive, and specifically
lighter than the coloured corpuscles. They
consist of a cell-wall containing numerous
larger or smaller granules and molecules,
with one or more nuclei. Acetic acid dis-
solves the granules, and brings the nuclei to
view. The cell- wall is often undistinguish-
able, unless water be added to the corpuscles,
which being imbibed, separates it from the
contents. When blood is kept at a mode-
rate heat, these corpuscles exhibit various
Amoeba-like processes, crawl over the slide,
and even take up particles of foreign sub-
stances, as vermilion, carmine, &c.

The blood of the Invertebrata has not
been so thoroughly examined. In many of
them there are two circulating liquids — one
coloured, and sometimes containing hsema-
tine, but no corpuscles ; the other colourless,
and containing rounded or irregular granular
colourless nucleated corpuscles (figs. 31-35),
much resembling the colourless corpuscles
of the Vertebrata, but remarkably prone to
shoot out processes like the Amoebae.

The sizes of the coloured corpuscles of
many vertebrate animals are given in the
subjoined list, nearly all the measurements
being those of Gulliver. It may be re-
marked that, whilst the largest coloured
corpuscles occur in the Reptiles, the small-
est are found in the Mammalia, and that
the size of the corpuscles is in general
proportional to the size of the animal, in
animals of the same order, but not in those
of different orders. Thus, in the larger
Ruminants and Rodents the corpuscles are
larger than in the smaller ones, whilst the
smallest British mammal, the Harvest-
mouse, has corpuscles as large as those of
the Horse ; and in the common mouse they
are larger than in the Horse or Ox.

MAMMALIA.

Bimana. Man, 1-3200 to 1-3500".
Quadrumana. Chimpanzee (Simia Tro-
glodytes}, 1-3412; Monkey (Cercopithecus

mono), 1-3468 ; Monkey, mean of eight
other species, 1-3450 ; Lemur, mean of four
species, 1-4077.

Cheiroptera. Bat (Vespertilio murinus),
1-4175 ; Bat ( Vespertilio pipistrellus), 1-4324.

Insectivora. Hedgehog (Erinaceus euro-
pceus), 1-4085; Mole ( Talpa europcea), 1-4747.

Carnivora. Badger (Meles vulgaris),
1-3940; Bear, mean of five species, 1-3708;
Dog (Canis familiaris), 1-3542 ; Fox (Canis
Vulpes), 1-4117; Lion (Felis Leo\ 1-4322;
Seal (Phoca vitulina}, 1-3281.

Cetacea. Dolphin (Delphinus Phocand),
1-3829; Whale (Balana Mysticetus), 1-4000 ;
Whale (Batena Boops), 1-3099 ; Manatee
(Manatus), 1-2400.

Pachydermata. Elephant (Elephas inrfi-
cus), 1-2745 ; Horse (Equus caballus), 1-4706 ;
Pig (Sus Scrofa), 1-4230 ; Rhinoceros indi-
cus, 1-3765.

Ruminantia. Camel ( Camelus bactrianus),
length 1-3123; breadth 1-5876; Dromedary
(Camelus dromedarius), 1. 1-3254, b. 1-5921 ;
Goat (Capra hircus), 1-6366; Musk (Mos-
chus javanicus), 1-12325 ; Stag (Cervus ela-
phus), 1-4324; Ox (Bos Taurus), 1-4267:
Sheep (Ovis Aries), 1-5300.

Edentata. Armadillo (Dasypus sex-cinc-
tus}, 1-3457 ; Sloth (Unau, Bradywus didac-
tylus\ 1-2865.

Rodentia. Guineapig (Cavia cobaya\
1-3538; Mouse (Mus musculus), 1-3814;
Rabbit (Lepus cuniculus), 1-3607 ; Rat (Mus
Rattus), 1-3754.

Marsupialia. Kangaroo (Macropus), mean
of three species, 1-3460.

Monotremata. Platypus, duck-billed (Or-
nithorhynchus paradoxus), 1-3000.

Birds. Chaffinch (Fringilla ccelebs), length
1-2253, breadth 1-4133; Cuckoo (Cuculus
canorus), 1.1-2028, b. 1-3600: Ezgle(Aquila),
mean of four species, 1. 1-1640, b. 1-3651 ;
~Fow\(Gallus domesticus), 1.1-2102, b.1-3466;
Gull(Mew-,Z«rwscemws), 1. l-1973,b.l-3839;
Humming-bird (Trochilus), 1. 1-2666; b.
1-4000; Ostrich (Struthio camelus\ 1.
1-1649, b. 1-3000 ; Owl (Strix flammed). 1.
1-1882, b. 1-3740 ; Parrot (Psittacus), mean
of twelve species, 1. 1-2042, b. 1-3724 ; Pi-
geon (Columba), mean of sixteen species,
1. 1-2135, b. 1-3679; Sparrow (Fringilla do-
mestica), 1. 1-2140, b. 1-3500.

Amphibia and Reptiles. Crocodile (Croco-
dilus acutus), 1. 1-1231, b. 1-2286; Frog
(Rana temporaria), 1. 1-1108, b. 1-1821;
Lizard (Lacerta vivipara), 1. 1-1660 ; Siren
lacertina, 1. 1-435, b. 1-800 ; Toad (Bufo
vulgaris), 1. 1-1043, b, 1-2000; Triton (Lis-

BLOOD.

[ 102 ]

BLOOD.

sotritonpunctatus), 1. 1-830; AmphiumaA.
1-340.

Fishes. Carp (Oyprinus carpio),!. 1-2142,
b. 1-3429; Eel (Angwllavulyaris),\. 1-1745,
b. 1-2842; Jack (Esox lucius), 1. 1-2000,
b. 1-3555; Millers Thumb (Cottus gobio),
1. 1-2000, b. 1-2900; Perch (Percajluvia-
tilis), 1. 1-2099, b. 1-2824 ; Tench (Cyprinus
Tinea), 1. 1-2286, b. 1-2722.

The colourless corpuscles do not vary so
much in size in different animals as is the
case with the coloured corpuscles. Those
of the human blood are about 1-2500" in
diameter.

A third corpuscular element of the blood,
related to its formation, is described by
Norris.

The red corpuscles of blood consist che-
mically of Haemoglobine (Haematoglobu-
line) ; and this is composed of a colouring
matter — haematine, and an albuminous sub-
tance — globuline. They are readily altered
in form by most liquids; those of less spe-
cific gravity than the liquor sanguinis dis-
tend them, rendering them larger, paler, and
more transparent, and effacing the lenticu-
lar appearance and the elliptical form when
present. If a small quantity of water be
added, the corpuscles in motion are seen to
be highly elastic, becoming altered in shape
when coming into contact with each other,
but resuming their form when free. If the
liquid be added in large proportion, the en-
velope or cell-membrane becomes extremely
thin and pale, until at last it is no longer
distinguishable ; sometimes it bursts. These
phenomena are the result of endosmosis.
The red corpuscles, however, are not all
equally acted upon : some are much more
affected than others ; some even appear
almost entirely to resist the action of en-
dosmotic agents, and are found but little
altered, even when the blood is mixed with
a large proportion of water. Although
water and other endosmotic agents distend
the coloured corpuscles, and render their
envelopes so extremely transparent that
they can no longer be recognized, yet many
of them may be restored to view by the
addition of reagents which either act exos-
motically, colour them, or render them
opaque — as solution of iodine, of bichloride
of mercury, and various other salts. Dilute
acids act nearly in the same manner as
water, but much more rapidly. Dilute
solutions of alkalies produce the same effect,
but soon dissolve them completely. Solu-
tions of neutral salts act exosmotically,

rendering them smaller, more flattened, and
producing wrinkles, folds, or a granular ap-
pearance in the enveloping membrane. Fre-
quently also they appear covered with little
points, giving them an elegant stellate
aspect ; this stellate or crenate appearance
is not unfrequently seen immediately that
fresh blood is examined under the micro-
scope, especially at the margins of the drop.
Two principal conditions are especially
favourable to its production, viz. a concen-
trated state of the liquid, and an increase
in the proportion of alkaline chlorides ; the
action of alcohol also tends to produce this
condition.

The comparative size of the corpuscles
in the races of man is treated of by Rich-
ardson (M. M. Jn. 1877, xvii. 212).

The corpuscles of the blood of the hepatic
vein are smaller, more spherical, without
the central depression, and resist the action
of water for a longer time than the ordinary
corpuscles ; similar corpuscles are also met
with in the spleen. These are by some
regarded as young newly formed corpuscles ;
while those of the portal vein possess the
ordinary characters.

Matters which coagulate the albuminous
matter of the red corpuscles, such as alcohol,
tannic acid, and creosote, also heat, alter
their form, giving rise to the production
of tail-like processes, with adherent minute
globules, which also cover the surface of
the corpuscles. And by pressure the latter
are broken up into a number of similar
globules.

It is a disputed point whether the red
corpuscles have a cell-wall or not. The
action of osmotic reagents tends to show
that they have ; and " the membrane can
be distinctly seen with 1000 diameters in
the newt's corpuscle after the addition of
magenta and tannic acid " (Rutherford).
Beale shows that they may be crushed into
fragments by pressure on the cover; but
as the haemoglobine surely coagulates, this
is accounted for ; and moreover, the haemo-
globine is readily soluble in water and in
serum ; and it seems difficult to understand
how it resists the solvent action of the serum
unless defended by a cell- wall.

The red corpuscles of the blood contain
or consist of Haemoglobine (Haematoglo-
buline). This may be obtained in a crys-
talline state by adding ether by drops to
defibrinated blood, and shaking until the
bright and opaque colour of the blood is
replaced by that of a syrupy transparence.

BLOOD.

[ 103 ]

BLOOD.

After setting aside for some hours, it sepa-
rates in fine red crystals. Or, on a smaller
scale, place a drop of blood on a slide, and
add twice as much water, mix the two, and
set aside for evaporation. The crystals will
then form, often most distinctly at the
margins.

Under very high powers, a number of very
delicate, colourless, radiating or reticular
filaments may be seen traversing the cor-
puscles, sometimes also the nucleus ; pro-
oably arising from the coagulation of the
contents.

Carbonic acid causes a cloudiness with
enlargement in the red corpuscles, removed
by oxygen or air, which also contracts
them.

Electricity produces smaller or larger
processes, the corpuscles finally becoming
globular and colourless.

The colourless corpuscles are much less
affected by reagents. Water distends them
slightly, rendering their granulations less
distinct. Acetic acid does the same to a
greater extent, bringing to light the nuclei.
Alkalies dissolve them. When blood is
mixed with a large quantity of water, the
mixture shaken and set aside, a pale buff
precipitate subsides ; this consists of some
of the albumen thrown down from the
serum, with shreds and walls of ruptured
coloured corpuscles, a few of the latter un-
altered, and some unaltered or but slightly
changed colourless corpuscles.

Almost immediately after the blood of
the Vertebrata has left the blood-vessels, it
begins to coagulate. Within about three
minutes, the surface of the coagulating blood
becomes gelatinous ; in about ten minutes
it is gelatinous throughout; and after a fur-
ther lapse of time, the coagulation of the
fibrine apparently attains its maximum :
this process, however, is not really com-
pleted until from twelve to thirty-six hours.
We then find a firm red clot immersed in a
yellowish liquid. The fibrine during its
coagulation entangles a large number of
the corpuscles, which impart to it the red
colour ; this is greatest towards the lower
part of the clot. The liquid from which
the clot has separated, the serum, also con-
tains some of the globules in suspension;
most of those not entangled in the clot,
however, subside to the bottom of the ves-
sel. The sp. gr. of the serum is about 1030.
The appearances presented under the micro-
scope by a drop of coagulating blood are
very interesting. If examined immediately

after removal from the body, the cor-
puscles are seen to be diffused irregularly
over the field ; but after the lapse of about
a minute, the red corpuscles unite by their
broad surfaces, gradually arranging them-
selves into rows resembling strings of figs ;
these interlace, forming an irregular red net-
work, within the meshes of which the colour-
less corpuscles are seen (PI. 49. fig. 37).
The latter remain isolated, having no ten-
dency to unite with the former. To observe
these phenomena, the thin glass covering
the drop of blood must not be pressed down ;
otherwise the free motion of the corpuscles
will be impeded. After a time, the fibres
break up, and the corpuscles float separately
in the serum.

The coagulated fibrine is also seen dis-
tributed over the field, partly in a granular
form, but mostly in that of a network of
very delicate fibres. Sometimes the running
together of the red corpuscles begins to take
place immediately the blood has left the
body, and the rows are seen to be formed
very much more rapidly than in the healthy
fluid ; and when this is the case, the upper
surface of the clot will be found to be
free from the red colour, and more or less
cupped or concave : this upper layer is called
the buffy coat, and is in general a sign of
inflammation. Considerable doubt still
exists in regard to the nature of this buffy
coat. It is also met with in blood which has
been covered with a layer of oil before co-
agulation. But in the natural state it arises
from the subsidence of the corpuscles before
the commencement of the solidification of
the fibrine, whereby the particles of the
latter are brought into closer contact, thus
allowing of its greater contraction. Certain
salts prevent the separation of the fibrine in
the form of fibres, and cause it to assume
the form of minute granules or globules.

In addition to the corpuscles above de-
scribed which are constantly found in the
blood, it sometimes contains globules of oil,
and, after meals especially, two distinct
kinds of a white, extremely fine, molecular
substance — one consisting of fat, the mole-
cular base of the chyle, the other a very finely
divided albuminous substance. They render
the blood milky in appearance. The dis-
tinction of the muscular base of the chyle
from the molecular albuminous deposit must
be effected by ether, which dissolves the
latter but not the former ; but great care
is requisite in judging of the action of
ether.

BLOOD.

[ 104 ]

BLOOD.

Some methods have recently been devised
for the enumeration of the blood-corpus-
cles. Malassez uses a glass tube, having a
capillary bore with a dilatation near the
upper end, in which is placed a glass
globule. To this end is attached an india-
rubber tube ; the other end is pointed. The
tube is accurately graduated. An artificial
serum is made of gum acacia and water,
or a saline solution of known strength. The
point of the tube is then inserted in the
blood to be examined, and a certain quan-
tity is sucked up. A measure of the serum
is then drawn in, and the apparatus well
shaken. The corpuscles are thus spread
through the serum so as to be diffused and
readily counted. For this purpose the
mixture is introduced into a capillary tube
fixed to a slide, and the number of corpus-
cles read off by the aid of a micrometer
eye-piece. The proportions of the dilution
must necessarily be carefully taken into ac-
count. The colourless corpuscles can be
enumerated in the same manner. Further
details will be found in Robin, Micr., 477
(figs.) ; or Rutherford, Hist., 62 (figs.).

The colour of the blood of the Vertebrata
varies according to whether it is removed
from the arteries or the veins, in the former
case being of a much lighter and brighter
red than in the latter. It is beyond our
province to enter into the details of the
causes of their difference j suffice it to say,
that it arises principally from an alteration
in the globules, by which they are enabled
to reflect light more copiously.

In the Invertebrata the coagulation of
the blood is imperfect, and the clot much
less firm and copious than in the Verte-
brata.

The uses of the blood scarcely require
mention. It is at the same time the nutri-
trive fluid from which all the tissues of the
body are formed and renovated, and that in
which the components of the secretions are
produced and from which they are separated.
The red particles are subservient to the pur-
poses of respiration ; they are most numerous
in those animals in which the respiratory
function is most active, and which consume
the largest proportion of oxygen, as birds
and mammalia.

Development of the Coloured Corpuscles.
In the Vertebrata, two sets of coloured cc

cor-

puscles are developed. The first, or embry-
onic blood-corpuscles, exist alone, until
lymph and chyle begin to be formed, when
they are gradually superseded by the second.

The first blood-corpuscles are formed from
colourless nucleated cells with granular con-
tents, identical with the formative cells of
the embryo, by their losing the granules
and becoming filled with haematine. These
coloured, nucleated, primary blood-cells,
which are spherical, larger and more deeply
coloured than the coloured blood-corpuscles
of the adult, form, with the colourless for-
mative cells, the only elements of the blood.
Soon, however, many of them begin to in-
crease by division (PI. 49. fig. 36), becoming
elliptical and flattened, and closely resem-
bling the coloured corpuscles of Reptiles,
producingtwo, rarely three or four roundish
nuclei, and then becoming resolved into two,
three, or four new cells by the formation of
one or more annular constrictions. These
corpuscles then gradually lose their nuclei,
become flattened and excavated laterally,
and form perfect coloured corpuscles.

The formation of the second set, or those
produced after birth and in adults, is more
obscure. The most probable view appears
to be that they are produced from the lymph
and chyle-corpuscles, or certain corpuscles
in the spleen and liver, by their losing their
nuclei, becoming flattened, and producing
hsematine. At all events, corpuscles appa-
rently identical with the so-called proper
corpuscles of the chyle, surrounded with a
membrane which is more or less distended
with a red liquid, are met with in the chyle
and lymph, and occasionally, but rarely, in
the blood itself. Physiologists are not
agreed as to the above views ; but the pre-
ponderance of evidence appears decidedly
in their favour. Recklinghausen has di-
rectly observed the conversion of the colour-
less corpuscles of the frog into the coloured
corpuscles.

As unusual constituents of blood, may be
mentioned : —

1. Cells or masses of protoplasm enclo-
sing coloured blood-corpuscles; found in the
blood of the spleen, liver, &c.

2. Granule-cells, either colourless or con-
taining granules of pigment.

3. Peculiar concentric bodies, three or
four times as large as the coloured corpus-
cles of the blood, resembling those found in
the thymus gland.

4. An unusually large number of colour-
less corpuscles in Leucocythaemia.

5. Pus-corpuscles.

6. Caudate cells, sometimes containing
pigment.

7. Crystals of hsematoidine, sometimes

BLOOD.

[ 105 ]

BLOOD.

within the coloured corpuscles, at others
free ; also crystals of hremoglobine (hae-
matoglobuline).

8. The two molecular substances previ-
ously mentioned.

9. Hsematozoa. Filaria hominis', other
species in the deer, dog, rat, &c. ; Bilharzia.

10. Hgematophyta. Bacteria, Bacilli ;
Spirochcete (relapsing fever).

11. Altered colouring matter of the blood,
forming minute rounded or angular black
particles, contained in the colourless cor-
puscles j in splenic disease, and malaria.

It sometimes becomes of importance to
be enabled to determine the presence of
blood in supposed blood-spots, &c., and to
distinguish that of man from that of ani-
mals. As regards the former point, it is a
matter of no great difficulty. When blood
has been dried at ordinary temperatures,
the dried serum and contents of the cor-
puscles redissolve on digestion with cold
water; and this is the condition under
which the blood is generally presented for
examination in such cases. We then have
the fibrine left undissolved, which may be
tested as to its chemical and microscopical
characters (FIBRINE). The liquid is de-
colorized by boiling, and the coagulum as-
sumes a brown colour (!LEMATINE). It
also contains iron, is unaltered in colour by
solution of potash, and contains a proteine
compound. In heating very minute quan-
tities upon a glass slide, the liquid must
always be covered with a slip of thin glass,
to prevent its drying. The mere presence
of blood can thus be chemically determined
without much difficulty ; for these reac-
tions may be observed under the micro-
scope in a very minute quantity ; but the
distinction of small quantities of the blood
of man from that of animals by chemical
means, is impossible. We have therefore
only the morphology of the elements or
the spectral analysis to decide from. The
portions of blood presented for examination
will be almost invariably in a dried state ;
and the red corpuscles, when dried in a very
thin layer, retain so nearly their natural
size and outline, that any kinds of blood
which are distinguishable in the fresh state,
are certainly so when dried; but it will
seldom happen that the blood will be dried
upon a transparent substance, and in thin
layers, permitting of its examination by
transmitted light. It must therefore be
separated from some fabric or structure, and
restored as nearly as possible to its original

appearance. This can be done by digesting
the blood in a solution of bichloride of mer-
cury, Robin's liquid (p. 106), or a f-l-p. c.
salt-solution, and placing it under a bell-
glass for some hours; the red corpuscles may
then be detached with a camel' s-hair pencil,
and examined. Of course, only those cor-
puscles should be measured which evidently
retain their natural form. The red corpuscles
of the mammalia are readily distinguishable
from those of the lower classes in the animal
kingdom by their circular discoidal form and
the absence of a nucleus ; but those of indi-
vidual groups can only be recognized by a
difference in size. And great difference of
opinion exists as to whether the blood-cor-
puscles of man can be distinguished from
those of other animals. This point has been
particularly discussed by Richardson, Am.
Jn. Med. Sc. 1874, 102 (M. M. Jn. 1874,
xii. 130) ; and Woodward, M. M. Jn. 1875.
xiii. 65.

Virchow recommends that the blood-spots
be mixed with dried and powdered chloride
of sodium ; next, that glacial acetic acid be
added, and the mixture evaporated at 212°,
when the blood-crystals (chloride of hsema-
tine) are abundantly deposited.

We should recommend those who are
likely to undertake such investigations to
make their own table of sizes ; for it curi-
ously happens that in general the size of
the same objects given by different observers
varies considerably. This arises probably
from using too low a power, want of practice,
and the use of a false standard. And we
should not advise any one to attempt to form
a judgment in a judicial question of this
kind except he be thoroughly acquainted
with the use of the microscope and micro-
metric investigations and the most difficult
spectroscope, and has made numerous ex-
periments upon this special point.

The corpuscles of the blood are best stu-
died while existing in the serum of that
liquid; but the white of egg neutralized with
acetic acid exerts but little action upon them,
as is also the case with a solution of bichlo-
ride of mercury. The colourless corpuscles
are most easily recognized when the blood
has been mixed with water.

They are best preserved when dried in a
very thin layer upon a slide — a drop of blood
being placed upon the slide, and the latter
placed in a perpendicular position, so that a
very thin layer will remain ; in the liquid
state, a solution of 1 part of bichloride ol
mercury, and 2 of chloride of sodium, in

BLOOD ON BREAD.

C 106 ]

BODO.

200 parts of water, will preserve them well
(Robin).

BIBL. Kolliker, Hand. d. GewebeL ; the
Manuals on Physiology, by Miiller, Valen-
tine, Wagner, Carpenter, Forster, and
Kirkes ; the Dictionaries of Todd and Bow-
man, and Wagner; Hassall, Micr. An. ;
Gulliver, Gerber'sAnat. ; Ann.N. H. xvii. ;
Pr. Zool. Soc. 1862, p. 91 ; Schmidt, Dia-
gnostik verddchtiger Flecke, &c. 1848 ; Frey,
Histologie, and the copious BIBL. therein ;
Browning (Spectroscope), Mn. Mic. Jn. ii.
p. 116 ; Rollett, Strieker's Handb. i. p. 574 ;
Cornil and Ranvier, Hist. path. ; Ruther-
ford, Hist. ; Beale, How fyc. ; Ralfs, Action
of Chloral hydrate, Chloroform, and Prussic
acid on (M. M. Jn., 3871, vi. 75) ; Sorby,
M. M. Jn. 1871, vi. 9 (Spectroscope) ; Rich-
ardson, ibid. 1876, xv. 30 (Sp.) ; Carpenter,
Micr. 107; Beale, How Sfc. 273; Osier,
M. M. Jn. 1874, xii. 141; E. Hart, Qu.
Mic. Jn. 1881, xxi. 132 (mum.} ; Klein,
Hist. ; Lewis, Qu. Mic. Jn. xix. 245 (Hce-
matozod) ; ibid. 1879, 109 (Rats) ; ibid.
xix. 356 (Microphytes) ; Norris, Jn. Mic.
Soc. 1880, iii. 229 ; Dowdeswell, Qu. Mic.
Jn. 1881, xxi. 154.

BLOOD ON BREAD.— Bread, flour,
paste, and similar substances are sometimes
attacked by a fermentation-fungus, which
produces patches of a blood-red (or some-
times of an amber) colour. Most authors
attribute the plants to Oidium, or to forms
of Penicillium. Ehrenberg observed only
minute corpuscles, which he called Monas
prodigiosa. We have found these patches
on sour paste, of red and yellow colour,
consisting of isolated oval cells not more
than 1-3000" in diameter ; and they were
associated with Penicillium glaucum, of
which they are probably a conidial form.
This form is called Cryptococcus glutinis by
Fresenius, who thinks it distinct from the
so-called Monas prodigiosa of Ehrenberg,
which he found in the form of corpuscles
about 1-24000 to 1-48000" in diameter.
Montagne regards the plant as a PalmeUa
(prodigiosa) ; and H. O. Stephens is of the
same opinion. Cohn rightly refers this or-
ganism to Micrococcus.

This substance sometimes occurs on de-
caying Fungi. The blood-rain on damp
wall-paper, calico, and old gourds and
melons, is the mycelium of a species of
Epicoccum.

BIBL. Ehrenb., Fresenius, Mycologie,
Heft ii. p. 78 ; Desnon, Mem. Soc. d. Sc.
Nat. de Cherbourg, iv. p. 19 ; Montagne,

Compt. Rend. 1852 ; Ann. N. H. 2 ser. x.
p. 309 ; Berkeley, Crypt. Bot. p. 264 ; Ste-
phens, Ann. N. H. 1853, xii. p. 409, pi. 17.

BLOOD-VESSELS. See VESSELS.

BLOOD- WORM .—The larva of Chiro-
nomus plumosus.

BLOXAMIA, Berk, and Br.— A genus of
Spheeronemei (?) (Stylosporous Fungi), con-
sisting of minute punctiform sacs, soon
bursting above, containing closely packed
tubes producing each a row of squarish
spores. An anomalous genus, allied to
Cystotrichia and Myxormia. B. truncata
has been found on dead Wych elms.

BIBL. Berk. & Broome, Ann. N. H. 2 ser.
xiii.468, pi. 16. %. 17; Berk. Crypt. Bot. 329.

BL YT'TIA, Endlich.— A genus of Pelliere
(Hepaticae) founded on the Jungermannia
Lyellii of Hooker, remarkable for the double
envelope of the fruit, the outer being
very short, dentate and laciniated, while
the inner forms a largish, somewhat plaited
cylinder. The antheridia arising from the
rib are covered
by incumbent
scales, which
are sometimes
much laciniated
and crowded
together, some-
times (J. hi-
bernica, Hook.
Brit. Jungerm.}
scarcely tooth-
ed, lax and lar-
ger.

BIBL. Hook-
er, Br. Jung.

Nees, & tLeier- Blyttia Lyemi' ma^' 2 diam-
moose, iii. 313 ; Flora Danica, t. 2004.

BO'DO, Ehr.— A genus of Infusoria, be-
longing to the family Monadina. (Monads
with a tail.)

Char. A tail; no eye-spot present; mouth
terminal ; animals sometimes united in the
form of a mulberry or a bunch of grapes.

Ehrenberg describes eight species.

Some of them inhabit the intestinal canal
of frogs, insects, &c. One is green, the rest
are colourless.

Dujardin regards one species (Bodo gran-
dis) as comprising both his Heteromita
ovata and a species of Anisonema ; the
others he considers imperfectly examined
species belonging to his genera Cercomonas
and Amphimonas.

Bodo grandis, E. (Heteromita ovata, D.).

BCEHMERIA.

[ 107 ]

BONE.

Fr. wat. ; length 1-940 to 1-720" (PL 30.
fig. 18 a).

Bodo socialis, E. (PI. 30. fig. 18, b, c).
Fr. wat. ; length 1-3000".

BIBL. Ehrenberg, Inf. j Dujardin, Inf. j
Pritchard, Inf. ; Kent, Inf. 254.

B(EHME'KIA. Jacq.— A genus of Urti-
caceous plants closely allied to our common
Stinging Nettle, and characterized, like that
and other species of Urtica, by containing
tenacious liber-fibres. Two species are em-
ployed in the East Indies on this account.
B. nivea, Gaudichaud, yielding the fibre from
which Chinese grass-cloth (PL 28. fig. 25) is
manufactured, is a native of China, where it
is largely cultivated, also in Sumatra, where
it is called Caboose, and at Pulo Penang,
where it is called Kami. JB. Puya, Wallich,
yields the Pooah or Puya fibre of Nepaul
and Sikkim (PI. 28. fig. 26), which has long
been extensively used in India, and is said to
equal the best European flax when properly
dressed j being ordinarily roughly prepared,
it is dirty and bad-coloured, but makes ex-
cellent sail-cloth and cordage.

BIBL. Hooker, Jn. of Bot. i. & iii.

BOLACOT'RICHA, Berk.&Broome.— A
genus of Mucedines (Hyphomycetous Fun-
gi), containing one species, B. grisea, found
growing upon dead cabbage-stalks, old mats
made of Typha, &c., in tufts forming large,
effused, grey patches. Messrs. Berkeley and
Broome express themselves doubtfully as to
its real affinities. In habit it approaches
Myxotrichum, but differs in its simple threads
and large spores, while the spores are not in
chains as in Sporodum, or minute and linear
as in Tricholechonium. The threads are pale
purple under the microscope, strongly curved
at the tips like tendrils.

BIBL. Berkeley and Broome, Ann. Nat.
Hist. ser. 2. vii. p. 97, pi. 5. fig. 4.

BOLE'TUS, Bill.— A genus of Polyporei
(Hymenomycetous Fungi), consisting of pi-
leate Fungi,or 'toad-stools,' often of large size,
growing in woods. See BASIDIOSPOBES.

BOLIVI'NA, D'Orb.— A subdivision of
the Bulimine Foraminifera, in which the
peculiar infolded notch-like aperture is re-
tained ; but the chambers grow bilaterally
alternate (Enallostegian), instead of triserial
and obliquely spiral (Helicostegian), as in
Bulimina proper. The shell is delicate and
porous. B.punctata and B. costata are the two
leading forms. Varieties are common in all
seas, and date from the Cretaceous period.

BIBL. D'Orbigny, For. Foss. Vien. 239 ;
Carpenter, Introd. For. 196.

BOMBA'CEJS.— A subdivision of the fa-

mily of Dicotyledonous plants called Stercu-
liaceae, some genera of which are called Silk-
cotton trees, from the long hairs which enve-
lope their seeds, as in the true cotton plants.
These hairs (from Chorisiaspeciosa, Bombax,
sp. var., JSriodendron, sp. var.) cannot be
spun, but are used for stuffing cushions, &c.
The Adansmia, or Baobab-tree, produces a
pulpy fruit, which contains a considerable
proportion of starch. The wood of some
kinds, as of Bombax pentandra and Pachyra
( Carolinea) minor, is remarkable for its light-
ness and almost corky texture, resulting from
being composed almost exclusively of paren-
chymatous cellular tissue, with scattered po-
rous ducts and true wood-cells. See WOOD.
BONE. — It need scarcely be stated that

Fig. 63.

Magnified 90 diameters.

Segment of the transverse section of a human meta-
carpal bone, a, outer surface of the bone, Avith the
outer laminae ; b, inner surface next the medullary ca-
nal, with the inner laminae; c, orifices of the divided
Haversian canals, with their laminae; d, interstitial
laminae ; e, lacunae, with their canaliculi.

BONE.

[ 108 ]

BONE.

bone is the hard substance serving to give
firmness to the bodies of the Vertebrata, to
protect their delicate organs, and to form
points of attachment for muscles.

To the naked eye, bone appears to consist

Fig. 64.

Magnified 60 diameters.

Haversian canals from the superficial layers of a
human femur, at eighteen years of age, treated with
muriatic acid, a, Haverdian canals; 6, osseous sub-
stance with lacunae.

Fig. 65.

**'

d'

c

Magnified 25 diameters.

Segment of a transverse section of the shaft of the human femur, at eigh-
teen years of age. a, Haversian canals; 6, their internal orifices; c, the
external orifices ; d, osseous substance, with lacunae. There are no trans-
verse sections of the Haversian canals, nor concentric laminae.

of an apparently homogeneous basis, sur-
rounding certain cavities, areolae or can<rUi •
these are most numerous and larger towards
the centre, where, in the Mammalia and Birds,
they form a larger cavity called the medullary
canal. This contains the marrow in the
former class, but air in the latter. Hence
we'recognize in bone an outer compact and
an inner spongy portion.

On examining a thin transverse section of
bone under the microscope by transmitted
light and with a low power, it is found to
exhibit a number of round or oval apertures;
these are the orifices of the divided vascular
or Haversian canals (fig. 63 c). These canals
contain blood-vessels in the natural state.
They are cylindrical, sometimes flattened,
communicate freely with each other and the
medullary canal, and also open upon the
outer surface of the bone. They mostly run
parallel with the axis in the long bones ;
whilst in the flat bones they are parallel to
the surfaces, frequently following a radiating
course. The branches by which they com-
municate with each other
are either transverse or ob-
lique, and pursue a radiating
or tangential course.

Hence in a longitudinal
or superficial section of bone,
the canals are seen running
longitudinally, here and
there connected by anasto-
mosing branches, and form-
ing elongated somewhat
rectangular meshes (fig. 64).
In transverse sections of
foetal and incompletely de-
veloped bones, scarcely any
of the apertures aremet'with,
but the canals are seen pur-
suing a tangential or radial
course (tig. 65 a) ; so that
the bones appear to consist
of short thick layers, each of
which belongs to two canals,
which separation is also in-
dicated by a faint median
line in each layer.

The Haversian canals vary
considerably in size, from
about 1-1000 to 1-200".

The osseous substance or
basis of bone possesses a la-
minated structure. The
laminae are visible in sec-
tions of dried bone (fig. 63
«, 6), but much more

[ 109 ]

Magnified 250 diameters.

Portion of a transverse section of the shaft of the hu-
merus, treated with oil of turpentine, a, Haversian
canals ; 6, their laminae, each lamina with a lighter and
a darker portion, and radiating striae in the latter ; c,
darker lines, probably indicating greater interruptions
in the deposition of the osseous substance ; d, lacunae
without evident canaliculi.

distinctly in bone from which the inorganic
matter has been removed by digestion in
dilute muriatic acid. In this the laminae
are easily separable. They frequently ex-
hibit a fibrous appearance ; and near the
surfaces of the bones they run parallel with
these surfaces (fig. 63 «, 6) ; but in the other
portions they mostly surround the Haver-
sian canals concentrically (fig. 63 d}.

When a section of bone is examined with
a somewhat high j>ower, it exhibits nume-
rous dark spots, with fine lines branching
from them on all sides ; the former are the
lacuna, bone-corpuscles, or bone-cells (fig.
67 c, 6) ; and the latter are the canaliciili or
calcigerous canals (fig. 68 6, c, cT). They
derive their dark appearance in dried bone
from containing air : if this be displaced by
immersion in oil of turpentine, they become
so transparent as to be scarcely distinguish-
able (fig. 66) ; and when examined by re-

BONE.

Fig. 67.

w

Magnified 100 diameters.

Section of the surface of the shaft of the femur, a,
Haversian canals ; 6, side view of the lacunas in the
Haversian laminae ; c, surface view of lacunae.

fleeted light, they appear white. The la-
cunae are generally longer than broad, and
flattened. They are about 1-1100" in
length, 1-2000 to 1-2800" in width, and
1-3800 to 1-6000" in thickness; but their
dimensions are subject to great variety.
The canaliculi vary in breadth from
1-20,000 to 1-60,000" j and at their narrow-
est part, which is furthest from the lacunae,
they anastomose with those of the adjacent
lacunae.

The walls of the lacunae and canaliculi
consist of a homogeneous calcified mem-
brane.

In a transverse section of bone, the lacunae
of the laminae surrounding the Haversian
canals are seen to be placed tangentially to
the orifices of these canals, as in figs. 66
and 68 ; whilst those of the laminae near
the surfaces are parallel with these surfaces
(fig. 63).

In a longitudinal section made through
the Haversian canals, they appear arranged

Magnified 300 diameters.

Part of a transverse section of the shaft of the humerus.
a, Haversian canals ; b, c, d, lacunae with their canaliculi.

Fig. 71.

Magnified 350 diameters.

Portion of the outer surface of the tibia of a calf.
The dots represent the orifices of the canaliculi,
the larger dark indistinct spots are their lacunas
seen through the osseous substance.

Fig. 70.

Magnified 350 diameters.

Cartilage of bone, after boiling in water, a, la-
cunar corpuscles ; 6, nuclei.

Magnified 450 diameters.

Lacunae (surface view) with the canaliculi, from the parietal bone. The dots seen
upon or between the lacunas represent divided canaliculi, or their orifices opening
into the lacunae; a, a, a, groups of transversely divided canaliculi.

BONE.

BONE.

in numerous longitudinal rows running par-
allel with the Haversian canals (fig. 67).
The general arrangement is, that the long
axis of the lacunae is parallel with the la-
minae in which they are contained, or be-
tween which they are situated.

When the section coincides with the sur-
faces of a set of the lacunae, they present a
very elegant round or oval form (fig. 71),
irregularly surrounded by a perfect tuft of
canaliculi, which, being turned directly to-
wards the observer, appear more or less
shortened, and a small number of others,
which are diffused through the surface of
the lamellae. Here and there, in the thinnest
portion of the section, a group of trans-
versely divided canaliculi is seen (fig. 71
a, a), without the lacunae to which they
belong, giving the substance a sieve-like
appearance. At the outer and inner surfaces
of the bones, the canaliculi terminate by
open mouths (fig. 69) ; and those nearest
the Haversian canals open into them.

Sharpey's perforating fibres are calcified
pointed fibres, running from the periosteum
towards the Haversian canals ; they are ir-
regular and variable, and are best seen in
the bones of amphibia and fishes.

If the cartilage of bone be boiled for two
or three minutes in water or a solution of
caustic soda, the bone-cells or protoplasts
and their nuclei are often rendered very dis-
tinct (fig. 70). After macerating bone in
dilute muriatic acid also, the lacunar
corpuscles, with longer or shorter processes,
become isolated, and appear as independent
formations.

In regard to the minute structure of bone,
independently of the lacunae and their cana-
liculi, a dry polished section exhibits a very
delicate dotted appearance, which makes the
bone appear granular, as if composed of
closely aggregated pale granules, about
1-50,000 to 1-60,000" in size. This is best
seen in a transverse section.

When bone is calcined and the residue is
rubbed between two pieces of glass, or when
bone is digested in a Papin's digester, minute
inorganic granules are left ; these are oval
or oblong, frequently angular, and are about
1-10,000 to 1-20,000" in diameter.

Hence bone probably consists of an inti-
mate mixture of organic and inorganic
matter, in the form of minute, firmly united
granules.

The above remarks apply to human bones ;
and those of the other Mammalia
essentially in structure with the former.

In Birds, the Haversian canals are more
numerous and smaller than in the Mam-
malia, and frequently run in a direction at
right angles to the shaft ; the lacunae are
also more numerous and smaller, and the
canaliculi very tortuous.

In Reptiles and Amphibia they are few
and very large, larger than in either of the
other classes ; the lacunae and the canaliculi
are also very large, and the latter very
numerous.

In Fishes, the structure is more irregular :
there are no concentric laminse ; the Haver-
sian canals are sometimes absent, at others
very large and numerous; frequently the
lacunae are absent, whilst the canaliculi are
unusually long and elegantly wavy and
branched.

The structures representing the bones in
the Invertebrata are noticed under the re-
spective classes.

The marrow or medullary tissue of bones,
consists of ordinary fatty tissue, free fatty
matter, a particular liquid, and cells, with
vessels and nerves, surrounded and traversed
by a small quantity of areolar tissue.

In the foetal or red marrow, numerous
marrow-cells resembling the colourless cor-
puscles of the blood are met with; also
some comparatively very large or giant cells,
containing numerous nuclei (fig. 72) : K61-
liker's osteoclasts.

Fig. 72.

Magnified 350 times.

Giant cells, or Myeloplaxes, containing numerous
nuclei, from the very young marrow of the flat bones
of the human skull.

When animals, especially young ones, are
fed with madder, the bones speedily acquire
a beautiful red colour, principally around
the Haversian canals, because it is here that

BONE.

the process of formation of new bone
is most active ; and the earthy mat-
ter precipitated from the blood car-
ries down with it the colouring
matter of the madder.

The blood-vessels of bone which
are distributed to the marrow (the
nutrient vessels), enter particular ca-
nals on the external surface ; whilst
those connected with the Haversian
canals are derived from the perios-
teum and from those of the marrow.
The two sets anastomose freely.

Chemically, bone consists of gela-
tine (not chondrine, as in cartilage),
with phosphate of lime, small quan-
tities of carbonate of lime, carbonate
of magnesia, fluoride of calcium, and
sometimes a little oxide of iron and
magnesia.

By digesting bone with dilute
muriatic, chromic, or picric acid, the
inorganic matter is removed, and
by treatment with solutions of alka-
lies or incineration, the inorganic
substance or so-called cartilage may
be separated.

Fig. 73.

«r.«:.

Magnified 20 diameters.

Perpendicular section of the margin of the shaft of
the femur of a child, two weeks old, showing the calci-
fication of cartilage, a, cartilage and its cells ; 6, mar-
gin of calcification ; the dark stripes represent the cal-
cification of the intercellular substance, which precedes
that of the cartilage-cells, indicated by the lighter por-
tions; c, compact calcified layer near the calcifying
margin ; e, cancelli formed by the absorption of the
calcified substance.

Magnified 300 diameters.

Section of the margin of calcification of the condyle of the femur
of a child two years old, affected with rickets, a, cartilage-cells,
single and multiplying, in rows; 6, c, more or less striated inter-
cellular substance ; d. cartilage-cells at the very commencement
of secondary deposition ; e, the same in a more advanced state,
with greatly thickened walls, indications of the canaliculi, and
commencing deposition of calcareous salts in the walls, hence
their darker colour, the nuclei still distinct ; f, still more deve-
loped and calcified cells imbedded in the intercellular substance
g, which is also becoming calcified.

In the development of bone, first the cells
of the (primary) cartilage multiply by en-
dogenous cell-growth, forming longitudinal
rows or irregular heaps. . These fuse and
liquefy, so as to produce canals and cancelli,
in which blood-vessels and medulla are
formed. Earthy matter is then deposited
in the cartilage, in a finely granulated form
(fig. 73) ; thus we have calcified cartilage
— but not bone.

Absorption of the calcified cartilage next

1 1 1 1*11 11 • i

takes place, by which larger cancelli and
canals are formed. Lastly deposition on the

BONE.

[ 113 ]

BORACIC ACID.

walls of the cancelli and canals, of genera-
tions of stellate connective tissue corpus-
cles (osteoblasts), forming a pseudo-carti-
lage, occurs, which becomes calcined to form
the true bone; the absorption of the calci-
fied cartilage, and the deposition in its place
of the new tissue, continuing until the
structure of the bone is perfected.

But in certain bones, as the flat skull-
bones, the jaw-bones &c., the bone is formed
without the aid of cartilage. Here the in-
ner surfaces of the periosteum produce the
osteoblasts, which ultimately become the
bone-corpuscles.

In certain morbid conditions, as in rickets,
the development of the bone is arrested at
the state of ossified cartilage ; secondary
deposit occurring in the cells of the primary
cartilage as in the case of vegetable cells
(tig. 74), the spaces left having great
resemblance to the lacunae and canaliculi of
bone.

Adventitious bone agrees in general struc-
ture with the normal ; and is met with in
all stages of development.

To examine the structure of bone, thin
sections are requisite. The method of ma-
king these is described under PREPARATION.
By macerating bone in muriatic acid dilu-
ted with from 10 to 20 parts of water, or
nitro -chromic acid, the inorganic matter is
removed, the cartilage being left. Thin
sections of this can theii be readily made,
and stained with picro-carrniue or purpu-
rine.

The canaliculi are not easily seen when
sections of bone are immersed in liquids ;
for these fill them up. But it is a difficult
matter to measure the lacunae, unless the
section be moistened with turpentine or
other liquid.

Very thin sections may be preserved in
the dry state ; those which are thick may
be mounted in inspissated Canada balsam,
which does not easily enter the canaliculi,
yet greatly increases the general trans-
parency of the section.

BIBL. Kolliker, Mikr. Anat. ii. ; Tomes,
Todd's Cyd. Anat and Phys., art. Osseous
Tissue; Quekett, Tr. Mic. Soc. 1846;
Quain and Sharpey, Anat. ; H. Miiller,
Sieb. # Kott. Zeitschr. ix. 147; Rutherford,
Hist. 82 ; Schoney, Sch. Arch. xii. devel.
(M. M. Jn. xvi. 1876, 67, figs.); Frey,
Histoloqie, and the full BIBL. therein.

BONNEMAISO'NIA, Ag.— A genus of
Laurenciaceae (Florideous Algae), bearing
pear-shaped spores in stalked ceramidia.

B. asparagoides (PI. 4. fig. 15) has a frond
4 to 12 inches long, growing near low-water
mark or deeper, of delicate feathery character
and deep crimson colour.

BIBL. Harvey, Phyc. Brit. pi. 61; Br.
Mar. Algce, p. 97, pi. 12 D ; Greville, Alyce
Br. p. 106, pi. 13.

BORACIC ACID is the acid of the
well-known salt, borax, in which it exists
combined with soda, in the proportion of two
atoms of the acid to one of the base. Boracic
acid is prepared by mixing three parts of
borax dissolved in twelve parts of boiling
water with one part of sulphuric acid or
common oil of vitriol. As the mixture cools,
the boracic acid separates in the crystalline
form. It may be purified by re-solution in
hot water, and subsequent cooling ; finally,
the crystals are pressed between blotting-
paper, and dried. Boracic acid belongs to
the doubly oblique prismatic system ; and
the crystals possess two optic axes. Those
deposited from the hot aqueous solution are
mostly six-sided plates ; they exhibit the
phenomena of analytic crystals, but at their
lateral surfaces or edges only ; and when
their entire surface appears dark or co-
loured with the polarizer alone, the crystals
are found to be laminated. But when an
alcoholic solution of boracic acid is evapo-
rated on a slide, or, still better, when some
phosphoric acid is added to a solution of
borax, and the mixture evaporated, minute
disks or spherules of the acid are formed ;
these when carefully examined, are seen
to be composed of minute needles radiating
from a centre, exactly as in the oxalurate
of ammonia. In some of them the needles
are so closely in contact that they are un-
distinguishable and the circumference of
the disk appears entire ; in others, the free
extremities of the needles are seen projecting
beyond the circumference. They are per-
fectly colourless, and almost transparent
when viewed by ordinary light, immersed in
balsam. But when examined with polarized
light, each disk exhibits the most beautiful
cross and coloured rings, just as in the case
of the oxalurate of ammonia, in which we
have described the phenomenon more fully.

In some of the specimens of boracic a.cid
the crystals form elegant arborizations,
which also possess considerable analytic
power.

The proportions of phosphoric acid and
borax requisite to produce the disks cannot
be laid down : they can only be prepared by
accident in a number of trials. Even the same

BORRERA.

BOTRYDINA.

solution will sometimes yield them, at others
not. Drops of the solution should be placed
upon a number of slides, and these laid
upon a warm iron plate. The disks are much
more beautiful than those of oxalurate of
ammonia, appearing more transparent and
the colours more brilliant, probably from
their being more highly refractive. They
are difficult also to preserve. Even when
mounted in Canada balsam, they deliquesce
after a time, and large crystals take their
place.

BIBL. Fox Talbot, Phil. Tr. 1837;
Brewster, Optics, 1853.

BORRE'RA, Ach.,=PHY8CiA.

BOS'MINA, Baird.— A genus of Ento-
mostraca, of the order Cladocera, and family
Daphniadse.

Char. Head terminated in front by a
sharp beak directed forwards, and from the
end of which project the long, many-jointed,
curved and cylindrical superior antennae ;
inferior antennae two-branched, one branch
with three, the other with four joints ; five
pairs of legs.

B. longirostris (PL 20. fig. 2). Superior
antennae with twenty joints. Fr. water.

BIBL. Baird, Brit. Entom. p. 105 ; Ley>
dig, Daphnid. p. 244 ; Norman and Brady,
Br. Entom. (North, and Durham Trans.

l' *BOSTRYCH'IA, Fries. See CYTISPORA.

BOSTRYCH'IA, Montagne.— A genus
of Rhodomelaceae (Florideous Algae).

B. scorpioides. Frond purple, slender,
branches involute at the end. Marine.

BIBL. Harvey, Mar. Alga, 79.

BO'TACHUS, Brady.— A genus of Cope-
podous Entomostraca.

B. cylindratus.

BIBL. Brady, Copepoda, i. 140.

BOTHREN'CHYMA.— Pitted tissue of
Plants. See TISSUE, Vegetable, and refer-
ences under that head.

BOTHRIOCEPH'ALUS, Rudolphi.— A
genus of Entozoa, of the order Sterelmintha,
and family Cestoidea.

Char. Body long, flat, soft and jointed,
joints short; head slightly tumid, oval or
somewhat quadrangular, with two opposite
depressions, or with four ear-like appen-
dages, or with four depressions furnished
with hooks ; genital pores mesial.

The species are common in fish and
birds, more rare in mammalia, and very
rare in reptiles. They usually inhabit the
alimentary canal, sometimes the abdominal
cavity.

Thirty-four species are enumerated by
Rudolphi, ten of which are doubtful. Du-
jardin enumerates twenty-three species.

Bothriocephalus lotus (Tcenia lata, the
broad tape -worm) is met with in the human
intestines. The head is somewhat ovoid,
with two elongated opposite depressions,
but no hooks ; the neck generally not dis-
tinct. The joints of the body are very
broad in proportion to their length. The
orifices leading to the ovaries are situated
in the centre of the flat surface of each
joint; and around them the oviducts are
seen, having a radiated or stellate appear-
ance. Sometimes a minute body can be
seen projecting from the genital pore — the
male organ. It exclusively inhabits the
small intestines. It is rare in England.
It is 20 feet or more in length. Ova
1-350" long. Embryos ciliated, with six
hooks.

B. cordatus, with the head cordate, is
found in dogs, and rarely in man (Leuckart,
i. p. 438, fig.).

B. cristatus. With two prominences
forming a papillate rostrum. Human ;
•rare..
.-. -See T^NIA and ENTOZOA.

- : EUfiL. Rudolphi, JEntoz. Si/nops. ',,
Wiirmer, &c. ; ihijardin, Helminth. ; Esch-
richt, Die Bothr. ; Blanch ard, Ann. d. Sc.
Nat. 3 se"r. xi.; Davaine, Traite #<?.;
Leuckart, Parasit. i. p. 416 ; Cobbold. Pa-
rasites, p. 106.

BOTRYCH'IUM, Swartz.— A genus of
Ophioglossaceous Ferns. Moon-wort (Bo-
trychium Lunaria] is an indigenous repre-
sentative.

BIBL. Hooker, Syn. Fil., p. 447.

BOTRYDl'NA, Brfb.— A genus of Pal-
melleae (Confervoid Algae). B. vulyaris,
the only species (PL 7. fig. 9), forms a
somewhat gelatinous, blackish-green stra-
tum on the ground, on trees, or on mosses,
in damp places.

The spores, about 1-10,000" in diameter,
increase by cell-division till they form sphe-
rical bodies composed of many cells, the pe-
ripheral layer of which is diaphanous, the
internal green from granular contents ; the
internal vesicles multiply, with constant in-
crease of size of the whole, until the little
fronds acquire the dimensions of a pin's
head (1-36", Kiitzing) ; the whole cellular
structure is firmly coherent.

BIBL. Bre"bisson, Now). Genr. cTAlg.
(1839), p. 3, fig. 3 ; Meneghini, Monoy. Nos-
foc/*..p..98, pi. 13. fig. 2; Hassall, Freshic.

BOTRYDIUM.

BOTRYLLOIDES.

Fig. 75.

Alga, 320, pi. 81. fig. 2 ; Kiitzing, Tab. Phyc.
pi. 10 ; Rabenhorst, Fl. Alg. ii. p. 37.

BOTRYDTUM, Wallr. (Hydrogastrum,
Desv.). — A genus of Siphonese (Confervoid
Algas), of which one species is found in
this country, growing upon damp, clayey
ground, the dried-up bottoms of ponds, &c.
A single plant, as developed from a spore or
gonidium, exhibits a remarkable character,
having a lower branched filamentous por-
tion, growing in the ground, and an erect
spherical or obovate portion, or head, about
the size of a mustard-seed, of a bright green
colour, the whole structure consisting
merely of a single cell, with one continuous
cavity running through the entire plant.
The figure (fig. 75) represents such a spe-
cimen, with a second
budding from it by ve-
getative increase ; and
in this way the plants
come to form tufts or
groups, like little bun-
ches of grapes ; hence
the name. The cell-
membrane acquires
considerable thickness ;
and at the period when
it is softening, and
about to dissolve to
allow of the escape of
the gonidia, it is seen
clearly to be composed
of numerous lamelte,
like that oi Hydrodic-
tyon. The globular head is lined, in the
full-grown specimens, with a layer of pro-
toplasm (primordial utricle), containing
abundance of chlorophyll-globules ; and at
a certain period breaks up into numerous
free globular asexual gonidia.

When the air is dry, the protoplasm de-
scends into the branches, in little masses,
each forming a subterranean sporange, pro-
ducing zoospores; which are also some-
times formed in a vesicle springing above
ground, and capable of resisting desicca-
tion.

Under the direct rays of the sun, the
head-protoplasm breaks up into cells, at
first green, then red. These, when free,
produce biciliated zoospores, which copu-
late.

BIBL. Greville, Alffee Br. 196, pi. 19;
Hassall, Fr. Alga, 305, pi. 77. fig. 5 ; Kiit-
zing, Nova Acta, xix. pt, 2, pi. 69. figs. 1-10 ;
Braun, Verj. (Ray Soc. 1853) ; Itzigsohn,
Sot. Zeit. xiii. p. 257; Sachs, Bot. 275;

Eostafinski & Woronin, Bot. Zeit. 1877
(Qu. Mic. Jn. 1878, xviii. 446).

BOTRYL'LnLE.— A family of Tunicate
Mollusca. Distinguished by the individual
bodies being united into a common mass,
which is attached ; and by the mantle being
united to the test at the orifices only.

These animals form translucent gelatinous
or cartilaginous masses, of various hues of
orange, purple, yellow, blue, grey, and green ;
and are found under stones, or rocks, or in-
crusting sea- weeds, near low-water mark.
The bodies are often arranged in elegant
star-like clusters or systems ; the anal ori-
fices usually terminating in a common cen-
tral cavity or vent. Genera :

Aptidium. Form variable; systems nu-
merous ; central cavity none ; bodies with
thorax, fore and hind abdomen ; branchial
orifice six-rayed; anal simple and indis-
tinct,

Sidymim. Incrusting; systems conical,
truncate and starred at the summit, centre
depressed ; thorax and abdomen present ;
branchial orifice eight-rayed.

Polyclinum. Form variable ; systems nu-
merous, convex and radiating, with cen-
tral cavity; bodies with thorax, fore ab-
domen, and long-stalked hind abdomen;
branchial orifice six- rayed; anal projecting
horizontally.

Amaroucium. Lobed or incrusting, ses-
sile or stalked ; systems numerous, with a
central cavity ; bodies as in Aplidium.

Leptoclinum. Thin, incrusting ; systems
numerous; bodies with thorax and ab-
domen; branchial orifice six-rayed; anal
opening into a common vent, more or less
branched.

Distoma. Sessile; cartilaginous; form va-
riable ; systems numerous, circular ; bodies
in one or two rows at unequal distances
from a common centre, with thorax and
stalked abdomen; branchial and anal ori-
fices six-rayed.

BotryUus. Incrusting, gelatinous; sys-
tems numerous ; bodies horizontal, in stars
round a common vent ; bodies undivided ;
branchial orifice simple, remote from the
vent.

Botrylloides. As the last, but stars ir-
regular and ramifying; bodies vertical;
orifices approximated.

Syntethys. Mass sessile, gelatinous, form-
ing a single system; bodies sessile; ori-
fices simple, without rays.
BIBL. See the Genera.
BOTRYLLOI'DES, M.-Edw.— A genus
i2

BOTRYLLUS.

BOTRYTIS.

of Tunicate Mollusca, of the family Bo-
try 11 i dae.

Char. See BOTRYLLIDJE.

Four species : B. Leachii, hyaline, pur-
plish, stars mottled white and yellow ; B.
albicans, transparent, stars white ; B. roti-
fera, yellowish, systems speckled with red ;
B. rubrum, intense orpiment-red.

BIBL. Gosse, Mar. Zool. ii. 34 ; Forbes
and Hanley, Brit. Moll. i. 23.

BOTRYL'LUS, Gaertn. — A genus of
Tunicate Mollusca, of the family Botryl-
lidae.

Char. See BOTRYLLIDJE.

Six species : B. Schlosseri (PI. 18. fig. 20),
stars numerous, individuals ten to twenty
or more, yellowish and reddish, common ;
B. poly cy dm, stars numerous, individuals
eight to twenty or more, bluish, general;
B. violaceus, B. smaragdus, B. bivittatus,
and B. gemmeus.

BIBL. Gosse, Mar. Zool. ii. 34; Forbes
and Hanley, Brit. Mollusc, i. 19.

BOTRYOCOC'CUS, Kiitzing.— A genus
of floating Palmellese (Confervoid Algae),
forming lobed and irregular bodies enclosed
in a common, large, hyaline, membranous
sac, about 1-24" in diameter, and contain-
ing a number of ovoid cells 1-7000 to
1-5000" in diameter, of a green or red
colour.

B. Braunii. In lakes.

BIBL. Kutzing, Sp. Alg. p. 892 ; Raben-
horst, Fl. Alg. iii. p. 42.

BOTRYOCYSTIS,Kiitzing.— Described
as a genus of Palmelleae
(Confervoid Algae) found
in stagnant fresh water,
but apparently forms re-
lated to Volvox. See VOL-

Fig. 76.

BIBL. Kiitzing, Sp. Alg.
p. 208; Tab. Phyc. pi. 9
and 10; Braun, Verjiln-
ffuna, &c. p. 170 (Ray
Soc. 1853).

BOTRYOSPO'RIUM,
Corda (Stachylidium,
Fries). — A genus of Mu-
cedines (Hyphomycetous
Fungi) allied to Botrytis,
but distinguished by the

lateral position of the Spo- A fertile filament

riferous branches (fig. 76). *«££ £^£"

British species : Magnified 200 diain.

B. diffusum, Corda
(Stachylidium diffusum, Fr., Botrytis dif-
fusa, Greville), forms loose white tufts,' a

quarter of an inch high, on decaying her-
baceous plants, especially potatoes.

B. pulchrum, Corda (tig. 70), forming
mealy patches on living or decaying herba-
ceous plants.

BIBL. Corda in Sturm's Deutschl. Fl. iii. ;
Pi-achtfl. JEurop. Schimm. p. 39 ; Greville,
Sc. Crypt. Fl. t. 126. fig. 2 ; Currev, Qu.
J. Mic. Sc. v. p. 117.

BOT'RYTIS, Mich.— A genus of Muce-
dines (Hyphomycetous Fungi), among
which are found some of the commonest
moulds of decaying vegetable substances,
and some very important parasitic l\ir</i.
Corda separated the species with the fila-
ments continuous into a genus Peronospora
(fig. 77), from those with articulate fila-

. 77.

Fig. 78.

Botrytis (Peronospora). Botrytis.

Magnified 200 diameters. Magnified 200 diameters.

ments (fig. 78). Among the remaining
forms are distinguished species of varying
habit, separated by some authors under the
name of Polyactis and Haplaria. The Po-
tato-fungus and the Muscardiue of silk-
worms are species of Botrytis, as described
below; their natural history is further
treated of under the head of PARASITIC
FUNGI. The following have been described
as British species : —

B. (Haplaria, Lk.) grisea, Fr. Fertile
filaments simple or forked, grey, slender,
rather rigid, septate, with little heaps of
globose grey spores at the apices and sides.
On decaying vegetables, usually on Spar-
ganium and allied plants. Corda, Ic. Fmui.
i. pi. 4. fig. 246.

B. (Polyactis) cinerea, Pers. Fertile fila-
ments gregarious, almost simple, cinereous,
soon strangulated, with white spores at-
tached hei e and there. Not uncommon on
stems of herbaceous plants.

BOTRYTIS.

BOTPtYTIS.

B. (Polyactis) cana, Schmidt. Fertile
filaments cinereous or whitish, branched at
the apex ; spores large, oval. On rotting
stems and leaves. Mucor racemosus, Bul-
liard, t. 504. fig. 7.

B. (Polyactis) vulgaris, Fr. (fig. 263).
Fertile filaments grey, divided at the apex
into lobe-like branches, on which are col-
lected the globose minute spores. Common
on rotting plants. B. acinorum, Pers. Fre-
senius, Beitr. z. Myc. i. pi. 2 (?). Polyactis
vulyaris, Nees, Syst. fig. 57.

B. vera, Fr. Fertile filaments grey,
branched above, forming spikes about the
slender apices. On decaying substances,
fungi, &c. Mucor Botrytis, Bolton, pi. 132.
fig. 3.

B. crustosa, Fr. Fertile filaments white,
simple, trifid and verticillate ; spores glo-
bose, terminal. On stems and leaves.

B. citrina, Berk. Mycelium white ; fer-
tile filaments erect, articulated, branched ;
branches subcymose, and, like the obovate
spores, lemon-coloured. On dead branches
of cherry-trees. Berkeley, Ann. N. H. i.
p. 262, pi. 8. fig. 12.

B. terrestris, Pers. Fertile filaments
white, quaternately divided at the tips, each
tip bearing a single globose spore. On rot-
ten sticks. Berk. I. c. pi. 14. fig. 24; Sta-
cliylidium terrestre, Grev. Sc. Crypt. Fl.
pi. 257.

B. Jonesii, Berk, and Br. Fertile fila-
ments erect, fawn-coloured, branched above ;
branches and branchlets divergent, mostly
opposite, the last fasciculated, the centre
always sterile and very acute ; spores round-
ish, spinv. On dung. Ann. N. H. 2 ser.
xiii. pi. 15. fig. 12.

B. Tilletii, Desm. Fertile filaments
branched, fulvous; branchlets very short,
whorled ; spores subglobose. On mosses
and various leaves. Desmaz. Crypt. Exs.
fasc. v. No. 226; Ann. d. Sc. Nat. 2 ser. x.
308.

B. (Peronospora) urticce, Libert, MSS.
(Berk.). Fertile filaments greyish lilac,
loosely divided above ; branches forming
an acute angle ; extreme branchlets simple
or forked, sometimes curved, rarely inflated ;
spores large, ovate, apex papilliform. On
nettle-leaves. Berk. Ann. N. H. ser. 2, vii.
p. 100.

B. {Peronospora) parasitica, Pers. Fer-
tile filaments white ; Branches ramulose ;
spores very large, globose. Caspary has
found here cysts containing minute spores
(sporidangid). On Ouciferae (turnips, cab-

s, &c.). Berkeley, J. Hort. Soc. i. pi. 4
fig. 26; Corda, Ic. Fung. v. pi. 2. fig. 18
Mucor Botrytis, Sowerby, pi. 359.

B. (Peronospora) effusa, Greville. Fertile
filaments purplish-grey, branched above ;
branches short, divaricate; spores large,
oval. Frequent on the lower face of leaves
of spinach.

B. (Peronospora} curta, Berk. Fertile
filaments simple, abbreviated, denticulate
at the tips, grey-brown; spores oval. On
Anemone nemorosa. Berk. Ann. Nat. Hist.
I. c. pi. 8. fig. 13.

B. (Peronospora) destructor. Fertile fila-
ments grey, erect, scarcely septate ; branches
alternate, the last forked, hooked, and diva-
ricated; spores obovate, much attenuated
at the base. Very destructive on species of
Allium (onions &c.). Berk. Ann. Nat. Hist.
vi. p. 436, pi. 13. fig. 23.

B. (Peronospora) Arenarice, Berk.
White; fertile filaments dichotomous
above, divaricate-forked, not hooked at the
tips ; spores ovate. On the leaves of Are-
naria trinervis. Berk. J. Hort. Soc. i. p. 31.
pi. 4. fig. 22.

B. (Peronospora) Vicice, Berk. White ;
fertile filaments sparingly branched, elon-
gate ; branchlets bifid , not hooked ; spores
obovate, apiculate. On common Vetches
(a distinct species, purple, is said to grow
on peas). Berk. /. c. pi. 4. fig. 23.

B. (Peronospora) arborescens, Berk.
White ; fertile filaments very much branched
above, di-trichotomous, somewhat forcipate
at the apex; spores smallish, subglobose.
On common red-poppy leaves. Berk. I. c.
pi. 4. fig. 24.

B. (Peronospora) ganglioniformis, Berk.
White, in patches ; fertile filaments branched
above ; branchlets curved, dilated in gang-
lioid thickenings below the tips ; spores
small, subglobose. On lettuces. Berk. I. c.
pi. 4. fig. 25. B. geminata, Unger, Bot.
Zeit. v. pi. 6. fig. 9. Bremia lactucce. Regel.
Bot. Zeit. 1843, i. p. 665, pi. 3 B.

B. (Peronospora) macrospora, Ung. Fer-
tile filaments erect, several from the same
point, white, branched above ; spores very
large, elongate-pyriform. On leaves of pars-
nips and other Umbelliferae. Unger, Exan-
tlieme, pi. 2. fig. 14 B.

B. (Peronospora) infestans^ Montagne
(PI. 26. figs. 5, 6). the Potato-fungus.
This grows in tufts on the lower surface of
the leaves, and also on the tubers of the
potato, forming white mealy spots. The
mycelium ramifies in the intercellular pas-

BOTRYTIS. [ 11

§ages of the leaves, and sends out the fertile
filaments from the stomata, so that these
appear scattered among the hairs of the
epidermis; they are usually about 1-30"
high upon the leaves, branched at the apex,
septate and white. The 2 to 6 branches are
erecto-patent, acute, virgate, nodose from
numerous eliptical thickenings. The spores
in large specimens are at first globular-
ovoid, then elliptical, and finally somewhat
of the shape of a gourd-seed, with a sub-
apiculate mamilla at one end, very shortly
pedicellate at the other, of the same colour
as the filaments, chiefly white, densely
filled with sporules enclosed in an endo-
spore, about 1-800" long, 1-1200" thick.
These sporules have been shown by De
Bary to be zoospores when fully developed,
moving about by means of two cilia.
Besides the normal spores, there are resting-
spores in many Peronosporce, which have
been described by the same author in Ann.
d. Sc. N. 1863, xx. p. 10. Artotrogm of
Montagne is probably the resting-spore of
Peronospora infestans. Berkeley, Jn. Hort.
Soc. i. 30, pi. 2-4. figs. 4-19. Botrytis
Solani, auct., var. B. fallax, Desmazieres.
B. devastatrix, Libert ; Morren, Ann. de la
Soc. de VAg. de Gand, 1845, p. 287 ; Pero-
nospora trifurcata, Unger, Bot. Zeit. v. 314,
pi. 6. tigs. 1-6; W. Smith, M. M. J. 1875,
xiv. 110 (figs.).

Botrytis Bassiana, Balsamo, is the fungus
growing in the bodies of silkworms, causing
the disease called Muscardine, which some-
times produces most extensive destruction
in the districts where they are cultivated.
A figure of it is given by Mr. Berkeley in
the paper on the Potato-fungus referred to
above. Many papers on it exist in the
ComptesRendus; and the whole history, with
figures, will be found in Robin's Vegetaux
Parasites, p. 560.

Botrytis lateritia, Fr., not uncommon in

the hollows of decaying potatoes, beet-root,

&c., appears to be a form of Acrostalagmus

parasitans, Corda. See ACROSTALAGMUS.

The genus Botrytis, like many other

genera, has been divided and subdivided

till the genus itself has almost vanished.

It is restricted in the ' Outlines of British

Fungolo^y ' to those species which have

septate, hyaline or coloured threads, with

terminal spores, as B. Tilletii, citrina,Jonesii,

and terrestris. Several of the so-called

species are states of Ascomycetous Fungi.

See Tulasne, Carpologia, vol. iii.

BIBL. As given under the species. Fries,

| BRACHION^EA.

Summa Veget. p. 490; Berkeley, Crypt. Bot.
p. 307.

BOUGAINVIL'LIA, Lesson.— A genus
of marine Hydroid Zoophytes, family
Atractylidse.

Char. Stem branched, rooted by a fili-
form stolon ; polypes fusiform ; a single
wreath of filiform tentacles around the base
of the conical proboscis. 3 British species.
BIBL. Hiacks, Hydr. Zooph. p. 108.
BOWERBAN'KIA, Farre.— A genus of
Infundibulate Polyzoa (Bryozoa), of the
suborder Ctenostomata, and family Vesicu-
lariidae.

Distinguished by the matted and creeping
or erect and irregularly branched polypidom
(polyzoarium), the tubular densely clus-
tered cells, the eight to ten tentacles, and
the strong gizzard.

B. imbricata (PI. 18. fig. 19), the only
species, has the cells ovate or ovato -cylin-
drical, in dense clusters irregularly scattered
on the polypidom.

Parasitic on other Polyzoa, Polypi, and
Algae. Polypidom in the young state creep-
ing and matted, and formerly regarded as a
distinct species (B. densd) ; in the adult
condition forming bushy confer void flaccid
tufts, an inch and a half high, much and
irregularly branched. Branches smooth,
transparent and hollow, cells aggregated on
one side.

It forms a favourable object for the study
of the structure of the Polyzoa, on account
of its transparency.
Four other species.

BIBL. Johnston, Br. Zooph. 377 ; Farre,
Phil. Tr. 1837, 391 ; Gosse, Mar. Zool. ii.
p. 21; Hincks, Polyzoa, 518; Repiachoff,
Zool Anz. ii. 1879, 660 (Jn. Mic. Soc. 1880,
iii. 238 : embryol.).

BOX. — The wood of the box-tree, Buxus
sempervirens, L. (Nat. Ord. Euphovbiaceae,
Dicotyledon), is remarkable for its hardness,
offering a great contrast to that of Bombax
and the like. See WOOD.

BRACHION^E'A.— A family of Rota-
toria.

Char. A carapace (testula) present ; rota-
tory organs two, simple.

The rotatory organ sometimes appears
to consist of five parts, three median and
two lateral. The two larger lateral ones
only are true rotatory organs, the cilia
of the median ones remaining extended
without motion during the action of the
others. The carapace resembles that of a
tortoise.

BRACHIONUS.

BRANCHIPUS.

Genera :

Eye-spots absent ; foot forked

c foot absent ...... Anureea.

Fig. 79.

3 \ foot styliform .. Pterodina.

See HYDROCORA and DIPODINA.

BRA'CHIONUS, Hill.— A genus of Ro-
tatoria, of the family Brachionaea.

Char. A single eye-spot at the back of
the head ; foot forked.

The anterior margin of the carapace is
furnished with teeth, as in some species is
the posterior margin also.

B. amphiceros (PI. 43. fig. 8). Carapace
smooth, furnished both at the anterior and
posterior margin with four teeth ; aquatic ;
length 1-70".

B. rubens. Carapace smooth, with six
acute teeth in front, and rounded posteriorly ;
body reddish ; aquatic ; length 1-50" : teeth,
PL 43. fig. 9.

Eleven other species have been described;
some of them freshwater, others marine.

BIBL. Ehrenb..Zw/.; Dujardin, Inf.; Gosse,
Ann. N. H. 1851, viii. p. 202; Cbhn, Sieb.
$ Kollik. Zeit. vii. p. 459.

BRACHYCLA'-
DIUM, Corda.— A genus
of Deinatiei (Hyphomy-
cetous Fungi), not se-
parated by any marked
characters from DEN-
DRYPHIUM ; forming a
delicate mould on dry
stems of herbaceous
plants. The filaments
and branches are formed
of squarish cells, swollen
so as to produce a moni-
liform appearance, the
walls being thick and
coloured.

The so-called species ciliatum.

are probably Stages of An erec-t filament with
A Qr»nTnvpptnn<» "Punon fertile branches.

ASCOmycetOU -rungl. Magnified 200 diame-

B. pemctllatum, C orda, tera.

is said to extend over
stems, sometimes in tracts a foot long ; the
filaments and branches are blackish, the
spores white (fig. 79).

B. Thomasinum has been found in amber.

BIBL. Corda, Ic. Fung. ; Fries, Summa
Veg. p. 504.

BRACHYCO'LUS, Buckton.— A genus
of Aphidse.

B. stellarifB. Body mealy, very long and
narrow. On Stellaria holostea and Holcus
mollis.

Brachycladium peni-

BIBL. Buckton, Aphides (Ray Soc.), ii.
p. 146.

BRA'CHYODUS, Nees.— A genus of
Leptotrichaceous Mosses, separated from
Gymnostomum or Weissia of some authors.

BIBL. Wilson, Bryol. Brit. p. 52.

BRACHYSTE'LIUM, Reichb.— A ge-
nus of Orthotrichaceous Mosses.

Brachystelium polyphyllum, Hsch., =
Ptychomitrium polyphyllus, Br. and Sch.

BIBL. Wilson, Bryol. Brit. p. 173.

BRACHYTHE'CIUM, Br. and Sch.,=
HYPNTJM.

BIBL. Wilson, Bryol. Brit, p, 337.

BRA'DYA, Boeck.— A genus of Ento-
mostraca (Copepoda).

B. typica. Anterior antennae very short,
7-jointed. Scilly Isles.

BIBL. Brady, Copepoda (Ray Soc.~) ii.
p. 16.

BRADYCINE'TUS, Sars.— A genus of
Entomostraca, of the order Ostracoda (sec-
tion Myodocopa) and family Cypridinidse.
Characterized by the 2-branched lower
antennae, and the one pair of feet. B. brenda
= Cypridina brenda, Baird ; B. Macandrei
= Gyp. Mac. B.

BIBL. Brady, Linn. Trans, xxvi. p. 466.

BRAIN. See NERVES.

BRAI'NEA, Hook.— A genus of Gram-
mitideae (Polypodiaceous Ferns), with con-
tinuous sori along transverse veins near
the midrib, produced along the veins to-
wards the edge of the frond.

The single species, B. insignis, is found at
Hong Kong &c.

BIBL. Hooker, Syn., p. 390.

BRAN. See CORN.

BRAN'CHLE.— This term is synonym-
ous with gills. The latter term, however,
is usually applied to the aquatic respira-
tory organs of fishes, whilst those of other
animals retain the name of branchiae. Their
structure is described with that of the re-
spective classes in which they occur. See
also EPHEMERA and LIBELLULIDJE.

BRAN'CHIPUS, Schaeffer (Chiroce-
phalus). — A genus of Entomostraca, of the
order Phyllopoda, and family Branchipo-
didae.

Char. Abdomen prolonged in the form
of a tail, composed of nine segments or
joints, the end joint with two well-deve-
loped plates or lamellar appendages ; supe-
rior antennae, in both sexes, slender, fili-
form, and many-jointed; inferior antennae
in the male large, curved downwards, two-
jointed, furnished at the base with fan-

BRAND.

[ 120 ]

BRONCI10CERCA.

shaped and digitiform appendages ; in the
female stout, short, some what acute, slightly
curved, and not furnished with appendages
at the base.

B. stagnate (PL 20. fig. 3). An inch in
length ; 'tinged with red.

This beautiful animal is found in stagnant
water, as the ditches and deep cart-ruts on
the edges of woods and plantations.

B. rubricaudatus, Kl. Ovarian sac and
tail-fork red ; the former long, cylindrical,
terminating in a curved prickle.

In rain-water, at Kossier (Red Sea).

BIBL. Baird, Brit. Entom. p. 39 ; Klun-
zinger, Sleb. fy Roll. Zeitsch. xvii. p. 23.

BRAND. — A disease of Cereal Grasses
and other plants, depending on Fungi. See
BLIGHT.

BREAD.— The interest of the micro-
scopic examination of bread depends chiefly
on the impurities it may contain, or the
peculiar Fungi-development in it during
decay. The commonest intentional adul-
teration of bread is the addition of mashed
potatoes to the flour ; but it must be re-
membered, that potato-yeast is sometimes
used to produce the fermentation of the
dough. The cells of the potato are readily re-
cognizable in bread after the starch has been
dissolved and washed away. The adul-
teration of the flour with other meals, as
corn-flour, rice, beans, &c., is easily ascer-
tained before it is made up ; but the baking
greatly affects the form of the starch-gra-
nules. See STARCH.

The spores of the parasitic Fungi of wheat
(UREDINEI, USTILAGINEI), pollen -grains,
and other vegetable bodies are occasionally
met with as accidental impurities, and are
present in large numbers in inferior and
" damped " flours.

The fermentation of bread depends upon
the development of the YEAST fungi in the
dough : an account of this will be found
under that head, and FERMENTATION.

Mouldy bread presents various microscopic
fungi in a mature condition, some evidently
the fruit of the yeast-plants, PENICILLIUM,
Mucon, &c. ; others, like the so-called
' blood on bread/ appear to be peculiar
states of the vegetative structure of the
same Fungi.

BIBL. That of ADULTERATION ; and
Coulier, Manuel fyc. ; Robin, Micr. p. 922.

BRET'TIA, Dyster.— A genus of Chei-
lostomatous Polyzoa (Bryozoa), family Eu-
cratiidse. Two species : found between tide-
marks, and in di edgings.

p. 27; Dyster,

BARTRA-

Fig. 80.

Briarea penicillata.

Magnified 200 dia-
meters.

BIBL. Hincks, Polyzoa,
Qu. Mic. Jn. 1858, vi. p. 260.
BREUTE'LIA, Br. and Sch.,

MIA.

BIBL. Wilson, Bryol. Brit. p. 283.

BRIA'REA, Corda.— A genus of Muce-
dines (Hyphomycetous
Fungi), nearly related to
Pemcilliunij Aspergilius,
and Monilia, distinguished
from the first and last by the
moniliform rows of spores
arising, directly, in a ter-
minal tuft, while the erect
fertile filament is not ex-
panded into a capitulum
to bear them, as is the case
in Aspergittus. British spe-
cies : —

Briarea penicillata (fig.
80), (Monilia,¥ne&,As})er-
</ illus, Greville). The erect
filaments are simple and
geuiculate, the spores hya-
line, forming long nodding
moniliform rows. It is of dark grey colour,
and is found on damp grass, mouldy hay,
straw, &c.

BIBL. Corda, Ic. Fung. v. 16, and in
Sturm, Deutschl. Flor. ii. pi. 6 ; Greville,
Sc. Crypt. Fl. t. 32 ; Berk., Hook. Br. Fl.
345.

BRIGHT WELLIA, Ralfs.— A genus of
Diatomaceae.

Char. Valves disk-shaped, with a large
granulated centre, separated from a broad
punctate limb by a ring of oblong cells.

B. coronata, Mic. Tr. viii. p. 95, pi. 5.
f. 6; B. elaborata, ibid. 1861, i. p. 73;
B. Johnsoni, ibid. 1866, vi. p. 4.

BIBL. Ralfs, Pritchards In/us, p. 940.

BRINE- WORM. See ARTEMIA.

BRISTLE. See HAIRS.

BROMELIA'CE^E.— A family of Mono-
cotyledons (Flowering Plants), of which the
Pine-apple, Ananas or Ananassa, is the
most familiar example. This is interesting
microscopically from the scurfy character of
the epidermis of the leaves, dependent on
peculiar cellular scales. The cells of the
epidermis are of very elegant form (PI. 47.
fig. 15) ; and the fibres of the leaf are manu-
factured into very fine muslin. See SCALES,
EPIDERMIS, and FIBRES.

BRONCHI. See LUNGS.

BRONCHOCER'CA.— Monocerca with
the caudiform foot cleft at the end. Five
species have been described ; but it appears

BROOKE'S APPARATUS.

BRYOBIA.

that tliey do not differ by well-marked cha-
racters from the species of Monocerca.

BIBL. Werneck, Ber. Berl. Ak. 1841,
377.

BROOKE'S APPARATUS. INTRO-
DUCTION, p. xxi.

BRUCHIA'CE^E.— A family of inoper-
culate Acrocarpous Mosses, gregarious or
Cfespitose and terrestrial, in which the fruit-
stalks sometimes appear lateral, through
arising from innovations. The stems dwarf,
either simple or branched by innovations ;
the leaves lanceolate or awl-shaped from a
more or less oval base, composed of paren-
chymatous cells, larger and sometimes lax
at the base of the leaf, smaller and squarish
toward the apex, and furnished with a flat-
tened broad nerve (fig. 49), and standing up
like bristles ; the perichsetial leaves broader
at the base and sheathing j all of firm mem-
branous character, shining and smooth.
Capsules oval or globose, mostly straight-
beaked (fig. 50). British genera : —

Archidinm. Calyptra completely en-
closing the (globose) capsule, bursting above.
Inflorescence monoecious, bud-shaped.

Astomum. Calyptra dimidiate. Capsule
equal. Inflorescence either monoecious,
gemmif orm and axillary, or with the anthe-
ridia and archegones together.

BRU'CHUS, Linn.— A genus of Coleo-
pterous Insects.

B. pisi is a common small beetle ; black,
mottled with white. The larva feeds upon
peas. Several other species.

BIBL. Stephens, Brit. Coleopt. p. 264 ;
Boisduval, L'Entomol. Horticole, p. 157.

BRU'CIA. See ALKALOIDS.

BRYA'CE^E.— A family of operculate
Mosses, acrocarpous, or by innovation pleu-
rocarpous, with lan-
ceolate, oval, round, Fig. 81.
or spathulate leaves,
composed of cells pa-
rallelograrnmic below,
rhomboidal - paren-
chymatous above,
more or less dense,
with much chloro-
phyll or a persistent
primordial utricle, or
at length empty, very
smooth. Capsule more Mielichoferia nitida.
or less Pear-shaped, Teethfromther.8tome

Clavate, Oval or cylin- Magnified 150 diameters.

drical, with a hemi-
spherical or conical operculum, erect, nod-
ding or pendulous. External peristome,

when present, soft, lamellose, internal
membranous. British genera : —

Mielichoferia. Calyptra conical-dimi-
diate, split at the side. Peristoine wanting
or simple, then of sixteen equidistant, fili-
form, flattish, articulated pale teeth, some-
times placed on a short, sulcate, reticulate
basilar membrane (fig. 81). Capsule late-
ral, with a double annulus.

Orthodontium. Calyptra smallish, hood-
shaped, fugacious. Peristome arising below
the orifice of the capsule, double j external :
of sixteen lanceolate-subulate teeth, like
those in Bryum j when dry, deflexed below
the orifice of the capsule, when moistened,
erect; internal: cilia alternating with the
external teeth, half as long or about equal,
filiform, from a short, somewhat keeled
membrane. Capsule annulate or exannu-
late, with a longish collum.

Bryum. Calyptra dimidiate, smallish,
hood-shaped. Peristome double (fig. 82) ;

Fig. 82.

Bryum intermedium.

A portion of the peristome.
Magnified 150 diameters.

external of sixteen lanceolate, soft, yel-
lowish equidistant teeth, flat on the back
and transversely trabeculated, with a flexu-
ous longitudinal line in the middle, lamel-
late within, hygroscopic; internal a large
delicate membrane with sixteen keels, pro-
duced into more or less perfect lanceolate
teeth, often with intermediate cilia, some-
times without. Capsules mostly annu-
late.

BIBL. See MOSSES.

BRYO'BIA, Koch.— A genus of Aca-
rina, family Trombidina.

Char. Legs 6-jointed ; fore legs longest ;
eyes near the hind angles of the cephalo-

BRYOPSIS.

[ 122 ]

BUDS.

thorax ; abdominal margin studded with
short, somewhat triangular sparse papillae.
B. speciosa.

BIBL. Koch, Uebersicht, 61; Murray,
EC. Ent. 117.

BRYOP'SIS, Lamouroux.— A marine
genus of Siphoneae (Confervoid Algae), of
which the British species form beautiful
green, somewhat elastic, feathered silky
tufts, from 1 to 4" high upon rocks or upon
other Algae, in tide-pools. The whole axis
and proper branches of each plant consist of
one large ramified cell, the cavity being
continuous throughout, the membranous
wall rather thick, and somewhat gela-
tinous externally ; the branches are naked
below, but clothed above by small ramuli,
arranged like leaves, distichously, spirally,
or irregularly. The main axes and branches
grow indefinitely by development of the
apices; the ramuli are limited in their
development, and they are ultimately shut
off by septa, at last falling off by the cir-
cular rupture of their wall, just above their
point of origin.

When examined early, the ramuli are
found to have their walls lined with largish
elliptical green grains, each of which has at
first a round light central body, colourable
blue by iodine when fully formed (starch-
corpuscle). The branches exhibit the phe-
nomenon of reproduction, in irregular order,
in the following way. The green bodies on
their walls multiply by subdivision, and
increase in size and number until they com-
pletely fill the tubular cavity of the ramule,
pressing upon one another so as to form a
compound dark-green mass. A peculiar
swarming movement is next observed in
the green bodies, which increases more and
more; and, the parent tube opening by a pore
near its apex, the green bodies escape as
elongated pear-shaped zoospores or active
gonidia with cilia, according to Thuret,
two and four in B. hypnoides, only two in
B. plumosa. The successive emission of
the gonidia from the various tubes of one
plant occupies several days.

After the gonidia have come to rest, they
acquire a spherical form, and gradually in-
crease in size ; at the end of a month or six
weeks their diameter is twice or thrice the
original dimensions ; and then they begin to
elongate into a tube similar to the parent.
Agardh found them elongate, either in one
direction or in two, at first ; but one end
soon swelled into a thickened organ of
attachment, while the other began about

spe-

the sixth week to branch. British
cies : —

B. plumosa, Huds. (PI. 4. fig. 19). Deep
green, 1 to 4 inches high, more or less
branched ; the branches pinnated with sub-
opposite distichous or rarely irregular ra-
mules. Harvey ,Afar. Alga, 2nd ed. pi. 24 B ;
Phycol. Brit. pi. 3 ; Greville, Alga, pi. 19 j
Engl. Bot. (Ulva plumosa), 2375.

B. hypnoides, Lamour. Yellow-green,

2 to 4 inches high, more slender and more
branched, branches repeatedly divided, ra-
mules irregularly scattered, somewhat pin-
nate, more or less dense. Harvey, Phyc.
Brit. pi. 119.

BIBL. Systematic, as above, and Kiitzing,
Sp. Alg. p. 490 ; Physiology, &c., Agardh,
Ann. d. Sc. Nat. 2 s<5r. vi. 200, pi. 12; Na-
geli, Zeits. iviss. Bot. 1844-46 (Ray Soc.
1845, 269, pi. 6. figs. 11, 12; 1849, 97, pi. 2.
figs. 1-3) ; Neu. Algen-Systeme, 1847, 171,
pi. 1. figs. 44-56 ; Thuret, Ann. d. Sc. N.

3 se>. xiv. 8, pi. 16. figs. 1-6 ; Braun, Verj.
137 (Eay Soc. 1853, p. 120) ; Pringsheim,
Monatsber Berl. Akad. 1871 ; Sachs, Bot.
275.

BRYOZO'A. See POLYZOA.

BRY'UM, Dill.— A genus of operculate
Mosses, usually acrocarpous, containing a
large number of British species, even in its
restricted condition.

Among the most common of these are
B. nutans (fig. 467), cernuum, intermedium,
capillare, caspiticium, &c. Many of the
older species are now included under
MNIUM.

BIBL. Wilson, Bryol. Brit. p. 221.

BUC'CJNUM, L.— B. undulatum, the
common Whelk. The tongue forms an
interesting microscopic object.

BUDS. — The buds of plants form inter-
esting objects of microscopic investigation
on many accounts, — first, in tracing the de-
velopment of the organs, and also of the
tissues of which these are formed; secondly,
on account of certain temporary structures
which they exhibit. The thick epidermis
of the scales of the winter-buds of ordinary
trees, as of the ash, &c., is a very favour-
able object for sections to show the charac-
ter of this tissue when highly developed.
The internal soft scales and young leaves of
very many of these winter-buds, as well as
other buds of herbaceous plants, are clothed
with glandular hairs, which disappear when
the buds are expanded ; and these often
afford advantageous material for studying
cell-development. See GEMMAE.

BUG.

[ 123 ]

BULBOCH^ETE.

BUG. See CIMEX.

BU'GULA, Oken (Cellularia part, John-
ston).— A genus of Infundibulate Polyzoa
(Bryozoa), of the suborder Cheilostomata,
and family Bicellariidse.

Distinguished by the elliptical closely
contiguous cells in two or more rows, the
very large orifice with a simple not thick-
ened margin, and the stalked, jointed, fre-
quently blue or red avicularia.

B. jlabellata. Cells in many rows, ob-
long, truncate at ends, with one or two
spines at upper angles ; orifice extending to
the base ; avicularia on the sides of the cells
capitate, surface smooth ; ovicells cucullate,
with a very wide orifice.

B. avicitlaria (Cellularia avic., Johnston).
Cells in two rows, elongate, contracted
below ; orifice not reaching quite to the
base, obovate ; with two spines on the outer
side, and one on the inner above ; avicularia
lateral, capitate, surface granular or areo-
late ; ovicells superior, subglobular : orifice
small. Deep water.

B. plumosa. Cells elongate, narrowed
below, with a spine at upper and outer angle ;
orifice as wide as the cell above, elliptical
below; avicularia capitate, close to outer
margin of the orifice ; ovicell superior, glo-
bular.

B. Murrayana (Flustra Mur., Johnst.).
Cells in many rows, narrowed about the
middle and below ; orifice oval, with one to
four incurved marginal spines on the outer
and one on the inner edge ; a strong hollow
spine on each side of the top of the cell, and
a capitate avicularium on the front of some
of the cells below the orifice. Very rare.

BIBL. Busk, Mar. Polyzoa (Br. Mm.\
43 ; Johnston, Br. Zooph. ; Hincks, Potyzoa,
73.

BULBOCHJE'TE, Ag.— A genus ofCE-
dogonieae (Confervoid Algse), distinguished
by the branched habit, and by the cells re-
sembling bristles with a bulbous base situ-
ated at the tips of lateral shoots. They
form villous tufts 1-4 to 1-2" high on fresh-
water plants in lakes and pools.

The cells of the main filament multiply
in the same way as those of (EDOGONIUM:,
under which head the process is minutely
described. The parent-cell breaks by a cir-
cumscissile dehiscence to allow the expan-
sion of the two new cells. The bristles which
are formed at the upper ends (alternately
on each side of the filament, fig. 83) like-
wise break out from a slit in the cell from
which they arise. The bristle is sometimes

Fig. 83.

sessile on the cell from which it arises ;
sometimes multiplication takes place at its
base, so that one or more cells are inter-
posed ; the bristle is always the oldest part
of the branch.

These plants are
multiplied by zoo-
spores, and by rest-
iug-spores formed
after fertilization
by the contents of
antheridial cells.
The zoospores are
formed from the
whole contents of a
globular or oval
cell produced be-
tween the bristle- Bulbochsete setigera.
cell and the cell on Portion of a filament ^ a

which it IS attached, sporiferous cell.

Which dehisces by Magnified 150 diameters.

a circular slit, causing the upper part with
the bristle to separate, and allowing the
single zoospore, crowned by a wreath of
cilia (as in GEdogonium}, to escape into the
water, where it moves actively for a time,
acquires a cellulose coat, and then germinates
into a new filament. We have not space to
give the details of the development of the
parent-cell of the zoospore, which, however,
are very interesting.

The resting-spores are formed, in the first
place, somewhat in the same way and in the
same situations as the zoospores; but the cell-
contents do not escape. An orifice is formed
in the wall of the parent-cell, through which
the spermatozoids coming from the anthe-
ridia penetrate. The spore-mass then be-
comes encysted ; and its contents are changed,
the green colour arising from the presence
of chlorophyll giving place to a brown tint.
The resting-spore ultimately escapes by the
rupture of the parent-cell (oogonium, Prings-
heim) ; and in its germination (in the fol-
lowing season) the contents are developed
into four zoospores, which escape from the
spore-membrane and grow up singly into
new plants (PI. 5. fig. 22).

The history of the antheridia of the CEdo-
gonieae is somewhat complicated. In the pre-
sent genus, a few short cylindrical cells are
developed underneath the bristle-cell, either
on special branches or on the sporangial
branches, between the parent-cell of the
spores and the bristle. These cells break
by circumscissile dehiscence, and discharge
their contents in a form exactly resembling
the vegetative zoospores, but much smaller.

BULBOTRICHIA.

[ 124 ]

BURSARINA.

These ultimately come to rest, and com-
monly attach themselves to germinate upon
the walls of the parent filament, often on
the outside of the mother cell of the spore.
When they germinate, they become short
filaments composed of one, two, or several
cells, in each of which is developed one or
two spermatozoids, which are minute glo-
bular active bodies with a wreath of cilia,
almost colourless, but in other respects re-
sembling the much larger zoospores. These
spermatozoids escape by the cells breaking
across, and have been observed to enter the
orifices in the walls of the parent-cells of
the spores and effect the fertilization.

Prmgsheim has described a number of
species, characterized by the form of the
sporange and the unicellular or multicellu-
lar condition of the antheridial plants, and
by the relative dimensions of the organs.
We are not assured of the value of these cha-
racters, and confine our list to one species.

B. setigera, Ag. (fig. 83), is a common
plant, and is variable in the relative length
and diameter of its cells, on which ground
Kiitzing has separated a B. minor, where
the diameter is equal to or greater than the
length. Hassall, Alg. pi. 54. figs. 1-4 j Dill-
wyn, Conferv. pi. 59.

B. Pringsheimiana, Archer, Qu. Mic. Jn.
1866, p. 122.

Rabenhorst describes 16 species.

BIBL. Alex. Braun, Verjiing. (Hay Soc.
1853) ; Hassall, Ann. N. H. xi. 36 ; Alg.
209, pi. 64; Decaisne, Ann. d. Sc.Nat.2 se"r.
xvii. 335, pi. 14. fig. 5 ; Kiitzing, Sp. Alg.
429; Pringsheim, Berlin Ber. 1855 (Ann. N.
H. ser. 2. xv. 346; Qu. Mic. Jn. iv. 131,
1856) ; Jahrb. f. iviss. Bot. i. 11, 1857 ; De
Bary, Mm. Senckenberg, 1856, 29 ; Raben-
horst, Fl. Alg. iii. p. 357 ; Sachs, Bot. 281.

BULBOTRICH'IA, K.— A doubtful ge-
nus of AlgaB.

Char. Filaments indistinctly jointed,
colourless, subcartilaginous, branched ;
branches bulbous at the base, tumid at the
apex, forming sporangia.

B. botryoides. Forming a hoary-green
powdery stratum j sporangia green. On
roofs.

B. peruana. On rocks.

BIBL. Kiitzing, Tab. J%c.iv. p. 22; Ra-
benhorst, Fl. Alg. iii. p. 374.

BULIMTNA, D'Orb. — An important
group of Foraminifera, so called from their
Bulimine shape, due to an increasing and
spiral series of one, two, and even three
chambers, close-set, with their apertures

towards the umbilical axis. The aperture
is an infolded notch of the septal face, and
usually oblique. The shell hyaline in the
young state, coarser in the adult. Many
fossil specimens are arenaceous ; these come
under Atavophragmium, Reuss. The va-
rieties are infinite, both recent and fossil,
and the names numerous. The oldest is
found in the Trias. B. Preslii, Reuss, is
typical. B. pupoides (PI. 23. fig. 46) is a
common Atlantic form.

BIBL. D'Orb. For. Fos. Vien. 61 ; Wil-
liamson, Br. For. 61 ; Carpenter, Introd.
For. 194.

BUNT.— A disease of Cereal Grasses,
&c., depending on Fungi. See BLIGHT,
TILLETIA.

BURSA'RIA, Ehr.— A genus of Infuso-
ria, of the family Bursarina.

Ehrenberg described fourteen species.
They are mostly found in stagnant fresh
water ; some in the intestines of the frog,
Nais, &c.

B. vernalis (Panophrys, D., Frontonia, Cl.
& L.) (PI. 30. fig. 19). Body ovate-oblong,
turgid, green, rounded at each end, some-
what narrowed posteriorly, the mouth placed
behind the anterior third or fourth of the
body ; fresh wat. ; length 1-130 to 1-110".

B. ranarum (Opdlina ran.) (PI. 31. fig.
47). Body ovate, lenticular, compressed,
large, white, the dorsal and ventral surfaces
keeled, anterior part subacute, often trun-.
cate posteriorly, mouth inferior, near the
anterior pointed end; length 1-210 to 1-70".
In the intestines of the frog.

B. entozoon, Ehr., which is found in the
rectum of frogs, is Balantidium entoz. of Cl.
and Lachm.

Cl. and Lachm. admit only 1 species :

B. decora. Body urn-shaped, with a long
convolute nucleus, and very numerous con-
tractile vesicles, scattered through the par-
enchyma. Berlin.

The species of B. (Ehr.) are referred to
other genera.

BIBL. Ehrenb. Inf. ; Duj. In/us. ; Stein,
Infus. Entwickel. ; Clap, and Lachm. Inf.
p. 251 ; Kent, Inf. p. 574.

BURSARI'NA, Duj.— A family of In-
fusoria.

Char. Body very contractile, of variable
form, usually oval, ovoid, or oblong, ciliated
all over ; a large mouth with cirri forming
a row or part of a spire.

Claparede and Lachman divide the family
thus :—

BUSKIA.

[ 125 ]

BUXBAUMIA.

STENTORINA (subfamily). A carapace, at least at one period of life ; anus anterior.
Body not truncate in front.

Buccal spire borne on a narrow process Chcetospira.

Buccal spire borne on a broad bilobed membranous expansion freia.

Body truncated in front by a broad surface bearing the buecal cirri on its circumference Stentor.

BURSARINA (subfamily) proper. No carapace ; anus posterior.
Watch-glass organ absent.
No row of cirri within the buecal fossa.
Front not projecting.

Body truncated in front by an oblique surface with buecal cirri at its circumference Leucopkrys.

Body not truncate in front.

Anterior bundles of cirri absent from buecal fossa*
No cirri on the right side.

Body linear

Body not linear

Bordered with cirri on the right side also.
Body elongate, of uniform breadth

Body globular, narrowed in front
Buccal fossa very large, with two anterior bundles of cilia distinct from the buecal cirri

Fore part

projecting beyond the buecal fossa.
Fossa oblique

Fossa not oblique

Buccal fossa funnel-shaped, with a row of strong cirri

A watch-glass-shaped organ at the side of the mouth

Kent's arrangement differs from this, and
includes several new genera, 21 in all.

BLBL. Duj. In/us. ; Cl. and Lachrn. Inf.
p. 211 ; Kent, Inf. p. 574.

BUS'KIA, Alder.— A genus of Cteno-
stomatous Polyzoa (Bryozoa).

B. nitens. On Hydroida, &c.

BIBL. Hincks, Polyzoa, p. 531.

BUTTER.— The detection of the adulte-
ration of butter is rather a matter of che-
mistry than of microscopic investigation.
But Michels points out that the spurious
"butter (oleo-margarine) exhibits numerous
free stellate or feathery crystals, often also
fragments of animal tissues ; while true
butter presents a uniform appearance of
fatty globules, and is perfectly free from
any crystalline forms except those of chlo-
ride of sodium or common salt. (Michels,
Amer. Jn.Micr. 1878; Jn. Mic. Soc. 1878, i.
p. 378.)

BUTTERFLIES. See LEPIDOPTERA.

BUXBAUMIA'CE^E.— A familyof oper-
culated Acrocarpous Mosses, of very dwarf
stemless habit, arising from a minute tuft
of radical filaments (figs. 84, 86, &c.). The
leaves are small and flat, composed of few
minutish, hexagonal or polygonal paren-
chymatous cells, empty, destitute of chloro-
phyll (fig. 86). The capsule (fig. 87), seated
on an elongated, thick, fleshy and very
scabrous stalk, is more oblique than in any
other Mosses, very ventricose on one side,
obliquely erect on the other (dorsal) side,
cup-shaped at the base, articulated on its
stalk, fungoid in general habit, with an
obtusely conical straight operculum, and a

Spirosfomum.
Plagiotoma.

Eondylostoma.

Balantidium.

Lembadium.

Metopug.

, Frontonia,

Sursaria.

Ophryoglena.

peristome (fig. 93). Inflorescence monoe-
cious. Brit, genus :

BUXBAU'MIA, Hall.— A genus of Bux-
baumiacese (Acrocarpous Mosses), repre-
sented in Britain by B. aphytta, a plant of
remarkable character. The annulus, which
persists after the operculum has fallen, re-
sembles a third, outer circle of peristomal
teeth (fig. 93) ; the real external peristome is
closely applied upon the inner, which forms
a truncated cone, slightly twisted when dry.
When ripe, the wall of the oblique capsule
(fig. 88) gives way at one side, falls off and
exposes the spore-sac (fig. 89), which bursts
to discharge the spores. The columella
(fig. 94) is very large ; and the operculum is
attached to its summit. The antheridia are
oval cellular bodies opening by the separa-

Fig. 84.

Buxbaumia aphylla.

Fig. 85.

Fig. 86.

Fig. 84. A male antheridiiferous plant, magnified 40
diameters.

Fig. 85. An antheridium burst and discharging sper-
matpzoids, magnified 100 diameters.

Figs. 86,90, and 91. Archegoniiferous plant, indiffer-
ent stages, magnified 40 diameters.

BYTHOCYTHERE.

[ 126 ]

CABEREAD.E.

tion of the cells like teeth above, to emit
grumous masses of spermatozoids (fig. 85).

JB. indusiata has been found at Aboyne,
in Aberdeenshire, by Prof. Dickie.

BIBL. Bruch and Schimper, Bryol. Europ.
part i. ; Wilson, Bry. Brit. p. 198.

Buxbaumia aphylla.

Fig. 87. Fig. 88.

Fig. 89.

Fig. 87. A ripe capsule, magnified 15 diameters.

Fig. 88. A plant in which the capsule has burst and
lost the spore-sac, &c., magnified 15 diameters.

Fig. 89. Spore-sac exposed by removal of the wall of
the capsule, showing the filaments by which the spore-
sac is suspended within the latter ; magnified 40 dia-
meters.

BYTHOCYTHE'RE, Sars.— A genus of
Entomostraca (Ostracoda), fam. Cytheridse.

Distinguished by the toothed mandibles,
the 4-jointed lower, and the 7-jointed upper
antennae.

3 British living species : B. simpler, B.
constricta, and B. turgida.

BIBL. Brady, Linn. Tr. xxvi. pp. 393,
450.

BYTHOT'REPHES, Leydig.— A genus
of Entomostraca, ord. Cladocera, fam.
Daphniadae. Allied to Polyphemus and
Evadne.

B. longimanus. Caudal bristle two or
three times the length of the body. Found
in Scania.

BIBL. Leydig, Daphnid. 244; Ann. N. H.
1862, ix. p. 135.

Buxbaumia aphylla.

Fig. 90. Fig. 91. Fig. 92.

Fig. 92. A young fertile plant elevating its sporange
covered by the calyptra, magnified 15 diameters.

Fig. 93.

Fig. 94.

Fig 93. Mouth of capsule, with double peristome and
recurved persistent annulus ; magnified l.'O diameters.

Fig. 94. Columella with adherent operculum, both
capsule-wall and spore-sac having been removed;
magnified 60 diameters.

CABE'REA, Lamx. — A genus of Infun-
dibulate Polyzoa (Bryozoa), of the suborder
Cheilostoma'ta, and family Cabereadae.

Distinguished by the unjointed polypi-
dom, with narrow branches; the cells in
two or three rows, vrith large vibracula
(whips) or sessile avicularia at the back,
placed obliquely in two rows. Two British
species.

C. Hookeri ( CeUidaria Hook., Johnston).
Cells rounded, diverging, and projecting.
Rare.

BIBL. Johnston, Br. Zooph. 338 ; Busk,
Mar. Polyz. 37 ; Hincks, Polyzoa, 57.

CABE'READ^E.— A family of Infundi-

CABINET.

[ 127 ]

CALTCIUM.

bulate Polyzoa (Bryozoa), of tlie suborder
Cheilostomata.

Distinguished by the unjointed polypi-
dom, the narrow branches, the cells in two
or more rows, with vibracula (whips) or
sessile avicularia at the back. Genera :

Caberea. Back of branches covered with
large vibracula.

Amastigia. Vibracula absent. Not
British.

BIBL. Busk, (Brit. Mus.} Catal of Mar.
Polyzoa, 37 ; Johnston, Brit. Zooph.

CABINET for holding microscopic ob-
jects. See INTRODUCTION, p. xxiii.

C ACT A'CE^E.— A singular family of Di-
cotyledonous plants, especially remarkable,
microscopically, for the peculiar structure
of their wood-cells. See SPIRAL, FIBROUS
STRUCTURE, and WOOD.

BIBL. Schleiden, Anat. der Cacteen, 184 ;
Miquel, Ann. d. Sc. Nat. 2 ser. xix. 165.

CA'DIUM, Bail.— A genus of Rhizopoda,
fam. Actinophryina ?. Animal unknown.

Char. Shell siliceous (?), ovoid, with a
bent beak, and a circular aperture ; often
with a long curved tapering appendage at
the base, and with numerous meridian lines,
of which about twelve are visible at once.

C. marinum (PL 51. fig. 30). Soundings
in the sea of Kamtschatka, and the Gulf-
stream.

BIBL. Bailey, Silltman's J. 1856, xxii.
p. 3, pi. 1. f. 2 ; Wallich, M. M. J. i. p. 107,
pi. 3.

C AD 'MIUM.— Solution of the oxide or
carbonate of this metal in sulphuric acid,
when evaporated on a slide, yields disks or
circular aggregations of minute radiating
needles (circular crystals) of the sulphate,
which exhibit essentially the same pheno-
mena under the action of polarized light as
those of the oxalurate of ammonia. The
disks frequently exhibit irregular undu-
lating, somewhat concentric dark bands,
indicating parts where no double refraction
takes place.

PI. 39. fig. 10 gives but a very imperfect
idea of the appearances presented by these
crystals when viewed by polarized light.

C^EOM A 'CEI. See UREDINEI and U s-

TILAGrlNEI.

CALA'NUS, Leach, = TEMORA.

CALCARI'NA, D'Orb.— One of the Ro-
taline Foraminifera ; asymmetrically heli-
coid, with three or more whorls or cham-
bers ; coated with exogenous shell-growth,
as granules, spines, and stick-like processes.
Shell thick, with the vascular and supple-

mentary skeleton. Common in the Chalk
of Maastricht, and in several Tertiary strata ;
and living abundantly in the Mediterranean
and other warm seas.

C. Spengleri (PL 24. fig. 27).

BIBL. Reuss, Sitz. Ak. Wiss. Wien, xliv.
315, 1861; Carpenter, Foram. 1862, 216,
&c.

CALCIUM, CHLORIDE OF. — This salt
may be prepared by adding excess of pre-
pared chalk to dilute muriatic acid, boiling
and filtering the solution, and then evapo-
rating it to dryness. The crystals belong
to the rhombohedric system, and are de-
liquescent.

An aqueous solution of chloride of cal-
cium is of great service in microscopic re-
searches, as objects which have been im-
mersed in or moistened with it do not be-
come dry at ordinary temperatures. Hence,
if a drop of the solution be added to an ob-
ject covered with thin glass, and excluded
from dust, it may be preserved without the
use of a cement to enclose it in a cell (see
PRESERVATION). Its use in determining
the presence of cell-membranes has been
already alluded to (INTRODUCTION, p. xli,
§ 4). When employed for this purpose, its
action must always be controlled by the
action of water, crushing, &c.

The strength of the solution may be
about one part of salt to two of water, or a
saturated solution may be used ; it should
be kept in one of the test-bottles (!NTROD.
p. xxvii), with a lump of camphor floating
on its surface.

It frequently happens that the solution
in which objects have been immersed (on a
slide) exhibits crystals. These usually con-
sist of either the chloride itself, the sulphate
or the phosphate of lime, the two latter
formed from the alkaline salts derived from
the object.

CALCULI. See CONCRETIONS.

CALEP'TERYX, Linn.— A genus of
Neuropterous Insects, belonging to the fa-
mily LlBELLULID^E.

CALIA, Werneck. — A doubtful genus
of Infusoria.

Char. Monads included in jelly (Pando-
rince) fixed to aquatic plants, not swimming
free. Two species.

BIBL. Werneck, Ber. de Berl. Ak. 1841,
377.

C ALI'CIUM, Ach.— A genus of Lichena-
ceous Lichens, tribe Caliciei.

Char. Thallus granular, powdery, squa-
mulose or evanscent. Apothecia black, sti-

CALIGONUS.

[ 128 ]

CALOTHRIX.

pitate or subsessile ; spores brown or black,
bperniatia short, oblong.

Eighteen British species. C. hyperellum :
on oak, lime, &c. Very common.

BIBL. Leighton, Lich.-Fl. 1879, 39 ; Tu-
lasne, Ann. d. Sc. N. 3 se'r. xvii. 209.

C ALIG'ONUS, Koch.— A genus of Aca-
rina, fam. Trombidina. Has the legs 7-join-
ted, and a line between cephalothorax and
abdomen.

C. niger. Not described by Koch, but
figured ; very minute.

BIBL. Koch, Uebers. j Murray, EC, Ent.
124.

CA'LIGUS, Miiller.— A genus of Crusta-
cea, of the order Siphonostoma, and family
Caliginea (CaligicUe).

Char. Head in the form of a large buck-
ler, having anteriorly large frontal plates,
which are furnished with a small suctorial
disk or lunule on the under surface of each
lateral portion ; antennae small, flat and
two-jointed. Thorax with only two distinct
articulations, thoracic segments uncovered ;
second pair of jaw-feet two-jointed and
not in the form of a suctorial disk. Legs,
four pairs with long plumose hairs, fourth
pair slender, of only one branch and serving
for walking.

Four species. Found upon the brill, cod,
mackerel, plaice, trout, &c. j length 1-5
to 1".

BIBL. Baird, Brit. Entom. pp. 256, 269.

CALLIDT'NA, Ehr.— A genus of Rota-
toria, of the family Philodinaea.

Char. Eye-spots absent ; a proboscis and
a foot with horn-like processes.

The rotatory organ is double, but not
furnished with a stalk ; proboscis also cili-
ated ; foot elongate, forked, and with four
accessory horn-like processes, hence with
six points altogether ; teeth small and nu-
merous (two only in each jaw in one species,
Gosse). Fresh water.

C. elegans, Ehr. (PI. 43. fig. 10). Crys-
talline ; length 1-70". (PI. 43. fig. 1 1, j aws.)

C. rediviva, Ehr. Granular or fleshy, ova
red ; length 1-70".

C. bidens, Gosse. Teeth two in each j aw ;
length 1-45".

C. constricta, Duj. Rotatory organ con-
stricted ; length 1-50".

C. parasttica, Gig. On Gammarus and
Asellus.

BIBL. Ehrenb. Inf. p. 482; Dujardin, Inf.
p. 655 ; Pritchard, Inf. p. 701 ; Gosse, Ann.
N. H. 1851, viii. p. 202 j Giglioli. Qu. Mic.
J. 1863, p. 237.

CALLITHAM'NION, Lyngb.— A iromi*
of Ceramiaceoe(Florideous Algae) ^containing
a large number of species, some common,
many rare. In the smaller species the struc-
ture is very simple, the branched feathery
fronds being composed of single rows of tu-
bular cells; in the larger species the stem
and larger branches are strengthened by
external filaments, which grow over the
original axis, apparently originating at the
base of the upper branches and growing
down (somewhat as in Batrachospermum).
Antheridia have been observed in C. Uorrcri
and C. corymbosum, collected in tufts on
the ultimate branches. The favellce are
naked, and the tetraspores are tetrahedrally
arranged.

BIBL. Harvey, Mar. Alga, pi. 23 A ;
Phyc. Sr. pis. 129, 272, 230, &c. ; Thuret,
Ann. d. Sc. N. 3 se'r. xvi. p. 16, pi. 4 ; Na-
geli, Algen-Systeme, 198, pi. 6.

C I ALLODI'C'TYON, Carter.— A genus of
Rhizopoda (Flagellate Infusoria, Kent).

Char. Naked, free, ovate or variable,
highly vacuolar ; flagella three, food admit-
ted by the surface.

C. triciliatum. Length -^Q". Fresh
water, Bombay.

BIBL. Carter, Ann. N. H. 1865 : Kent.
Inf. 307.

'CALO'CERA.— A genus of Clavariei
(Hyrnenomycetous Fungi) differing from
Clavaria in the subcartilaginous texture and
viscid hymenium ; the structure moreover
approaches that of Tremellini. C. viscosa,
which occurs on decayed pine-stumps, is one
of our most beautiful Fungi. Three or four
more species occur in this country.

BIBL. Berk. Outl. p. 284.

CALODIS'CUS, Rabenhorst, = Campylo-
discus.

CA'LOTHRIX, Ag.— A genus of Oscil-
latorieae (Confer void Algae), growing in
tufts, the filaments forming a branched
frond by lying in apposition and being con-
creted by their sheaths here and there.
C. mirabilis, Ag. (PI. 8. fig. 22), is a rare
freshwater species in England, found on
mosses in small streams, seruginous green,
growing blackish. Diameter of the fila-
ments about 1-1200 to 1-1800". Accord-
ing to Hassall, C. atroviridis, Harv., is not
distinct.

Other species.

Fig. 95 illustrates the close annulations on
the filaments of this genus ; the nature of
which will be treated more particularly
under the head of OSCILLATORIACE^.

CALYCELLA.

[ 129 ]

CAMBIUM.

BIBL. Hassall,^«,243,pl.69.1; Fig. 95.
Kiitzing1, Tab. Phyc. cent. ii. pi. 29.
ii. ; Dillwyn, Br. Conferva (C. mi-
rabih'g), pL 9(3; Rabenhorst, Sp. Alg.
ii. 270 ; Bornet & Thuret, Notes
Algol

CAL YCEL'LA, Hincks.-A ge-
nus of marine Zoophytes, of the
order Hydroida, and "family La-
foeidae.

Char. Stem creeping, simple; or
erect, compound and branched ;
cells tubular, with an operculum
formed of convergent segments or
a plaited membrane ; polypes cy-
lindrical, with a conical proboscis.

C. syringa = Campanularia syr.
Very common on sea-weeds, &c.

sJ /• ,• • , Calothru

C. fastl</iata. Tomasi-

BlBL. Hincks,J9r/£ Zoopk.-p.2Q5. niana.

CALYMPERACE.E.-A tribe ^^
ol Fottioid Mosses, containing one of a
British genus : Mlame£S

Encalypta. Calyptra long, cylin- steams
drically bell-shaped, narrow above
on account of the clavellate operculum,
surpassing the capsule, firm, entire, torn or

Fig. 96.

Fig. 98.

Fig. 96. Encalypta vulgaris. Peristome.

Fig. 97. E. ciliata. Calyptra.

Fig. 93. E. streptocarpa. Fragment of peristorae.

ciliated below (fig. 97). Peristome absent,

simple (fig. 90), or double (fig. 98). Ex-
ternal : sixteen lanceolate or long-subulate,
ciliiform teeth, mostly with a longitudinal
line, reddish, rugulose. Internal : a delicate
membrane adherent to the teeth, produced
into cilia opposite or alternating with the
teeth.

CALYPOGE'IA, Raddi.— A genus of
Jungermannieae (Hepaticae), founded on
Jungermannia Trichomanis, Dicks. The
leaves have a peculiar glaucous hue ; the
sporange is spirally twisted. Gemmae are
produced at the extremities of leafless pro-
longations of the stem.

BIBL. Hooker, Brit. Jungerman. pi. 79;
Eng. Botany, 1728.

C ALYPTOS 'TOM A, Cambridge.— A ge-
nus of Acarina, fam. Trombidina.

C. Hardii. Eeddish -yellow, punctate;
eyes 6, in 3 pairs, forming a triangle.

Among moss ; Cheviot Hills.

BIBL. Cambridge, Ann. N. Hist. 1875,
xvi. 384 (fig.); Murray, EC. Entom. 140.

CAM'BIUM.— The name applied to the
young cellular layers from which the woody
structures of plants are developed. When
sections are made near the growing points of
any stems, as in. terminal or axillary buds,
we find a quantity of extremely delicate,
slender, elongated cells, distinguished from
the generally rounded cells of the paren-
chyma, and forming rudimentary cords in
the situation of the future woody and vas-
cular bundles. In the Dicotyledons, they
stand in a circle, so as to separate the
pith from the young bark : the ring may
be seen in cross sections a little below the
growing-point. At the very apex of the
stem all the tissues merge into the delicate
universal generative tissue or meristem. In
the apex of Monocotyledonous stems, and
also those of Ferns and the higher Flower-
less plants, the cambium is found in delicate
cords imbedded in the nascent general pa-
renchyma, indicating, even in this early
condition, the position and arrangement of
the isolated fibrous and vascular bundles.
Sections of the outer region of the stem of
Dicotyledons demonstrate the existence of
a layer of cambium at the outer surface of
the youngest wood, which indeed passes
gradually into the cambium (figs. 792, 808).
This cambium is the tissue from which the
succeeding layers of wood are generated ;
and its position on the outside of the fibro-
vascular bundles gives these their indefinite
power of development. The cambium of
the Monocotyledonous bundles becomes in-

CAMBRIC.

[ 130 ]

CAMPTOCERCUS.

closed between the wood and vessels of in-
dividual bundles, so that their growth is
limited. The cambium of the outside of
the wood of Dicotyledons forms new layers
of liber, in most cases, on the inside of the
old ones, pari passu with the development
of the layers of wood. Cambium, which
is in great part only an early and trans-
itional form of cellular tissue, afterwards
to become developed into wood, is com-
posed of delicate cellulose cells enclosing
a primordial utricle, nucleus, and abun-
dance of nitrogenous protoplasm, but usually
without chlorophyll. The cells multiply
b}r transverse division in the elongation of
the stem, and by perpendicular division
( tangential and radial) as the stem expands
in diameter. This process is effected by
the constriction of the primordial utricle
and gradual development of a septum, as
in ordinary vegetative cell-development.
The cambium of most Dicotyledons is gra-
dually matured into wood from within
outwards ; but in the Monocotyledons and
Flowerless Cormophytes it often remains in
great part in a delicate and soft condition,
forming the vasa propria of Mohl. Owing
to the delicacy of its structure, cambium
was formerly imagined to be a thick muci-
laginous fluid poured out in the growing re-
gions of plants (as between the wood and
liber of Dicotyledonous stems in spring) ;
which by degrees becomes organized and
converted into cellular tissue, by the inde-
pendent origin and subsequent coalescence
of a number of cells generated in this fluid.
This erroneous view was strongly supported
by Mirbel and others.

BIBL. Treviranus, Phys. d. Gewachse, i.
159; Mirbel, Ann. d. So. N. 2 ser. xi. 321,
xix. 197; Payen, C'ompt. Rend. 1839; Schlei-
den, Botanik ; Henfrey-Masters, Botany ;
Nageli, Zeitsch. f. wiss. Bot. iii. 64, & Mikr.
576; M.oh},Veaetab.ZeUe(Transl.y, Schacht,
Pflanzenzelle ; Sachs, Bot. 83.

CAMBRIC. — This name was formerly ap-
plied strictly to the finest kind of linen cloth.
It is used now in a loose sense in trade.
French cambric, however, ought to be linen.
Scotch and English cambrics are commonly
made of cotton, while Indian cambric is
made of the grass-cloth fibre. The fibres
may be distinguished under the microscope,
and the value of the fabric thus ascertained.
See FIBROUS SUBSTANCES and COTTON.

CAMERA LUCIDA. INTRODUCTION,
p. xxii.

CAMPANULA'RIA, Lamk.— A genus

of Hydroid Zoophytes; family Campanu-
lariidee.

Distinguished by the creeping or erect
polypidom, the filiform continuous main
tube, giving off its stalked and campanulate
cells irregularly or in whorls, the usually
long, ringed stalks, and the scattered, ses-
sile vesicles.

Hincks defines the genus thus : — Stems
simple or branched ; cells bell-shaped and
hyaline, without operculum ; polypes with a
large cup-shaped proboscis; germ-cells borne
on the stems or the creeping stolon, with
fixed spore-sacs. 13 species; 3 doubtful.

C. volubilis (PI. 41. fig. 4). Stem a
single tube, creeping, filiform ; cells on long,
slender ringed stalks, campanulate, with a
serrated margin; vesicles ovate, wrinkled
concentrically. Parasitic on sea- weeds &c. ;
frequent. It forms an elegant microscopic
object.

C. dumosa. Stem compound, erect or
climbing, irregularly branched; cells long,
tubular, patent, almost sessile, orifice entire.
In deep water.

BIBL. Johnston, Brit. Zooph. 107; Gosse,
Mar. Zool. i. 24 ; Hincks, Brit. Zooph.
160.

CAMPANULAR'IID^, Johnston.— A
family of marine Hydroid Zoophytes.

Char. Those of Sertulariidse,' but cells
stalked.

Genera: Campannlaria, Laomedia.

Hincks revises the family thus: Cells
terminal, stalked, campanulate ; polypes
with a large trumpet-shaped proboscis.
And admits the genera Clytia, Obelia, Cam-
panularia, Lovenella, Thaumantias, and Go-
nothyrcea.

BIBL. Johnston, Brit. Zooph. ; Gosse,
Mar. Zool. i. ; Hincks, Br. Zooph. p. 137.

CAMPANULI'NA, Van Beneden.— A
genus of marine Hydroid Zoophytes ; family
Campanulinidae.

Char. Stem simple or branched, rooted ;
cells pointed above; polypes cylindrical,
with webbed tentacles ; reproduction by
free medusa-buds, single in each capsule.
3 species.

BIBL. Hincks, Brit. Zooph. p. 186.

CAMPANULI'NID^E.— A family of
Polypi, order Hydroida.

Char. Cells ovato-conic, stalked; polvpes
long, cylindrical, with a small conical pro-
boscis.

Genera : Campanulina, Zygodactyla, Oper-
cularella.

CAMPTOCER'CUS, Baird (Lynceus

CAMPTOSURUS.

[ 131 ]

CANDONA.

Miill. pt.). A genus of Entomostraca, order
Cladocera, family Lynceidae.

Char. Carapace ovoid ; beak blunt, di-
rected forwards or slightly downwards j ab-
domen long, slender, tail-like, extremely
flexible, and serrated. 1 species :

C. macrourm (PL 20. %. 4). Carapace
striated longitudinally, slightly sinuated and
ciliated on the anterior margin j beak rather
blunt; aquatic.

BIBL. Baird, Brit. JSntom. p. 128.

CAMPTOSU'RUS, Presl, = Scolopen-
drium, pt.

CAMPTOTHE'CIUM,Br. & Sch. = Hyp-
num in part.

CAMPTOUM, Link.— A genus of De-
matiei (Hyphomycetous Fungi), allied to
Arthrinium. C. curvatum, Lk. (Arthrinium
curvtitum, Kze.) grows in tufts of very slen-
der filaments, bearing very minute, curved
spores, upon Scirpu* si/lvaticus.

BIBL. Berk, and Br. Ann. N. H. 2 ser.
viii. 100 ; Fries, Syst. Myc. iii. 377 ; Corda,
Ic. Fung. iii. pi. 1. fig. 17.

CAMPYLODIS'CUS, Ehr.— A genus of
Diatomaceas.

Char. Frustules single, free, disk-shaped ;
disk curved or twisted (saddle-shaped) ; fur-
nished with mostly radiate markings, which
are frequently interrupted. Aquatic and
marine.

The markings are costfe or canaliculi,
forming minute canals between the internal
cell-membrane and the surrounding fluid
(Smith).

Smith describes 9 species (British) ; Ra-
benhorst describes 28 European species, and
enumerates 27 foreign and fossil species.

C. costatus, Smith (PI. 1 6. fig. 16). Valves
circular j radii 30-40, extending about half-
way to the centre, which is minutely
punctate ; diameter 1-270" ; aquatic.

C. spiralis, Smith. Outline of front view
resembling a figure of 8 ; valves elliptical j
radii about 60, nearly parallel and trans-
verse ; length 1-160" ; aquatic.

C. dypeus, Ehr. (PI. 25. fig. 18). Valves
suborbicular, exhibiting a circular and a me-
dian transverse hyaline line ; radii broad,
interrupted in the middle, which is punctate ;
length 1-200" ; aquatic and fossil.

BIBL. Smith, Br. Diat. ; Kiitzing, Bacill.
and Sp. Alq. ; Rabenhorst, Fl. Alg. i. 45 ;
Grun, men. Verh. 1862 j Schmidt, Atlas
Diatom.

CAMPYLONE'IS, Grun.— A genus of
Diatomacese, family Entopyleae.

Char. Frustules scutelliform, adnate,

transversely arcuate ; valves heterogeneous
— the inferior costate, the superior cribroso-
punctate ; nodules absent.

C. Argus. Atlantic.

BIBL. Grun, Wien. Verhandl 1862, 429.

CAM'PYLOPUS, Brid. (Musci) = Di-

CRANUM.

BIBL. Wilson, Bryol. Brit. p. 87.

CAM'PYLOPUS, Cl. and Lachm— A ge-
nus of marine Infusoria, family Oxytrichiua.

C. paradoxus (PI. 51. fig. 29). With six
posterior setse, and eight posterior feet, six
on the right and two on the left side. Re-
markable for its bounding leaps, which
make it very difficult of observation.

BIBL. Claparede and Lachmann, Infus.
p. 184.

CAMPYLOSTE'LIUM, Br. and Sch.—
A genus of Leptotrichaceous Mosses, inclu-
ding some Dicrana and Grimmice of older
authors.

BIBL. Wilson, Bryol. Brit. p. 51.

CAMPYLOS'T YLUS, Shadb.— A genus
of Diatomaceae : = Synedra, sp.

BIBL. Greville, Qu. Mic. J. 1862, 232.

CANADA BALSAM. See BALSAM.

CANALICULI. See BONE.

CANCER. See TUMOURS.

CANCROID. See TUMOURS, Cancroid.

CANDA, Lamx. (Cellularia part, John-
ston).— A genus of Infundibulate Polyzoa
(Bryozoa), of the suborder Cyclostomata,
and family Cellulariidae.

Distinguished by the jointed, branched,
erect polypidom, the flat, linear branches
with the cells on one plane, and the cells
having a vibraculum in a notch on the outer
side but no avicularium at the upper angle.

Placed with Scrupocellaria by Hincks.

C. reptans (Cellularia rept., Johnston)
(PI. 41. figs. 5, 5 c, and 5 d). Orifice oval,
with 3 or 4 marginal spines, and a stalked
operculum with a lobed lamina. Common.

BIBL. Johnston, Brit. Zooph ; Busk (Brit.
Mm.} Polyzoa, 26 ; Hincks, Polyzoa, 43.

CANDA'CE, Dana. — A genus of Ento-
mostraca (Copepoda).

G. pectinata. Dredged at Scilly.

BIBL. Brady, Copepoda (Ray Soc.), i. 48.

CANDEI'NA, D'Orb.— A modification
of the Globigerine type of Foraminifera
(according to Brady), built up with a
three-sided alternation, and having a row of
pseudopodial pores along the base of its last
chamber.

BIBL. D'Orbigny, For. Foss. Vien. 193 ;
Brady, Qu. Mic. Jn. 1879, xix. 78.

CANDO'NA,Baird(a/pr^inpart,Miill.).

CANNA.

[ 132 ]

CAPILLARIES.

— A genus of Ostracoda (Entomostraca),
family Cypridae.

Char. Two pairs of antennae; superior
long, with numerous joints and a pencil of
long filaments ; inferior stout and pediform,
without a tiift of long hairs or filaments (see
CYPRIS) ; eye single ; motion creeping only.
Five British species ; freshw.

C. albicans, Br. ; lactea, Bd.; compressa,
Koch; Candida, Mull.

BIBL. Baird, Entom. 159 ; Norman, Ann.
N. H. 1862, ix. 46; Brady, Linn. Tr. 1868,
xxvi. 381.

CANNA. — A genus of Monocotyledonous
plants belonging to the same natural family
as the arrow-root (Marantacese), and valu-
able from the same cause. Tous-les-mois is
a starch derived from the tubers of a Canna,
supposed to be C. edulis, Ker. The grains
of genuine Tous-les-mois have distinctive
microscopic characters, as shown in PI. 46.
fig. 25.

CANTHAREL'LUS.— A genus of Aga-
ricini (Hymenomycetous Fungi), differing
from Aqaricus in the vein-like gills.

CAN'THOCAMPTUS, Baird (Cydcps,

pt., Mull.).— A genus of Entomostraca, of
the order Copepoda, and family Cyclopidae.

Char. Jaw-feet small, simple; inferior
antennae simple ; ovary single.

Four species : one aquatic, three marine.

C. minutus (PI. 20. fig. 6). Thorax and
abdomen not distinctly separate, consisting
of ten segments, successively diminishing
in size, the last terminating in two short
lobes, from which issue two long filaments,
slightly serrate on their edges; antennae
short, seven-jointed in the male, nine- in
the female ; inferior antennae simple, two-
jointed, the first joint with a small lateral
joint, terminated by four setae ; feet five
pairs.

Common in ditches; colour reddish,
length about 1-15". (PI. 20. fig. 6 : a, in-
ferior antenna; b, first pair of jaw-feet;
c, second pair.)

C. cryptorum, Brady. In a coal-mine.

BIBL. Baird, Brit. Entom.', Brady, Qu.
M. Jn. 1869, p. 23.

CAOUTCHOUC. — A gum-resinous sub-
stance contained in the milky juices of many
plants, but most abundantly in those of the
families Euphorbiaceae, Urticaceae and Apo-
cynaceae, whence the India-rubber of com-
mence is obtained. The caoutchouc appears
in the form of minute globules suspended in
a watery fluid containing a gummy sub-
stance; so that the milky juice may be

regarded as a kind of emulsion. See
LATEX.

CAPILLARIES.— The minute interme-
diate vessels which the blood traverses in
passing from the arteries to the veins.

The capillaries appear to consist of a deli-
cate, transparent, tolerably resisting and
elastic membrane, and a number of oval or
rounded longitudinal nuclei ; but when
treated with very dilute solution of nitrate
of silver, the dark dyed outlines of the epi-
thelial cells, to which the nuclei belong, are
brought to light (PI. 51. fig. 31). The dia-
meter of the human capillaries varies from
1-5000 to 1-1000", the most common being
perhaps 1-3000". The size of the capillaries
in the Vertebrata generally, bears a relation
to the size of the coloured corpuscles of the

Fig. 99.

Magnified 300 diameters.

One of the smallest vessels from the arterial side. 1,
smallest artery ; 2, transition vessel ; 3, large capillaries ;
4, small capillary, a, structureless membrane with few
nuclei, representing the adventitious coat ; b, nuclei of
the muscular fibre-cells; c, nucleus inside the small
artery ; d, nuclei of the capillaries and intermediate
vessel. From the human brain.

blood ; and thus they are largest in Birds,
Fishes, and Reptiles. The larger capillaries

CAPNODIUM.

[ 133 ]

CARBASEA.

have thicker walls and more numerous cells
than the smaller ones.

The capillaries branch and anastomose
freely, giving rise to the beautiful networks
so well known as favourite microscopic
objects when injected.

The most important pathological changes
which the capillaries undergo are those of
the FATTY and AMYLOID DEGENERATION.
The general arrangement of the capillaries
is best seen in injected preparations (INJEC-
TION;. Their structure 'may be examined in
pieces of the pia mater, of the retina, or the
mesentery of an animal : a minute portion
of washed lung will also answer the purpose
well. These should be dissected with the
mounted needles. The relation of the ca-
pillaries to the surrounding minute struc-
tures may be shown in portions of tissue
which have been imperfectly injected, or
injected with a liquid containing a small
quantity only of opaque colouring-matter ;
in these the capillaries may be recognized
by their containing the scattered granules
of the colouring-matter. Between the cells
are certain spaces (stomata), best seen in
silvered preparations. In the spleen-pulp,
and in the tissues of many of the lower
animals, the finest currents of blood pass
through lacunae or wall-less channels.

The capillaries are developed from
branched connective corpuscles. Non->
medullated nerves have been traced into
the walls of the capillaries.

Acetic acid is frequently of use in rendering
the tissues transparent, and bringing the
nuclei to light. The finer capillaries are
made more distinct by dyeing with carmine
or logwood.

BIBL. Kolliker, Mikr. An.~B&. ii. ; Henle,
Ally. Anat. ; Frey, Histologie (full Biblio-
graphy) ; Schmidt, Mn. Mic. Jn. xiii.
1 (figs.) ; Eberth, StricJcer's Handbuch ;
Chrzonszczewsky, Virchoiv's Archiv, xxxv.
169 ; Cornil & Ranvier, Hist. path. ; Rind-
fleisch, Hist. ; and the BIBL. of TISSUES.

CAPNODIUM, Montagne.— A genus of
Perisporiacei (Ascomycetous Fungi) grow-
ing as a kind of mildew on leaves and shoots,
forming a blackish flocculent coat composed
of short, branched, beaded or moniliform
filaments, densely interwoven. The peri-
thecia arise vertically from this, and are
either simple or branched, at first simple
sacs, but probably afterwards thickened by a
layer of cells ; a number of threads ultimately
grow up from the mycelium, partiallycover
the central sac ; and, closely crowded, some

of their tips project beyond it, forming a
fringe; the cells of this fringe readily become
detached and appear to reproduce as conidia.
The central sac contains largish delicate asci,
probably often absorbed at an early period,
so as to set the spores free in the cavity.

Particular joints of the filaments some-
times become pycmdia, producing free spores
in their interior, without asci.

Several species seem to occur in Britain ;
and amongst them C. elongatum, Berk. &
Desm. On pear-leaves.

C. (Fumago) quercinum, Pers., grows on
oak-leaves.

C. (Fumago) Footii, Berk. & Desm., on
evergreens, on the birch-tree, and on Mer-
curialis perennis.

BIBL. Berkeley, Crypt. Bot. p. 275 ; Berk.
& Broome, Ann. N. H. 2nd ser. xiii. p. 468 ;
Berk. & Desmazieres, J. Hort. Soc. iv. 243 ;
Montagne, Ann. N. H. 2nd ser. iii. p. 520.

CAPSOSI'RA, K.— A genus of Rivu-
larieae.

Char. Filaments erect, narrow, crowded,
parallel, moniliform, sheathed j cells thick-
walled.

C. JBrebissonii (PI. 53. fig. 11.). Greenish
black. On stones, in streams (France).

BIBL. Kiitzing, Sp. Alg. 344; Raben-
horst, Fl. Alg. ii. 223.

CARAPACE, or Lome A. — A term some-
what indefinitely applied to the whole or a
part of the shell or outer coat of certain
animals — as those belonging to the classes
Crustacea, Rotatoria, Infusoria, &c.

In regard to the Rotatoria and Infusoria, it
has been divided into : — the testa or testula,
an envelope resembling that of the tortoise,
within which the body of the animal is en-
closed, the head and the tail being free — as
in the genera Brackionus, Monura, Colurus,
&c. ; the scutellum, a round or oval envelope,
covering only the back of the animal, in the
manner of a buckler; and the urceolus, a
membranous or firm envelope, sometimes
gelatinous, in the form of a bell or cylinder,
open at one end and closed at the other, and
within which the animal can- completely
retract itself — as in DIFFLUGIA &c.

Ehrenberg extended the use of this term
also to the external envelope of Volvox,
Gonium, and the Diatomacese. As these
have been removed to the vegetable kingdom,
it is not now applied to them.

CARBA'SEA, Gray.— A genus of Infun-
dibulate Polyzoa, of the suborder Cheilo-
stomata, and* family Flustridae (Flustra, pt.,
Hincks).

CARBOLIC ACID.

134 ]

CARPOMITRA,

Distinguished by the expanded, leafy,
flexible, erect j)olypidoms ; and the cells
being arranged in many rows, on one side
only.

C. papyrea (Flustra carbasea, Johnst.)
(PI. 41. tigs. 19, 20). Cells oblong, narrowed
and truncate below, convex, unarmed. Deep
waters.

BIBL. Johnston, Br. Zooph. 345 ; Busk,
Mar. Polyzoa, 50 ; Hincks, Polyz. 123.

CARBOLIC ACID or PHENOLE.— This
substance is largely used as a germicide and
antiseptic, and is Very valuable in the pre-
servation of animal and vegetable structures.
The pure crystallized acid should be pro-
cured. See PKESERVATION.

CARBONATE OF LIME. See LIME,
Carbonate of.

CARBO'NIA, Jones.— A genus of small
Cypridiform JEntomostraca, found in the
Carboniferous strata, and distinguished
chiefly by their peculiar muscle-spot.

BIBL. T. R. Jones, Geol. Mag. iii. 218,
pi. 9, f. 4-10 ; Jones & Kirby, Ann. N. H.
1879, iv. 28.

CARBONIC ACID.— The presence of
this gaseous acid is usually determined by
the addition of another acid, as acetic or
muriatic, to the object under the microscope;
and if colourless and inodorous bubbles
escape, it is concluded, and in most cases
correctly, that carbonic acid is present.

It must be borne in mind that if the object
be immersed in liquid, the gas may arise
either from this or the object ; for it is well
known that the escape of a gas from a liquid
charged with it is greatly facilitated by the
presence of a solid and especially a pointed
body, and that the gas escapes from the
liquid at its surface or point; thus the
false appearance is produced of the gas being
liberated from the body. Hence the import-
ance of washing the object before the addition
of the acid.

When crystalline bodies of different forms
are present, these must be separated before
the addition of the acid; otherwise the bubbles
liberated from those of one kind, by escaping
at the surface of the others, may give rise to
the false conclusion that they were derived
from the latter.

Recollection of the fact that carbonic acid
is readily absorbed by solution of potash,
would allow of the distinction of bubbles
of this acid from those of air.

CARCHE'SIUM, Ehr.— A genus of
Infusoria, belonging to the family Vorti-
cellina.

Char. Pedicle branched, spirally flexible ;
bodies of the animals all alike ( = branched
Vorticellce}.

C.polypinum (PI. 30. figs. 20, 21). Cam-
panulate, expanded in front ; cuticle smooth ;
nucleus recurved in a longitudinal plane ;
peduncle not jointed; length of bodies
1-580-1-430"; freshw.

C. spectabik. Thimble-shaped, not ex-
panded ; cuticle finely striated ; nucleus re-
curved in a longitudinal plane, with several
sinuosities; peduncle not jointed ; freshw.,
foetid.

C. Epistylis. Body very narrow, smooth ;
nucleus curved in a transverse plane ; pe-
duncle distinctly jointed; freshw., in insect-
larvae.

BIBL. Ehrenb. Inf. and Ber. d. Berl. Ak.
1840, 199 ; Dujardin, Inf. 551 ; Stein, Infus.
48, &c. ; Clap, and Lachm. Inf. 97; Kent,
Infusoria, 690.

CA'RIS, Latreille. — A doubtful genus of
Acarina.

C. vespertilionis is found upon the bat
( Vespertilio pipistrellus), supposed to be the
larva of Dermanyssm, or Argas.

BIBL. Latreille, Gen. Crustac. fyc. i. 161 ;
Audouin, Ann. d. Sc. N. Zool. xxv. 412 ;
Walckenaer, Apteres (Gervais), 227.

CARMINE.— This beautiful pigment is
sometimes used to feed Infusoria and fill
their sacculi or gastric spaces (INFUSORIA).

It is also used as a colouring-matter for
injections and for dyeing or staining tissues
(see STAINING).

CAR'PAIS. See GAMASUS.

CARPENTE'RIA, Gray.— A genus of
Foraminifera allied to Globigerina, but
ceasing at an early age to grow spirally, and
then forming expanded tent-like chambers
which enclose the first-formed cells ; at-
tached by the base to shells or corals, and
with a crater-like common aperture at the
apex. Siliceous spicules occur in the cells.

C. balaniformis. (PI. 51. fig. 28.)

BIBL. Carpenter, Introd. For am. 186.

CARPOGLY'PHUS, Robin, = Acarus
sp. (p. 5).

CAR'POGON,the name applied by Sachs
to the fruit or sporocarp of his Class Car-
posporeas. See VEGETABLE KINGDOM.

CARPOMI'TRA, Kiitz.— A genus of
Sporochnacese (Fucoid Algae) containing
one rare British species, C. Cabrera, Clem.,
remarkable for the peculiar mitre-shaped
conceptacle containing the spores.

BIBL. Harvey, Marine Alg. pi. 5 B,
Phyc. Brit. pi. 14.

CARTILAGE.

[ 135 ]

CARTILAGE.

CARTILAGE.— Cartilage consists of a
firm, but elastic, bluish, milky or yellowish
substance, which morphologically forms
either a simple parenchyma composed of
cells, or a structure consisting of cells
immersed in an intermediate basis.

The cells of cartilage are usually round,
oval, elongated or angular, frequently flat-
tened and sometimes spindle-shaped. In
some cartilage they appear stellate, or ex-
hibit distinct radiating processes, as in
that of the cuttle-fish, the sharks and rays,
and enchondromatous growths.

In the ossifying pseudo-cartilage of true
bone, real stellate cells are however met
with. See BONE.

Pig. 100.

Magnified 350 diameters.

Primary (parent-) cells with one and two nuclei, or
two and four secondary cells and intervening basis.
From the cranial cartilage of a full-grown tadpole.

The cell-walls are generally thick, and
frequently composed of several layers or
capsules. The contents consist of a clear
liquid and a nucleus ; sometimes the cell
and sometimes both the cell and the
nucleus contain one or more globules of
oil. The cells also frequently constitute
parent-cells, i. e. cells containing other or
secondary cells within them, these con-
taining also nuclei or tertiary cells.

The secondary and tertiary cells some-
times exhibit well the internal layers.

It is undecided whether these capsular
layers are hardened products of secretion of
th*e cells, or whether they represent the
changed peripheral portions of the cell-
bodies themselves. The latter seems most
probable.

The intervening basis is either homoge-
neous, finely granular, or fibrous ; sometimes
the fibres are distinct and can be isolated.

The simplest form of cartilage, viz. that
composed of cells only, is met with in the
chorda dorsalis or notochord of embryos, in
the adult skeleton of many fishes, the ten-
tacles of the Acalephae, and in the cartilage
of the ear of many mammals. The proto-
plasm in these cells often exhibits radiating
striae in which currents are visible. The
structure is beautifully seen in the chorda
dorsalis of a young tadpole or Triton, or in
the ear of the mouse (PL 49. fig. 38). In

Fig. 101.

*-•""

Magnified 350 diameters.

Cells from the gelatinous nucleus of the interverte-
bral ligaments. 1 a, large primary cell with a septum
formed by two secondary cells, and five tertiary cap-
sular cells or cells of the second generation with concen-
tric walls and shrunk nuclei c in the small cell-cavities.
2, primary cell a, with two secondary cells separated
by a delicate septum 6, with thickened walls, a small
cavity and a shrunk nucleus c.

the latter instance, each cell is filled with
a globule of oil, which must be separated by
digestion in ether before the cell -structure
can be properly examined ; but boiling on a
slide in solution of potash, or the addition
of sulphuric acid will liberate the globules
of fat from parts of a section. This variety
of cartilage exactly resembles in appearance
a section of vegetable cellular tissue.

The second variety of cartilage, in which
the basis is more abundant and homo-
geneous or finely granular, true or hyaline
cartilage as it is called (PI. 49. fig. 39), is
met with in the larger cartilages of the
respiratory organs, in the articular, costal,
ensiform and nasal cartilages. In this the
cell- walls are closely adherent to the inter-
cellular basis, so that they are rarely visible
without the use of reagents. The cells are
most numerous in the articular cartilages,
and are mostly smaller the further they are
from the bone. Their long axes are placed
perpendicularly to the axis of the bone,
except in a thin layer next the surface of
the joints, in which they are parallel to the
surface. Both the cells and the nucleus of
this cartilage exhibit a fibrous network.

CASEINE.

[ 136 ]

CATHARINEA.

The third variety of cartilage forms fibro-
or reticular cartilage (PL 49. fig. 40). In
this, the fibres consist either of white
fibrous tissue, forming white fibro-cartilage,
as in the intervertebral and interarticular
cartilages ; or of elastic tissue, forming
yellow or elastic fibro-cartilage, as in the
epiglottis, the ear, and the Eustachian tube.
It consists principally of fibres, single or in
bundles, sometimes running parallel, at
others interlacing; and between them lie
the cartilage corpuscles. Sometimes the
basis of hyaline cartilage becomes fibrous,
and true fibres may be found in it.

Bubnoff describes, in cartilage treated
with osmic acid, a complex network of
canals, passing in all directions through the
cartilage.

In regard to chemical composition, the
homogeneous basis usually consists of ehon-
drine. The cell- walls are composed of a
substance allied to elastic tissue ; they are
not dissolved by boiling in water, and are
acted upon with difficulty by acids and
alkalies. The liquid within the cells is
probably albuminous; it is coagulated by
water and dilute organic acids, and is readily
soluble in alkalies.

When sections of cartilage are subjected
to the action of Schultze's test, the cells
are coloured red, but not the basis.

By macerating hyaline cartilage in dilute
acids or warm water, the matrix often
exhibits concentric laminae.

Some staining agents are useful in
enabling the components of hyaline cartilage
to be distinguished. Thus, the fat-globules
are blackened by osmic acid ; chloride of
gold colours the cells violet ; and nitrate
of silver stains the matrix (Rutherford).

BIBL. Kolliker, Mik. An. Bd. i. ; Henle,
Allg. Anat. ; Redfern, Ed. Month. Journ.
1851-1854 ; Mulder (and Bonders), Phys.
Chemie] Frey, Histol. 184; Bubnoff, Ber.
d. Wien. Ak. Ivii. ; Klein, Hist., 48 ; Ge-
genbaur, Vergl. An. 27; Rollett, Strieker's
Gewebel. ; and the BIBL. of TISSUES.

CASEINE is the proteine constituent of
milk. It possesses no microscopic charac-
ters.

Some years since, a tumbler containing
porter, at the bottom of which was a small
quantity of a whitish sediment, was brought
to us for examination, suspicion being enter-
tained that the white deposit consisted of
some poisonous substance which had been
added by a woman with the view of poisoning
her husband, the two not being on good

terms. The deposit examined microscopi-
cally and microchemically was found to
consist of an amorphous substance, giving
the chemical reactions of a proteine com-
pound, with entangled globules of oil. This
rendered it probable that it consisted of the
caseine of milk, with globules of butter.
It was afterwards recollected that milk had
been put into a tumbler kept in the place
from which this had been taken ; and thus
the matter ended.

CASSAVA.— The coarser part of the
starch (tapioca being the finer) derived from
the tuberous root of the Jatropha Manihot,
L. (Janipha Manihot, Knth. ; Manihot uti-
lissima, Pohl), a Brazilian plant of the
family Euphorbiaceae. The starch-grains
are represented in PI. 46. fig. 14.

CASSEBEE'RA, Kaulf.— A genus of
Pteridea3 (Polypodiaceous Ferns), nearly re-
lated to Adtantum. 3 species : Brazil.

BIBL. Hooker, Syn. Fit. 142.

CASSIDULI'NA, D'Orb.— A group of
Foramimfera subordinate to Bulimina. The
chambers are alternate in unequal pairs, and
form a more or less discoidal, instead of
spiral, coil. The aperture is oblique, formed
by an inverted slit-like fold of the lower
part of the septal face, as in Bidimina.

Two British recent species, C. Icevigata
(PI. 23. fig. 45) and crassa, are common; and
a few others, with these, are found in all
seas, and in the middle and later Tertiaries.

BIBL. Williamson, Foram. 68, figs.
140-144 ; Carpenter, Foram. 197 ; Parker
and Jones, Phil. Tr. civ. 377.

CATASCO'PIUM, Brid.— A genus of
Bartramioidese (Acrocarpous Mosses).

BIBL. Wilson, Bryol. Brit. p. 285; Berke-
ley, Brit. Mus. p. 168.

C ATENEL'LA ,Grev.— Agenus of Cryp-
tonemiacese (Florideous Algae), represented
by one British species, C. Opuntia (PI. 4.
fig. 21), which is not uncommon on marine
rocks near highwater mark. It presents a
mass of creeping fibres, from which arise
densely matted fronds 1-2 to 1" high.
Colour dull dark purple. Thefavellidia are
contained in the lateral capsular bodies
(fig. 102) ; the tetraspores are imbedded in
the periphery of the loosely cellular axis
(fig. 103).

BIBL. Greville, Alcj. Brit. pi. 17; Harvev,
Br. Mar. Alq. pi. 20 B; Phyc. Brit. pi. 88 ;
Enql. Bot. (Rivularia Opuntia). pi. 1868

CATERPILLARS. See INSECTS.

CATHARI'NEA, Ehrh.— A genus of
Polytrichaceous Mosses, containing some of

CATTLE-PLAGUE.

[ 137 ]

CELL,

Fig. 102.

Fig. 103.

Catenella Opnntia.

Fig. 10?. Fragment of a frond, with lateral capsular
bodies containing the faveilidia. Magnified 10 dia-
meters.

Fig. 103. Transverse section of the axis, showing the
immersed tetraspores. Magnified 50 diameters.

the Polytricha of authors, having a naked
calyptra ; —Atriclium and Oligotrichum of
Wilson's Bryologia.

BIBL. Wilson, Bryol. Brit. pp. 202, 204.

CATTLE-PLAGUE or Rinderpest.—
This terrible disease requires a brief notice
on account of its microscopic relations.
Careful examination of the muscles of ani-
mals which had died of it showed the pre-
sence of "Entozoa." These were found
afterwards to be Psorospermice, and to exist
in healthy as well as in diseased animals ; so
that they had no connexion with the malady.
A most copious Bibliography of the para-
sites infesting cattle is given in Cobbold's
work, p. 352.

BIBL. Beale, Qu. Mic. Jn. 1866, p. 141
(figs.) ; Cobbold, Parasites, 1879, p. 280.

CAYENNE PEPPER.— This substance
consists of the ground seed-vessels of various
species of Capsicum ; it is often adulterated
both with substances increasing the bulk,
and with mineral colouring-matters. For
the detection of the former the microscope
is employed, first studying the characters
observed in the true un ground peppers.
Turmeric and rice-flour are named as falsify-
ing substances ; red earths, vermilion, and
red lead are detected by chemical analysis.

BIBL. That of Adulterations.

CECIDOMY'IA, Latr.— A genus of Dip-
tera, of the family Tipulidee.

C. tritici is the wheat-midge, which de-
posits its eggs in the flowers of corn. The

yellow larvae wound the ovary, and so cause
a form of blight.

C. destructor, the American wheat-midge,
or Hessian fly, is still more injurious to
crops.

These insects may be found among the
ears of corn in the evening during the mouth
of May or June.

BIBL. Kirby, Linn. Tr, iii., iv., v. ; West-
wood, Intr. p. 519 ; Sidney, Blights of the
Wheat, p. 109.

CE'CROPS, Leach.— A genus of Crusta-
cea, of the order Siphonostoma, and family
aligina.

C. Latreillii. Found on the sun-fish
(Orthagoriscus mold). Female, length 1",
male 1-3".

BIBL. Baird, Brit. Entomost. p. 289 j V.
d. Hoeven. Handb. d. Zoologie, i.

CEDAR.— The Cedar of Lebanon is the
Abies or Pinus Cedrus. The fragrant so-
called ( cedar,' of which pencils &c. are
made, is the wood of Juniperus virginiana.
See CONIFERS and WOOD.
CELL, ANIMAL. — The tissues and organs
of animals, like those of plants, are in great
part made up of or derived from cells ; but
the full-grown structures of animals are
strikingly distinguished in general from
those of vegetables by the departure from
or disguisal of the primitive cellular consti-
tution.

Under the head of CELL, VEGETABLE,
the cell is defined as a vesicle or sac con-
sisting of a membrane composed of cellu-
lose, containing within it a nitrogenous
structure, the vital part, called the proto-
plasm or primordial utricle. In animals, as
in the earlier stages of many plants, this
protoplasm may exist alone, either forming
the entire organism, or its parts only, with-
out a membranous envelope forming the
true cell or closed sac, as in Amoeba and
analogous organisms; but ordinarily the
animal cell, like the vegetable, is a true shut
sac, enclosing liquid or gelatinous protoplas-
mic contents, the membrane, however, being
here almost always composed of a nitroge-
nous compound, and only in a few cases of
cellulose or allied substances such as pre-
vail in the solid parts of plants.

The membrane of animal cells is ordinarily
transparent and colourless, mostly smooth,
and so thin as to exhibit only a single
boundary line ; more rarely the membrane
is tolerably firm, presenting a measurable
thickness, — while it is sometimes very thick,
and appears to consist of several layers.

CELL.

[ 138 ]

CELL.

Occasionally the membrane has a granular
appearance, arising from projections de-
pendent on granules lying on the inside.
No structure can be detected in the cell-
membrane itself.

The membranous cell generally contains
a liquid or semifluid protoplasm, the consis-
tence of which varies ; in this float, or are
suspended, molecules, granules, globules, or
other very minute cells. But modern ob-
servations indicate the existence of a net-
work of filaments, traversing the substance
of the protoplasm. In most cells, we also
find one or more of those bodies which are
termed nuclei) often attached to some part
of the cell-wall ; in these again, a network
of fibres is stated to occur. The nuclei con-
tain nucleoli. The cell-contents likewise in-
clude, in particular structures, products of
secretion — matters separated by the cells
from the circulating fluid, as in the cells of
the renal epithelium, &c., — also crystals,
pigment, &c.

The forms presented by animal cells are
not so varied, or generally so geometrical,
as those occurring in the cells of vegetables.

In regard to size, the largest are the yelk-
cells of ova, especially of Birds and Reptiles,
and of some animals consisting of a single
cell, as certain of those curious organisms
the Greyarina.

The nuclei are usually spherical or lenti-
cular, non-contractile, transparent, and co-
lourless or yellowish. They are sometimes
solid or homogeneous ; at others they are
vesicles, with a very delicate membrane.
They sometimes contain, exclusively of the
nucleolus, a transparent colourless or yel-
lowish liquid, in which water and acetic
acid produce a precipitate of granules re-
sembling those existing in the cell-contents ;
hence in the ordinary manner of examining
them they seldom present their natural
transparency. The nuclei seem to be se-
creted or formed by the protoplasm, and
are regulators of the vital phenomena.

The nucleoli are rounded, well defined,
very minute, sometimes immeasurable.

Chemically, the cell-membrane ordinarily
consists of a proteine compound; it is mostly
dissolved, or rendered so transparent as ^ to
become invisible, by acetic acid and solution
of potash ; thus differing in a striking man-
lier from that of vegetable cells. Cell-mem-
branes composed of cellulose occur in some
animals, as in the Tunicata &c. ; it is de-
tected here, as in plants, by the action of
iodine and sulphuric acid. The nucleoli

consist also of a proteine compound ; they
are soluble in potash,' but not in acetic acid.
The action or potash distinguishes them
from globules of fat. The carmine-am-
monia solution has a much more rapid and
powerful dyeing action upon the protoplasm
and the nuclei than upon the cell-walls.

It must be remarked that the appearances
interpreted to be nuclei and nucleoli are
frequently not respectively identical in
kind; the nuclei are sometimes homogene-
ous, at others true cells ; sometimes they
relate to the formation of the cell ; at others
they are young secondary cells, vacuoles,
&c. ; the same applies to the nucleoli. These
important points have not hitherto received
sufficient attention.

Cells, or rather their protoplasms, are en-
dowed with peculiar vital forces, by which
they are capable of free movement, absorp-
tion, and the elaboration of the absorbed
matter; of growth, reproduction, and of
secretion. The entire organism of the higher
and most of the lower animals consists, at
a certain period of life, of cells, but some-
times of protoplasm alone.

Formation of Cells. — Cells are formed in
two ways : either from a blastema, proto-
plasm, or formative substance existing with-
out, or contained within, other cells. The
protoplasm is a semifluid substance, consist-
ing of proteine or albuminous matter, fatty
matter and salts.

The formation of cells in a free blastema
is not a general process ; in fact, its occur-
rence is now mostly denied. The only in-

Fig. 104.

Magnified 350 diameters.

Contents of a Malpighian body from the spleen of an
ox. a, small, 6, larger cells; c, free nuclei.

stances of its supposed occurrence in man
and the higher animals were in the forma-
tion of the chyle and lymph corpuscles, the
cells of certain glandular secretions (seminal
cells, ova), and glandular organs (the closed
follicles of the intestine, the lymphatic
glands, the splenic corpuscles with the
splenic pulp, and the thymus) ; lastly, of
tne cellular elements in the impregnated
uterus, in the corpus luteum, the marrow of
foetal bones, and in the soft ossifying bias-

CELL.

[ 139 ]

CELL.

temata. In the case of the chyle and the
spleen, at the commencement of cell-forma-
tion, there occur roundish, apparently homo-
geneous bodies of 1-11000 to 1-5600" dia-
meter, which, increasing in size, soon appear
distinctly as vesicles (fig. 104), and, on the
addition of water, exhibit an internal large
body resembling a nucleolus, as also several
granules. The minute details of this stage
of the process of formation are not accu-
rately known. As soon as the nuclei are
formed, cell-membranes are formed around
them, but not always in the same manner.
Sometimes the cell- wall is deposited directly
around the nucleus, so that it is but little
larger than the latter ; at others the nucleus
becomes surrounded by a larger or smaller
quantity of protoplasm which becomes more
solid, and around which the cell-membrane
is subsequently deposited. The latter oc-
currence has hitherto only been satisfacto-
rily observed in the case of the ovum, in
which the germinal vesicle, i. e. the nucleus
of the ovum-cell, which is formed first,
becomes surrounded by a quantity of yelk,
before the vitelline membrane is formed.
On the other hand, the formation of the
cell-wall directly around the nucleus has
been supposed to take place in all the other
localities mentioned above ; and to be espe-
cially shown by the occurrence of free
nuclei and larger cells, together with very
small cells closely surrounding the nuclei,
or separated from them by a slight interval
only. It is possible that, in this instance
also, the cell-membrane, even at its first for-
mation, may be separated from the nuclei
by a quantity of protoplasm too minute to
be detected.

The free formation of cells has been ob-
served by Weissmann in insects during de-
velopment.

The extracellular formation of cells is
unknown in plants. And probably, when
observers are agreed, it will be found that
all protoplasts and cells are derived from
parent protoplasts by some form of segmen-
tation.

The endogenous method, or the formation
of cells within others, is very common, and
may be readily observed in the tissues of
embryos. In the most ordinary form of this
kind of cell-formation, an original or parent-
cell produces within it two secondary cells,
which from the first completely fill it. The
first phenomenon observed in the parent-
cell is the increase of the nucleus, which
acquires two nucleoli, becomes elongated

and resolved into two nuclei. After this
the nuclei separate from each other, and a
partition is formed between the cells, di-
viding the parent cell into two perfectly
distinct spaces, each of which encloses a
nucleus and half of the contents (tig. 100).
The exact manner in which the increase of
the nucleus occurs is not certain ; but it ap-
pears that the nucleoli always become re-
solved into two by subdivision, and then
separate from each other. In the nuclei,
which at the same time become elongated,
the first trace of division is then usually a
median partition, which in favourable in-
stances appears to arise from the presence
of two secondary cells in close contact by
plane surfaces and entirely filling up the
parent nucleus. Very frequently nothing
is seen but first an elongated nucleus with
a partition and two nucleoli, and then two
hemispherical nuclei in contact by their
plane surfaces (fig. 105), no endogenous

Fig. 105.

Magnified 3cO diameters.

An elongated nucleus, and one containing two secon-
dary nuclei, from the OTum of an Ascaris dentata.

nucleus-formation being perceptible ; in this
case, division of the nucleus has taken place,
the parent-nucleus containing two nucleoli
becoming finally resolved into two by a
deeper and deeper constriction. This mode
of cell -formation is often continuously re-
peated, frequently so long as the growth of
the organism continues. The parent-cells
then either continue their existence as such,
or they disappear sooner or later as histo-
logically distinct formations, and become
consolidated with the substance connecting
the cells.

The endogenous cell-formation, which
agrees essentially with the formation of
cells in a free protoplasm, is well established
in the case of the young cartilages of all
animals ; it also probably occurs in embry-
onic organs in general, in which, from the
period at which they consist of true cells,
the entire growth depends upon the multi-
plication of the existing cells without free
cell-formation. It also occurs in patholo-
gical products, as in cancer.

In addition to this — the most common

CELL.

[ 140 ]

CELL.

kind of endogenous cell-formation, there are
others, viz. : —

a. In the ova of most animals at the earliest
period of development, a peculiar process
occurs called the segmentation of the yelk,
which must be regarded as preliminary to
the formation of the first embryonic cells;
and which, as the ovum hears the import of
a simple cell, falls under the type of endo-
genous cell-formation. The essential fea-
tures of the segmentation are as follows.
After the original nucleus of the ovum-cell
— the germinal vesicle — has disappeared in
consequence of impregnation, the granules
of the yelk no longer remain aggregated
into a compact mass as before, but become
distributed throughout the entire cell. The
first sign of commencing development is
then constituted by the formation of a new
nucleus — the first embryonic nucleus,around
a new nucleolus, which acts as a centre of
attraction to the yelk, and causes it to re-
unite into a globular mass — the first glo-
bule of segmentation. In further develop-
ment, two new nucleoli are formed from the
first nucleus by endogenous growth, which,
as soon as they are set free by the develop-
ment of the parent nucleus, become separate
from each other, act as new centres to the
yelk-granules, and thus the first globule of
segmentation becomes resolved into two.
The increase of the nuclei and of the glo-
bules of segmentation continues in the same
way, the first always preceding, until a very
large number of small globules are present,
which entirely fill up the yelk-cell ; some-
times, but exceptionally, the globules are
not resolved until the nuclei have become

Fig. 106.

Fig. 108.

Magnified 350 diameters.

Three ova of an Ascaris nigrovenosa : 1, in the first'
2, in the second, and 3, in the third stage of segmenta-
tion, with two, four and sixteen segmentation-globules.
c, outer coat of the ovum ; b, segmentation-globules.
In 1, the nucleus of the lowest globule contains two
nucleoli ; in 2, the lowest globule two nuclei.

increased to three or four, so that three or
four globules are formed from each, instead
of two. This process is termed total seg-

mentation, because here the entire yelk is
applied to the newly-formed nuclei : partial
segmentation agrees with this in all essen-
tials, and only differs from it in the circum-
stance that in it, not the whole of the yelk,
but a larger or smaller part of it, varying in
different animals, envelopes the nuclei in
process of formation (figs. 106-108).

When the process of segmentation has
reached a certain stage, the segmentation-
globules become surrounded with mem-
branes and form true cells, whence it ap-
pears j ustifiable to arrange this process with
endogenous cell-formation. In fact it is
nothing more than a preliminary to cell-
formation in the ovum-cell, and only differs
from the ordinary phenomena of this kind
in the circumstance that — first, the nucleus
of the parent-cell or the germinal vesicle in
most cases has nothing to do with it ; se-
condly, the parent-cell itself persists ; and,
thirdly, the portions of the contents formed
in it by the successive increase of nuclei do
not assume the form of cells until subse-
quent generations. This view is moreover
justified, since the cells formed from the
last segmentation-globules continue for a
long period to multiply by endogenous pro-
duction (or division) ; and the entire seg-
mentation-process may be regarded as a
kind of endogenous cell-formation, in which,
on account of the rapidity with which the
nuclei increase, in the first generation of
globules it does not come to the formation
of membranes (see OVUM).

b. In some respects allied to segmentation,
are those forms of endogenous cell-forma-
tion in which a greater or less number of
secondary cells are formed within persistent
parent-cells, as seen here and there in carti-
lage, the suprarenal capsules, the pituitary
body, &c. In this case, either two second-
ary cells are formed in the usual way in a
cell, almost or entirely filling it, and from
these other generations, either free or all or
individual ones enclosed in parent-cells of
the second and subsequent generations, or
only one secondary cell is formed in a cell,
whence cell-formation then proceeds in
either manner (fig. 109), or the secondary
cell is formed in a bud-like protrusion of the
parent-cell (see ECHINOCOCCUS).

The formation of a larger number of
nuclei within cells, which frequently pre-
cedes cell- formation, but may also exist
alone, may be well arranged under endo-
genous cell-growth. Even in ordinary en-
dogenous cell-formation (and also in seg-

Magnified 350 diameters.

Cartilage-cells from a fibrous velvety articular car-
tilage of the condyle of a human femur ; all lying in a
fibrous basis, and easily isolated, a, single cells, with
or without thickening of the cell-wall, and one or two
nuclei : b, secondary cells, or cells of the first genera-
tion, with one or two nuclei — one, two, five, and many
cells in the parent-cells 6'; c, cells of the second gene-
ration, one to three in those of the first, bb; d, free
group of secondary cells.

mentation) we not unfrequently find three
and four nuclei in one parent-cell, so that
then, instead of two, a larger number of se-
condary cells are formed at once, as e. g. in
the liver-cells of embryos. In certain ani-
mals ( Cucullanus, Ascaris dentata, Distoma,
and the Cestoidea), instead of segmenta-
tion-globules, in the first stage of develop-
ment, nuclei only are formed in the ovum-
cell, which do not become surrounded by
cell-membranes until they have accumu-
lated into a large heap by successive endo-
genous growth. The same appears to take
place in the cells of the germ of the Crus-
tacea, in which from ten to twenty nuclei
frequently exist. The numerous nuclei,
however,* in the seminal cells of most ani-
mals appear usually to have DO connexion

CELL.
Fig. 110.

Magnified 350 diameters.
Ivory-cells from the tooth of a dog.

with cell-formation, because the
seminal filaments are developed
within them; and the same applies
to those cells of the lower animals,
the numerous nuclei of which are
converted into urticating organs.
Whether in these cases the nuclei
multiply by division or endogenous
growth is unknown.

Cell-formation by division has been ob-
served in the coloured blood-corpuscles of
the embryos of Birds and Mammalia, and
the earliest colourless blood-corpuscles of
the larvae of frogs (tadpoles) j it also pro-
bably occurs in the colourless blood-cor-
puscles of embiyos and the chyle-cor-
puscles of adult Mammals. In all these
cases the cells first become elongated, and
the single nuclei appear to become divided
into two ; the cells are then constricted in
the middle and finally resolved into two,
each with a nucleus (PI. 49. fig. 36).

A peculiar kind of cell-growth, most
nearly allied to division, occurs in the cells
of the ivory of the teeth ; in which the nu-
clei, while continually elongating, enlarge
from time to time and become constricted,
so that whilst that portion next the ivory
ossifies, the remainder serves to a certain
extent as a reserve for the subsequent for-
mation of newly ossifying portions (fig. 110).
The term cell is frequently used in a
totally different sense, to denote a partially
closed space, or the cup-like body enclosing

CELL.

[ 142 ]

CELL.

the space ; as in the case of the cells of a
Polype, or Polyzoon, the cells of a sponge,
&c.

BIBL. Treatises on Physiology ; Schwann,
Einstimmung (Syd. Soc.}; id. Wagner's
Physiol. ; Valentin, Phys. ; Kolliker, Ge-
webelehre d. Menschen (and the Bibl. there-
in) ; Siebold, Zeitschr. f. wissem. ZooL i.
p. 270; Rollett, Strieker's Handbuch (Syd.
Soc.) i. ; Frey, Histologie, and the Bibl.) ;
Cohnheim, Virchow's Archiv, xl. ; Reck-
linghausen, ibid, xxviii. ; Weissmann,
Zeitsch. f. rat. Med. 3rd ser. xv. ; Klein,
Qu. Mic. Jn. 1878 and 1879, and Hist, ;
Carpenter, Phys. ; Strassburger, Zellenbil-
dung, 1880 ; and the Bibl of TISSUES.

CELL, ANIMAL, artificial formation of. —
When oil is immersed in a liquid containing
albumen, it becomes surrounded by a layer
of coagulated albumen, forming a cell ; and
this cell will exhibit the phenomena of en-
dosmose and exosmose in the same manner
as any natural cell. The same phenomenon
has been observed with metallic mercury and
albumen, chloroform and albumen, chloro-
form and chondrine, &c. It has not yet
been satisfactorily explained. The natural
formation of cells has been supposed to be
produced by this method j but it appears
inapplicable to the purpose, as the nuclei or
masses of blastema, around which natural
cells are formed, do not consist of fat.

See CONCRETIONS.

BEBL. Ascherson, Mailer's Ai'chiv, 1840,
p. 44, &c. ; Wittich, De hymenogonia albu-
minis, Regiomont. 1850 ; Harting, Neder.
Lane. Sept. 1851 ; Melsens, Bull, de VAcad.
de Belg. 1850 ; Panum, Archiv f. path. An.
iv. 2 j Bennett, Ed. Mn. Jn. viii. 166 ; Kol-
liker, Geweb. d. Mensch. 10; Schmidt,
Taylor's Scientific Memoirs, v. 10.

CELL, VEGETABLE. — The definition of
the term cell in vegetable anatomy, ordina-
rily adopted, is, a closed sac composed of an
(originally) imperforate membrane formed
of the chemical substance called cellulose,
this membrane enclosing more or less fluid
contents so long as the cell retains its vi-
tality. All the solid permanent structures
of plants are formed of cells answering to
this character, the differences of the full-
grown tissues depending upon peculiar
modifications and alterations of the original
cells. In animal structures, the term cell
is commonly applied, not only to structures
really analogous to the cells of plants, but
also structures analogous to the contents of
the true cellulose plants, which, however,

are indeed in all cases the important vital
parts of the structure. All young vegetable
cells contain a quantity of semitluid nitro-
genous formative substance called proto-
plasm, which may be chiefly adherent as a
thickish and more or less continuous layer
on the inside of the cellulose wall, forming
a kind of lining to it, and therefore en-
closing all the rest of the contents, in which
case it forms the primordial utricle of Mohl ;
or this dense protoplasm may fill up the
whole cavity of the cell as a gelatinous
mass. Or the gelatinous mass of proto-
plasm may emerge from the cellulose sac,
with a definite form and organization, fur-
nished with cilia enabling it to move freely
in water ; and here the protoplasm presents
itself as independent, and indeed as the pri-
mary element of all cellular tissue : it occurs
in this condition in the zoospores of the
Confervoid Algae. These free bodies, de-
void at first of a cellulose wall, are evidently
analogous to the corpuscles of ' sarcode '
constituting certain animals, such usAmosba,
while the cartilage-cells &c. of animals are
analogous to the cellulose sacs of plants.

In this work, then, the word cell, as ap-
plied to organic structures, is always used
in its ordinary sense. Hackel's unnecessary
terms Cytode for the simple protoplast, and
Cell for the nucleated protoplast, are ignored
in botanical works.

Form. — Cells may present almost every
possible modification of form ; and this
depends on two sets of conditions — the ori-
ginal development and shape, and the mode
of growth and expansion. It is frequently
stated that the primary form of all vege-
table cells is that of a sphere, or at all events
that this is the type, from which all the others
must be considered deviations. This is true
only so far as it is intended to signify that
most cells which originate free in the midst
of fluid, suffering no external compression,
have a globular form ; and that in numerous
cases where cellular tissues are very lax and
free to expand in all directions, the compo-
nent cells acquire a globular form during
the enlargement to their full size. But in a
very large majority of cases the cells do not
originate in a free condition, they are pro-
duced by subdivision of older cells, and
consequently, when first developed, they
have the shape of the half, the quarter, or
whatever segment it may be of the parent-
cell ; moreover, in a majority of these cases
the mode of expansion also depends upon a
special law of the particular tissue, or even

CELL.

[ 143 ]

CELL.

of such tissue in the particular group to
which the plant belongs, and not upon any
general law of globular expansion. The
above law does prevail widely in some fami-
lies, as in the Fungi ; and we very frequently
see it prevailing in pith up to a certain period :
but it will not hold as a general rule ; for the
lax tissues of leaves, of succulent stems, &c.
offer most striking deviations, as do also the
varied and often elegant forms of lower
Algae. It is frequently stated in books,
that the effect of pressure on cells having a
tendency to become globular, is the produc-
tion of a dodecahedral form ; but this again
is far too sweeping a generalization, and the
real fact is that globular cells of equal size,
expanding in a confined space, often become
twelve-sided by mutual pressure ; but far
more often the cells of a tissue are of diverse
size, and hence a polyhedral form is much
more common (tig. 111). Cells may be

Fig. 111.

globular, as in the Yeast-plant, and many
lower Algae, in the lax tissue of young pith
of many Dicotyledons (PL 47. tig. 14), &c. ;
oval, as is much more common in parenchy-
matous tissues; squarish, as in cork (PL 47.
figs. 16, 17) ; or tabular, as in the epidermis
of numerous plants, under wThich circum-
stances the side walls may be square,
rhombic, hexagonal or irregular, as in many
petals ; and the outlines may
also be undulated or even Fig. 112.
beautifully zigzagged, as in
the leaf of Helleborus fcetidus
&c., the petals of many
flowers, or in the leaf of the
Pineapple (PL 47. fig. 15),
&c. ; while the upper exposed
face may be flat or vaulted,
as in most petals, or even
papilliform, as in the petals
of the Sweet William and
of most flowers with glisten-
ing surface. Cells may also be cylindrical,
and then either with flat ends (fig. 112),
as in the parenchyma of many Monocoty-
ledons and in the filaments of Confervas, or

rounded ends or attenuated ends, as in wood
and liber tissue generally ; or they may
be prismatic, and then square or six-sided,
as in stems of most herbaceous plants ;
spindle-shaped, as in a large number of
woods, such as that of Conifers, Box,
&c. ; and, in fact, of almost every con-
ceivable form. In lax tissues, the walls
of the cells often grow very unequally at
different points, whence result angular pro-
jections, by which the cells ordinarily co-
here (fig. 113) ; or these grow out into
arms or rays, producing stel-
late cells, as in the pith of -p- -j -j o
the Rush (PL 47. fig. 18),
and the parenchyma of many
aquatic plants, in the leaf-

stalk of the Banana, &c.

Cells which are free, as in . y^

the lower cellular plants, "7 /\J^? j
sometimes grow out into ^\ ..-. j
long tubular structures such <J\J

as Vaucheria, with a conti-
nuous cavity, and indeed sometimes ramify
into a complication of branches, as in £ry-
opsis and Codium, while in Botrydium (fig.
75) the globular cell sends down a number
of root-like filaments which are mere pro-
trusions of its own wall. The cells of Chara
attain very large size. In the Flowering
plants we have an example of extraordinary
growth of a single cell in the* pollen-tubes,
which, in some cases, become as much as
three inches long.

Size. — The dimensions of cells vary to
infinity, and, indeed, often extremely in one
and the same tissue, but not as a rule. And
the diameter of cells is very frequently in-
comparably less than the length, as in all
filamentous and fibrous cells. Taking a very
general view, we may say that parenchyma-
cells vary from 1-250 to 1-1000" in dia-
meter ; but the spores of many Fungi mea-
sure no more than 1-6000 to 1-8000", while
the cells of the juicy parenchyma of many
fruits and piths attain as much as 1-100".

The smallest cells appear to occur in
Palmella hyalina, where they measure the
1-83,000". In elongated cells, such as those
of liber and most woods, the diameter is
ordinarily less than in parenchyma, while
the length is far greater : thus in wood the
length varies from about 1-40 to 1-12'',
while the diameters are respectively 1-300
and 1-100"; in liber the length may extend
to 1-8 or 1-4", with a diameter of 1-800 and
1-400". (See FIBRES.) Hairs composed
of a single cell often attain a great length,

CELL. [ 1

as in Cotton, where a single filamentous
cell may measure 1 to 2". (See TISSUES,
VEGETABLE.)

Cells may be examined either in situ, as
parts of tissues, or free, separated naturally
or artificially. For the first it is simply
requisite to make fine slices with a razor, in
various directions through the structure ; if
soft or thin, it should be placed between the
two halves of a split vial-cork and sliced with
the cork, the cork being afterwards removed
from the slide with a needle. Slices of many
kinds of cellular tissue are made more clear
by the addition of a little diluted sulphuric
acid, which, however, often swells up some
of the layers.

For examining isolated or nearly separate
cells, we may take the lower Algae or Fungi,
or germinating spores of the higher plants,
or we may separate the cells of the tissues of
higher plants. The parenchymatous tissues
may usually be separated into their elemen-
tary cells by maceration in water : the de-
composing ends of flower-stalks which have
been in water several days will generally
afford tissue in such a state that it may be
broken up with a needle ; in the pulp of ripe
fruits, such as currants, strawberries, &c.,
mere pressure separates the cells. Boiling
will do with some of the denser kinds ;
while for the woody tissues it is requisite to
heat fragments witn a particle of chlorate
of potash and a drop of nitric acid (or let .
them macerate for 1 2 to 24 hours), and wash
them well with water: liber-cells, woody
cells, &c. may be isolated by this means ;
or still better'by treating them with chromo-
sulphuric acid.

formation of Cells. — This subject has
undergone a great amount of investigation
during the last few years ; and the views
which have been propounded at various
times have conflicted strongly in many
points. It would be exceeding our limits,
however, to enter upon a critical examina-
tion of the theories of cell-development;
and we shall therefore confine ourselves to
a brief account of those phenomena and
laws of the reproduction of cells upon
which the diversity of opinion only affects
subordinate particulars.

All vegetable cells (using this term in the
sense of the cellulose sac with contents, as de-
fined above) in which the capacity for repro-
duction exists, contain an internal structure
or protoplasm, varying in its condition and
appearance at different epochs and in dif-
ferent plants or parts of plants. This struc-

4 ] CELL.

ture often forms a semifluid layer lining the
cellulose wall of the cell. All the other
cell-contents are enclosed or imbedded in
thi s protoplasm ; and with it they collectively
constitute what is called by some authors
the endochrome of the cell.

In a very large number of cases, we find
in the protoplasm at this time, a peculiar
body called the nucleus, to which some
writers attribute great importance in the
development of cells. Its nature is not
well defined ; but in the best-observed cases,
it consists of a small globular or lenticular
mass,apparentlv composed of the protoplasm
in a condensed and granular (solid) con-
dition. The nucleus is usually present in the
cells of the higher plants, but is often ab-
sent in those of the Thallophy tes. It mostly
exhibits one or more bright granules or
points in its substance, which are called
nucleoli. Many authors consider this body
of the first importance in cell-development ;
but as we are by no means satisfied as to
the character of its agency, its peculiarities
and its relation to the "cell are spoken of
separately under the head of NUCLEUS
(PI. 47. figs. 8,9 n).

The ordinary development of new cells
depends upon the division of the protoplasm
of existing cells into two or more portions,
which, becoming independent centres of
life, produce new cellulose membranes, and
become new cells. The phenomena in which
this law is manifested are far more varied
than would be imagined from this simple
statement. The numerous subordinate mo-
difications, however, maybe arranged under
three principal heads : — 1. Cell-division,
sometimes called merismatic cell-formation;
2. Cell-division with liberation of the new
cells ; 3. Free cell-formation.

1. Cell-division is the process which occurs
in all reproduction of cells connected with
vegetative growth or increase of the mass of
existing structures. This is the manner in
which the cells are multiplied in the growth
of the thallus of the inferior plants, and in
the growth of the stems, leaves, roots, and
other organs of the higher plants. It occurs
also in the formation of the basidiospores or
stylospores of Fungi, the spermatia of these
and Lichens, of gonidia in the Lichens, and
conidia in the Fungi. The essential fact
observed in all the cases is, the division of
the protoplasm of the parent- cell into two
or more distinct portions, each of which
secretes a layer of cellulose over its whole
surface ; and thus, when the two are in ap-

CELL.

[ 145 ]

CELL.

position, a partition i,« formed dividing the
parent-cell into two or more parts. The
form of the secondary cells depends of course
on that of the parent-cell at the time of
division. In the case of cellulose tissues,
such as those in the ynmctum vegetatioms of
thebudsof the higher plants. incaw?&««w,&c.,
the division is ordinarily into two parts,
which respectively grow until equal in size
to the parent ; and either both or only one
of these divides again in the same way, and
so on, until the whole structure is com-
pleted. It is evident that the external
forms of all cellular structures must depend
greatly upon the laws of division of the
cells of plants. For example, supposing we
start from a single square cell, when this
divides into two halves, and these grow to
equal the parent-cell, we have an oblong
figure ; if the half-cells divide again in the
same direction, we shall in time get a long
filament ; and if both new cells divide again
each time, the filament will grow much
longer in a given time than if only the end-
cell continually divided, leaving one new cell
behind it at each division. If the pair of
cells produced by the first halving divide at
right angles to the first division, a square
group of four cells results ; and if this law
continues to act, a flat plate of cellular tissue
will result. Further, if the cells also divide
by horizontal partitions (in the third direc-
tion of space), the mass of cells will gradually
acquire thickness or height as well as length
and breadth. Lastly, if the cells of parti-
cular regions cease to divide sooner than
others, irregular or complex but definite
structures will be produced — as those parts
where the cell-division goes on will emerge
from the general mass, in the Cellular plants
as lobes, and in the higher plants as conical
bodies which are gradually developed under
similar laws into the organs. The diver-
sities of internal organization depend also
to some extent on the same laws, but less on
these than on the laws regulating the forms
which the cells acquire when full-grown.

Cell-division may be observed most easily
in the lower Cellular plants, or in the simpler
structures (such as hairs) of the higher plants
(PI. 47. figs. 8, 9). The Confervas afford
exceedingly favourable opportunities, as do
also the filamentous or thalloid structures
of germinating Mosses, Ferns, microscopic
Fungi, &c. The behaviour of the parent-
cell before division exhibits some diversities.
If a simple filament is increasing by cell-
division, the cylindrical parent-cells merely

elongate a little before dividing transversely.
If the filament is to branch, the wall of the
parent-cell bulges out gradually at the point
where the branch is to appear ; the bulging
soon becomes a pouch, and this pouch is
soon shut oft' by the formation of a partition
at its base. Bead-like rows of cells likewise
divide by budding in this way, as may be
observed, for instance, in the Yeast-plant :
the new cell first appears as a little 'bubble '
on the side of the parent, with its cavity
continuous ; and after it has acquired a
certain size, its protoplasm detaches itself
from that of the parent, and a partition is
formed at the point whence the second cell
emerged (PL 26. fig. 23).

Another point which must be noticed
here, is the question whether the parent
protoplasm divides instantaneously, at a given
epoch, into the new utricles, or whether it
parts gradually, by a sort of constriction ad-
vancing from the surface towards the centre,
roughly comparable to what occurs when a
ligature is slowly drawn tight round an
elastic tube, or w,hen a bar of soap is cut in
two by passing a string round it and gra-
dually drawing the loop tight. It seems
probable that the segmentation of the pro-
toplasm is always gradual ; and it is certain
that it is so in many cases. Its gradual
constriction has been observed in those
Confervas where the protoplasm forms a
hollow sac, lining the whole internal sur-
face of the parent-cell ; it may be traced in
the larger Confervas, in Spirogyra, &c., by
keeping the plants growing in water under
the microscope. It appears that the division
is generally completed during the earlier
hours of the morning.

2. Cellr-division with liberation of the new
cells. — The first step in this process is ana-
logous to what takes place at the outset in
the preceding set of cases; but we find
much more important modifications here.
This is the mode of development of spores
of the Ascomycetous Fungi, of the spores
and tetraspores of the Algas, the spores
of Lichens, the spores of all the higher
Cryptogamia, the active gonidia or zoospores
of the Algee, the parent-cells of the sper-
matozoids or active spiral filaments of the
higher Cryptogamia, and of the pollen-grains
of the Flowering plants.

The general character is : Division of the
whole protoplasm into segments, which
either acquire a cellulose eoat within the
parent-cell before they are set free by its
solution or bursting, or escape from the

CELL.

[ 146 ]

CELL.

parent-cell -without a cellulose coat, and
secrete this afterwards.

The following modifications occur : —

a. Division of a nearly solid protoplasm
into four, either directly or by two
halvings. This occurs in the development
of pollen and of the spores of Mosses, Ferns,
&c. The parent-cells of the pollen or spores
become free in the interior of the anther or
sporange, by the solution of the walls and
septa of their parent-cells. The protoplasm
of the free cells divides into four segments,
entirely filling the cell. After this, either
partitions are formed between these (pollen-
cells), to be subsequently dissolved, or they
at once clothe themselves with a cellular
coat (Marchantia). In either case, they
ultimately lie free in the parent-cell, which
is itself finally dissolved (PI. 47. figs. 10-13).

b. Division of a homogeneous protoplasm
into a large number of segments, each of
which acquires a cellulose coat, the whole
of the new cells lying closely packed but
free in the parent-cell. This occurs in the
antheridia of the higher Cryptogamous
plants, in the formation of the parent-cells
of the spermatozoids, also in the formation
of the parent-cells of the spores and the
elater-cells of the Hepaticse. The formation
of the spores in the asci or thecae of the
Ascomycetous Fungi and the Lichens be-
longs either to this or the preceding case
(PL 37. fig. 12).

c. Division of the homogeneous proto-
plasm into segments which do not acquire
a cellulose coat until after they are dis-
charged from the parent-cell. This occurs
in the development of the zoospores of most
of the Confervoidese (Oladopharat£ryop9Uf
Achlya,) Ulothrix, &c.), where the primor-
dial utricles become free in the cavity of
the parent-cell when they divide, and break
their way out into the water, where they
form a cellulose coat after they have swum
about freely for some time by means of
their cilia.

d. Division of a sac-like protoplasm into
a number of portions, which appear at first
as papilla on the walls of the cell, and
finally become isolated in the cavity. This
occurs in the development of the gonidia
of Hydrodictyon, Eotrydittm, &c. These
last two cases are connected with a and 6,
by the circumstance that the zoospores or
active gonidia are replaced, under certain
circumstances, by cells ; that is, the bodies
produced in this way acquire a cellulose
coat before they leave the parent-cell.

Numerous intermediate conditions occur
which connect all these together; and the
last case, d, does not differ essentially from
what takes place in the formation of the
endosperm-cells, placed under 3.

3. Free Cell-formation. — Here the new
cell is formed by a portion of the parent
protoplasm separating itself from the rest
of the protoplasm, assuming a globular or
oval form, and secreting a cellulose mem-
brane upon its surface, so as to form a new
cell lying free in the cavity of the parent
primordial utricle. The most remarkable
instance of this case is the formation of the
germinal vesicles in the embryo-sac of the
Flowering Plants (PI. 47. figs. 1-4) ; but
this is denied by Strassburger. Other cells
sometimes occur, formed in the same way,
at the opposite end of the embryo-sac.
The embryo-sac also frequently becomes
filled, after fertilization, by a large increase
of free cells developed out of the layer of
protoplasm or primordial utricle lining the
walls; these (endosperm-cells) accumulate in
the sac, and sometimes become consolidated
into a tissue (albumen) in which the embryo
lies imbedded ; in exalbuininous seeds they
are re-absorbed during the growth of the
embryo. The embryo itself is developed from
the germinal vesicle by cell-division such as
is described under § 1 (PI. 47. figs. 5, 6).

Cell-formation also occurs, without divi-
sion, in cases where the entire contents of
a cell separate from the parent, and form a
new organism (rejuvenescence) — as in Sti-
geoclonium, (Edogonium, and other Con-
fervoid Alga3.

Here also must be referred the new cell-
formation resulting from CONJUGATION.

Karsten considers that the formation of
every cell within a living organ is original ;
and that the cell is not divided into two
new individuals by transverse septa or pro-
liferation.

The hypotheses of the independent origin
of cells from organic substances \xygeneratio
cequivoca seem to require no notice; but
allusion may be made to certain curious
phenomena which have been called t abnor-
mal cell-formations/ occurring in some of
the Confer voids. The protoplasm of the
Siphonese is verv apt to collect into globu-
lar masses in injured filaments ; and these
globular masses apparently acquire a cellu-
lose coat in some cases : they have been
observed in Vaucheria tmd Bryopsis ; a some-
what similar phenomenon often occurs in
the contents of the cells of Spirogyra. It

CELL.

[ 147 ]

CELL.

appears to be a kind of gonidial reproduction,
in which portions of the living contents
are enabled to save themselves from the
general decomposition. (See PSEUDOGO-
NIDIA.) Some forms which we incline to
refer here, have been described as distinct
genera and species of parasitic Algae ; on
this subject see PARASITES, CHYTRIDIUM,
PYTHIUM, and AMYLOBACTER.

Membrane. — In all young organs of suc-
culent structures, and all the delicate tissues
of the higher plants, and in the majority of
the Cellular plants in almost the entire or-
ganization, the cellular membranes consist
of a thin structureless pellicle, possessing a
considerable degree of toughness and a
certain amount of elasticity. (C. J. Agardh
has indeed asserted that cell-membrane is
composed of spiral fibrous structure ; but
this doubtless is an error as regards the pri-
mary membrane.) It is readily permeable
by water, while no orifices of any kind can
be detected in it ; but young, and indeed
soft cell-membranes generally, imbibe more
or less water, and swell to some extent,
often becoming more or less gelatinous. It
is stated by Schleiden that the membranes
of nascent cells are soluble in water, but
general experience does not confirm this
statement ; the only approach to a corro-
boration of it that we have met with, is in
the lower Algae : the zoospores are often
extruded in the interior of an extremely
delicate sac formed of cellulose, which al-
most immediately vanishes and sets the
zoospores free. The external membranes
of many of the filamentous and unicellular
Algae become gelatinous, and gradually dis-
solve away as the inner membranes are
successively deposited, forming a gelatinous
coat, as in Protococciis, Nostoc^ Desmidia-
ceae, Diatomaceae, Zygnema, Oscillatoriese,
&c. ; the same also takes place in the de-
velopment of spores and pollen-grains, which
are set free by the parent-cell membranes
becoming dissolved. This, however, is
scarcely direct solution in water, and conies
rather under the head of decomposition.

Young and delicate cell-membranes are
perfectly transparent and colourless, as is
seen in the Yeast- plant, in the mycelium of
Mildews, in the cellular tissue of tuberous
structures like the Potato, and in piths (after
the mucilaginous cell-contents have been
removed). As they grow older, they often
become coloured, sometimes very deeply,
which is supposed, however, to depend on
the infiltration of foreign matters. In the

state of simple cell-membranes, where no
infiltration of foreign matter has occurred,
the application of sulphuric acid of moderate
strength, with solution of iodine in solution
of iodide of potassium, brings out a bright
blue colour : and this is regarded as a test
for cellulose, the universal basis of vegetable
cell-membrane.

When the cell has attained a certain age,
new deposits of membranous substance take
place inside; and the walls thus acquire
more or less thickness, together with a
very varied appearance, according to the
character of the deposits. The new layers
are known as SECONDARY LAYERS j and the
term Cell-watt is perhaps the most conve-
nient collective term which can be applied
to the various structures produced by the
deposition of new layers of cellulose upon
the inside of the primary cell-membrane.
Although these new deposits are thin layers
of cellulose like the primary membrane, they
are rarely so totally devoid of detail struc-
ture, and in the majority of cases exhibit
orifices and irregularities of the most striking
character. Moreover, in one class of cases,
they are not deposited as a continuous coat,
but as a fibrous structure applied upon the
primary membrane, as in spiral-fibrous cells ;
and in wood-cells they are formed one within
another to such a thickness that the cell-
wall loses its original membranous character,
and becomes a solid case, with the internal
cavity reduced to a comparatively small
chamber in the centre.

The simplest condition of a thickened
cell-wall, is that met with in the unicellular
and filamentous Algae, where the primary
membrane becomes coated in the interior by
successive continuous layers of cellulose
exactly resembling itself, and which often
indeed can only be known to exist by com-
paring the thickness of old and young cells,
since no lamellation can be detected ; gene-
rally speaking, however, the action of mode-
rately diluted sulphuric acid swells up such
membranes, and renders the lamellae more
or less distinct (PL 47. fig. 24). The thicken-
ing layers of the unicellular and filamentous
Algae are scarcely to be compared with those
of the cells of higher plants, since they are
rather to be regarded as the primary mem-
branes of new cells produced in the interior
of the older cells, in many cases set free by
the solution of the latter. These cell-waDs
sometimes exhibit peculiar fibrous appear-
ances. See SPIRAL STRUCTURES.

These layers may be coloured blue by
L 2

CELL.

[ 148 ]

CELL.

sulphuric acid and iodine ; when very young,
even by iodine alone; but when old or where
they undergo spontaneous solution into a
kind of jelly, as in filamentous Algse, this
cellulose reaction seems to fail — at all events
it is so uncertain in its behaviour, that,
although it gives a positive result in suc-
cessful cases, a negative result is altogether
inconclusive.

In the cells of the generality of plants of
higher organization, the secondary cell-
membranes exhibit a striking difference
from the primary, inasmuch as we find them
constantly perforated by holes, slits, or
orifices of some shape, so as to leave the
primary membrane bare ; whence results a
spotted or streaked appearance of the cell-
wall, as may be seen even in cells with the
walls still very thin, such as fully-formed
pith-cells of the Elder.

The earlier vegetable anatomists regarded
these spots or dots as orifices through the
cell- wall ; but they are in reality only pits
opening into the cavity of the cell, and closed
externally by the original membrane of the
cell. When the cell-wall becomes much
thickened, as in cells of horny albumen or
wood-cells, the layers successively deposited
over the inside mostly correspond pretty
exactly with the earliest layers, and leave
the spots always free, so that these become
gradually converted into tubular canals run-
ning through the thick cell-walls (PI. 47.
figs. 21-23 and 27). In the majority of
cases, but not in all, the spots or pits in the
cell-wall are opposite to similar spots in
the walls of the adjacent cells, so that the
cavities of the two contiguous cells are only
separated from each other by the primary
membrane of each, as at first, allowing free
permeation of fluid from one to the other.
In old cells these primary membranes be-
come destroyed, and thus the cavities
communicate freely through these canals
running out through their hard thickened
walls. The various complications of these
pits are spoken of under the head of PITTED

CELLS.

The secondary layers are further distin-
guished from the primary membrane by
the prevalence of a tendency to assume the
character of spiral bands or fibres winding
upon the original cell-wall. This may be
detected even in many cells which remain
quite membranous, as in some Conferva anc
many hairs, also in pitted lignitied cells,
where the thickening layer forms a genera
coat upon the inside of the cell ; the liber-

cells of man;
striation of their walls, while some liber-cells
display it with especial distinctness. Some
of these cells give way in a spiral direction
when torn by pulling lengthwise. In par-
enchymatous cells this spiral structure is
often very fully developed in all its varieties ;
but it is especially characteristic of the
vessels and ducts ; while in certain woods,
as in TAXUS, we have a combination of the
porous with the spiral secondary deposits,
the earlier thickening layers leaving spots
uncovered while the latter ones are deposited
along a spiral line coiling up the cell-wall
from bottom to top, and thus the cell
appears to have a spiral fibre lying upon its
walls. These structures are spoken of at
length under the heads of SPIRAL DEPOSITS
and PITTED CELLS.

Cellulose is distinguished, when in the
form of membrane or fibrous structure, by
the blue colour it usually assumes when
treated with iodine (starch differs in its
granular form and its solubility in acids and
potash, and its swelling up in hot water).
The nitrogenous protoplasm is always co-
loured yellow-brown by iodine. The blue
colour appears in many membranous paren-
chyinatous tissues when the cells are soaked
in tincture of iodine, dried, and then wetted
with water. In other cases it is necessary
to apply dilute sulphuric acid and solution
of iodine simultaneously. It is sometimes
difficult to bring out the blue reaction in
old cells ; various methods are had recourse
to for this purpose. In corky or other epi-
dermal tissues, the blue colour of cellulose
may be brought out by soaking the cells for
twenty-four hours or more in strong solution
of potash, washing it well, soaking in tinc-
ture of iodine, drying, and then wetting with
water. Old wood-cells undergo the same
change by boiling in nitric acid, instead of
treating with caustic potash, and then
adding the iodine, &c. as above. All the
solid structures of cell-membranes yield to
one or other of these means, and exhibit
the blue colour with iodine, which, if not
indicative of a composition of cellulose,
points to a substance intermediate between
this and starch, produced out of the cellu-
lose by the chemical action. The most
characteristic property of cellulose, how-
ever, is its solubility in ammoniuret of
copper (CELLULOSE.) The cells of Fungi
and many Lichens and Algee do not exhibit
the ordinary reactions of cellulose, becoming
brown instead of blue with iodine and sul-

CELL-CONTENTS.

[ 149 ]

CELLULARIID^E.

phuric acid, and they are moreover not
dissolved by ammoniuret of copper ; while
certain cell -walls of Lichens are coloured
blue by iodine alone, from the presence of
granulose. Cell-membranes and their mo-
difications are examined, of course, in
similar preparations to those mentioned as
displaying the forms &c. of cells.

Further information will be given in the
articles relating to the structures into the
composition of which the cells enter.

BIBL. — General. Henfrey-Masters, Bo-
tany ; Hold, Veget. Cell, tr. by Henfrey,
1853 ; Schacht, Pflanzenzelle, Berlin, 1852;
linger, An. u. Phys. Pftanzen, Vienna, 1855;
Meyen, Pflanzenphys. Phytotomie ; Morren,
Bull, de FAcad. de Bruxelles, v. No. 3;
Braun, Rejuv. (Ray Soc. 1853) ; Prin2:sheim,
Jahrb. wiss. Bot. 1858, i., ii. ; Mohl, Cellu-
lose, Bot. Zeit. v. (Scientific Memoirs, 2nd
ser. vol. i. 90) ; Bot. Zeit. xi. 753; Harting,
Mulder's Phys. CJiem. 1849 ; Bot. Zeit. v.
337; Kiitzing, Phil. Bot. 1852; Agardh,
Cell, veget. &c. 1852 ; Caspary, Streifung
d. Zellemoand, Bot. Zeit. xi. 801 ; Criiger,
Primitive Faser, Bot. Zeit. xii. 57, xiii.
p. 601 ; Dippel, Vegetal. Zellenbild. 1858 ;
Hofmeister, Pflanzenzelle, 1867; Karsten,
Ann. N. H. 1863 and 1864; Nageli, Mikr.
1877, 532 ; Sachs, Bot. 1874, 8. See also
PRIMORDIAL UTRICLE.

CELL-CONTENTS.— This term corre-
sponds, in regard to vegetables, to the word
endochrome as used by Thwaites, Ralfs, and
some of the Erench botanists. It refers
here most essentially to the protoplasm or
primordial utricle, as this is the part effec-
tive in development ; while the substances
imbedded in or lying in the cavity of this
are variable according to age, stage of deve-
lopment, &c. See PRIMORDIAL UTRICLE.

CELLA'RIA = SALICORNARIA.

CELLE'PORA, Fabr.— A genus of In-
fundibulate Polyzoa, of the suborder Chei-
lostomata, and family Celleporidse.

Distinguished by the massive, globose,
and incrusting, or erect and branched,
calcareous polypidom, and the irregularly
heaped vasiform cells, vertical to the com-
mon plane, with a beak on one or both sides,
furnished with an avicularium. Seven
British species.

C. pumicosa. Rough, porous, massive ;
cells suborbicular, the mouth round. Com-
mon.

C. vitrina. Incrusting ; cells ovoid, very
small, pearly, and irregularly arranged.

BIBL. Johnston, Brit. Zooph. 295; Gosse,

Mar. Zool. 17; Busk, Polyz. ii. 85; Paleont.
Soc. ( foss.} 1859 ; Hincks, Polyzoa, 398.

CELLEPOREL'L A, Gray.— A genus of
Infundibulate Polyzoa, of the suborder
Cheilostomata, and family Porinidse.

Two species.

BIBL. Hincks, Polyzoa, 413.

CELLEPO'RIDvE.— A family of Infun-
dibulate Polyzoa (Bryozoa), of the suborder
Cheilostomata.

Char. Those of the single genus Cel-
lepora.

CELLULAR TISSUE, OF ANIMALS.
See CONNECTIVE TISSUE.

CELLULAR TISSUE, OP PLANTS. See
TISSUES, Vegetable.

CELLULA'RIA, Pallas.— A genus of
Infundibulate Polyzoa (Bryozoa), of the
suborder Cheilostomata, and family Cellu-
lariidae.

Distinguished by the jointed, branched,
erect polypidom, with flat, linear branches ;
the contiguous cells in two or three rows,
perforated behind, and more than four
between two joints; and the absence of
avicularia and vibracula. One British
species :

C. Peachii ( Cellularia Peachii, var., John-
ston). Cells narrowed downwards, truncate
and somewhat rounded above ; usually a
small spine at the upper and outer an^le ;
three to five perforations behind ; orifice
oval, regular ; margin somewhat thickened,
minutely granular ; ovicell globular with a
tessellated surface. On stones &c. from
deep water.

C. ciliata (Johnston) = Bicellaria oil.; C.
avicularia=Bugula avic. ; C. ternata—Me-
nipea tern. ; C. scruposa = Scrupocellaria
scrup. ; C. reptans = Canda rept. ; C. Hoolteri
— Caberea Hook. ; C. neritina=Bugula ner. ;
C. plumosa= Bugnla plum.

BIBL. Busk, Mar. Polyz. 20 ; id. Ann.
Nat. H. 1851, vii. 82 : Hincks, Polyz. 33.

CELLULA'RIID^E.— A family of In-
fundibulate Polyzoa (Bryozoa), of the sub-
order Cheilostomata.

Distinguished by the branched, erect
polypidom, and the flat, linear branches,
with the cells in one plane. Genera :

Cellularia. Cells in two or three rows,
contiguous, perforated behind, more than
four between two joints ; no avicularia nor
vibracula.

Menipea. Cells oblong, narrowed down-
wards, not perforate ; one or two avicularia
below the orifice in front.

Scrupocellaria. Cells with a vibraculum

CELLULOSE,

[ 150 ]

CEMENTS.

behind, and a sessile avicularium at the
upper and outer angle ; orifice spinous.

Canda. Cells with a vibraoulum in a
notch on the outer side ; no avicularium at
the upper angle.

BIBL. That of the genera.

CEL'LULOSE.— The proximate princi-
ple of which the permanent cell-membranes
of plants are always composed; it occurs
also in some structures of certain animals,
as the mantle of the Tunicata, the skin of
the silkworm, the elytra of some insects, the
tegument of some Crustacea, &c. In plants,
its physical characters differ very much in
different cases ; sometimes it is exceedingly
soft, and at once acquires a blue colour
with iodine (amyloid?). Usually it be-
comes blue when soaked in tincture of
iodine, dried, and then wetted with water.
In other cases it is more dense, and does not
become coloured blue with iodine until after
treatment with sulphuric acid, when it be-
comes more or less bright blue (the ordinary
test for cellulose) . Occasionally this reaction
gives a purplish colour. In old, infiltrated,
or greatly consolidated cellulose structure,
this test gives only a yellow-brown colour ;
but boiling in nitric acid (for woody tissues)
or solution of potash (for epidermal tissues)
will generally bring the cellulose into a state
in which, if wetted with tincture of iodine,
dried, and then wetted with water, it turns
blue. The blue colour is produced in some
resisting kinds of cellulose by a solution of
iodine in chloride of zinc or by iodide of
zinc. (SCHULZE'S TEST.) Sulphuric acid
swells and dissolves cellulose ; solutions of
potash and nitric acid do not act so quickly,
especially the latter. But the best test for
ordinary cellulose is the ammoniuret of
copper, which quickly dissolves it. Care
must be taken in testing for cellulose with
iodine, that no extraneous matter lodges
on the preparation; fragments of cotton,
blotting-paper, &c., consisting of cellulose,
might give rise to error. Minute crystals
of iodine precipitated from the tincture will
give the object a bluish tint.

In the lunicata, the intercellular sub-
stance consists of the cellulose, not the
cells (Schacht).

BIBL. See AMYLOID and CELL-MEM-
BRANES. Schacht, Mull. Archiv, 1851 (Qu.
Mic. Jn. 1852, pp. 34 and 106) ; Huxley,
Qu. Mic. Jn. 1852, p. 22; Schmidt (Tay-
lor's Scient. Mem. v. p. 1); Kb'lliker and
Lowig, Ann. Sc. N. Zool. 1846, p. 193;
Virchow, Compt. Rend. 1853 (Ann. N. H.

xii. p. 482) ; Schweitzer, Chem. Gaz. xvi.
66, 336; Gmelin, Hcmdb. d. Chem. vii. 574 ;
Hancock, Linn. Proc. 1867.

CEMENTS.— These are used for closing
the cells in which microscopic objects are
placed for preservation ; also for fastening
pieces of glass to each other, to form cells,
&c. Those, the method of making which
we have not described, can be procured at
any oil-shop.

Asphalt-varnish consists of a solution of
asphalt (must be real) in boiling linseed-oil,
or oil of turpentine, or in a mixture of the
two ; it should be creamy.

Black Japan consists of asphalt, gum
anime, amber, linseed-oil, and oil of turpen-
tine.

Brunswick black consists of asphalt, dry-
ing linseed-oil, and oil of turpentine.

Asphalt dissolved in benzole.

Canada balsam : a. alone ; b. digested
with sufficient ether, benzole, or chloro-
form, to render it slightly more fluid.

Electrical cement : a. is made by melting
together 5 parts of rosin, 1 part of bees'-
wax, and 1 of red ochre, b. The addition
of 2 parts of Canada balsam renders this
cement much more strongly adhesive to

Gold-size may be prepared by boiling 25
parts of linseed-oil for three hours with 1
part of red lead and £ of a part of umber ;
then pour off Successive portions of a
finely powdered mixture of equal parts of
white lead and yellow ochre are then added
to the oil, being well rubbed and mixed with
it, until a tolerably thick liquid is formed ;
this must be once more thoroughly boiled.
It is also sold.

Dammara-resm, is often used, dissolved
in benzole ; a third of gold-size is an advan-
tage.

Gutta-percha cement is made by adding
15 parts of oil of turpentine to 1 part of
finely cut-up gutta percha, and dissolving
by the aid of a continued heat and stirring.
The solution is then strained through a cloth.
In the strained solution, 1 part of shell-lac is
then dissolved by heat and stirring. The
application of the heat is continued until a
drop of the solution let fall upon a cold sur-
face becomes nearly hard. It can be ren-
dered thinner by the addition of more oil of
turpentine.

Marine glue consists of caoutchouc and
shell-lac dissolved in coal-naphtha by the
aid of heat. It is sold by microscope-
makers and those who mount objects.

CEMENTS.

CEPHALOPODA.

Sealing-ioax varnish. Prepared by add-
ing enough spirit of wine to cover coarsely-
powdered sealing-wax; and digesting at a
gentle heat.

Shell-lac varnish. Prepared in the same
manner as sealing-wax varnish, shell-lac
being substituted for the sealing-wax. 20
drops of castor-oil to the ounce is an im-
provement.

White hard varnish consists of gum san-
darac dissolved in spirit of wine, and mixed
with turpentine varnish.

Bismuth-cement. Made by thickening a
solution of mastic in chloroform with sub-
nitrate of bismuth.

India-rubber and asphalt. Made with
India-rubber 30 grs., asphalt 4 oz., mineral
naphtha 10 oz. Dissolve the caoutchouc in
the naphtha, then add the asphalt, and heat
if necessary.

White lead mixed with drying linseed-
oil, and oil of turpentine (white paint).

Wheat-paste should have a few drops of
some volatile oil, or carbolic acid added to
it.

Gum-arabic dissolved in water, with a
small quantity of glycerine, and a few drops
of volatile oil.

Zinc-cement. This is made with oxide of
zinc, drying oil, Dammara-resin, and ben-
zoline.

French cement, is made by melting India-
rubber scraps in a covered iron pot. When
quite liquid, lime previously slaked by ex-
posure to the air and in fine powder, is
added in small quantities at a time. When
moderately thick, it is removed from the
fire, well beaten in a mortar, and moulded
in the hands until of the consistence of
putty. It is useful for mounting large mi-
croscopic preparations &c. A drawn-out
thread of this is pressed upon the top of the
cell j the object and liquid are then added,
and the cover pressed upon the cement,
beginning at one side, so that the super-
fluous liquid may escape.

A number of other cements, applicable to
various purposes, are described by Beale in
How to Work &c. p. 54. The method of
using these cements is treated of under
PRESERVATION.

The varnishes should be kept in wide-
mouthed capped bottles, or in bottles accu-
rately closed by a cork, in the under part of
which a camel's hair pencil is inserted.

A black colour may be imparted to any of
the varnishes, by mixing them with lamp-

black ; or any colour, by adding correspond-
ingly coloured sealing-wax.

They should all be old, or kept some time
before use.

CENAN'GIUM, Fries. — A genus of
Phacidiacei (Ascomycetous Fungi) grow-
ing upon dead twigs, bursting through the
bark in the form of little cups or hollow
papillae. Tulasne has recently made some
interesting observations upon this genus,
and shown that the plants present two or
even three kinds of reproductive bodies,
asci with spores, and also spermogonia and
pycnidia with spermatia and stylospores. In
C. Cerasi) Fr., the pycnidia are minute
tubular bodies upon the same stroma as the
young cupules or asciferous cups. They have
been described as species of SpJueria and as
imperfect cupules of C. Cerasi; but their
walls are lined with basidia, producing
short-stalked stylospores, which are linear
and flexuous, and very large, viz. about
1-500" long; they exhibit three transverse
septa. In this species the pycnidia are
found in groups, and sometimes become
confluent. In C. Fraxini, Tul. (PI. 26.
fig. 17), the pycnidia contain not only stylo-
spores at the base of the cavity, but around
the upper part are found spermatia seated
on branched articulated filaments. These
organs, however, are not regularly co-
existent, but occasionally occur alone in a
pycnidium; and sometimes the spermatia
occur even in the asciferous cupules. The
asci in the cupules of C. Franyulce line the
bottom of the cups, and are mixed with
paraphyses; each ascus or theca contains
four spores. Several other species are com-
mon in Britain.

BIBL. Berk. Hook. Br. Fl. ii. pt. 2, 211 ;
Ann. N. H. vi. 359, 2 ser. vii. 185; Tulasne,
Ann. So. Nat. 3 ser. xx. 133, pi. 16.

CENOMY'CE. See CLADONIA.

CENTROP'AGES, Kroyer.— A genus of
Copepodous Entomostraca.

C. typicus j brown ; North Sea.

C. hamatus ; marine.

BIBL. Brady, Copepoda (Ray Soc.}, i.
p. 64.

CEPHALOP'ODA.— An order of Mol-
lusca, containing the Nautilus, the Argonaut,
the Octopus, _ the Cuttle-fish (Sepia), &c.,
with the fossil Belemnites and Ammonites.
The cartilage of the cuttle-fish is noticed
under CARTILAGE ; the dorsal plate or se-
piostaire under SHELL.

The chromatophores, or cutaneous pig-

CEPHALOSIPHON.

[ 152 ]

CERATAULUS.

ment-cells, and the cutaneous connective
tissue are interesting structures.

CEPHALOS'IPHON.— A doubtful ge-
nus of Rotatoria.

C. limnias. On Ceratophyllum.
BIBL. Pritchard, In/us, p. 070 ; Hudson,
M. M. Jn. 1875, xiv. p. 105.

CEPHALOTHAM'NIUM, Stein. — A
genus of Flagellate Infusoria.

Char. Those of Anthophysa, but the
pedicle stiff, hyaline, and homogeneous;
filaments two.

C. ccespitosa. Pedicle short ; attached to
Cyclops. C. cuneatum, pedicle long ; also
on Cyclops.

BIBL. Kent, Inf. p. 272.
CEPHALOT'RICHUM, Fr.— A genus
of Dematiei (Hyphomycetous Fungi).

C. curium is an extremely minute plant
growing upon the leaves of Sedges ; with
scattered, short, brown, erect filaments,
bearing somewhat globular heads composed
of tufts of forked or ternate branches, with
one or two short acute branchlets, slightly
scabrous, bearing smooth spores.

BIBL. Berkeley, Ann. N. H. vi. p. 432,
pi. 12. fig. 13; Corda, Ic. Fung. i. pi. 5.
figs. 253-4.

CE'PHEUS, Koch.— A genus of Oribatea
(Acarina).

Char. Cephalothorax with lamellar ap-
pendages ; tectum attached to cephalotho-
rax by its base only ; claws 3, alike.
C. vulgaris. Common near Paris.
BIBL. Nicolet, Oribatea (Monograph) ;
Murray, EC. Entom. 221 ; Michael, Tr. Mic.
Soc. 1880, 177.

CERAM'BYX, Linn. — A genus of
Pseudotetramerous Longicorn Coleoptera.

C. (Astynomus) cfdilis (fig. 307). Found
on old timber.

CERAMIA'CE^E.— A family of Flori-
deous Algae. Rose-red or purple sea-weeds,
one freshwater, with a filiform frond, con-
sisting of an articulated, branching filament,
composed of a single string of cells, some-
times coated with a stratum of small cells.
Fructification: \.favellce; berry-like recep-
tacles, with a membranous coat, containing
numerous angular spores; 2. tetraspores,
attached to the ramuli or more or less im-
mersed in the substance of the branches,
scattered; 3. antheridia, produced in the
same situations as the spores. British
genera :

Ptilota. Frond compressed, inarticulate,
distichous, pectinate-pinnate. Favellcs pe-
dunculate, involucrate.

Microcladia. Frond filiform, inarticulate,
dichotomous. Favellcs sessile, involucrate.
Ceramium. Frond filiform, articulate,
dichotomous; the joints opaque. Favellce
sessile, mostly involucrate. Tetraspores
mostly immersed.

Spi/ridia. Frond filiform, inarticulate;
the branches clothed with minute setiform,
articulated ramelli. Favellcs pedunculate,
involucrate. Tetraspores sessile on the
ramelli.

Grijfithsia. Frond articulated, dichoto-
mous, or clothed with whorled, dichoto-
mous ramelli, rose-red. Favellcs involucrate,
sessile or pedunculate. Tetraspores sessile,
on whorled ramelli.

Wrangelia. Frond articulated, pinnate.
Favellcs terminal, involucrate, containing
tufts of pear-shaped spores. Tetraspores
sessile, scattered on the ramelli.

Seirospora. Frond articulated. Tetra-
spores arranged in terminal, moniliform
strings.

Cattithamnion. Frond, at least the
branches and ramuli, articulated, mostly
pinnate. Favellcs terminal or lateral, sessile,
without involucre (except
in C. Turneri). Tetraspores JTJO-. 114.
sessile or pedicellate, scat-
tered.

Chantransia. Fresh-
water ; fronds filamentous,
articulate, branched, cells
in single series ; favellcs in
terminal corymbs.

BIBL. Harvey, Man. Br.
Alga ; Cramer, Ceram.
1803; Sachs, Bot. p. 393.
See also the Genera.

CERA'MIUM, Roth.—
A genus of Ceramiacess Ceramium Des-
(Florideous Algae), contain- longchampsii.

ing a number of species, Fragment of a frond

mostly growing between

tide-marks, of which C. cih-

atum is noted as a beautiful

object under a low magnify- metera.

ing power. The tetraspores

are often only triple, and arranged tetrahe-

drally and not in a row (fig. 114).

BIBL. Harvey, Mar. Algcc, pi. 22 C;
Phyc. Br. pis. 139-41, &c.

CERATAU'LUS, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules binate or concatenate,
septate; valves turgid, suborbicular or
broadly ovoid, with 2 tubular processes al-
ternating with 2 spines. Marine and fossil.

and two empty

dia.

CERATIDIUM.

[ 153 ]

CERCOMONAS.

C. turgidus — Biddulphia turgida ; C.
Smithii = Eupodiscus radiatus ; C. Ice vis =
Biddulphia levis; C. thermalis.

BIBL. Ehrenberg, Ber^Berl. Ak. 1843,
270 ; Rabenhorst, Fl. Alg. i. 313.

CERATID'IUM. Ehr.— A genus of In-
fusoria, of the family Oxytrichina.

Char. Furnished with cilia, horns on the
fore part of the body, but neither hooks nor
styles.

One species, C. cuneatum. Dujardin con-
siders this to have been a mutilated Oxy-
tricha. The appearance of horns arises from
the anterior part of the body being deeply
notched.

BIBL. Ehr. In/us.; Dujardin, Inf. 421.

CERA'TIUM. —A genus of Isariacei (Hy-
phomycetous Fungi) containing a generally
diffused British plant, C. hydnoides, which
grows on rotten wood as a tuft of white
simple or slightly branched oblong processes,
which produce on their surface sterigmata
(spicules, Berk.\ each of which is sur-
mounted by a spore which easily falls off.
The whole plant readily collapses into a
mucilaginous mass. The cellular appear-
ance figured by Greville depends on the
collapsing of the processes.

BIBL. Berk. Hook. Br. Fl. ii. pt. 2. 329;
Grev. Crypt. FL pi. 168.

CERA'TIUM, Schrank.— A genus of
Cilio-flagellate Infusoria = Peridinia with
horns.

CERATOCLA'DIUM, Corda.— A genus
of Hyphomycetous Fungi ; consisting of a
single species, C. microspermum (fig. 349),
characterized by the erect, septate horny
threads, clothed with a pallid stratum
bearing simple sporophores (basidia),
terminated by a single staff-shaped
spore.

BIBL. Corda, Prachtjl. pi. 20.

CER'ATODON, Bridel. — A genus of
Pottiaceous Mosses.

C. purpureus, very common on banks and
walls, seta purple-red; C. cylindricus, seta
pale.

BIBL. Wilson, Bryolog. Br. 83 ; Berkeley,
Brit. Moss. 274.

CERATONE'IS, Ehr.— A genus of Dia-
tomacese.

Char. Frustules cymbiform, free, with a
more or less distinct central nodule, the
apices rostriform and produced.

Smith places the British species in other
genera, thus :

C. arcus=Eunotia arcus- C. closterium
= Nitzschia cl. ; C. fasciola = Pleurosigma

fasc. ; C. gracilis= Nitzschia tcenia ; C. Ion-
gissima — Nitzschia birostrata.

Rabenhorst admits C. arcus, C. amphioxys,
and C. toxon (Perty).

BIBL. Ehr. Ber. d. Berl. Ak. 1839, 1840
et seq. ; Kutz. BacilL and Sp. Alg. ; Smith,
Br. Diat. ; Rabenhorst, Fl. Alg. i. p. 76 j
Perty, Lebensf. p. 205.

CERATO''NIA, Linn.— A genus of Le-
guminosae (Flowering Plants). The pods
and seeds or beans of C. siliqua — the Carob-
or Locust-tree of Spain, are used for adul-
terating coffee. PI. 2. fig. 8, «, 6, repre-
sent the characteristic tissues of the pod ;
e and d, those of the bean.

CERATOP'TERIS, Brongniart.— A ge-
nus of Pterideae (Polypodiaceous Ferns).
Exotic. The inrolled margin of the leaf
simulates an indusium.

C. thalictroides ; tropics (figs. 226-7
thecae, 228-30 spores).

BIBL. Hook, Fil. Syn. p. 174.

CERCA'RIA, Miill.— These organisms
were formerly regarded as constituting a
genus of Infusoria, but are now known to
consist of the larvae or nurses of Trematoda,
as Distoma, &c.

The body is oblong,depressed, changeable ;
the mouth subterminal, armed or unarmed.
Acetabulum subcentral. Tail filiform, sim-
ple, attenuate at the apex, deciduous.

They are found parasitically on the body,
or within the intestines, liver, ovaries, &c.
of Mollusca (Lymntcus, Planorbis, &c.) ; and
may be obtained by wounding the body in
water.

C. furcata (PL 51. fig. 32). On Lymnaus
stagnaliSj in autumn ; length 1-12". C. he-
lids viviparce, in the liver of Pahidina vivi-
para. C. planorbis, in the ovaries of Pla-
norbis corneus and marginatus.

Diesing describes 12 " species." See
DISTOMA.

CERCO'MONAS, Duj.— A genus of Fla-
gellate Infusoria.

Char. Free, body rounded, discoidal or ob-
long, sometimes tuberculated, with a va-
riable posterior prolongation in the form of
a tail, which is longer or shorter and more
or less filiform (PL 30. figs. 22, 23).

Dujardin remarks that the only absolute
difference between the Cercomonads and
the Monads consists in the presence of the
posterior prolongation, which is formed by
the substance of the body becoming agglu-
tinated to the slide, and more or less drawn
out so as to form sometimes merely a tuber-
cle, at others an elongated tail, or a filament

CERCOMONAS.

[ 154 ] CERUMINOUS GLANDS.

almost as slender as the anterior filament
and susceptible of an oscillating motion;
also that he thinks he has frequently seen
Monads gradually pass into the state of
Cercomonads. See BODO.

Found in infusions, pool-waters, £c.

C. acuminata (PI. 30. fig. 22). C. crassi-
cauda (PI. 30. fig. 23). C. intestmalis, in
typhoid diarrhoea, cholera; other species,
many doubtful.

Dallinger and Drysdale describe in a
species of Cercomonas (C. typicus, Kent),
found in cod-macerations 2-3 months old, re-
production by transverse fission ; also by con-
jugation— the individuals becoming amoe-
boid, fusing together, and forming a smooth
cyst, from which myriads of almost imper-
ceptible germs are subsequently liberated.

BIBL. Duj. Infos. 287; Pritchard, Inf.

Fig. 115.

Magnified 20 diameters.

Perpendicular section of the meatus auditorius externus. a. Cerium;
b, rete mucosum ; c, epidermis ; d, ceruminous glands ; e, their ducts ;
/, their terminal orifices; g, hair- follicle ; h, sebaceous follicles; i, fatty
tissue.

497 ; Perty, Z. KennL 171 ; Kent, Inf. 2o8 ;
Dallinger and Diysdale, M. M. Jn. 1873,
x. 53, 245.

CEREUS. See CACTACEJE.
CERU'MEN.— The so-called 'wax' of
the ear.

Its morphological elements are : — 1. Hairs ;
these exhibit very beautifully the external
layer of epidermic scales. 2. Occasionally,
the Demodex folliculorum. 3. Numerous
epidermic scales, mostly compressed, shrunk,
or so altered as to resemble fibres, but re-
solvable into their original form by warm-
ing with solution of potash and the subse-
quent addition of water; by this treat-
ment they are frequently rendered brown,
purplish, or almost black. 4. Very nu-
merous cells, filled with pale fatty matter,
of a rounded or elongate, flattened, or irre-
gular form ; these are derived
from the sebaceous follicles.
5. Numerous free oil-globules
of the most varied sizes. 6.
Yellow or brown granules,
and aggregations of them,
mostly free, sometimes con-
tained in cells. 7. Various
elements derived from with-
out, as fibres of cotton, linen,
&c. The deafness of old per-
sons usually arises from an
accumulation of indurated
cerumen. See CEBUMINOUS
GLANDS.

CERU'MINOUS GLANDS.
— The glands which secrete
the ' wax ' of the ear. They
are situated in the tube of
the ear, or the meatus audi-
torius externus of anatomists.
They closely resemble the su-
doriparous ducts in appear-
ance, and exist only in the
cartilaginous portion of the
passage, where they are situ-
ated between the skin and the
cartilage, or the fibrous mass
which occupies its place.
Each consists of a simple
tube coiled at one end, so as
to form a gland (fig. 115 ef),
the other being continued in
the form of a duct (fig. 115 e)
to the surface of the skin,
upon which it opens; occa-
sionally, however, into the
upper part of the hair-follicle.
The glands consist of an ex-

CERVINIA.

[ 155 ]

CILETOGLENA.

ternal coat of connective tissue, with scat-
tered, somewhat spindle-shaped nuclei, and
very fine nuclear fibres ; a layer of smooth,
longitudinal, muscular fibres, consisting of
short fibre-cells with elongated nuclei ; and
an inner single layer of epithelium, com-
posed of polygonal cells, from 1-1800 to
1-1100" in diameter, with roundish nuclei.
These cells contain round or irregularly-
shaped yellowish-brown, granules, of very
various sizes, as also globules of oil. The
duct has a coat of connective tissue, and an
epithelial coat, consisting of several layers
of small nucleated cells, not containing fat
or pigment-granules.

CERVIN'IA, Norman. — A genus of
marine Copepodous Entomostraca.
C. Bradyi. Oban.

BIBL. Brady, Copepoda (Ray Soc.), i. 85.
CESTODISCUS, Grev.— Frustules disk-
shaped, circular or oval ; valves with radia-
ting granules, and a submarginal circle of ob-
tuse nrocesses unconnected by special radia-
ting lines of dots with the centre. 4 species.
BIBL. Greville, Mic. Trans. 1865, 48 j
1806, 123.

CE'TERACH, Willd.— A genus of Ferns,
usually arranged with the ASPLENIE.S:,
although there is only a rudimentary indu-
sium, the place of this being supplied by
scales. C. officinarum (Asplenium Cete-
racli), the native species, occurs chiefly in
limestone districts.

OETOCHTLUS.— A genus of Entomos-
traca (Crustacea), belonging to the order
Copepopa, and family Cetochilidee.

Distinguished by the two small styliform
appendages to the head ; the two-branched
inferior antenna, the branches nearly equal ;
the unbranched jaw-feet; the six-jointed
thorax, and four-jointed abdomen; and the
last pair of legs being formed like the rest.
Marine. C.septentrionalis] bright red; forms
part of the food of the whale and various
fishes; length 1-10".

BIBL. Baird,.Z?n'f..E'n£0m0*.p.233; Grob-
ben, Clauses Arb. 1880, 243, iii. (Jn. Mic.
Soc. 1881, i. 734).

CETRA'RIA, Ach.— A genus of Lichens
tribe CetrarieL

Char. Thallus bright brown, rigid, erect
or ascending, divided into lacinise, with
shining cortical layer. Apothecia dull or
"bright brown. Spermatia cylindrical.

3 British sp. : C. islandica,"ihe well-known
Iceland Moss ; C. Delisei ; and C. aculeata.
BIBL. Nylander, Syn. 298; Leighton
Lichen-Flora, 1879, 91.

CETRARIE'I. — A tribe of Lichens ;
family Lichenacei.

Char. Thallus compressed, fruticulose, or
membranously dilated ; apothecia marginal j
spores 8, small, colourless, simple.
Genera : Cetraria and Platysma.
CEUTHOS'PORA, Fr.— A genus of Me-
lancouiei (Stylosporous Fungi) closely re-
lated to Phoma, one common species of
which (C. phacidioides) grows on holly-
leaves ; another occurs on the Cherry-laurel
(C. Lauri). It is probable that these are
only forms belonging to some Ascomycetous
genus.

C. phacidioides, Grev. 3-5 cells in the
stroma, splitting into 3-5 plain short teeth.
C. Lauri, Sow. Unilocular, splitting into
3-4 acute teeth.

BIBL. Berk. Hook, Br. Fl ii. pt. 2. p. 283 j
Grev. Crypt. Fl. pis. 253, 254.

CELETO'CEROS, Ehr.— A genus of Dia-
tomaceas.

Char. Frustules concatenate; valves equal,
subcylindrical, with two processes, one on.
each side, which, in the young state, are
very short and tubular, forming very long
horns as the frustules become older ; horns
subsequently converted into very long, thin
and interwoven siliceous filaments. Marine
and fossil.

Somewhat allied to Biddulphia. Raben-
horst admits 18 species. C. didymus (PI. 50.
fig. 47). Some British.

BIBL. Ehrenb. Ber. d. Berl. Ak. 1844,
198; Kiitzing, Sp. Aly. 138; Brightwell,
Micr. Jn. vi. 155 ; Lauder, Mic. Tr. 1864,
75 ; Rabenhorst, Fl. Alg. i. 321.

CILETOCOC'CUS, Ktz.— A doubtful
genus of Algse.

Char. Filaments rigid, short, spiniform,
arising from a cellular substratum.

C. violaceus, radiate, green, becoming
violet on drying, on Rhizoclonium ; C. hyali-
nus, on Cladophora.

BIBL. Rabenhorst, Flor. Alg. ii. 199.
CH^ETODIS'CUS, Grev.— A genus of
DiatomaceaB.

Char. Frustules disk-shaped; valves cir-
cular or oval, with radiating dots and a
submarginal circle of obtuse processes un-
connected by means of special radiating
lines of dots with the centre.
4 speciee.

BIBL. Greville, Mic. Tr. 1865, p. 48;
1866, p. 123.

CH^ETOGLE'NA, Ehr.— A genus of In-
fusoria, of the family Peridinsea.

CJiar. Carapace hispid, or studded with

CH^TOMIUM.

[ 156 ] CH^ETOPHORACE^.

rigid spines ; no transverse furrow ; an eye-
spot present j organ of motion a flagellilbrni
filament.

C. Volvotina (PI. 30. fig. 24 a). Oval,
internal substance brownish-green ; eye-
spot red ; length 1-1 100". Aquatic. This
appears to be the same as Trachelomonas
Volvodna. See TRACHELOMONAS.

C. caudata. Oval, hispid, with a short
tail ; internal substance green ; eye-spot red ;
margin of carapace urceolate and toothed j
length 1-850" ; aquatic.

BIBL. Ehr. In/us. ; id. Ber. d. Berl Ak.
1840, 199 ; Dujardin, Infus. 239.

O&ETO'MltJM, Kunze.— A genus of
Perisporiacei (Ascomycetous Fungi), having
a filamentous mycelium bearing superficial
roundish or ovate conceptacles clothed with
hairs, finally opening above and containing
clavate asci with paraphyses ; sporidia sim-
ple, ovate. The asci in this genus are very
delicate and are readily absorbed, so that
frequently there is not a trace of them, and
the sporidia seem naked. British species :

C. datum, Kunze. Conceptacles sub-
ovate, black or brown, more or less crusta-
ceous ; sporidia apiculate at each end.
Greville, So. Crypt. Fl. pi. 230. On mould-
ering straw, old matting, &c. Very com-
mon.

C. chartarum, Ehr. Conceptacles sub-
globose, black, surrounded by a bright yel-
low spot ; sporidia roundish. On paper.

C. fflabrum, B. On damp straw.

BIBL. Hook. Br. Fl. ii. pt. 2. p. 328 ;
Kunze, Mycolog. Heft i. ; Fries, Syst. My-
col iii. p. 254, 255.

CH^E'TOMONAS, Ehr.— A genus of In-
fusoria, of the family Cyclidina.

Char. An oral vibratile organ (whether
a flagelliform filament or ring of cilia is
uncertain) ; movement of animal slow, but
leaping effected by means of non-vibratile
bristles situated upon the body.

In putrid animal and vegetable infusions ;
in dead bodies of other organisms — Clos-
teria, &c.

C. globulus (PI. 30. fig. 25 a). Nearly
spherical, ash-coloured, setae numerous ;
length 1-2700".

C. constricta (PI. 30. fig. 25 6). Oblong,
constricted in the middle, hyaline, setae two ;
length 1-5400".

BIBL. Ehr. Infm. p. 248.

CH^ETOMORPHA, Kiite.
spec. (Rabenhorst, Fl. Alg. iii. p. 327).

CHvETONO'TUS, Ehr.— A genus of mi-
croscopic aquatic animals, placed by Ehren-

berg among the Rotatoria (Rotifera), and
by Dujardiii with the Infusoria.

Ehrenberg places it in the family ICHTHY-
DINA. Dujardin gives the following cha-
racters :

Body oblong, convex, and furnished with
hairs or scales above ; flat and provided
with very minute vibratile cilia beneath ;
terminated in front by a rounded margin,
near which is a distinct mouth ; posteriorly
bifurcate or terminated by two caudiform
processes.

The three or four species are found in
fresh water, amongst aquatic plants. Their
structure requires further investigation.

Chcetonotus larus (PI. 31. fig. 24). Length
1-710 to 1-220".

Dujardin appends Ichthydium, Ehr., to
this genus.

BIBL. Ehr. Infus. 389 ; Duj. Inf. 568 ;
Mecznikow, Siel. § Koll. Zeitsch. 1865
(Qu.Mic.Jn. 1866,240).

CH^ETO'PHORA, Schrank.— A genus
of Chaetophoraceae (Confervoid Algae), cha-
racterized like Draparnaldia by setigerous
branched filaments, but differing from the
latter by the filaments being imbedded in a
gelatinous matrix. The Chcetophora are
found in fresh water, forming little green
protuberances on stones, sticks, &c., usually
bright green. The zoospores are formed
singly in the joints, and bear four cilia.
True fruit is figured by Berkeley in C. pisi-
formis, Gleanings of Br. Alg. pi. 1. fig. 1.

The membrane of the filaments is very de-
licate j and the zoospores appear sometimes
to escape by its solution. British species :

C. endiviafolia, Ag. Hassall, Alg. pi. 9.
fiars. 1, 2 ; Kiitz. Tab. Phyc. iii. pi. 21. tig. 3.
Ulva incras&ata, JEng. Bot. 967. Common
in streams.

C. tuberculosa, Hook. Hass. /. c. pi. 9.
7, 8 ; Kiitz. I. c. pis. 19 and 21. Rivularia
tuberculosa, Eng. Bot. 2366. Boggy pools.

C. elegans, Ag. Hass. /. c. pi. 9. 3, 4 ;
Kiitz. /. c. pi. 20. Stagnant pools ; com-
mon.

C. pisiformis, Ag. Hass. /. c. pi. 9. 5, 6 ;
Greville, Crypt, t. 150; Kiitz. I c. pi. 18;
Thuret, Ann. Sc.^Nat. 3 ser. xiv. pi. 19.
figs. 1-3. Subalpine lakes.

C. dilatata, Hass. /. c. pi. 13. fig. 2.

C. longceva, Carm. A doubtful species.
Hook. Br. Fl. ii. pt. 1.

Rabenhorst admits 10 species : Fl Ahr.
iii. 383.

BIBL. As above.

CH^ETOPHORA'CE^E.— A family of

CH^ETOPSIS.

[ 157 ]

CHALAZA,

Confervoid Algae, growing in sea or fresh
water, rarely terrestrial, invested with gela-
tine ; either filiform, or (a number of fila-
ments being connected together) expanded
into gelatinous, branched, definitely-formed
or shapeless masses or fronds. Filaments
jointed, furnished with bristle-like processes.
Fructification consisting of spores ; and four-
ciliated zoospores, formed out of the con-
tents of the articulations.

Synopsis of British Genera.
Draparnaldia. Filaments free, gelati-
nous, the primary nearly colourless, bearing
tufts of coloured ramuli at the joint; zoo-
spores formed singly in the joints of the
ramuli.

Ch&tophora. Filaments dichotomously
branched, aggregated into shapeless, in-
crusting or branched, gelatinous fronds, the
joints bearing bristle-like branches; zoo-
spores solitary in the articulations ; the
membranes of the filaments very fugacious.
Coleochcete. Frond disk-shaped or ir-
regularly expanded, adherent to leaves &c.
of aquatic plants under water, formed of
jointed dichotomous filaments radiating
from a centre, more or less conjoined late-
rally; the joints producing from the back a
slender truncate open tube, from which a
long bristle is exserted. Fructification :
spores and zoospores formed in the joints.

Ochlochcete. Frond discoid, appressed;
filaments cylindrical, radiating from a centre,
irregularly branched, consisting of a single
series of cells, each of which is commonly
prolonged above into an articulate bristle.

Foreign genus. See APHANOCHJETE,
Kiitz.

BIBL. See the genera.
CH^ETOP'SIS, Grey.— A genus of Mu-
cedines (Hyphomycetous Fungi) charac-
terized by erect jointed threads, whorled
below, above simple and flagelliform, bear-
ing cylindrical spores from the tips of the
branchlets. One species only is known, C.
Wauchii.

BIBL. Grev. Crypt. Fl pi. 236 ; Berkeley,
Br. Fung. 353 ; Cooke, Handbook, 614.

CBLETOSPI'RA, Lachmann.— A genus
of Infusoria, of the family Bursarina.

Char. Buccal spire supported on a narrow
band-like process, at the base of which is
the mouth.

C. Mulleri. Shell lageniform, horny. On
torn leaves oiLemna trisulca.

C. mucifola. Shell gelatinous. Among
Algae, fresh water.

BIBL. Ann. N. H. 1857, xix. pi. 9. figs. 6
and 7 ; Claparede and Lachmann, Infus. 216 ;
Kent, Infus. 601.

CHJETOSTRO 'MA, Corda. See VOLU-

TELLA.

CH^ETOTYPH'LA, Ehr.— A genus of
Infusoria, of the family Peridinaea.

Char. Carapace (siliceous ?) hispid or
covered with rigid hairs ; no transverse
furrow, no eye-spot.

C. armata (PI. 30. fig. 26 : a, side-view ;
6, posterior end view). Ovato-subglobose,
rounded at each end, hispid with short
setae, posteriorly a ring of dark prickles :
length 1-620".

C. aspera (PL 30. fig. 26 c). Oblong,
rounded at each end, hispid with short setae ;
posterior prickles scattered without order ;
length 1-550".

C. ? pyrites. Oblong cylindrical, ends
rounded; setae slender and elongate; no
posterior prickles ; length 1-1100", breadth
half the length. Fossil in flint. Ehreoberg
questions whether this is not a Xanthidium.
BIBL. Ehr. Infus. 250; Duj. Inf. 328.
CHAITOPH'ORUS, Koch.— A genus of
Aphidae.

Char. Antennas hirsute, 7-jointed; upper
wings with a doubly forked cubitus ; lower
with two oblique veins; abdomen studded
with tubercles tufted with bristles : dimor-
phous.

Several species ; occurring upon the wil-
low, poplar, birch, £c.

BIBL. Buckton, Aphides (Ray Soc.), ii.
120.

CHA'LAJRA. — A genus of Mucedines
(Hyphomycetous Fungi) ; characterized by
the erect jointed threads, which at their
slender apices break up into cylindrical
spores.

C. longipes has been found in this country.
BIBL. Sturm, D. Fl. 29, pi. 35 ; Saccardo,
Fasc. i. pis. 29-35.

CHALA'ZA (in plants).— The term ap-
plied to the base of the nucleus of ovules,

Fig. 116.

Section of an anatropous ovule : /, funiculus ; r,
raphe ; ch, chalaza ; p, external coat of testa ; s, inter-
nal coat or tegmen ; n, nucleus.

where the substance of the former is con-

CHALCIDID.E.

[ 158 ]

CHALCIDID.E.

tinuous with the coats, and where the vas-
cular cord derived from the placenta termi-
nates (fig. 116, ch).

CHALCID'ID^E.— A family of Entomo-
phagous Terebrant Hymenoptera, distin-
guished by the following characters : —

Head transverse, with the eves lateral
and the face usually bisulcate for the re-
ception of the base of the antennas (PI. 36.
fig. 8). Antennae short, frequently thick-
ened at the tips, sometimes branched, com-
posed of not more than thirteen joints,
and almost always geniculated at the ex-
tremity of the elongated first joint. Palpi
very short, sometimes branched. Thorax
ovate, with a distinct collar. Wings nearly
destitute of veins ; the anterior with a rather
strong subcostal vein running parallel to the
anterior margin for about half the length of
the wing, and terminating in a stigma, from
which a short vein is given off obliquely
towards the disk of the wing ; the posterior
sometimes veinless, sometimes with a short
subcostal vein. Legs moderate; hinder
thighs sometimes much thickened ; tarsi of
four or five joints. Abdomen generally com-
posed of seven segments in the males and of
six in the females, united to the thorax by
a peduncle of variable length ; ovipositor
usually concealed entirely in a cleft of the
lower surface of the abdomen, which ex-
tends nearly to the base (fig. 9), but some-
times exserted and very long. The struc-
ture of the ovipositor is the same as that of
the IchneumonidcR.

The larvae, like those of the rest of the
petiolated Hvmenoptera, are footless fleshy
grubs (fig. 10). Like the larvae of the Ichneu-
monidae, they usually live in the interior of
other insects ; but it is remarkable that those
of a few species attach themselves to the
skin of their victim, and in this position
feed upon its substance. The internal
feeders generally change to the pupa state
within the pupa of the insect attacked by
them ; a few, however, break through the
skin of the larva and attach themselves to it
or to neighbouring objects by a glutinous
secretion, or by a small silken cocoon. The
pupa? have the limbs more closely attached
to the body than in the other Hymenoptera;
and in those which have an elongated ovi-
positor, that organ is turned up over the
back. The pupae are at first whitish, but
afterwards become brown or black ; they
are usually naked (fig. 11).

The family Chalcididae includes an im-
mense number of parasitic Hymenoptera,

the majority of which are of extremely mi-
nute size, and adorned with the most bril-
liant metallic colours. This circumstance,
coupled with the delicacy of their form,
renders many of the species most beautiful
objects; and considering their interesting
habits, they certainly do not deserve the
almost total neglect which they have met
with. The largest species belong to the
genus Leucopsis ; but none of these greatly
exceed half an inch in length, and they are
not found further north than the South
of Europe. The thickened hinder thighs
which occur in manjr species of this fa-
mily, do not always indicate that the in-
sects possessing them are endowed with
saltatorial powers ; on the other hand, many
species which are destitute of thickened
thighs leap well ; and according to West-
wood's observations, this is especially the
case with those in which the intermediate
tibiae are furnished with a large spine at
the extremity (Encyrtut, PI. 36. fig. 12).

The perfect insects may be met with in
abundance during the summer and autumn
upon the leaves of trees and plants. They
may be taken either by sweeping the herb-
age with a net, or by beating trees or hedges
over a broad net or umbrella.

The sexes are often distinguished in this
family by remarkable external characters,
especially in the structure of the antennae.
These, in the males of many species, are
beautifully branched, in consequence of the
joints giving off processes from their sides ;
in Eulophus (fig. 13) we usually find three
branches ; and in some foreign genera re-
corded by Westwood the number is in-
creased to five, seven, and even nine. A
few species have the wings rudimentary or
entirely wanting ; and it is remarkable that
in some cases the male only is deprived of
wings, the female being well furnished with
these organs.

The Chalcididae are parasitic upon insects
of nearly all orders, and deposit their eggs
in them in all stages of their growth. Some
of the minute species even find sufficient
nourishment in the eggs of other insects ;
amongst these we may mention Pteromalus
ovulorum as a common species, which has
been reared from the eggs of Lepidopterous
insects. From a single egg of this descrip-
tion, Fonscolornbe obtained five or six indi-
viduals of a minute species, described by
him under the name of Pteromalus atomos.
Westwood also mentions the occurrence of
two species of this family in the egg-cases

CHALCIDID^:.

C

of species of Mantis from Brazil and the Isle
of France j and Sells has recorded the oc-
currence of no less than ninety-four speci-
mens of a small Pteromalus in a single egg-
case of a Blatta.

Other minute species deposit their eggs
in the bodies of Aphides ; and their larvse
find a sufficient supply of nourishment even
in such small insects as these. Some,
especially those forming the genus Cocco-
phagus of Westwood, attack the Coccidce,
of which they destroy great numbers.

Other species, including most of the larger
forms, live parasitically in the cells of the
solitary Bees and Wasps. Amongst these
we may notice the singular genus Mono-
dontomerus, one species of which, first
discovered by Audouiu, and described by
Newport in the ' Linnean Transactions/ is
found in the nests of Odynerus, Anthophora,
and Osmia. The male of this remarkable
insect has only rudimentary wings, so that
it is unable to quit the cell of the Bee or
Wasp in which it passed its earlier stages,
whilst the female, being well provided with
wings, can fly about, after impregnation, to
seek other nests in which to deposit her eggs.
The species which are furnished with long
ovipositors belong chiefly to the genus Cal-
limome (fig. 14, C. cynipis) ; they deposit
their eggs hi different kinds of galls, the
vegetable excrescences caused by the punc-
tures of various other insects upon plants.
The larv8B of these gallicolous Chacididae
devour the rightful occupant of the gall.

The instinct which prompts these insects
to deposit their eggs in the larvae of these
gall-producing insects, is scarcely so asto-
nishing as that by which others are impelled
to insert theirs into the bodies of other para-
sitic insects, whilst still enclosed within
the tissues of their victim. Some of these,
such as Clirysolampus siispensus and Coruna
clavata, attack the Iarva3 of the Aphidii,
minute Ichneumons which infest the bodies
of Aphides ; and De Filippi has recorded
the occurrence of the larvse of one species
within a small Dipterous larva which itself
lives in the egg of Ehynchites Betuleti in
the vineyards near Turin ^Ann. N. H. 1852,
ix. 461). De Filippi is inclined to regard
the phenomena observed by him as an in-
stance of alternation of general ions; but
they evidently constitute an example of
double parasitism.

BIBL. Westwood, Introd. ii. & Zod. Jn. ;
Spinola, Ann. Museum, xvii. 138-152 ; Nees
von Esenbeck, Hynenopt. Ichneum. Mon.

) ] CHALK.

ii. ; Boyer de Fonscolombe, Mon. Chalc.
Gallo-Proi'incice, Ann. Sci. Nat. xxvi. ;
Walker, Mon. Chalcid. ; Dalman and Bohe-
rnan in Kongl. Vet. Akad. Handlingar ;
Walker, Entom. Mag. and Ann. N. H. ;
Guerin's Mag. de Zool., Ent. Mag. &c., and
Haliday, Entom. Mag.

CHA'LIMUS, Burm. — A genus of Crus-
tacea, of the order Siphonostoma, and fa-
mily Caligidse.

Char. Fourth pair of legs slender, of only
one branch, and serving for walking ; frontal
plate with a long and slender prehensile
appendage arising from the middle of its
anterior surface.

C. scombri. Found upon the mackerel,
and upon species of Caligus, of which it has
been supposed to be the young; length
about 1-6".

BIBL. Burmeister, N.A.Acad. N. C. Bonn,
xvii. ; Baird, Brit. Entomostr. p. 278.

CHALK. — An earthy form of carbonate
of lime, constituting strata of great thick-
ness in England and several parts of Europe,
&c. The application of the microscope to
the examination of chalk brought to light
the interesting fact that this substance has
not had its origin in chemical precipitation,
since it contains abundance of the inorganic
remains of marine animals, and a few plants,
perhaps doubtful.

Many of these relics are not microscopic,
as those of Fishes and Reptiles, the shells of
Malacostracous Crustacea, Mollusca, Echi-
nodermata, the polypidoms of Zoophytes,
&c. ; hence their consideration does not
come within our province : yet it must be
remembered that their microscopic structure
is characteristic, so that the class, order, or
even the more minute division of the ani-
mal kingdom to which they belong may be
discovered. See BONE and SHELL.

The chief microscopic constituents of the
calcareous formations examined by Ehren-
berg, viz. chalk, and nummulitic and other
compact limestones, w^ere found to be
shells of Foraminifera, spicules of sponges,
and peculiar bcdies called crystalloids; and
several siliceo-calcareous earths he found
to be wholly composed of spicules, Diato-
maceee, Polycystina, and Foraminifera.

The Foraminifera found by Ehrenberg
in the Graveeend chalk were: — Cristellaria
cidtrata, Globigerina cretacca, Heterosto-
mella atuleata and tumens, Nodosaria ovi-
eida, Planorbidina ammonoides, Polymor-
phina Thouini, Pidvimdina Micheliniana,
Textularia agglutinans, gibbosa, globidosa.

CHALK.

[ 160 ]

CHAM^ESIPHON.

striata, and subangnlata, Vagimdina Icevigata
and longa, Verneuilina spinulosa, and Vul-
vulina pennatida. D'Orbigny enumerated
22 species from the English chalk, including
some of the above ; many others have also
been found.

The genera and subgenera in which they
are grouped are — Bolivina, BUUMINA, CAL-
CARINA, Cristellaria, Dentalina, Flabellina,
Frondicularia, Gaudnjina, GLOBIGERINA,
Haplophragmium,Heterostomella,Lingulina,
LAGENA, LITUOLA, Margimdina, MILIOLA,
Nodosaria, NODOSARINA, Planularia, Pla-
nulina, PLANORBULINA, POLYMORPHINA,
PULVINULINA, Quinquelocidina, Ramnlina,
ROTALIA, Sagrina, SPH^EROIDINA, TEX-
TULARIA, TINOPORUS, Tritaxitt, TROCHAM-
MINA, Truncatulina, VALVULINA, Verncui-
lina, Virgulina, and Webbina.

Ehrenberg found two Diatomaceae in the
English chalk, viz. Fragilaria capucina (F.
rhabdosoma), and Fr. pinnata, Ehr. (=F.
mutabilis, Sm.). Some other Diatomacese
referred by Ehrenberg to the chalk, belong
to foreign chalk and to totally different beds.

The material of chalk comprises very
minute, numerous, and remarkable bodies,
called crvstalloids and morph elites byEhren-
berg (PI. 25. fig. 15). They are elliptical
or rounded, and flattened, from 1-10,000 to
1-2500" in length, the most numerous per-
haps 1-3000"; some of them consist of a
simple ring (a) ; in others this is marked
with pretty regular transverse lines, so as to
make it appear jointed (b) ; in others, again,
there is a thinner central portion, often ex-
hibiting one or more granules (c). Ehren-
berg regarded these as arising from the dis-
integration of the microscopic organisms
forming the chalk into much more minute
calcareous particles, and their reunion into
regular elliptical j>lates or disks by a pecu-
liar process, differing essentially from, and
coarser than that of crystallization, but
comparable with it, — one probably preceding
all slow crystalline formation, and causing,
but not alone, the granular state of solid
inorganic matter. These microscopic bodies
have of late years been regarded as the
agglomerated or separate plates of very
simple protozoan organisms by Huxley,
Wallich, and Sorby. By Carter they are
believed to belong to an Alga (Cocco-
LITHS).

The best method of examining chalk for
minute Foraminifera is this : place a drop
of water upon a glass slide, and put into it
as much finely scraped chalk as will cover

the point of a pen-knife; then diffuse it
through the water, and set it aside for a few
seconds. Next remove the finest particles
which are suspended in the water, together
with most of the water, and allow the re-
mainder to become perfectly dry. Moisten
this remainder with oil of turpentine, nnd
warm it over a spirit-lamp ; then add Ca-
nada balsam, and digest it upon the brass
table (!NTR. xxviii). but without its froth-
ing. ' A preparation thus made seldom fails ;
and when magnified 300 diameters, the mass
is seen to be chiefly composed of minute
well-preserved organisms. As thus pre-
pared, the cells of the Foraminifera first
appear black, with a white central spot
(PL 24. fig. 3), which is caused by air-
bubbles contained within the cells/ The
balsam gradually penetrates into the cells,
the black rings of the air-bubbles disappear,
and the minute, frequently very circuit
cells of the Foraminifera become visible.
See FLINT, and FORAMINIFERA.

The crystalloids are best examined in
common whiting, or powdered chalk, which
has been shaken with water and set aside.
A very minute quantity removed with a
dipping tube will exhibit them.

BIBL. The various works on geology, as
those of Lyell and Ansted ; Mantell, Won-
ders, Medals of Creation, and Ann. N. H.
1845, xvi. p. 73 ; Bowerbank, Geol. Tr. 2s.
vi. ; Ehrenberg, Abh. d. Berlin. Ak. 1838
(Ann. N. H. 1841, vii.), and Abh. d. Scrl
Ak. 1840 (Taylor's Sc. Mem. iii.), and Mi-
krogeologie, 1854 ; Parker and Jones's Ehr.
resume, Ann. N. H. 1872; Williamson,
Manchester Lit. Phil. Soc. viii. 1847 ; Mor-
ris, Cat. Br. Fossils, 1854 j D'Orbigny,
Mem. Soc. Geol. d. France, iv. (Abs., Ann.
N. H. 1841, vii. p. 390) ; Zirkel, Mineral i<>n
#c.,1873, 303 j Dixon's Sussex, 2 ed., 1878,
123 & 283.

CHALK-STONES. This term is vul-
garly applied to the white concretions
formed around the joints in chronic gout,
or, as it is sometimes called, rheumatic gout.
They consist of very minute needles of urate
of soda (PI. 12. fig-. 12 b).

CHAIkLENE'MA, Kiitz. — A supposed
genus of Leptotricheous Algae, consisting of
dusky-coloured jointed filaments, forming
flocks in various syrups. Doubtless the my-
celia of some Fungi, such as PENICILLIUM.

BIBL. Kutzing, Sp. Alg. 158.

CHAM^E'SIPHON, Braun.— A genus of
Oscillatoriaceee (Confervoid Algae).

Char. Trichomata erect, seruginous or

CHANTRANSIA.

CHARACEJE.

violet, parasitic, sheathed, articulate ; ter-
minal joints forming1 rounded gonidia. Four
species.

C. confer vicola (PL 3. fig. 6). On Calo-
thrix, Vaucheria, &c,

BIBL. Rabenhorst, Fl. Alg. ii. 148 (figs.).

CHANTRAN'SIA, Fries. — A genus
of Cerarniaceae (Florideous Algae).

Species numerous, purple, violet, or ferru-
ginous. Found on stones, submerged mosses,
and wood. Antheridia subglobose, terminal,
tetraspores rare.

BIBL. Rabenhorst, Fl. Alg. iii. 401;
Pringsheim, Beit. z. Morph. d. Meeres-
Algen ; Hassall, Alg. 75.

OHA'RA, L. See CHAHACEJE.

CHARA'CE^E.— A family of plants ge-
nerally classed among the Algae, but which,
from the character of their reproductive
organs, perhaps demand a more elevated
position. They may be placed on the boun-
dary between the Algae and the Hepaticae.
They are remarkable for their well-known
' circulation/ first discovered by Corti. The
Characese are aquatic plants, of filamentous
structure, exhibiting elongated axes fur-
nished at intervals with whorls of branches
(fig. 117) ; these are sometimes regarded as
leaves. In some species this axis is a
simple tube (fig. 124), sometimes a tube
with a cortical layer of smaller tubes sur-
rounding it (figs. 118, 119). Some authors
have divided the species, on this and some
other grounds, into two genera, Nitella
(simple tubes) andC%anz (corticated tubes) ;
but according to Al. Braun, who has de-
voted great attention to this family, the
characters will not hold. The mode of
ramification of the simple tubes is seen in
figs. 124 & 125 ; that of the compound axes
is fundamentally the same, but other cells
arise from the branch cells at the articula-
tions, one above and one below each branch
(C. crinita). Those on the upper side of
the branches grow up over the central axis
to meet those descending from the under
side of the branches of the whorl next
above, the ends becoming intercalated about
the middle of the internode : in this course
of growth, cell-division takes place, and the
primary corticaftubes are not only made up
of many lengths in each internode, but each
is perpendicularly divided into two, one
large and one smaller tube (C. vulgaris), or
produces a secondary tube on each side (C.
aspera) ; the primary tubes stand out as ribs
from the surface. These cortical tubes de-
scribe a spiral course around the internode.

Fig. 117.

Fig. 118.

Fig. 120.

Fig. 119.

Fig. 117. Chara -vnlgaris. Natural size.
Fig. 118. Fragment of stem, magnified 15 diam., show-
ing the cortical tubes.

Fig. 119. A section of ditto, magnified 30 diam.
Fig. 120. Branch with nucule and globule, 10 d'nm.

Filamentous radical cells are also produced
from the whorls. The cells of the main
axis and its branches, and the primary cor-
tical cells, are those in which the circula-
tion of the contents may be seen best. The
cell- wall is lined by a close layer, like a

CHARACE^.

[ 162 ]

CIIARACE^E.

pavement, of chlorophyll-globules imbedded
in colourless protoplasm, arranged in a some-
what spiral order ; within them lies a thick
layer of semi gelatinous consistence (the
circulating protoplasm) ; and the centre is
filled up with a watery liquid. The circula-
tion in the ordinary cells consists in the
movement of the gelatinous protoplasmic
sac, as one mass, slowly up one side of the
cell, across the ends, and down the other
side, — not perpendicularly, however, but in
an oblique or spiral course, as indicated in
fig. 125. The fluid in the centre does not
circulate, but contains vesicles, granules, or
other bodies floating in it, which are free,
and when resting upon the protoplasmic
sac, are carried along by it and up the side
of the cell, until they fall down again by
gravitation. The young cells from which
the fruits are developed exhibit a circula-
tion of green vesicles ; the cortical filaments
have acirculating primordial utricle without
chlorophyll- globules.

The circulation is obscured in many Chares
by the existence of an incrustation of the
cell-wall by carbonate of lime, often found
in rhomboidal crystals. In C. (Nitella)
translucens, Jlexilis, and other species, this
does not exist ; and these species without
cortical tubes exhibit the phenomenon more
clearly than the others. Those species,
however, which are subject to incrustation
have comparatively little about the tips of
the shoots ; and if they are kept growing
for some time in a jar of water pretty free
from lime, new shoots maybe obtained very
suitable for examination. When we care-
fully examine the conical terminal cell of a
shoot, we find the following characters : —
The cell-membrane is distinctly laminated,
and thickened at the conical apex of the
cell ; when sulphuric acid and iodine are
applied, the cell-wall exhibits a thick in-
ternal layer of a blue colour, indicating its
composition of cellulose, while a thin layer
extending all over the outside becomes
bright yellow, and thus presents a resem-
blance to the cuticular layer of the higher
plants. The cell-wall is lined by a thin
layer of protoplasm, in which are imbedded
a vast number of chlorophyll-globules,
closely set and arranged spirally, as above
stated ; a clear line extends obliquely up in
this layer, bare of chlorophyll. The chloro-
phyll-globules have much the appearance
of vesicles here, and contain starch- cor-
puscles, which cause the whole layer to
turn blue with iodine. (See CHLOBO-

Fig. 121.

Fig. 124.

Fig. 121. A globule, magnified 50 diam., showing the
triangular valves.

Fig. 122. A globule cut in half, to show the oblong
cells and the septate filaments in the centre, 50 diam.

Fig. 123. Portion of a septate filament, 200 diam. ;
with two biciliated spermatozoids, 400 diam.

Fig. 124. Chara translucens, showing its simple tubes
and nucules grouped in threes under the terminal
globule.

Fig. 125. Diagram representing the course of the cir-
culation in the main tube and branches of Chara.

PHYLL.) Within this motionless layer is
found the thick rotating layer of protoplasm,
in which again are imbedded numerous
starch and chlorophyll-globules, a vast num-
ber of minute granules, and a number of
globular bodies of larger size, 1-1500", ac-
cording to Goppert and Cohn covered with
rigid cilia. The internal boundary of this

CHARACE^E.

[ 163 ]

CHEESE-MITE.

layer is wavy and irregular ; and thus its
rotation carries along-, to a certain extent,
the watery juice filling up the centre of the
cell, in which lie numerous transparent pro-
toplasm-vesicles, ciliated bodies, and gra-
nular matters.

The fructification of Chara is very curious,
and its homologies are not yet satisfactorily
made out. Upon the branches are found
bodies of two kinds, either on the same or
on different branches, or on different plants ;
called the globule and the nucule. The glo-
bule (figs. 120, 121) or antheridium is a
spherical body, of a red or orange-colour
when ripe, presenting a transparent thickish
outer coat, enclosing an inner wall of curi-
ous construction. This is composed of
eight triangular plates, each composed of a
number of long wedge-shaped cells radiating
from a central cell. The plates have dentate
margins, by which they fit into one another
(fig. 121). The cells contain a red colour-
ing-matter. In the centre of each plate,
inside, rises an oblong cell running in to-
ward the centre of the globule, where it
meets its fellows from the other plates, and
they are united by a little collection of sphe-
rical cells ; a ninth cell, of similar form but
larger size, comes to j oin these in the centre,
it being the pedicle of the globule, arising
from the branch upon which it is seated,
and entering the globule between the lower
four valves. At the point where these nine
cells meet in the centre, a number of long
septate filaments arise (fig. 122). These are
composed, when mature, of a large number
of cells placed end to end (figs. 122 & 123),
each of which finally discharges a ciliated
spiral filament (spermatozoid), which swims
actively in the water. The globule bursts,
by the separation of its triangular valves,
when mature ; and it is after this that the
spermatozoids are emitted. The form of
these spermatozoids is very like that of those
found in the Mosses, and different from what
is seen in the Ferns, Lycopodiacese, &c.
(PI. 40. figs. 31-34).

The nucule or carpogon of the Chara
(figs. 120 & 124) forms an oval body coated
by five cells, wound spirally around a central
tough sac; the five cells terminating above
in five or ten smaller cells, which project like
teeth from the summit, forming a kind of
crown. The cells of the crown separate from
each other at a particular period, leaving a
canal leading down to the central cell, which
contains protoplasm, oil, and starch- glo-
bules. Ultimately the nucule falls off, forms

a resting-spore, which germinates, and be-
comes developed into a new plant. The
germinating spore does not, however, di-
rectly give origin to the young plant ; but,
as in the higher Cryptogamia, a prothallus
is first formed, and upon this, the first
branches of the plant arise by ordinary
gemmation. The prothallus consists of a
single row of cells, forming a filament. This
is not produced, however, in Nitella.

The Chara also multiply by gemmas,
produced at the articulations of the stem ;
of which there are three modifications.

Carter has published some interesting
observations on the development of the root-
cells of Chara j also an account of the ab-
normal products which are sometimes found
in decaying cells.

BIBL. Corti, Osserv. sutta Circulazione^
1774 ; Amici, Mem. d. Societa t£o&cma,1818;
Ann. d. Sc. N. 1824 ; Dutrochet, Ann. d. Sc.
Nat. ser. 2. x. 349; Meyen, Pflanzen-phys.
ii. 206 ; Varley, Tr. Soc. Arts, xlix. 1833 ;
Micr. Tr. ii. 93, 1849 ; Slack, Tr. Soc. Arts,
xlix. ; Thuret, Ann. d. Sc. Nat. 2 ser. xiv.
65, 3 se*r. xvi. 18 ; Treviranus, Phys. d.
Gewdchse, \. 1839 ; Kiitzing, Phyc. gen. 313 ;
C. Miiller, Bot. Zeit. 1845 (Ann. N. H. xvii.
254) ; Goppert and Cohn, Bot. Zeit. vii. 665,
1849 ; Braun, Ber. Berl. Ak. 1852-3 (Ann.
N. H. 2 ser. xii. 297) ; Carter, Ann. N. H.
2 ser. xvi. 1, xix. 13 ; Pringsheim, Jahrb.
1864; Berk. Suppl. Eng. Bot. t. 2762 ;
Nageli, Beit. ii. 1860 ; De Bary, Monatsb.
Berl. Ak. 1871 ; Sachs, Bot. 295.

CHARA'CIUM, Braun.— A genus of
Confervoid unicellular Algae, of doubtful
position ; reproduction by repeated binary
division of the endochrome. Allied to Hy-
drocytium. Adherent to larger submerged
Algae. Perhaps only male spores of CEdo-
gonium and allied genera.

Ra,benhorst describes 13 species.

C. Sieboldii (PI. 5. fig. 2). On filiform
Algae and freshwater mosses.

BIBL. Rabenhorst, Fl. Alg. iii. 82; Braun,
Alg. Umcell. Gen. nova, 1855.

CHASMATOS'TOMA, Engelmann.— A
genus of Holotrichous Infusoria.

Char. Free, ovate or reniform j cilia long,
matted ; mouth near the centre of the flat-
tened ventral surface, enclosing a minute
undulating membrane.

C. reniforme. Fresh water ; length jl ff".

BIBL. Engelmann, Zeitsch. wiss. Zool.
1862, ii. ; Kent, Inf. 540.

CHEESE-MITE. See ACARUS DOMES-

TICUS.

CHEESE-MOULD.

[ 164 ]

CHELIFER.

CHEESE-MOULD. See ASPERGILLUS.

CHEILAN'THES, Sw. — A genus of
Pterideae (Polypodiaceous Ferns), nearly
related to Adiantum. The marginal lobed
indusium is very narrow ; some species have
the under surface of the leaves mealy, from
the presence of microscopic hairs.

A large genus ; tropical.

BIBL. Hooker, Syn. Fil. 131.

CHEILO'SCYPHUS, Corda.— A genus
of Jungermanniese (Hepaticae), founded
upon Jungermannia polyanthus, L., which is
not unfrequent in wet places.

BIBL. Hooker, Brit. Jungerm. pi. 62 ;
Corda, in Sturm, Deutschl. Fl. ii. 19, 20,
p. 35, pi. 9.

CHEILOSTO'MATA. — A suborder of
Infundibulate Polyzoa (marine).

Char. Orifice of cell filled with a thin
membranous or calcareous plate, with a
curved mouth, furnished with a moveable
lip.

It is divided into two sections, containing
numerous families and genera.

Tribe 1. Articulata. Polyzoarium jointed.

SALIC ORNARIID^. Polyzoarium erect,
cylindrical, dichotomously branched; cells
arranged on all sides.

CELLARIID^:.

CELLULARIIDJE. Polyzoarium erect,
branches flat, linear, cells in the same
plane.

Tribe 2. Inarticulata. Polyzoarium un-
jointed.

EUCRATIIDJE (Scrupariidse). Cells in one
row. AETEIDJE.

GEMELLARIID.^. Cells in pairs opposite.

CABEREID.E. Branches narrow ; cells in
two or more rows, with whips or sessile
birds' heads at the back.

BICELLARIIDJE. As the last, but whips
absent, and birds' heads stalked and jointed.

FLUSTRID.E. Zoarium expanded, folia-
ceous, and flexible.

MEMBRANIPORID^E. Expanded, incrus-
ting, stony ; cells horizontal, quincuncial.
MICROPORID^:.

CELLEPORID^E. Massive, globose, in-
crusting, or erect, stony; cells vertical to
the common plane, irregularly heaped toge-
ther.

Esc H ARID IE. Expanded and leafy, or
branching, stony ; cells in the same plane,
quincuncial.

CRIBRILINID^:, MICROPORELLIDJE,
MYRIOZOIDJE.

PORINIDJE. Polyzoarium incrusting, or
erect and branched ; cells with a raised
tubular or subtubular orifice, and frequently
a special pore on the front walls.

BIBL. Johnston, Br. Zooph. ; Busk, Cat.
Mar. Polyz. (Brit. Mus.) ; Gosse, Mar. Zool.
i. ; Hincks, Polyzoa, 1.

CHEIROCEPH'ALUS. See BRANCHI-
PUS.

CHEIROS'PORA, Fries.— A genus of
Melanconiei (Stylosporous Fungi), growing
upon the twigs of the beech. The myce-
lium spreads under the epidermis, and bursts
through in rounded or irregular, conical,
black pustules, 1-20'' in diameter, which are
composed of a large number of fine filaments,
unequal in length, and waved, each termi-
nating in a bunch of spores. The heads are
formed of chains of spores like a Penicillium,
when young, but crowded together more
densely as they become more fully developed
into a globular or oval head, about 1-7(JO";
the spores about 1-4000". This genus cor-
responds to Stilbospora, Montague, J\li/ri<>-
cephalum, De Notaris, and, apparently,
Hyperomyxa, Corda ; but the latter is said
to have a mucous vesicle enclosing the
head.

C. botryospora, Fr. On dead beech twigs,
Berk, and Broome, Ann. N. H. 2 ser. v.
455. Freseuius finds a variety on the horn-
beam.

BIBL. Cheirospora, Fries, Sttmma Veget.
508 ; Stilbospora, Fries, Syst. Mycolog. iii.
448 ; Montagne, Ann. Sc. Nat. 2 se*r. vi.
338, pi. 18. fig. 5; Hyperomyxa, Corda,
Ic. Fung. iii. fig. 78 ; Montagne, Ann. Sc.
Nat. 2 ser. xx. 378; Myriocephalum, De
Notaris, Mem. Accad. Torino, ser. 2. vii. ;
Fresenius. Mukoloqie, 39, pi. 5. fig's. 1-9
(2tesHeft). *

CHELIDO'NIUM, L.— A genus of Papa-
veraceous plants, remarkable for the yellow
juice contained in the laticiferous canals.
See LATEX.

CHE^LIFER, Leach.— A genus of Pseu-
doscorpioues (Arachnid a).

Char. Cephalothorax with a transverse
furrow ; eyes 2 ; no tail.

C. cancroides (PL 53. fig. 12). Brown,
palpi stout ; length £"• In old books, her-
baria, etc., and shady places.

C. muscorum. Palpi weaker ; abdomen
with a small appendage at the last joint ;
reddish.

Many other species.

BIBL. Gervais (Walckenaer), Ins. Ant
77 ; Murray, EC. Ent. 34.

CHEMICAL REACTIONS. [ 1C5 ]

CHILODON.

CHEMICAL REACTIONS. —INTRO-
DUCTION, p. xlii.

CHEMISTRY. — The following works
may be found useful for study or reference
in regard to chemical subjects: — Stockardt,
Exper. Chem. ; Grnelin, Handbueh ; Rose,
Anal. Chem. ; Will, Chem. Analyse ; Fre-
senius, Anal. Chem. ; Heintz, Zoochemie ;
Gorup-Besanez, Zooch. Anal. ; Schmidt,
Entw. ein. allg. Untersuchungsmethode ;
Hoppe-Seyler, Tr. d'anal. chim. phys. et
path. ; Miller, Chem. ; Watts, Diet. ; Roscoe,
Lessons #<?., and his larger work ; Engel.
Chim. med. et biol. ; Mehu, Chem. med. ;
Ralfe, Demonstr. in phys. and path. chem.

The progress of chemistry is reported in
the ' Chemical News.'

CHEY'LETUS, Latreille.— A genus of
Acarina (Arachuida), of the family Trom-
bidina.

Char. Rostrum prominent, palpi very
thick, resembling arms, and falciform at the
ends ; antennal forceps (mandibles ?) didac-
tylous ; tarsi with 2 simple claws. Koch
describes 6 species ; Michael and Megnin
add others.

C. eruditus (PL 53. fig. 13). Found in
books and museums. Parthenogenesis has
been found to occur in this species (Beck).
C. parasitivorus, found at the root of the
hairs of rabbits, feeding upon Listrophori ;
C. heteropalpus, on the feathers of the Co-
lumbidse &c. ; C. macronychus, on the fea-
thers of Insessores ; C. venustissimus, on
fodder in a stable ; and C.Jlabellifer, on the
walls of a beer-cellar (Michael).

BIBL. Geryais, Walckenaer's Aptei'es, iii.;
Koch, Dentsch. Crvstac. fyc. ; Robin, J. de
VAnat. 1867 (figs.), p. 506 ; Beck, Mic. Tr.
1866, 30 ; Murray, EC. Ent. 285 ; Michael,
Jn. Mic. Soc. 1878, 133 & 313 (figs.);
Megnin, Parasites, 1880, 240.

CHICKWEED, Stellaria media.— This
common plant is of great interest to the
microscopic observer, on account of the
facility with which the embryo-sac may be
dissected out. See Griffith, Text-book, 45,
pi. 1.

CHICORY.— This substance, used for
mixing with or adulterating coffee, consists
of the roots of the plant of the same name
( Cichonum Intybus). The structures com-
posing the root (PI. 2. fig. 6) are recognizable
after it has been roasted and ground, con-
sisting of membranous cellular tissue, c,
short-jointed reticulated ducts of large size,
b, and laticiferous tubes, a. Pure chicory
does not appear to contain any starch-gra-

nules, this substance being replaced by inu-
line in most of the plants of this family.
The presence of starch, therefore, in samples
of chicory denotes adulteration, which, when
effected by roasted corn or beans, is easily
detected ; and the integuments of roasted
grain may often be identified. Other com-
mon adulterations are roasted carrots, par-
snips, or mangel-wurzel : the first of these
is difficult to detect, as the structure of the
roots is very similar, as is the case to some
extent with the parsnip, in which, however,
traces of the starch usually remain; the
parenchymatous tissue of mangel-wurzel is
formed of cells very much larger than those
of chicory. In addition to the above, certain
substances containing astringent or colour-
ing-matters are occasionally found in ground
chicory and coffee — such as oak-bark and
tan, mahogany and other kinds of sawdust.
These are easily detected by the micro-
scope, from the presence of woody fibre and
liber-cells, the origin of which is often to
be made out by careful comparative exa-
mination.

BIBL. Hassall, Food and its Adulterations,
108, 199, 352.

CHI'LODON, Ehr.— A genus of Infu-
soria, of the family Trachelina.

Char. Body covered with cilia ; mouth
with teeth arranged in the form of a tube ;
fore part of the head produced into a broad
membranous or ear-like lip.

The cilia form longitudinal rows.

C. cucidlulus (PI. 30. fig. 27). De-
pressed, oblong, colourless, rounded at the
ends, slightly auriculate or beaked ante-
riorly on the right side; freshwater and
marine ; length 1-1120 to 1-140 '. (PL 30.
fig. 27 bj side view.) Contains a red eye-
spot.

C. undnatus. Depressed, oblong, rounded
at the ends, colourless ; narrowed and curved
anteriorly so as to appear hooked ; fresh w. ;
length 1-430".

C. aureus. Ovate-conical, turgid, golden-
yellow, anterior end curved so as to form
an obtuse beak, posterior end narrowed ;
aquatic ; length 1-140". A Nassula (?).

C. ornatus. Ovato-cylindrical, golden-
yellow, ends rounded, a violet spot at the
neck ; aquatic and marine ; length 1-174".
A Nassula (?).

Dujardin admits only the first species;
referring the others to the genus Nassida.

BIBL. Ehr. In/us. 336; Duj. Inf. 490;
Stein, Inf. &c. ; Claparede and Lachmann.
Inf. 335.

CHILOMONAS.

[ 166 ]

CHLORASTER.

CHILOM'ONAS, Ehr.— A genus of Fla-
gellate Infusoria, of the family Monadina.

Char. No tail nor eye-spot ; body ovoid,
oblong, surmounted by a lip ; with two very
delicate flagelliform filaments ; revolving
upon its centre.

C. volvox. Oval, narrowed and notched
in front, colourless and transparent, lip long;
fresh water; -length 1-1400".

C. paramecium. Oblong, keeled, trila-
teral, colourless and opaque, sometimes ag-
gregated; freshwater; length 1-1020".

C. destruens. Oblong, variable in form
from its softness, colourless or yellowish ;
fresh water and marine ; length 1-860".

C. granulosa (PI. 30. fig. 28). Oblong,
broader in front, colourless, with granules
which appear to project on the surface ;
length 1-840". In an infusion of mosses.

C. obliqua. Ovoid or pyriform, nodular,
colourless, variable in form ; length 1-2700".

BIBL. Ehrenb. Infos. 30; Duj. Inf. 295;
Kent, Inf. 423.

CHILOSTOMEL'LA, Reuse.— A Fora-
minifer, consisting of subovate chambers,
overlapping one another, almost completely,
on opposite sides alternately; with crescentic
almost terminal aperture.

Fossil (Tertiary), recent (Atlantic and
Pacific).

BIBL. Reuss. Denkschr. Ak. Wien, 1850,
i. 16 ; Brady, Qu. Mic. Jn. xix. 66.

CHIODEC'TON, Ach. — A semis of
Lichens (tribe Graphidei), of which one
species, C. myrticola, has been found in
Ireland ; and its var. sarniense in the Chan-
nel Islands.

BIBL. Leighton, Ang. Lich. 24, pi. 8. fig.
4, pi. 9. fig. 1 ; Lich. Flor. 435 ; Tulasne,
Ann. So. Nat. 3 ser. xviii. pi. 10.

OHIONY'PHE, Thienem.— A genus of
Mucorini (Phycomycetous Fungi), found
growing upon melting snow.

Chionyphe Carteri, Berk., is a curious
fungus, which is supposed to be the cause
of that formidable disease the Fungus-foot
of India. It has, however, been doubted
whether it is really the cause, or only
a secondary growth on the truffle-like
nodules composed principally of stearine (?)
which are characteristic of the disease.
Hogg considers the disease somewhat simi-
lar to the amyloid lardaceous disease which
attacks various other parts of the body.

BIBL. Thieneman, Nova Ada A. C. L. C.
xi. 1839; Ann. So. Nat. 2 se>. xiv. 63;
Intell. Obs. 1862 ; Berkeley, Jn. Linn. Soc.
viii. 141, pi. 10; Carter, Tr. Med. and Phys.

Soc. Bombay, 1861, 1862, 1863 ; Ann. N. H.
vol. ix. 442, 1862 ; Mn. Mic. Jn. 1871.

CHIROD'OTA, Eschsch.— A genus of
Echinodermata, closely allied to Synapta.

C. violacea possesses curious wheel-like
calcareous plates in the skin.

Not British.

BIBL. V. der Hoeven, Zool i. 150 ; Car-
penter, Microscope, 564; Herapath,Qw. Mic.
Jn. 1865, 1.

_ CHITINE is the horny substance which
gives firmness to the tegumentary system
and other parts of the Crustacea, Arachnid*.
and Insects ; probably also the carapace of
the Rotatoria consists*of it. It is left when
the above structures are exhausted succes-
sively with alcohol, ether, water, acetic acid,
and alkalies, retaining the original form of
the texture. It is dissolved by concentrated
mineral acids without the production of
colour. It is not dissolved by solution of
potash, even when boiling. Neither does it
give the characteristic reactions withMillon's
or Schultze's tests. It contains nitrogen.

BIBL. Odier, M6m. Mus. d'Hist. N. i.
p. 35 ; Lassaigne, Compt. Rend. xvi. p. 1087;
Schmidt, Vergl. Phys. d. wirbellos. Thiere
(Taylor's Sc. Mem. v. p. 1) ; Payen, Compt.
Rend. xvii. p. 227.

CHLAMIDOCOC'CUS. See PEOTO-
coccus ; also Cienkowsky, Bot. Zeit. 1865 ;
Rostafinsky, ibid. 1871 ;" and Rabenhorst.
Fl.Alg. iii. 94.

CHLAMLD'ODON, Ehr.— A genus of
Infusoria, of the family Euplota.

Char. Furnished with cilia and a cylinder
of teeth, but neither styles nor hooks. (Oxy-
tricha with a lorica and teeth.)

C. mnemosyne (PI. 30. fig. 29) . Elliptical
or the anterior end somewhat broader, ovate;
green or colourless, and containing rose-red
vesicles ; lorica projecting beyond the body ;
length 1-570 to 1-240"; marine.

BIBL. Ehr. Infus. 376 ; Kent, Inf.

CHLAMIDOM'ONAS (PI. 30. fig. 30 a,
b} c, d, e). See PBOTOCOCCUS.

CHLAMYDOCYSTIS, Grunow, = P>-o-
tococcus, part.

CHLORAN'GIUM, Stein, =COLACIUM.

CHLORAS'TER, Ehr.— A genus of Fla-
gellate Infusoria.

Char. Single, free, a single frontal eye-
spot, no tail, middle of the body with 'ra-
diate warty processes.

Allied to the genera Glenomorum and
Phacelomonas. Does not admit coloured
particles.

C. gyrans. Green, fusiform, acute at the

CHLOEATE.

[ 167 ]

CHLOROGONIUM.

ends; radiate processes in a whorl of four
at first obtuse, then subacute ; flagelliform
filaments 4-5 ; length 1-1630"; fresh water
It revolves radidly upon its axis, anc
undergoes spontaneous division.
Two other species, one marine.
BIBL. Ehr. Ber. Berl Ak. 1848, 236
Kent, Inf. 315.

CHLORATE OF POTASH. See POTASH.
CHLO'REA,NyL— A genus of Lichens,
family Lichenacei, tribe Usnei.

6 species. C. vulpina occurs in Europe.
BIBL. Nyl. Syn. 274, pi. 8. f. 1&-15; Jacq.
Misc. ii. pi. 10. fig. 4.

CHLORIDES. See the bases.
CHLOROCHYT'RIUM, Cohn.— A ge-
nus of Confervoid Unicellular Algae, allied
to Hydrocytium, Characium, and Chytridium ;
consisting of single, globose-ovoid, or irre-
gularly curved, 2-3- or multilobed cells,
densely filled with green protoplasm ; first
dividing into larger segments, then separa-
ting into innumerable pyriform zoospores,
escaping through a tubular process.

C. lemnce. In the parenchyma of Lemna
trisulca ; diam. a£o"«

BIBL. Cohn, Beitr. i. 1, 87 ; Wright, Tr.
Irish Acad. xxvi.

CHLOROCOC'CUM, Grev. — A genus
of Palmellaceas (Confervoid Algae).

We have assigned to this the common
green pulverulent stratum which is found
upon every old tree, on all old palings and
other exposed woodwork, &c. If this proves
to be really a distinct plant, and not an
accumulation of germinating gonidia of
Lichens, it will still differ from the plants
we have assembled under the name of Pro-
tococcus in its general habit, especially in
the absence of zoospores. This point is,
however, still open to inquiry, since it
appears that the gonidia of the Lichens do
divide into two, four, and eight, to form a
pulverulent stratum, which exactly repre-
sents Chlorooocewn and Protococcus.

Chi. wdgare, Grev. (PL 7. fig. 1). A
collection of extremely minute cells, multi-
plying by division into twos and fours, no
gelatinous substratum, no zoospores. Dia-
meter of single ceUs 1-3000 to 1-4000"
(Protococcus viridis, 1-2000 to 1-3000"). Old
dry palings, bark of trees, &c. everywhere.
Calculating from the known size of the cells
and the wide distribution, this, if a species,
would appear to be the most fecund Alga
in existence. There are 300 millions of in-
dividuals on a square inch, in a layer 1-100' '
thick ; and such layers clothe almost every

piece of unpainted timber and old trunk we
meet with in the country. C. murorum, Gr.
is perhaps a Palmogloea, Kiitz.

Rabenhorst remarks that this species
closely resembles the gonidia of Lichens,
but that the cells have a nucleus, which is
wanting in the Lichen-gonidia. This is,
however, incorrect, as the nucleus is quite
distinct in these gonidia.

Rabenhorst describes 12 species ; but
places C. vulgare in the genus Pleurococcus.
BIBL. Greville, Crypt. Fl. pi. 262 ; Has-
sall, Alga, pi. 81. fig. 5.

CHLOROGO'NIUM, Ehr.— A genus of
Infusoria, of the family Astasiaea.

Char. A red eye-spot, a tail, and two
anterior filaments. (Not attached by a fixed
pedicle.)

C. euchlorum (PI. 30. fig. 31). Spindle-
shaped, acute at each end, tail short ; length
1-1150 to 1-280". Found in enormous
numbers in pools and puddles ; frequently
as many as 10,000 in a single drop.

These organisms do not admit colouring-
matter or foreign bodies ; hence they are
probably not Infusoria, but Algae. They
often adhere to each other in groups by the
so-called tails (PL 30. fig. 31, upper figure),
sometimes to foreign bodies (PL 30. fig. 31,
lower figure), which exhibits them adhering
to a dead Vorticelld).

They undergo oblique spontaneous divi-
sion (PL 50. fig. 1) ; this commences in
the internal substance, which is constricted
before the outer portion.

They also propagate by a process of
swarming, which takes place thus : the in-
ternal substance first separates somewhat
from the transparent wall, subsequently
becoming irregularly constricted at various
parts. The constrictions deepening, the con-
stricted portions separate from each other as
independent vesicles (?), and the internal
substance acquires the appearance of a black-
berry or bunch of grapes, consisting of a
fusiform aggregation of uniform longish oval
granules. Up to this period, the parent
organism continues its movements ; subse-
quently these cease. The granules have
now acquired independent vitality, and their
ilaments become developed. The envelope
:hen breaks near its middle, and the swarm
of young ones escape. In their somewhat
more developed stage they form Glenomo-
-um tingens, Ehr. See PROTOCOCCUS.

BIBL. Ehr. In/us. 113; Weise, Wieg-
manrfs Archiv, 1848, i. 65; Stein, Infus.
188.

CHLOROPHYLL.

CHLOROPHYLL.

CHLOR'OPHYLL (leaf-green). — The
name applied to the green colouring-matter
of plants. The nature of the substances which
are understood under this term is still some-
what questionable. It is ordinarily stated
that chlorophyll exists commonly under the
form of globules or granules, and occasion-
ally as an amorphous granular substance,
in either case more or less adherent to, or
imbedded in the primordial utricle of the
cell. It is, however, a contested point
whether the chlorophyll-corpuscles are se-
misolid homogeneous globules in which the
chlorophyll is imbedded, or vesicles com-
posed of a delicate membrane enclosing a
green liquid : the former view is now, how-
ever, generally adopted. Chlorophyll pre-
sents itself in the form of distinct corpus-
cles (ffranules of authors), in the cells of
the flowering plants generally, particularly
the parenchyma of leaves and the subepi-
dermal parenchyma of green stems and
shoots. The granules are especially large
and distinct in certain water-plants, and
may be well seen lying scattered, singly,
imbedded in the circulating protoplasm of
the cells of the leaves of Vallimeria and
other water-plants. The corpuscles are very
evident in the cells of the prothallia of
Ferns, in the leaves of Selagine.lla, of Mosses
and Liverworts ; also in Chara, where they
are very abundant and form a continuous
layer, or numerous rows, embedded in a
gelatinous stratum between the cell-wall
and the circulating mass of protoplasm. In
the Confervoids the chlorophyll often ap-
pears both formless and corpuscular in one
and the same cell, but usually more or less
formless in young cells, and more com-
pletely converted into granules in the full-
grown, as in Vaucheria. In the Confer-
vaceee, such as Cladophora, and in (Eclogo-
nium, it presents itself in a granular stratum
with numerous larger bright corpuscles ;
and in Spirogyra, Zyynema, &c. the chlo-
rophyll takes the form of the spiral or an-
nular band to which it is adherent, without
large granulations in the general mass, but
with a number of distinct, large, bright-
looking corpuscles at intervals (PI. 9. fig.
18). In Protococcus, in zoospores, and in
the individual ciliated bodies of the Vol-
vocineee, the chlorophyll appears to tinge
the general mass of granular protoplasm,
leaving the conical apex (beak) uncoloured
(Plates 7 & 9), while more or less distinct
corpuscles or granules are scattered through
the mass, varying in number and size at

different periods. When any of these forms
of chlorophyll are treated with ether, benzole,
alcohol, or chloroform, the colour is abstract-
ed, while the organized forms, the corpuscles,
&c., remain ; so that the true chlorophyll is
really only a soluble substance, dyeing the
bodies called chlorophyll-corpuscles &c.
It becomes a question then whether these
are homogeneous semisolid corpuscles, or
vesicles containing the colouring-matter in
sacs, from which it is extracted by the ether
&c. Nageli and others assert the vesicular
character of the chlorophyll-corpuscles and
the appearances are sometimes much in
favour of this view ; but in the many cases
in which we have obtained the appearance
of a double line around them, under high
magnifying powers, we have never been
able to divest ourselves of the impression
that this was an optical illusion. Nageli
asserts that the corpuscles multiply by di-
vision, which is true, but does not prove
that they are vesicular structures. The ob-
servation of Giippert and Cohn, of a chlo-
rophyll-corpuscle swelling up and bursting
through enaosmose, may be explained with-
out supposing a regularly organized coat.
We are inclined to believe that the bodies
bearing the green colouring-matter are
structures belonging to the protoplasm, the
green colour being only an additional cha-
racter, produced by the action of light,
superadded to the ordinary character of the
granular structurs occurring in the proto-
plasm or nitrogenous cell-contents. See
PROTOPLASM.

A very important point connected with
chlorophyll is its relation to starch. The
bodies called starch-granules occur very
commonly with chlorophyll-corpuscles in
the cells of the green parts of plants, and
they become substituted for each other
under varying circumstances. Some authors
have imagined that chlorophyll is produced
by a chemical decomposition of starch,
while others think that starch is developed
from chlorophyll. The chief ground for
the latter view is the fact that starch-
granules are often found in the centre of
chlorophyll-corpuscles, like a kind of nu-
cleus. We have traced, in Hepaticae, the
gradual formation of a group of starch-
granules in the interior of a chlorophyll-
corpuscle (where they are readily detected*
by the application of iodine) ; and this goes
on in certain cases until almost all the green
colour is lost. Starch occurs universally
at a certain period in the bright ' distinct

CHLOROPHYLL.

[ 169 ]

CHLOROPHYLL.

chlorophyll-corpuscles of Chara and of
the Oonfervaceee, Spirogyra &c.; so that
these are coloured blue by iodine, although
green before its application. But this starch
may disappear again in the course of nature,
for it always vanishes from these corpuscles
when they are about to become organized
into zoospores. In fact the green chloro-
phyll is predominant during active vegeta-
tion, and starch in periods of rest or in full-
grown structures. Moreover, while chloro-
phyll may appear independently in young
cells without being preceded by starch, in
green tissues starch makes its appearance
without previous existence of chlorophyll-
corpuscles in subterranean structures, as for
example in the potato and other tubers.
The truth of the matter therefore appears to
be, that the chlorophyll-structures, as above
stated, are granular structures belonging to
the general protoplasm or nitrogenous cell-
contents, that they become coloured green
in the light by a chemical change connected
with the vital processes, and that in under-
going this change they do not lose the power,
which the ordinary protoplasm possesses, of
secreting starch and decomposing it again
when required for the nutrition of the plant.
Starch-granules, when free and uncoloured,
appear to be produced originally from gra-
nular or vesicular protoplasmic structures,
only differing by absence of colour from
chlorophyll structures. For example, the
granular protoplasm around the cell-nucleus
in the cells of herbaceous Monocotyledons
(such as the Lily, Tradescantia £c.) will
sometimes become converted into chloro-
phyll- granules (in superficial cells), inside
which starch may be subsequently deve-
loped ; but (in deeper-seated cells) the
granular protoplasm may give rise at once
to starch-granules (PL 46. fig. 28 a) with-
out the previous existence of the green
modification of the protoplasm, i. e. chloro-
phyll.

The views of the nature of chlorophyll
above expressed (in the first edition of this
work) have been since confirmed by the
observations of v. Mohl and Gris ; and re-
peated observations have furnished us with
similar results. In Caspary's observations
on Hydrillese also, will be found confirma-
tion of the statement that the supposed
vesicular structure is an illusion.

Chlorophyll occurs in the animal, as well
as in the vegetable kingdom — thus in Infu-
soria (Stentor &c.), the zoophytes (Hydra),
the Turbellaria, Aphidae, &c.

Chlorophyll-corpuscles, when set free in
water, expand by imbibing water, some-
times becoming vacuolated and bursting.
Alcohol and most acids coagulate them,
while acetic acid will often blend the cor-
puscles into an irregular mass.

After the separation of the chlorophyll,
the protoplasmic base retains both its form
and volume j constituting a solid soft body,
often containing small vacuoles.

Chlorophyll is turned yellow-brown by
tincture of iodine ; sulphuric acid gives it a
more or less deep blue colour ; ether and
alcohol discharge the green tint. Prepara-
tions mounted in chloride of calcium or
glycerine often lose their green colour ; those
preserved in water wih1 sometimes retain it
a long time. The green colouring-matter
extracted by alcohol is a complex substance,
containing a kind of wax and a matter
allied to indigo.

It was formerly considered that chloro-
phyll was the only colouring-matter of
plants, capable under the influence of oxy-
gen of producing all the varied and beauti-
ful colours of flowers. Subsequently, two
colouring-matters, a blue-phyllocyanine, and
a yellow-phylloxanthine, have been sepa-
rated by chemical reagents, and considered
as the real colouring-matters, which by
their mixture produced the most varied
colours. The old view has lately been re-
vived ; but the whole question must at
present be considered as unsettled.

In autumn, at the fall of the leaf, the
chlorophyll becomes dissolved, and con-
veyed to the perennial portions of the plants,
the cells become filled with liquid contain-
ing crystals and a number of bright yellow
granules ; if the leaves are red, this arises
from a substance dissolved in the liquid, the
yellow granules being also present.

BIBL. Mohl, Veget. Cell. (Trawl. 1852),
41 ; Vermischte Schriften, 349 ; JBotan. Zeit.
1855 (Ann. N. H. 2nd ser. xv. 321);
Nageli, Zeitsch. f. wiss. Bot. iii. 110 (Ray
Soc. 1849); Mulder, Physiol. Chem., Tr.
266 ; Goppertand Cohn, Bot. Zeitung, 1849,
vii. 665; Schleiden, Grundziige wiss. Bot.
3rd ed. 196 ; Braun, Verjung. (Ray Soc.
1853, 195); Morot, Color. desVegetaux,Ann.
Sc. Nat. 3 ser. xiii. 160 ; GuiUemin, Ann.
Sc. Nat. 4 ser. vii. 155; Gris, ibid. 1857,
vii. 179; Caspary, Pi'ingsheims Jahrb. wiss.
Bot. i. 399, ibid. 1881; Fremy, Compt.
Rend., 1. 405 ; Gmelin, Handb. Chem. vii.
1430 ; Hofmeister, Pflanzenzelle, 1867, sect.
41 ; Kraus, Jahr. wissensch. Bot. 1871, viii.

CHLOROPTERIS.

[ 170 ]

CHOLERA.

131; Henfrey-Masters, Bot. 498; Sachs,
Sot. 729 ; Sorby, Beale, How $c., 278 ;
Kraus, Z. Kenntniss. d. Chi. Farbstoffe, 1872
(Spectroscope) ; Askenasy, Bot. Zeit. 1867,
225 ; Geddes, Proc. Roy. Soc. no. 194 (Qu.
Mic. Jn. 1879, xix. 434) ; Palmer, M. M. J.
1877, xvii. 225 (figs.).

CHLOROPTERIS, Mont.— A genus of
Confervaceae (Confervoid Algae).

1 species : not British. Rabenhorst, Fl.
Alg. iii. 346 (fig.)-

CHLOROSPH^E'RA, Henfrey (EnE-
MOSPH^RA, De Bary). — A genus of Uni-
cellular Algae, probably related to (Edo-
goniege (Rabenhorst places it among the
Palmellaceae) ; of which one species, C. Oli-
veri (E. viridis, De B.) (PI. 5. fig. 4) is
known, consisting of a single globular cell,
about 1-200" in diameter, densely filled with
green contents, sometimes exhibiting a radi-
ated appearance. The cell is multiplied by
dividing into two parts by a septum, and
forming a new perfect cell in each half, the
two new cells escaping through slits in the
parent-cell membrane, with elasticity, when
mature. Resting-spores, formed in fours
in a parent-cell and of a brown colour, have
been observed, but not their germination
nor any formation of zoospores. C. Oliveri
was found in a boggy ditch, at Prestwich
Car, Northumberland. It has been found
elsewhere in turfy pools.

BIBL. Henfrey, Mic. Trans. 1859, vol. vii.
25 ; De Bary, Conj. 56.

CHLOROTYLIUM, Ktz.— A genus of
Chsetopboraceae (Confervoid Algae).

Char. Filaments jointed, repeatedly di-
chotomous, parallel ; joints of two kinds,
some elongate and colourless, others swol-
len, abbreviate, and with green endo-
chromes.

4 species. On rocks, submerged timber,
and the bottom of ponds.

BIBL. Kiitzing, Sp. Alg. 432 ; Raben-
horst, Fl. Alg. iii. 386 (fig'.).

CHOCOLATE. See COCOA.

CHCE'NIA, Quennerstedt. — A genus of
Holotrichous Infusoria.

Char. Free, elongate, with a brush-like
tuft of large cilia at the anterior extre-
mity.

C. teres, marine, = Trachelius t. Duj.

BIBL. Kent, Inf. 521.

CHOIROMY'CES.— A genus of Tube-
racei (Ascomycetous Fungi) characterized
by a definite base, even common integu-
ment, clavate asci and spherical sporidia.

C. meandriformis, Vitt., occurs occasion-

ally in Great Britain. It sometimes attains
a considerable size.

BIBL. Vitt. Man. Tab. 50; Ann. N. H.
xviii. 80 ; Sow. Fung. t. 310 ; Tul. Fung.
Hyp. 170, tab. xix. fig. 7.

CHOLERA.— The attempt has often
been made to discover some animalcule or
minute vegetable organism in the air, water,
and the intestinal and other animal liquids,
during the existence of cholera, which might
explain the origin of this fearful disease ;
and statements have been published an-
nouncing success. None of these have,
however, stood the test of rigid investiga-
tion. When the cholera prevailed at Berlin
in 1832, the renowned Ehrenberg, who had
then been engaged in the study of micro-
scopic organisms for many years, declared,
after special and careful examination, that
neither the air nor the water from various
localities contained any thing unusual. Re-
peated examinations of the air and water
of infected, localities, made in 1849, and
during the more recent accessions of the
cholera, have afforded also conclusive nega-
tive evidence.

Hallier subsequently attempted to show
that it was probably derived in the first in-
stance from a fungus infesting rice. It is,
however, a remarkable fact that rice is far
less subject to attacks of Fungi than any
other cereals. The researches of Thwaites
and others have been directed to this espe-
cial point, and have in no respect confirmed
Hallier's views ; added to which, it was
quite evident that the fungus which ap-
peared in cholera-evacuations was not the
Urocystis, to which he referred it. De
Bary altogether denied the justice of his
views. Lewis and Cunningham were placed
by the government authorities in communi-
cation with De Bary and Hallier, and quite
accorded with the former of the two ; and
the very careful observations of Lewis at
Calcutta confirm De Bary's views. See
MICROZYMES.

The methods of examining the air in re-
gard to this point are described under
AIR.

BIBL. Baly and Gull, Hep. of Cholera
Subcommittee of Roy. Coll. Phys., London,
1849; Robin, Veget. Parasites, fyc., 1853,
appendice, 676 ; Hallier, Das Cholera-
Contagium; Privy Council Reports, 1866 and
1870;' Sansom, Jn. of Science, 1871, 153;
Berkeley, Mic. Jn. July 1869 ; Lewis, Re-
port on Objects found in Cholera-evacuations;
and Med. Chi. Rev. 1871.

CHOLERA-FLY.

CHORDA DORSALIS.

CHOLERA-FLY.— Knox, Lancet, 1853,
ii. 479.

CHOLES'TERINE. — This substance
exists naturally in most animal liquids in a
state of solution ; also in many animal solids,
as in the blood, the bile, the meconium,
the brain and spinal cord. As an abnormal
product, it occurs in the crystalline form in
the bile, biliary calculi, various dropsical
effusions, the contents of cysts, pus, old
tubercles, malignant tumours, the excre-
ments, expectoration of phthisis, &c.

In the vegetable kingdom it occurs in
peas, beans, almonds, many seeds, &c.

The crystals form thin pearly rhombic
plates (PI. 13. fig. 21). The acute angles
are =79° 30', the obtuse =100° 30'. Some-
times the angles are truncated.

Cholesterine is insoluble in water and
solution of potash, even when boiling ; but
soluble in ether and boiling alcohol, crystal-
lizing on cooling.

It is most easily procured from a gall-
stone by boiling in alcohol ; it falls on cool-
ing. The crystals thus obtained are usually
thicker than the natural plates.

CHONDRACAN'THUS.— A genus of
Crustacea, of the order Siphonostoma, and
family Lernasopoda.

C. Zei. Found upon the gills of Zeus,
the Dory. Body is covered with short re-
flexed spines. Length 4-5".

BIBL. Baird, Brit. Entomostr. 327 ; Me-
gnin, Parasites, 442.
' CHONDRIA, As-. See LAUREXCIA.

CHONDR1NE.— The gelatinous matter
of the permanent true cartilages.

Its solution differs from that of the gela-
tine of bones &c., in being precipitated by
acetic acid, acetate of lead, and alum. The
acetic precipitate is insoluble in excess.

It is coloured red by Millon's test ; but is
unaffected by that of Pettenkofer.

CHON'DRUS, L.— A genus of Crypto-
nemiaceae (Florideous Algae), composed of
cartilaginous sea-weeds with flat dichoto-
mously-divided fronds, the cellular structure
of which exhibits three layers — a central of
longitudinal filaments, an intermediate of
small roundish cells, and an outer of ver-
tical coloured and beaded rows of cells,
the whole imbedded in a tough <f inter-
cellular" matrix. See INTERCELLULAR

SUBSTANCE.

Fructification : spores contained in favel-
lidia immersed in the frond ; tetraspores
collected in imbedded sori ; and " nema-
thecia,"1 tubercles composed of radiating

filaments (antheridia ?). C crispus becomes
horny when dry, and is the Irish moss or
Carrageen of the shops.

BIBL. Harvey, Br. Mar. Alg. pi. 17 D ;
Phyc. Brit. pi. 63 & 187 ; Greville, Alg.
Brit. pi. 15.

. CHOR'DA, Stackh.— A genus of Larni-
nariaceae (Fucoid Algae), with fronds of
a peculiar, simple cylindrical form ; two
species, C.Jilum and C. lomentaria, are found
between tide-marks on British coasts ; the
former grows from 1 to 20 or even 40 feet
long, with a greatest diameter at half its
length, of 1-4 to 1-2". The cord-like frond
is tubular, but has at intervals thin dia-
phragms, formed by interwoven transparent
filaments. The wall of the tube is com-
posed of a number of layers of very regular
six-sided cells, upon which are implanted
little erect clavate cells which coat the
entire surface of the frond. These present
two forms, apparently constituting oospo-
ranges (spores, Harvey, paranemata, Ag.)
and trichosporanges, (antheridia, Harvey,
spores, Ag.). The first are single sacs pro-
ducing a number of zoospores; the second
are filaments composed of about five joints,
each of which gives birth to a zoospore.

BIBL. Harvey, Br. Mar. Alg. 31, pi. 3 B;
Phyc. Brit. 107, &c. ; Thuret, Ann. Sc. Nat.
3 s^r. xiv. 240, pi. 29. figs. 5-10 ; Derbes
and Solier, Ann. Sc. Nat. 3 se*r. xiv. 268,
pi. 33, figs. 7-10 ; Kiitzing, Phyc. gen. pis.
28 & 29.

CHORDA DORSA'- r- 12a
LIS, or NOTOCHORD. — ,

The embryonic represen- . ••*

tative of the spinal co-
lumn of the Vertebrata ;
the permanent spinal
column of the Cartilagi-
nous Fishes. It some-
times forms a spindle-
shaped, transparent, gela-
tinous-looking cord, with
the broadest part near
the tail; at others it is
cylindrical or conical,
rounded anteriorly and
tapering posteriorly.

It usually consists of
an outer comparatively
thick and firm structure-
less membrane, forming of ^ sheep! rathermore

a sheath, and of pale nu- than 1-2" in length, o,
cleated cells, which fill sheath; b, cells.
the sheath (fig. 126). In
some instances, however, its structure is

Magnified 350 diam.
Portion of the chorda

CHORDARIA.

[ 172 ]

CIIROMOPIIYTON.

fibrous, and that of the sheath fibro-mem-
branous. The cells are mostly angular or
polyhedral, and closely crowded. Their
size varies ; in the embryo of a sheep rather
more than 1-2" in length, they measured
about 1-1800".

The walls of the cells readily dissolve in
solution of potash ; but they yield neither
gelatine nor chondrine on boiling. The
liquid within the cells is not coagulated by
boiling, but the chorda itself becomes cloudy
and granular.

In its earlier stage of development, the
chorda consists simply of a longitudinal
band of ordinary formative or embryonic
cells; the sheath is subsequently formed.
It appears that the spinal column is not
developed from the chorda itself, but from
a blastema secreted by its component cells
and effused around them.

The chorda is most readily examined in
the larvae of frogs (tadpoles), of Tritons,or of
Fishes, and may be separated by macerating
the dead animals for twenty-four hours in
water. On cutting off the tail, it may then
be pressed out by gently scraping along its
course from the end of the tail, or from the
head towards the wound. It is a beautifully
delicate structure, and closely resembles in
appearance a piece of vegetable cellular
tissue.

BIBL. Kolliker, Mikr. Anat. ii. 346;
Stannius, Vergl. An.\ Gegenbaur, Verg.An.
450 ; Frey, Hist. 197.

CHORDA'RIA, Ag.— A genus of Chor-
dariaceae (Fucoid Algae), remarkable for the
solidity of the cellular texture of the fili-
form fronds. The axis and branches are
composed of a central mass of longitudinal
cells, upon which stand horizontal clavate
filaments, formed of a row of beaded cells,
constituting a distinct peripheral layer,
which gives a velvety texture and slimy
character to the surface. The so-called
spores attached to the horizontal filaments
are oosporanges, and discharge zoospores
when mature ; trichosporanges have not yet
been observed. C. flagelliformis, Miill., is
common on rocks and stones between tide-
marks.

BIBL. Harvey, Br. Mar. Alg. pi. 10 A ;
Phyc. Brit. pi. Ill ; Thuret, Ann. Sc.
Nat. 3 ser. xiv. 237.

CHORDARIA'CE^E.— A family of Fu-
coid Algae. Olive-coloured sea-weeds with
a gelatinous or cartilaginous, branching
frond, composed of vertical and horizontal
filaments interlaced together; the oospo-

ranges and trichosporanges attached to the
filaments forming the superficial layers of
the frond. British genera :

Chordaria. Axis cartilaginous, dense fila-
ments of the circumferance unbranched.

Mesoyloia. Axis gelatinous, loose fila-
ments of the circumference branching.

BIBL. Harvey, Marine Algce ; Thuret,
Ann. Sc. Nat. 3 ser. xvi. 5, &c. See also
the genera.

CHORIOPTES, Gervais.— A subgenus
of Sarcoptes, with the body bilobed, or
notched posteriorly, the mandibles short,
didactylous, the tarsi with strong claws,
and very large suckers.

C. bovis (spathiferus) ; on the legs and
hind quarters of the horse, the goat, and
the ox ; C. setiferm, on the hysena and fox ;
C. ecaudatus, in the ears of dogs, cats. ;md
ferrets. There are other doubtful species.

BIBL. Me'gnin, Parasites, 198 (figs.) ;
Murray, EC. Entom. 312 (fig).

CIIORIZOPORA = Lepralia pt. C.
Brongniartii. Cells connected by a tubular
network. Marine.

BIBL. Hincks, Polyzoa, 222.

CHOROID MEMBRANE. See EYE.

CHROMATE OF LEAD (neutral) is one
of the best materials for colouring size in
injections. See INJECTION.

CHROMIC ACID may be prepared by
adding gradually from 120 to 150 part,*, by
volume, of pure concentrated sulphuric acid
to 100 parts of a cold saturated solution of
bichromate of potash. The crystals of the
acid separate as the solution cools. The
mother-liquor should be poured off, and the
crystals dried upon a tile; they may be
purified by re-crystallization from solution
in water. With excess of sulphuric acid,
chromic acid is a valuable reagent for
dissolving the intercellular substance of
plants.

Chromic acid is readily decomposed by
organic matter, as dust &c., and must
therefore be preserved in a well-stoppered
bottle. Its aqueous solution, which should
be of a pale yellow colour, is used for
hardening and preserving nervous and mus-
cular tissues, &c. It should be prepared
when required.

CHROMOPH'YTON, Woronin. — A
doubtful organism, probably allied to the
Palmellaceae, forming a yellowish-brown
dust on the surface of boggy pools (Finland).
Two forms were met with : the larger con-
sisted of spherical moniliform or variable
bodies, composed of a hyaline matrix, con*

CHROOCOCCUS.

[ 173 ]

CHYLAQUEOUS.

taming rounded or ribbon-shaped yellow 1-
ciliated zoospores, 1-3000" long, each with a
yellow pigment-spot, and containing one
or two contractile vesicles ; these multi-
plied by division. The finer had the same
composition as the larger. Resting-spores
were formed in the empty cells of Sphagnum
and Hypnum, from which the motile forms
were traced.

C. Rosanoffii, the single species.

BIBL. Woronin, Bot. Zeit. 1880, 625,
641 ; Jn. Mic. Soc., 1881, i. 100.

CHROOCOC'CUS, Nag. See PBOTO-
coccus. Rabenhorst retains this, as a
genus, with 23 species.

CHROOLEPUS, Ag.— A generic name
applied to certain byssoid structures found
on rocks, bark of trees, &c. They consist
of jointed, variously branched filaments, the
joints expanding to form sporangia, filled
with biciliate zoospores. C. aureum (PL
3. fig. 7) is composed of rigid opaque, ulti-
mately brittle filaments, forming soft cush-
ions of a yellowish colour; C. Jolithus,
odoratum, and lichenicola are of orange or
fulvous colour. Another series of species,
C. ebenea &c., are black, or purple. These
plants have been regarded sometimes as
Fungi and sometimes as Algae.

Rabenhorst describes 11 species: the
genus forming the type of the family Chro-
olepidse (Confervoid Algae). Reproduction
by biciliated zoospores. Some species emit
a violet-odour.

BIBL. Hooker, Brit. Flora, v. pt. 1. 384 ;
Engl. Bot. pi. 702 & 1639 ; Kiitzing, Spec.
Alg. 425; Caspary, Flora, 1858, 661 5 Ra-
benhorst, Fl. Alg. iii. 371.

CHRYSALIDI'NA, D'Orb.— A Textu-
larian Foraniinifer, with a triserial arrange-
ment of chambers and with large pores,
and sometimes tubes, opening from chamber
to chamber. Ch. gradata, D'Orb., is from
the Cretaceous strata of France. A dimor-
phous form, which is uniserial in its old
state, lives in the Indian ocean and Panama
Bay.

BIBL. D'Orbiguy, For. Fo*s. Vien. 194;
Carpenter, Introd. For am. 193.

CHRYSIME'NIA, J. Ag.— A genus of
Laurenciaceae (Florideous Algae).

C. clavellosa is a red sea-weed 3 to 12"
high, forming a feathery frond composed of
a branched, tubular, long, not constricted or
chambered, cellular structure, filled with a
watery juice. The spores are angular and
are contained in dense tufts in ceramidia
borne on the sides of the branchlets. The

tetraspores are 3-partite and immersed in
the branchlets.

BIBL. Harvey, Br. Mar. Alg. pi. 13 A;
Phyc. Brit. pi. 114.

CHRYSO'MONAS, Stein.— A genus of
Flagellate Infusoria.

C. fla means = Manas fl. Ehr. ; has the
body ovate, a terminal flagellum, two
lateral colour-bands, no dilated pharynx,
and an eye-spot. Ditch water.

BIBL. Kent, Infus. 408.

CHRYSOPYX'IS, Stein.— A genus of
Flagellate Infusoria.

Char. Bodies ovate, contained in a sessile
lorica ; flagella 2, equal ; two colour-bands,
but no eye-spot.

C. bipes. Lorica with two posterior
spines. Attached to the cells of Mougertia
or other freshwater algae.

BIBL. Kent, Infus. 408.

CHTHONOBLAS'TUS, Kiitz. See Mi-

CBOCOLEUS.

CHY'DORUS, Leach (Lynceus, Miill., in
part). — A genus of Entomostraca, of the
order Cladocera, and family Lynceidae.

Char. Nearly spherical ; beak very long
and sharp, curved downwards and forwards ;
inferior antennae very short.

C. sphcericus (PI. 20. fig. 7) . Shell smooth ;
olive-green. Found in ponds and ditches.

C. globosus. Shell more rounded than in
the last, and nearly six times as large ; an-
teriorly reddish, with circular striae and
numerous black spots ; fresh water.

BIBL. Baird, Brit. Entom. p. 125 ; Nor-
man and Brady, Brit. Enton. pp. 47, 48.

CHYLA'QUEOUS or chylo-aqueous li-
quid and system.

In the Invertebrata, two distinct kinds of
nutrient liquids exist. In some classes of
this subkingdom, these two liquids coexist
in the same organism, though contained in
distinct systems of conduits ; while in others
they become united into one. Williams
distinguishes these two kinds of liquid as
the blood proper or true blood, and the
chylaqueous liquid. The former is always
contained in definitely organized (walled)
blood-vessels, and has a determinate circu-
latory movement; the latter, with equal
constancy, in chambers, irregular perivis-
ceral cavities, and cells communicating in-
variably with the peritoneal cavity; not
having a determinate circulation, but a to-
and-fro movement, maintained by muscular
and ciliary agency. The true-blood system
does not exist under any form, even the
most rudimentary, below the Echinoder-

CHYLE.

[ 174 ]

CHYTftlDIUM.

mata ; in other words, the true-blood sys-
tem begins at the Echinodermata. Below
the Echinodermata, viz. in the Polypi and
Acalephee, the digestive and circulatory
systems are identified, consequently the ex-
ternal medium is admitted directly into the
nutrient vessels. This circumstance con-
stitutes a fundamental distinction between
the chylaqueous system and that of the true
blood, into which, under no conditions, is
the external inorganic element directly
introduced.

In every class in which the chylaqueous
liquid exists, it is charged more or less abun-
dantly with organized corpuscles. These
corpuscles are marked by distinctive cha-
racters, not in different classes and genera
only, but in different species, entitling these
bodies to great consideration in the esta-
blishment of species. In those classes, as
the Echinodermata, the Entozoa, and Anne-
lida, in which, in the adult animal, these
two orders of liquids coexist, though dis-
tinct, in the same individual, an inverse
proportion prevails between them, as re-
spects their magnitude or development.
The system of the chylaqueous liquid does
not exist in the adult, but only in the larval
state of the higher members of the articu-
lated series, as the Myriapoda, Insecta, and
the Crustacea.

BIBL. Williams, Trans, and Proc. of Ren/.
Soc. 1852 (the former contains figures of the
corpuscles); id. Ann. N. H., passim after
1852; Agassiz, Sieb. and Koll. Zeitschr.
1856, vii. 176; Nicholson, Zool. 1878.

CHYLE. — The chyle consists of a liquid
which coagulates when removed from the
vessels, containing in suspension molecules,
nuclei, colourless corpuscles, and coloured
blood-corpuscles.

The molecules (PI. 50. fig. 2 a) are very
numerous, and probably consist of fatty
matter surrounded by a coat of a proteine-
compound ; to them is owing the milky ap-
pearance which the chyle possesses during
active digestion. They form the molecular
base of Gulliver. The free nuclei (PI. 50.
fig. 2 6) have a somewhat homogeneous
aspect; they are not numerous, about
1-11,000 to 1-5600" in diameter, frequently
appearing cell-like and granular after the
addition of water. They are only met with
at the origins of the lacteals, in the mesen-
tery, and in the vasa efferentia of the me-
senteric glands, but never in the thoracic
duct. The chyk-corpusdes (PI. 50. fig. 2 c),
which are identical with these of the lymph

and the colourless corpuscles of the blood,
are pale, round, nucleated cells, 1-4500 to
1 2000" in diameter; their contents be-
come turbid when water is added; and they
are rendered very transparent by the addi-
tion of acetic acid, the granular nucleus
becoming at the same time very distinct.
Sometimes they exhibit a number of Amoe-
ba-like processes (PI. 50. fig. 2 d). At the
origins of the lacteals the chyle-corpuscles
are few in number, or even absent ; near the
mesenteric glands, they are met with under-
going division. The coloured blood-corpus-
cles are probably derived from without.
Chemically, the chyle consists of a saline
liquid, containing albumen and fibrine in
solution, the latter when coagulated form-
ing a soft and loose clot.

BIBL. Kolliker, Mikrosk. Anat. ii. 561 ;
Wagner, Handwort. art. Chylus ; id. Elem.
ofPhys., by Willis; Gulliver, Gerber's Anat.;
Lister, Dublin Hosp. Gaz. 1857, 347 ; Frey,
Histol. $c. p. 146 ; and the Bibl. of CHE-
MISTRY.

CHYLOCLA'DIA, Grev.— A genus of
Laurenciacese (Florideous Algae), containing
a few British species, with fronds of small
size, composed of a branched, cylindrical
and tubular structure, cut off into chambers
within by diaphragms at intervals, and filled
with a watery juice. The walls are com-
posed of small polygonal cells. Nageli has
given the minute anatomy ofC.(Lomentaria)
kalifornis. The spores are wedge-shaped,
contained in tufts in ceramidia borne on the
branchlets. The tetraspores, 3-partite, are
immersed in the branchlets.

BIBL. Harvey, Mar. Ala. pi. 13 B ; Phyc.
Brit. pi. 145, &c. ; Grev. Ala. Brit. pi. 14 ;
N&geli.Alfftn-wgteine, 246, pi. x. figs. 13-21.

CHYTRID'IUM, Braun.— A genus of
Unicellular Algae, perhaps allied to the JM y.\-
omycetes (Sachs), consisting of minute, glo-
bose or pyriforin, usually colourless cells,
operculate at the summit, with a root-like
base, attached to Confervoid or allied plants,
and penetrating their cell-walls. Zoospores
very numerous, globular, with a single very
long cilium.

C. olla (PI. 5. fig. 7).

The commonest form is that of a some-
what ovate cell 1-5000 to 1-2000" long,
sessile by the thick end on the outside of
the cell- wall of the plant it infests, and,
according to Braun and Cohn, sending fine
radical tubes into the interior ; the cell-
contents of the infested cell are usually
found disorganized and discoloured. In

CIBOTIUM.

[ 175 ]

CILIA.

another form, distinguished by Pringsheim
under the name of Pythium, the cells are
glohular and occur in the infested cells,
pushing a long tubular neck out through
the cell-wall. In both forms the contents
of the Chrytridium-cell are finally resolved
into ciliated gonidia, which escape and
swim about. In the external form, the cell
often opens by a lid (like the androspore
cells of (EDOGONIUM); in the internal form
the slender neck opens at the end. Braun
has described no less than twenty-three of
these obscure bodies, while Rabenhorst
admits six species; and they have been
observed by Cohn, who connects them with
Achlya, considering them aquatic fungi.
Carter has observed them in Spirogyra ; and
we have found both forms in and on the
cells of CHLOROSPHJERA. Braun and Cohn
declare them to be really foreign bodies,
that is, true parasites ; but we are not clear
on this point ; they seem rather products
of diseased protoplasm, if they be not modi-
fications of the antheridial structures of
some of the Confervoids.

BIBL. Al. Braun, Verjungung 8fc. (Ray
Transl. 1853, 185); Berl. AbhandL 1856, 2
(plates); Ueb. Chytridmm, Berlin, 1856;
Alg. Unicell. Gen. Nov. Leipsic, 1855 ; Bail,
Bot. Zeit. xiii. 678 ; Cienkowski, Bot. Zeit.
xv. 233 ; Carter, Ann. Nat. Hist. 2nd ser.
xvii. 101, and xix. 259 ; Bary & Woronin,
Ber. Geselhch. Freib. 1863 ; Woronin, Bot.
Zeit. 1868, 81 ; Nowakowski, Cohn, Biol. d.
Pfl.i.l, ii. 1877, 73, 201.

CIBOTIUM, Kaulfuss. — A genus of
Dicksonieae (Polypodiaceous Ferns) ; with
a bivalve indusium ; now made a subgenus
of Dicksonia.

BIBL. Hooker, Syn. Fil. 49.

Fig. 127.

Cibotium macrocarpum.
A pinnule with sori. Magnified 10 diameters.

CILIA (plural of ciUum) of ANIMALS. —
These are microscopic filaments attached by
one end to the surfaces of various parts of
animals, and exhibiting a vibratory or rota-
tory motion. They are usually rounded and

broadest at the base, tapering towards the
free end ; sometimes they are flattened.
Their length is very variable, having been
estimated at 1-50,000 to 1-500" ; probably
1-15,000 to 1-500" would include most of
them; in Bacterium termo they are
1-200,000" in diameter (Dallinger). The
larger size is attained by the cilia existing
on the point or angle of the gills or branchial
laminae of the whelk (Biiccinum undatum).

Numerous examples of animals furnished
with cilia, showing their appearance when
at rest, are figured in Pis. 30, 31, 32, 43, &
44. During life, and for some time after
death, they are usually in constant motion,
giving the parts of the field of the micro-
scope in which they are situated a tremulous
appearance when their motion is very rapid
and the cilia are very minute. When they
are large, as on the gills of the common
sea-mussel (MYTILUS), especially when
their motion is slackening, they are seen
waving to and fro, or lashing the water, and
producing in it strong currents, rendered
visible by the motion of minute particles
accidentally contained in the water. The
motion is mostly uniform, or in one direc-
tion; occasionally, however, it has been
observed to cease for a moment, and then
to assume an opposite direction to that pre-
viously exhibited. During the motion, the
whole filament is usually more or less
curved; but in some instances among the
Infusoria, the basal portion of the cilia re-
mains rigid, whilst the terminal portion
vibrates; under these circumstances the
cilia are distinguished as flagelliform fila-
ments. Sometimes the cilia move around
an imaginary perpendicular axis, in a rota-
ting direction.

Cilia are found in all the Vertebrata, and
in the Invertebrata, excluding the Crustacea,
Arachnida, and Insecta. We have, on two
occasions, distinctly obtained ciliated epithe-
lium, resembling that in PL 49. fig. 13, by
wounding the bodies of the larvae of garden-
moths ; but were unable to follow the obser-
vations. In Man, they spring from epithelial
cells ; the localities in whicn they are found
are stated under EPITHELIUM.

The uses of the cilia are of two kinds :
when the body to which they are attach'ed
is of no great bulk or specific gravity com-
pared with that of the medium in which
they reside, the cilia become organs of loco-
motion, as in the Kotatoria, Infusoria, the
young Acalephaa, the ovum, &c. ; but if
the inertia of the body be too great to be

CILIA.

C 170 ]

CILIA,

overcome by the feeble power of the cilia,
they produce motion in the surrounding
medium, as on the gills of fishes, of young
reptiles, and of the Mollusca, the gill-tufts
of the Annulata, and the various mucous
surfaces of the Vertebrata upon which they
exist, in which they favour respiration and
,excretion. By the same agency they also
bring particles of food suspended in the
medium towards the mouth. It need
scarcely be remarked, that the motion of
cilia must be stronger in one direction than
the other, otherwise there could be no
current.

The cause of the motion of cilia has long
formed a subject for discussion ; but it is
still unknown. In some instances, as in the
Infusoria, it appears to be voluntary. In
certain cases it might be attributed to the
action of a contractile amorphous tissue,
such as that composing the Amcebfs. It
would naturally be attributed to muscular
agency ; but no muscular tissue can be de-
tected : in fact, cilia are quite structureless ;
moreover they are often of less breadth than
the ultimate fibrillae of muscle. Neither
the most powerful poisons, as strychnine,
prussic acid, opium and belladonna, nor
electricity, produce any effect upon ciliary
motion, provided the structure unon which
the cilia are situated be not injured. It
also lasts a long time after death, having
been observed in the lower animals nineteen
days after this occurrence, and when putre-
faction was far advanced. The question has
however, lost its interest in regard to its ne-
cessary dependence upon muscular action,
because cilia are common among the lower
plants, where this is out of the question.

The cilia and their motion may readily be
observed in the common Rotatoria and Infu-
soria, or in a thin piece cut from the margin
of the gills of the oyster ; or still better, the
sea-mussel ; in the latter they form a most
beautiful and interesting object. Fresh
water almost immediately arrests the motion
of the cilia in marine animals. In some cases,
solution of potash excites the movement of
animal-cilia after it has become languid.

The detection of the cilia is frequently of
great importance, as the characters of Infu-
soria, &c. are often based upon their num-
ber and arrangement. The means are either
indirect — as by the addition of moistened
particles of colouring-matters, as indigo &c.,
to the living organisms, and watching for
the movements of the particles — or direct,by
examining the structures after the addition

of solution of iodine, bichloride of mercury,
or of osmic acid, or drying them at a gentle
heat. Both methods should be adopted to
check each other : for molecular movement
has some resemblance to ciliary motion
when feeble, although there is absence of a
definite current ; and fine hair-like Algae
or Fungi attached to aquatic organisms
often resemble cilia, but are deficient in the
motion.

See INFUSORIA ; MEMBRANES, UNDU-
LATING ; and MOLECULAR MOTION.

BIBL. Purkinje & Valentin, Comm. PJn/x.
$c. ; Sharpey, TodcTs Cycl. of An. $ Phys.
i. 606; Valentin, Wagners Handw. Phys.
fyc. i. 484; Virchow, Archiv, vi. 133; En-
gelmann, Jen. Zeitschr. iv. 321; Roth,
Virchow's Arch, xxxvii. 184; Ilackel's
JBiol. Stud. 147 ; Frey, Hist. 1876, 173.

CILIA of VEGETABLES. — These minute
vibratile threads, apparently of the same
(unknown) nature as those of animals, are
in all cases met with in connexion with the
protoplasmic or nitrogenous structures of
plants, the structure bearing the closest re-
lation to animal organization. Cilia have as
yet been found only in Flowerless Plants,
viz. in all the higher or stem. - forming
Cryptogams, and in the Algae among the
Thallophytes. In the Marsileaceae, Lyco-
podiaceae, Ferns, Equisetaceee, Mosses, He-
paticse, and Characese, they are found upon
the active filaments (spermatozoids) dis-
charged from the antheridia. In the Alga&
they occur upon the zoospores and some-
times upon the spermatozoids, and on the
fully-developed plants of the family Vol- .
yocmese. They have been stated to occur
in certain other complete organisms, as in
Clostenum ; but this statement we believe
to be erroneous. Rigid filaments bearing
some resemblance to cilia occur occasionally
upon Diatomaceae and OscillatorieaB ; but
tnese are not vibratile organs. The mode
of arrangement, &c. varies considerably
among the cases above cited. In the sper-
matozoids of the Marsileaceae, Lycopodi-
aceae, Ferns, and Equisetaceae, they are set-
in considerable number along a filament
spirally or heliacally coiled (PL 40. fig. 34).
In the Muscaceae, Hepaticae, and Characese,
a pair of very long cilia is attached at one
end of the filament (fig. 123, p. 162). In
zoospores, either they occur in a pair at
the apex, as in Protococcus^ Conferva, Cla-
dophora, Codium, &c., or there are four in
the same situation, as in Ulothrix, Ch<zto-
phora, Ulva, &c. ; while the large zoospores

CILIARY.

[ 177 ]

CIMEX.

of (Edoffonium bear a crown of vibratile
cilia, and the great elliptical zoospore of
Voucheria is clothed with them over its
whole surface. In the Volvocineae, there is
a pair of cilia attached, just like those of
zoospores, to each member of the family of
which the compound organism is made up ;
and these project through orifices in the
common envelope, so as to render the per-
fect plant locomotive, while the cilia of
ordinary zoospores disappear when they be-
come encysted in a cellulose coat prepara-
tory to germination. The spermatozoids of
the Fucaceae, and the zoospores produced
in the sporangia of other Fucoids have a
different arrangement of the cilia : there
are always two ; but they are attached on
a reddish point on the side of the zoo-
spore, not at its apex, and one of the cilia
is directed forwards from the apex or beak,
while the other trails behind like a kind of
rudder.

The mode in which these transitory cilia
are lost is variously stated : some authors
think they are retracted into the protoplasm ;
from what we have seen, we believe they are
thrown off entire. The cilia have the same
chemical reactions as the protoplasmic sub-
stance generally, and are apparently pro-
cesses of it; they are stained brown by
iodine, which also stops their motion and
renders them partly solid. The mode of
detecting and observing cilia is given in
the preceding article. Further particulars
of individual cases will be found under the
heads of the families and genera named above.

BIBL. Thuret, Zoospores des Algues, $c.,
Ann. des Sc. Nat. 3 ser. xiv. & xvi. ; Anthe-
r idies des Fougeres, Ann. Sc. N. 3 ser. xi.
5 ; Hofmeister, Vergleich. Untersuch. fyc.,
Leipsic, 1851 ; linger, Die Pflanze im Mo-
mente der Thierwerdung, 34, Vienna, 1843 ;
Al. Braun, Verjilngung, Sfe. (Ray Soc. 1853);
Cohn, Protococcus phivialis, Nova Ada A. L.
C. C. xxii. 735 (Ray Soc. 1853, 352) ; on
Stephanosph&ra, Siebold & Kolliker's
Zeitschr. iv. 77 (Ann. N. H. 2 ser. x. 321) ;
Henfrey (Ferns), Linn. Tr. xxi. ; Focke,
Physiol. Studien ; ' Sachs, Sot. 244.

CILIARY PROCESSES. See EYE.

CIL'IOPHRYS, Cienk.— A genus of
Actinophryina. C. infusionum, resembles
Act. sol, but is much smaller ; produces
swarm-germs ; in the scum of old infusions.
(Cienkowski, Schnitzels Arch. 1876, xii. 29.)

CIMEX, Linn. (Bug).— A genus of In-
sects, of the order Hemiptera, suborder
Heteroptera, and family Cimicidae.

Char. Antennae four-jointed ; labium
three-jointed, the basal joint the longest ;
thorax sublunate, not transversely divided ;
abdomen much depressed, and more or less
orbicular ; elytra reduced to a pair of short,
transverse, scale-like pieces ; wings none ;
legs moderately long and slender; tarsi
three-jointed.

C. lectidarius (the bed-bug). Ferruginous-
ochre ; thorax deeply emarginate, its sides
rerlexed; abdomen suborbiculate, acute at
the apex; third joint of antennas longer
than the fourth ; rostrum inflected beneath
the thorax ; labrum short, broad, subovate,
trigonate and ciliated.

The common bug has only three setae,
one stouter than the rest, and not toothed
or serrated (PL 33. fig. 27 a), and two others
extremely slender and very finely serrated
near the ends (PL 33. fig. 276) ; these are
about 1-20,000" in breadth at the serrated
portion (hence about the l-20th part of the
breadth of the lancets of the flea). The
female is larger and more elongated than
the male. The offensive odour is due to a
liquid secreted by a pyriform reddish gland,
situated in the centre of the metathorax,
and opening between the hind legs. The
eggs (PL 39. fig. 20) are white, elongate-
oval, elegantly pitted, and terminated by a
lid, which breaks off when the young
escape. The latter are very small, white
and transparent, and have a much broader
head, with shorter and thicker antennae
than the mature insect. They undergo four
moultings, and are eleven weeks in attain-
ing their full size.

C. columbarius (Bug of the pigeon).
Ferruginous-ochre ; thorax deeply emar-
ginate, sides reflexed ; abdomen orbicular,
subacute at the apex; third joint of an-
tennas slightly longer than the fourth ;
length about 1-5".

C. hinmdinis (Bug of the swallow).
Fusco-ferruginous ; thorax slightly emargi-
nate ; sides flat ; abdomen ovate, subacute
at apex; antennae short, third and fourth
joints nearly equal; length about 1-7".
Found in sw'allows' nests.

C. pipistrelli (Bug of the bat). Ferrugi-
nous-ochre, shining; thorax deeply emar-
ginate, sides slightly reflexed ; abdomen
ovate, posteriorly attenuate ; third joint of
antennae longer than the fourth ; length
1-6". On the common bat.

Me'gnin maintains that these all belong
to C. lectularius.

BIBL. De Geer, Mem. iii. ; Dumeril,

CINCHONINE.

[ 178 ]

CIRRIPEDIA.

Cons. gen. s. I. Ins. ; Westwood, Intr. ;
id. Brit. Cyd. N. H. i. 640 ; Jenyns, Ann.
A7. II. 1839, iii. 241 j Curtis, Brit. Entom.
xii. 569 ; Landois, Sieb. fy Soil. Zeitschr.
1868 (Anat.) (Qu. Mic. Jn. 1868, 268);
Megnin, Parasites, 1880, 53 j Leidy, Jn.
Mic. Soc. 1878, i. 27.

CIN'CHONINE. Cinchonine is insoluble
in ether. See ALKALOIDS.

BIBL. See CHEMISTRY.

CINCLID'lUM, Swartz.— A genus of
Mniaceee (operculate Mosses, arranged
among the Acrocarpi from prevailing habit);
of which one species, C. stygium, has been
found in Yorkshire.

BIBL. Wilson, Bryol. Brit. 260 ; Berke-
ley, Brit. Moss. 181.

CINCLIDOTUS, P. de B. See GUEM-

BELIA.

CINNAMON.— This consists of the inner
part of the bark of Cinnamomum Zeylani-
cum (Lauracese) ; that of Cassia (C. Cassia},
a coarser and less aromatic substance, is
often substituted. These both consist of
pitted 1-iber-cells andoil-bearingparenchyma
containing starch-granules, and are scarcely
distinguishable by the microscope. This
instrument, however, enables us to detect
the fraudulent extraction of the aromatic
oil, since heat applied for this purpose dis-
torts and destroys the characters of the
starch-granules. Ground Cinnamon and
Cassia are adulterated with flours of different
kinds, to increase bulk ; these are detected
by the characters of their starch-granules.
* BIBL. Hassall, Food $c. 399.

CIONIS'TES, S. T. Wright— A genus of
Hydroid Polypes, fam. Podocorynidse.

C. reticulata.

BIBL. Hincks, Brit. Zooph, 134 ; Wright,
Ann. N. H. 1861, viii. 123 (fig. 1).

CIRCULAR CRYSTALS.— This term
has been applied to the flattened groups
of radiating crystalline needles formed by
many salts and other crystalline substances.
The term, however, is objectionable as
tending to obscure their true nature. They
form beautiful polarizing objects. Among
the most interesting may be mentioned
boracic acid, oxalurate of ammonia, sali-
cine, and sulphate of cadmium. They
are further noticed under their respective
heads. Some of them are figured in PI. 39.
tigs. 9-12.

It is interesting to remark that some
of these circular crystals, as boracic acid,
although belonging to a biaxial system, yet
exhibit a single series of coloured rings.

See AMMONIA, OXALURATE OF, and PO-
LARIZATION.

BIBL. Brewster. Optics. 1853, 269.

CIRCULATION in ANIMALS. — The
movement in a temporarily or permanently
definite to-and-fro direction, of the nutritive
liquids of animals. We can only enumerate
here the articles in which will -be found a
notice of the circulation, whether true or
spurious, as occurring in the most easily
accessible or interesting organisms ; suffice
it to say that circulation is produced either
by the agency of muscular or other con-
tractile tissue, or by the action of cilia.
ASELLUS, ARACHNIDA, ENTOMOSTRACA,
INFUSORIA, INSECTS (COCCINELLA, EPHE-
MERA, LARVJE, LIBELLULID^:), RANA,
TRITON.

CIRCULATION in PLANTS. See RO-
TATION and LATEX.

CIRRIPE'DIA or CIRRIIOPODA.—
An order of Crustacea. The barnacles or
acorn-shells.

Char. Marine animals, in the adult state
attached to other bodies ; enclosed in a mul-
tivalved shell or in a coriaceous involucre
furnished with calcareous points, the rudi-
ments of a shell ; eyes none in the adult
state ; six pairs of legs, each with a short
fleshy peduncle, and two many -jointed
horny cirri ; mouth furnished with mem-
branoso-corneous mandibles and maxillae ;
tail terete, acuminate, reflexed between the
legs ; body not divided into segments,
although there are indications of them in
the form of transverse furrows on the dor-
sal surface. The six pairs of arms or legs
which are situated on the ventral surface
have each, supported on a short peduncle,
two long thin incurved filaments, consist-
ing of numerous joints, and covered with
hairs. The animals protrude these fila-
ments incessantly from the orifice of the
shell, and retract them, whereby water for
respiration and, with the water, food is
brought into the shell. Cirripeds are
usually hermaphrodite ; sometimes dioe-
cious.

The young1 Cirripeds, after leaving the
ovum, resemble some of the Entomostraca,
as Cyclops & Cypris (Nauplius-iorm) . They
are unattached, and possess eyes.

BIBL. Cuvier, Mem. Mus. d'Hist. Nat.
1815, ii. ; Saint- Ange, Mem. Cirrip. ; Cold-
stream, Todd's Cyclop,, art. Cirrhopoda ;
Burmeister, Rankenfusser ; J. V. Thompson,
Zool. Researches, and Phil Trans. 1835,
355 ; Darwin, Monoy. Cirripcdia (Ray So-

CLADINA.

CLADOPHORA.

ciety) ; Nicholson, Zool 1878, 271 j and the
Bibl. of ANIMAL KINGDOM.

CLADI'NA, Nyl.— A subgenus of Cla-
donia.

C. sylvatica, amaurocrcea, rangiferina,
and uncialis, with their varieties, occur in
Great Britain.

BIBL. Leighton, Lich.-Fl. G. B. 66.

CLADOBOT'RYUM, Nees. See DAC-

TYLIUM.

CLADO'DEL— A series of Lichens (fam.
Lichenacei), comprising the tribes Baeomy-
cei, Cladoniei, and Stereocaulei.

OLADO'DIUM, Brid.— A synonym of
some species of BRYUM.

CLADOGRAM'MA, Ehr.— A genus of
Diatom aceae.

Char. Frustules disk-shaped, valves con-
vex, with radiating irregularly forked lines ;
connecting-zone ring-like.

C. californicum, Ehr. (PI. 61. fig. 14).
C. conicutn, Grev. Barbadoes deposit.

BIBL. Ehrenberg, Mikrog. pi. 33; Gre-
ville, Mic. Trans. 1865, 97.

CLADO'MONAS, Stein.— A genus of
Flagellate Infusoria.

Char. Bodies ovate, with two equal an-
terior flagella, inserted in ends of a branched
tubular zoary.

C . fruticulosa, fresh water.

BIBL. Kent, In/us. 284.

CLADONE'MA, Duj.— A genus of Hy-
droid Polypes, fam. Stauridiidae.

C. radiation. Devonshire coast.

BIBL. Hincks, Brit. Zooph. 61 ; Gosse,
Dev. Coast, 257.

CLADONE'MA, Kt.— A genus of Fla-
gellate Infusoria.

Char. Bodies pyriform, oblique in front,
attached to a branched pedicle j flagella
] long and 1 short, lateral.

C. laxa. Fresh water ; on Myriophyllum.

BIBL. Kent, In/us. 264.

CLADO'NIA, Fee.— A genus of Liche-
naceous Lichens, with a somewhat shrubby
thallus, and fistular podetia, abundant on
moors and heaths. It comprises the sub-
genera Pycnothelia and Cladina. The Rein-
doer Moss (C. rangiferina) is common in
such localities. 26 other British species.

BIBL. Hook. Brit. Fl. ii. pt. 1. 238 ; Engl.
Sot. pi. 173, 174, &c. ; Leighton, Lich.-Fl.
G. B. 52.

CLADONIEI.— A tribe of Lichenaceous
Lichens, series Cladodei.

Gen. Cladonia and Pilophoron.

CLADOPH'ORA, Kiitz.— A genus of
Confervacese (Confervoid Algse), distin-

guished by the branched habit of the at-
tached filaments. The CladophorcB are in-
teresting in many respects, in particular for
the thick laminated structure of the cell-
wall, the special projecting orifice in this by
which the zoospores are discharged, the
large number of the zoospores, and, lastly,
by the favourable opportunity they afford
of observing cell-division in the growth of
the branched filaments. The filaments are
composed of cylindrical cells attached end
to end, from which the branches arise by
the gradual protrusion of a cylindrical pouch
near the upper end, which pouch, becoming
shut off by a septum, forms the first cell of
the branch. The cellulose wall acquires
repeated layers of thickening with age ; and
longitudinal and transverse striae may be
detected in these by careful management.
(See SPIRAL STRUCTURES.) The cellulose
wall is lined by a layer of protoplasm (pri-
mordial utricle), upon the inside of which
lies the chlorophyll, not, however, really
imbedded in it, as it is often seen retracted
from it in the centre of the cell. At certain
periods, numerous starch-granules occur in
the mass of chlorophyll ; but these disappear
when the latter is about to subdivide into
zoospores. When this takes place, the whole
mass of chlorophyll is contracted from the
wall, and becomes broken up, by a kind of
segmentation, into a very large number of
2- sometimes 4-ciliated zoospores (these
sometimes occur in pairs, through imperfect
division). The zoospores, which are pro-
duced in all the cells, are discharged through
a special papilliform orifice in the cell-Avail
(PL 9. fig. 13) ; they have a distinct red
spot. Numerous supposed species inhabit
fresh, brackish, or sea- water in Britain ;
some are very common and abundant ; but
it is difficult to draw out differential cha-
racters, as the habit appears to be very
variable. They are Confervce of older
authors.

C. glomerata, Dillw., is of a dark green
colour, and grows commonly in long drawn-
out skeins, in pure running water ; but it
seems to be identical with the rarer C. cega-
gropila, L., which forms dense balls 2 to 4"
in diameter, in lakes ; while there is also a
marine variety.

C. crispata, Sm., is perhaps not distinct j
it forms yellowish or dull green strata,
everywhere common in fresh water; fre-
quent in brackish water. It is the same as
C.flavescens, Roth. C.fracta, Fl. Dan., is
probably a form of this.

CLADOPHYTUM.

[ 180 ]

CLATI1ROCYSTIS.

The commonest marine species, which are
often found in large quantities on the sea-
shore, remarkable by their bright green tint,
are C. rupestris, L., Icetevirens, Dillw., al-
bida, Huds., lanosa, Roth, arcta, Dillw., and
glaucescens, Griff.; but some of these, and of
the rarer, appear doubtful. The species re-
quire a careful study of fresh specimens in
all stages. Kutzing (Sp. Alg.} has made an
inextricable mass of confusion of his species.
Rabenhorst admits 8 species, with nume-
rous varieties.

BIBL. Hassall, Alg. 213, pi. 65-67;
Harvey, Mar. Algce, 199, pi. 24 D ;
Thuret, Rech. sur les Zoosp. $c., Ann. Sc.
Nat. 3 se*r. vol. xiv. 10, pi. 16 ; Al. Braun,
Verjungung, Sfc. (Ray Soc. 1853); Mohl,
Vermischte Schnften, 362, pi. 13; Raben-
horst, Flor. Alg. 'iii. 333.

CLADOPH'YTUM, Leidy. — Probably
the mycelium of a fungus. Found in the
intestine of a lulus.

BIBL. See ARTHROMITUS.
CLADOSPO'RIUM, Link.— A genus of
Dematiei (Hyphomycetous Fungi), stated
by Tulasne to be conidiiferous forms of
Sphaeriacei. Cl. herbarum is one of the
commonest moulds ; it spreads over the
surface as a dense or loose web of con-
fluent tufts of microscopic filaments, straight
or curved, more or less varicose, simple or
branched ; from these arise chains of spores,
simple or with one or more septa, round,
oval, or longish according to age, and finally
becoming detached from one another.

Cl. herbarnm, Lk. Tufts effused, at first
green, then black ; spores olive ; very vari-
able in habit. Everywhere common on
decaying substances. Corda, Ic. Fung. iii.
pi. 1. fig. 24 ; Fresenius, Beitr. zur Myk.
pi. 3. fig. 29 ; Dematium articulatum, Sow-
erby, t. 400. fig. 8.

Cl. dendriticutn, Wallr. On leaves of
pear-trees and hawthorn. C. pyrvrum,
Berk. Gardn. Chron. 1848, 398. Helmin-
thosporium pyrorum, Desrnaz. No. 1051.
C. orbiculatum. Desm. Ann. Sc. Nat. 3 ser.
275.

Cl. depressum, Berk. & Br. On living
leaves of Angelica. Ann. N. H. 2 ser.
vii. 97, pi. 5. fig. 8.

Cl. brachormium, Berk. & Br. On leaves
of Fumitory. Ibid.

Cl. lignicolum, Corda. On dead wood.
Corda, Icon. Fung. i. pi. 3. fig. 206.

Cl. noduloswn, Corda. On stems of herbs.
Corda, Icon. Fung. i. pi. 4. fig. 212.
CLADOS'TEPIIUS, Ag.— A genus of

Ectocarpaceae (Fucoid Algae), containing
two common British species, C. verticillatus
and C. spongiosus, which grow on rocks and
stones, and form olive tufts a few inches
high, composed of rigid irregularly branched
cellular axes, clothed by whorls of short,
mostly simple, articulated branches. Harvey
states that the summer branches contain
dark grains in their withered tips, and are
deciduous, being replaced in winter by
others which bear numerous lateral stalked
spores. It is probable that these represent
respectively the trichosporangia and oospo-
rangia found in Ectocarpus, and that the
so-called 'spores' emit zoospores. See
ECTOCARPUS.

BIBL. Harvey, Br. Mar. Alg. pi. 9 A ;
Phyc. Brit. pi. 33 and 138.

CLADOT'RICHUM, Corda.— A genus of
Dematiei (Hyphomycetous Fungi), forming
dark flocculent points, or
confluent into powdery
strata, on dead stumps, &c.
The mycelium consists of
rigid, much-branched, sep-
tate filaments, the upper
joints swollen; the spores
in chains together at the
ends of branches, and bi-,
triseptate, constricted in
the middle.

The species are pro-
bably states of Ascomyce-
tous Fungi.

Cl. triseptatum, Berk,
and Broorne. Spores ob-
long, very obtuse, with
three septa, and constric-
ted opposite the middle
septum. Ann. Nat. Hist. ser. 2, vii. p. 98,
pi. 5. fig. 7. On a dead stump.

C. poiysporum, Corda (fig. 128). Spores
biseptate. Corda, Icon. Fung. iv. pi. 0. fig.
83 ; Prachtflora Eur. Schimmelbild. (Poly-
thrincium, Fries, Summ. Veg.}

CLATHROCYSTIS, Henfrey.— A ge-
nus of Palmellaceous Algae, founded en
Microcystis (Polycystis) ceruginosa of Kiitz-
ing. (PI. 5. fig. 9.) The plants occur in
autumn in myriads in freshwater ponds,
giving the water a rich grass-green tint;
the colour when dry is that of verdigris.
Their appearance to the naked eye is that
of a mass of green granules suspended in a
colourless liquid. Under the microscope
each granule is found to be a gelatinous
body 1-50 to 1-15" in diameter, in which
are imbedded an infinite number of green

Cladotrichum

polysporum.

Magn. 200 diam.

CLATHRULIXA.

[ 181 j

CLAVICEPS.

cells about 1-8000" in diameter. The gela-
tinous masses expand by the multiplication
of the green cells in the peripheral stratum,
so that they become hollow sacs, the walls
of which burst at various points and" pro-
duce a clathrate structure. The processes
of the network ultimately break asunder
and commence a new development of the
same kind.

BIBL. Henfrey, Mic. Trans, new ser. iv.
53, pi. 4. figs. 28-36; Currey, Mic. Jn.
vi. 215 ; Kiitz. Tab. Phyc. i. pi. 8 ; Duncan,
Jn. Mic. Soc. 1880, iii. 17.

CLATHRULINA, Cien.— A genus of
Ac tinophryina= a stalked Actinophrys con-
tained in a f enestrated globular or pyriform
carapace. The pseudopodia project through
the fenestrse.

2 species or varieties.

BIBL. Cienkowski, Archiv f. mik. Anat,
iii. p. 311 ; Qu. Mic. Jn. 1868, p. 31.

CLATHRUS, Mich.— A genus of Gaste-
romycetous Fungi, fam. Phalloidei.

C. cancellatus, fig. 273.

CLAVA, Gm. — A genus of marine Hy-
droid Polypes, fam. Clayidse.

6 British species j height | to 1-J-".

C. multicornis. Rose-coloured, mouth
white ; 1|'' high. Common on stones be-
tween tide-marks.

BIBL. Hincks, Brit. Zooph. p. 1.

CLAVATELLA, Hincks.— A genus of
Hydroid Polypes, fam. Clavatellidae.

C. prolifera, British.

BIBL. Hincks, Brit. Zooph. 70.

CLAVATELL1ILE.— A family of Hy-
droid Polypes. 1 genus, Clavatella.

BIBL. Hincks, Brit. Zooph. 69.

CLAVA'TI. — A family of Hynaenomyce-
tous Fungi, characterized by bearing basi-
diospores covering the tip and sides of
branched or simple club-shaped or variously
cylindrical, compressed, or foliaceous re-
ceptacles. See BASIDIOSPOBES, HYMENO-
HYCETES.

CLAVELI'NA, Sav.— A genus of Tuni-
cate Mollusca, of the family Clavelim'dae,
under which head the characters are given.

C. lepadiformis. Thorax a third of the
length of the body, lines yellow; lergth
^ to f". On rocks and stones at low water.

C. -producta. — Thorax very short, as broad
as long, abdomen very long.

C. pumilio. Nearly sessile and square.

BIBL. That of the family.

CLAVELI'NID^E.— A family of Tuni-
cate Mollusca.

Distinguished by the separate bodies

arising from a common creeping root-like
fibre, and the mantle being united to the
test at the orifices only.

These animals are very transparent, and
well calculated for the study of the internal
structure of the order. Genera :

Clavelina. Bodies oblong, erect ; bran-
chial and anal orifices without rays j thorax
marked with coloured lines.

Perophora. Bodies roundish, compressed ;
thorax not marked with coloured lines.

BIBL. Forbes and Il^nlzy, Brit. Mollusca,
i. 25 ; Goose, Mar. Zool. i. 135 ; Lister, Phil.
Trans. 1834 ; M. -Edwards, Ascid. Comp.

CLA'VIPES, Tulasne. — A genus of
Sphaeriacei (Ascomycetous Fungi), con-
taining the plants which produce the ergot
of rye and other grasses. These plants have
recently been extricated from great confu-
sion by Tulasue, who appears to have placed
their history on a satisfactory basis.

The first sign of the attack upon the
flower of a grass is the appearance of a
white mould, sometimes accompanied by a
honey-like secretion, consisting of minute
cells, somewhat after the fashion of the
yeast-plant; a swelling (sphacelid) then
takes place upon the outside of the nascent
pistil, which extends to the outer part of
the substance of the wall of the ovary,
growing with this until it forms a fungoid
mass of the same shape as an ovary, but
obliterating the cavity of the latter. At
this time it is soft, white, grooved on the
surface, and excavated by irregular cavities,
which are connected with the external folds
or grooves ; the surfaces of these are all
covered with parallel linear cells, like an hy-
rnenium ; and from the extremities of these
arise elongated ellipsoid or oval cells, about
1-5000' ' in length. These become detached,
and, when they are placed in water, germi-
nate and emit "filaments. These bodies are
spermatia, stylospores, or perhaps conidia :
they exhibit no motion in water, although
they resemble the spermatia of some other
fungi. At this time Tulasne calls the struc-
ture a spermogonium. At a certain epoch a
viscid fluid exudes from the sphacelia, flow-
ing over it and carrying about multitudes
of the spermatia or stylospores (PL 26. tig.
17) ; but previously to this, a solid body, of
a violet colour on the surface and white
within, has originated at the base of the
spermogonium, and it gradually grows and
rises out of the paleae of the flowers, form-
ing the spur or ergot. This is not a meta-
morphosed seed, resulting from diseased

CLAVID.E.

[ 182 ]

CLIMACONEIS.

conditions, but a real new fungoid structure,
the Sclerotium of DC. and others. When
this ergot is sown in the earth like a seed,
it produces a number of little pedicles sur-
mounted by thickened heads, repesenting
stalked Sphcerice (PI. 26. fig. 18) ; and on
these heads are ultimately found fine points,
which indicate the ostioles of little concep-
tacles (fig. 19). The walls of these concep-
tacles are lined with asci of elongate clavate
form (figs. 20, 21), with linear, slightly
clavate paraphyses. These bodies are the
Sphceria purpurea of Fries, System. Myc.

Our space does not admit of further de-
tails ; but it must be noted that very varied
opinions have hitherto prevailed as to the
nature of Ergot. Smith and E. Quekett,
as also Leveille', Phoebus, Mougeot, and
F«5e, regarded the ergot as a mere diseased
form of the seed, associated with a parasitic
Fungus (Sphacelia, Le>., Fe"e ; JErgotcetia,
Quekett).

The sphacelia is often accompanied by a
Mucedinous fungus, which is certainly not
the result of germination of the stylospores
as might be imagined, but a distinct plant.

Tulasne describes three species :

C. purpurea, Tul. (PI. 26. figs. 18-22).
The ergot of grasses = Sphceria entomor-
rhiza, Schum. ; Sphceria (Cordyceps) pur-
purea, Fries ; Kentrosporium mitratum,
Wallr. ; Sphceropus fungorum, Guibourt :
Cordyliceps purpurea, Tulasne. On the
flowers of Grasses, such as rye, wheat, oats,
and numerous pasture grasses.

C. microcephala, Tul. Kentrosporium
microcephalum Wallr. ; Sphceria microce-
phala, Wallr. ; Sphceria acus, Trog. ; Cordy-
ceps purpurea, var. acus, Desm. On Phrag-
mites communis and Molinia ccerulea.

C. nigricans, Tul. On species of Scirpus.

BIBL. Tulasne, Ann. des Sc. Nat. 3 ser.
xx. 5-43, pis. 1-4, where all the previous
literature is reviewed ; Quekett, Linn. Tr.
1839; Cesati,.B0*. Zeit. 1855, 74; Currey,
Qn. Mic. Jn. 132; Bonorden, Sot. Zeit.
1858, 97 ; Lindley, Veg. Kingd. j Kiihn,
Mitt, landw. Inst Halle, i. 1863 ; Sachs,
Sot. 381.

CLA'VnLE.— A family of Hydroid
Polypes.

Char. Polypes claviform or fusiform, with
scattered tentacula. Genera :

Polypes stalked.

Stem simple Tubiclava.

Stem much branched Cordylophora.

Polypes sessile.

Tentacles few Turris.

Tentacles very numerous ... Clava.'

BIBL. Hincks, Hydr. Zooph. p. 1.

CLAVULA'RIA, Grev.— A genus of
Diatomaceae.

Char. Frustules free, linear, with nu-
merous transverse pseudo-dissepiments, in-
terrupted by a central smooth external
plate. Valves with a central inflation, and
a longitudinal row of short subcapitate
processes.

C. barbadensis (PI. 51. fig. 33). In Bar-
badoes deposit.

BIBL. Greville, Micr. Trans. 1865, p. 24.

CLAVULI'NA, D'Orb. — A modified
Valvulina, in which the triserial arrange-
ment of the chambers (three in one whorl
of the spire) has passed into a uniserial or
linear row, making altogether a claviform
shell.

The long dimorphous Textularice, having
a similar shape, have been recorded as Cla-
vulince ; but the absence of the septal valve
distinguishes them.

C. parisiensis (PI. 23. fig. 51.) is a neat
form, with a marked distinction of triserial
and uniserial growth. These long dimor-
phous Valvulince are common in some
Tertiary deposits, and in the Indian and
Australian seas.

BIBL. Parker and Jones, Ann. N. H.
ser. 3, v. 467-469; Carpenter, For. 147.
193.

CLEISTOCAR'PI, (Closed-fruited, f. e.
inoperculate). — An artiticial division of the
Mosses.

In this group, the capsule bursts irregu-
larly. It contains the families Bruchiaceae,
Phascaceae, and Ephemereae.

See MOSSES.

CLETO'DES, Brady.— A genus of Cope-
poda (Entomostraca). 4 species. In dredg-
ings on the north British coasts.

BIBL. Brady, Copepoda (Ray Soc.).

CLIMAC AM'MINA, Brady.— An arena-
ceous, coarse Textularian Foraminifer, of
bigenerine growth ; with labyrinthic struc-
ture inside the chambers, and cribriform
aperture. Fossil in the Mountain-limestone
of Britain and Russia ; not rare.

BIBL. H. B. Brady, Monog. Carb. Foram.,
Pal Soc. 1876, 67.

CLIMA'CIUM, W. and Mohr.— A genus
of Mosses, synonymous with Hypnum (den-
droides).

BIBL. Wilson, Bryol.Brit. p. 325 ; Berke-
ley, Srit. Moss. p. 140.

CLIMACONE'IS, Grun.— A genus of
Diatomaceaa.

Char. Frustules bacillar, free (?), with

CLBIACOSPHENIA.

[ 183 ]

CLOSTERIUM.

'2 scalariform dissepiments ; valves striato-
punctate, coslae none.

C. Lorenzii. Valves linear-lanceolate,
swollen at the ends and the middle. In the
Adriatic.

BIBL. Grunow, Wien. Verhandl. 1862,
421, pi. 8. fig. 7.

OLIMAOOSPHE'NIA, Ehr.— A genus
of Diatomacese.

Char. Frustules cuneate, stipitate, di-
vided into loculi by transverse septa ; valves
obovato-lanceolate, with moniliform vittae
in the front view. Marine ; not British.

C. australis. Very shortly stipitate ; sides
of the valves not (very faintly?) striated.

On Algae from New Holland and South
Africa.

C. moniligera (PL 25. tig. 9). Stipitate,
sides of the valves transversely striated («,
front view ; 6, side view).

In the Gulf of Mexico.

Rabenhorst enumerates 6 species.

BIBL. Ehrenb. Abh. Berl. Ak. 1841, 401 :
id. Ber. 1843 ; Kiitzing, Badllar. 123, and
Sp.Alg. 114; Rabenhorst, Alg. i. 299.

CLIMACOS'TOMUM, Stein, = Spirosto-
mum virens, Ehr.

CLI'ONA, Grant. — A genus of marine
Sponges. By means of the spicula imbedded
in their surface, they burrow into rocks,
shells, and stones.

BIBL. Gosse, Mar. Zool. i. 5 ; Hancock,
Ann. Nat. Hist. 1849, i. 321 ; Bowel-bank,
Brit. Spog. ii. p. 212.

CLONOS'TACH YS, Corda.— Agenus of
Mucedines (Hyphomycetous Fungi), appa-
rently not distinct from BOTRYTIS.

C. araucaria (fig. 347) has been found in
England.

BIBL. Corda, Prachtft. europ. Schimmel-
Uld. pi. 15 ; Currey, Qu. Mic. Jn. v. 126.

CLOSTE'RIUM, Nitzsch.— A genus of
Desmidiaceae (Confervoid Algae).

Char. Cells single, elongated, attenuated
towards each end, entire ; mostly curved
Innately or arcuate ; junction of the seg-
ments marked by a pale transverse band.
Eudochrome green.

This beautiful genus is of great interest to
the scientific microscopic observer. Many
of the species are very common, so that
scarcely a drop can be taken from the bot-
tom of a clear pool without some of them
being contained in it.

Each cell is composed of two equal por-
tions, uniting at a transverse line occupying
the middle of the cell. The endochrome
exhibits longitudinal bands (PL 14. fig. 40),

the number varying in different species, of
a darker green than the rest of the endo-
chrome (PL 14. figs. 40, 41, 43). A num-
ber of chlorophyll-vesicles are frequently
visible in the endochrome, sometimes scat-
tered irregularly, at others arranged in lon-
gitudinal series (PL 14. fig. 43) ; at certain
periods these contain starch-granules.

The green endochrome is separated from
the cell-wall by a stratum of colourless pro-
toplasm which occupies a bluntly triangular
space at each extremity. In many cases
the protoplasm at these ends exhibits a
large roundish vacuole, in which a number
of minute granules are contained, often in
active motion. Similar granules are visible
in the marginal line of protoplasm, which
exhibits a distinct circulation, requiring a
power of about 400 to show it clearly.
Focke, Osborne, and others have described
cilia inside the cell-wall, and attributed the
circulation to their action ; but this is erro-
neous. The protoplasm appears to flow up
over the interior of the cell-wall on all
sides, from the centre to the extremity,
then to turn round past the vacuole, and
return over the surface of the green endo-
chrome parallel to the upward course.
Wills states that the vacuoles at the ends
of the cells are contractile vesicles, con-
nected with the flow of the currents.

The Closteria are reproduced in various
ways. The individuals divide, like the re&t
of the Desmidiaceae, the separation taking
place transversely in the situation of the
transparent space, where two new half-cells
become developed, subsequently separating.
As these new ' halves ' are often very small
at the epoch of separation, specimens occur
with the two portions very unequal.

Another mode of reproduction is by con-
jugation. In this, a pair of individuals be-
come united somewhat in the same way as
in the Zygnemaceae ; ordinarily the indi-
viduals conjugate by the convex side. The
process is this : — The outer membranes of
the parents split circularly in the situation
of the central transverse space ; a delicate
internal membrane is protruded from each
as a sac, and these meet and coalesce.
Sometimes the sacs are in pairs from each
parent-cell. (See CONJUGATION.) When
the cross process is complete, the contents
of both parent-cells pass into it and become
collected into a globular or squarish cell or
zygospore (PL 14. figs. 42 & 46.). Dif-
ferent statements are made with regard
to the ultimate history of this; and it is

CLOSTERIUM.

[ 184 ]

CLOSTERIUM.

probably variable. Morren states that it
becomes a moving gonidium, while most
authors state that it becomes a resting-spore
with firm membranous coats. Again, Mor-
ren assumes the segmentation of the green
contents of this spore or gonidium into a
number of portions, each of which becomes
a perfect individual. Focke gives a figure
which seems to bear out this statement ;
and it would find an analogy in the mode
of reproduction by active gonidia in Pedi-
astrwn, described by Caspary and Brauu.
(See PEDIASTRUM.) Focke also figures a
condition of Closterium Lunida, in which the
whole of the green contents of an individual
cell had become retracted from the walls,
and converted into a number of green glo-
bular bodies, with proper coats, resembling
the resting spores found under certain con-
ditions in many filamentous Algoe. (See
(EDOGONIUM and SPIROGYRA.)

The Closteria are capable of fixing them-
selves by one extremity to foreign bodies,
and Ehrenberg asserted the existence of a
foot-like organ ; but no such structure seems
to exist. The individuals also possess a
power of moving in water, but the nature
of this is inexplicable at present. The seg-
ments of the outer membrane separate from
each other when their contents decay, and
often when they are dried. The membrane is
coloured blue by sulphuric acid and iodine
(cellulose) ; in its natural condition it often
has a reddish tint, especially towards the
ends.

Rabenhorst describes 52 species, with
numerous varieties.

Analysis of ordinary British species : —

i Cell suddenly narrowed at the ends j attenuatum,
1. < into a conical point .................. ( 1.1-57".

( Cell not suddenly narrowed ......... 2

'"Cell striated, tapering into a beak
at ends, lower margin prominent
atmiddle .............................. 3

2 i Cell very minute, beaked, straight, (Grifflthii*,
"' not striated, nor lower margin } 1. 1-3 00 to
prominent at middle ............... ( 1-450".

Cell not beaked ; if striated, lower

margin not prominent at middle 6
I Beaks setaceous, as long as or lon-
o ) ger than body ........................ 4

' } Beaks linear, much shorter than
( body

< Beaks much longer than body ...... {

( Beaks about as long as body ...... -| f^?

Cells much inflated at middle, j Xalfsii,
rapidly tapering at ends ............ ( 1.1-79".

Cells slightly inflated at middle, j lineatum,
gradually tapering at ends ...... \ 1.1-48".

* PI. 14. figs. 57 & 58.

t PI. 14. flga. 45 & 46 (Conjugation).

{Cell minute, acicular; sporangium
cruciform 1
Cell not acicular; sporangium or-
bicular 8

, (End. obtuse JT&HO-.

I Ends acute JTwjJ".

/Cell semilunate or semilanceolate,
lower margin inclined upwards

8.^ at ends 9

Cell with either truncate ends, or
lower margin inclined down-
* wards at ends 12

9 J Vesicles numerous, scattered -J

' Vesicles in a longitudinal row

C Cell linear-lanceolate ; ends coni- ( acerosum t,
HJ cal, obtuse ..................... ... ...... \ 1. 1-70 to 1-58".

} Cell semilanceolate ; ends sub- j l-anceolalwn,

; acute .................................... f 1.1-64".

j Cell not striated, crescent-shaped 13
12- •< Cell either not crescent-shaped, or

( else distinctly striated ............ 17

j" Vesicles numerous, scattered ...... \E\re^b^?ii'

13.^ Vesicles in longitudinal row ......... 14

(^ Empty cell colourless, endsround-

14. Empty cell usually reddish, ends

subacate ................................. 16

( Lower margin of cell inflated at ( moniliferuml,
15 J middle .................................... } 1. 1-75 to 1-60".

Cell not inflated at middle

> ...............

^Cell slender, not inflated at middle]

/Lower margin of cell inclined up- i ,. j

wards at truncate ends ; lougitu- ) d^ymotocum §,
17.-J dinal striae none or indistinct ... | L L"6& •

Ends of cell inclined downwards ;
{ striae distinct ........................... i&

,„ ( Longitudinal stria? 3 to 7,prominent 19
( Longitudinal striae numerous, fine 20

lit.

i Cell semiluna or crescent-shaped -j coi um>

1. 1-75".

I Cell linear ,

(Cell narrowly linear, nearly (juncidum,

20. •> straight { 1-69 to 1-111".

( Cell tapering, curved 21

/Longitudinal striae crowded, su- j striolatum,

2. ! tureslto3 \ 1. 1-80 to 1-68".

j Longitudinal striae not crowded I intermedium,
(. sutures usually more than 3 ( 1. 1-77 to 1-54".

BIBL. Meneghini, Syn. Desmid.,Linna>af
xiv. 201 j Ehrenb. Infus. ; Ralfs, Brit.
Desmidiece ; Smith, Ann. N. H. 1850, v. 1 ;
Brebisson, Alg. Falaise, fy Conjugates ; Kiit-
zing, Spec. Alg. 163 ; Berkeley, Ann. N. H.
2 ser. xiii. 256; Braun, Itejuv. (Ray Soc.
1853, 289, 292) ; Morren, 'Ann. Sc. Nat.
2 s<§r. v. 257 ; Focke, Physiol. Stud. 1847 ;
Osborne, Qu. Hie. Jn. iii. 54 ; Henfrey,

* PL 14. fig. 40.

t PI. 14. figs. 41 & 42 (Conjugation).

I PI. 14. fig. 43.

$ PI. 14. fig. 44.

CLYPEASTER.

[ 135 ]

COAL.

Ann. N. H. 3 ser. i. 419 ; Pritchard, Infus.
746; Kabenhorst, J'for. Aly. iii. 123 j Wills,
Jn. Mic. Soc. 1880, iii. 845.

CLYPEAS'TER, Lamk.— A genus of
Echinodermata.

The hairs or spines springing from the
shell are beautiful microscopic objects.

CLY'TIA, Lam.— A genus of Hydroid
Polypes, fam. Campanulariidae.

1 Brit, species : C. Johnstoni= Campanu-
laria volubilis.

BIBL. Hincks, Hyd. Zooph. p. 140.

CNEMIDA'RIA, Presl.— A genus of
CyatheaB (Polypodiaceous Ferns). Now
consolidated with HEMITELIA.

Fig. 129.

Fig. 130.

Fig. 131.

Fig. 132.

C. (Hemitelia) horrida.

Fig. 129. Fragment of a pinnule, the sori covered by
indusia. Magnified 5 diameters.

Fig. 130. A scrus with indusium destroyed.

Fig. 131. The same, side view, showing the fragment
of the indusium at the base.

Fig. 132. Vertical section of a sorus.

Figs. 130-132 magnified 25 diameters.

COAL. — This substance, although classed
from its mode of occurrence in nature in the
mineral kingdom, is in all cases of vegetable
origin. The degree, however, in which
traces of organic structure may be detected
in it varies extremely. Coal may be either
tolerably pure, containing but slight admix-
ture of earthy matters, or it may contain
large quantities of earthy substance, and
pass gradually into a carbonaceous impreg-
nation of an earthy basis, as in the various
modifications of bituminous shales. In the

next place the degree of metamorphosis of
the vegetable matter may be equally varied,
so that we have it still retaining its struc-
ture very evidently, as in lignites, &c., or
with the structure greatly destroyed, or
altogether lost, as in much ordinary coal and
anthracite, which however are apparently
of somewhat different origin from the more
recent lignites. Some of the old coal-beds
appear to have been formed from deposits
analogous to our peat-bogs, and hence na-
turally consist in great part of vegetables
whose remains soon become undistinguish-
able ; but that arborescent vegetation was
also present and contributed to form the coal,
is proved by the detection of woody structure
somewhat like that of the Coniferse in certain
specimens of coal. Sometimes the woody
structure is even evident to the naked eye,
in a charcoal-like appearance of the frac-
tured surface or bed-planes of coal. In many
lignites the coal consists of trunks of trees
converted into coal without much alteration
of the appearance of texture of the wood ;
and in these the structure is very readily
made out by means of the microscope.
Some old coal is largely or entirely composed
of sporangia of Lycopodiaceous or Lepido-
dendroid plants, cemented together by a
brown substance derived from the decom-
position of the tissues of the coal-forming
plants. It would be out of place here to
enter upon the geological and chemical
questions connected with coal; the object
of applying the microscope to it is to ascer-
tain the existence or absence of organic
structure. For this purpose various meth ods
are employed. That most in use is the
preparation of exceedingly thin slices in the
manner usually adopted for fossil structures,
but the brittle and opaque character of
coal opposes great difficulties here. Traces
of structure may be made out in some
cases by grinding coal to fine powder and
examining the fragments ; but this plan is
very unsatisfactory. A third method is to
burn the coal to a white ash, and examine
this under the microscope : it often exhibits
perfect skeletons of vegetable cells, but these
are very fragile, and require great care in
their management. By imbuing them very
cautiously with turpentine and Canada bal-
sam, and placing on the covering glass when
the latter has become rather firm, permanent
preparations may of ten be obtained. Schulze
recommends boiling in nitric acid before
incinerating the coal. The method which
has been attended with most success in our

COB^A.

[ 180 ]

COCCOCHLOPJS.

hands is as follows. The coal is macerated
for about a week in a solution of carbonate
of potash; at the end of that time it is
possible to cut tolerably thin slices with a
razor. These slices are then placed in a
watch-glass with strong nitric acid, covered
and gently heated ; they soon turn brownish,
then yellow, when the process must be ar-
rested by dropping the whole into a saucer
of cold water, or else the coal would be
dissolved. The slices thus treated appear
of a darkish amber colour, very transparent,
and exhibit the structure, when existing,
most clearly. We have obtained longitu-
dinal and transverse sections of Coniferous
wood from various coals in this way ; al-
though this structure is most abundant in
lignites. The specimens are best preserved
in glycerine, in cells ; for spirit renders them
opaque, and even Canada balsam has the
same defect. Schulze states that he has
produced the cellulose reaction with iodine,
in coal treated with nitric acid and chlorate
of potash.

The proper identification of vegetable
structures in coal must of course depend
upon a sufficient knowledge of the charac-
ters of vegetable tissues and organisms being
possessed by the observer.

BIBL. Witham, Fossil Vegetables, Ediub.
1833 j Link, Abh. Berl. Akad. 1838 ; 34 ;
Goppert, Preisschrift ub. Steinkohle.n, Leiden,
1848; Lindley and Hutton, Fossil Fl.;
Schleiden and Schmidt, Geognost. Verlidltn.
des Saalthales, Leipzig, 1846 j Ehrenberg
and Schulze, Berlin Ber. 1844; F. Schulze,
ibid. 1855 ; Ann. N. H. xvi. p. 69 ; Bailey
(Anthracite}, Ann. N. H. xviii. 67; Unger,
Gen. et Spec. Plant. Foss. 1850 ; Oarruthers,
Mn.Mic. Jn. ii. 377, 225, iii. 144; Wil-
liamson, ibid. ii. 66 ; Lyell, Princip. of Geol.;
Huxley, Contemp. Rev. 1867; Dawson,
Acadian Geol 1868 ; Mn. Mic. Jn. 1870,
319; Williamson, Phil. Proc. $ Trans.
1873 et seq. ; Zirkel, Mineral**, 1873, 257 j
Reinsch, SteinkoMe, 1881.

COB^E'A, Cuv. — A climbing Dicotyledo-
nous plant, of the Nat. Order Polemomacese,
common in cultivation, remarkable for the
curious pyriform cells upon its seeds, con-
taining a spiral fibre (PL 28. fig. 20). See
SPIRAL STRUCTURES.

COCCID'IUM.— A form of fructification
in the FLORTDEJE.

COCCINEL'LA, Linn. (Lady-bird).— A
genus of Insects, of the order Coleoptera,
and family Coccinellidse.

C. septenipunctata} the common lady-bird.

This insect exhibits the circulation through
the elytra. If one of these is separated
from the body without being detached, and
arranged in such a manner that it may be
viewed as a transparent object, slow and
uniform continuous currents, one ascending
and the other descending, will be seen be-
tween the lamina of which the elytrum
consists. On dividing the latter an amber
transparent liquid containing colour] ess glo-
bules escapes.

BIBL. Nicolet, Ann. Sc. Nat. 3 s6r. vii. ;
Westwood, Introd. fyc. : Curtis, Brit. Ent.
208 ; Stephens, Brit. Entom. ; Calver, Ka-
ferbuch, 690.

COCCOBACTE'RIA ..— A term employed
byBillroth to designate the Schizomycetous
Bacteria and their allies. The author re-
gards the globular forms Coccos, and the
rod-like forms Bacterium and Bacillus, as
belonging to a single organism ; the former
arising from the division and spore-formation
of the latter, and the two forms being often
found in the same filament or zooglcea-form ;
the whole constituting his Coccobacteria
septica. Billroth gives new names to the
various forms, and regards them as colour-
less parallel states of many of the lower
Algae. The occurrence of these organisms
in various liquids, and their influence in the
production of decomposition and disease,
are fully treated in his elaborate and well-
illustrated treatise. (Billroth, Coccobacteria
septica, 1874.)

COCCOCAR'PE^E (Algse). See CRYP-

TONEMIACE^J.

COCCOCAR'PIA, Pers.— A small genus
of mostly tropical Lichens, now united with
Pannaria.

C. (P.) plumbea, Lightf., is British, and
has the thallus orbicular, livido-cinerascent,
adnate ; apothecia reddish-brown ; spores 8,
simple.

BIBL. Lightfoot, Fl. Scot. ii. 826, pi. 26 j
Leighton, Lich-FL G. B. 154.

COCCOCHLO'RIS, Sprengel (Palmo-
glcea, Kiitz). — A genus of Palmellaceee
(Confervoid Algse), consisting of green mi-
croscopic cells, oval or globular, imbedded
in a gelatinous matrix, which is at first de-
finite in form (thus differing from Palmella},
subsequently effused and shapeless. The
green cells are vesicles, filled with granular
colouring-matter (chlorophyll) when in
active vegetation. They multiply by divi-
sion ; and besides this, some of them grow
much larger than the rest, and their con-
tents are converted into a number of cells ;

COCCOLITHE.

L 187 j

COCCONEIS.

these large cells become free from the gene-
ral frond, and lav the foundation of new
ones, originally of definite form, which in-
crease in size by the division of the indivi-
duals within a persistent gelatinous invest-
ment. Brebisson, Ralfs, and Braun describe
a process of conjugation in C. BreUssonii
(PL 7. fig. 6). Two cells come into contact,
and their membranes become fused ; the
intermingled contents then undergo a meta-
morphosis, brownish oil-globules replacing
the chlorophyll ; and the ' spore-cell ' thus
produced passes through a period of rest
before resuming its vegetative development.
Thwaites states that the slender filamentous
bodies sometimes found in the frond are
part of the organization of the plant (see
PALMELLACEJE). Several British species
are described :

C. protuberans, Spreng. Frond green,
irregularly lobed, spreading on the ground,
cells elliptical, about 1-3000", enlarged vesi-
cles 1-500 to 1-1000". Hassall, Alga, pi. 76.
fig. 7, pi. 82. figs. 6-10 ; Palmella protube-
rans, Grev. Sc. Crypt, Fl. pi. 243. fig. 1.

C. muscicola, Meneghini. Hassall, /. c.
pi. 78. tigs. 3 a, 3 b.

C. hycilina, Menegh. Fresh water. Hass.
/. c. pi. 78. figs. 2 a, 2 b.

C. depressa, Menegh. Hass. 1. c. pi. 78.
figs. 4 a, 4 b.

C. Mooreana. Hass. 1. c. pi. 78. 1 a, 1 b.

C. riwlaris. Hass. /. c. pi. 78. 6 a b.

C. Grevillei, Hass. Frond minute, dense-
ly crowded, globose or somewhat lobed,
green. In healthy moist situations, fre-
quent. Hass. /. c. pi. 78. tigs. 7 a b and 8 ;
Palmella brotryoides, Grev. Sc. Crypt. Fl.
pi. 243. fig. 2.

The plants are not yet satisfactorily un-
derstood ; the relations to Palmella and
Glceocapsa are confused.

BIBL. Meneghini, Monogr. Nostoch. ;
Kiitzing, Phyc. gen. ; Braun, Rejuv. (Ray
Soc. 1853), as Palmoglcea ; Thwaites, Aim.
N. H. ser. 2, vol. ii. 312 (as Palmella) ;
Nageli, Einzell. Algen, 1849 ; Rabenhorst,
Fl. Alg. ii. 67.

COC'COLITHE or COCCOLITE.— A
term applied to the granular varieties of
pyroxene (native silicate of magnesia, with
metallic silicates).

COC'COLITHS.— The name given by
Huxley in 18u8, to minute oval or round,
calcareous bodies (PL 23. fig. 56 b), 1-900"
aiid less in size, abounding in the Atlantic
ooze, either loose or attached to small lumps
of protoplasm (' Coccospheres,' Wallich).

Two forms were recognized, Discolithi and
Cyatholithi. Similar microliths had been
noticed as forming a large proportion of
white chalk by Ehrenberg, Reade, and
Sorby. Wallich also found them in the
North Atlantic, in chalk, in tropical float-
ing Coccospheres, and in dredgings in the
English Channel. Haeckel subsequently
found them in the harbour of Lanzarote,
Carter in the English Channel, and Guem-
bel in limestones of all ages.

Ehrenberg termed these little bodies
' Morpholites of the chalk,' and regarded
them, like his l crystalloids,' as due to the
rearrangement of calcareous particles. Sor-
by, Huxley, Wallich, and Haeckel differ in
opinion as to whether they exist indepen-
dently or not of Coccospheres. Carter
ascribes them to an Alga (Melobesid).

Coccoliths of either kind, treated with,
dilute acid, leave a soft flexible cast or film,
which is coloured yellow by iodine, pale
red with carmine, red by Millon's test, and
is dissolved by alkalies.

BIBL. Ehrenberg, Monatsber. Ak. Berlin,
1836 ; Pogg. Ann. 1836, xxxix. 101 ; Ab-
handl. Ak. Berlin, 1838, 67 ; N. Jahrb. f.
Min. 1840, 680; Journ. prakt. Chemie, 1840,
xxi. 95 ; Edin. N. Phil. Journ. 1841, xxx.
353 ; Mikrogeologie, 1854 ; Reade, ManteWs
Wonders of Geology, 7th ed. ii. 953 ; Huxley,
Deep-sea Soundings, fyc. 1858, 64 ; Qu. Mic.
Journ. 1868, 203 ; Wallich, Life at Great
Depths, 1860, 13 ; Ann. Nat. Hist. 1861,
vii. 396, ibid. viii. 52 ; Sorby, Proc. Lit.
Phil. Soc. Sheffield, 1860 ; Ann. N. H. Sept.
1861 ; Haeckel, Jen. Zeitschr. v. 1870 ;
Guembel, Jahrb. Munch. 1870, 753 j Carter,
Ann. N. H. 1871, vii. 184.

COCCONETS, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, depressed, adnate;
valves elliptical, one of them with a median
line and central nodule.

The valves are mostly covered with dots
(minute depressions), appearing like lines
under a low power.

The upper valve differs from the adnate
one in not being furnished with the central
nodule : under a low power it appears to
have a median line as well as the adnate
valve ; but this, in some at least, arises from
the dots or markings at this part being more
closely in contact than elsewhere.

The frustules are often found densely in-
crusting filamentous Algae.

C. pediculus (PL 16. fig. 17). Frustules
very slightly arched (front view) ; valves

COCOONEMA.

[ 188 ]

COCOA.

elliptical, striae longitudinal, faint j length
1-1200 to 1-700" j aquatic.

C. placentula. Frustules flat j valves el-
liptical ; striae longitudinal, faint ; length
1-760" ; fresh water, common.

C. scutellum (PL 16. fig. 18). Frustules
dorsally convex; valves ovato-elliptical,
striae transverse or slightly curved ; length
1-700" ; marine. /3. Nodule dilated into a
stauros.

C. Thwaitesii (Achnanthidium flexellum,
Brebiss., Kiitz.). Ends of valves slightly
produced ; fresh water, length 1-900".

C. Grevillii. Oval, with transverse cana-
liculi ; marine.

C. diaphana. Elliptical, diaphanous;
marine.

Rabenhorst describes 37 European spe-
cies, with numerous varieties; and enu-
merates 37 foreign species (with the re-
ferences).

BIBL. Ehrenb. In/us. ; Kiitzing, BacilL,
and Sp. Alff. 50 ; Smith, Brit. Diat. i. 21 j
Rabenhorst, Flor. Alff. i. 98; GreviUe,
Micr. Tr. 1864, 9, 1865, 33, 1866, 126.

COCCONE'MA, Ehr.— A genus of Dia-
tom aceae.

Char. Frustules stipitate, navicular, some-
what arched (side view) ; valves with a
submedian line, with central and terminal
nodules (= stipitate Cymbettce). Fresh
water.

Valves transversely striated, the striae
being resolvable into dots.

7 European species (Rab.).

C. lanceolatum (PL 16. tigs. 19 & 20).
Front view of frustules lanceolate, truncate
at the ends ; valves semilanceolate, very
slightly inflated at the centre of the concave
margin; length 1-150". Common. Stipes
dichotornous, jointed.

C. cymbiforme. Scarcely distinct from
the last (Sm.) j stipules filiform, obsolete,
interwoven into a gelatinous mass ; length
1-330".

C. cistula. Front view elliptic-oblong,
obtuse ; valves inflated on concave margin ;
stipes elongate, filiform, simple or subrace-
mose ; length 1-450" ; common.

C. parvum (Sm.). Several other foreign
species.

BIBL. Ehr. Inf. ; Smith, Br. Diat. i. 75 ;
Kiitz. BacilL, and Sp. Ala. 59.

COCCOSPH^E'RA, Perty.— An obscure
genus of Infusoria (Algae ?), consisting of

a black,
into ir-
diam. j

they exhibit slow motion. In turf-pits
&c.

BIBL. Perty, Kleinst. Lebens. 1852, 104.

COCCOSPHERES.— The name given
by Wallich to minute lumps of colourless
protoplasm, found in deep-sea ooze, and
floating in the tropics. He describes them
as spherical or multilobed, from 1-5000 to
1-830" in size, imitating in shape Orbulina,
Nodosaria, Textilaria, Rotalia, and Globi-
gerina, and coated with numerous oval
Coccoliths (PI. 23. tig. 56 a).

From the Atlantic ooze, also, Huxley
describes minute granular colourless sarcodic
bodies as Coccospheres, 1-4500 to 1-1700"
in diameter, some having Coccoliths on or
in them ; and he distinguishes (1) the com-
pact, hollow, flattened sphaeroids with an
envelope, and (2) loose (1-4500 to 1-760").
The corpuscles are free, touching or over-
lapping, 1-11000 to 1-4500" in breadth,
sometimesmingled with Coccoliths (1-1 1000
to 1-1600").

BIBL. That of COCCOLITHS, and Wallich,
Ann. N. H. 1877, xix. 342 (tigs.).

COCCUDI'NA, Duj.— A genus of Infu-
soria, of the family Plcesconina.

Char. Body oval, depressed or almost
discoid, often slightly sinuous at the margin;
convex, furrowed or granular and glabimis
above ; concave beneath, and furnished with
vibratile cilia and cirri or corniculate ap-
pendages, serving as legs ; no mouth.

The species of this genus known to
Ehrenberg are arranged among his Oxy-
trichina and Euplota.

C. co&tata (PL 50. tig. 3). Body obliquely
narrowed and sinuous in front, convex and
furrowed above, or with from five to six
very projecting tubercular ribs ; appendages
grouped at the two ends ; the anterior more
slender and vibratile ; length 1-950" ; in
marsh-water.

Three other species. Dujardin remarks
that EhrenbergV genus Aspidisca belongs
here.

BIBL. Dujardin, Infus. 445; Claparede
and Lachmann, Infus. 188.

COCKCHAFER. See MELOLONTHA.

COCK-ROACH, or house black-beetle.
See BLATTA.

COCOA. — This substance consists of the
seeds of Theobroma Cacao (Ternstrcemia-
ceae), and is largely used in a manufactured
form under this name ; and, mixed with
sugar and other ingredients, it forms choco-
late. The various powders and pastes thus
designated are often very extensively

COCOA-NUT.

[ 189 ]

CODOSIGA.

falsified. A difference of quality is in the I
first place produced by the admixture or
exclusion of the husk of the seeds j still
more important degradation arises from
the use of flours of various kinds, ground
roots such as chicory added to give weight,
together with coloured earths to disguise
these.

The tissues forming the husk of the Cocoa-
seed include outer loose filamentous cells,
belonging rather to the seed-vessel j a mem-
brane composed of a single layer of flat
parenchymatous cells with thin walls (PI. 2.
fig. 4 a) ; and another, thicker, consisting of
a number of layers of large parenchymatous
cells containing mucilage and crystals (fig.
4 b), with spiral vessels and woody fibre ;
the outer part of the dark-coloured albu-
men of the seed is composed of angular, the
internal mass of rounded cells of delicate
structure filled with oil-globules and starch-
granules (PL 2. fig. 4 e). In the interspace
between the lobes occurs a finely fibrous
tissue, in which are found crystals. The
presence of the filamentous, the large paren-
chymatous cells, and the spiral vessels indi-
cates when the bark lias been ground up
with the finer part of the seed.

The various flours and starches are to be
detected by the characters of their granules
(STARCH) ; the pitted ducts betray the pre-
sence of chicory or other roots (see Cm-
con Y).

Chocolate is a compound made up with
starches and sugar, and flavoured with
cinnamon, vanilla, and other ingredients.
The examination of its preparations must
perhaps be limited to comparative richness
in cocoa, and to the detection of coarse sub-
stitutes for arrowroot and similar starches.
BIBL. Hassall, Food and its Adult. 207.
COCOA-NUT.— The seed of the Cocoa-
nut Pahn, Cocos nucifera (Monocotyledon).
Sections of the remarkably hard shell of
this nut afford good specimens of very
greatly consolidated woody tissue ; while
the fleshy contents form an example of
oily albumen, the soft thick-walled cells
containing abundance of drops of oil in their
cavities. The husk of the nut is composed
of fibres analogous in their structure to
liber, and used for similar purposes. See
FIBROUS STRUCTURES.

CODI'OLUM, Brauu.— A genus of Uni-
cellular Algae, of which the only known
species, C. gregarium (PI. 5. fig. 6), is
marine. It consists of a clavate tubular
cell, attenuated from about midway into

a slender base, by which it is attached to
piles, &c. Length, when full-grown, about
1-25", diameter of the clavate part about
1-300" ; green above, clear below. The
green contents are finally converted into
many 2-ciliated zoospores, which escape by
rupture of the cell, as in the sporanges of
Codium.

C. gregarium was found at Heligoland, on
submersed timber, and may be looked for
on the British coast.

BIBL. Braun, Alg. Unicell, 1855, 19, pi. i.

CO'DIUM, Stackh.— A genus of Sipho-
nacese (Confervoid Algee) ; marine. The
species have dark green spongy fronds of
cylindrical, flat, globular or crust-like form,
some inches in size, composed of interlacing
continuous filaments devoid of septa, ter-
minating in radiating club-shaped filaments
at the surface (fig. 133). The sporanges

Fig. 133.

Codium tomentosum.

Saccate cells arising from the filaments at the surface.
Magnified 10 diameters.

(spores) are produced in lateral branches
from the clavate cells, forming long elliptical
sacs, the contents of which are converted
into a vast number of biciliated zoospores,
discharged when mature (PI. 6. fig. 15).

BIBL. Harvey, Br. Mar. Alg. pi. 24 A ;
Phyc. Brit. pi. 93. 35 B ; and Thuret, Ann.
So. Nat. 3 ser. xiv. 232, pi. 23. figs. 1-5.

CODONEL'LA, Haeckel.— A genus of
Heterotrichous Infusoria (?) ; closely re-
sembling minute Medusa (Jen. Zeitschr.
1873; Kent, Inf. 615, figs.).

CODONCE'CA, Clark.— A genus of Fla-
gellate Infusoria.

Char. Solitary, 1 -flagellate, sessile, in an
erect stalked lorica.

2 species : marine and fresh water. (Kent,
Inf. 261.)

CODOSI'GA, Clark.— A genus of Fla-
gellate Infusoria.

Char. Ovate, attached to a simple or

CCELASTRIUM.

COLACIUM.

branched pedicle, with a collar, and a single
flagellum ; reproduction by longitudinal
division, and encysting, with division into
germs.

C. botrytts=Ejristylis b. Ehr. (PI. 53. fig.
15). Fresh water. 9 other species. (Kent,
In/us. 333.)

CCELASTRUM, Nag.— A genus of Pedi-
astreae (?) (Confervoid Algae).

Char. Cell-group or frond globose, hol-
low internally, formed of a single reticular
layer of green cells.

C. Naegelii (PI. 3. fig. 8). 3 other species :
found in boggy pools.

BIBL. Nageli, EinzeU. Alg. 97; Raben-
horst, Flor. Alg. iii. 79.

CCELENTERA'TA,Leuck.— Asubking-
dom of the ANIMAL KINGDOM, composed
of the Zoophytes.

C(ELOCYS'TIS,Kutz.— Probably a rest-
ing form of EUGLENA, Henf . ; = Ccelosphce-
rium, Rab.

CCELO'MON AS, Stein. —A genus of Fla-
gellate Infusoria.

Char. Free, 1 flagellum, variable, mouth
leading to a large chamber.

C. grandis = Monas g. Ehr. (PI. 53. fig.
16) : marsh-water. (Kent, Infus. 392.)

CCELOSPH^'RIUM, Nag.— A genus of
Palmellacese (Confervoid Algae).

Char. Frond globose, minute, hollow
within, consisting of minute seruginous
cells immersed in a simple mucous enve-
lope.

3 species. In ditches and pools.

BIBL. Rabenhorst, Fl.Alg.ii. 64; Archer,
Qu. Mic. Jn. 1879, xix. 440.

C(ENOCO'LEUS,Berk. and Thwaites.—
A genus of Oscillatoriaceae, distinguished
by the filaments growing "within a tough,
sidnny,more or less permanent outer coat."
C. Smithii forms a red mat of interlacing
threads on boggy soil ; the separatejfilaments
are green. C. cirrhosum, Eng. Bot. p. 2920,
is a DESMONEMA.

BIBL. English Sot. Suppl. pi. 2940.

C(ENOGO'NIUM,Ehr.— A doubtful ge-
nus of tropical Lichens, usually placed
among the Lecideinei. The thai his has a
cuticiuar stratum variously and curiously
marked.

14 species, growing on leaves, trees, and
earth.

BIBL. Leighton, Ceylon Lich. 172.

CCENU'RUS, Rudolph!.— A supposed
genus of Entozoa, placed in the order Ste-
relmintha, and family Cystica ; since proved
to be nurse-forms or larvae of Tccnice.

Char. A simple vesicle filled with an
albuminous liquid, upon the outer surface
of which a number of soft, short, retractile,
cylindrical and rugose rather than jointed
bodies (scolices) are situated. The head
of each resembles that of a Teenia, having
four disks and a crown of hooks.

C. cerebralis (PL 21. fig. 10) is the larva
of Tccnia coenurus, which infests the dog.

It occurs in the brain of sheep, producing
the t{ staggers ; " sometimes also in that of
the Horse, the Ox, the Rabbit, &c. The
vesicle is as large as the egg of a hen or a
pigeon. The scolices when extended are
about the 1-5 or 1-6" in length. When re-
tracted they appear to the naked eye as
opaque white specks.

Other kinds occur in the lemur and the
rabbit.

BIBL. Dujardin, Helminthes, 636; Kii-
chenmeister, Parasiten ; Cobbold, Entozoa,
1879.

COFFEE.— The "berries," as they are
vulgarly called, of coffee, are the seeds of
Coffesa arabica, a Dicotyledonous plant, of
the Nat. Order Cinchonaceaa.

The " berries " consist of a mass of hard
endosperm (horny ALBUMEN), composed of
closely adherent thick-walled angular cells
(PL 2. fig. 5 6), with a thick skin composed
of a layer of thin-walled parenchymatous
cells forming a membrane, and a layer of
hard, easily separable, pitted, thick- walled
parenchymatous cells of larger size (PL 2.
fig. 5 a) ; true spiral vessels occur in the
groove on the inner face of the seed. Ground
coffee is subject to very extensive adultera-
tions, recognizable under the microscope;
by which the vascular and parenchymatous
tissues of roots, the starch or the integu-
ments of various grains and seeds, &c. (men-
tioned more particularly under CHICORY)
may be discovered.

BIBL. Hassall, Food $c.

COIR. — The term coir-rope is applied to
cordage manufactured from the fibrous tis-
sue of the husk of the cocoa-nut. See
FIBROUS STRUCTURES.

COLA'CIUM, Ehr.— A genus of Flagel-
late Infusoria.

Char. Flagellum single, free like Euylena
or attached by a simple or branched stalk,
green, with red eye-spot.

C. vesiculosum (PL 30. fig. 32). Ovato-
fusiform, variable, internal vesicles distinct,
length 1-860". Fresh water, on Cyclops &c.

C. stentorium. Cylindrical, conical, or
funnel-shaped; variable, vesicles less dis-

COLEOCHJETE.

COLEOSPORIUM.

134.

Fig. 136.

Fig. 135.

tinct, pedicel generally branched, bright
green ; length 1-800". Other species ;
mostly on Entomostraca (Ehr. Inf. 115 ;
Kent, Inf. 393).

COLEOCHJE'TE, De Brebiss.— A genus
of ChastophoraceEe (Confervoid Algae), of
which one species, C. scutata, is apparently
pretty common in freshwater pools, forming
minute green disks (fig. 134) adhering to
leaves, to the larger Confervas, sticks, &c., I
also to the sides of glass vessels in which
aquatic plants are kept growing. The disks
are formed of a number of dichotomous
filaments radiating from a central cell and
cohering laterally, the whole being closely
applied on the surface of support, so that
the discoid form is occasionally modified by
this (we have seen it forming a kind of cup
and irregular fan-like lobes, on the ends of
the articulations of Hydrodictyori) . In cer-
tain cases the filaments are more or less free
from their lateral union. From the back of
many of the cells projects a long, tubular

Coleochsete scutata.

Fig. 134. A perfect plant. Magnified 25 diameters.

Fig. 135. Cells with tubular processes from the back
of the frond. Magnified 50 diameters.

Fig 136. Commencement of the development of a
young frond. Magnified ICO diameters.

process (fig. 134), with a bulbous base. Re-
production by zoospores ; and by fertilized
resting-spores (oospores). The former are
produced singly in the cells, from the whole
contents ; bear two cilia, and break out at
the back of the cell in C. scutata, from the
side in C. pulmnata. The resting-spores are
formed in cells near the margin, in penulti-
mate cells of the radiating filaments ; on the

back, therefore, in C. scutata, at the ends
of the branches in C. pulmnata. These en-
large very much, and become surrounded by
a kind of rind or cellular coat, through
growth of cellular branchlets from the pre-
ceding and the surrounding cells, which
branchlets meet and enclose them. The
sporanges, with their trichogynes open at
the end, receive the spermatozoids, and
their contents are then converted into 5-8
resting-spores. The resting-spores do not
directly form new plants, but numerous
swarm-spores, and exhibiting alternations
of generations : the first swarm-spores pro-
duce only asexual plants, with repeated
broods of swarm-cells; finally comes asexual
generation, monoecious or dioecious accord-
ing to the species ; and then the spores or
oogonia. The antheridia are flask-shaped
cells, situated near the sporanges ,• the sper-
matozoids are biciliated, one in each cell.

C. scutata, De Breb. (fig. 134) ; =P%/-
lactidium,Kutz. Fronds discoid, sporanges
on the back. On aquatic plants, &c., com-
mon. A variety, /3 soluta, occurs with the
radiating filaments more or less free.

C. pulmnata, Braun. Fronds composed
of tufted-branched, radiating, free filaments ;
sporanges globose, at the ends of the fila-
ments. Chatophora tuberculata, 0. Mull,,
according to Kiitzing.

Rabenhorst describes 7 species.

BIBL. De Brebisson, Ann. tic. Nat. 3 ser.
i. 29, pi. 2 ; Ralfs, Ann. N. H. xvi. 309,
pi. 10; Hass. Ala. 217, pi. 77; Braun,
Rejuv. (Ray Soc. 1853) ; Kiitzing, Sp. Ala.
424; Miiller, Regensb. 'Flora,' xxv. B. ii.
513, pi. 3; Pringsheim, Jahrb. 1860, ii. 1 ;
Rabenh. Flor. Alg. iii. 388; Sachs, Bot.
289.

COLEOP'TERA. — The 1st order of
Insects, containing the beetles. See Lsr-
SECTS.

COLEOSPO'RIUM, Leveille.— A genus
of Uredinei (Hypodernious Fungi), sepa-
rated from Uredo, which proves to be a
secondary form of many distinct and inde-
pendent plants (see UE'EDO). These fungi,
which may be well observed in C. sene-
cionis, Schlecht., and other common spe-
cies, appear as yellow, reddish, or brown-
ish pulverulent spots upon the leaves of
living plants. Their mycelium, creeping in
the intercellular tissues 'of the plants upon
which they are parasitic, consists of deli-
cate branched filaments, which collect toge-
ther at certain points, become interwoven,
at the same time acquiring orange or yellow

COLEOSPORIUM.

[ 102 ]

COLLFMA.

cell-contents, so as to form a flat cushion-
like body (clinode or stroma). From this
arise vertical or radiating, branched, club-
shaped, sac-like prolongations of some of
the filaments : the oldest are found in the
centre, the youngest at the circumference
of the group. The club-shaped bodies,
filled with yellow or brown contents, be-
come firmly coherent laterally (at this stage
they constitute Uredo tremeUosa). This
first spore is formed near the summit of the
clavate sac, leaving a little clear space at
the tip ; then a second spore below the first,
and so on to a third and a fourth, occa-
sionally to a fifth ; these increase in size so
as to conceal the existence of the sacs on
which they are seated ; only the tips of all
the laterally coherent sacs form oy their
union a transparent layer, presenting, when
seen from above, somewhat the appearance
of the comeae of the compound eye of an
insect. This lamella is burst open, with
the epidermis of the infected plant; and
the spores (now stylospores), which grow
into oval and globular forms, become de-
tached from one another and lie loose,
forming the yellow, red, or brown pulveru-
lent spots above alluded to. The spores
have a granular cuticle, and their coat is
double. The above is the Uredo-form ; be-
sides this, there is another form of fruit, in
which the stalked rows of stylospores are
represented by oblong 4-5-locular sacs, each
of the chambers of which ultimately emits
a long slender tube terminating in a minute
roniform ' pporidium ' (Tulasne). British
species (we cannot find distinctive cha-
racters) :

C. synantherarum, Fries. On Colt's-foot,
&c., common. U. compransor, Schlecht.
(in part) ; U. tussilayinis, Pers.

C. senecionis, Fr. On Groundsel, com-
mon. U. senecionis, Schlecht.

C. campanulacearum, Lev. On Campa-
nula. U. campanula, Pers.

C. rhinanthacearum. Lev. On Euphrasia,
&c. U. rhinanthacearum, De C.

C. pulsatillarum, Fr. U. pulsatillarum,
Strauss.

C. pinguis, Lev. On leaves, &c. of roses,
common. U. effusa, Strauss; Grev. Sc.
Crypt. Fl. t. 19.

BIBL. Leveille, Ann. Sc. Nat. 3 se*r. viii.
369; De Bary, Brandpilse, Berlin, 1853,
24, pi. 2 ; Fries, Summa Veyet. 512 ; Berk,
in Hook. Br. Fl. ii. pt. 2. 377-9, &c. ;
Tulasne, Ann. Sc. Nat. 4 ser. ii. 135, 179;
Cooke, Micr. Fungi.

COLEPI'NA, Ehr.— A family of Infu-
soria.

Char. Carapace barrel-shaped, traversed
longitudinally or transversely, or both, by
furrows, in which are situatecl minute vibra-
tile cilia; truncate, and either smooth or
dentate in front ; posteriorly pointed or ter-
minated by from two to five teeth ; fresh
and salt water.

Ehrenberg states that the oral and anal
orifices exist at the opposite ends of the
body. The gastric sacculi are readily filled
with colouring-matter. Motion, that of re-
volution upon the longitudinal axis.

A single genus : Coleps.

CO'LEPS, Ehr.— A genus of Infusoria,
of the family Colepina.

Char. Those of the family.

These animals are very' voracious, and
feed freely under the micioscope upon the
portions of the body of crushed Entomo-
straca, which attract'them as much as sugar
attracts flies.

C. hirtus (PI. 30. fig. 33 «, Ehr. ; fig. 336,
Duj.) Oval, white, rounded behind, cara-
pace tabulate, furrows transverse and longi-
tudinal ; posterior teeth three ; length 1-6/0
to 1-430".

/3 ehngatus. Cylindrical, elongate, length
as in the last.

C. viridis. Ovate, furrows transverse and
longitudinal, green, posterior teeth three;
length 1-960 to 1-570".

e C. amphacanthus. Ovate, carapace di-
vided by transverse furrows only, anterior
teeth unequal ; posterior teeth three, lare-e;
length 1-280".

C. incurvus. Oblong, nearly cylindrical,
slightly curved, white, posterior teeth five ;
length 1-430".

C. imcinatns, Berlin ; fresh water.

C.fmus, Norway.

BIBL. -Ehr. Inf. 317; Duj. Inf. 565;
Clapar. & Lachm. Inf. 366 ; Kent, Inf. 506.

COLLA'RIUM, Link.— A genus of Sepe-
doniei (Hyphomycetous Fungi). Filaments
crowded, septate, branched, with the spores
agglomerated in little spots upon them.

C. nic/rospermum, on dried paste ; C.
fmctigervm, on decaying apples. The
species should be referred to the Schizo-
mycetes.

COLLE'MA, Ach. — A genus of gelati-
nous Lichens. Thai! us without cortical
layer, but consisting of a gelatinous mass
of cells, with granular gonima in momli-
form series, and with Lecanorine reddish
apothecia j spores simple or septate. 40-50

COLLEMACEI.

[ 193 ]

COLLOSPILERA.

species ; of which 27 are found on earth,
rocks, trees, &c> in Great Britain.

BIBL. Nylander, St/n. 101, pis. 2, 3, 4;
Leighton, Lick. Fl 1879, 15.

COLLEMACEI.— A family of Lichens,
having a gelatinous thallus ; comprising
the tribes LICHENEI and COLLEMEI, which
see.

OOLLEMEL— A tribe of gelatinous
Lichens, farn. Collemacei, with a membra-
nous lobate thallus.

Gen. Pyrenopsis, Synalissa, Collema, Lep-
togium, Collemopsis, and Pyrenidium.

COLLEMOP'SIS, Nyl.-A genus of Col-
lemaceous Lichens, with the thallus glau-
cous-green internally. 7 British species.

BIBL. Leighton, Lich. FL 35.

COLLEN 'CH YMA.— A peculiar kind of
thickening of cellular tissue in the subepi-
dermal layers of many herbaceous stems,
such as Rumex, Beta, Chenopodium, &c. ;
which some have regarded as intercellular
substance, while bthers, more correctly, have
stated it to consist of metamorphosed se-
condary layers inside the cells. See INTER-
CELLULAR SUBSTANCE.

COLLETONE'MA,Brebisson.— A genus
of Diatoniaceae.

Char. Frustules navicular, sigmoid or
straight, arranged in rows, and immersed
in a gelatinous mucus, forming a filiform
frond. Fresh water.

C. eximium. Valves sigmoid; length
1-340".

C. rulgare. Valves elliptic-lanceolate,
slightly contracted at ends ; length 1-
410".

C. neglectum. Valves elliptic-lanceolate ;
length 1-250".

C. subcohcerens = Micromega subcohce-

Three other species, C. viridulum, C. la-
custre, and C. flexile.

Rabenhorst arranges these in a section of
the genus Schizotiema.

BIBL. Smith, Brit. Diat. ii. 69; Kiit-
zing, Sp. Alg. 105 ; Rabenhorst. Fl. Alg.
i. 265.

COLLOID MATTER, EXUDATION and
CORPUSCLES (animal).

The term colloid matter or exudation is
applied to a transparent, viscid, yellowish,
structureless or slightly granular matter,
resembling liquid gelatine, arising from the
metamorphosis of the protoplasm of the
cells. It occurs as a normal and a patho-
logical product. In a state of greater con-
sistence, it sometimes forms flakes or irre-

gular masses, which occasionally possess a
laminated structure. In a third form it
constitutes spherical, rounded or oval,
sometimes flattened microscopic corpuscles
— simple masses of sarcode (PL 38. fig. 22 a).
These are either homogeneous, or exhibit
numerous laminse (concentric colloid cor-
puscles) (PI. 38. fig. 226): sometimes a
kind of nuclear body is present (fig. 22 c);
at others they contain carbonate and phos-
phate of lime (fig. 22 d). Sometimes they
exhibit a radiate appearance (fig. 22 e). In
the liquid form, colloid exudation is found
within cysts in the thymus and thyroid
glands, the ovary, &c., and within the en-
larged areolae of areolar tissue around these
organs, &c. It is found in a free state upon
the surface of inflamed serous membranes.

The colloid corpuscles are met with in
the hypertrophied heart, in the prostate, the
thyroid, and the thymus glands, in the
choroid membrane, in the brain and spinal
cord, and in the (waxy) spleen, &c.

The liquid colloid matter is not precipi-
tated by acetic acid ; it becomes 91 a
gelatinous consistence, retaining its trans-
parency or turbid and opaque, by heat.
The colloid corpuscles do not, however,
appear to be uniform in composition : some-
times they consist of a proteine-compound ;
at others, doubtfully, of cellulose or amy-
loid, as in the brain (true CORPORA AMY-
LACE A). These bodies are further noticed
under the heads of the tissues and organs
in which they occur. See also TUMOURS
(Colloid cancer).

BIBL. Rokitansky, Path. Anat. i. 304;
Wedl, Path. Histol. ; Forster, Hand. spec.
Path. ; Virchow, Arch. Path. Anat. v. ;
Rindfleisch, Path. Gewebelehre, 29 j Green,
Pathol fyc. 57.

COLLO'MIA, Nutt.— A genus of Pole-
inoniaceae (Dicotyledons) remarkable for
the spiral structures produced in the epi-
dermis of the seeds (PI. 28. fig. 22) (see
SPIRAL STRUCTURES). The gummy sub-
stance in which fibre is imbedded is solu-
ble in water and not in spirit ; therefore
the best way to observe the elastic opening
of the spiral fibres is to make fine sections
of the coat of the seed and place them in a
little spirit of wine, upon a slide, with a
covering glass, to adjust the focus, and
then to add water carefully at the side of
the covering glass so as to wash away or
dilute the spirit.

COLLOSPILERA, Mull.— A genus of
Radiolaria, fam. Thalassicollidse.

o

COLORADO BEETLE. [ 194 ]

COLPODA.

Char. Skeleton consisting of simple sphe-
rical roundish or polyhedral fenestrated
shells, smooth or spinous, each of which
surrounds one of the combined central
capsules.

C. Huxleyi ( Thalassicolla pundata, pt.) .
Shell smooth; diam. 250"' In various seas.

C. spinosa. Shell spinous. Lessina.

BIBL. Haeckel, Radiolar. 633 ; Huxley,
Ann. N. H. 1851, viii. 434, pi. 16. fig. 6.

COLORADO BEETLE. See DORY-

PHORA.

COLOSTRUM.— The first liquid se-
creted by the mammary glands. See
MILK.

COLOUR. See INTRODUCTION, p. xxxiv.

COLOURING MATTER, OF ANIMALS.
See PIGMENT.

COLOURING MATTERS, of PLANTS.
— The green colour of vegetables depends
upon the presence of CHLOROPHYLL, and
is spoken of under that head. The red and
yellow colours assumed by leaves and her-
baceous shoots in autumn depend upon a
chemical metamorphosis of the chlorophyll,
or on its absorption and the discoloration of
the cellular tissue. The colours of red
cabbage, copper beech and similar plants,
depend upon the existence of a colouring
liquid in the usually colourless epidermal
cells, obscuring the chlorophyll which lies
beneath. The red colour presented by many
of the lower Algae, such as some of the
Palinellacese, appears also to depend upon a
metamorphosis of the chlorophyll, con-
nected with the vital processes ; it is met
with also in the contents of the resting-
spores of many of the filamentous Confer-
voids. The protoplasm assumes a reddish
colour in the pmictum vegetationis of the
buds of Monocotyledons in the autumn,
which probably depends upon a similar
cause. The bright colours of flowers and
other parts of the inflorescence of plants, as
also of the lower surface of many leaves
(Begonia, Victoria, &c.) and herbaceous
shoots, arise from the presence of matters
of a different kind, almost always dissolved
in the watery cell-sap. The colour of petals
is ordinarily found to depend upon a cer-
tain number of the cells subjacent to the epi-
dermal layer being filled with a coloured
fluid ; and the depth of the colour is pro-
portionate to the number of superimposed
layers of such cells, which act like so many
layers of a pigment. Each cell is usually
filled with one colour when fully deve-
loped ; but adjacent cells are often seen,

in Vciriegated petals, to contain distinct
colours, the line of demarcation being accu-
rately fixed by the cell-walls, through which
the colours do not transude, unless the cells
are injured by pressure. In young tissues
the colour often has a granular appearance
in the cells ; but this is a deception arising
from the mode in which the colour is deve-
loped. The colourless protoplasm originally
filling the cells becomes excavated, as it
were, by water-bubbles, and the watery
contents of the excavations become co-
loured ; they gradually enlarge as the pro-
toplasm applies itself more completely to
the walls of the cell, until they become
confluent and the coloured liquid fills the
whole cell-cavity. The isolation of the
coloured juice in each particular cell seems
to depend upon the primordial utricle or
parietal layer of protoplasm ; when this is
injured by pressure, or other external cause
endosmose is soon set up and the integrity
of the cell destroyed.

In some cases the liquid colouring-matters
of flowers have been found to contain solid
corpuscles : the red colour-cells of Salvia
splendens, and the blue ones of Strelifzia
regina, contain globules j and according to
Mohl, this is still more commonly the case
with the yellow colours : in the yellow
perigonial leaves of Strelitzia regina the
yellow colour is said to depend upon the
presence of crescentic and curled filaments
floating in the cell-sap.

The white patches upon variegated and
spotted leaves, such as those of Awnlcr,
Holly, variegated Mint, Begonia ari/yro-
stigma, &c., arise from the absence of chlo-
rophyll in the cells subjacent to the epi-
dermis at those parts, which producos the
same effects as we see in leaves mined by
caterpillars.

BIBL. Von Mohl, Verm. Schrift. 575.

COLPID'IUM, Stein, = Paramecfum M-
poda, Ehr. & Cl. & Lachmann (Kent, In/us.
537).

COLPOCEPH'ALCJM.— Asubgenus of
Liothenm (ANOPLURA).

C. longicaudwn, and four other species ;
found on pigeons.

BIBL. Megnin, Parasites, 91 (fig.).

COLPO'DA, Schrauk, Ehr.— A genus of
Holotrichous Infusoria, of the family Col-
podea, Ehr., Colpodina, Cl. & L.

Char. No eye-spot; body sinuous or
notched on one side, sometimes renifonn,
surface reticulated or marked with nodular
obliquely interlacing striae j mouth lateral,

COLPODELLA.

[ 195 ] CONCHOPHTHIRUS.

situated at the bottom of the notch, anc
furnished with a projecting lip.

C. cucullus (PL 31. fig. 25). Turgid
slightly compressed, reniform, often nar-
rowed in front ; length 1-1720 to 1-280"
Common is vegetable infusions, especially
of hay. Ecdysis has been observed • in this
animalcule.

Stein describes the encysting process and
reproduction from germs as occurring in
this infusorium.

C. ? ren. Ovato-cylindrical, reniform,
rounded at the ends; fresh wat. ; length
1-280".

C. ? cucullio (Loxodes cue. , Duj.). Com-
press<
front

id, flat, elliptical, slightly sinuous in
; fresh wat. ; length 1-900".

C. parvifrons, Cl. & L. No anterior re-
curvature, contractile vesicle not terminal.
Fresh water.

BIBL. Ehr. Inf. 347; Duj. Inf. 478;
Stein, Infusionsth ; Claparede & Lachniann,
270; Kent, Infus. 512.

COLPODEL'LA, Cienk.— A genus of
Flagellate Infusoria.

Char. Free or adherent, ovate or elon-
gate, one flagellum, with a suctorial cavity
at the base ; becomes encysted.

C. puynax (PI. 53. fig. 14). Fresh water ;
preying on Chlamydomonas ; length 1-2000' ' .
(Kent, Inf. 378.)

COLPODI'NA, Cl. & L.— A family of
Infusoria, characterized by the presence of
cilia all over the body, the patent and cili-
ated oesophagus, and the absence of rows
of buccal cilia directing the particles of
food to the mouth.

Genera :

Membranous lips absent.

No setae projecting from the

mouth 1. Paramecium.

Setae proj ecting from the mouth.
A bundle of short setae form-
ing a lower lip 2. Colpoda.

Oral setae long, isolated.

No ventral setae 3. Cydidium.

A bundle of ventral setae... 4. Pleuronema.
Lips membranous, oscillatory 5. Glaucoma.

COLPONE'MA, Stein.— A genus of
Flagellate Infusoria.

Char. Free, ovate, pointed and curved,
with a ventral groove ; flagella two, one
apical and vibratile, the other ventral and
trailing.

C. loxodes. Fresh water (Kent, Inf.
297).

COLUREL'LA, Bory. Duj. = Colurus,
Ehr.

COLU'RUS, Ehr.— A genus ofRotato-
ria, of the family Euchlanidota.

Char. Two frontal eye-spots; tail-like
foot forked; carapace cylindrical or com-
pressed.

Carapace open beneath ; cervical append-
age curved; jaws with two or three teeth
each.

C. deflexus (PI. 43. fig. 12, dorsal view;
13, ventral view ; 14, teeth). Carapace
ovate, compressed, its posterior points
long and directed downwards; terminal
points of foot (toes, E.) shorter than the
foot itself; length of carapace 1-240".
Freshwater.

C. caudatus. Carapace ovate, compressed,
posterior points of carapace distinct, points
of foot longer than the foot itself ; fresh-
water and marine ; length 1-240".

C. ? uncinatus and bictispidatus are doubt-
ful species,

BIBL. Ehr. Infus. 475.
COMBEA, D.N.— A genus of podetii-
form Lichens, tribe Roccellei. 1 species,
C. mollusca ; rocks, Cape of Good Hope.

BIBL. Ach. Meth. 235, pi. 4. f. 5 ; Nyl.
Syn. 257, pi. 8. f. 1.

COMPRESSOR. INTRODUCTION, p.
xxiii. ; Ross's new compressor is described
in Qit. Micr. Jn. 1864, 44,

COMP'SOGON, Mont.— A genus of Le-
nianeeoe (Confervoid Algae).

1 European species : C. Corinaldii. Ca-
pillary, much branched, violet. Freshwater.
CCJNCEPTACLE.— A form of fructifi-
cation in the FLORIDE.^ and FUCOIDEJE.
Also occurring in the fructification of some
Fungi.

CONCHCE'CIA, Dana.— A genus of Os-
tracode Entomostraca, fam. Conchceciadse.
Char. Those of the family.
C. oltusata, Sars. Shetland.
BIBL. Dana, Crustac. Explor. Expedit.
&c. ; Sars, Oversigt af Norges mar. Ostr.
118 ; Brady, Linn. Tr. xxvi. 469.

CONCHCE'CIADJE.— A family of En-
tomostraca, of the order Ostracoda.

Char. Inferior antennas 2-branched, one
branch rudimentary and immoveable ; feet
2 pairs, posterior rudimentary, eyes none.
1 genus, Conchcecia.

JONCHOPHTHI'RUS,Stein.— Agenus
of Holotrichous Infusoria.

Char. Free, oblong, dorsally convex,
striate.

C. anodont(e=Leucophrys an. Ehr. In
the " body-mucilage " of freshwater Mol-
lusca. 2 other species. (Kent, Inf. 490.)

o2

CONCRETIONS.

[ 196 ]

CONFERVA.

CONCRETIONS and CALCULI.—

These terms are rather indefinite. A hard
body of comparatively considerable size,
formed within an animal organism, would
be called a calculus, whilst a body of con-
siderable comparative size in which hard-
ness was not a marked feature, or a hard
body of small or microscopic dimensions,
would be called a concretion. Under the
latter term, the notion of a compound
structure is usually implied. Calculi gene-
rally consist of various organic and inor-
ganic substances entering into the compo-
sition of the secretions of the body, which
are precipitated from various causes. Those
found in the intestinal canal are mostly
composed of undigested vegetable tissues
derived from the food. Most, if not all,
calculi and concretions are mixed with ani-
mal matter (proteine-compounds) derived
from the mucous cavities in which they are
contained, — or simultaneously precipitated,
with their characteristic compounds, from
the secretions in the midst of which they
are formed. Hence when the proper cal-
culous matter is dissolved by a reagent
which exerts little or no action upon the
animal matter, a mass is left whicn exhi-
bits the form of the original body ; and the
organic cast often so resembles a cell, that
some hasty observers have attributed to
calculi a cell-origin.

Calculi and concretions enlarge by the
deposition of new matter upon their outer
surface ; and as this deposition is not uni-
form and uninterrupted, either in regard to
the nature or proportion of the respective
constituents, they mostly exhibit a lami-
nated structure. This is visible to the
naked eye in the larger ones, and evidenced
in those which are microscopic by the ap-
pearance of concentric rings, and of a
nucleus or nuclei. These concentric rings
and nuclei are distinguishable equally in
concretions formed artificially as in those
occurring naturally.

The inorganic matter in concretions is
in the crystalline state, the crystals being
usually small, granular or radiate, and in-
termingled with the organic substance ;
which arrangement is conveniently ex-
pressed by Ehrenberg's term "crystalloid."
The crystalloids have a great resemblance
to cells, for which they have often been
mistaken.

BIBL. Taylor, Hunt. Catalogue, Calculi ;
Quekett, Med. Times, 1851, xxiv. 551 ;
Grifiith, Med, Times and Gaz. 1852, xxv.

272; Rainey, Medico- Chir. Rev. 1857,
and Qu. Mic. Jn. 1858; Meckel, Mikro-
geologie.

CONDENSER, ACHROMATIC, BULL'S-
EYE, &c., for opaque objects. INTRO-
DUCTION, pp. xix & xx.

CONFER'VA, Plin.— A genus of Con-
fervacese (Confervoid Algse), which, as
restricted here, contains chiefly marine
species ; but we have thought it advisable
to retain in it the species separated by
Kutzing as Chcctomorpha and by Thuret as
Microspora ; so that our Conferva corre-
sponds to HassalTs proposed genus Apia-
nema. The plants consist of unbranched
filaments, composed of cylindrical or moiii-
liform cells, the length and diameter of
which have a very variable relation in dif-
ferent species, and containing starch-gran-
ules. The species with nioniliform cells
form Kiitzing's Glceotila. They are repro-
duced by zoospores formed from the cell-
contents. Braun says that C. bombycina
produces four in a cell. According to
Thuret, C. area produces large numbers,
which escane by a lateral orifice ; while the
species he describes as Microspora floccusa
forms a number which escape Dy a circular
dehiscence breaking up the filaments. The
zoospores are 2-ciliated in general, but
sometimes bear four. The spores have not
been observed; and hence Kiitzing has sug-
gested that the Conferva may be sterile
forms of (Edogonium ; but the true CEdogo-
nia produce solitary zoospores with a
crown of cilia. Ratenhorst describes 30
species. British species : —

Freshwater.

C. bombycina, Ag. Filaments 1-3GO to
1-180" in diameter, four or five times as
long, forming a yellow-green cloudy stra-
tum. Common in stagnant water. Dillw.
Conferva, pi. 60.

C.floccosa, Ag. (PI. 9. fig. lib). More
robust ; articulations once or twice as long
as broad. Microspora floccosa, Thuret,
Ann.des Sc.Nat. 3 ser. xiv. pi. 17. figs. 6,7.

Marine.

Thirteen species are described by Harvey
(Mar. Alga), of which C. area, Dillw., is
one of the commonest, remarkable for the
large size of the tufted filaments, as thick
as hog's bristles, growing 3 to 12" long, of
a yellow-green colour. C. Melagonium,
Web. and Mohr, has erect tufted filaments
equally thick ; while C. Linum, Roth, has

CONFERVACE^E,

[ 197 ]

CONFERVOIDE^E.

entangled filaments twice as thick, deep
glossy green, and many feet long.

The cell-walls of these large marine
species present a curious striated appear-
ance when treated with acids, which led
J. Agardh, apparently erroneously, to sup-
pose they are composed of spiral filaments.
(See SPIRAL STRUCTURES.)

BIBL. Harvey, Pliyc. Brit, j Thuret, loc.
cit. j Kiitzing, Sp. Alg. ; Hassall, Freshw.
Alg. 213 ; Braun, Rejuv. (Ray Soc. 1853,
184) ; Rabenhorst, Fl. Alg. iii. 322.

CONFERVA'CEJE.— A family of Con-
fer voidese. Marine or freshwater Algae ;
composed of articulated filaments, simple
or branched ; cells cylindrical, shortish, not
conjugating. The fourth and fifth genera
given below are placed here doubtfully;
Stigeodonium, if a good genus, leads to
Draparnaldia among the Chaetophoraceae.
Reproduction by zoospores; spores un-
known.

Synopsis of the British Genera.

Conferva, Filaments unbranched. Zoo-
spores minute, numerous in the cells. Sea,
brackish, and fresh water.

Glceotila, Microspora, Chcstomorpha, Cla-
dophora. Filaments tufted, much branched.
Sea and fresh water. Zoospores minute,
many in a cell.

Rhizoclonium. Filaments decumbent,
with small lateral rootlike branches. Zoo-
spores minute, numerous. Sea, brackish,
and fresh water.

Ulothrix. Filaments simple, often fasci-
culated, joints short. Zoospores 4-ciliated;
two, four, or more in a cell. Fresh water.

Stigeoclonium. Filaments branched, form-
ing tufts, the ramules running out into
slender points ; cell-walls often dissolving
to emit the zoospores. Zoospores 4-ciliated,
one in a cell.

CONFERVOI'DE^E or CHLOROSPO'-
RE^E.— An order of Algae. The Chloro-
spores or Confervoids, the lowest order of
the Algae, display a preponderating number
of truly microscopical plants, and constitute
one of the favourite and most instructive
fields of microscopic research. As yet, how-
ever, the minute history of development is
wanting in a very large number, while the
facts already disclosed are so varied that it
becomes a matter of difficulty to draw up a
sketch of their characteristics in a brief
space.

Among the Palmellaceae we find some of
the simplest forms of vegetable life, where

the organization is reduced to the condition
of a single microscopic membranous vesicle
enclosing nitrogenous contents, ordinarily
tinged with chlorophyll, and containing
starch. Such we have in Protococcus, which
in its various forms appears as a green or red
stain on damp surfaces, or a green or red
scum in water. These plants multiply by
the subdivision of the cells into two or four
new ones, which separate and repeat the
process. In addition to the vegetative

Ewth by subdivision, going on in damp air
s cells being held together more or less
ily in a gelatinous crust), the contents
of the individual cells are set free by solution
of the membranes when placed in water,
and emerge as ciliated zoospores, endowed
with active motion. Advancing a step, we
come to a number of genera not yet well
defined, in which the membranes of the
parent cells soften into a land of gelatine,
during the process of subdivision, and hold
the new cells together in groups of definite
or indefinite form; among these are Palmella
Gloeocapsa, and others of like nature, in
which at present no zoospores have been
discovered. In Coccochloris a process of
conjugation occurs. These genera exhibit
a ?'estingform, characterized by the increased
thickness of the membrane of the cell, and
a change of the green contents into a
brownish, reddish, or even crimson colour.
With the Palmellaceae we shall associate
a number of Unicellular Algae, whose cha-
racters and affinities are still obscure.

The Ulvaceae are not widely separated
from the Palmellaceae ; but the conjunction
of the cells into a definite membrane, indi-
cates a higher organization. In other re-
spects, however, they hardly differ more from
some of the more perfect genera of Palmel-
laceae, than those do from Protococcus ; and
therefore, although more conspicuous and
extensively developed than the Nostochaceae
and Desmidiaceae, it seems natural to place
the Ulvaceae near the Palmellaceae, espe-
cially as the reproduction by cell-division
and by zoospores is analogous in all respects
to what is seen in Protococcus, of which they
would appear to be the permanently aquatic
representatives. Prasiola and Schizogonium,
however, differ from the other Ulvaceae in
the absence of zoospores, the homogeneous
not granular contents of the cells being dis-
charged as motionless spore-like bodies,
from which new fronds grow up.

The Nostochaceae exhibit but a slight
advance in organization over the Palmel-

CONFEEVOIDE^E.

[ 198 ] CONFERVOIDE^E.

lacse. They are composed of linear series
of cells, mostly inflated so as to give the
filaments a beaded appearance ; the linear
series increase in length by transverse divi-
sion, and in some stages subdivide longitu-
dinally; larger globular cells (sporanges)
occur at intervals in the lines, with others
devoid of • endochrome (vesicular cells,
Thwaites). During the increase, the older
external membranes soften into a gelatinous
coat. In Nostoc, where the filaments accu-
mulate in large numbers, they lie elegantly
curled and entwined in masses of this jelly,
which exhibit a more or less definite, lobed,
external form ; appearing to the naked eye
as gelatinous crusts or globular masses,
as they lie upon damp ground or among
mosses. Each sporange produces one
resting-spore, which breaks out from it in
germination.

Nearly allied to Protococcus stands a
family which until recently have often been
regarded as animals, namely the Volvoci-
nese ; which consist essentially of groups of I
i organisms identical with the ciliated zoo-
spores, held together in a definite form by a
common membranous envelope or cceno-
bium, through which the cilia penetrate, so
that the entire full-grown plant moves free-
ly in the water, as in Volvox, Gonium, Pan-

j-spores,
fecundation by spermatozoids.

The Desmidiacese form another tribe of
very simple organization, where the indivi-
dual plant is composed of a single cell ; but
here the coat or enclosing membrane is pe-
culiarly characterized by the assumption of
remarkable forms unlike anv other vegetable
structures ; presentingangular and escalloped
outlines or elegant processes projecting from
the wall, but always so as to exhibit a bi-
lateral symmetry. These cells are isolated
or arranged in linear series or beautiful
complicated star-like groups, enclosed at
first in a common gelatinous envelope, but
readily breaking up into isolated frustules.
They are further remarkable for exhibiting
the process of conjugation with great dis-
tinctness; resulting in the production of
peculiarly formed bodies, zygospores, with
rigid external membranes, which are
generally regarded, probably correctly, as
sporanges. They are also reproduced by
zoospores.

The DiatomacesD are nearly related in
many respects to the Desmidiaceae ; but, on

the other hand, diverge from the ordinary
characters of plants so much in other re-
spects, that some authors have placed them
in the animal kingdom. Like the Desmi-
diacese, they are microscopic simple cells,
isolated or coherent in groups ; and either
free, or imbedded in a definitely or indefi-
nitely formed mucous nidus. They differ
however from the Desmidiacese, in possess-
ing, when free, a more active power of loco-
motion, and also by being often attached
by a kind of foot, and this either shigly or
in large polypiform families. Their great
distinctive character is the presence of a
siliceous coat to the cell, which preserves
the form of the organism when the soft parts
are removed by fire or acids. The cell-
contents of the Diatomaceae are usually of
a dirty yellow colour, the colour of the
chlorphyll being concealed by a yellow
matter— diatomine (phycoxanthine). The
reproduction is by division, and by conju-
gation, analogous to that of the " Desmi-
diacese.

The Oscillatoriaceae are truly filamentous
plants, the component parts of which, though
readily separating under external influences,
are often combined into complex fronds in
their normal state. The filaments of this
group are mostly very minute, and exhibit
transverse markings, which in some cases
are so delicate that they cannot be regarded
as actual divisions of cell-contents by septa j
yet the filaments break readily across in
these places, and the fragments go on grow-
ing. In the larger forms the articulations
of the cell-contents are more distinct ; but
even here the filaments look like rows of
individual masses of cell-contents contained
in a common tube, forming a kind of sheath.
In some genera the filaments are contained
in bundles in secondary sheaths. The most
remarkable point about this tribe is the
occurrence of the peculiar kind of motion
in the typical genus Oscillatoria, whence
it derives its name: the filaments emerge
readily from their sheaths and wave back-
wards and forwards, and the broken frag-
ments oscillate like the beam of a balance ;
from what cause, or by what means, is still
undecided.

The only known mode of reproduction is
by the breaking up of the filaments into
longer or shorter pieces, or into single joints.
Peculiar large cells occur at the base of the
filaments of some of the adnate genera ; but
their nature is unexplained.

The Siphonacese are plants of larger

CONFERVOIDEJE.

[ 199 ]

CONFERVOIDE^E.

dimensions and higher organization than
any of the preceding ; and indeed they are
placed among the lower Fucoids by some
authors. They seem to us to be more in
place here. They are composed of tubular
cells of much larger size than those of any
other Confer voids, the entire plant often
consisting of one undivided tube, while in
other cases the branches arise from true
articulations. In Botrydium a very curious
structure is exhibited : the plant consists
of a tough membranous globule, filled with
green matter, rising from a branched, colour-
less, root-like portion spreading in the damp
ground, the whole consisting only of one
very large undivided cell. In Vaucheria
and JSryopsis the tubular cell grows into a
long filament, more or less branched, but
not divided. In Hydrodictyon, which from
its general structure appears referable here,
the plant is a large net with meshes half"
an inch broad, the net itself being com-
posed of large tubes rounded at both ends,
articulated at the intersections of the meshes.
In Codium, the filaments are closely com-
bined into a spongy mass. The fructifica-
tion of these genera is very varied, so
that the group appears scarcely natural ; but
the plants are all more or less anomalous,
and have affinities with very different tribes,
while the comparatively enormous cells of
which they are composed are peculiar to
them among the filamentous Confervoids.
Vaucheria is reproduced by very large oval
gonidia covered with innumerable vibratile
cilia, by means of which they swim actively
in water ; the gonidia are developed from
the contents of the ends of the filaments;
and zoospores, produced under various cir-
cumstances, seem to occur in all the other
rnera. In Vaucheria sexual reproduction
also known ; sporangial and antheridial
branches being formed at the sides of the
main filaments. The Saprolegniece (Achlya,
&c.), were formerly included in this family,
on account of their general structure ; but
they are distinguished by the absence of
chlorophyll in their cell-contents, and their
parasitic habit, which gives them the cha-
racter of aquatic Fungi.

The (Edogoniaceae are green, simple or
branched, filamentous plants, attached to fo-
reign bodies under water — their cells, filled
with green matter, presenting a peculiar
mode of division ; and the entire contents of
the cells are converted into zoospores which
have a crown of numerous cilia. In the
sexual reproduction, the spores are formed

from the entire contents of certain cells,
which are impregnated by spermatozoida
produced on other parts of the plant, or by
antheridial plants developed from some of
the gonidia.

The Zygnemaceae are somewhat similar
filamentous plants, remarkable for the pro
cess of CONJUGATION or inosculation of
neighbouring cells of distinct filaments in
order to the production of the resting-
spores. They are also distinguished by the
endochrome being arranged in spiral bands
or other patterns on the cell-walls. It is
doubtful whether zoospores occur here
normally.

The Confervaceae are simple or branched
filamentous forma, of which the essential
characters are imperfectly known. They
produce numerous zoospores with two or
four cilia, in each cell.

The ChaBtophoraceae differ from the Con-
fervacese principally in their habit and mode
of branching. They occur in fresh water
and in the sea ; and are characterized by the
presence of a jelly enveloping the filaments,
which form branched, round, or shapeless
masses, or flat discoid or irregular plates,
and by the cells constituting the joints of
the filaments bearing slender bristle-like
branches. They are reproduced by zoo-
spores, either numerous or solitary in the
cells, bearing four cilia; also by spores
formed after fecundation.

The Batrachospermeae exhibit a greater
complexity of structure, consisting of jointed
moniliform filaments, composed of rows of
cells, branched and bearing whorls of ramuli j
the filaments of the whorls dense, dichoto-
mous, and beaded, some of them growing
down over the central filament, and forming
a sheath round it. The fructification con-
sists of spore-like bodies, or cystocarps with
trichogynes, borne on the filaments of the
whorls, and of bodies resembling the an-
theridia of the Florideae. The plants are
brownish green or purplish, and occur in
fresh water.

The Lemaneeaa are freshwater Algae, oc-
curring in rapid rivers, attached to stones,
by some supposed to bear a close relation to
the lower Fucoids. The fronds are branched
and of leathery texture, consisting of tubes
composed of cellular tissue, — the superficial
layers small, polygonal, and firmly con-
joined— the deeper layers, bounding the
cavity of the tubes, lax and spherical. The
fructification consists of beaded filaments
arising from the internal cells, and grow-

CONFERVOIDE^.

200 ]

CONFEEVOIDE^E.

ing out freely in the cavity of the tube,
finally breaking up into the component
bead-like cells (spores), which reproduce
the plant. The genus Lemanea deserves
further investigation.

Synopsis of the Families.

LEMANEE^E. Frond filamentous, inar-
ticulate, cartilaginous-leathery, hollow,
furnished at irregular distances with whorls
of warts, or necklace-shaped. Fructification :
tufted, simple or branched, necklace-shaped
filaments, attached to the inner surface of
the tubular frond, and finally breaking up
into elliptical spores. Freshwater.

BATRACHOSPERMEJE. Plants filamen-
tous, articulated, invested with gelatine.
Frond composed of aggregated, articulate,
longitudinal cells ; whorled at intervals with
short, horizontal, cylindrical or beaded,
jointed ramuli. Fructification: ovate scores,
and tufts of antheridial cells attached to
the lateral ramuli, which consist of minute,
radiating, dichotomous, beaded filaments.
Freshwater plants.

CH^TOPHORACEJE. Plants growing in
the sea or fresh water, coated by gelatinous
substance : either filiform, or (a number of
filaments being connected together) consti-
tuting gelatinous, definitely formed or shape-
less fronds or masses. Filaments jointed,
bearing bristle-like processes. Fructifica-
tion : zoospores produced from the cell-con-
tents of the filaments ; resting-spores formed
from the contents of particular cells after
impregnation by ciliated spermatozoids pro-
duced in distinct antheridial cells (Coleo-
'

CONFERVACEJE. Plants growing in fresh
water, or in the sea, filamentous, jointed,
without evident gelatine (forming merely a
delicate coat around the separate filaments).
Filaments very variable in appearance, sim-
ple or branched ; the cells constituting the
articulation of the filaments more or less
filled with green or very rarely brown or
purple granular matter, sometimes arranged
in peculiar patterns on the walls, and con-
vertible into spores or zoospores. Not con-
jugating.

ZYGNEMACE^:. Freshwater filamentous
plants, without evident gelatine, composed
of series of cylindrical cells, straight or cur-
ved. Cell-contents often arranged in elegant
patterns on the walls. Reproduction result-
ing from conjugation, followed by the de-
velopment of a true spore, in some genera

dividing into four sporules before germina-
tion.

(EDOGONIACEJE. Simple or branched,
freshwater, filamentous plants, attached
without gelatine. Cell-contents uniform,
dense. Cell-division accompanied by cir-
cumscissile dehiscence of the parent cell,
producing rings upon the filaments. Re-
production by zoospores formed of the whole
contents of a cell, with a crown of numerous
cilia ; and resting-spores formed in sporan-
gial cells after fecundation by ciliated sper-
matozoids formed in antheridial cells.

SIPHONACE/E. Plants found in the sea,
fresh water, or on damp ground ; of a mem-
branous or horny hyaline substance, filled
with green granular matter. Fronds con-
sisting of continuous tubular filaments,
either free or collected into spongy masses
of various shapes, either crustaceous, globu-
lar, cylindrical or flat. Fructification by
zoospores either single or very numerous ;
and by resting-spores formed in sporangia!
cells after the contents have been impregna-
ted by the contents of antheridial cells of
different form.

OSCILLATORIACE^J. Plants growing
either in the sea, in fresh water, or on damp
ground, of a gelatinous substance and fila-
mentous structure. Filaments very slender,
tubular, continuous, filled with coloured
granular, transversely striate substance ;
seldom branched, though often cohering
together so as to appear branched, usually
massed together in broad floating or sessile
strata, of very gelatinous nature ; occasion-
ally erect and tufted, and still more rarely
collected into radiating series bound together
by firm gelatine, and then forming globose,
lobed, or flat crustaceous fronds. Fructifi-
cation: the internal mass or the cell-con-
tents, separating into roundish or lenticular
gonidia.

NOSTOCHACE^:. Gelatinous plants
growing in fresh water or in damp situa-
tions among mosses, &c. ; of soft or almost
leathery substance, consisting of variously
curled or twisted necklace-shaped filaments,
colourless or green, composed of simple (or
in some stages double) rows of cells, con-
tained in a gelatinous matrix of definite
form, or heaped together without order in
a gelatinous mass. Some of the cells en-
larged, and then forming either vesicular
empty cells or densely filled sporangial cells.
Reproduction by the breaking up of the
filaments, and by resting-spores formed singly
in the sporanges.

CONFERVOIDE^E.

[ 201 ]

CONIFERS.

ULVACE^E. Marine or freshwater Algae,
consisting of membranous flat and expanded
tubular or saccate fronds composed of poly-
gonal cells firmly conjoined by their sides.
Reproduced by zoospores formed from the
cell-contents and breaking out from the
surface ; or by motionless spores f ormed from
the whole contents of a cell.

PALMELLACE^E. Plants forming gela-
tinous or pulverulent crusts on damp sur-
faces of stone, wood, &c., or more or less
regular masses of gelatinous substance, or
delicate pseudo-membranous expansions or
fronds, of flat, globular, or tubular form, in
fresh water or on damp ground j composed
of one or many, sometimes innumerable,
cells with green, red, or yellowish contents,
spherical or elliptical form, — the simplest
being isolated cells (found in groups of two,
four, eight, &c. in course of multiplication);
others permanently formed of some multiple
of four; the highest of compact, numerous,
more or less closely conjoined cells. Repro-
duction by cell-division ; by the conversion
of the cell -contents into zoospores ; and by
resting -spores, formed sometimes after con-
jugation, in other cases probably after
fecundation by spermatozoids.

We shall include under the head of Pal-
mellacese, all those obscure Unicellular
Algte whose place is not at present satis-
factorily known.

DESMIDIACEJE. Microscopic, gela-
tinous plants, of a green colour, growing in
fresh water ; composed of cells devoid of a
siliceous coat, of peculiar forms, such as
oval, crescentic, shortly cylindrical, or cylin-
dric-oblon^, &c., with variously-formed rays
or lobes, giving a more or less stellate form,
presenting a bilateral symmetry, the junc-
tion of the halves being marked by a division
of the green contents : the individual cells
either free, or arranged in linear series, col-
lected into faggot-like bundles, or in elegant
star-like groups, which are imbedded in a
common gelatinous coat. Reproduced by
division, and by resting -spores produced in
sporangia formed after the conjugation of
two cells and union of their contents ; and
by zoospores formed in the vegetative cells
(Pediastruni), or in the germinating resting-
spores.

DIATOMACE^). Microscopic cellular
bodies, growing in fresh, brackish, and sea-
water; free or attached; single or imbedded
in gelatinous tubes ; the individual cells
(frustules) with yellowish or brownish,
rarely greenish, contents, and provided with

a siliceous coat composed of two usually
symmetrical valves variously marked ; with
a connecting band or hoop at the suture.
Multiplied by longitudinal division ; and by
the formation of new larger individuals out
of the contents of conjugated cells ; perhaps
also by spores and zoospores.

VOLVOCINE2E. Microscopic, cellular,
freshwater plants, composed of groups of
bodies resembling zoospores, connected into
a definite form by their enveloping mem-
branes. The plants (families) are formed
either of assemblages of coated zoospores
united in a definite form by the cohesion of
their membranes, or of assemblages of naked
zoospores enclosed in a large common in-
vesting membrane. The individual zoo-
spore-like bodies with two cilia throughout
life, perforating the membranous coats, and
by their conjoined action causing a free
movement of the entire group. Reproduc-
tion by division {Gonium)^ or by single
cells becoming converted into zoospores
which conjugate and form new families
(Pandorina, Volvox) ; and by resting-spores
formed from some of the cells after im-
pregnation by spermatozoids formed from
the contents of other cells of the same
family.

BEBL. See the Families.

CONIDTA.— The name applied by Tries
to the stalked spores, stylogonidia, or repro-
ductive cells, produced directly from the
mycelium of many Fungi (PL 26. fig. 8) :
characteristic of the Coniomycetes. Late
discoveries have rendered the term of some-
what equivocal value; and it is not yet
sufficiently distinguished from STYLO-
SPORES and SPERMATIA. Physiologically,
thev are regarded as equivalent to the
gonidia of Lichens.

CONIF'ER^E.— A class of Gymnosper-
inous plants, so called from the peculiar
form of the female inflorescence, in which
the flowers are collected into imbricated
cones ; this is the case at least in the Abie-
tinese and Cupressineae : in the Taxinese,
which are separated by some authors, the
female flowers are solitary. These plants
are remarkable in many respects. The pro-
cesses occurring in the fertilization of the
ovules are quite different from those in the
Angiospermous flowering plants, and form
a link with the conditions in the higher
Flowerless plants. (See GYMNOSPERMIA.)
The pollen (PL 40. fig. 16) is of a remark-
able form in the Abietinese. The most
striking point, however, in relation to the

CONIFERS.

[ 202 ]

CONIOCYBE.

microscopic structure, is the condition of
the stems of these plants. The wood is
entirely composed of prosenchymatous cells,
of large size, without intermixture of ducts
or vessels; and those walls of the cells
parallel with the medullary rays (very
rarely those at right angles) are marked
with one or more rows of the peculiar bor-
dered pits which have been wrongly called
glands (PI. 1. fig. 4). The structure of
these is explained under the head of PITTED
STRUCTURES. It must be understood, how-
ever, that the peculiarity of Coniferous
wood does not depend on the presence of
these, which are common, but on the simul-
taneous absence of ducts. The wood of the
Yew presents in addition a spiral fibre, be-
tween the coils of which the pits lie. (See
TAXUS.J These peculiar conditions of the
wood render it possible to identify it in
microscopic sections in a recent, and, if
tolerably well preserved, even in a fossil
state; the Coniferous structure may be
readily detected in silicified wood, in which
almost all trace of organic matter is lost,
the silica forming complete casts of the
microscopic structures. This is beautifully
seen in some silicified wood brought from
Australia by Dr. Hooker, parts of which
are so friable, that microscopic sections
may be obtained by splitting it with a
knife (PI. 25. fig. 33). With solid silicified
wood, sections made by the lapidary are
required. We have also readily detected
the structure in COAL by the process we
have given under that head.

The only case of a structure approaching
near enough to that of Coniferous wood to
lead to misconception, appears to be that of
the wood of certain Magnoliacese, such as
Drimysj Sphcerostema, and Tasmannia, where
there is likewise absence of ducts and ves-
sels, while the prosenchymatous cells have
bordered pits ; out the wood differs consi-
derably in the character of the medullary
rays, and in the number and arrangement
of the pits on the walls of the cells. (See
WINTERED.)

The wood of many of the Conifers is
traversed by turpentine-canals, which are
large intercellular passages bounded by
thin-walled cells ; in others these occur
only in the bark, while in Taxus and Tor-
reya both are devoid of them : where none
occur in the wood, there are generally iso-
lated rows of cells filled with secretions ;
but not even these occur in the wood of
Abies pectinata.

The following analysis of the structure of
the wood of some of the most important, is
slightly modified from Hartig : —

A. Cells of the pith mth thin walls.
a. Liber-cells in cross-section broad \
and mostly short, isolated in scat- f A ____ „ _

tered groups, or in bandit ofseoe- f*Blf
ralrows, or wanting ............... /

*Wood with turpentine -canals.

t Medullary rays with varying pits Pinvs.
ttMedullary rays with uniform
pita.

^Cords of secretion-cells at the
outer limitof the annual rings.
$Outer wood-cells of the an- ) f, .

nual rings smooth within... |
§§Outer wood-cells of the an-"|
nual rings with an obscure \Larii.
spiral fibre ..................... J

1 1 Wood without isolated rows } «. n
of secretion-cells .................. I****

**Wood without turpentine-canals.

t Medullary rays with distant pits.

J Wood-cells with distant pits, 1

or 2 rows in pairs ...............

H Wood-cells with crowded pits,
1-5 rows, in spiral arrange-
ment.

} Ounninghamia.

b. Liber-calls with square or oblong^

cross-section, in concentric rows, ( TAXINE.E and

alternating with parenchymatous ( PoDOCARPKjE.

cells ....................................... )

*Pith with thick-coated liber-cells . Salisburia.
**Pith without thick-coated liber-
cells.
t Wood-cells with openly-coiled

spiral fibre ...........................

ft Wood-cells smooth within.

JLiber-layers with thick-coated

JJLiber-layers without thick- )
coated cells ........................ j

B. Cells of the pith with thick walls,

liber-cells square .................... .

*Liber-cells without pit-canals.
tPith with a roundish cross-sec- )

tion, bark without turpentine- > Taxodium.

canals ................................... j

ttPith with quadrangular cross- j

section, bark with turpentine- J- Thuja.

canals .................................... )

**Liber-cells with pit-canals.
t Wood-cells smooth inside.

TPith 3-angled ........................ Junipena.

JPith 2- or 4-angled ............... Cupressus.

t Wood-cells with a spiral fibre, ) rafrffi.

like Taxus .............. 7. .............. ^Calhtns.

BIBL. Goppert, De Conifer. Struc. 1841 ;
Anat. Magnoliac. Linnaea, xvi. 135, Ann.
Sc. Nat. 2 sǤr. xviii. ; Hartig, Botan. Zeit.
vi. 123, 1848 ; Schacht, Pflanzenzelle, 435 ;
Henfrey-Masters, Sot. 358, 625; Sachs
Sot. 496.

CONIO'CYBE, Ach.— A genus of Cali-
ciei (Lichenaceous Lichens), distin-
guished by the yellow powdery thallus,

CONIOMYCETES.

[ 203 ]

CONIOMYCETES.

globose yellow powdery stipitate head-like
apothecia, and colourless spores.

5 European, 3 British species.

BIBL. Leighton, Lich. JFl. G. B. 45.

CONIOMYCE'TES.— A section of Fungi
composed of microscopic forms, for the most
part parasitical upon plants, growing beneath
the epidermis, or overgrowing decaying ve-
getables, and then more or less imbedded in
the matrix. The fructification consists of
groups of sessile or stalked spores (sporidia,
Fries, and stylospores, Tulasne) arising from
the filamentous mycelium. In the simplest
forms the mycelium consists of short fila-
ments, which are more or less completely
converted into spores ; or it forms an irre-
gular flocculent patch in decaying matter or
under the epidermis of plants, in which the
spores are found intermingled, breaking out
on the surface of the epidermis in the para-
sites j but in the more complete forms the
mycelium becomes organized into firm struc-
tures of definite form (conceptacles) which
are hollow, the walls being lined with short
filaments terminating in spores. These
conceptacles are either produced on the sur-
face of the epidermis of the plant infested,
or they are formed internally, and are ex-
posed by breaking their way through to the
surface of the epidermal structures in which
they are imbedded.

We must not omit, in giving a description
of this order as it stands in systematic works,
to notice that recent observations go to
prove that it rests upon a very insecure
basis, and that certain supposed genera be-
longing to it appear to be merely forms of
genera which exhibit at other stages of
growth, or even at the same time, asciferous
structures which have formed the bases of
Ascomycetous genera. The following is a
summary of the views of Tulasne on these
points : — The Hypoxylous Fungi possess
at least four distinct kinds of organs of re-
production, among which the conidia hold
the first rank ; these are bodies of various
forms arising directly from the mycelium,
or from the stroma which is formed upon
this. Conidiiferous forms of Sphaeriacei,
which have been regarded as autonomous
Fungi, have given origin to the f oh1 owing-
genera of this order:— Melanconium, Stilbo-
spora, Steganosporium, Coryneum, Exospo-
riiim, Cylindrosporium, Macrosporium, Ver-
micularia, Mystrosporium, Cladosporium,
Helminthosporium, Periconium, Polythrin-
cium, Tubercularia, Stilbum, Atractium, Gra-
phium. The stylospores are the naked and

primitive stipitate spores formed in the con-
ceptacles, called by Tulasne pycnidia ; he
regards as pycnidial forms of Sphseriacei
most of the species of the genera Diplodia,
Sporocadus, Sphecropsis, Hendersonia, M^xo-
cycluSj Phyttosticta, Phoma, and their allies.
These forms almost always occur united
with the perfect or Ascomycetous forms to
which they are to be referred. A third
kind of acrogenous bodies occur often in the
same conceptacles as the stylospores, but
are much smaller, ordinarily of linear form,
and are usually confounded ultimately into
a gelatinous mass ; these are the spermatw,
which are supposed to exercise a fertilizing
influence. The genera Cytispora, Nema-
spora, LiberteUa, Septoria, Cheilaria, Lepto-
thyrium, &c., are chiefly based on the sper-
mogonous apparatus of Sphoeriacei. The
fourth form of spore is found enclosed in
asci ; the presence of these ascospores forms
the basis of the class Ascomycetes. Further
details are given under the heads of the
families, and genera there referred to.

The Uredinei exhibit similar polymorph-
ism ; ^ since the genera there included, such
as ALcidium, Puccinia, based upon the most
perfect form of fruit, mostly exhibit also
a stylosporous form (on which is founded
the false genus Uredo), together with sper-
mogonia containing spermatia.

Synopsis of the Families.

PHEAGMOTRICHACEJE. Conceptacles
horny, breaking through the epidermis of
leaves, &c., at first closed, afterwards burst-
ing _ longitudinally j spores septate, and in
chain-like series, intermixed with para-
physes on the internal walls of the con-
ceptacles,

TORULACEI. Mycelium filamentous,
growing on the surface of decayed vegeta-
bles, bearing erect filaments, terminating in
rows of simple or compound spores.

UBEDINEI. Mycelium a filamentous
mass growing in the interior of living vege-
table structures, finally breaking out on the
surface in patches, margined or naked, and
bearing simple or compound spores, single
or in beaded series.

USTILAGINEI. Mycelium filamentous,
growing in the interior of organs of plants,
producing simple or septate spores, finally
breaking up, without bursting through to
the surface, so as to leave a cavity full of
dust-like spores.

BIBL. Berkeley and Broome, Hooker's

CONIOPHYTUM.

[ 204 ]

CONJUGATION.

London Journ. of Bot. iii. 320 ; Tulasne,
Compt. Rendus, March 1851 (Ann. N. H.
1851, viii. 114) ; Ann. Sc. Nat. 3 se*r. xv.
370, xx. 129, 4 s<$r. ii. 77, v. p. 108; Botan.
Zeit. xi. 49; Compt. Rend. 1854 (Ann. N.
H. 2 ser. 1854, 76) ; Fries, Syst. Mycol ;
De Bary, Brand-Pilze, Berlin, 1853.

CONIO'PHYTUM, HassaU (Dolicho-
spermutn, Ralfs).— A genus of Nostocha-
ceae (Confervoid Algae), consisting of one
species ; colouring large sheets of water of
a deep coppery green, by its minute fronds,
each composed of a number of filaments
variously curled and interwoven, densely in
the centre, and more loosely towards the
circumference ; these fronds being free, look
like a pulverulent or granular accumulate >n
in the water, when viewed by the naked J
eye. The genus differs from its allies in
the relative positions of the spermatic and
vesicular cells, the former being either !
next to, or at a distance from the latter.
This fact seems to throw some doubt on
the value of this character as a distinctive
mark.

C. Thompsoni, Ralfs (PI. 3. fig. 9), = Do-
lichospermum Thomp., Ralfs, Ann. N. H.
1850, v. 336, pi. 9. fig. 3. Anabaina Flos-
aqua, Harvey, Brit. Alga, ed. 1 ; Hassall,
Alga, pi. 75. f. 2; also Bot. Gaz. 1850
(Colour of the Serpentine).

CONIOTHE'CIUM, Corda.— An obscure
genus of Torulacei (Coniomycetous Fungi) ;
the so-called species being probably forms
of some other Fungi.

C. amentacearum is extremely common
on dead willow-twigs.

BIBL. Berk, and Broome, Ann. N. H.
1850, v. 460 ; Corda, Ic. Fung. i. figs. 21,
25, 26 ; Fries, Summa Veget. 523.

CONIOTHY'RIUM, Corda.— A genus of
Sphaeronemei (Stylosporous Fungi).

C. glomeratum, Corda, recorded by Berke-
ley and Broome as Biitish, is said by Fries
to belong to his genus Clisosporum. It is a
microscopic plant growing in the cracks of
dead wood (elm) ; composed of minute free
membranous peridia enclosing numerous
spores, which escape by the bursting of the
apex.

BIBL. Berk, and Broome, Ann. N. H.
1854, xiii. 400; .Corda, iv. f. 208; Fries,
Summa Veget. 522 ; Montague, Ann. Sc.
Nat. 8 ser. xii. 304.

CONJUGATION or ZYGO'SIS. — A
process occurring among many of the lower
plants and animals, in which the substance
of two distinct organisms comes into con-

Fig. 137.

tact and becomes fused into a single mass, or
zygospore. This operation is always con-
nected with reproduction in plants, some-
times also in animals.

In the vegetable kingdom it has been ob-
served in the Algae, viz. in the Zygnemaceae,
the Desmidiaceae, the Diatomaceae, the Pal-
mellaceae, and in the genus Syzygites of
Fungi ; also in the Myxomycetes. It also
occurs in the zoospores. In all these cases
it consists essentially in the blending to-
gether of the contents of two distinct cells :
either by the complete fusion of two free
cells; by the passage of the contents of
one cell into the cavity of another through
newly-formed connecting tubes ; or by the
emission of the contents of both cells into
a space between them, where the mixed
contents become enclosed in a special en-
velope.

The conjugation ear-
liest discovered was that
of the Zygnemaceae, in
which the cells of dis-
tinct filaments lying pa-
rallel with one another,
become united by late-
ral inosculation or by
cross branches, formed
by the budding out of
the walls of the cells
opposite to each other,
the protruded processes
coming into contact, co-
hering and becoming
confluent by the absorp-
tion of the surfaces of
contact (fig. 137). The
cavities of the two cells being thus freely
opened into one another, the contents be-
come mixed ; in Spiro-
gyra and Zygnema the
contents of one of the
cells usually travel
across into the cavity of
the other (PI. 9. fig. 18);
in Zygogonium the con-
tents of both cells collect
in the cross-piece, this
is the case also in Meso-
carpm (fig. 138) and
Staurocarpus, in the lat-
ter of which the cross-
piece becomes greatly
enlarged. The contents

in all these Cases be- Conjugating filaments

come retracted from the
cell-wall, and, secreting

Zygnema cruciata.
Conjugating filaments.
Magnified 250 dia-
meters.

Fig. 138.

Mesocarpus acalaris.

with spores.
Magnified 200 dia-

CONJUGATION.

[ 205 ]

CONJUGATION.

Mougeotia genuflexa.
Conjugating filaments.
Magnified 100 diameters.

special coats, become spores, which escape by
the rupture of the conjugated cells. In Mou-
geotia (fig. 139)
there is no cross- Yi°-. 139.

branch. The fila-
ments become an-
gularly bent and
inosculate at the
angles. A spore
is said to be form-
ed in each cell
here. (See ZYG-

NEMACE^E.)

Pseudo - spores
are sometimes
formed in the cells
of Zygnemacese
without conjuga-
tion, in which case
they are barren.

In the Desmidiaceae, the process pre-
sents a number of modifications. In the
filamentous forms, such as Hyalotheca and
Didymoprimn, conjugation does not usually
take place until the single cells of the
filaments have become separated ; but in
some cases, as in D. Borreri, conjuga-
tion of the filamentous groups has been
observed, perhaps this occurs in Des-
midium also. In Closterium, Penium, Tet-
memorus, Cosmarium, &c., the free cells
conjugate in pairs. In almost all these
cases the mode of union appears to be
different from that which is seen in Zygne-
macese ; for the external membrane dehisces
more or less completely, so as to separate the
parent-cells into two valves, while a deli-
cate internal membrane previously lining
this is protruded as a sac, to meet its fellow
from the corresponding conjugating indivi-
dual; these sac-like processes coalesce, and
thus the contents of the cell are enabled to
mix. In Hyalotheca dissiliens and Penium
Brebissonii, there is said to be union of the
primary or outer cell-coat, as in Zygnema.
The resulting spore or sporangium is mostly
formed in the connecting piece (Closterium,
Cosmarium, Tetmemorus, Hyalotheca} (P1.10.
figs. 1-3) ; or in one of the cells (Didymo-
prium Grevillii, and perhaps in Desmidium).
In Closterium Uneatum it has been observed
that the conjugating cells divide completely
by constriction of their delicate internal
membrane just before conjugation, so that
the dehiscent primary membranes emit from
each parent individual a pair of little sacs,
in close apposition ; and these meeting their
fellows, a double or twin conjugation takes

place, and a pair of srjores or sporangia are
formed. A gelatinous investment is secreted
around the conjugating sac-like processes,
and the spore is generally at first imbedded
in an abundant gelatinous coat. (See DES-

In the Diatomacese there does not appear
to be any delicate internal membrane, like
that of the Desmidiacese, concerned in the
conjugation. The two conjugating indi-
viduals, lying near together, become con-
nected together by the excretion of a collec-
tion of gelatinous substance ; the siliceous
coats then dehisce, and the contents of the
parent-cells, escaping from the valves, meet
between them to unite into a globular mass,
which does not become a spore, but gradually
acquires the form of the parent. There is
no connecting tube here ; only the investing
gelatinous matter. In Himantidium and
Surirella, one new individual is formed in
the conjugation (PI. 10. fig. 5) ; in Eunotittj
Cocconema, Gotnphonema, and Schizonema,
the contents of the parent-cells appear to
divide transversely before extrusion, and
thus form a pair of new individuals in the
conjugation (PL 10. fig. 6) (as in the case
of the spores of the Closterium Uneatum).
A peculiar condition occurs in other genera
(Cydotella, Melosira, &c.)} which is supposed
to be a conjugation of the divided contents
of one frustule. (See DIATOMACE^J.)

Among the Palmellacese, conjugation has
been observed in Coccochloris Brebissonii
(Palmoglcea macrococca, Braun), where two
vegetative cells become completely fused,
membrane and contents, to form a spore
which acquires a firm coat and oily contents,
and passes through a stage of rest before re-
commencing vegetative development (PL 7.
fig. 6, c, d).

Fig. 139*.

Pandorina morum. Conjugation of zoospores.
Magnified 300 diameters.

The zoospores of Pandorina conjugate
much as in Coccochloris ; they approximate
by their apices (fig. 139*, 6), become fused (c)

CONJUGATION.

[ 206 ] CONNECTIVE TISSUE.

then lose their cilia, and acquire a red
colour, finally forming a resting spore (d).

The supposed conjugation of VAUCHERIA
and similar phenomena in some other Con-
fervoids, are cases of fecundation of sporangial
cells by unlike antheridial cells, no permanent
union taking place.

The well-known case of conjugation in
the Fungi described by Ehrenberg in
SYZYGITES, a genus of Mildew Fungi, is
described under that head. See also MYXO-

MYCETES.

De Bary, Tulasne, and others have ob-
served in several Fungi, as Eiysiphe, Pyro-
nema, Peranospora, &c., a sexual process
which is exactly analogous to what takes
place in certain Algae, and in the abnormal
Saprolegnice ; the body containing the male
element coming into contact with the female
organ, and thus producing fruit. This pro-
cess seems rather to come under the term
copulation than conjugation.

The conjugation observed in the animal
kingdom, consists in the direct union, by a
more or less extensive, sometimes complete,
fusion of the substances of two or more dis-
tinct individuals. In Diplozoon paradoxum
the two individuals become united by a
cross branch ; and the remarkable result is
that sexual organs become developed in
both bodies after this. Apparent conjuga-
tion takes place also in Actinophrys, Aci-
neta, Gregarina, &c. It is, however, pro-
bable that the fusion which occurs in many
of these cases is spurious, and unconnected
with reproduction.

Podophrya pyrum is one of the best in-
stances of true conjugation, the resulting
compound individual containing 8 embryos
in a single cavity common to both. The
true process has also been observed in Aci-
neta (mystacina), Vorticella (microstomd) ,
Paramecium, several Flagellata, &c. The
researches of Balbiani tending to show that
in many of the Infusoria the conjugation is
a true sexual process, have not been con-
firmed.

BIBL. Vegetables: Vaucher, Conferves-,
Meyen, Pflan.pliys. iii. 413 ; Hassall, Alyce ;
Kiitzing, Phyc. gen. ; Ralfs, Desmid. ; Mor-
ren, Ann. Sc. Nat. 2 se"r. v. 257 ; Smith,
Srit. Diat. ; Thwaites, Ann. N. H. xx. and
ser. 2. i. and iii. ; Braun, Rejuv. (Ray So-
ciety, 1853) ; Focke, Physiol. Studien, ii. j
Nh'geli, Algen-Syst. 175 j 'Karsten, Sot. Zeit.
x. 89; Ehrenberg Verhandl. Naturf. Freund.
i. 98 ; Areschoug, Swed. Trans. 1853 ;
Sot. Zeit. xiii. 364 ; De Bary, Conjugate,

1859 ; Griffith, Ann. N. H. 2 ser. xvi. 92 ;
Carter, ibid. xvii. 1 ; Hoffmann, Phys. Sot.
ii. 155 &c. ; De Bary, Ann. Sc. N. 1866,
343 ; Tulasne, I. c. 1806, 211 ; Rostafinakft
Sot. Zeit. 1871, 787. Animals: Kolliker,
Sieb. u. KoUik. Zeitsch. i. 1, 198 (Qu. Mic.
Jn. i. 98); Siebold, ibid. i. 270, iii. 62;
Stein, In/us. ; Wieymanris Archiv, 1849,
147; Nordmann, Mikr. Beitriige, i. 56;
Clapar. & Lachm. In/us, ii. 222 ; Allman,
M. M. Jn. 1875, xiv/178 ; Kent, Inf. 92.

CONJUNCTI'VA. See EYE.

CONNECTIVE TISSUE, OF ANIMALS,
sometimes called areolar or fibro-cellular
tissue.

Connective tissue is very generally dif-
fused throughout the bodies of vertebrate
animals, filling up the interspaces between
the various organs and structures, and
entering into the composition of most of
them.

There are several varieties.

The fibrous or areolar variety consists
essentially of white fibrous tissue, mostly
containing the elements of the yellow or
elastic tissue. The most common form of
the white fibrous element is that of minute,
delicate, transparent fibres, called fibrillte,
with pale outlines (PI. 49. fig. 41) ; these
are sometimes single, at others united into
bundles or fasciculi. The fibres as well as
the bundles sometimes pursue a straight
course ; at others they are elegantly curved
and wavy, interlacing* in all directions, and
leaving larger or smaller areolas or spaces
between them, the larger of which are
visible to the naked eye. The fibrillee are
about 1-40,000 to 1-20,000", and the fasci-
culi about 1-7000 to 1-3000" in diameter.
In the fasciculi, the fibres are connected by
an amorphous, transparent, gelatinous sub-
stance. Intermingled with the fibres, are
rounded, elongate, or branched cells (con-
nective corpuscles) or nucleated protoplasts,
which may be well examined in the trans-
parent laminae separating the muscles of a
frog's leg. Some of these are stationary,
but exhibit changes of form. Others are
locomotive, with amoeboid movement, and
correspond to the white blood-corpuscles.
The connective corpuscles may often be
rendered more distinct by staining with
magenta. When treated with acetic acid,
the fibres swell, become paler, and lose their
distinctness, the bundles appearing as if
fused into a gelatinous mass (fig. 29. p. 69) ;
and round or elliptical nuclei, with their
long axes parallel to the direction of the

CONNECTIVE TISSUE. [ 207 ]

COPPER.

fibres, are brought to view, as in PI. 49.
fig. 42.

The retiform variety consists of a very
delicate network of fine fibrils, formed ori-
ginally by the union of branched connective-
tissue corpuscles. This constitutes the
stroma of the spleen, and the lymphatic
glands. A still finer variety form the Neu-
roglia.

The yellow fibrous tissue occurs in the
form of fine or coarser fibres, with dark
outlines ; these sometimes run straight, or
are wavy or reticular ; at others they are
coiled or form rings around the bundles of
the areolar tissue, or running parallel with
and between them, sometimes forming per-
forated membranes. They are best seen
when the tissue has been rendered trans-
parent by the addition of acetic acid.

In the gelatinous or mucous variety, the
intercellular substance forms a soft semi-
transparent mass, containing rounded spin-
dle-shaped or branched cells, often united
by the branches ; it is met with in the In-
vertebrata, as the Meduscc, the integument
of the Mollusca, &c.

The truly cellular form, which is also
common among the Invertebrata, consists
of round or elongate cells, with but little
intercellular substance ; it occurs in the
Articulata, the Mollusca, and in the Chorda
dorsalis.

Connective tissue consists chemically of
gelatine, which may be obtained from it in
solution by boiling ; elastic tissue consists
of elastine.

The various complex structures into the
composition of which the connective tissue
enters, as the mucous membranes, skin, fatty
tissue, &c., are noticed under their respec-
tive heads. Cartilage and Bone are also
considered connective-tissue formations.

Connective tissue is' developed from the
embryonic corpuscles. These become elon-
gated, or fusiform, and branched. They
unite with each other, and the ends become
split into the component fibrillaa of the
future tissue. But whether the corpuscles
are solid bodies or protoplasts, or true cells,
is not at present agreed upon.

BIBL. Kolliker, Gewebelehre ; Mulder-
Bonders, Phys. Chem. ; Todd-Bowman,
Phys. An. ; Druinmond, Ed. Mn. Jn. 1852 ;
Rollett, Strieker's Handb. 38 ; Beale, Simple
Tissues ; Klein, Hist. ; Gegenbaur, Vergl.
An.\ Frey, Hist, and the copious Bibl. ;
Kirkes-Baker, Phys.] Rutherford, Histo-
logy ; Waldeyer, Arch. f. mik. An. 1876,

ii. 176 (M. M. Jn. xvi. 94) ; Satterthwaite,
Mn. M.Jn. 1876, xvi. 191,241 ; Flemming,
Arch. An. $ Phys. 1876, xii. 391.

CONOCEPH'ALUS, Hill. See FEGA-

TELLA.

OONOCHI'LUS, Ehr.-A genus of Ro-
tatoria, of the family QEcistina.

Char. Animals aggregated around a cen-
tral gelatinous nucleus, and forming a re-
volving sphere j two persistent frontal eye-
spots.

From ten to forty in each sphere. Nu-
cleus sometimes green, from the presence
of parasitic monads. Four thick conical
papillas arise from the middle of the frontal
surface, each having a bristle at its apex.

C. volvox (PI. 43. figs. 15-17). Cara-
pace and body white, gelatinous, and hya-
line; length 1-60", breadth of sphere 1-8".
Freshwater. 2 kinds of eggs — male and
female.

BIBL. Ehr. In/us. 393; Bavis, M. M.
Jn. 1876, 1 j Bedwell, Jn. Mic. Soc. 1878,
i. 176.

CO'NOBONTS.— Minute, slender, coni-
cal, curved, brownish bodies, found in a
sandy Lower Silurian clay near Petersburg,
and supposed by Pander to be minute fish-
teeth. Possibly they belonged to Cyclo-
stome fishes of extinct genera. They occur
also in later strata.

BIBL. Pander, Mon. foss. Fische, &c.,
1856; Murchison, Sihiria, 1859, 375, and
1867, 356 ; Hinde, Qu. Geol. Jn. xxxv. 356.

CONOS'TOMUM, Sw.— A genus of Bar-
tramiaceous Mosses. Conostomum boreale,
Sw., on Scottish mountains.

CONULI'NA, B'Orb.— A top-shaped,
many-chambered, stichostegian Foraminifer,
having the septal face slightly convex and
multiperforate, is the only recorded sample
of this doubtful genus, which is probably
related to Lituola.

BIBL. B'Orb. Foram. Cuba, 1839.

CONULI'TES, Carter.— A Foraminifer
of the Gloligerinida family, closely allied
to, if not the same as, Patettina.

BIBL. Carter, Ann. N. H. ser. 3, viii. 457 ;
Carpenter, Introd. For. 233.

COPE'POBA. See ENTOMOSTBACA.

COPPER.— Crystals of metallic copper
exist in artificial A VANTURINE. The acetate
of copper is noticed under ACETIC ACID.

Copper occurs in minute quantities, in
the human bile, biliary calculi, and the
blood ; and in the blood*of some Crustacea ;
also in the Cephalopoda.

The ammomuret of copper is prepared by

COPPINIA.

[ 208 ]

CORALLIUM.

digesting copper turnings in an open bottle,
with Liq. Amm. (P. B.) ; it must be used
fresh. Its action is well displayed when it
is brought into contact with cotton-wool.

COPPl'NIA, Hass.— A genus of Coppi-
niidae (Hydroid Zoophytes).

Char. Cells long, crowded, united by a
cellular mass at their bases ; ova developed
in the cavities of the cellular mass.

C. arcta. Incrusting the stems of other
zoophytes, common ; greenish yellow.

EIBL. Hassall, Mw?. TV.iii. 160; Hincks,
Brit. Zooph. 219.

CO'RA,Fr. — A tropical genus of Lichens,
approaching Coccocarpia.

1 species : C. pavonia.

BIBL. Fries, Syst. Orb. Veg. 300; Nyl.
Ann. Sc. Nat. 1865, iii. 151.

CORAL. — A term applied in general to
the calcareous polypiaom or skeleton of
Polypes or Zoophytes, and in particular to
that of CORALLIUM.

CORAL'LINA, Linn.— A genus of Co-
rallinacese (Florideous Algae), of stony cha-
racter, looking like corals. The common
C. offidnalis grows everywhere between
tide-marks, on rocks, &c. ; and presents a

Fig. 140.

Fig. 141.

Corallina officinalis.

Fig. 140. A branch of the frond. Natural size.

Fig. 141. A section of the end of a branch terminating
in a ceramidium, containing tetraspores. Magnified 10
diameters.

branched, mostly pinnate tuft of articulated
filaments evenly coated with carbonate of
lime. The tetraspores are borne in tufts in
ceramidia (tig. 141), usually at the apices
of the branches (being the last joints trans-
formed) ; or they occur laterally (fig. 140),
sometimes in pairs and sometimes irregu-
larly over the whole frond ; opening by a
small terminal pore (fig. 141).

The structure may be examined in these
plants, by keeping them for some time in
vinegar or dilute muriatic acid ; which will
remove the lime, and allow of the substance
being sliced in the same way as other Algae.
BIBL. Harvey, Mar. Alg. pi. 13 C ; Phyc.
Brit. pi. 222 ; Decaisne, Ann. Sc. Nat.
2 se*r. xvii. pi. 17. fig. 1, xviii. p. 119;
Solms-Laubach, Corall.-Algen Golf Neapcl,
1881.

m CORALLINA'CE^E.— A family of Flo-
rideae. Rigid, articulated, or crustaceous,
mostly calcareous sea- weeds, purple when
fresh, fading, on exposure, to milk-white ;
composed of closely-packed elongated cells
or filaments, in whicn carbonate of lime is
deposited in an organized form. Tetraspores
tufted, contained in ovate or spherical con-
ceptacles (ceramidia, Harvey), furnished with
a terminal pore. British genera :

* Frond filiform, articulated (Corallineae).

Corallina. Frond pinnated. Ceranridia
terminal, simple.

Jania. Frond dichotomous. Ceramidia
tipped with two horn-like ramuli.

* Frond crustaceous or foliaceous, opaque,
not articulated (Nulliporae).

Melobesia. Frond stony, forming either
a crustaceous expansion, or a foliaceous or
a shrub-like body.

Hildebrandtia. Frond cartilaginous, not
stony, forming a crustaceous expansion.

*** Frond plane, hyaline, composed of cells
radiating from a centre. Fructification
unknown (Lithocystese).

Lithocystis (a minute parasite).

CORALLINES.— The Corallinacese, a
family of Algae, were formerly imagined to
be of animal nature, and were classed among
the Zoophytes. On the other hand, Ellis
applied the term Coralline more extensively,
including under it Polyzoa (Bryozoa), and
Sertularian and similar Zoophjtes (Polypes);
the name is still often vulgarly used in this
sense. The term should properly be re-
stricted to the family to which the genus
Corallina gives the name.

CORAL'LIUM, Lam.— A genus of
Zoophytes, of the order Actinozoa.

The red coral of commerce is the inter-
nal skeleton of Corallium rubrum, Lam.
(Isis nobilis, Lin.) (PL 41. fig. 6 c). A por-
tion of the dried animal matter is usually

CORDYCEPS.

[ 209 ]

CORINNA.

found adhering to its surface, and contains
abundance of spicula (PI. 41. fig. 7).

The furrows seen upon the outer surface
of unprepared coral, are the impressions of
vessels which traverse the cortical substance
and form a medium of communication be-
tween the various polypes.

The structure of coral is rather obscure.
The transverse section (PI. 41. fig. 8 a) ex-
hibits somewhat undefined lines, some of
which are semiconcentric with the marginal
furrows, and appear to be lines of growth ;
these are intersected by darker and narrower
lines, apparently canals. The orifices of
larger canals are also visible. The longitu-
dinal section (PL 41. fig. 8 b) exhibits lon-
gitudinal lines, probably those of growth,
with an indistinct intermediate structure.
When treated with acid, the residue is soft
and easily folded so as to produce a lined
appearance ; and in parts the organic skele-
tons of spicula may be distinguished. Hence
it probably consists of spicula, aggregated
and ultimately consolidated, so that their
structure is no longer distinguishable.

BIBL. Cuvier, Regne Animal, 1853, Zoo-
phytes ; Lacaze-Duthiers, Hist. Nat. Corail,
1864; Dana, Corals, 1872; Nicholson &
Etheridge, An. N. H. 1877, xx. 161, 388 >;
Milne-Edwards & Haime, Monog. fossil
(Pal. Soc.) ; Duncan, ibid.

COR'DYOEPS, Fries. See SPHJERIA
and CLAVICEPS.

CORDYLO'PHORA, Allman.— A genus
of Zoophytes, order Hydroida, and family
Clavidae. * Freshwater.

Char. Polypidom horny, branched, rooted
by a creeping tubular fibre ; branches tubu-
lar ; polypes existing at the extremities of
the branches, ovoid, the mouth at the distal
extremity, and furnished with scattered fili-
form tentacula.

C. lacustris, the only species; height 2-3
inches. The only compound Polype found
in fresh water.

BIBL. Allman, Ann. N. H. xiii. 330; and
Phil. Tr. 1853; Johnston, Br. Zoophytes,
44 ; Hincks, Zooph. 15 5 Schnitzels Archiv,
1871.

CORE'MIUM, Link. — A spurious genus
of Mucedines (Hyphomycetous Fungi), not
really distinct from PENICILLIUM ; but dif-
fering from the characteristic form of that
genus in having the erect fertile filaments
compacted into a kind of cellular pedicle to
bear the strings of spores (fig. 142). C. leu-
copus, Pers. ; filaments white, spores green ;
not uncommon on decaying fruits, &c.=

Floccaria glauca, Grev. Sc. Crypt. Fl. i. 301,
and is Penicillium crustaceum /3, Fries. C.
candidum, Nees, filaments and spores white,

Fig. 142.

Coremium niveum, Corda.
Magnified 200 diameters.

on decaying substances, is Penicillium can-
didum /3, Fries.

BIBL. Hook. Brit. FL v. pt. 2. 344;
Fries, Syst. Mycol iii. 408 ; Greville, loc. cit. j
Corda, IconesFung.\\. pi. 11. fig. 73; Pracht-
flora, pi. 25.

CORE'THRA, Meig.— A genus of Dip-
terous Insects, of the, family Tipulidse.

The larva of C. plumicornis forms a beau-
tiful microscopic object; it inhabits fresh
water.

BIBL. Karsch, Monog. d. Coreth. plum. ;
Ray Lankester, Pop. Sc. Rev. 1865 ; Ley-
dig, Sieb. $ Kott. Zeitsch. iii. 435 ; Rymer
Jones, Mic. Tr. 1866. 99 ; Weismann, Sieb.
$ Koll. Zeitsch. 1866, 45.

CORE'THRIA, Wright.— A genus of
Rhizopoda, family Actinophryina (?). Body
oblong, with a long club-shaped appendage,
bearing a thick brush of 8-40 tentacles at
its summit.

C. sertularia. On Sertularia pumila.

BIBL. Pritchard, Infus. p. 563.

CORWNA, Heib— A genus of Diato-
maceae.

Char. Frustules punctate-areolate, united
into semicircular fasciae, angles produced,
spiniferous, the uppermost longest, inter-
mediate portion hemispherical, with septa ;
valves ellipsoidal, transversely bicostate,
apiculate at each end.

CORK.

[ 210 ] CORPORA AMYLACEA.

C. ekgans. Shores of Denmark.

BIBL. Heiberg, Consp. Diat. 1863, 63,
pi. 3. tig. 8.

CORK. — Ordinarily the outer layer of
bark of the Cork Oak (Quercus Suber\ for
the development of which, see BARK. Ver-
tical and transverse sections of the large
light-coloured cells of cork are shown in
PL 47. figs. 16 and 17. The term cork is
applied generally to excessive developments
of the suberous layer of barks.

CORN. — The general name applied to
the seeds, or rather the fruits of the various
plants furnishing the ordinary materials for
bread. These all belong to the Monocoty-
ledonous family, Graminacese (Grasses) ; for
Buck-wheats cannot be considered as true
corn. The grains of the Grasses are enve-
loped in the adherent pericarp, which is dry
and smooth ; the seed which this encloses is
characterized by the presence of a compara-
tively larger mealy albumen, composed of
thin- walled parenchyma, more or less densely
filled with starch, which makes up the great
body of the grain ; a few layers of cells sub-
jacent to the surface, however, contain little
starch, but abundance of nitrogenous proto-
plasmic matter, or gluten. These layers
containing the greater proportion of the
gluten, together with epidermis, are removed
from fine flour in grinding, as the bran and
pollard — the fine white flour consisting
chiefly of the starch. The forms of the
starch-grains differ considerably, as also
their condition in the cell (PI. 46). In
Wheat (Tritieum), the starch-grains are
lenticular (fig. 8), and lie loose in the cells ;
in Barley (Hordeuni), they are very similar,
but the larger grains are squarish and
thinner (fig. 9) ; in Oats (Avena), polygonal,
but compacted together into roundish
masses (fig. 10) ; in Rice ( Oryza), the starch-
grains are very small, and packed so
closely together that they press upon one
another, thus acquiring a parenchymatous
form (figs. 12 & 13) ; and then, as they ad-
here firmly together, the contents of the cells
appear like one solid mass ; hence the horny
character of the grains of rice, and the grit-
tiness of rice-flour. In Maize (JZea), the
outer part of the grain is horny from the
same cause as rice, and presents a similar
appearance (fig. 3), but in the centre the
cells are often less densely filled, and the
grains lie more or less loose (fig. 5). For
further particulars of the characters of
the starch-grains, see STARCH.

CORNEA. See EYE.

CORNICULA'RIA, Ach.— A genus of
Lichens —Akctoria pt.

CORNS consist of thickened epidermis,
the scales being increased in number, much
flattened, and closely aggregated from pres-
sure. This is the structure in their simplest
form. When larger they represent an ordi-
nary blister, conjoined with the thickening
of the epidermis ; hence the origin of the
cavity in the centre of many of them. The
papillae of the cutis are generally hypertro-
phied. The epidermic scales may be ren-
dered distinct by digestion with acetic acid
or solution of potash.

CORNUSPI'RA, Schultze.— This genus,
restricted, comprises the planorbiform Mtti-
olida, which, commencing with a somewhat
agathistegian growth, soon become discoi-
dal and non-segmented.

C.foliacea (PI. 23. fig. 13) is a common
Foraminifer, white and opaque, with the
whorls rapidly increasing in width in the
adult state. It has abounded from the
older Tertiary times to the present, chiefly
in shallow water, but found at 530 fathoms,
North Atlantic, by Carpenter.

BIBL. Carpenter, Foram. 68; Pr. Roy.
Soc. 1869 j Schultze, Ann. N. H. 1861,
306.

CORT9RA AMYLA'CEA.— These are
microscopic rounded bodies, exhibiting a
number of concentric rings, and somewhat
resembling starch-grains in appearance.

They are found in
the forniz,t}ie septum Fig. 143.

lucidum, the walls of
the ventricles, and the
cortical substance of
the brain, the me-
dullary substance of ^
the spinal cord, the M ified 350 diameter8.
waxy spleen &c. Corpora lacea> from

Ihey are but little the human ependyma.

acted upon by dilute

acids; caustic alkalies render them more
transparent, and gradually dissolve them.
Solution of iodine gives them a bluish tinge ;
and the subsequent addition of sulphuric
acid produces the bluish- violet colour seen
when cellulose is treated with these reagents.
The reaction is best seen when the action of
the acid takes place slowly. Hence these
bodies have been regarded as consisting of
amyloid or cellulose.

The corpora amylacea must be distin-
guished from the concretions forming ' brain-
sand,' or the acervulus cerebri. These are
also rounded, single, or aggregated, usually

COKPUSCTJLA.

211 ]

COSCINODISCUS.

exhibiting the concentric rings, sometimes
forming cylindrical, ramified, or reticular
fibres. They are met with in the choroid
plexuses, the pineal gland, the arachnoid
membrane, and sometimes in the walls of
the ventricles. These consist of an organic
(proteine) skeleton, containing carbonate
and phosphate of lime. When treated with
acids, the latter are dissolved, the former
being left and retaining the original form of
the concretions.

BIBL. Purlrinje, Miilkr's Archiv, 1836 &
1845 ; Kolliker, Mikr. An. ii. ; Virchow,
Archiv path. An. 135, 268, 416, and Ann.
N. Hist. xii. 481 ; Green, Pathology, 1871,
71 ; Frey, Histol. ; Kindfleisch, Path. 1878,
35.

COKPUS'CULA, of the Conifera. See
GYMNOSPEBMIA.

CORROSIVE SUBLIMATE, the bichlo-
ride of Mercury. — A saturated solution of
this salt is very useful in rendering very
transparent bodies consisting of proteine-
compounds more opaque and distinct, as
the bodies and cilia of Infusoria &c.

CORYCJ5'US, Dana.— A genus of Cope-
poda (Entomostraca).

C. anglicus. Marine.

BIBL. Brady, Copepoda {Ray /Sbc.), iii.

on

CORY'CIA, Duj. = Amoeba Ulimbosa,
Auerbach (Duj. Ann. d. Sc. N. 1852, p. 41).

CORYMOR'PHA, Sars.— A genus of
marine Hydroid Polypi, family Tub ulariidae.

BIBL. Hincks, Brit. Zooph. p. 125.

CORYNACTIS, Allrnan.— A genus of
Anthozoa (Zoophytes).

1 species : C. viridis.

BIBL. Gosse, Actinologia Britannica (the
latest work on Sea- Anemones).

CORY'NE, Gsertn. — A genus of marine
Hydroid Polypi, family Corynidse.

BIBL. Hincks, Brit. Zooph. p. 37.

CORYN'ETJM, Kunze.— A genus of Me-
lanconiei (Stylosporous Fungi), consisting
of parasitic plants growing upon dead twigs,
bursting out as convex solid pustules from
beneath the epidermis. A vertical section
of half of one of these pustules is shown
in fig. 144; the cellular stroma is covered
by stalked multiseptate spores. Six forms
are recorded as British. That figured,
C. disciforme, Kze., grows on dead twigs of
birch.

Tulasne states this genus to consist of the
conidiiferous form of Melanconie i (Sphseria-
cei).

BIBL. Hook. Br. FL v. pt. 2. 355;

Fig. 144.

Berk. & Broome, Ann.
N. H. 2 ser. v. 458;
Currey, Qu. Mic. Jn. v.
127 ; Tulasne, Ann. Sc.
Nat. 4 ser. v. 110;
Corda, Icones Fung.

COR YNO'PSIS, All-
man. — A genus of ma-
rine Hydroid Polypi,
family Hydractiniidse.

C. Alderi. Durham.

BlBL. Ilincks, Brit. Coryneum disciforme.
Zooph. p. 34. Vertical section of half

COSC1NODISCUS,
— Ehr. A genus of
Diatomaceae.

Char. Frustrates free, single, disk-shaped;
valves circular, flat, or slightly convex, ex-
hibiting a cellular or areolar appearance ;
no internal septa, nor lateral processes.

The cellular appearance arises from the
existence of depressions, which are of
different sizes. The valves form beautiful
objects.

Kiitzing enumerates forty-one species,
which are either marine or fossil. Smith
admits four British species.

C. minor, E. Depressions irregular and
crowded (circular, Sm.) ; margin of valves
smooth ; freshwater and marine ; diam.
1-1200 to 1-500".

C. radiatus, E. (PI. 61. fig. 1). Depres-
sions obscurely radiating, marginal ones
smallest ; margin of valves smooth ; marine
and fossil ; diani. 1-550 to 1-180" (a, side
view; b, front view).

C. eccentricus, E. Depressions arranged
in curved lines, with the convexity towards
the centre ; marine and fossil ; diam. 1-400
to 1-200".

C. pyxidicula, Kg. (Pyxidicula and Cras-
pedodiscus coscinodiscus, E.) (PI. 18. fig. 21).
Margin tumid, elegantly cellular, central
areola very fine, diminishing towards the
centre ; no umbilical star ; marginal cells
hexagonal, larger ; diam. 1-400". Fossil.
Virginia.

C. craspedodiscus, K. = Craspedodiscus ele-
gans, E. (PL 25. figs. 7, 8). Margin of
valves tumid, elegantly sculptured, central
markings radiating ; an umbilical star
formed of 5 to 6 oblong larger cells ? ;
diam. 1-120'[. Fossil. Bermuda.

C. oculus iridis. Areolae hexagonal, with
central " eye-spots."

BIBL. Ehr. Abhandl. Berl. Ak. 1838 and
1839 ; id. Ber. Berl. Akad. 1840 et seq. ;
Kiitzing, BacilL and Sp. Alg. ; Smith,
r2

COSCINOSPIRA.

[ 212 ]

COTTON.

Brit. Diat. I ; Wallich, Qu. Mic. Jn. 1860,
38; Greville, Mic. Trans. 1864, 9; 1865,
25, 43 ; 1866, 3, 78.

COSCINOSPI'RA, Ehrenberg. — The
elongate subtype of Peneroplis, one of the
Foraminifera imperforata. It is a synonym
of Spirolina, Lamarck.

BIBL. Ehrenberg, Tr. Berlin Ac. 1839 ;
Parker and Jones, Ann. N. H. ser. 3, v. 180.

COSMARIUM, Corda.— A genus of Des-
midiacese.

Char. Cells single, constricted at the
middle; segments as broad as or broader
than long, neither sinuated nor spinous.

A peculiar swarming motion is observ-
able at times in the cell-contents of this
genus, different from the circulation in
Closterium. From some observations by
Mrs. Thomas, it appears that the spore-cell
divides into numerous individuals in ger-
mination.

Rabenhorst describes 77 European species.
Among the most common British species
are : —

C. pyramidatum (PI. 14. fig. 18, 19 empty
cell). Oval, with depressed and truncate
ends, deeply constricted ; end view ellipti-
cal ; segments punctate, entire ; length
1-470 to 1-260".

C. bioculatum. Smooth, depressed, con-
striction producing a gaping notch on each
side ; end view elliptical ; segments subel-
liptic, entire; sporangium orbicular, spi-
nous ; length 1-1410".

C. crenatum (PI. 14. fig. 20). Punctate,
deeplv constricted ; segments crenate at the
margin, depressed at the end; end view
elliptical ; spines of sporangium very short;
length 1-470".

C. tetraophthalmumCPLU.&g.W). Deeply
constricted ; segments semicircular ; end
view elliptical ; rough with pearly granules,
which give a crenate appearance to the
margin ; length 1-230".

C. margaritiferum (PI. 14. fig. 21).
Rough with pearly granules, which are as
broad as long ; end view elliptic ; segments
semicircular or reniform ; length 1-560 to
1-300".

C. ornatum. Segments twice as long
as broad, rough with granules giving a
dentate appearance to the margin ; end view
with a truncate projection on each side;
length 1-610".

C. cucurbita. Punctate, constriction slight,
ends rounded; transverse view circular;
length 1-580".

Lob b describes an extraordinary species,

C. radiatum, the surface being covered by
densely crowded hyaline filaments, like
those of Actinophrys, but closer.

BIBL. Ralfs, Desmid. 91 & 212 ; Thomas,
Mic. Tr. new ser. iii. 33 ; Lobb. Qu. Mic. Jn.
1866, 55 ; Archer, Qu. Mic. Jn. 1860, 235,
1864, 178.

COSMIODIS'CUS, Grev.— A genus of
fossil Diatomacea9.

Char. Frustules simple, disk-shaped;
valves radiato-punctate or areolar, with
linear radiating spaces (no processes nor
internal septa). 3 species: in Monterey
and Barbadoes deposit.

BIBL. Greville, Qu. Mic. Jn. 1866, 79.

COSMOCLA'DIUM, Br^b.— A genus of
Desmidiaceae (Palmellaceae, Rab.).

Char. Cells rounded, compressed, deeply
constricted, attached to a branched stipes.
Reproduction by gonidia.

C. jmlchellum (PI. 61. fig. 38), attached ;
in turfy pools.

2 other species (unattached).

BIBL. De Bre"bisson, Liste d. Desm. 133;
Rabenhorst, Fl. Alg. iii. 53.

COTHURNIA, Ehr.— A genus of Infu-
soria, of the family Vorticellina, subfamily
Ophrydina.

Char. Solitary; carapace urceolate,
stalked, fixed by the posterior extremity.

An anterior ring of cilia is present. The
body contracts suddenly, like that of Vorti-
cetta.

Dujardin unites this genus with Vagini-
cola.

C. imberbis, E. (PI. 32. fig. 20). Stalk
much shorter than the hyaline carapace ;
body yellowish ; aquatic ; length of carapace
1-280". Found upon Cyclops quadricornis.

C. maritima, E. Stalk much shorter
than the carapace ; body whitish, hyaline ;
length of carapace 1-570". On Ceramium.

C. havniensis, E. Stalk much longer
than the carapace ; body whitish; length of
carapace without the stalk 1-280", stalk
twice this length. On Sertularice &c.

Stein adds 3 species, C. Sieboldii, C.
astaci, and C. curva ; found upon Astacus
flumatilis (the Cray-fish), Cl. & L. de-
scribe 12 species, 4 new,

BIBL. Ehr. Inf. 297; Duj. Inf. 564;
Stein, Infus. ; Clap. & Lachm. Infus. i.
121 ; Kent, JTw/. 719 ; Hutton, Jn. Mtc. Soc.
1878, i. 49.

COTTON.— The hairs from the epidermis
of the seeds of various species of Gossypium
(Malvaceae, Dicotyledons). These hairs are
readily distinguished under the microscope

COVERS.

C 213 ]

CRIBRARIA.

from the various textile fibres consisting of
liber structures. From the absence of the
regular thickening layers, the cells of the
cotton-hairs become collapsed when dry,
appearing like a flat band with thickened
borders, while liber-cells of all kinds re-
main cylindrical, and taper to a point at
each end (PI. 28. fig. 1). See FIBROUS
STRUCTURES ; and Mitchell, Qu. Mic. Jn.
1864, 218.

COVERS. See INTRODUCTION, p. xxiv.

CRASPEDODISCUS, E.— A genus of
fossil Diatomaceae.

C. Coscinodiscus, J&.za PyxicKeuIa Coscino-
discus, E. = Coscinodiscus pyxidicula, Kg.
(PL 18. fig. 21).

C. elegans, E. = Coscinodiscus craspedodis-
cus, Kg. (PL 25. figs. 7 & 8).

BIBL. Ehr. Ber. d. Berl Ak. 1844, 261-
266 ; Kiitzing, Sp. Alg. 126 ; Greville, Mic.
Trans. 1866, 79; Pritchard, Inf. 831, 939.

CRASPEDO'PORUS, Grev.— A genus
of Diatomacese.

Char. Frustules free, disk-shaped ; valves
with club-shaped rays, each with an ocellus
near the margin.

C. Ralfsianus. Valves areolar, rays 8;
diam. 1-220". Barbadoes.

C. Johnstonianus. Rays 5 ; diam. 1-400".
Barbadoes.

BIBL. Greville, Mic. Trans. 1863, 68.

CRATERIUM, Trent.— A genus of
Myxomycetes, consisting of minute yellow
or brown cup-like bodies, of papery con-
sistence, closed by a deciduous operculum
(fig. 145); arising
from an evanes-
cent gelatinous
mycelium, grow-
ing over moss,
leaves, bark, &c.
Most of the spe-
cies are common.
The black spores
contained within
these cups are
intermixed with crowded, obscurely arti-
culated filaments (destitute of spiral "fibres),
which do not anastomose, and are at length
erect. Five British species. A. Murray's
remark upon Craterium, that it is an
Acarus, applies to Atractobolus.

BIBL. Hook. Brit. Fl v. pt. 2. 316;
Sowerby, Fungi, t. 239 (C. minutum, as
Cyaihus minutus).

CRATEROSPER'MUM, Braun.— A ge-
nus of Zygnemacese, with the green endo-
chrome not in spiral bands. Conjugating

Fig. 145.

Craterium pyriforme.
Magnified 10 diameters.

filaments geniculate ; sporange or zygospore
with a double cyst ; the inner spherical, the
outer thick, shortly cylindrical, subquad-
rate, with an annular furrow, and ex-
cavated at each pole.

C. Icetemrem (PL 3. fig. 10). In pools.

BIBL. Braun, Alg. Unicell. 1855, 60;
Rabenhorst, Fl Alg. iii. 258 (fig.).

CREATINE or KREATINE.— Occurs
in the juice of the flesh of Mammals, Birds,
Amphibia, and Fishes ; in exudations, in the
amniotic liquid, the blood, and the brain.
It crystallizes from an aqueous solution, in
transparent, highly refractive, oblique-rhom-
bic prisms and needles (PL 11. fig. 22) be-
longing to the oblique-rhombic prismatic
system.

CREATININE or KREATININE.—
Occurs in the urine of man and of Mam-
malia. The crystals form colourless prisms
belonging to the oblique -rhombic prismati
system (PL 11. fig. 23).

Creatinine forms a crystallized compound
with chloride of zinc (PL 1 1. fig. 24) . Thi s
is verv difficultly soluble in water, and not
at all in alcohol or ether.

CRE'NOTHRIX, Cohn.— A genus of
Oscillatoriaceae (Confervoid Al^ae).

Char. Filaments narrow, jointed, ar-
cuate or twisted into little free or ad-
herent tufts ; with hyaline sheaths ; endo-
chrome homogeneous ; sporanges terminal.
Microgonidia formed from a row of cells by
successive division, rounded, very minute,
crowded, and without cilia. Macrogonidia
of the entire or 2-4-divided ceU"Contents.
Intermediate between Lyngbya and C/<«-
mfssiphon.

C. polyspora. In wells and springs.

BIBL. Cohn, Beit. Biol. i. 108.

CRESS WEL'LIA, Grev.— A genus of
fossil DiatomaeesB.

Char. Frustules cylindrical, cohering by
short filiform (spine-like) processes into a
continuous filament. Valves cup-like, are-
olar, destitute of siliceous connecting band
or hoop.

C. turris. Clyde. Other species.

BIBL. Greville, Win. Ph. Tr. 1857, xxi.
538; Mic. Tr. 1861, 68; 1865, 4; 1866,
78.

CRIBRA'RIA, Schrad.— A genus of
Myxomycetes (Gasteromycetous Fungi),
consisting of minute stalked capsules grow-
ing upon rotten wood &c. The capsules
(peridia) are membranous; the upper part
falls or decays off when the spores are
mature j and the anastomosing filam n ts

CRIBRILINA.

[ 214 ]

CRONART1UM.

Cribraria aurantiaca.
Natural size.

Fig. 147.

(capillitium) which are contained in the in-
tenor, are confluent with the outer wall,
where they torm a permanent spherical
cage or network (fig. 147), from the meshes
of which the spores escape. The three or
four species recorded as British, are C.
intermedia, Berk.,
intermediate be- Fig. 146.

tween C. vulgaris
and C. aurantiaca.
The peridium is
yellow with a white
stalk; the spores
yellow. (Figured
as Sphterocarpits
semitrichioides by
Sowerby, t. 400.
fig. 5.) To this
have recently been
added C. argilla-
cea, aurantiaca, and
intricata. They are
very interesting
microscopic ob-
jects.

BIBL. Hook.
Brit. Fl v. pt. 2.
318; Fries, Syst.
Mycolog. iii. 168;
Corda, Icon. Fung.
v. pi. 3. fig. 35;
Cook, Handb. 400.
CRIBRILI'NA,
Gray. — A genus
of Cheilostomatous
Polyzoa(BryOZOa), Peridium burst, with the ca-
= Lepralice with »0»fc» exserted.

the front CeUs OC- Magnified 25 diameters.

cupied by transverse or radiating punctured
furrows. 5 species. On shells and Algse.

BIBL. Hincks, Polyzoa, 184.

CRICKET. See ACHETA.

CRIS'IA, Lamx. — A genus of Crisiidae,
Cyclostomatous Polyzoa.

Char. See CRISIID^E. Three species.

C. cornuta. Cells curved, orifices turned
one way ; a long bristle above each cell.

C. eburnea. Cells loosely aggregated,
curved, ends free. Common.

C. denticulata. Cells loosely aggregated,
nearly straight, joints black.

CRISIIDAE.— A family of Cyclosto-
matous Polyzoa.

Distinguished by the plant-like jointed
and branched calcareous polyzoary and the
tubular cells in one or two rows, with
round orifices mostly looking to opposite
sides.

Cribraria aurantiaca.

Cells and branches covered with dots
Pear-shaped vesicles are met with on the
polypidom, resembling those of the Sertu-
lariiasB.

Crisia. Cells in one or two rows, sub-
alternate ; orifices terminal and entire.

BIBL. Johnston, Sr. Zuoph. 382 ; Hincks,
Polyzoa, 418.

CRISTATEL'LA, Cuv.— A genus of
CristatellidaB, Polyzoa (Bryozoa).

Char. Polyzoary free, disk-shaped, poly-
piferous at the margin ; tentacles numerous,
pectinate upon two arms. Freshwater.

C. mucedo (PI. 41. fig. 9). Three, four,
or more polypes arise from the locomotive
polypidom. Pseud-ova (stato blasts) in the
young state enclosed in a ciliate membrane,
disk-shaped, furnished with marginal spines
which are hooked at the end (fig. 10), and
opening with a lid.

In clear lakes and ponds, creeping over
stones and the stems of aquatic plants ; and
occasionally in large numbers in the holes
made by the feet of cattle around ponds.
Length 1£", breadth £".

BIBL. Cuvier, Regne Animal, 1817, iv.
68 ; Turpin, Ann. d. Sc. Nat. 2 se"r. vii. 66 ;
Gervais, ibid. vii. 77 ; Johnston, Br. Zooph.
387; Varley, Lond. Phys. Journ. iii. 37;
Allman, Polyzoa. (Ray Soc.).

CRISTELLA'RIA, Lamk.— Among the
hyaline Foraminifera grouped generically
as Nodosarina and varying in mode of
growth from straight and partially curved
to discoidal, the Cristdlarice are the more
symmetrically lenticular and nautiloid, vary-
ing, however, in outline and in thickness.
The chambers, either triangular or falciform,
are close-set and communicate at the outer
angle. The shell is neat, often delicate,
and ornamented on the margin with keel or
crest, and on the sides with raised umbones,
granulations, cross bars, and septal ridges.

Cristettaria is common in the Lias and
all succeeding formations, very large in the
Tertiary deposits of Italy, and not uncom-
mon in existing seas. C. simplex (PI. 23.
fi^. 34), feeble of growth, is present always
with other Cristellarice. C.cultrata(fig.37)
is a well-grown and typical form.

BIBL. D'Orbigny, For. Foss. Vien. 82;
Morris, Brit. Foss. 33; Williamson, Rec.
For. 24 ; Parker and Jones, Ann. N. H.
2 ser. xix. 209;. 3 ser. iii. 477; v. 114; Car-
penter, For am. 162.

CRONAR'TIUM, Fries.— A genus of
Uredinei (Coniomycetous Fungi), present-
ing the most perfect form of structure in

CROUANIA.

C 215 ]

CRUSTACEA.

that family. The spores are contained in
a peridium, which bursts by a regular or
irregular apical orifice. The perfect spores
are produced on a columnar cellular body,
called the ligule, which rises out of the
centre of the Uredo-form or of its empty
perithecium. C. Vincetoxid is the perfect
form of Uredo Vincetoxici.

BIBL. Tulasne, Ann. Sc. Nat. 4 ser. ii.
188.

CROUA'NIA, J. Agardh.— A genus of
Cryptonemiaceae (Florideous Algae). C.
atienuata is a very rare plant, which has
been found epiphytic on Cladostephus spon-
giosus. Its frond consists of a single-tubed
jointed filament, with the joints clothed
with dense whorls of minute dichotomously
multiplied branchlets, somewhat beaded.
The favellidia are stated to occur near the
tips of the branchlets; the tetraspores (large)
are affixed to the bases of ihe latter.

BIBL. Harvey, Mar. Alg. pi. 21 D ; Phyc.
Brit. pi. 106 ; J. Agardh, Alg. Medit. 83 ;
Agardh, Sp. Alg. ii. 136 (as Griffiihsia
nodulosa) ; Kiitzing, Sp. Alg. 651 ( Calli-
thamniori).

CRUCIB'ULUM, Tulasne.— A genus of
Nidulariacei (Gasteromycetous Fungi).

C. vulgare occurs frequently on ferns, de-
cayed sticks, &c., and is found in many
parts of the world.

BIBL. Sachs, Sot. Zeit. xiii. 833: Tulasne,
Ann. Sc. N. 1844.

CRUCILOCULI'NA, D'Orb.— A Trilo-
culine Miliola with a crucial fissure for its
aperture — that is, having four small symme-
trical valves, instead of one. Known only
from the Patagonian coast.

BIBL. D'Orb. For. Amfr. Mer. 1839 j
Carpenter, Introd. For. 80.

CRUME'NULA, Duj.— A genus of In-
fusoria, of the family Thecamonadina.

Char. Oval, depressed, with a resisting
obliquely striated or reticulated tegument,
from a notch in the fore part of which a
long flap:elliform filament issues ; a red eye-
spot. Movement slow.

C. testa (PI. 30. fig. 34). Green ; aquatic;
length 1-510". Filament three times as long
as the body.

Dujardin appends Prorocentrum, E., to
this genus.

BIBL. Dujardin, In/us, p. 339.

CRUOR'IA, Fries. — A genus of Crypto-
nemiacese (Florideous Algae). C. pellita is
common on exposed rocks and stones be-
tween tide-marks, forming a glossy purplish
skin, between gelatinous and leathery, upon

smooth surfaces, in patches 2 to 3" in dia-
meter. This ' skin' is formed of vertical tufts
of simple articulated filaments imbedded
in a gelatinous matrix. One of the cells of
each filament is larger than the rest. The
tetraspores occur at the bases of the fila-
ments.

BIBL. Harvey, Mar. Alg. pi. 20 C ; Phyc.
Brit. pi. 117.

CRUSTA'CEA.— A class of Animals,
belonging to the subkingdom Articulata.

Char. Apterous ; no tracheae ; respira-
tion aquatic (branchial), or effected by the
skin : legs jointed. A dorsal vessel, ven-
tricle, or heart; integument composed partly
of chitine.

The integument of the Crustacea usually
forms a hard calcareous shell, sometimes,
however, being leathery or horny ; it con-
stitutes an external skeleton. In its most
complex condition four layers are distin-
guishable : — an outermost, very thin, trans-
parent, and structureless or cellular — the
epidermis; beneath this, a layer of pig-
ment-cells to which the colour is owing, but
sometimes the pigment is not contained
within cells; under this is a thick layer,
forming the greater part of the substance of
the integument, impregnated with calca-
reous salts, and frequently furnished with
direct prolongations in the form of tubercles,
spinous appendages, or hairs. See SHELL.
The innermost layer consists of a delicate
fibrous coat, corresponding to an internal
periosteum or true skin ; it plays an im-
portant part in the moulting process (ecdy-
sis) which the Crustacea undergo, probably
secreting the new layers of the integument.
The higher Crustacea (the Decapoda)
have mostly two pairs of antennae.

The oral organs consist of a transverse
labrum or upper lip ; beneath which is a pair
of powerful toothed mandibles, acting late-
rally, and furnished with palpi. Next come
two pairs of maxillae ; the first are membra-
nous and hairy at the margin, but without
palpi ; the second are also membranous and
hairy, and correspond to the labium of In-
sects. Between the mandibles and the first
pair of maxillae is sometimes situated a soft,
tongue-like, sometimes cleft appendage.
The oral organs undergo various modifica-
tions in the lower Crustacea ; these will be
considered under the respective heads. Be-
hind these are three pairs of secondary or
auxiliary jaws, or rather legs converted into
jaws, and comparable to the six legs of In-
sects ; these are furnished externally with

CKUSTACEA.

[ 216 ]

CRYPTOMONADINA.

palpi. Next follow five pairs of true tho-
racic legs, behind which are five pairs of
false or abdominal legs.

The voluntary muscles of the Crustacea
are transversely striated.

The eyes are either simple : consisting of
a convex cornea, behind which is a rounded
refracting body or lens ; this lies in a cup-
shaped mass of pigment, perforated by the
optic nerves ; — compound without facets :
consisting of a smooth cornea, behind which
a number of closely-placed eyes are situ-
ated ; sometimes a modification of this form
occurs, in the existence of a smooth outer
and an inner faceted cornea ; — or compound
faceted : as in the eyes of insects. The
facets are frequently four-sided, but some-
times six-sided. In some of the eyes a
conical vitreous body is situated behind the
lens. The eyes are sometimes sessile, at
others stalked.

The alimentary canal is usually short and
nearly straight, sometimes curved or coiled.
Its wall consists of three or four layers, —
the outermost, more or less fibrous, repre-
senting a peritoneal coat j the innermost, a
transparent, structureless, epithelial coat,
furnished at the part corresponding to 'the
stomach with calcareous teeth, scales, or
hairs, and which is thrown off during the
ecdysis. Between these two coats is a layer
of smooth muscular fibres.

The liver exists either in the form of sim-
ple follicles surrounding the alimentary ca-
nal ; of branched caeca situated at its upper
end, sometimes with short ducts ; or as two
glandular tufts or branches, consisting of
more or less ramified and closely-connected
caeca, with short ducts.

In many of the Crustacea the walls of the
alimentary canal are surrounded by cells
containing a bright orange-yellow or blue
fatty matter ; these are either scattered or
arranged in the form of lobules. They cor-
respond to the fatty body of Insects.

The Crustacea undergo remarkable meta-
morphoses, the larvae differing strikingly
from the adults ; and to these, special names
were applied, being considered as distinct
genera : as Nauplius, Zoea, and Megalopa.

See ASELLUS, CIRRIPEDIA, ENTOMOS-
TRACA, GAMMARUS, ONISCUS, and SIPHO-

NOSTOMA.

BIBL. That of ANIMAL KINGDOM, and
the Bibl. of the articles just cited ; Gegen-
baur, Vergl Anat. 247; Schultze (eyes), Qu.
Mic. Jn. 1868, 173 ; Chatin, Compt. JRend.
1876, Ixxxiii. 1052 (M. M. Jn. xvii. 92) ;

Bell, Stalk-eyed Brit, (figs.) ; Bate and West-
wood, Sessile-ei/ed.

CRYPTOCOC'CE^E.— OneofKiitzing's
families of Algae, including his genera Cryp-
tococcus, Ulvina, and Sphferotilus, all of
which appear to be forms of the mycelia
(conidia ?) of Mildew Fungi ; they consist
of masses of extremely minute colourless
globules, aggregated into a membranous or
mucous stratum, and found floating in
aromatic waters, vinegar, &c.

CRYPTOCOC'CUS, Kutz. See CRYP-

TOCOCCEJE.

CRYPTOGA'MIA.— This term was ap-
plied by Linnaeus to his 24th Class, which
included all plants in which no true flowers
exist ; the name signifying that the sexual
organs are hidden. In Natural Arrange-
ments of the Vegetable Kingdom the term
is often used in the same sense ; but in this
case as one of two great divisions, being
opposed to Phanerogamia or Phaenogamia,
which are plants with the sexual organs
conspicuous. See VEGETABLE KINGDOM.

CRYPTOGLE'NA, Ehr.— A genus of
flagellate Infusoria, of the family Crypto-
monadina.

Char. Free ; a red eye-spot ; carapace a
scutellum, rolled in at the margins, without
a neck. Freshwater.

C. conica (PI. 30. fi^. 35 a). Conical,
expanded, and truncate in front, posteriorly
subacute ; bluish green ; length 1-1150";
two flagelliform filaments.

C.pigra (PL 30. %. 35 b). Ovato-sub-
globose, emarginate in front ; green ; length
1-1150". (Chloromonas, Kent.) Motion
slow ; filament single.

C. ccerukscem. Elliptic, depressed, emar-
ginate in front ; bluish green ; length 1-6000";
motion rapid ; no cilia distinguished.

Carter adds 3 species.

BIBL. Ehr. In/us. 46 ; Duj. In/us. 333 ;
Carter, Ann. N. H. 1858, ii. 253; 1859, iii.
18 ; Pritchard, Infm. 509 ; Kent, Inf. 419.

CRYPTOGRAM'MA, Brown.— A genus
of Pterideae (Polypodiaceous Ferns).

Char. Sterile and fertile fronds usually
different; sori terminal on the veins, at
first separate and rounded, then confluent;
indusium formed of the involute margin of
the frond.

C. crispa. British.

BIBL. Hooker, Syn. Fil 144.

CRYPTOMONADI'NA, Ehr.— A family
of Infusoria.

Char. An envelope or carapace, either

CEYPTOMONAS.

[ 217 ]

CRYPTONEMIACE^E.

soft or hard ; no appendages (organs of mo-
tion, D.) except anterior cilia, or one or
more flagelliforin filaments j form constant.
(Envelope insoluble in potash ?)

These organisms do not admit colouring-
matters, hence they should probably be re-
ferred to the Algsd. One or more cilia or
flagelliform filaments have been detected in
all the genera but one (Lagenella).

The family corresponds very nearly with
the Thecamonadina of Dujardin.

No eye-spot.
Carapace with a distinct tooth, in front Prorocentrum.

Carapace without a tooth Cryptomonas.

Eye-spot present.

Carapace with a neck Lagenella.

Carapace without a neck : —

Carapace a scutellum. Cryptoglena.

Carapace not a scutellum Trachelomonas.

Dujardin adds the genera Phacus, D. (in-
cluding Euglena, E. in part), Crumenula, D.,
Diselmis, D., Clamidornonas,l&.,Plceotia,~D.,
Anisonema, D. (including Bodo grandis, E.,
and Oxyrrhis, D.= Prorocentrum: E.)j and
appends doubtfully Chcetoglena, E., and
Chcetotyphla, E.

See THECAMONADINA, OPHIDOMONAS, and
PROTOCOCCUS.

BIBL. Ehrenb. In/us. 38 ; Duj. Infus. 323.
CRYPTOMONAS, E.— A genus of In-
fusoria, of the family Cryptomonadina.

Char. No eye-spot ; carapace without an
anterior tooth. Dujardin says : Globular or
slightly depressed ; secreting a membranous
flexible carapace, and furnished with a very
delicate flagelliform filament.

Ehrenberg admits seven species ; and to
these Dujardin adds two.

C. ovata, E. (PI. 30. fig. 36 a) ; length
1-570" ; freshwater.

C. lenticularis, E. (PI. 30. fig. 36 6) ; length
1-1730" ; freshwater.

C.fusca, E. (PI. 30. fig. 36 c) j length
1-1500"; freshwater.

C. globulus, D. (PI. 30. fig. 36 d) ; length
1-2500" ; freshwater.

C. inaqualis, D. (PI. 30. fig. 36 e) ; length
1-2500" ; freshwater.

Dujardin appends Cryptoglena, E., and
Lagenella, E., to this genus.

BIBL. Ehr. Inf. 40 ; Dujardin. Inf. 329:
Kent, Inf. 404.

CRYfcTONEMIA'CELE.— A family of
Florideae. Purplish or rose-red sea-weeds,
with a filiform or (rarely) expanded, gela-
tinous or cartilaginous frond, composed
wholly or in part of cylindrical cells con-
nected together into filaments. Axis formed
of vertical, periphery of horizontal radiating

filaments. FRUCTIFICATION: — 1. Concep-
tacles (favellidia), forming globose masses of
spores immersed in the frond or in swell-
ings of the branches. 2. Tetraspores variously
dispersed. 3. Antheridia (Nemaleori).

Subtribel. COCCOCARPEJE. Frond solid,
dense, cartilaginous or horny. Favellidia
contained in semi-external tubercles or swell-
ings of the frond.

Grateloupia. Frond pinnate, flat, nar-
row, membranaceo-cartilaginous, of^ very
dense texture. Favellidia immersed in the
branches, communicating with the surface
by a pore. Tetraspores scattered.

Gdidium. Frond pinnate, compressed,
narrow, horny, of very dense structure.
Favellidia immersed in swollen ramuli.
Tetraspores forming subdefined son in the
ramuli.

Gigartina. Frond cartilaginous, cylin-
drical or compressed ; its flesh composed
of anastomosing filaments, lying apart in
firm gelatine. Favellidia contained within
external tubercles. Tetraspores massed to-
gether in dense sori, sunk in the frond.

Subtribe 2. SPONGIOCARPE^E. Frond so-
lid, dense, cartilaginous or horny. Favellidia
of several, imperfectly known. Wart-like
swellings composed of filaments ; sometimes
containing tetraspores, sometimes spores.

Chondrus. Frond fan-shaped, dicho-
tomously cleft, cartilaginous, of very dense
texture. Tetraspores collected into sori, im-
mersed in the substance of the frond.

Phyllophora. Frond stalked, rigid, mem-
branaceous, proliferous from the disk,
of very dense structure. Tetraspores in dis-
tinct superficial sori, or in special leaflet-
like lobes.

Peyssonelia. Frond depressed, expanded,
rooting by the under surface, concentrically
zoned, membranous or leathery. Tetra-
spores contained in superficial warts.

Gymnogongrus. Frond filiform, dicho-
tomus, horny, of very dense structure.
Tetraspores strung together, contained in
superficial wart-like sori.

Polyides. Hoot scutate. Frond cylin-
drical, dichotomous, cartilaginous. Favellee
contained in spongy external warts. Tetra-
spores scattered through the peripheric stra-
tum of the frond, cruciate.

Furcellaria. Root branching. Frond
cylindrical, dichotomous, cartilaginous. Fa-
vellce unknown. Tetraspores deeply im-
bedded among the filaments of the periphery,
in the swollen pod-like upper branches ox
the frond, transversely zoned.

CRYPTONEMIACE^E. [ 218 ] CRYSTALLOGRAPHY.

Subtribe 3. GASTROCARPE^:. Frond
yelatinously membranaceous or fleshy, often
of lax structure internally. Favellidia im-
mersed in the central substance of the frond,
very numerous.

Dumontia. Frond cylindrical, tubular,
membranaceous. Tufts of spores attached
to the wall of the tube inside.

Halymenia. Frond compressed or flat,
gelatinoso-membranaceous, the membra-
nous surfaces separated by a few slender
anastomosing filaments. Masses of spores
attached to the inner face of the membra-
nous wall.

Ginannia. Frond cylindrical, dicho-
tomous, traversed by a fibrous axis; the
wall membranaceous. Masses of spores
attached to the inner face of the membra-
nous wall.

Kallymenia. Frond expanded, leaf-like,
fleshy-membranous, solid, of dense struc-
ture. Favellidia like pimples, half im-
mersed in the frond, and scattered over its
surface.

Iridcea. Frond expanded, leaf-like, thick,
fleshy-leathery, solid, of dense structure.
Favellidia wholly immersed, densely
crowded.

Catenella. Frond filiform, branched,
constricted at intervals into oblong arti-
culations; the tube filled with lax fila-
ments.

Subtribe 4. GLOIOCLADEEJE. Frond
loosely gelatinous ; the filaments lying apart
from one another, surrounded by a copious
gelatine. Favellidia immersed among the
filaments of the periphery.

Cruoria. Frond crustaceous, skin-like.

Naccaria. Frond filiform, solid, cellular ;
the ramuli only composed of radiating free
filaments.

Oloiosiphonia. Fi'ond tubular, hollow;
walls of the tube composed of radiating
filaments.

Nemaleon. Fronds filiform, solid, elastic,
filamentous ; the axis composed of closely-
packed filaments ; the periphery of monili-
f orm free filaments.

Dudresnaia. Frond filiform, solid, gela-
tinous, filamentous ; the axis composed of
a network of anastomosing filaments ; the
periphery of moniliform free filaments.

Crouania. Frond filiform, consisting of a
jointed filament, whorled at the joints, with
minute, multifid, gelatinous ramuli.

BIBL. Harvey, Marine Algce ; Derbe's et
Solier, Ann. Sc. Nat. 3 s<§r. xiv. 273. See
also the Genera.

CRYPTOSTPHUM, Buckt.— Agenusof
Aphidae.

Char. Cornicles none or mere pores;

cauda small ; antennae with 7th joint short.

C. Artemisice. Brown or blackish, very

mealy ; eyes reddish. On Artemisia vulgaris,

deforming and colouring the leaves.

BIBL. Buckton, Aphides, ii. 145.

CRYPTOSPO'RIUM, Kze.— A genus of
Sphaeronemei (Stylosporous Fungi). Mi-
croscopic Fungi growing upon bark and
leaves, producing spindle-shaped spores, at
first conglutinated beneath the epidermis of
the nurse-plant. Two species have been
recorded as British.

C. Caricis, Corda. Heaps of spores
punctiforin; spores slightly curved, dark
brown and pellucid. On leaves of various
sedges. Corda, apud Sturm, Deutschl. Flor .
t. 1.

C. vulgare, Fries. Heaps confluent;
spores curved, black (subhy aline). On dead
twigs of birch, hazel, alder, &c. Corda, /. c.
t. li.

BIBL. Berkeley and Broome, Ann. N. H.
2 ser. v. 371 ; Fries, Syst. Myc. iii. 481.

CRYPTOSTE'GIA, Reuss.— A group of
hyaline Foraminifera, having an Agathiste-
gian or Milioline mode of growth, compri-
sing Chilostomella and Allomorphina, Reuss,
and probably Ellipsoidina, Brady. These
are near allies of Spharoidina, and there-
by related to Pulknia and Globigerina.
Chilostomella has successive chambers,
almost entirely overlapping one another, as
in Biloculina, but with a hyaline, and not
a porcellaneous shell. Allomorphina is
triloculine.

Recognized in Cretaceous and Tertiary
strata, and in existing oceans.

BIBL. Reuss, Sitzungs. Akad. Wien,
1861, xliv. 372 ; Brady, Qu. Mic. Jn. xix.
66.

CRYSTALLINE LENS. See EYE.

CRYSTALLOGRAPHY.— The laws of
crystallography teach us that in perfectly
formed crystals, each peculiar chemical com-
bination corresponds to a distinct relation
of all the angles which can possibly arise
from the primary form ; hence by ascer-
taining the latter, we can usually infer the
former. It was our intention to have given
a sketch of the method of determining the
primary forms of the more common micro-
scopic crystals, and the systems to which
they belong ; but our space is far too limited
for this purpose, and the subject is so diffi-
cult, that we must rest satisfied with a re-

CRYSTALLOIDS.

[ 219 ]

CTENOSTOMATA.

ference to works specially devoted to the
subject.

BIBL. Schmidt, Enttv. em. allg. Untersuch.
fyc. ; Robin and Verdeil, Chimie Anatom.
$c. ; Phillips, Intr. to Mineral. (Brooke
and Miller) ; Dana, Mineral. ; Naumann,
Elem. d. Min. ; Nicol, Man. of Miner. ;
Rammelsberg, Krystallkunde ; Nageli &
Schwendener, Mikr. 478.

CRYSTALLOIDS.— These bodies have
beennoticed under CHALK and COCCOLITHS.
The term has been more recently ex-
tended to certain bodies formed of the
protoplasmic contents of vegetable cells,
which assume crystalline forms, and exhibit
the facets and polarizing properties of
crystals, yet possess resemblances to organic
cell-structures. They are usually colourless,
sometimes coloured, the colouring matter
being removeable. They swell with re-
agents, and consist of two substances of
different solubility. They are found in the
cell-nuclei of Lathrea, the cells of the skin
of the potato, in seeds, and in aleurone-
grains (page 28, fig. 66).

So that we now have 3 kinds of crys-
talloids : Ehrenberg's chalk- and concre-
tionary crystalloids ; the vegetable crystal-
loids ; and Graham's (dialytic) crystalloids
=true crystalline matter.

BIBL. Hartig, Bot. Zeit. 1856, 262;
Badlkofer, Kryst. prot. 1859 ; Nageli, Bay.
Ak. 1862, 233; Sachs, Bot. 50; Rodwell,
Diet. So. 162.

CRYSTALS.— Crystals are constantly
met with in the examination of animal
and vegetable products ; and the determina-
tion of their nature or composition is often
of great importance.

There are five methods of ascertaining
this : 1, by ascertaining the atomic weight
of the substance, or by its quantitative ana-
lysis ; 2, by the study of its crystallographic
properties ; 3, by its qualitative analysis ;
4, by its spectroscopic analysis; 5, by its
polariscopic analysis.

The first belongs to the domain of che-
mistry, and requires an appreciable quantity
of substance.

The second requires well-formed crystals,
and a knowledge of crystallography. As the
latter is an exceedingly difficult science, re-
course is generally had to the third method
upon which some remarks have already been
made in the INTRODUCTION, p. xlii ; the
fourth is indispensable in many cases, bu1
requires expensive apparatus and great prac-
tice ; the fifth is only partially applicable.

The forms of crystals vary according to
the conditions under which they are pro-
duced ; but there can be no doubt that, under
absolutely the same conditions, their forms
would be relatively constant. In many ani-
mal and other liquids, the forms assumed by
the crystals deposited are tolerably charac-
teristic, so that their composition may be
inferred ; but where accuracy is required, it
is always well to use chemical reagents.
See RAPHIDES.

The cavities in topaz and other mineral
crystals were shown years ago by Brewster
to enclose a liquid, crystals, or even a va-
cuum. This subject has been further in-
vestigated by Sorby and Rutley in rocks,
stones, lava, &c., and important geological
conclusions have been deduced therefrom.
Attention has also been drawn to the cavi-
ties containing air or vapour in artificial
crystals, and to the crystals formed in blow-
pipe beads.

Crystals, when rapidly formed, constitute
beautiful microscopic objects ; the arbores-
cent, radiating and other appearances which
they present are well known ; and a more
exquisitely curious and interesting sight
cannot be witnessed than the very formation
itself taking place under the the microscope.
This may be readily seen in a drop of any
saline solution spontaneously evaporating
upon a slide. See URIC ACID and POLAR-
IZATION; and for crystals in plants, RA-
PHIDES.

BIBL. Sorby, Geol. Jn. xviii. ; id. (blow-
pipe beads) Mn. Mic. Jn. i. 349 ; and Jn.
Mic. Soc. 1878, i. 1; Guy, Mic. Trans.
1868, 1 ; Davies-Matthews, Mounting, 111 ;
also CHEMISTRY, CRYSTALLOGRAPHY, and
ROCKS.

CTENOSTO'MATA.— A suborder of
Infundibulate Polyzoa (Bryozoa). Distin-
guished by the cell-orifice being surrounded
by a fringe of bristles (more or less deve-
loped) when the animal is protruded.
Families :

Alcyonidiidce. Polypary sponge-like,
fleshy, irregular in shape ; cells immersed,
with a contractile orifice.

Vesiculariidce. Polypary plant-like, horny,
tubular ; cells free, deciduous, the ends
flexible and invertible.

PedicellinidcB. Polypary plant-like, creep-
ing, adherent, sending up at irregular
intervals free, erect, stalked bodies, without
distinct cells.

Flustrettidee. Cells immersed in a gela-
tinous crust, orifice bilabiate.

CUCULLANUS.

[ 220 ]

CULICID^E.

ArachniidcB. Cells more or less distant,
membranous.

Buskiida. Cells contracted below, not
continuous with the creeping stolon ; with
a ventral aperture.

Cylindrcecidce. Cells not contracted below,
closely united to the stem ; no membranous
area.

Triticellidce. Cells horny, with an aper-
ture, and a ventral membranous area;
attached to a rigid peduncle by a moveable
joint, deciduous.

Victorettidce. Cells originating in an en-
largement of the creeping tubular stem,
with which they are continuous at the base ;
free and cylindrical above, not deciduous.

BIBL. Johnston, Br, Zooph. ; Gosse,
Mar. Zool ii. ; Hincks, Polyz. 489.

CUCULLA'NUS,MulL— Agenus of En-
tozoa, belonging to the order Ccelelmintha,
and family Nematoidea.

Char. Body elongate, posteriorly attenu-
ate ; head broad, with a bivalve manduca-
tory apparatus ; mouth anterior, terminal,
forming a long vertical fissure.

C. eleyans. In the intestine, stomach,
and pyloric appendages of the perch and
other freshwater fishes. Almost all the
other species of this genus live in the in-
testines of fishes. Length 1-6 to 1-3".
Colour, reddish yellow.

C. foveolatus, in the plaice.

BIBL. Dujardin, Helminthes, 245 ; Cob-
bold, Paras. 474.

CUCURBITA'BIA, Grev. See SPHJE-
BIA.

CU'LEX, Linn. — A genus of Dipterous
Insects, of the family CuLicms:.

Char. Palpi longer than the proboscis in
the male, very short in the female

Many species. C. pipiens, the common
gnat. See CULICIDJB

CULICID^E.— A family of Dipterous
Insects, as the type of which the common
gnat ( Cukx pipiens) may be examined.

The parts of the mouth are produced into
a slender elongated rostrum or proboscis,
which is nearly half the entire length of the
insect, and slightly thickened at the tip.
This proboscis, simple as it appears, in re-
ality consists of seven pieces in the females,
besides a pair of many-jointed palpi, which
are as long as, or even longer than, the
rostrum in some of the mates, and very
hairy at the extremity; in the females, how-
ever, they are generally very short. Head
small. Antennae slender and filiform, as
long as, or longer than the thorax, and 14-

jointed in both sexes, but plumose in the
male (PL 33. fig. 21) and pilose in the
females (PI. 33. fig. 30 a) ; the basal joint
is subglobose and tubercular in form. Eyes
lunate; ocelli obsolete. Thorax oblong-
oval. Abdomen long and slender, upon
which the wings are incumbent when at
rest ; the latter have the veins furnished
with scales (PI. 34. fig. 22). Legs very
long and slender.

The proboscis of the female is composed
of the following parts : — 1. An outer tubular
canal (PI. 33. figs. 30 & 31 e\ representing
the labrum, forming the most robust part of
the mouth, except the labium. 2. A pair of
slender, needle-like pieces, the mandibles,
serrated on the inside near the tip (PL 33.
figs. 30 & 31/), thickened at the back, like
a scythe, and transversely striated. 3. A
second pair of very delicate and slender
organs (PL 33. figs. 30 & 31 g\ dilated at
the base, to which the palpi are attached,
representing the maxillae. 4. A slender,
needle-like instrument, lanceolate at the
end, traversed by a narrow canal (PL 33.
figs. 30 & 31 d), the analogue of the tongue.
5. The outer tubular canal (PL 33. fig. 30 i),
in which the others are lodged when at
rest, and representing the labium. The
labrum and labium are each traversed by a
longitudinal slit throughout their length.

It appears that in the males the labrum
and tongue are absent. It has been sup-
posed that, when the lancets of the female
gnat are introduced into the skin, a veno-
mous liquid is simultaneously instilled into
the wound, and that the great irritation
produced may thus be accounted for. It is
more probable, however, that this arises
from the deeper penetration of the lancets
into the skin ; for they are of great compa-
rative length — about four times that of the
lancets of the flea.

The eggs are deposited in a small boat-
shaped mass which floats upon the surface
of the water. They are oval, with a small
narrow knot at the top, and are arranged
side by side, and closely packed.

The larvae inhabit standing waters, and
may be observed frequently, during the
spring and summer, jerking themselves
about with great agility, or suspending
themselves, for the purpose of respiration,
immediately below the surface of the water
with the head downwards. The head (PL
35. fig. 1) is distinct, large, rounded, and
furnished with two unjointed antennas, and
several ciliated appendages, which serve for

CULTIVATION.

[ 221 ]

CURCUMA.

obtaining nourishment. The thorax is fur-
nished with "bundles of feathery hairs ; the
abdomen is long, nearly cylindrical, much
narrower than the front parts of the body,
and divided into ten segments, the eighth
of which is furnished with a long respiratory
air-tube, terminated by a small star ; the
last joint is terminated by setae, and by five
conical slender plates.

After several moultings, the larvae are
transformed into pupae, which also move
about with agility by means of the tail and
two terminal swimming organs. In this
state they take no food ; and the position in
which they suspend themselves in the water
is the reverse of that previously assumed,
i. e. the head is upwards. The respiratory
organs consist of two air-tubes placed upon
the thorax ; and the body is much curved.
The final transformation takes place in three
or four weeks, the exuviae of the pupa serv-
ing as a raft, upon which the insect remains
until its wings are extended.

BIBL. Westwood, Introd. 507 ; Robineau
Desvoidy, Mem. Soc. cTHist. N. iii. 1827,
390 ; Stephens, Zool. Jn. i. ; Curtis, Brit.
Entom. xii. 537; Macquardt, Dipt. (Suites
it Buff ^ ; Walker, Insect. Brit., Dipt. iii. 242.

CULTIVATION or CULTURE.— This
term has recently been used in a specific
sense, to signify the growth of the Schizo-
mycetes, such as Bacterium, Bacillus, &c.,
in artificial liquids. It has been observed,
that when these organisms reproduce them-
selves in organized bodies, the reproduction
takes place by simple vegetative division.
But when grown in the artificial soils, with
free exposure to air, they produce new forms
and give rise to spores. At the same time,
in the case of those Bacteria &c. which are
the origin of specific diseases, their viru-
lence is found to be destroyed ; and on in-
oculation, instead of the original virulent
disease being produced, a mild form of the
same, which exerts a protective influence,
is the result.

Several cultivation-liquids have been
used, among which the following may be
mentioned. Pasteur's liquid, composed of
phosphate of potash 2 pts., phosphate of
lime 12, sulphate of magnesia '2, tartrate of
ammonia 10, sugar-candy 150, and water
857 pts. ; or tartrate of ammonia 1 pt.,
yeast-ash 1, distilled water 100 pts. Cohn's
liquid consists of 1 pt. phosphate of potash,
1 sulphate of magnesia, 2 tartrate of am-
monia, and '1 of chloride of calcium in 200
pts. of distilled water. These liquids should

be thoroughly sterilized by boiling before
use, and should be kept in stoppered
bottles. More recently, the cut surface of
a potato, or beetroot, has been used as a
cultivation-bed ; also a layer of gelatine so
saturated with water as just to solidify on
cooling. In these experiments, it has been
found that there is no transition of forms,
at least among the pathogenous Schizomy-
cetes ; a micrococcus producing micrococci, a
bacillus bacilli, and a spirillium spirillia
only.

BIBL. See SCHIZOMYCETES ; Maddox,
M. M. Jn. 1870, iii. 14 j Koch, Qu. Mic.
Jn. xvii. 87, and xxi. 650 ; Lister, ibid, xviii.
191 j Klebs, Rep. Intern. Med. Cong.,
Times, Aug. 8, 1881 j Pasteur, ibid. Aug.
9, 1881.

CUNEOLINA, D'Orb.— A Textularian
Foraminifer, extremely compressed trans-
versely to the usual direction of the com-
pression in Textularia.

Rare in the Lower Cretaceous forma-
tion.

BIBL. D'Orbigny, For. Foss. Vien. 1846;
Carpenter, Introd. For. 193.

CUPRESSIN'EvE.— A suborder of Coni-
ferae (Gymnospermous Flowering Plants),
distinguished from the Abietineae by the
erect ovules and spheroidal pollen-grains.
Further particulars will be found under
CONIFER JE and WOOD.

CURCU'LIO, Linn.— A genus of Coleo-
pterous Insects of the family Curculionidaa
(weevils).

Curculio imperialis, the diamond-beetle,
is well known on account of the splendid
colours which its elytra exhibit. Many
other members of this family present co-
lours almost equally brilliant. These colours
are produced mainly by the action of minute
scales upon the incident light. See SCALES
OF INSECTS.

The oral organs of the Curculionidaa are
curiously placed at the end of an elongated
rostrum which represents the head, and
to the sides of which the antennae are at-
tached.

BIBL. Westwood, Introd. ; Stephens,
British Beetles.

CURCU'MA, L.— A genus of Zingibera-
ceae (Monocotyledons), remarkable on ac-
count of the tuberous rhizomes. Those of
C. longa form the substance called turmeric;
and the starch from the cells of the young
tubers forms one of the kinds of East-Indian
arrowroot. The tubers of other species
yield very pure starch, and furnish East-

CUSCUTA.

[ 222 ]

CYATHE.E.

Indian arrowroots. The grains of an un-
known Curcuma imported under that name
are represented in fig. 19 of Plate 46.

CUS'CUTA, Tournefort.— A curious ge-
nus of Convolvulaceae (Dicotyledons), con-
sisting of parasitical, leafless plants, annual
or perennial, nourished by short radical
processes, which they usually send into the
interior of the stems of the plants upon
which they live, although they sometimes
affix themselves to leaves also ( C. Epithy-
mum). C. Epilinum, which grows in cul-
tivated fields of flax, and C. Trifolii, para-
sitical on clover, twine round the stems like
a fine red string, and produce root-pro-
cesses in rows on the side next the nurse-
plant, never 011 the free side. Careful
sections show that the woody structure of
the roots of the parasite penetrates the cam-
bium (or even the pith) of the nurse-plant,
and becomes completely grafted on it. In
the perennial kinds (C. verrucosd), the roots
become imbedded in the annual rings. The
embryo of Cuscuta is curious, being filiform,
and coiled up like a watch-spring in the seed.

BIBL. Wheeler, Phytologist, i. 753;
Brandt, Linncea, xxii. 81 ; Schacht, Beit.
z. An. und Phys. 1854, 167 j Uloth, Flora,
1860, 265.

CUSPIDEL'LA, Hincks.— A genus of
Hydroid Polypi ; family Lafoeidae.

C. humilis. Wales, Shetland, Northum-
berland.

BIBL. Hincks, Brit. Zooph. 209.

CUTICLE OF ANIMALS. See SKIN.

CUTICLE OF PLANTS. See EPIDER-

MIS.
CUTLE'RIA.— A

genus of Cutleriaceae
(Fucoid Algae), re-
presented in Britain
by C. multifida, which
has a " rooting," fan-
shaped, irregularly
laciniated frond from
2 to 8" long, the laci-
nise riband-like, be-
tween cartilaginous
and membranous,
olive, with scattered
sori, bearing on some
plants(which have an
orange tint) antheri-
dia, and on others oo-
sporanges (fig. 148).

The oosporanges
(fig. 148) occur at
the bases of tufted

Fig. 148.

Cutleria dichotoma.

Fragment of a frond.

Nat. size.

hairs, and are oblong stalked bodies, divided
by perpendicular and transverse septa into
(usually) 8 chambers, each of which gives
birth to a zoospore capable of germination.
The antheridia occur in an analogous con-
dition on distinct plants ; they are more
sausage-shaped, and divided into a greater
number of minute chambers, from which
the spermatozoids or antherozoids are ex-
pelled when mature ; these have never been
seen to germinate.

BIBL. Harvey, Mar. Alg. 36, pi. 6. A ;
Phyc. Brit. pi. 75; Greville, Brit. Alg.
pi. 10; Thuret, Ann. Sc. Nat. 3 se"r. xiv.
241, pi. 31, xvi. 12, pi. 1 j Kiitzing, Phyc.
gen.^l. 25. fig. 2.

Fig. 149.

Cutleria dichotoma.

Section of a lacinia of a frond, showing the Btalked
eight-chambered oosporanges growing in tufts with
intercalated hairs. Magnified 50 diameters.

CUTLERIA 'CE^E.— A family of Fucoid
Algae. See CUTLERIA.

CUTTLE-FISH. See SEPIA.

CYATHE'^E.— A family of Polypodia-
ceous Ferns, distinguished by the dorsal
globose sori, often at or near the forking of
a vein, and the insertion of the sporanges
on a projecting axis, the annulus of the
sporanges being vertical (fig. 151) ; indu-
sium (except in Alsophild) enclosing the
sori.

CYATHEA.

[ 223 ]

CYCLAMMINA.

Tropical or subtropical, mostly arbo-
rescent.

Genera.

Cyathea. Sori hemispherical, regularly
arranged. Indusium at first closed, at
length bursting in a circumscissile manner,
and cup-shaped.

Alsophila. Sori globose, regularly ar-
ranged. Sporanges inserted on a globose
axis, and imbricated.

Hem&eUa. Sori globose, each solitary
on a venule. Indusium an ovate, concave,
torn scale, situated at the lower side of the
base.

Cnemidaria.

Dicalpe. Receptacle small, scarcely ele-
vated. Indusium hard-membranaceous, en-
tire, finally bursting irregularly at the
summit ; capsules numerous, nearly sessile,
annulus broad.

Matonia. Receptacle expanded into a firm
and membranaceous umbrella-shaped ob-
scurely 6-lobed indusium, enclosing 6 large
sessile capsules.

Thyrsopteris.

CYATHEA, Smith.— A genus of Cya-
these (Polypodiaceous Ferns), most of which
are tropical. They have a cup-like in-
dusium, whence the name. Arborescent.
(Figs. 150, 151.) 55 species.

Fig. 150.

Fig. 151.

Cyathea elegans.

Fig. 150. Pinnule with sori. Magnified 5 diameters.
Fig. 151. Vertical section of a sorus in a cup-like in-
dusium. Magnified 25 diameters.

BIBL. Hooker and Baker, Syn. Fil. 16.

CYATHO'MONAS, From. = Monas
truncate or excavate in front.

8 species; freshwater; length 1-3000 to
1-1000". C. spissa (PI. 53. fig. 17).

BIBL. Fromentel, Microzoaires ; Kent,
Infm. 141.

C Y ATHUS, Hall.— See NIDULAKIACEI.

CYCADA'CE^E.— A family of Gymno-

spermous Flowering Plants. The micro-
scopic structure of the wood is analogous to
that of the Conifers; and the mode of ferti-
lization of the ovules is similar. (See GYM-
NOSPEBMIA.) Species of Cycas, Zamia, &c.
are commonly cultivated in botanical gar-
dens. They offer interesting subjects of
microscopic investigation. The parenchy-
matous tissue, in the form of pith, large
medullary rays, and in Cycas of concentric
rings alternating with those of the wood, is
remarkable for the quantity of starch con-
tained in it at certain periods. This is ex-
tracted and used as arrowroot or sago. Cycas
circinalis furnishes a kind of sago (its starch-
grains are represented in PI. 46. fig. Vj\
Dion edide yields a kind of arrowroot in
Mexico. Encephalartos yields Caffre-bread
at the Cape, &c. The wood is composed,
in Cycas and Zamia, almost wholly of large
dotted tubes, somewhat like thosevof Araur
caria (with many rows of bordered pits)
(PL 48. fig. 20) ; but a medullary sheath
exists, composed of unreliable spiral vessels,
with tubes of varied character, reticulate,
annular or other fibrous forms, as in the
Dicotyledons; and in Zamia the dotted
tubes are said to be unreliable in some cases
into spiral ribands. In Zamia and Ence-
phalartos there does not appear to be a dis-
tinction of concentric rings of wood; but
in Cycas these exist, separated by layers of
cellular tissue. The rings, however, are
not " annual," only five or six existing in
large old trunks. The leaves of the Cyca-
daceae possess a remarkably solid epidermal
structure ; and in Cycas the upper thickened
walls of the epidermal cells exhibit pore-
canals or deep pits running from the cavity
of the cell towards the outer surface, as well
as towards the contiguous cells (PI. 47.
fig. 28). See EPIDERMIS. The pollen of
the Cycadaceee is angular, collected in
masses, and transparent ; it is contained in
anthers of peculiar form seated on the lower
surface of the scales of the male cones.

BIBL. Don, Ann. N. H. v. 48; Linn.
Trans, xvii. ; Brongniart, Ann. Sc. Nat.
xvi. 589; Mohl, Verm. Schrift. 195; Link,
Icon. Select, f asc. ii. t. ix. & xv. ; Miquel,
Linncea, xviii. 125, and pis. 4, 5, 6 (Ann.
Sc. Nat. 3 sSr. v. 11). Also the BIBL. of
GYMNOSPERMIA.

CY'CAS, L. See CYCADACEJE.

CYCLAM'MINA, Brady.— An arena-
ceous Foraminifer; nautiloid, subglobose.
with numerous chambers, labyrinthic with-
in ; last chamber opening with a transverse

CYCLIDINA.

[ 224 ]

CYCLOPS.

slit and some large pores. Recent ; in deep
parts of the Atlantic and Pacific.

BIBL. H. B. Brady, Qu. Mic. Jn. xix.
p. 43.

CYCLIDI'NA, Ehr.— A family of In-
fusoria.

Char. No carapace ; a single alimentary
orifice ; appendages in the form of cilia or
bristles.

{Flattened, cilia form-
ing a circle Cyclidium.
Hounded, cilia scat-
tered Pantotrichum.

(.bristles Ckattomonas.

BIBL. Ehr. Infus. p. 244.

CYCLID'IUM, Hill, Ehr.— A genus of
Holotrichous Infusoria.

Char. Body compressed ; organs of loco-
motion a circle of abdominal cilia-like feet ;
mouth ventral, with a hood-shaped exten-
sile membrane.

C. glaucoma (PI. 30. fig. 37 c, side view ;
d, dorsal view). Oblong-elliptical, entire,
with a long saltatory seta in front (behind,
Kent); circle of cilia large; dorsal lines
very fine ; contractile vesicle placed at the
front end (back, Kent) ; freshwater ; length
1-2880 to 1-1150". Cl. & L. include under
this species Acomia ovulum, Alyscum saltans,
Enchelys triquetra, and Uronema marina.

C. margaritaceum. Orbicular-elliptic,
slightly emarginate posteriorly ; cilia obso-
lete ; pearly; freshwater; length 1-21 00 to
1-1000" (this is Glaucoma maryaritaceum,
Clap. & Lachm.).

Two doubtful species, — C. planum and
lentiforme.

C. elongatnmj Cl. & L.

Dujardin includes his species of Cycli-
dium, the relation of which to those of
Ehrenberg is doubtful, in the family Mona-
dina, with the characters —

Body disk-shaped, depressed or lamelli-
form, but little variable in form, with a
single nagelliform filament. Four species ;
freshwater.

C. nodulosum. With series of nodules
and vacuoles; motion extremely slow;
length 1-530".

C. abscissum (PI. 30. fig. 37 b). Lamel-
liform, oval, truncated posteriorly ; motion
slow ; length 1-920".

C. distortum (PI. 30. fig. 37 a). Oval,
nodular, irregularly twisted ; margin thick-
ened ; length 1-1800".

C. crassum. Length 1-1800 to 1-1100".

BIBL. Ehr. Infus. 245; Duj. Infus. 286;
01. & L. Inf. 271 ; Kent, Inf. 544.

C YCLOCH/E'TA, Jackson.— A genus of
Peritrichous Infusoria, allied to Trichodina.
C. spongillce. In the interstices of the
freshwater sponge.

BIBL. Jackson, Qu. Mic. Jn. 1875 ; Kent,
Inf. 650.

CYCLOCLY'PEUS, Carpenter.— A re-
latively large, discoidal, Nummuline Fora-
minifer, which grows by concentric annuli
of chamberlets, instead of spirally with suc-
cessive chambers. It thus bears the same
relation to its ally Hcterostegina that Orbi-
tolites does to Orbiculina. Known only re-
cent from Borneo.

BIBL. Carpenter, Phil. Tr. 1856 ; Foram.
292.

C YCLOGLE'NA, Ehr.— A genus of Ro-
tatoria, of the family Hydatinaea.

Char. Eyes more than three, forming a
cervical group ; foot forked.

Pharyngeal jaws with one or perhaps
three teeth.

C. lupus (PI. 43. fig. 18). Body ovate-
oblong or conical, not auricled; foot and
toes short j aquatic ; length 1-144 to 1-120".
C. ? elegans. In Egypt.
BIBL. Ehr. Infus. p. 453.
CYCLOGRAM'MA, Perty.— A genus of
Infusoria.

C. rubens = a Nassula, Cl. & L.
BIBL. Clap. & Lachm. Infus. p. 326 ;
Perty, Leltmf. p. 146.

OYOLOLTNA, p'Orb.— An excessively
thin discoidal condition of Patellina, con-
sisting of perfect annuli and very little um-
bilical cell-growth. In Cretaceous strata,
France.

BIBL. D'Orb. For. Fos. Vien. 139; Par-
ker and Jones, Ann. N. H. ser. 3, vi. 36 j
Carpenter, Introd. For. 230, 233 ; Carter,
An. N. H. 1861, Dec., 464.

CYCLOPI'NA, Claus.— A genus of Co-
pepodous Entomostraca.

C. littoralis, gracilis, and ovalis ; in dredg-
ings.

BIBL. Brady, Copep. i. 91.
CY'CLOPS, Miiller.— A genus of Cope-
podous Entomostraca, family Cyclopidae.

Char. Foot-jaws large and strong,
branched ; eye single, frontal ; inferior an-
tennae simple ; external ovaries two. (Both
superior antennae in the male furnished with
the swelling and hinge-joint.)

C. quadricornis (PI. 20. figs. 8-15). The
only species. Variable in colour; fresh-
water ; length 1-17 to 1-14".

Thorax composed of four, and abdomen
(apparently the tail) of six segments j head

CYCLOPS.

[ 225 ]

CYCLOTELLA.

consolidated with the first and largest joint
of the thorax ; last joint of abdomen con-
sisting of two separate lobes.

Superior antennae (figs. 8, 9 a) composed
of many joints (twenty-six, Baird), from
each of which one or more setae arise ; in
the male, each superior antenna exhibits a
swelling at about its middle (fig. 8 &), fol-
lowed by a sudden contraction, the first
articulation of which forms a hinge-joint ;
inferior antennae (fig. 9 6) four-jointed, each
joint with setae, the terminal with six of
unequal length. The mandibles (fig. 11)
consist of an ovate body (a), narrowed and
twisted above, and terminating in a number
of brownish teeth, with a marginal serrated
seta (b) ; each mandible has also a palpus,
consisting of one segment and two long
filaments.

Behind the mandibles, the first pair of
foot-jaws (fig. 12) are situated ; each con-
sists of a body, convex externally, concave
internally, furnished at the end with two or
three strong teeth, and with a single-jointed
palp-like organ terminated by setae.

The second pair of foot-jaws (fig. 13 a 6)
are divided to the base into two portions ;
an internal (6) smaller, and consisting of
four joints, each with one or more setigerous
spines, the last with three ; and an external
(a) composed of three joints, to the base of
the first of which the internal portion is
attached ; this first joint is the longest, and
furnished on its inner side with two tuber-
cles, each with one or two setigerous spines,
a longer jointed spine arising from near its
distal extremity ; the second joint is fur-
nished with two strong claws of nearly equal
size ; and to its upper edge is attached the
third joint, smaller than the second, also
furnisned with twro claws; some of the
spines are themselves setigerous.

There are five pairs of legs or feet, four of
which are branchial, uniform, and arise from
the thoracic segments. Each of these legs
(fig. 14) is composed of two branches arising
from a common base ; each branch is three-
jointed, and each joint is furnished with
elegantly plumose setae, the last having six
or seven. The fifth pair of legs (fig. 15) are
rudimentary, and arise from the first and
smallest segment of the abdomen ; they are
two-jointed in the female, and three-jointed
in the male.

The external ovary (fig. 9) communi-
cates directly with the internal by means
of a small canal on each side between the
first and second segments of the abdomen.

The tail consists of two lobes, each termi-
nated by four variously setigerous filaments,
the two intermediate being the longest, and
jointed near their origin ; sometimes there
are two joints to each, and the outer ones
are also jointed.

Scarcely a pool of water can be found in
which this animal may not be seen darting
about in various directions. It varies greatly
in structure and appearance, according to
age, locality, sex, &c. ; and these varieties
have been admitted as so many species by
some authors.

PI. 20. fig. 16 represents a recently hatched
Cyclops (Nauplius-form).

The individuals are frequently covered
with Vorticellesand. other parasitic Infusoria.

BIBL. Baird, Ent. 198 ; Koch, Deutschl.
Crustac.; Claus, Wieg. Arch. 1857; Tr.M.
Soc. 1880, 251; Brady, Copep. (Ray Soc.\

CYCLO'SIS. See ROTATION.

CYCLOSTO'MATA.— A suborder of
marine Infundibulate Polyzoa.

Families : Tubuliporidse, Crisiidae, Hor-
neridae, and Lichenoporidae.

CYCLOTEL'LA, Kiitz.— A genus of
Diatomacese.

Char. Frustules free or adherent, disk-
shaped, mostly solitary; valves circular,
flat, convex, depressed or undulated, stria-
ted ; striae radiating.

The frustules of some of the species are
immersed in an amorphous gelatinous sub-
stance.

When the valves of (all?) the species
of Cyclotella are examined under an object-
glass of large aperture, with the central
stop (!NTB. p. xix), the surface is found to
be marked with dots in radiating rows, as
in some species of Coscinodiscus -, hence
these two genera should probably be united.
Some appear to represent the frustules of
Melosira seen in end view.

C. opei'culata, K. (Pyxidicula operculata,
E., Discopka Kutzingii, E.) (PL 16. fig. 21 ;
«, side view ; &, front view). Angles of
frustules in front view rounded ; strife ob-
scure, very short, giving the margin a punc-
tate appearance; freshwater; diameter
attaining 1-1000".

)8. rectangula, K. (C. Kiitzingiana, S.)
(PI. 16. fig. 22). Angles of front view not
rounded ; striae more distinct.

C. Meneghiniana. Valves plane, distinctly
striated at the margin ; fr. wat. ; length
1-1440".

/3. major. Twice as broad.

C. antiqua.) S. (Discopka atmosphenca,

Q

CYCLOTRICHA.

[ 226 ]

CYLINDROTHECA.

E.). Valves convex ; striae broad, reaching
neither the centre nor the margin ; fr. wat. ; j
diam. 1-760".

Kiitzing characterizes three marine spe-
cies, with the valves free from striae, and
seventeen doubtful specie?, marine and fos-
sil, belonging to the genera Actinocyclus,
Discoplea, and Hyalodiscm of Ehrenberg.
Rabenhorst describes 9 species.

BIBL. Kiitzing, Syn. Diat. BacilL 50, and
Sp. Alg. 18; Ehrenberg, Berl. Ber., In/us.,
and Mflerog.; Smith, Brit. Diat. 27;
Thwaites, Ann. N. H. 1848, i. 169.

CYCLOT'RICHA, Kent.— A genus of
Holotrichous Infusoria.

C.citrea—Ophryoglena ritreum, 01. &
Lachm.

CY'CLOUM, Hass.— A genus of Infun-
dibulate Ctenostomatous Polyzoa.

Char. Zoary fleshy, incrusting, covered
with imperforate papillae ; ova in clusters.

C. papillosum. Tentacles 18 ; on Fucus
serratus : referred to Alcyonidium.

BIBL. Hassall, Ann. N. H. 1841, vii.
p. 483; Gosse, Mar. Zool. ii. 19 (fig.);
Hincks, Polijz. 493.

CYLINDROCYS'TIS. See Cocco-

CHLORIS.

CYLINDRCE'CID^E. — A family of
Ctenostomatous Polyzoa.

Gen. : Cylindrcecium and AnguineUa.

CYLINDRCE'CIUM, Hincks.— A genus
of Cylindrcecidae, Ctenostomatous Polyzoa.

Char. Cells elongate, cylindrical, arising
from a creeping stolon; no gizzard. 3
species, marine, on rocks, sea-weeds, &c.

BIBL. Hincks, Poliiz. 535.

CYLINDROLEBE'RIS, Brady.— A ge-
nus of Ostracode Entomostraca, fam. Cypri-
dinidae.

2 recent British species : C. tnaria and
C. tereS) both marine.

BIBL. Brady, Linn. Trans, xxvi. p. 464.

C YLINDROPS YL'LUS, Brady.— A ge-
nus of Cppepodotis Entomostraca. C. Icevis,
in dredgings.

BIBL. Bradv, Copep. (Ray Soc.), iii. 30.

CYLINDRbSPER'MUM,Kiitzing(^a-
baina, Bory and others). — A genus of
Nostochaceae (Conferyoid Algae), with the
filaments less radiating than in the allied
Sphcerozyga ; distinguished under the mi-
croscope by the resemblance of the filaments
to an annulose animal ; the ordinary cells
looking like a long jointed body, the large
elliptic sporangial cell like a thorax, and the
terminal vesicular cell often bearing fine
hairs, like a head. British species :

C. catenatum, Ralfs (PL 8. fig. 4). Fila-
ments monilif orm ; ordinary cells orbicular ;
vesicular cells oval ; sporanges oval, cate-
nate. (Ralfs, Ann. N. H. 1850, vol. v. pi. 9.
fig. 14.) Forming a bluish stratum, con-
taining very delicate, elongated, straight or
slightly flexuose, generally parallel filaments.

The remaining British species are not de-
scribed by Ralfs ; but the following are
noticed as British by Kiitzing.

C. macrospermum, Kiitz. Filaments
thick, equal ; ordinary cells oblong, l-700th
of a line in diameter; sporanges oblong,
turgid, firm, fuscous, 1-100 to 1-60'" long,
1-300 to 1-200'" thick. Kiitzing, Sp. Alg.
293 ; Tab. Phyc. vol. i. pi. 98. fig. 4. Ana-
baina impalpebralis, Hassall, Alga, pi. 76.
fig. 3. Standing water; forming an aeru-
ginous green stratum.

C. mesoleptum, Kiitzing. Filaments
densely entangled, unequal, 1-800 to 1-850'"
thick; sporanges oblong, 1-180 to 1-150'"
long, 1-350 to 1-300'" broad, slightly con-
stricted in the middle. Kiitzing, Sp. Alg. ;
Tab. Phyc. vol. i. pi. 98. fig. 5. Anabaina
constricta, Hassall, Algce^ pi. 75. fig. 9.
^Eruginous green ; in brackish marshes.

Excluded species of Kiitzing : — C. elon-
gatum = Sphcerozyga elastica, Ag. (Ralfs) ;
C. kptospermum = Sphcerozyga leptosperma
(Ralfs) ; C. Carmichaelii=-Sph(erozyga Car-
michaelii (Harvey) ; C. Ralfsn=l)olicho-
spermum Ralfsii (Ralfs) ; C. HassaUii= Co-
niophytum Thompsoni (Hassall).

Rabenhorst describes 13 European species.

BIBL. Ralfs on Nostochineee, Ann. N. If.
1850, vol. v. 321 ; Kiitzing, Sp. Alg. ; Ra-
benhorst, Fl. Alg. ii. 186.

CYLINDROS'PORUM, Grev.— A sup-
posed genus of parasitic Fungi, stated by
Tulasne to consist of the conidiiferous forms
of Sphaeriacei.

C. concentricum, Grev. = Uredo cylindro-
spora, Hook. Br. Fl., grows upon the leaves
of cabbages. It appears however, that
Greville's plant is really a species of Glcco-
sporium, and quite different from the fungi
with which it has been confounded.

BIBL. Grev. Sc. Crypt. Fl.t.xxix.; Berke-
ley, Hort. Tr. iii. 265 ; Tulasne, Ann. Sc.
Nat. 4 ser. v. 109 ; Berkeley, Outl 325.

CYLINDROTHE'CA, Rab.— A genus
of Diatomaceae.

Char. Frustules fusiform, free, ends acute ;
with 2 (rarely 1 or 3) longitudinal flexuous
costee ; no nodules.

C. Gerstenbergeri (PI. 51. fig. 34). Living
frustules cylindrical, obtusely attenuate at

CYLINDROTHECIUM. [ 227 ]

CYNIPID.E.

ends ; dried frustules fusiform, acuminate ;
length 1-90". Common in pools and ditches
(Germany).

BIBL. Rabenhorst, Flor. Alg. i. p. 145.

CYLINDROTHE'CIUM, Br. and Sch.

BIBL. Wilson, Bryol. Brit. p. 326.

C YMATONE'MA, Kutz. = undulate-
constricted CEdogonia. (Rabenhorst, Fl.
Alg. iii. 351.)

CYMATOPLEU'RA, Sm.— A genus of
Diatomaceae. This genus was founded by
Hassall as Sphinctocystis, and should be re-
tained (see the laws of nomenclature, in the
Ann. N. H. 1843, ii. 259); but Smith's
excellent Monograph has caused his term to
be generally adopted.

Char. Frustules free, single ; in front
view linear, with undulate margins ; valves
oblong or elliptical, sometimes constricted
in the middle. Freshwater.

Valves with coarse, transverse or nearly
so, rounded elevations appearing as dark
bands ; an interrupted median line ; coarse
marginal dots, and transverse striae ; but
neither alae nor nodules.

Several British species.

8. solea (PI. 16. tig. 23). Valves linear-
elliptic, narrowed on each side towards the
middle ; transverse striae evident ; extreme
length 1-216". Undulations six ; common.

]3. Much shorter ; undulations fewer,
ends apiculate.

S. elliptica (PI. 16. tig. 24). Valves
broadly elliptic, or elliptic-oblong; striae
obscure ; undulations four or five ; length
1-280" ; common.

S. hibernica. Valves broadly elliptic,
acuminate; undulations three; length 1-
25'0'.

BIBL. Hassall, Alga, 436; Smith, Br.
Diat. i. 36 ; Rabenhorst, Fl. Alg. i. 60.

CYMATOSIRA, Grim.— A genus of
Diatomaceae.

Char. Frustules united into bands; un-
dulate in front view ; valves lanceolate,
distinctly punctate ; no median line.

C. Lorenziana (PI. 51. fig. 35). Valves
broadly lanceolate, very convex ; ends pro-
duced. At the bottom of the Adriatic.

BIBL. Rabenhorst, Flor. Alg. i. p. 124.

CYMBALO TOR A, Hagenow.— One of
the Foraminifera Globigerinida, in which
the spiral is merged in a cyclical growth at
an early stage, the shell increasing by rings
of sac-like chambers, which open into the
hollow base of the trochoid shell. C. Poeyi
(D'Orb.) (PL 24. f. 17) is the type.

Cymbalopora is rare in the Upper Chalk,
and some Tertiary strata ; more common in
the tropical seas.

BIBL. Carpenter, For am. 215.

CYMBEL'LA, Ag.— A genus of Diato-
maceae.

Char. Frustules solitary, free ; valves
cymbiform, unsymmetrical, with a subcen-
tral and two terminal nodules, a submedian
longitudinal line, and transverse or slightly
radiating striae. Freshwater and fossil.

Frustules sometimes immersed in an
amorphous gelatinous mass.

C.Ehrenbergii{ K. (PI. 51. fig. 2: a, front
view ; 6, side view). Broadly lanceolate,
apices slightly produced, somewhat obtuse ;
stria3 distinct (resolvable into dots) ; length
1-200". (Fossil in San Fiore deposit.)

Several British species, and more fo-
reign, differing from each other by slight
characters.

Rabenhorst describes 31 European spe-
cies, with numerous varieties.

BIBL. Smith, Brit. Diat. 17; Kiitzing,
Bacill. 79, and Sp. Alg. 57.

CYMBOSIRA, Kutz.— A genus of Dia-
tomaceae.

Char. Frustules resembling those ofAch-
nanthes ; solitary or binate, stipitate, attached
end to end, and thus concatenate. Marine.

C. Agardhii (PL 19. fig. 18). Frustules
linear, slightly arcuate, finely striated,
rounded at ends ; valves oblong- linear,
slightly dilated in the middle, apices ob-
tusely rounded. Length 1-960 to 1-280".

C. minutula, Grun.

BIBL. Kiitzing, Bacill. 77, and S%). Alg.
57 ; Grunow, Wien. Verh. 1863.

CYNIP'ID^E, GALL-FLIES.— A family
of Insects, belonging to the Entomophagous
section of the order Hymenoptera.

Char. Head small, transverse; antennae
inserted in the middle of the face, of mo-
derate length, slender, not geniculated,
composed of twelve to fifteen j oints ; maxil-
lary palpi of four or five, labial of two or
three joints ; thorax oval, gibbous, with the
mesothorax large, and the scutellum very
prominent ; wings transparent, with few
veins, — the anterior usually with three or
four cells, and the posterior with a single
vein ; abdomen short, much compressed,
with a short peduncle, its basal segment very
large, the rest small, forming narrow rings.

In the females of these insects, which are
all of small and some of minute size, the
last segment of the abdomen, which occupies
a considerable portion of its lower surface,

CYNIPID^E.

[ 228 ]

CYNIPID^E.

forms a channel, in which is lodged the very
delicate ovipositor. This organ, the con-
struction of which has been the subject of
some controversy, consists, as pointed out
by Westwood, of the same parts as that
of the ordinary parasitic Hymenoptera
(Ichneumonidce, Chalcididte, &c. ), namely, of
a superior bristle, channelled beneath, and
of two finer inferior bristles, which are re-
ceived into the channel of the former.
Although this ovipositor is not exserted, it
is of great length, reaching up to the base
of the abdomen in a subspiral curve ; it is
enclosed at its base between two broad
plates, representing the basal joints of the
bivalvular sheath of the ovipositor in other
Hymenoptera ; and the slender second j oints
of these valves accompany it to the apex of
the abdomen. All these parts are concealed
within the walls of the abdomen (PI. 36.
tig. 15).

Although placed from their organization
in the same section of the Hymenoptera
as the parasitic Ichneumonidae, most of
the Cynipidae feed upon vegetable sub-
stances in the larva-state. The females
bore with their ovipositor into the tissues of
plants and trees, and there deposit their
eggs, from which small footless larvae are
produced. The irritation caused by the
injury thus done to the tissues, gives rise
to a morbid action in the part of the plant j
attacked, which is thus incited to grow !
out into an excrescence varying in size,
form, and structure according to the specific
nature of the plant, the part of the plant
upon which, and the parasite by which,
the wound has been inflicted. Thus the
oak, which, of all our native trees, is most
infested by Cynipidae, furnishes nourish-
ment to upwards of a dozen species, which
attack all parts of it, from the leaves and
flower-buds to the root, and each of which
confines its operations to a particular por-
tion of the tree, and gives rise to a pecu-
liar excrescence. These morbid growths
are commonly known as galk, and the
insects producing them as Gall-flies; the
family, also, is called GallicolcB by some
authors. The larvae feed in the interior of
the galls ; those of some species are solitary,
whilst of others numerous individuals may
be found in the same gall, according as the
parent insect has deposited one or more
eggs in the same spot. When full-grown,
the larvae usually undergo their transforma-
tions within^the gall ; but in some instances
they eat their way out, bury themselves in

the ground, and there pass to the pupa-state.
The larvae are liable to be attacked by
species of parasitic Hymenoptera, especially
the long-tailed Chalcididse (such as Calli-
mome, PI. 36. fig. 14) ; these pierce through
the substance of the gall and deposit their
eggs in or upon the Cynipidous larvae,
which are subsequently devoured by those
hatched from the eggs of the parasite.

The recent elaborate researches of Adler
show that the Cynipidae exhibit the phe-
nomena of parthenogenesis, and that they
are dimorphic. Thus, in some broods,
both sexes are present ; while in others, fe-
males only are produced. The members of
the two broods are quite dissimilar, and
have been regarded as constituting diffe-
rent genera ; the galls they produce are also
different. These observations serve to solve
the mystery existing some years ago as to
the non- occurrence of males among large
broods of Cynips. He also states that the
reproductive organs in the two kinds of
broods are very similar ; and that there is a
rudimentary receptaculum seminis in the
agamic generations.

The tissues of the galls are sometimes
soft and juicy, sometimes hard and woody ;
in the latter case the woody tissue lies im-
mediately beneath the skin, and within it
is a layer of cellular tissue filled with
starch-grains. These galls are usually
formed on branches or twigs. One of the
most remarkable of them is the Bedeguar
gall of the wild rose, which is produced by
the puncture of Rhodites Rosa (PI. 36. fig.
16) : it is a large gall entirely covered with
compound bristles, like those of the moss-
rose, which give it the appearance of a
ball of moss ; in its interior are numerous
cells, each of which serves as a habitation
for a larva ; and the whole is produced at
the extremity of a shoot of the wild rose,
upon which the female gall-fly deposits
numerous eggs.

The Cherry-gall of the oak-leaf is pro-
duced by Cynips folii (fig. 17), one of the
commonest of our native species ; and an-
other gall-fly, Teras terminalis (fig. 18), by
attacking the young shoots of the oak, gives
origin to the well-known oak-apples. The
leaves of the oak are also attacked by at
least two so-called species of the genus
Neuroterw, which really consists of the
parthenogenetic brood of Spathegaster, the
punctures of which give rise to small, flat,
rounded galls, attached to the leaf only by a
small portion of their lower surface, and

CYNIPIIXE.

[ 229 ]

CYPHELLA,

bearing so close a resemblance to certain
Fungi, that they were at one time supposed
to be parasitic vegetable growths. These
galls, which are commonly known as oak-
spangles, may be met with in abundance
during the winter on the fallen leaves in oak
woods : the flies are produced in the spring ;
and the^ most abundant species in this
country is the Neuroteris longipennis (fig.
19). The root of the oak is attacked by
several kinds, one of which, Biorhiza aptera,
the parthenogenetic form of Teras termi-
nalis, is destitute of wings; another de-
posits its eggs in the male catkins of the
same tree, producing a series of galls re-
sembling a small bunch of currants.

It would be impossible for us here to
enumerate the different kinds of galls pro-
duced by these beautiful little insects even
upon our indigenous plants and trees, the
history of which in many cases is very im-
perfect, whilst we have scarcely any in-
formation with regard to exotic species.
The most important of all is the common
gall-nut, which is produced by the puncture
of the Cynips tinctoria upon the shoots of
the Quercus infectoriay a species of oak
growing in the Levant. The celebrated
Dead-sea apples are also found upon this
oak j they are as large as a good-sized apple,
and of a spongy texture internally, con-
taining only a single larva of a species which
has been described by Westwood under
the name of Cynips insana.

All the species of Cynipidae do not, how-
ever, produce galls. The species of Hartig's
genus Synergus deposit their eggs in other
galls, upon the substance of which the
larvae, when hatched, feed parasitically, and
finally devour the original tenant. Besides
these species, which live partly upon vege-
table and partly upon animal food, there are
many others, forming several genera in
Hartig's classification, which live entirely
as parasites upon other insects, especially
Aphides and the larvae of Dipterous flies ;
thus justifying the otherwise anomalous
position of the Cynipidae, as a phytophagous
family in the Entomophagous group of the
Hymenoptera. Amongst these we need
only mention the species of the genus Allo-
tria, Westw. (Xystus, Hartig), of which a
very abundant one is parasitic upon the rose-
Aphis, and those of the genera Anacharis,
Figites, and Ibalia. The latter, of which one
species only is known in this country, is
remarkable from the structure of its abdo-
men, which is knife-shaped, and has the

segments nearly equal in length; Ibalia
cultellata (PI. 36. fig. 20) is one of the largest
British Cynipidae.

Adler's admirable memoir, in which
many of the galls are figured, will allow of
the identification of most, if not all the
British kinds.

BIBL. Reaumur, Memoires-, Burgsdorf,
Schriften Gesellsch. naturforsch. Freunde,
iv. ; Boyer de Fonscolombe, Ann. Sc. Nat.
xxvi. ; Westwood, Introd. vol. ii., Mag.
Nat. Hist. vi. and viii., and in Guerin's Mag.
Zoologie ; Walker, Ent. Mag. ii. & iii. ;
Brandt and Ratzeburg, Medizin. Zool. ii. ;
Ratzeburg, Forst-Insecten ; Bouche", Natur-
gesch. d. Insecten ; Hartig in Germar's Ze.its.
fur die Entomol. ; Adler, Zeitschr. wiss.
Zool. liii. 151 ; Abridg. McLachlan, Entom.
Mn. Mag. 1881, xvii. 258; Jn. Mic. Soc. i.
443 ; Ormerod, Man. Inj. Ins., 1881.

OYNODON'TIUM, Br. and Sch.=Di-

CBANTJM.

BIBL. Wilson, Bi-yol. Brit. 60.

CYNOPHAL'LUS.— A genus of Phal-
loidei (Gasteromycetous Fungi), distin-
guished from Phallus by having the pileus
imperforate.

C. caninm occurs amongst decayed leaves
in woods.

BIBL. Sow. t. 330 ; Berk. Outl. p. 298.

CYNTHIA, Sav.— A genus of Tunicate
Mollusca, of the family ASCIDIADJE.

The numerous species are from |-2" in
length.

BIBL. That of the familv.

CYPHEL'LA, Fries.— A genus of Hy-
menomycetes (Basidiomycetous Fungi),

Fig. 152.

Fig. 153.

Cyphella Taxi.

Fig. 152. Entire plant, magnified 10 diameters.
Fig. 153. Horizontal section of the wall of the cup ,
showing the basidiospores, magnified 250 diameters.

forming somewhat membranous minute
cups, sessile or stalked upon branches of
trees or upon mosses; bearing basidio-
spores on a layer forming a kind of lining
to the cup; the spores ultimately sepa-
rating as a powder in the interior.

Some supposed species of Peziza, as P.
villosa and P. albo-violascens, appear to be
species of Cyphetta, or rather sporiferous
states of Peziza,

CYPHIDIUM.

[ 230 ]

CYPKIS.

. Fries, Syst. Myc. ii. 201 ; Le*veill<§?
i. Nat. 2 se*r. xvi. 237.

BlBL.

Ann. Sc.

CYPHIDIUM, Ehr.— A genus of Infu-
soria, of the family Arcellina.

Char. Carapace urceolate, tuberculated ;
expansion variable, broad, single and entire.

The carapace is combustible, and re-
sembles a small cube, with a short pedicle.

G. aureolum (PI. 30. fig. 38). Cubical,
gibbous, expansion (fig. 386) hyaline ; fr.
wat. : length 1-570

W
tol-

432'
BIBL. Ehr. Infm. 135.

CYPHODE'RIA, Schlumb.— A genus of
Rhizopoda, of the family Arcellina.

Char. Carapace membranous, resisting,
ovoid, elongated in front, recurved and con-
stricted in the form of a neck and marked
with oblique rows of projections ; orifice
circular, oblique ; expansions very long,
filiform, very slender at the end, simple or
branched.

Agrees with Difflugia enchelys, E. (Tri-
nema, Duj.), in the oblique orifice, the
oblique rows of markings, and the nature
of the expansions, but differs from it in
the presence of the anterior neck-like con-
striction.

Probably species of Euglypha (01. & L.).

C. margantacea. Carapace yellowish, ex-
pansions twice its length ; fr. wat. ; length
1-380 to 1-1 80".

BIBL. Schlumberger, Ann. des Sc. Nat.
1845, iii. p. 255.

CYPHONAU'TES, Ehr.— A genus of
Rotatoria, of the family Megalotrochaea.

Char. Eyes absent ; no teeth.

C. compressw (PI. 43. fig. 19, side view ;
fig. 20, view from above). Compressed,
obtusely triangular, truncate in front, sub-
acutely gibbous at the back j marine ; length
1-180".

BIBL. Ehrenb. In/us. 395.

CYPREL'LA, De Koninck.— A fossil
Ostracod, related to ' Cypridina ; carapace
annulated by superficial transverse furrows.
Found in the Carboniferous Limestone of
Belgium and the British Islands.

BIBL. De Koninck, Garb. Foss. Belg.
1844, 589 ; Jones, M. Mic. Jn. 1870, pi. 61.

CYPRIDEL'LA, De Kon.— A fossil Os-
tracod closely allied to Cypridina. Very
common in the Carboniferous Limestone ot
the British Isles and Belgium.

BIBL. De Koninck, Garb. Foss. Belg.
1844, 590 ; Jones, M. Mic. Jn. 1870, pi. 61.

' CYPRIDI'NA, M.-Edwards.— A genus

of Ostracode Entoniostraca, fam. Cypri-
dinidae.

Char. Valves oval or oblong, smooth,
notched antero-inferiorly, posterior end
somewhat produced. Superior antennae
seven-jointed; setae of moderate length;
natatory branch of inferior antennae nine-
jointed, bearing moderately long setae ; se-
condary branch very small, subulate. Basal
joint of mandibular feet bearing an entire
subconical and densely hairy process ; pe-
nultimate joint much elongated, and beset
on the internal margin with numerous
ringed setae ; last joint very short and al-
most obsolete.

2 European species : C. Norvegica and C.
Messinensis.

Many fossil forms, apparently identical
with Cypridina^ occur in the Mountain-
limestone and the Coal-measures of Europe
and the British Isles ; some also in the
Maastricht Chalk.

BIBL. Brady, Zool. Proc. 1871, 289;
M.-Edwards, Hist. Nat. Crust, iii. 409;
Jones, K.. & B., Mongr. Carb. Entom.,
Pal. Soc. 1871.

CYPRID'IUM.— A genus of Hypotri-
chous Infusoria (Kent, Inf., 215).

CYPRIDOP'SIS,Br.— A genus of Ostra-
code Entomostraca, family Cy prides.

Char. Those of Cypris, except that the
post-abdominal rami are rudimentary and
setiform.

5 living British species. C. vidua, Br. =
Cypris vidua, Bd. ; C. villosa, Br.=C^m
Westwoodii, Bd.

BIBL. Brady, Linn. Tr. xxvi. 375 ; Ann.
Nat. Hist. 1872, ix. 64.

CY'PRIS, Miiller.— A genus of Ostra-
code Entomostraca, family Cypridae.

Char. Lower antennae simple, with a
brush of setae and clawed at the apex; setae
of upper antennae very long ; feet two pairs,
the last bent up between the valves. Post-
abdominal rami forming two elongate rami,
clawed at the apex. Animal swimming
freely.

Body enclosed within a bivalve, horny,
mostly subreniform or long oval carapace
or shell. Superior antennae (PI. 20. fig. 18)
seven-jointed, with pretty long, mostly
feathery filaments, arising from the three or
four last joints. Inferior antennae (fig. 19)
leg-like, five-jointed, giving off the tuft of
usually feathery filaments, the last joint
terminated by four strong curved claws.
Labrum composed of a somewhat hood-
shaped piece, projecting between the two

CYRTOSTOMUM.

[ 231 ]

CYSTOPHRYS.

inferior antennae ; labium or lower lip elon-
gated and triangular. Mandibles (fig. 20)
large, pointed at one end, with five teeth
at the other, and furnished with a three-
jointed setigerous palp, the basal joint of
which has a small branchial joint with five
terminal digitations. First pair of jaws
(fig. 21) consisting of a large basal plate («),
with four finger-like processes at its ante-
rior extremity, one of which is two-jointed,
and all terminated by several long fila-
ments : from the outer edge of this plate
arises a large elongated branchial lamina
(6) giving off from its crescentic margin
nineteen long pectinate spines. Second
pair of jaws (fig. 22) small, and composed
of two flattened joints, the terminal one
having several rigid hairs at the end, and a
lateral palp-like process. First pair of feet
(fig. 23) slender and five-jointed, the last
joint with a strong hook. Second pair of
feet (fig. 24) four-jointed, the last joint
terminated by two short hooks and a spur-
like posterior filament.

Twenty-seven living British species.

C. wrens (tristriata, Bd.) (PI. 20. fiors.
17-25). Shell oval, and somewhat reni-
form, posteriorly exhibiting three narrow
oblique streaks or dark bands ; valves con-
vex, green, and covered with dense short
hairs. Near the centre of each valve are
about seven small lucid spots. Fr. wat.
very common.

Several fossil Ostracoda are referred to
Cypris by palaeontologists.

BIBL. Baird, Entom. 151 ; Straus, Mem.
d. Mus. d. Hist. Nat. vii. 1821 ; Edwards,
Hist. N. Cntst. iii.; Brady, Linn. Tr.
xxvi. 360, and Ann. N. H. 1872, ix. 64 ;
Hup. Jones, Mon. Tert. Entom., Palceont.
Soc. 1836; Geol. Mag. vii. 158.

CYRTOS'TOMUM, Stein.— A genus of
Holotrichous Infusoria.

C. leucas=Bursaria (Frontonia) I.

CYSTIC OXIDE or OYSTINE.— A
very rare component or constituent of uri-
nary calculi in man and the dog. It is
stated also to occur in the urine, in solution
and as a crystalline deposit ; but we have
never met with it.

Cystine is insoluble in water and alcohol ;
soluble in mineral acids, but not in acetic
acid; also soluble in solutions of fixed
alkalies, their carbonates, and in solution of
ammonia. It is precipitated from its solu-
tion by acetic acid.

Its crystals form colourless, regular six-
sided plates or prisms (PL 13. group 5) ; the

larger crystals usually exhibit a number of
smaller hexagonal tables irregularly arranged
upon them; sometimes rectangular plates
are met with. The crystals usually exhibit
but little colour with polarized light. Cys-
tine is most readily obtained in crystals
from a calculus by solution in ammonia and
spontaneous evaporation.

Some of the forms of lithic acid prepared
artificially, resemble those of Cystine (P1.12.
group 8 b] ; they may be distinguished by
the addition of ammonia, which dissolves
the cystine, but has little or no action upon
the uric acid.

Carbonate of potash also somewhat re-
sembles cystine in the form of its crystals
(PI. 10. fig. 13) j but water or acetic acid
will at once distinguish them.
f CYSTICER'CUS,Rud.— Formerly con-
sidered a genus of Cystic Entozoa; but
now known to be the scolices of Tcenia.
They consist of the short body of a Tcenia,
with the double crown of hooks and the
suckers, terminated posteriorly by a larger
or smaller cyst or vesicle. They occur in
the organs and the tissues of animals ; when
reaching the alimentary canal, becoming
developed into the perfect Teenies. They
have no sexual organs.

C. cellulose (PL 21. fig. 3), the most
common, is the scolex of Tcenia solium.
The head is almost tetragonal, neck very
short ; body cylindrical, often longer than
the vesicle ; breadth of cyst half an inch ;
length of body, 1-6 to 2-5", or I" when ex-
tended. Occurs in the anterior chamber
and beneath the conjunctiva of the eye,
also in the voluntary muscles and brain of
man ; in the connective tissue of the pig,
producing " measly pork ;" also in the ape,
the dog, the ox, &c. C. tenuicollis of the
sheep is the scolex of T. marginata of the
dog; C. fasciolaris, of the rat and mouse
(PL 21. fig. 3 b, head) = T. crassicollis of the
cat; C. pisiformisofthe rabbit =T. serrata
of the dog ; C. talpce and C. longicollis, in-
festing moles, become respectively T. tenui-
collis and T. crassiceps of the fox.

BIBL. Dujardin, Helm. 632; Monier,
Cysticerq. 1880 ; Beneden, Vers Cestoiden j
Cobbold, Parasites, and the Bibl. of TJENIA.

CYS'TINE. See CYSTIC OXIDE.

CYSTOCOC'CUS, Nag. = PBOTOCOC-
cus.

CYS'TOPHRYS, Archer.— A genus of
Rhizopoda

2 species : C. Hackeliana and C. oculea,

BIBL. Archer, Qu. Mic. Jn. 1869, 259.

CYSTOPTERIS.

[ 232 ]

CYSTOSEtRA.

CYSTOP'TERIS, Bernhardi.— A genus
of Davalliese (Polypodiaceous Ferns), con-
Fig. 154.

Cystopteris fragilis.

A pinnule with the sori covered by the indusia.

Magnified 10 diameters.

taining several elegant little indigenous
species (fig. 154).

BIBL. Hooker and Baker, Syn.Jil. 103.

CYS'TOPUS,Le'veille'.— A genus of Ure-
dinei (Phy corny cetous Fungi), of which the
4 white rust ' common on cabbages and other
Cruciferous plants is a good example ; ap-
pearing in white pustules, eventually burst-
ing and destroying the epidermis of the
leaves, stalks, flowers, and seed-vessels of
the infected plants. When fine slices of
these pustules are examined under the mi-
croscope, the mycelium is found, creeping
among the cells of the parenchyma, com-
posed of inarticulate, tubular, branched
filaments, with a colourless membrane and
whitish granular contents. Numerous rami-
fications spread out in the plane of the
epidermis ; while others spring up in tufts
of two to seven, or rarely singly, perpendi-
cular to the former, to produce spores.
These erect branches are at first merer,
pouches projecting from the horizontal fila-
ments; they gradually swell into ovate-
cylindrical or club-shaped sacs. The con-
tents in the summit of each such sac be-
come organized into a spore, which at length
quite fills up the top of the sac (sporange).
Then the sac or sporange becomes con-
stricted under this first spore, and the for-
mation of a second commences under the
constriction. This is repeated until a neck-
lace-like chain of spores is produced, the
spores subsequently becoming somewhat
cylindrical or cubical. The number appears
indefinite ; five and seven spores have Deen
found in a chain ; they are united by the
constricted portions of the sporange ; and

even when they have fallen apart, these
connecting pieces are seen projecting on
them like parts of a stalk from which they
have been broken off. Both the adherent
sporangial membrane and the smooth proper
coat of the spores are colourless, the con-
tents granular and whitish. Tulasne has
recently discovered another form of spore,
spheroidal or trigonal, and of a yellow co-
lour, only one or two of which are formed
from the end of a fertile filament. Oospores
are also found deeply seated amongst the
mycelium ; and zoospores (PI. 27. fig. 14)
have been found by De Bary in C. can-
didus. See UBEDINEI. British species;
formerly placed in the Uredinei, but more
nearly allied to Peronosporce : —

C. candidus. LeV. Very common on
Cruciferae, producing great distortion in the
growth. (Jredo Candida, Pers., Grev. Sc.
Crypt. Fl. t. 251.

C. cubicus, Str. On goatsbeard. Cooke,
Exs. no. 88.

C.Sepigoni,T)Q By. On Spergularia rubra.
Cooke, Exs. no. 88.

C.spinulosus, De By. On Cirsium arvense.
Cooke, Exs. no. 89.

BIBL. Le'veille', Ann. Sc. Nat. 3 s^r.
viii. 369 ; Berkeley, Hart. Trans, iii. 265
(figs.); De Bary, Brandpilze,^ei\m, 1853,
p. 20, pi. 2. figs. 3-7, and Ann. Sc. Nat.
1803, xx. 130 (zoospores) ; Tulasne, Ann.
Sc. Nat. 4 s$r. ii. 108, 171 ; Sachs, Bot.
279.

C YSTOSEI'RA, Ag.— A genus of Fuca-
ceee(Fucoid Algae), of much-branched habit,
some species of which are common on rocks
in tide-pools or between tide-marks. The
gradually attenuated branches contain in-
flated air-sacs, at intervalsalong their length,
within their substance. The conceptacles
are immersed in the ends of the branches,
which are pierced by their numerous pores.
They contain both spores and antheridia,
but not mixed ; the spores occur at the bot-
tom of the cavity, the antheridia above, near
the pore. The antheridia have only a single
coat. The antherozoids are expelled in a
mass, and soon after begin to move, turning
rapidly unon their axes. They are oval or
spnerical in one direction, and rather com-
pressed in the other. They have two cilia
inserted on a red granule ; the long cilium
in front moves rapidly, while the posterior
short one is motionless. See FUCACEJE.

BIBL. Harvey, Mar. Alg. pi. 1 B ; Phyc.
Brit. 133, &c. ; Thuret, Ann. Sc. Nat. 3 se"r.
xvi. pp. 7 & 10.

CYSTOTRICHA.

[ 233 ]

CYTHERURA.

C YSTOT'RICHA, Berk, and Broome.—
A supposed genus of Sphaeronemei (Conio-
mycetous Fungi). Minute fungi forming-
dots or lines upon wood from which the
bark has been stripped. Only one species
is described.

<?. atooJa,Berk. and Br. Perithecia black,
with a reddish tinge, opening by a reddish
disk.

BIBL. Berk. andBr. Ann. N. H. 1850, v.
457, pi. 12. fig. 10.

CYTH'ERE, Miill.— A genus of Ento-
mostraca, of the order Ostracoda,and family
Cytheridae.

Char. Shell usually hard, calcareous,
rough and uneven ; mouth with a lip and
labrum ; masticatory organs well developed ;
mandibles toothed at the end 5 lower an-
tennas four-jointed; upper antennae five-
jointed, last three joints elongated, spini-
ferous ; feet in the male and female alike ;
internal lobe of the first pair of maxillae
well developed. Not capable of swim-
ming.

Those having the valves almost regularly
oblong, with the surface very irregular,being
wrinkled, ridged, and beset with tubercles,
and crenulate or strongly toothed on the
margin, have been separated by Rupert
Jones under Cythereis.

46 living British species. Many fossil
Cytheras are recorded, which, however,
most probably belong to allied genera, un-
distinguishable by the valves alone. Brady
records 22 species as occurring in post-ter-
tiary deposits of Britain.

BIBL. Baird, Brit. Entom. 163 ; Brady,
Linn. Tr. xxvi. 394, and Ann. N. H. ser. 4.
ix. 68 ; Zool. Tr. v. 376.

CYTHERE'IS, Rup. Jones. See CY-

THEBE.

C YTHEREL'LA, R. Jones and Bosquet.
— A genus of Ostracode Entomostraca, fa-
mily Cytherellidae.

Char. Valves unequal, very thick and
calcareous, not notched in front. Upper
antennae very large, seven- jointed, and geni-
culate at the base ; lower broad, flattened,
and two-branched; mandibles very small,
with a large pectinate-setose palp; three
pairs of hinder limbs, scarcely pediform, the
two anterior pairs branchial, the others
rudimentary. Abdomen terminating in two
very small, narrow, spiniferous laminae.
Ova and embryos borne beneath the shell
of the female.

2 living British species, C. scotica and C.
lcevis; from deep dredging in the Minch.

Numerous fossil species, from the Carboni-
ferous to Tertiary strata inclusive.

BIBL. Brady, Linn. Tr. xxvi. 472 ; Zool.
Tr. v. 362 ; R. Jones, Mon. Cret. Entom.
1849, 28 ; Mon. Tert. Entom., Palaont. Soc.
1856, 54.

C YTHERELLITN" A, Jones.— An obscure
fossil Ostracod, very common in the upper
Silurian strata of Britain and Europe.

BIBL. R. Jones, Ann. N. H. ser. 4. iii.
215.

CYTHERID'EA, Bosquet.— A genus of
Ostracode Entomostraca, family Cytheridae.

Char. Shell subtriangular, thick and com-
pact, smooth, pitted, papillose or rugose.
Mouth with a lip and labrum ; masticatory
organs well developed ; mandibles toothed
at apex j lower antennae four-jointed ; upper
five-jointed, last three joints elongated,
spiniferous ; feet in male and female unlike ;
right foot of first pair in the male prehen-
sile, right of the second pair weak and
rudimentary.

10 living British species. Several fossil
Cretaceous and Tertiary species.

BIBL. Brady, Linn. Tr. xxvi, 421 ; Zool.
Tr. v. 370 ; R. Jones, Mon. Tert. Entom.,
Pal. Soc. 1856, 40, and Geol. Mag. vii. 76,
158.

CYTHERIDE'IS, Jones.— A subgenus
of Ostracode Entomostraca.

1 living British species, C. subulata',
some fossil reputed species, Cretaceous and
Tertiary.

BIBL. Jones, Monogr. Tert. Entom., Pa-
Iceontog. Soc. 1856, 46 (shell) ; Brady, Ann.
N. H. 1872, ix. 58 (animal).

CYTHEROPSIS, Sars = Eucythere,
Brady.

CYTHEROP'TERON, Sars.— A genus
of Ostracode Entomostraca.

Char. Valves of shell unequal, with pro-
minent lateral alae. Mouth with labium
and labrum ; masticatory organs well deve-
loped ; mandibles toothed ; lower antennas
five-jointed; upper five-jointed; postabdo-
minal lobes broad and short, with three
setae ; eyes none.

9 living British species. Also some Cre-
taceous and Tertiary species.

BIBL. Brady, Linn. Trans, xxvi. 447,
and Ann. N. H. 1872, ix. 61 ; R. Jones,
Geol. Mag. vii. 76 and 158.

C YTHERU'RA, Sars.— A genus of Os-
tracode Entomostraca.

Char. Shell oblong or subtriangular, pos-
terior extremity prolonged into a beak. Su-
perior antennae six-jointed, shortly setose,

CYTISPORA.

[ 234 ]

DACTYLIUM.

tapering; inferior antennae five-jointed;
terminal claws short ; mandibles robust ;
teeth blunt ; eyes two.

24 living British species ; also some Cre-
taceous and Tertiary species.

BIBL. Brady, Linn. Tr. xxvi. 439, and
Ann. N. H. 1872, ix. 55 ; R. Jones, Oeol
Mag. vii. 77, 158.

CYTIS'PORA, Ehrenb.— A genus of
Sphaeronemei (Coniomycetous Fungi), re-
markable for emitting the minute bodies
formerly regarded as spores, agglutinated
together into a more or less gelatinous mass,
in the form of a tendril. The relationship
between the forms called Cystispora and va-
rious species of Sphceria has long been no-
ticed ; and Fries stated that he had seen C.
leucostoma pass into S. leucostoma. C.fugax
was stated by Berkeley to be exactly ana-
logous to S. salicina. Kecent researches
seem to prove that the present genus, with
Septoria and others, are really only forms
belonging to various Ascomycetous Fungi,
and that they bear the same relationship to
the latter as the spermogonia of LICHENS
do to the theciferous fructification. Hence
the so-called spores of Cytispora &c. ap-
pear in reality to be the spermatia or stylo-
spores of the Sphaeriacei. As these ques-
tions are not yet completely worked out,
we retain the names of these pseudo-genera
and species at present. See SPHJERIACEI.

Cytispora ruoescens,~Fr. Disk dirty brown;
spores (?) reddish. On Rosaceae.

C. chrysosperma, Pers. Disk black;
spores yellow. On Poplar bark.

C. carphosperma, Pers. Disk dingy;
spores straw-coloured. On Hawthorn and
other Rosacse.

C, leucosperma, Pers. Disk dirty white ;
spores white. On various trees. Common.
Nemasporum rosarum, Grev. Scot. Crypt.
Fl. t. 20.

C. fuyax, Bull. Disk dirty brown;
spores pale. On Willow branches. Very
common.

C. orbicularis, Berk. Disk yellowish;
spores pale vinous red. Upon small orange
gourds. Berkeley, Ann. Nat. Hist. i. pi. 7.
fig. 6.

C. Hendersoni, Berk, and Broome. Disk
whitish; spores large, dirty white. On
Dog-rose. Berk, and Br. Ann. Nat. Hist.
2 ser. v. 379.

C. pulveracea,Berk. Br. Flora = Ceutho-
spora phacidioides, Desm.

BIBL. Berkeley, Brit. Flor. vol. ii. pt. 2.
281, Crypt. Bot. 331 ; Berk, and Broome,

1 Hooker's Jn. of Bot. iii. 319 ; Tulasne, Ann.
Sc. Nat. 3 s<§r. xv. 375 (Ann. N. H. 2nd
ser. viii. 114) ; Ann. Sc. Nat. xx. 129 ;
ibid. 4 ser. v. 115 ; Bot. Ze.it. xi. 49 (1853).

CYTOBLAST. See NUCLEUS.

CYTOBLASTE'MA, BLASTEMA, or
PROTOPLASM. — The amorphous proteine-
substance of which animal and vegetable
cells are more or less entirely composed.
See CELLS, and PROTOPLASM.

CYTODE.— A term applied by Hackel
to an organism consisting of a simple lump
of sarcode = to our protoplast (1850).

BIBL. Hackel, Gen. Morph. i. 269.

CYTOLEI'CHUS, M6gn.— A genus of
Acarina, near to Sarcoptes.

C. sarcoptoides, has the body rounded,
the rostrum obtuse, and the tarsus of the
2nd pair of legs with a short cirrus directed
upwards or outwards. In the air-sacs and
bronchi of the Gallinae.

BIBL. Me*gnin, Parasites, 153.

D.

DACRY'MYCES, Fries.— A genus of
Tremellini (Hymenomycetous Fungi), con-
sisting of lobulated gelatinous bodies grow-
ing upon wood. D. stittatw, a very com-
mon species on moist rotting wood, is
orange, turning brown when dried. Tu-
lasne has published some curious ob-
servations on this genus, showing that the
spores produced on the basidia of the
external hymenial layer, are of two kinds ;
of which one kind germinates, while the
other produces minute stalked bodies, one
from each chamber of the septate spore,
destitute of gernrinative power (spermatia ?)
(PI. 27. fig. 5).

BIBL. Berkeley, Hook. Brit. Fl. v. pt. 2.
210; Crypt. Bot. 353; Greville, Sc. Crypt.
Fl. pi. 159 ; Tulasne, Ann. Sc. Nat. 3 se*r.
xix. 211, pi. 12&13.

DACTYLI'NA,Nyl.— A doubtful genus
of Lichens.

D. arctica, Hook. , a singular fungus-look-
ing plant, inhabits Arctic America.

BIBL. Leighton, Linn. Jn. ix. 192, pi. 2.
figs. 11-17.

DACTYL'IUM,Nees.— A genus of Muce-
dines (Hyphomycetous Fungi), nearly allied
to Trichothecium, consisting of moulds
growing over decaying plants. Fries refers
Corda's species of Dactylium to Dendry^
phium. One species, Dactylium oogenum,
Montagne, is remarkable for its place of

DACTYLOCOCCUS.

[ 235 ]

DAPHNELLA.

Fig. 15-5.

On decaying agarics,
Grev. Sc. Crypt. Fl.

occurrence : it grows upon the surface of
the membrane within the shell of the eggs
of fowls and other birds. It
does not appear to have been
observed in this country ; but
several foreign writers have
investigated it ; and from the
experiments made by Spring
and Wittich, it appears that
the spores pass through ori-
fices existing in the shell, and
germinate in the interior,
often in the air-chamber. A
full account of this plant, and
of the literature, is given by
Ch. Robin. Many of the
species are undoubtedly coni--^ lium atrum>
diiferous forms of Sphcence A fertile flla-
(Tulasne, Carpologid). See ment with septate
DENDRYPHIUM and HELMIN- Kec3hesP°n ita

THOSPORIUM. British Spe-Magn.200 diams.

cies :

D. pyriforme, Fr. On mouldering stems
of herbaceous plants.

D. macrosporum, Fr. On rotton wood,
leaves, and fungi.

D. dendroides, Fr.
&c. Very common,
pi. 126. fig. 1.

D. obovatum. Berk. On willow twigs, in
damp. Ann. Nat. Hist. vi. pi. 14. fig. 26.

D, sphcerocephalum, Berk. On dead ivy-
twigs, L c. fig. 27.

D. tenettum, Fr. On moss.

BIBL. Berk, in Hook. Brit. Fl. v. pt. 2.
345 ; Ann. N. H. ut supra ; Berk, and
Broome, Ann. N. H. 2 ser. vii. 102 ; Robin,
Parasites, 2nd ed. 543, pi. 2. figs. 5 & 6 ;
Fries, Syst. Myc. iii. 414 j Summa Veget.
491.

DACTYLOCOC'CUS,Nag.— A genus of
Palmellaceous Algae, allied to CJiaracium
and Hydrianum.

Char. Cells oblong or fusiform, free, 2-8
together, then separating. Two species,
one green ; among other Algae, or on the
side of pools ; about 1-2500" long.

BIBL. Nageli, Einz. Alg.- p. 85 ; Raben-
horst, Fl. Alg. iii. p. 46 (fig.).

DACTYLOP'ORA, Lam.— Regarded by
some as one of the Foraminifera imper-
forata ; but by others as belonging to the
calciferous Algae. The simplest form pre-
sents a set of sac-like chambers, side by
side, for a part or the whole of a circle,
with their mouths in one direction along
the inner median line. Various modifica-
tions lead to the structure of a cylinder of

such rings, with interspaces, thickened
walls, and subsidiary cavities. The simple
forms (D. eruca, PI. 23. f. 63) live in the
tropical seas. The more complicated species
are of Tertiary age in France, Italy, and
San Domingo ; D. reticulata (PI. 23. f. 54)
is one of these.

BIBL. Parker and Jones, Ann. N. H.
ser. 3. 473; Carpenter, For. 127;Gumbel,
Abh. lay. Akad. 1872.

DACTYL'OPUS, Glaus.— A genus of
Entomostraca, order Copepoda.

D. tisboides. Marine.

BIBL. Glaus, Copepod.I27 '; Brady, Trans.
Northumberland.

DALTO'NIA,Hook. andTayl.— A genus
of Pleurocarpous Mosses, the species given
being restored here on account of the struc-
ture of the leaf ; while D. heteromalla of
Hooker goes to Hypnum on the same
ground.

D. splanchnoidesjllook. &nd.T.=Hookeria
splanch. Hook.

DAM^E'TJS, Koch. See BELBA.

DAM'MARA-"£ww." — The resin of
Dammara australis, N. O. Pinaceae. It is
often used, dissolved in benzole, as a
varnish ; and as it dries quickly, it is useful.
It is also largely used as a substitute for
Canada balsam ; but we prefer the latter.

DANJE'A, Smith. — A genus of Marat-

Fig. 156.

Danaea.

Part of a pinnule with sori.
Magnified 5 diameters.

tiaceous Ferns, whence the family is some-
times called also Dangeaceee. Tropical Ame-
rica.

12 species.

BIBL. Hooker and Baker, Syn. 442.

DAPH'NE, L. See THYMELEACEJE.

DAPHNEL'LA, Baird.— A genus of
Entomostraca, of the order Cladocera, and
family Daphniadae.

Char. Inferior antennae very large, pos-
terior branch two-jointed only.

DAPHNIA.

[ 236 ]

DASYA,

D. Wingii (PI. 20. fig. 27). Fresh-
water.

BIBL. Baird, Brit. Entomos. 109.

DAPH'NIA, Mull.— A genus of Ento-
mostraca, of the order Cladocera, and family
Daphniadae.

Char. Head produced into a more or less
prominent beak ; superior antennae situated
beneath the beak, either one-jointed or con-
sisting of a minute tubercle with a tuft of
short filaments ; inferior antennae large and
powerful, two-branched; one branch three-
jointed, the other four-jointed; five pairs
of legs.

Valves of the carapace finely reticulated,
and terminated below by a longer or shorter
serrated spine. Anterior branch of inferior
antennae (PI. 20. fig. 286) four-jointed, first
joint very short; from the end of the third
a long filament arises ; and the fourth joint
is terminated by three others ; posterior
branch three-jointed, the first and second
joints sending off a long filament, the third
terminated by three of them ; the filaments
are jointed near the middle, and usually
feathery. Eye spherical, with about twenty
lenses. Labrum (PI. 20. fig. 35) flattened,
and with a large hairy lobule at the end.
Mandibles (PI. 20. fig. 34) consisting of a
fleshy -looking body, bent inwards near the
end, and terminated by numerous minute
teeth. Jaws (PI. 20. fig. 36) composed of a
strong body terminated by four horny spines,
three of which are curved inwards. Legs five
pairs, those of the first pair in the female
(PI. 20. fig. 29) three-jointed; upon the
outer edge of the second joint are three
small projections, each with four or five
long jointed setae; terminal joint very
small, and with one or two similar setae ;
the setae not plumose. In the male they
are more slender, with "a strong claw at the
end of the second joint, while the seta
arising from the terminal joint is very long,
nearly the length of the body, and" floats
outside the shell.

The second (PI. 20. fig. 30), third (fig. 31),
and fourth (fig. 32) pairs of legs are bran-
chial and somewhat similar, the joint fur-
nished with jointed and mostly plumose
setae, and a branchial plate also giving off
numerous plumose setae. The fifth pair of
legs (fig. 33) are three-jointed, the portion
correspondingto the branchial plate rounded
and without filaments; above this is a
curved, jointed, and plumose spine, the
third and fourth joints forming finger-like
processes springing from the lower end of

the leg, with two or three plumose setae.
The branchial legs are constantly in motion
during life; and this gives rise to the
quivering appearance seen in the Daphnue
with the naked eye or a simple lens.

The ova on their escape from the body
become lodged between the back of the ani-
mal and the shell, where they remain until
completely hatched ; but at certain seasons
of the year ephippial or winter ova (PI. 20.
fig. 37) are produced (ENTOMOSTBACA).

According to Lubbock's observations, the
latter only are true ova ; although both
kinds become hatched and perfectly deve-
loped, this may occur without impreg-
nation.

Seven British species of Daphnia are re-
cognized : some of them may be found in
almost every collection of water, which they
frequently colour.

D.pulex (PI. 20. fig. 28) (common water-
flea). Valves oval, their dorsal margin not
serrated ; head large, rounded above and in
front ; superior antennae (PL 20. tig. 28 a)
very small; filaments of inferior antennae
plumose ; posterior portion of abdomen with
four projections at its curve, the first pro-
longed and bent upwards ; below these are
two jointed filaments ; the end portion has
two dentate arches, and
terminates in two strong
hooks.

Some other species are
common ; but their essen-
tial characters have not
been briefly expressed.

BIBL. Baird, Br. En-
torn. 89; Lubbock, Ann.
N. H. 1857, xx. 257;
Leydig, Daphnid. 1860;
Weismann, Daphniden,
1877, and Zeitschr. wiss.
Zool. 1876, 7.

DARWINEL'LA,
Brady, ( = PolycMes, B.).
— A genus of Ostracode
Entomostraca.

1 British species: D.
Stevewoni.

BIBL. Brady, Ann.
N. H. ser. 4. vi. 25.

DA'SYA, Ag.— A ge-
nus of Rhodomelaceae Dasya KUtzingiana,

(Florideous Algae), con- with a stichidium

. ,. e , f, P ni and two rows of

sistmg of tufted hlamen- tetraspores.
tous sea- weeds, of a red, Magnified so dia-
brown, or purple colour,
growing on rocks near low- water mark.

Fig. 157.

DASYDYTES.

[ 237 ] DEGENERATION, FATTY.

The principal filaments are stoutish,
branched,andclothedwith branched ramules,
upon which are borne the stichidia contain-
ing tetraspores (fig. 157), or ceramidia con-
taining spores, on distinct plants. Four
British species are recorded, of which D.
coccinea and D. Arbmcula (PI. 4. fig. 9) are
the commonest.

BIBL. Harvey, Mar. Alga. 93, pi. 12 B ;
Phyc. Brit. pi. 40, 224, 225 & 253.

DASY'DYTES, Gosse.— A genus of Ro-
tatoria, of the family Ichthydina.

Char. Eyes absent ; body furnished with
bristle-like hairs ; tail simple, truncate.

I), goniathrix. Hairs long, each hair
bent at an abrupt angle j neck constricted j
length 1-146" ; fr. wat.

D. antenniyer. Hair short, downy ; a
pencil of long hairs at each angle of the
posterior extremity of the body j head with
two club-shaped organs resembling antennse ;
length 1-170".

BIBL, Gosse, Ann. N. H. 1851, viii. 198.

DASYGLCE'A, Thwaites.— A genus of
Oscillatoriaceae (Confervoid Algee).

D. amorpha (PL 8. fig. 11) forms a shape-
less gelatinous stratum, consisting of curled
and entangled filaments, with very large
sheaths, open at the ends ; in marshy places.

BIBL. Eng. Sot. Stipp. £941 ; Kiitzing, Sp.
Alff. 272 ; Tab. Phyc. Cent. i. pi. 72. fig. 2.

DATE.— The fruit of the Date-palm,
Phoenix dactylifera, N. 0. Palmacese.
Roasted dates are used to adulterate real
coffee j a so-called date-coffee is also manu-
factured from the entire fruit, or from the
seed (perisperm) only. The principal tissues
of the latter are represented in PI. 2. fig. 9.

DAVAL'LIA, Sm. — A very large genus ;
tropical.

BIBL. Hooker, Syn. 88.

DAVALL'IE^E.— A family of Polypo-
diaceous Ferns.

Fig. 158.

Fig. 159.

Davallia pyxidata.

A pinnule with sori.
Magn. 5 diam.

Davallia. Sori globose or elongate, intra-

A sorus with the

indusium cut open.

Magn. 15 diam.

or sub-marginal ; indusium terminal on the
veins; somewhat urn- or cup-shaped, the
mouth truncated (figs. 158 and 159), apex
free ; veins pinnate.

Cystopteris. Sori globose, on the back of
the veins ; involucre membranous, sub-or-
bicular, inserted by its broad base under the
sorus, which at the beginning it covers like
a hood ; fronds two or three times divided,
thin, veins free.

DEGENERATION, FATTY.— The ab-
normal deposition of free fatty matter in the
histological elements of animal bodies.

When, from whatever cause, the normal
functions of the morphological element of
a tissue — cells, or the secondary deposits
formed in them — become languid or inter-
rupted, free globules of fat or oil become
deposited in them ; and as this fatty matter
increases in amount, the tissue loses to a
greater or lesser extent its natural vital and
physical properties j hence it is said to be in
a state of fatty degeneration. The discovery
of the fatty degeneration of tissues is pro-
bably one of the most valuable fruits of
microscopic study in regard to medical
science ; for it has shown us that maladies
supposed formerly to arise from too great
abundance of the circulating fluid, have really
had their origin in a decayed state of.the tubes
or vessels in which the fluid was contained,
and that the natural process of human decay,
as it is called, is a morbid process or disease,
probably to a certain extent as remediable
or preventible as many other diseases to
which man is naturally liable. Here is
indeed a matter of deep interest.

In addition to the deposition of fat within
the elements of a tissue undergoing fatty
degeneration, amorphous finely granular
proteine-matters are sometimes found ; oc-
casionally also brown, yellow, red, or black
granular pigment is met with (pigmentary
degeneration), together with amorphous or
crystalline calcareous salts, as the carbonate
and phosphate of lime &c. (calcareous de-
generation) ; sometimes the fatty matter is
crystalline, it then generally consists of
cholesterine.

Fatty degeneration of cells is well seen in
those of the liver when undergoing this
change. In the normal state, these as well
as most cells, except those of true fatty tis-
sue, contain merely one or two very minute
or no globules of fat, — whilst in the dege-
nerated tissue they contain a considerable
number of larger or smaller globules (fig.
160). At the same time, the cell-walls and

DEGENERATION, FATTY. [ 238 ] DELESSERIACE^E.

nuclei become thinner and paler, or atro-
phied. A similar state to that which is
abnormal in man, is normal in the lower ani-
mals. Sometimes the substance intervening
bet ween cells becomes degenerated; and thus

Fig. 160.

Cells of the human liver; a, nearly normal cells; b,
cell with pigment granules ; c, cells containing fatty
matter.

Magnified 400 diameters.

we have intercellular fatty degeneration
(PL 38. fi£. 15). Other instances of fatty
degeneration are noticed under the respective
heads of the tissues £c., as the Graafian
vesicles and the cells of the corpora lutea
(OVAHY), the epithelia of the mucous and
serous membranes, and of the various glands,
the vessels, the exudation-corpuscles of in-
flammation, the muscles, &c.

The fatty degeneration of the capillaries is
represented in PL 38. fig. 13. In the larger
blood-vessels, when reaching a more ad-
vanced degree, it forms atheroma.

It might appear paradoxical to regard the
presence of numerous fat-globules, in such
instances as the cells of cancer, and the
exudation-cells of inflammation, where the
vital processes are so evidently augmented,
as indicating a state of degeneration. But in
these, as in other instances, the functions of
the cells, after the latter have attained their
full development, cease, and the cells un-
dergo degeneration and decay.

The free fatty matter is probably derived
in general from the liberation of that pre-
viously dissolved in the contents of the
cell ; but it may be produced by the for-
mation of fatty matter from the proteine or
other constituents of the cell -contents. It
is curious that portions of the flesh and
other proteine-components of one animal,
when kept in the peritoneal cavity of another
living animal, will undergo fatty degenera-

tion. The formation of adipocere seems to
be an instance of post-mortem fatty dege-
neration.

Amyloid degeneration is noticed under
AMYLOID.

BIBL. Virchow, Path. Cell. 1861 ; Wedl,
Path. Hist.-, Forster, Spec. Path. Anat.\
Wagner, Nachr. d. Ges. d. Wiss. z. Gb'ttin-
ffen, 1851 (Chem. Gaz. ix. 309); Green,
'Path. 31, 1871 ; Rindfleisch, Lehrb. Geweb.
1878, 46.

DELAVA'LIA, Brady.— A genus of En-
tomostraca, order Copepoda.

D. palustris. Northumberland.

BIBL. Brady, Trans. Northumberland $c.,
& Copepoda (Ray Soc.).

DELESSE'RIA, Lamx.— A genus of De-
lesseriaceae (Florideous
Algae), consisting of Fig. 161.
sea-weeds with a flat,
membranaceous, rose-
coloured frond, having
a percurrent midrib,
growing on rocks or
on other larger Algae,
mostly from 2 to 8
inches high. Six spe-
cies are described as
British, most of them
common. The leaf -like
lobes of the frond arise
from a kind of stalk, or
from the midribs of ,
older lobes. The tex- ,^el?88e™
ture is densely paren-'
chymatous throughout. Nat. size. '

D. sanguinea (PI. 4. fig. 5) ripens its fruit
in the winter ; and then the membranous
part of the fronds decays, leaving the midribs
clothed with tufts of the sporophylls or leafy
lobes containing the tetraspores (fig. 161),
and stalked coccidia containing the spores.
The fructification is somewhat similar in
D. alata^ while in D. sinuosa the coccidia
are immersed in the frond, and the tetra-
spores in cilia-like processes fringing its
margin; and in D. Hypoglossum the coc-
cidia are seated on the midrib, and the
tetraspores arranged in longitudinal linear
rows like sori on each side of the midrib.

BIBL. Harvey, Mar. Algce, 113, pi. 15 Aj
Phyc. Brit. pis. 2, 26, 83, 151, 247, 259 ;
Greville, Alg. Brit. pis. 72-74, 76.

DELESSERIA'CE^E.— A family of Flo-
ridese. Rosy or purplish red, or blood-red
sea-weeds, with a leafy, or rarely filiform,
areolated, inarticulate frond, composed of
polygonal cells. Lobes of the frond deli-

DELTOMONAS.

[ 239 ]

DEMATIEI.

cately membranous. Fructification double ;

1. Conceptades (coccidia) external, or half-
immersed, hemispherical, usually imperfo-
rate, containing beneath a membranous peri-
carp a tuft of dichotomous filaments, whose
articulations are finally changed into spores.

2. Tetraspores in distinctly definite son,
either scattered through the frond or placed
in proper fruit-lobes or sporophylls.

Synopsis of British Genera.

Delesseria. Frond leafy, of indefinite
form, with a percurrent midrib.

Nitophyllum. Frond leafy, of definite form,
without a midrib (sometimes traversed by
vague, vanishing nerves).

Plocamium. Frond linear or filiform,
compressed, much branched, distichous;
ramuli pectinate, secund.

BIBL. See the genera.

DELTO'MONAS, Kent.— A genus of
Flagellate Infusoria.

Char. Bodies variable, wedge-shaped,
stalked; flagella two, equal. Freshwater.
Multiplication by longitudinal and trans-
verse division, and the breaking up of the
body into germs. In ponds. (Kent, In/". 283.)

DEMATIE'L— A family of Hyphomy-
cetous Fungi, growing on the dead parts of
plants, and characterized by the mostly
septate spores being attached to rigid thick-
walled filaments, which are continuous or
septate.

According to the observations of Tulasne,
many of the supposed genera of this family
are merely conidiiferous states of Ascomy-
cetous Fungi; for instance Cladosporium.
We enumerate them here according to the
older arrangement, as their history is not
yet fully cleared up.

Synopsis of British Genera.

Cephalotrichum. Fertile filaments stalk-
like, erect, septate, terminating in a globose
capitule formed by radiating forked or
ternate branches bearing globular spores
at their tips.

Sporocybe. Filaments rather fibrous,
subulate, capitate, bearing simple spores
conglobated into a terminal head.

GEdemium. Filaments rigid, erect, al-
most continuous, or annulated, bearing at
the sides globular masses of spores.

Myxotrichum. Filaments erect, scarcely
septate ; fertile branches crowned by globules
of heterogeneous conglutinate spores.

Helminthosporium. Filaments erect,
simple, septate ; spores transversely septate.

Bolacotricha. Filaments simple, uni-
formly articulate at the apex ; spores con-
glomerated, large, globular, shortly stalked,
contents distinctly granular.

Triposporium. Filaments erect, sep-
tate, sterile branches solitary, more or less
spreading ; fertile branches shorter, bearing
at the tips solitary, stellate, mostly very
shortly stalked spores.

Helicosporium. Filaments erect, subu-
late, closely septate, continuous and dia-
phanous at the summit ; spores thread-like,
septate, spirally coiled, then expanding
themselves with elasticity.

Cladotrichum. Filaments erect, septate,
branched ; branches and branchlets bearing
septate spores at their tips.

Dematium. Filaments erect, septate,
with verticillate branchlets below, simple
and whip-like above ; spores crowded on the
apices of the ramules.

Cladosporium. Filaments erect, septate
above, bearing the spores arranged in rows
forming short moniliform branchlets.

Macrosporium. Filaments suberect, sep-
tate, delicate, evanescent, bearing erect,
stipitate spores, with many transverse and
usually some longitudinal septa.

Arthrinium. Filaments tufted, suberect,
annulate, with opaque thickish septa;
spores fusiform, septate, large.

Camptoum. Filaments as in the pre-
ceding ; spores ovate, curved, small.

Arthrobotryum. Common stem com-
posed of jointed filaments. Spores large,
radiating, so as to form a little head, dark,
septate.

Dendryphium. Filaments free, jointed,
simple below, branched above ; branches
and branchlets often monilioid ; spores sep-
tate, acrogenous, concatenated.

Periconia. Stem composed of fasci-
culated compacted filaments ; head globose ;
spores fixed to the free tips of the fila-
ments.

Haplographiwn. Filaments jointed, free,
black ; spores concatenate, hyaline.

Monotospora. Filaments free, black,
bearing one or rarely two (by division)
large, black, subglobose spores at their
tips.

Helicoma. Filaments erect, dark, jointed,
bearing on their sides pale, flat, spiral
spores.

Polythrincium, Filaments moniliform;
spores springing from the midst of the fila-
ments, didymous.

Gonatosporittm. Filaments erect, jointed,

DEMATIUM.

[ 240 ]

DEMODEX.

thickened at the articulations j spores
irregularly biconical, somewhat angular,
attached in whorls.

Sporodum. Filaments erect, jointed ;
threads of inarticulate spores moniliform,
seated towards their base.

Allied or uncertain Genera.

Blastotrichum. Pedicels ascending or
floating, very much branched, continuous ;
spores oblong, transversely septate.

Stachyobotrys. Pedicels branched, sep-
tate ; branches crowded at the tips with
whorls of Hiainniillary very short branchlets
forming a capitulum ; spores didymous.

Helicotrichum. Filaments creeping,
branched, septate only at the tips j spores
spirally curled, somewhat septate.

DEMA'TIUM, Pers.— A genus of Dema-
tiei (Hyphomycetous Fungi), growing upon

Fig. 162. Fig. 163. Fig. 164.

Dematium griseum. Magnified 200 diameters.

dry leaves, bark, &c., distinguished by the
sporiferous branchlets arising closely toge-
ther near the base of the erect filaments.
British species :

D. griseum, Pers. (figs. 162-4). On
rotten hazel-stumps. Cheetopsis Wauchii,
Grev. Sc. Crypt. Fl. pi. 236. See ECHINO-

BOTRYUM.

BIBL. Berk. Hook. Brit. Fl. v. pt. 2, 338 ;
Ann. N. H. i. 260, vi. 435 ; Grev. /. c. ; Fries,
Sum. Veg. 499 j Corda, Ic. Fung. i. pi. 4.
figs. 242, 243.

DEMO'DEX, Owen (Simonia, Gerv.).—
A genus of Arachnida, the exact systematic
position of which is doubtful, "although
usually placed in the family Acarina.

Char. Legs terminated by two claws
(only one, Beck), no acetabula; abdomen
annulose.

D.foUiculorum (PI. 6. fig. 42), the Aca-
rus, Simonia, or Entozoon foUicidorum of
some authors, inhabits the 'sebaceous and

hair-follicles of the human skin. The mi-
nute size of the various parts renders it ex-
tremely difficult to isolate them. It varies
in length from about 1-150 to 1-50".

At the anterior part of the body are two
two-jointed organs (PI. 6. fig. 43 a), the basa
joint longest, the distal smallest, and ter-
minated by a strong claw ; these appear
to represent maxillary palpi. Between
these are two narrow elongated organs (fig.
43 6), the mandibles. Behind these is a
triangular labrum (fig. 43 c) ; a labium has
also been described.

Above or upon the basal joint of the palpi
are two minute tubercles, one on each side
(fig. 43 d). Similar tubercles are seen upon
the dorsal surface of the thorax, between
the second and third, and the third and
fourth pairs of legs.

On each side of the thorax are four pairs
of very short conical legs ; these are appa-
rently three-jointed, and marked by irregular
fine transverse striae.

The abdomen is longer than the thorax,
tapers posteriorly, and exhibits indications
of transverse rings, in the form of numerous
delicate transverse lines.

These animals may be obtained by press-
ing out the contents of the follicles existing
upon the sides and alae of the nose, especially
when these appear enlarged, whitish, and
exhibit a terminal black spot. A drop of oil
should then be added to the secretion, and
the whole allowed to macerate for some
hours at a gentle heat. Or the secretion
may be digested in a mixture of alcohol and
ether, to dissolve the fatty matter, and then
treated with solution of potash.

The secretion contains the ova, the young
animals, and the exuviae. When contained
in the follicles, the tail is directed towards
their orifice.

Var. caninus occurs in the pustules of the
skin of the dog affected with the " mange."
The average size of this is less than that of
D.foUiculorum, amountingto 1-150 to 1-100"
in length. It does not appear to constitute
a distinct species ; for Gruby found that,
by inoculating the dog with the human
parasite, a disease resembling, if not identi-
cal with, the mange was produced.

Var. cati, on the cat ; about ± less than
D.foUiculorum.

BIBL. Simon, Mutter's Archiv, 1842,218;
Owen, Hunt. Lect. i. 251 ; Gervais, Walck-
enaer's Apteres, iii. 282 ; Wilson, Tr. Hoy.
Soc. 1844, 305 ; Tulk, Ann. N. H. 1844,
xiii. 75; Gruby, Ed. Mn. Jn. vii. 333;

DENDRITINA.

[ 241 ]

DEEMANYSSUS.

Wedl, Path. Hist. 803; R. Beck, Achr.
Micr. 6, pi. 24. fig. 1 ; Megnin, Parasites.
265.

DEXDRITI'NA, D'Orb.— The nautiloid,
or compactly discoidal, condition of Pene-
roplis. Common in tropical seas.

BIBL. Carpenter, Introd. For. 88.

DENDROCOME'TES, Stein.— A doubt-
ful genus of Acinetina. The single species,
D. paradoxus (PI. 32. fig. 36), is supposed
by Stein to constitute the resting stage or
Acineta form of Spirochona gemmipara. It
is found upon the gill-plates of Gammarus
pulex.

BIBL. Stein, Siebold # Kolliker^s Zeitschr.
1852, iii. 492 ; id. In/us. 205 ; Kent, Inf.

DENDRO'MONAS, Stein.— A genus of
Flagellate Infusoria.

Char. Bodies pyriform, obliquely trun-
cate, single at the ends of a rigid homo-
geneous branched pedicle ; flagella two ; one
long, and the other short, lateral. Fresh-
water. 2 species. (Kent, Inf. 265).

DENDROSO'MA, Ehr.— A genus of
Rhizopoda, of the family Acinetina.

Char. Consists of a thick branched pedicle,
fixed at its base, the branches supporting at
their ends numerous bodies, a little larger
than the pedicles, each resembling an Ac-
tinophrys.

I), radians. Bodies conical, thick, soft
and smooth, alternately branched ; branches
incrassate and tentaculate at the ends. Size
1-96' '. Freshwater.

BIBL. Ehrenberg, Infus. 316; 01. &
Lachm. Inf. iii. 140 (fig.).

DENDRYPHIUM, Wallr.— A genus of
Dematiei (Hynhomycetous
Fungi), consisting of moulds
growing over dead herba-
ceous plants, nearly related
to Dactylium ; but there are
often several spores chained
together at the tips of the
branches; perhaps not di-
stinct from Brachycladium,
Corda, whose species of Dac-
tyUwn(&g. 165) are brought
under this genus by Fries.
British species :

D. curtum, Berk, and
Br. On dead stems. Ann.
N. H. 1851, vii.pl. 6. fig. 9.

D. laxum, Berk, and
Br. On dead stems. L. c.

fig. 10. Magn. 200 diams.

°D. griseum, Berk, and Br. On dead stems.
L. c. fig. 11.

Fig. 165.

BIBL. Berkeley and Broome, I. c. 176,
pi. 6 ; Fries, Summa Veget. 504.

DENTALI'NA, D'Orbigny.— The bent,
oblique, and somewhat excentric varieties
of Nodosaria pass under this name for con-
venience rather than for zoological reasons.
Innumerable modifications of these Curved
and tapering stichostegian Foraminif era oc-
cur in all formations from the Carbonifer-
ous to the Tertiary, and abound in existing
seas. D. communis, D'Orb. (PI. 23. f. 33)
is the type, and has persisted the longest of
any.

BIBL. D'Orb. For. Foss. Vien. 1846;
Williamson, Rec. For. 17 ; Morris, Brit.
Foss. 34 ; Carpenter, Foram. 163 ; Jones,
Parker, and Brady, Monog. Foram. Crag,
Pal. Soc. 1866, 53, &c.

DENTALINOP'SIS, Reuss.— A sticho-
stegian Nodosarina, commencing in its
growth as a Rhabdogonium (Ch'thocerina),
and continuing as a Dentalina, Only fossil j
Cretaceous.

BIBL. Reuss, Site. Ak. Wien, xliv. 367.

DENTIOEL'LA, Ehr. See BIDDULPHIA.

DENTIC'ULA, Kiitz.— A genus of Dia-
tomacese.

Char. Frustules free, single or binate,
straight, oblong or linear in front view ;
valves elliptical or narrowed at the ends,
transversely striated. Freshwater.

Striee mostly coarse, not resolvable into
dots (costse) ; valves without a median line
or nodules ; ends of the strise visible at the
margins of the front view of the f rustules ;
no internal septa.

Five British species. Seven European
species ; one fossil (California).

D. obtusa (PI. 16. fig. 25 : d, front view ;
c, valve). Valves lanceolate, attenuate and
obtuse at the end ; length 1-330".

The other species differ principally in
size ; D. sinuata is undulate in side view.

BIBL. Kiitzing, Sp. Alg. 11 ; Smith, Br.
Diat. ii. 19 ; Rabenhorst, Fl. Alg. i. 114.

DEPA'RIA, Hook.— A genus of Dick-
soniaeous Ferns, with stalked indusia, shaped
like ancient flat goblets (fig. 166, p. 242).
Five very rare tropical species.

BEBL. Hooker, Syn. 56.

DEPA'ZEA, Fries. See SPH.EBIA.

DEPOSITS, URINARY. See URINE.

DERMALEI'CHUS, Koch=ANALGES
(Murray, JEcon. Ent. 327).

DERMANYS'SUS, Duges.— A genus of
Arachnida, of the order Acarina, and family
Gamasea.

Char. Body mostly soft; palpi, the fifth

B

DERMANYSSUS.

[ 242 ]

DESMIDIACE^.

Fig. 166.

Deparia prolifera.

Sorus enclosed in the stalked indusium.
Magnified 25 diameters.

(last) joint smallest ; labium acute ; mandi-
bles of the male chelate, external claw very
long ; of the female, ensiform ; anterior legs
longest ; coxae approximate.

D. avium (PI. e.^fig. 24). Found in the
cages of tame singing birds and upon poul-
try. Body ovate-oblong, depressed, slightly
broader and sometimes emarginate pos-
teriorly. The sixth joint of the legs (c) is
the longest. Mouth forming a kind of
moveable head attached to the under part
of the anterior margin of the body ; it con-
sists of: — 1, a triangular labium, pointed in
front, and with two palpi (fig. 24 a*), the
second joint largest, the fifth smallest and
accompanied by a large but short, moveable,
external seta ; and, 3, the two mandibles
(b, of female ; «t of male). Red or reddish
brown.

This species sometimes infests human
beings, producing a skin-disease, being de-
rived from fowls.

D. vespertilionis. Found upon the mouse-
coloured bat ( V. vnurinus). Rostrum nearly
as long as the palpi, broad or oval at the
base, narrowed in front, cleft longitudinally
above, and containing the two long and
slender mandibles.

D. pipistrelli. On the common bat ( V.
pipistrellus).

D. hirundinis. In the nest of the swal-
low.

D. gallinee. On the common fowl.

D. Nitzsckii. In the nostrils of the goat-
sucker (Caprimulffus).

Other species are found on the noctule
bat ( V. noctuld), the merlin, the turkey, the
snail, the mouse, serpents, &c. ; and two on
the paeony and the convolvulus.

BIB:L. I)ng&, Ann. Sc. Nat. 2 se"r. ii. 19 ;

Gervais, Walckenaer's Arach. iii. 222 ; Busk,
Mic. Jn. 1842, ii. 65 ; Kolenati, Sits. Ak.
Wien, 1859, 172 ; Murray, EC. Ent. 169 ;
Me-gnin, Paras. 1880, 115.

DERMATIS'CUM, Nyl.— A genus of
Lichens, tribe Lecanorei, formed to con-
tain Endocarpon Thunbergii, a native of the
Cape of Good Hope.

BIBL. Nylander, Enum. Gen. 116.

DERM ATODEC'TES = SARCOPTES.

DERMES'TES, Linn.— A genus of Der-
mestidae.

DERMES'TEm— A family of Coleo-
pterous Insects.

The larvae of these insects, which are
often minute, create great ravages amongst
dried skins, furs, &c. ; they also feed upon
feathers, bacon, books, paper, insects in
cabinets, mummies, &c. They are particu-
larly interesting to the microscopist, on ac-
count of the peculiar and beautiful structure
of certain of the hairs (PI. 1. fig. 1, a, 6)
existing unon their bodies.

The hairs form three distinct tufts on
each side of the hinder segments of the
bodies of the larvae. The ordinary finely
spinous hairs on the rest of the body are
shown in c.

Although these hairs are generally called
the hairs of Dermestes, it so happens that
this genus is almost the only one in the
species of which the hairs do not exist.

British gen. : Anthrenus, Attagenus, Me-
gatoma, Tiresias, Dermestes, and Trinodes.

BLBL. Westwood, Introd. i. j Curtis, Br.
Insects, 682 ; Stephens, Manual, 142.

DESMAREL'LA, Kent.— A genus of
Infusoria.

Char. Free, united laterally into rows ;
flagellum single, terminal, encircled at the
base by a collar. 2 species, 1 in fresh, the
the other in salt water ; length of bodies
*oVo". (Kent, Inf. 341.)

DESMARES'TIA, Lamx.— A genus of
Sporochnaceae (Fucoid Algae), consisting of
olive or brownish seaweeds, with repeatedly
pinnate, feathery fronds, from one to several
feet long, growing chiefly between tide-
marks or in deep water. The characters of
the reproductive structures have not yet been
made out, as the species rarely fruit on our
coast, although the plants are common.

BIBL. Harvey, Mar. Alg. 23, pi. 5D;
Phyc. Brit. 49, 115; Greville. Alg. Brit.
pi. 5. figs. 1 to 6.

DESMIDIA'CE^E (PI. 14).— A family of
Conferyoid Algae, consisting entirely of mi-
croscopic flexible organisms inhabiting fresh

DESMIDIAOE^E.

243 ]

DESMIDIACE^E.

water, scarcely a specimen of which can be
found that does not contain some of them.
They occur in greatest abundance in clear
pools in open exposed situations, the larger
species being generally found nearest the
bottom. Sometimes they adhere in large
numbers to aquatic plants, forming green
films investing them ; at others they rest as
a thick coating at the bottom of the water,
or lie intermingled with Confervas, &c.

They are most striking objects under the
microscope, from the peculiarity, beauty,
and variety of their forms, their colour, and
their external markings and appendages ;
that which is most distinctive in their ap-
pearance is the bilateral symmetry, indica-
tive of the tendency to divide transversely
into two valves or segments. Each frustule
is in reality a single cell, as is shown by the
fact that the entire contents escape when an
orifice is made ; but in the generality of
the forms, a constriction, or more or less
deep notch, or a kind of suture exists in the
middle of the external cellulose coat. In a
few instances, such as Scenedesmus, the sym-
metrical form is absent ; in Pediastntm
(PI. 14. figs. 48, 49) it is only indicated by
a notch on the outer side ; but a graduated
series majr be formed, from those genera in
which this character is inconspicuous, to
those in which it is fully developed. Thus
in Closterium (figs. 40 to 45) and some spe-
cies of Penium, there is no constriction ; in
Tetmemorus (fig. 33), some Cosmaria (fig.
22), and Hyalotheca (fig. 1], it is quite evi-
dent, although but slight ; in Didymoprium
and Desmidium (fig. 7), it is denoted by a
notch at each angle ; while in Spharozosma,
Micrasterias (fig. 13), and some other
genera, the constriction is very deep, the
connecting portion forming a mere isthmus
between the segments, which appear like
distinct cells.

The cells frequently exhibit external
warty or spinous processes (PI. 14. fig. 23),
and the cellulose coat (coloured blue by
means of iodine and sulphuric acid) presents
minute markings which, unlike those on the
siliceous envelope of the Diatomacese, are
always elevations. The cells are surrounded
by a more or less perfect and distinct
sheath, of gelatinous consistence, and very
transparent. In Hyalotheca, Didymoprium,
Sphcerozosma, &c., this is very well defined
(PI. 14. figs. 1 to 6) ; but in other genera it
is more attenuated, and the fact of its
existence can only be discovered by its
preventing the contact of the cells. The

sheath of Hyalotheca often presents delicate
dark striae, which, if the gelatinous sheath is
not clearly seen, look like rigid cilia standing
upon the surface of the cell- wall ; these
appear to be either fissures in the gelatinous
sheath, connected with the breaking up of
the filamentous groups into single cells, or
they are referable to a fibrous disintegration
of the gelatinous sheaths, such as occurs in
many OSCILLATOBIACEJE.

The contents of the cells of the Desrni-
diaceae appear to resemble those of the green
Confervoids generally, in consisting of a
mass of protoplasm coloured green by chlo-
rophyll, and being entirely enclosed in a pri-
mordial utricle, which does not appear to be
adherent to the cellulose coat in mature
specimens. The contents of the cells con-
tain minute starch-granules as in the other
Confervoids, in the full-grown condition,
and in the zygospores.

It was stated some years ago by Focke,
that the internal surface of the outer coat
of Closterium is ciliated ; and Osborne has
declared that the membrane of the endo-
chrome (primordial utricle) is ciliated both
on its inner and outer surface. These state-
ments are erroneous, as is shown under
CLOSTEBIUM.

The Desmidiaceae, at all events many of
them, have the power of fixing themselves
to external objects, and possess a feeble
power of locomotion, which is not produced
by the aid of cilia, and cannot be explained,
unless on the principles which have been
assumed to account for the same pheno-
menon in the DIATOMACESE. It enables
the Desmidiaceee, when mixed with mud,
to make their way to the surface ; and they
will be found to travel and fix themselves
to that side of a glass vessel next the light.
In some instances, also, they retire beneath
the surface of the mud of pools &c. before
this dries up.

The Desmidiaceae, like other green plants,
evolve oxygen when exposed to the sun's
light.

The reproduction of this family exhibits
a number of very interesting and varied
phenomena. Four modes have been ob-
served; and some points connected with
the subject still remain to be cleared up,

The simplest kind of reproduction is by
cell-division, where each frustule divides
transversely into two. The manner in
which this takes place differs to some ex-
tent in its details in the various genera,
according to the form. Thus in Closterium

DESMIDIACE^E.

[ 244 ]

DESMIDIACE^.

the parent-cell acquires a constricted ap-
pearance in the middle, probably not by
actual constriction, but by the two halves
retreating from each other, while a new
hour-glass-shaped prolongation of the mem-
brane is formed in the middle. It appears
probable also that the primordial utricle
first becomes constricted, since specimens
are met with in which this appears divided
into two portions in the line of the division.
The constriction of the outer cell-wall at
length becomes complete the halves sepa-
rate and the truncate new end of each then
grows out so as to restore the symmetry of
the new frustule. In such forms as Desmi-
dium, Didymoprium, &c., the division takes
place in a manner apparently resembling
that occurring in the filamentous Confervas.
Here there is no necessity for the subsequent
restoration of symmetry, as in Closterium. In
those forms where pairs of globular or ellip-
tical or angular lobes are united by a narrow
neck (bipartite forms), the process of divi-
sion is very curious, and displays itself very
clearly. To produce two new symmetrical
frustules out of one, it is evident that two
new half-frustules must be formed, as in
Closterium j but in the present cases the
foundations of the new halves are laid, and
their development often far advanced, before
the division of the parent is completed.
The central region of the isthmus expands
and displays two globular enlargements,
separated from each other, and from each
half of the parent, by a neck. These two
enlargements are the rudiments of the new
'half-frustules;' and they increase in size
(PL 14. fig. 11), gradually pushing the halves
of the parent-cell apart, until they form two
complete half-frustules, back to back, con-
nected by a short neck, at which point they
are sooner or later detached from one an-
other. In Sphcerozosma the cells thus pro-
duced remain connected in rows in a gela-
tinous sheath ; and this mode of division is
well illustrated by the cells in various stages
sometimes seen in such filaments ; in Euas-
trum, Cosmarium,Staurastrum, &c.,the new
cells separate, the old half-frustules taking
away each their new halves as new bi-
partite individuals. The membrane of the
nascent halves is very delicate, and at first
devoid of the characteristic markings and
processes j and it often happens that these
are not completely formed before the division
is complete. Archer has described some
monstrosities of these new halves.

A second mode of reproduction has been

described by Caspary and Braun, in Pedi-
astrum. The contents of the parent-cells
become retracted from their walls, and
the whole transformed into a number of
active ciliated zoospores, which are dis-
charged within a delicate sac from the
parent, and after some time come to rest
and arrange themselves within this sac (PI.
10. fig. 11) into a colony having the regular
pattern of the species, each zoospore be-
coming one of the notched frustules of the
group (see PEDIASTRUM) .

A third process, analogous to this, has
been observed by Pringsheini in the genus
Calash-urn, likewise composed of grouped
families : here the contents of each cell are
divided into a number of portions, as if for
the formation of zoospores (still zoospores),
but no motion takes place; they acquire
cellulose coats, arrange themselves within
the parent according to the typical pattern ;
and then the wall of the parent-cell splits
and peels off; leaving them as the founda-
tion of a new group. Connected with this,
is a phenomenon which has been observed
and figured in Closterium, by Focke, where
the entire green contents were only retracted
from the walls, and broken up into a number
of green encysted globules (PL 10. fig. 3B),
closely resembling the thick- walled resting-
spores or winter-spores of Volvox (PI. 7.
figs. 26, 34), &c.

The fourth mode of reproduction is by
what is called Conjugation, where two cells
of a single filament, or of two separate fila-
ments, contract an organic union, their cavi-
ties becoming continuous, and their contents
becoming blended to form the substance of
a zygospore. These are at first cellulose
vesicles filled with green and granular con-
tents, their starch being converted into
fat ; by degrees they become brown or red,
and the coats become thickened. In some
genera the coats remain smooth : in others
they acquire a granular, tuberculated or
even a spinous surface (PI. 14. fig. 12),
these spines being either simple or forked.
Bodies exactly resembling these are found
fossil in flint, and are regarded as of the
same nature by Ralfs and others ; Ehrenberg
described them as species of XANTHIDIUM.
In germination, the contents of the
zygospore escape as a thin- walled vesicle,
and become divided into a more or less
numerous brood of secondary cells, resembling
those of the parents (PI. 10. fig. 3 Ad.).

The Desmidiacese may be collected in the
same manner as is recommended for the

DESMIDIACE^E,

C 245 ]

DESMIDIACE^E.

DIATOMACE^E. Their preservation is a
difficult matter, as almost all the preser-
vative liquids alter them more or less.
Those producing the smallest amount of
change are Thwaites's liquid, Ralf s's liquid,
or simple camphor-water ; but these liquids
always escape in time from the cells. A
few, for example Pediastrum,axQ unchanged
by concentrated solution of chloride of cal-
cium very gradually added, except that the
colour becomes rather paler, or solution of
acetate of potash ; moreover the cell-mem-
brane, upon the forms of which the
characters mainly depend, remains unal-
tered in all the kinds when kept in these
solutions. Many prefer glycerine, which is
really the best preservative medium ; in
some cases glycerine-jelly is used.
See PRESERVATION.

Analysis of the Tribes and Genera. (PI. 14.)

I. CLOSTERIE^:. Cells single, elongated,
never spinous, frequently not constricted
in the middle (sporangia smooth).
Closterium. Cell crescent-shaped or arcu-
ate, or much attenuated at the ends, not con-
stricted in the middle (figs. 40-45, 57, 58).

Penium. Cell straight, not or very
slightly constricted in the middle, rounded
at the ends (fig. 36).

Tetmemorus. Cell straight, constricted
i the middle, notched at the ends (figs. 33,
34).

Docidium. Cell straight, constricted in
the middle, truncate at the ends (figs. 38, 39).

Spbrot&nia. Cell straight, not constricted;
endochrome spiral (fig. 59).

II. COSMARIE^J. Cells single, distinctly
constricted in the middle j segments sel-
dom longer than broad (sporangia spinous
or tuberculated).

Micrasterias. Lobes of the segments in-
cised or bidentate (fig. 13).

Euastrum. Segments sinuated, generally
notched at the ends, and with inflated pro-
tuberances (figs. 14 to 17).

Cosmarium. Segments neither notched
nor sinuated, end view elliptic, circular, or
cruciform (figs. 18 to 22).

Xanthidium. Segments compressed,
entire, spinous (figs. 23 to 25).

Arthrodesmus. Segments compressed,
each with only two spines (fig. 27).

Staurastrum. End view angular, radiate,
or with elongated processes (figs. 26, 28-32,
and 56).

HI. DESMIDIE^. Cells united into an

elongated jointed filament (sporangia

spherical, smooth).

Genicularia. Filament cylindrical, smooth ;
endochrome spiral (PI. 51. fig. 36).

Gonatozygon. Filament cylindrical or
fusiform, smooth ; endochrome longitudinal,
wavy (PI. 51. fig. 37).

Hyalotheca. Filament cylindrical, cells
crenate (PI. 14. figs. 1, 2).

Didymoprium. Filament cylindrical or
subcylindrical ; cells with two opposite bi-
dentate projections (figs. 5, 6).

Desmidium. Filament triangular or qua-
drangular; cells with two opposite bidentate
projections (figs. 7, 8).

Aptogonum. Filament triangular or plane,
with foramina between the joints (figs. 52,
55).

Sphcerozosma. Filament plane, margins
deeply incised or sinuated (figs. 9, 10).

IV. ANKISTRODESMLE. Cells elongated, en-
tire, small, grouped in faggot-like bundles.
Ankistrodesmus (fig. 47).

V. PEDIASTRE^:. Cells grouped in the
form of a disk or star, or placed side by
side in one or two short rows.
Pediastrum. Cells forming a disk or star,

marginal cells bidentate (fig. 48).

Monactinus. Cells as in Pediastrum, but
marginal cells unidentate (PI. 36. fig. 28).

Scenedesmus. Cells placed side by side
in one or two rows (figs. 50, 51, 53, 54).

Ccelastrum. Cells forming a hollow sphere
(PI. 3. fig. 8).

Three interesting genera are described
and figured by Wallich from Lower Ben-
gal (Leuronema, Onychonema, and Strep-
tonemd).

Tetrachastrum, Archei=Micrasterias,-pt. ;
Triploceras— Docidium, pt. ; Leptocystinema,
Arch.= Gonatozygon, De Bary; Spondylo-
sium= Sphcerozosma, pt.

Rabenhorst places Cosmodadium among
the PalmellaceaB.

BIBL. Ralfs, Br. Desmid. ; Ehrenberg,
Inf.-, Pritchard, Infus.-, Hassall, Algce-
Nageli, Einzett. Alg. 1849; Braun, Vermng
(Ray Soc. 1853); Focke, Phijs. Studien,
1848 ; Caspary, Bot. Zeit. viii. 786, 1850 •
Pringsheim, Flora, 1852, 486 ; Hofmeister,
Ann. N. H. 3 ser. i. 1 ; Carter, ibid. 2 ser.
xvii. ; Thomas, Mic. Tr. 3 ser. ; Bailey
Smiths. Contr. 1854; Rabenhorst, Fl Alg
m. 102 ; Wallich, Ann. N. H. I860. v. 184,
273; Archer, Qu. M. Jn. 1860, viii. 85,
215, 235 ; BrSbisson, Liste, 1856, 2 plates ;

DESMIDIUM,

246 ]

DIAPTOMUS,

Sachs, Sot. 262; Notaris, Desmidiacee
Italiche, 1867; Delaporte, Desm. siibatp.
1877 (23 pis.).

DESMID'IUM, Ag.— A genus of Desmi-
diaceae.

Char. Cells united into a brittle, regu-
larly twisted, triangular or quadrangular
filament, and two-toothed at the angles.

The filaments exhibit one or two dark,
oblique, wavy lines, arising from their being
twisted. In the side view of the cells, the en-
dochrome exhibits thick,fre<juently cleft rays,
corresponding in number with the angles.

D. Swartzii (PI. 14. fig. 7; fig. 8, side
view of separate cell). Filament triangular.
Length of joint 1-2000 to 1-1660" ; breadth
of filament 1-630". Not uncommon. Spo-
rangia round or oblong.

D. quadrangulatum. Filaments quadran-
gular. Length of joint 1-2400"; breadth
of filament 1-600 to 1-450".

BIBL. Ralfs, Br. Desmid. 60; Kiitzing,
Sp. Alg. 190.

DESMOGONIUM, Ehr.— A genus of
DiatomaceaB.

Char. Frustules those of Synedra united
into tablets, which are coherent by the angles.

D. Kutzingii. Submarine marshes; Ger-
many.

D. Gujanense. Found in Asia, Africa,
and America.

BIBL. Ehrenberg, Mikrog. ; Rabenhorst,
Flor. Alg. i. 142.

DEUTZ'IA, Thunberg.— A genus of Phi-
ladelphaceee (Dicotyledonous Plants) re-
markable for the stellate hairs upon their
foliage (PI. 28. fig. 26*), and the reticulated
membrane covering the seeds; both of which
structures form in-
teresting microsco- Fig. 167.
pic objects. See
HAIRS and SEEDS.

DIACAL'PE,
Bl. — A genus of
Cyatheae(Polypodi-
aceous Ferns), with
globular indusia,
splitting open at
thetop(fig,167),and
containing spo-
ranges inserted on a
punctiform recep-
tacle rising from
the middle of the
vein. Herbaceous ;
leaves tripinnate,
membranous. Native of Java, &c.

BIBL. Hooker, Syn. 45.

Diaealpe asplenioides.

Part of a pinnule with sori.

Magnified 10 diams.

DIACH^E'A,Fries.— Age- Fig. 168.
nus of Myxomycetes, consist-
ing of perishable little plants,
growing over either living or
dead plants, with an elongated
membranous peridium, which
falls oft' like a cap, and displays
a white reticulated capillitium
furnished with a floccose cen-
tral column, with interspersed
blackish-red spores.

Diachcea diners from Stemo-
nitis in the peridium, the colu-
mella, and the habit of growth.

D. elegans, Fr. (Stemonitis,
Trentep.), the only species,
has been found in England,
upon the living leaves of the
Lily of the Valley &c. (fig.
168).

BIBL. Fries, Syst. Mycol.
iii. 155; Berk. Ann. N. H. i.

257 ; Corda, Ic. Fung. V. pi. 3. Diacheea elegans;
fig. 38. Magn. 25 diama.

DIADES'MIS, Kiitz.— A genus of Dia-
tomaceaa (Cohort Naviculeae).

Char. Frustules navicular, closely united
into elongated biconvex filaments; valves
with a median and terminal nodules.
Freshwater and marine.

The markings have not been satisfactorily
investigated.

D. confervacea (PI. 16. fig. 27). Breadth
of frustules (in front view) about half the
length; valves lanceolate, acuminate and
acute at the ends; length of frustules
1-960".

Eight species, some fossil.

BIBL. Kiitzing, Sp. Alg. 95; Rabenhorst,
Flor. Alg. i. 259.

DIAMOND-BEETLE. See CUBCULIO.

DIAP'TOMUS, Westw.— A genus of
Entomostraca, of the order Copepoda, and
family Diaptomidae.

Char. Head distinct from thorax ; inferior
antennae two-branched; thorax and abdo-
men each of five segments; foot-jaws un-
branched ; legs five pairs, the first pair with
two branches, one three- the other two-
jointed; three succeeding pairs with each
branch three-jointed; external ovary single,
large, lying across the abdomen.

D. castor (PI. 20. fig. 38). Found in ponds
and slowly-running water; common in spring
and autumn. Length about 1-8".

BIBL. Westwood, Entom. Text-book-,
Baird, Br. Entom ; M.-Edwards, Crust, iii.
427.

BIAS.

[ 247 ]

DIATOMACE^B.

BIAS, Lillj. — A genus of Copepoda (En-
tomostraca).

D. longiremis. Cumberland.

BIBL. Brady, Copepoda (Ray Soc.) i. 50.

DIASTO'PORA, Lamouroux.— A genus
of Infundibulate Polyzoa, of the suborder
Cyclostomata, and family Tubuliporidse.

Distinguished by the incrusting, unde-
fined or foliaceous zoary ; and the alternate,
tubular, horizontal, immersed cells, with a
raised circular orifice.

D. obelia. Crust thin, closely adnate.
Three other species,

BIBL. Johnston, Br. Zooph. 276 ; Gosse,
Mar. Zool. ii. 8 ; Hincks, Polyzoa, 457.

DIATOM A, Dec.— A genus of Diato-
macese (Cohort Fragilariae).

Char. Frustules (in front view) linear,
sometimes cuneate ; at first united into flat
filaments, afterwards partly separating so
as to remain connected by the generally
alternate angles only, and thus forming a
zigzag chain.

Filaments either free or fixed by a stipes.
Frustules prismatic, without vittae 5 valves
with transverse continuous striae (costse)
and intermediate finer striae, not always
visible by direct light; ends of the stride
extending into the front view.

Five British species :

D. vulgare (PL 16. fig. 26 : «, side view ;
b, front view). Fixed by an inconspicuous
stipes; frustules rectangular, oblong ; valves
elliptical, contracted and obtuse at the ends ;
striae evident; length of frustules 1-430".
Freshwater.

D. elongatum. Frustules very slender,
slightly attenuated towards the middle ;
valves linear, evidently striated, tumid
and rounded at the ends; length 1-280".
Freshwater.

D. grande. Valves linear, constricted near
the rounded ends ; costae evident. Fresh-
water.

D. hyalinum. Filament of numerous
frustules; valves linear-elliptical, ends sub-
acute, striae obscure. Marine.

D. minimum. Frustules two or three ;
valves elliptical, ends rounded; striae ob-
scure. Marine.

BIBL. Ralfs, Ann. N. H. 1843, xi. 449;
Kiitzing, Sac. fy Sp. Alg. 16; Smith, Br.
Diat. ii. 38 ; Rabenhorst, Fl. Alg. i.

DIATOMA'CE^E.— A family of Confer-
void Algae, of very peculiar character, con-
sisting of microscopic brittle organisms,
found in almost all fresh, brackish, or salt
water; sometimes forming a uniform yel-

lowish-brown layer on the bottom of the
water, at others adhering to various water-
plants, decaying stems, stones, &c., or scat-
tered between the filaments of Conferoe
and marine Algae &c. They also occur
among Mosses, Oscillatorice, and on damp
ground.

The individual cells of the Diatomaceae
are called frustules or testules, and are fur-
nished with a coat of silica (Cytioderm).
This consists of two usually symmetrical
portions or valves comparable to those of a
bivalve shell, which are in contact at their
margins with an intermediate piece (the
hoop), variable in breadth, according to age
&c. When this is very narrow, it forms a
mere junction line, and is called the line of
suture j and that aspect of the frustules in
which this is turned towards the observer
forms the front or front view : primary side,
Kiitzing; secondary side, Rabenh. (PI. 15.
fig. 7 ; PI. 16. figs. 9 a, 30 b). That aspect
of the frustules in which the surface of the
valves is turned towards the observer, forms
the side or side-view of the frustules :
secondary side ; Kiitzing, primary side, Ra-
beuh. (PL 15. fig. 6; PI. 16. fig. 30 a).

The separate valves are of various forms :
circular, oblong, elliptical, linear, saddle-
shaped, boat-shaped (navicular), undulate,
sigmoid, &c, (Pis. 15, 16, 17); and their
surfaces exhibit various more or less delicate
sculpturings and markings, in the form of
bands, lines either parallel, radiate, or cross-
ing each other, and dots, or a cellular
(areolate) appearance.

These markings are in general not well
seen, and in some cases cannot be seen at
all, until the valves have been properly pre-
pared. They are of special interest, not
only on account of their extremely beautiful
delicacy and symmetry, but because they
are used as tests for the quality of the
object-glasses in regard to angular aper-
ture. The nature of the markings is de-
scribed under the individual genera; and
the modes of viewing them will be spoken
of further on.

In some the hoop is a simple filament, so
curved or bent as to assume the form of
the section of the frustules, or the edges of
the valves (PL 15. fig. 11). In others, it is
broad, and marked like the surfaces of the
valves (PL 17. fig. 2 a). In others, again,
the hoops are numerous, flat, and arranged
like the leaves of a book, each with a round
or oval aperture in the middle, so that the
cavity of the frustules is divided into loculi j

DIATOMACEAE.

[ 248 ]

DIATOMACEAE.

these frustules we shall distinguish as com-
pound (PL 18. fig. 69).

During the process of multiplication by
division, which is almost always going on,
the annular siliceous, narrower or broader
band, or hoop, undergoes an increase of
width, and the two valves are removed
some distance apart (PI. 15. figs. 7, 45;
PI. 16. fig. 1). Sometimes it consists of
two pieces, one overlapping the other.
Some of the valves are furnished with pro-
cesses, called cornua or tubuli (PL 16. fig.
30 b) ; the surfaces of others are undulate,
producing the appearance of dark curved
or wavy lines or bands (PL 16. figs. 22, 23,
24); sometimes curiously arranged lines,
(vittae) indicate either imperfect internal
septa, the internal margins of the flattened
hoops, or certain inflections of the margins
of the valves (PL 1. figs. 14, 15 ; PL 17.
figs. 17, 18).

In the young state of these organisms,
the endochrome or cytioplasm is uniformly
distributed; but after a certain time, it
becomes accumulated into various, usually
very regular and often elegant forms, and
minute granular globules are formed, trans-
parent vesicles become visible, drops of oil,
and vesicles filled with granules, which at
first are motionless, but afterwards move
about as in the swarming motion of the
Algae. Frequently a considerable nucleus-
like body is present in the middle of the frus-
tule (PL 15. %. 33 a). As we have seen it,
delicate processes were visible arising from it.

The frustules of the Diatomaceae are
sometimes surrounded by a transparent ge-
latinous sheath, frequently of great delicacy,
or contained in gelatinous simple or branched
tubes ; in some genera they are attached by
a stipes or stalk to water-plants &c.

Those Diatomaceae which are not fixed
by a stipes, and especially such as are linear
or spindle-shaped, are capable of sponta-
neous motion ; they may be constantly seen
slowly moving across the field, or now and
then starting somewhat suddenly forwards,
moving mostly in the direction of their
length, sometimes receding, sometimes per-
forming a rotatory movement on their axis.
Those which are contained in numbers in
gelatinous tubes, like Encyonema (PL 19.
fig. 10), are capable of moving backwards
and forwards in these; and Thwaites de-
scribed a curious movement of the frustules
of Bacillaria paradoxa, where the frustules,
united in a band, slid backwards and for-
wards over one another.

The cause of this motion is undetermined.
It has been supposed to be produced by the
endosmotic changes connected with the
nutrition of the organisms ; but this is very
improbable, otherwise it would be met with
frequently in other minute . unicellular or-
ganisms; moreover, the diffusion -move-
ments are far too slow and gentle to explain
them. No true vibratile cilia have oeen
detected upon the Diatomaceae, although
Thwaites imagined, from the appearance of
currents in the water, that they exist on
Bacittaria. Some are not unfrequently
found bearing tufts of or fringed with rigid
cilia, like those often seen at the ends of
the filaments of Oscillatorice ; these would
seem to be formed like the fringes met with
in the Desmidiaceae, by a modification of
the gelatinous envelope; they never exhibit
motion.

It has more recently been supposed to
arise from the action of a delicate layer of
protoplasm investing the frustules, or pro-
truding through chinks between the valves
of the frustules at the suture. (H. L. Smith,
Jn. Mic. Soc. i. 1878-79.)

In placing the Diatomaceae among plants,
we assume an agreement between the frus-
tule of a Diatomacean and an individual cell
of any undoubted vegetable, such as Proto-
coccus ; and between the series of frustules
such as we find in Fragilaria (PL 16. fig. 33),
or Melosira (PL 17. fig. 5 a), and the cellu-
lar filament of a Conferva or a Zygnema.
This agreement does undoubtedly exist ; and
the siliceous shell is really only a result of
the incrustation or permeation by silica of a
true vegetable cell-membrane, just in the
same way as takes place in the epidermis
of Equisetum. It is not yet ascertained in
either case whether the silica is outside or
in the substance of the cell-membrane;
certainly it is not inside, as that would be
incompatible with the known phenomena of
division. It may be removed by hydrofluoric
acid, leaving the basement membrane in
situ ; but this proves nothing. The proba-
bilities are that the substance of the mem-
brane is imbued with it.

In regard to the cell-contents of the Dia-
tomaceae, there exists a layer of protoplasm
forming a primordial utricle, inside the cell-
membrane, and enclosing the rest of the
contents. In the coloured substance con-
stituting the mass of the endochrome the
chlorophyll is obscured by a yellow colour-
ing-matter, diatomine or phycoxanthine ; it
takes a green or greenish-blue tint with

DIATOMACE.E.

[ 249 ]

DIATOMACE^E,

sulphuric acid, and also often by drying ;
and H. L. Smith has shown that it exhibits
the spectroscopic reactions of chlorophyll.
Oil-globules, soluble in ether, are also found,
sometimes of large size, in particular stages
of growth, probably representing here the
starch-grains found in other Confervoids,
or indeed the oil which occurs in them and
other plants in seasons of rest. No starch
has been detected in this family. A trans-
parent rounded nuclear body is often ob-
served in the centre of the contents.
Schmidt found in Frusculia salina, after
removing the oil by ether and the proto-
plasm by potash, a substance identical in
composition with the cellulose of Lichens.
This was probably derived from the organic
matter of the silicified membranes of the
frustules.

The ordinary mode of increase of the cells
of the Diatomaceae is, like that of all other
vegetable cells, a process of division. In
Melosira, Isthmia, &c. this bears a close re-
semblance to the process which occurs in
Spiroyyra ; and it is only a modified form of
the same process that is found in the free
Diatomaceae. It may be briefly described
thus : — the primordial utricle, enclosing the
contents, divides into two portions, which
separate from one another in a plane parallel
with the sides of the individual frustules ;
the two valves of the parent-cell gradually
separate from one another, remaining con-
nected by the simultaneous gradual widen-
ing of the hoop. In the space thus afforded,
the two segments of contents secrete each
a new layer of very delicate, easily crum-
pled membrane without markings, which
ultimately becomes silicified over the sur-
faces, constituting two new half-frustules,
back to back, corresponding to and con-
joined with the two half-frustules of the
parent to form two new individuals. The
markings on the new valves are sometimes
different from those upon the parent. The
history and ultimate fate of the hoop seems
to be variable. Sometimes it becomes
solidly silicified, but not much expanded in
breadth, and falls off when the two frus-
tules are complete, allowing them to sepa-
rate; this is the case in Pleurosigma, and
probably in all the allied forms; these
hoops are often to be found in large num-
bers in the settlings of water in which
Diatomaceae have been kept a long time.
Perhaps the most remarkable development
of the silicified hoop occurs in Biddulphia
(PI. 19. fig. 9), Isthmia, and similar forms :

the new half-frustules formed inside the
hoop of these genera slip out from it like
the inner tubes from the outer case of a
telescope. In Melosira (PL 10. fig. 8) the
hoops appear to keep the new frustules
united together for some time ; and here
there is no overlapping.

The development of the stipes to which
the frustules of many genera are attached,
is obscure; Cox suggests that in Isth-
mia, a separate internal cell exists, near
the point at which the frustule is attached,
having the office of secreting the gelatinous
substance of the stipes.

The only mode of reproduction, besides
the division, known certainlv to exist in the
Diatomaceae, is that in which conjugation
takes place. This has been observed in a
number of genera, and presents considerable
variation in its details. In Fragilaria
(PI. 10. fig. 4) and SurireUa (PL 10. fig. 5)
the conjugation takes place between two free
frustules lying near together, each of which
opens at the suture and extrudes its con-
tents in a mass (probably enclosed in the
primordial utricle) ; the masses of contents
coalesce, the whole meanwhile becoming
involved in a mass of gelatinous substance.
After a while, the body resulting from the
conjugation is seen to assume the form of a
frustule, of larger size than the parents,
which Thwaites, the discoverer, called a
sporangial frustule. In the majority of
cases, however, as in Eunotia (PL 10. fig. 6),
Gomphonema Cocconema, &c., the conjuga-
tion is double, as is the case in Closterium
lineatum (CONJUGATION) ; the contents of
the parent-frustules apparently divide into
two portions (as if for cell-division) before
conjugating; and then there is a collateral
conjugation of the two pairs, two sporan-
gial frustules being the result. In Melosira
(PL 10. fig. 8) and Orthosira (PL 10. fig. 9)
the appearances presented seem to indicate
that the conjugation takes place between
two segments of a frustule which have
separated as if for ordinary cell-division ;
but, instead of forming new half-frustules,
have coalesced again and secreted a coat
over the entire surface, thus constituting
one new independent sporangial frustule of
larger size. In Achnanthes and Rhabdo-
nema, two sporangial frustules are formed
after the conjugation of the two halves of
one (just-divided) frustule. Probably this
is a case of very early division of the conju-
gation-body. In Melosira (PL 10. fig. 8)
the conjugation-body has been observed to

DIATOMACE^E.

[ 260 ]

DIATOMACE^E.

increase by cell-division, and form a new
filament of far greater diameter than that
to which it owed its birth. The sporangial
frustules of the free forms doubtless increase
by cell-division in the usual way (see CON-
JUGATION).

In some cases the first product of the
conjugated mass is a siliceous sheath, inside
which a new frustule is developed, and
finally set free by dehiscence of the sheath
(see NAVICULA).

A great difficulty meets ua here. The
necessary consequence of the conjugation
just described is, that every species in
which it occurs must be represented by two
forms, one small and the other large, be-
tween which a gap exists, over which we
have at present no means of "

cept by supposing that the two new
formed in cell-division need not always be
equal, and that, by a dwindling away through
a succession of steps of this kind, the pro-
geny of the sporangial frustules may be re-
duced to the original size. The size of the
frustules is said also to vary with the depth
of the sea, in marine species. The effect of
all this seems to have been disregarded in
systematic treatises on the Diatomaceae.
Some of the book-species appear to produce
other book-species by conjugation ; accord-
ing to Focke, Surirella spkndida produces
S, bifrons, a very distinct form ; and it is not
improbable that S. spkndida is produced by
the conjugation of S. Microcora (Focke).
There is great probability, however, that
the observations made by Focke upon the
contents in certain species will lead to the
discovery of another mode of increase —
a reproduction by gonidia, either active
or quiescent, such as occurs in the Desmi-
diaceae and the other Confervoids. Indeed
the contents of the cells of Melosira have
been observed to display a motion like
1 swarming.' Such spores or gonidia dis-
charged from the large ' sporangial ' frus-
tules might reproduce the small form, just
as the young filaments developed from the
zoospores of Chcstophora &c. are very slen-
der compared with those of full-grown fila-
ments. Focke describes and figures appear-
ances in the contents of the frustules of
Pinnularia viridis, Surirella bifrons, and
others, very like what occur occasionally in
the cell-contents of Closterium, namelv en-
cysted globules (PI. 10. fig. 10) resembling
the resting-spores of Volvox and the fila-
mentous Confervas ((EDOGONIUM) j and he
considers that such bodies produced in S.

bifrons may probably reproduce S. Micro-
cora. In some of Thwaites's figures of
conjugating Diatomaceae (PI. 10. fig. 6),
there are appearances which would lead to
the idea that spores were occasionally pro-
duced in this process.

The principal attraction of the Diatoma-
cese to microscopists, however, lies at
present in the structure of the siliceous
coats.

Some remarks upon the method of ren-
dering the markings visible have been made
in the INTRODUCTION, p. xxviii (IttumitM-
tiori) ; and upon the cause of their becoming
visible under proper illumination, in the
article ANGULAR APERTURE. The grounds
for the belief that most the finer markings
are depressions have also been mentioned
(INTRODUCTION, p. xxxix, I.). But the
general view now entertained is, that the
finer markings of the valves are the optical
expression of hemispheres of silica (PL 15.
fig. 46) ; although it is curious, that neither
Schultze nor Abbe agree with this view.
Yet the formation of the various costae,
vittae, and other siliceous structures in the
valves, cannot be referred to any simply
crystalline or crystalloid hemispherical de-
position.

Preparation of the valves, to render them
as distinct as possible, is essential. This
may be effected in two ways : — 1. By inci-
nerating them upon a very thin plate of
mica or platinum foil over the flame of a
spirit-lamp. This is the quickest "method ;
but it has the disadvantages of the valves
often becoming semifused or agglutinated
to each other by the effects of the heat in
the presence of the alkaline salts contained
in all organic matters, especially those which
are of marine origin. 2. Boiling with strong
nitric acid; this is the best method. The
water containing the Diatomaceae is allowed
to settle for twenty-four hours, the superna-
tant liquid poured off, and the deposit dried
in a porcelain dish. Strong nitric acid is
then added, the whole mixed with a feather
or glass brush, and poured into a flask or
test-tube and boiled tor some time, a portion
being removed occasionally with a narrow
dip-tube to determine when the valves are
perfectly clean. When this is the case di-
stilled water is added to the mixture, and
the whole allowed to settle. The super-
natant liquid is then carefully decanted,
more water added, and the mixture again
allowed to settle, poured off, and these ope-
rations repeated until a drop of the liquid

DIATOMACE^E.

[ 251 ]

DIATOMACILE.

containing the valves, when evaporated on a
slide, leaves no film (of calcareous salts) at
the margins of the drop. This is a some-
what tedious process ; but it is essential that
it should be thoroughly carried out. If the
valves be not thoroughly washed, the film
of nitrate of lime remaining upon the slide
will absorb water from the atmosphere, and
the whole will be spoiled.

It has been found advantageous, after the
treatment of the valves with acid and
washing, to shake them up with a mixture
of equal parts of glycerine and water ; they
then suik through the water into the gly-
cerine, the flocculent matter being retained
by the water. Thorough washing and de-
cantation will then remove the glycerine
(Neil). Boiling with a small portion of
yellow soap, after the acid treatment, is
highly recommended (H. L. Smith).

The appearance of the valves thus pre-
pared will vary according to their structure,
and the manner in which they are examined.
In some cases the valves appear colourless,
and the markings perfectly distinct with
the ordinary direct light of the mirror, pro-
vided the power be sufficient (PI. 17. figs.
2, 29 5 PI. 61. fig. 1). In others (PI. 15),
the valves appear coloured when viewed by
the ordinary light. But when the mirror is
brought to one side, and the light is thus
thrown upon the object obliquely, one or
two sets of fine parallel black lines are seen
traversing the valves (PI. 1. figs. 17, 18;
PI. 16. figs. 10, 12, 15, &c.). And when an
object-glass of considerable aperture is used,
with the condenser and central stop exactly
centrical (INTRODUCTION, p. xix), the lines
are replaced entirely or in part by a series of
black dots (PI. 1. fig. 16; PI. 15. figs. 39,40,
&c.); these, under a high eyepiece, have
distinctly angular forms, sometimes appear-
ing regularly hexagonal (PI. 15. fig. 41).
If the condenser and stop be not exactly
centrical, or the surface of the valve be not
flat, the appearance of dark dots will be
replaced by that of a set of brilliant pearls
(PI. 15. fig. 46), which, as we have stated,
many observers consider to represent little
hemispherical elevations on the surface of
the valves ; or the true form of the dark
dots will be replaced by some other ; thus
hexagonal dots may be made to appear tri-
angular, quadrangular, &c., and those dots
which cannot be conceived to be really
hexagonal (PI. 15. fig. 39) may be made
to appear so.
There can be little doubt that the valves

of all the Diatomaceae are furnished with
markings, although in some of them they
have not yet been detected. In the most
difficultly resolvable of those at present
known, lines only can be rendered evident,
although these probably consist of rows of
dots ; these very difficult valves require the
use of an Amici's prism (INTRODUCTION,
p. xxi), Powell's latest modified Gillett's
condenser, the method described in the
INTRODUCTION, p. xxx, with immersion-
lenses, or Wenham's reflex-illuminator
(See also ILLUMINATION).

We have already stated that we believe
the dots to consist of depressions. In re-
viewing the considerations relating to this
point, we may divide the valves into those
which exhibit the dots by ordinary light,
and those which require oblique light and
the use of stops.

In those visible with ordinary light (PI. 17.
fig. 29 ; PL 51. fig. 1, &c.), the valves are
thinner and weaker at the parts occupied by
the dots, so that the line of fracture corre-
sponds to these parts and the depressions, are
distinctly visible at the edges of the curved
portions of the valves (PI. 17. fig. 26). In
those requiring the use of oblique light and
stops, the line of fracture also corresponds
to the rows of dots, provided the light be
equally oblique on all sides ; and the same
appearances are presented by the dots in
both cases, beginning with those in which
they are very large (as in Isthmia), to those
of moderate and small size (as in the species
of Coscinodiscus), down to those in which
they are extremely minute (as in Gyrosigma
&c.). Moreover, analogy affords a strong
confirmatory ground; for the Diatomaceas
form a very natural family : and if the dots
are depressions in some genera, we might
expect them to be so in the others.

The explanation of the manner in which
oblique light renders the dots visible, has
been given under ANGULAR APERTURE.

The method of determining the structure
of the frustules of the Diatoniacece is the
same as that of microscopic bodies in ge-
neral, and has been laid down in the IN-
TRODUCTION, p. xxxviii. The presence or
absence of a gelatinous envelope or a stipes
should first be decided. The general form
of the frustules, both in the front and side
view, is next examined, which should be
done while they are immersed in water,
— the frustules being made to roll over by
gently moving the glass cover with the
point of the mounted needle, the eye being

DIATOMACE.E.

[ 252 ]

DIATOMACE^E.

kept upon the object, and a somewhat low
power used.

The frustules should then be prepared,
and examined when dry as to their mark-
ings. Perhaps these may be visible by
ordinary light ; if not, the mirror should
be turned on one side as much as possible,
to obtain the effects of oblique light. If
lines then become visible, it does not
follow that the valves are marked with
lined structures such as grooves or ridges,
because the shadows of rows of dots may
become extended into lines under oblique
illumination in any direction in which the
dots will form a linear series. This point
must, however, be decided by examination
with the aid of the condenser, stops, &c.

In using very oblique unilateral light,
spurious rows of parallel lines are often
seen, not only upon the valves of the Dia-
tomacese, but upon objects not possessing a
lined structure, as many crystals &c. These
can only be distinguished from those con-
nected with the presence of dots, by their
not being resolvable into dots, their greater
coarseness, and their variability in number
in a given space under different kinds of
illumination.

If the direction of the lines changes with
the variation of the position of the valve to
that of the incident light, it may be pretty
surely predicted that the lines are spurious,
and that the condenser and stops will effect
their resolution into dots.

The prepared valves of the Diatomacese
frequently appear coloured when dry, the
colour vanishing when they are moistened.
This colour arises from iridescence, and
not from the presence of pigment or
other colouring - matter (INTRODUCTION,
p. xxxiv, 3).

Collection. In collecting the Diatpmaceae,
a number of phials (1- to 2-oz.), with wide
mouths and furnished with corks, must be
provided, in which they may be brought
home. The mouth of the bottle being closed
with the thumb and brought as closely as
possible to masses of them in the water,
on removing the thumb, the water will
enter and carry the Diatomacese with it
into the bottle. A spoon is frequently of
use in removing layers of them from the
bottom of the water, or from pieces of
woodwork &c. immersed in the water.
Many of them are entangled in the meshes
of Confervae and other Algae, or on the
submersed stems of the higher plants; these,
if fixed to the stems, can only be removed

with them ; if, however, the masses of
Diatomacea& are merely entangled in the
meshes of their stems, they may be detached
and collected in the " ring-net " (INTRO-
DUCTION, p. xxviii), and the pieces of muslin
placed in the bottles. A stick with a loop
of string at the end, is often useful in pro-
curing those which would be otherwise
beyond reach : the neck of the bottle being
engaged in the loop, and the mouth kept
downwards when immersed in the water
until opposite and close to the masses of
Diatomaceae, it is then inclined upwards
and filled. On exposing the bottles to the
light for some hours, the Diatomaceae will
collect on the surface of the mud or other
matters, and can then be removed with a
dipping-tube. It is often difficult to free
them from minute particles of sand ; this
may, however, generally be done by dif-
fusing the deposit through distilled water,
allowing the mixture to stand for a short
time, and then pouring off the uppermost
portions; the sand being the heaviest, will
subside first. The deep-sea species may be
obtained by dredging, or by treating the
alimentary canal of fishes, mollusca, &c.
with strong nitric acid as above directed.

The Diatomaceee are often found fossil ;
occurring in vast numbers in freshwater
and marine geological deposits, forming
hills, rocks, and various strata ; also in peat-
beds, fossil polishing powders, as tripoli,
berg-mehl, &c. The deposits from Fran-
zenbad, Bilin, Richmond (U.S.). San Fiore
(Tuscany), Bermuda, Lough Morne (Ire-
land), Peruvian guano, &c., are well known
as containing many of the most beautiful
species, and are sold by the dealers in mi-
croscopic objects and apparatus.

The masses may sometimes be disinte-
grated by placing lumps in a test-tube,
covering them with Liquor Potasses, boiling
for a short time until the whole breaks up
into a mud, and then instantly pouring it
into a quantity of distilled water, and well
washing.

Preservation. The Diatomaceas may be
preserved either in the dry state, immersed
m balsam, in water, or dilute spirit one to
six (PRESERVATION). For exhibiting the
delicate markings, they should be mounted
in the dry state, placed upon and covered
by the thinnest glass which can be obtained.

The mounted sable-hair or bristle will be
essential in isolating single valves (INTRO-
DUCTION, p. xxvi) for mounting.

With regard to the systematic arrange-

DIATOMACE^E.

[ 253 ]

DIATOMACE^B.

ment of the Diatomaceae, it appears impos-
sible at present to divide them satisfactorily.
The structure of the frustules of many
genera is imperfectly known and described ;
and the supposed species have hitherto been
viewed rather in relation simply to their
differences in form, than to their specific
relations.

The following synopsis, however, will
serve to aid in comparing the principal
genera scattered through the work. In it,
we have used fr. to denote the frustules as
seen in front view ; v. the valves ; granular
strige for striae resolvable into dots, ^ con-
tinuous striae being costae or canaliculi.
The genera included within brackets are
not British, or have been imperfectly de-
scribed.

Analysis of the Tribes and Genera.

* Frustules not enveloped in a gelatinous
mass, nor in gelatinous tubes.

Tribe I. Striatce. Frustules usually trans-
versely striate, but neither vittate nor
areolate.

t Valves without a median nodule.

Cohort 1. EuNOTmas. Fr. arcuate, single
or united into a straight filament.

Epithemia. Fr. single or binate, with
transverse or slightly radiant striae,
some at least continuous ; no terminal
nodules; freshwater and marine (PL 16.
fig. 32).

Eunotia. Fr. single or binate ; v. with
slightly radiant granular striae, and
terminal nodules j freshwater (PI. 51 .
fig. 27).

Himantidium. Fr. as in Eunotia, but
united into a filament ; striae parallel,
transverse; freshwater (PI. 16. fig. 36).

\Amphicampa. Fossil (PI. 18. figs. 11,

12).]

Coh. 2. MERIDIEJE. Fr. cuneate, single
or united into a curved or spiral band ;
valves with continuous or granular
striae.

Meridion. Fr. cuneate, united into a
spiral band ; striae continuous ; fresh-
water (PI. 16. fig. 28 ;_ PI. 17. fig. 7).

Eucampia. Fr. united into an arched
band; v. punctate; marine (PI. 50.
fig. 10). _

[Oncosphenia. Fr. single, cuneate, un-
cinate at the narrow end ; striae granu-
lar ; freshwater.]

Coh. 3. FRAGILAIIIE^. Fr. quadrilateral,
single or united into a filament or
chain ; v. with continuous or granular
striae.

Diatoma. Fr. linear or rectangular, united
by the angles so as to form a zigzag
chain ; striae continuous ; freshwater
and marine (PL 16. fig. 26J.
Asterionella. Fr. adherent by the ad-
jacent angles into a star-like filament ;
v. inflated at one or both ends ; fresh-
water (PI. 18. fig. 14).
Fragilaria. Fr. linear, united into a
straight close filament ; striae granular,
faint ; freshwater and marine (PI. 16.
fig. 83).

Denticula. Fr. linear, single or binate,
rarely more united ; striae continuous ;
freshwater (PI. 16. fig. 25).
Odontidium. As Denticula, but fr. form-
ing a close filament; freshwater and
marine (PI. 17. fig. 14).
Cymatosira. Frustules united, margin
undulate in front view ; valves lanceo-
late, punctate, obtuse, without a lon-
gitudinal line j marine (PI. 51. fig. 35).
Plagiogramma. Frustules quadrangular,
free, forming filaments ; valves with
two transverse-median and terminal
costae, the intervals transversely stri-
ated ; marine (PI. 51. fig. 41).
Coh. 4. MELOSIREJE. Fr. cylindrical, disk-
shaped, or globose; v. punctate, or
often with radiate continuous or gra-
nular striae.

Cyclotella. Fr. disk-shaped, mostly soli-
tary ; v. with radiate marginal striae ;
freshwater (PL 16. figs. 21, 22).
Melosira. Fr. cylindrical or spherical,
united into a filament ; v. punctate, or
with marginal radiate granular striae;
freshwater and marine (PL 17. figs. 5, 6).
Podosira. Fr. united in small numbers,
cylindrical or spherical, fixed by a ter-
minal stalk ; v. hemispherical, punc-
tate ; marine (PL 19. fig. 34).
[Mastogonia. Fr. single ; v. unequal,
angular, mammiform, circular at base,
without umbilical processes; angles
radiating ; fossil (PL 18. figs. 23 a, b
24,25). •

Pododiscus. Fr. single or united, with
a marginal stalk; v. circular, convex
(PL 17. fig. 16). ^

Pyxidicula. Fr. single or binate, free

or sessile ; v. convex ; hoop absent ? ;

freshwater and marine (PL 25. fig. 13).

Stephanodiscus. Fr. single, disk-shaped ;

DIATOMACEJE.

[ 254 ]

DIATOMACEvE.

v. circular, equal, punctate or striate,
with a fringe of minute marginal
teeth ; freshwater (PI. 18. figs. 26, 27,
28, 29).

Stephanogonia. Fr. as in Mastogonia,
but ends of valves truncate, angular,
and spinous ; fossil (PI. 18. fig. 30).

Hercotheca. Fr. single, turgid laterally ;
v. with marginal free setae (PL 18.
fig. 31).

Ooniothecium. Fr. single, constricted in
the middle, suddenly attenuate and
truncate at the ends (hence appearing
angular) (PI. 51. figs. 18-23).]
Coh. 5. SUBIRELLE.^ Fr. single or binate,
quadrilateral, oval, or saddle-shaped,
sometimes constricted in the middle;
v. with transverse or radiating conti-
nuous or granular striae, interrupted in
the middle, or with one or more longi-
tudinal rows of puncta ; often keeled.

BaciUaria. Fr. prismatic, straight, at
first forming a filament ; v. with a me-
dian longitudinal row of puncta ; ma-
rine (PL 16. fig. 14). f

Campylodiscus. Fr. single, free, disk-
shaped ; v. curved or twisted (saddle-
shaped) ; freshwater and marine (PI. 16.
fig. 16; PI. 25. fig. 18).

Doryphora. Fr. single, stalked ; v. lan-
ceolate or elliptical, with transverse
granular strise (PI. 16. fig. 29).

Podocystis. Fr. attached, sessile ; y. with
a median line, transverse-continuous
and intermediate granular striae (PI. 61.
fig. 7).

Nitzschia. Fr. free, single, compressed,
usually elongate, straight, curved or
sigmoid, with a not-median keel, and
one or more longitudinal rows of
puncta ; freshwater and marine (PI. 17.
figs. 9-13).

Cymatopleura (Sphinctocystis). Fr. free,
single, linear, with undulate margins ;
v. oblong or elliptical, sometimes con-
stricted in the middle; freshwater
(PL 16. figs. 23, 24).

Surirella. Fr. free, single, ovate, ellipti-
cal, oblong, cuneate, or broadly linear ;
v. with a longitudinal median line or
clear space, margins winged, and with
transverse or slightly radiating con-
tinuous striae ; freshwater and marine
(PL 17. figs. 21-22).

(Plagiodiscm.')

Synedra. Fr. prismatic, rectangular, or
curved; at first attached to a gelati-
nous lobed cushion, often becoming

free; v. linear or lanceolate, usually
with a median pseudo-nodule and lon-
gitudinal line ; freshwater and marine
(PL 17. figs. 23-25). ^

Tryblionella. Fr. free, linear or elliptical ;
v. plane, with a median line, transverse
striae, and submarginal or obsolete alae ;
freshwater and marine (PL 17. figs.
30-32).

Rhaphoneis=. Doryphora without a stalk.
Coh. 6. AMPHIPLEUBE^:. Fr. free, single,
straight or slightly sigmoid ; v. lanceo-
late, or linear-lanceolate, with a median
longitudinal line.

Amphipkura. Char, as above (PL 16.
fig. 7 a, b, c).

Oylindrotheca (PL 51. fig. 34).

ft Valves with a median nodule.

Coh. 7. COCCONEHXE. Fr. straight or bent,
attached by the end or side; valves
elliptical, equilateral.

Cocconeis. fr. single, compressed, ad-

nate ; v. elliptical, one of them with a

median line (PL 16. figs. 17, 18).

Coh. 8. ACHNANTHE.S:. Fr. bent, stalked

at one angle or free ; v. with a stauros.

Achnanthes. Fr. compressed, single or
rarely united into a straight filament,
curved, attached by a stalk at one
angle ; uppermost valve with a longi-
tudinal median line, lowermost with
the same, and a stauros or transverse
line ; marine (PL 16. figs. 1-4).

Achnanthidium. Fr. those of Achnanthes,
but free; freshwater (PL 16. figs. 5, 6).

Cymbosira. Fr. those of Achnanthes, so-
litary or binate, stipitate, and attached
end to end ; marine (PL 19. fig. 18).
Coh. 9. CYMBELLE-as. Fr. straight or
curved, free or stalked at the end ;
v. inequilateral, not sigmoid.

CymbeUa. Fr. free, solitary; v. na-
vicular, with a subcentral and two
terminal nodules, and a submedian
longitudinal line ; freshwater (PL 51.
fig. 2).

Cocconema. Fr. those of CymbeUa, but
stalked; freshwater (PL 16. figs. 19.
20).

Coh. 10. GOMPHONEME^;. Fr. wedge-
shaped, straight, free or stalked; v.
equilateral.

Gomphonema. Fr. single or binate,
wedge-shaped, attached by their ends
to a stalk ; v. with a median line, and
a median and terminal nodules ; fresh-
water (PL 16. fig. 34).

DIATOMACEvE.

[ 255 ]

DIATOM ACE <E.

[Sphenella. Fr. free, solitary, wedge-
shaped, involute; freshwater (PI. 19.
fig. 19).

Sphenosira. Fr. united into a straight
filament ; \. wedge-shaped, at one end
rounded, suddenly contracted and pro-
duced : freshwater (PI. 17. fig. 26).]
Coh. 11. NAVICULEJE. Fr. free, straight j
v. equilateral, or sometimes sigmoid.

Navicula. Fr. single, free, straight; v.
oblong, lanceolate or elliptical, with a
median line, a central and two termi-
nal nodules, and transverse or slightly
radiant lines resolvable into dots ;
freshwater, marine, and fossil (PI. 15.
figs. 6-9).

(Stigmaphora.}

Pleurosiama. Fr. those of Navicula, but
valves sigmoid ; freshwater and marine
(PI. 15. figs. 10-38).

(Toxonidea.)

Pinnularia. Fr. those of Navicula, but
transverse lines continuous and not re-
solvable into dots ; freshwater and ma-
rine (PL 15. figs. 1-5).

Stauroneis. Fr. those of Navicula, but
the median nodule replaced by a stau-
ros; freshwater and marine (PI. 15.
figs. 43-45).

Staurosigma. Fr. those of Stauroneis,
with a sigmoid longitudinal line.

Diadesmis. Fr. those of Navicula, united
into a straight filament; freshwater
(PI. 16. fig. 27).

Amphiprora. Fr. free, solitary or in
pairs, constricted in the middle ; v.
with a median keel, and a median and
terminal nodules, often twisted : marine
(PL 16. fig. 8).

(Donkinia.)

Amphora. Fr. plano-convex, elliptical,
oval or oblong, solitary, free or adnate,
with a marginal line and a nodule or
stauros on the flat side; freshwater
and marine (PL 16. figs. 10, 11).

Perizonium. Frustules navicular, free,
with thickened zones (PL 51. fig. 42.)

Tribe II. Vitiate. Fr. with vittae.

t Valves without a median nodule.
Coh. 12. LICMOPHOBE^J. Fr. cuneate;
vittae arched.

Licmophora. Fr. cuneate, rounded at the
broad end, radiating from a branched
stalk ; vittae curved (formed by inflec-
tion of the upper margins of the valves) ;
marine (PL 17. fig. 3),

Podosphenia. Fr. those of Licmophora
but single or in pairs, sessile upon a
thick but little-branched pedicel ; ma-
rine (PL 17. fig. 17).
Rhipidophora. Fr. those of Licmophora,
single or in pairs, upon a branched
stipes ; marine (PL 17. fig. 19).

Climacosphenia. Fr. cuneate, rounded at
the broad end, divided into loculi by
transverse septa or vittse ; marine (PL
25. fig. 9).

Coh. 13. STRIATELLEJE. Fr. tabular or fila-
mentous; vittse straight (not arched).

Striatella. Fr. compound, stalked at one
angle ; vittae longitudinal and conti-
nuous; v. elliptic-lanceolate, not stri-
ated (ord. ilium.) ; marine (PL 17. fig.
20).

Rhabdonema. Fr. as in Striatella, but
vittse interrupted, and v. with trans-
verse granular striae ; marine (PL 17.
fig. 18).

Tetracyclus. Fr. compound, filaments
compressed ; vittae alternate, interrup-
ted; v. inflated at the middle; costae
transverse, continuous ; freshwater (PL
17. fig. 28).

Tabellaria. Fr. united into a filament,
subsequently breaking up into a zigzag
chain ; vittse interrupted, alternate ; v.
inflated at the middle and ends ; fresh-
water (PL 17. fig. 27).
\_Pleurodesmium. Fr. tabular, united into
a filament, and with a transverse me-
dian hyaline band ; marine.

Hyalosira. Fr. tabular, fixed by a stalk
at one angle; vittae alternate, inter-
rupted, bifurcate at the end; marine
(PL 17. % 1).

Anaulus. Fr. rectangular, single, com-
pressed, with lateral inflections, giving
the valves a ladder-like appearance ;
marine (PL 18. fig. 7).

Biblarium. Fr. as in Tetracyclus, but
single ; fossil (PL 50. fig. 39 ; PL 18.
figs. 35-48).

Terpsinoe. Fr. tabular, obsoletely stalked,
subsequently connected by isthmi ;
vittse transverse, short, interrupted
and capitate; freshwater and marine
(PL 25. fig. 10; PI. 19. fig. 33).

Stylobiblium. Fr. compound; v. circu-
lar, sculptured with continuous striae ;
fossil (PL 18. fig. 50).]

ft V. with a median apparent (pseudo-)
nodide.

Grammatophora. Fr. at first adnate?

DIATOMACE^E.

[ 256 ]

DIATOMACE^E.

afterwards forming a zigzag chain ;
vittee two, longitudinal, interrupted at
ends, and more or less figured ; marine
(PL 1. figs. 14,15).

Diatomella. Fr. quadrangular ; vittae
two, interrupted in the middle and at
each end (PI. 61. fig. 16).

Tribe III. Areolatce. Valves circular, with
cell-like (areolar) markings, visible by ordi-
nary illumination.

Subtribe 1. Disciformes. Valves alike, with-
out appendages or processes.

Coh. 14. COSCINODISCEJE. Valves circular.

Actinocyclus. Fr. solitary; v. circular,
undulate, the raised portions appearing
as rays or bands radiating from the
centre, which is free from markings;
marine and fossil (PL 25. fig. 17).

Actinoptychus. Fr. as in Actinocyclus,
but radiating internal septa, as well as
rays ; marine and fossil (PI. 25. fig. 16).

Coscinodiscus. Fr. single; v. circular,
areolar all over; marine and fossil
(PL 61. fig. 1 ; PL 25. figs. 7, 8).

Arachnoidiscus. Fr. single ; v. circular,
not undulate, with concentric and
radiating lines, and intermediate are-
olae, absent from the centre (pseudo-
nodule); marine and fossil (PL 16.
fig. 12).

Asterolampra. Fr. single; v. circular,
finely areolar, except in the centre
and on equidistant clear marginal ra^s
radiating from the centre, which is
traversed by radiating dark lines
(septa) alternating with the marginal
rays; fossil (PL 25. fig. 5).

Aster omphalos. As Asterolampra, but
two of the central dark lines parallel,
and the corresponding marginal ray
obliterated ; fossil (PL 25. fig. 2 ; PL
18. fig. 15).

Halionyx. Fr. single ; v. circular, with-
out septa, with rays not reaching the
centre, and with intermediate shorter
rays; between the rays transverse
(concentric?) areolar lines; fossil (PL
18. fig. 51).

Odontodiscus. Fr. single, lenticular; v.
covered with puncta (areolse) arranged
in radiating rows or excentrically
curved lines, and with erect marginal
teeth; fossil (PL 18. fig. 52).

Omphalopelta. As Actinoptychus, but
upper part of margin of valves with a

few erect spines; fossil (PL 18. fig.
63).

Symbolophora. Fr. single, disk-shaped;
v. with incomplete septa radiating
from the solid angular umbilicus, and
intermediate bundles of radiating lines ;
marine and fossil (PL 25. fig. 6 ; PL 18.
figs. 64, 55, 56).

Systephania. Fr. single; valves circular,
areolar, -without rays or septa, with a
crown of spines or an erect membrane
on the outer surface of each valve;
fossil (PI. 18. figs. 57, 58).
Coh. 15. ANGULIFEILS:. Valves angular.

Amphitetras. Fr. at first united, after-
w7ards separating into a zigzag chain,
rectangular; v. rectangular, the an-
gles often produced; marine (PL 16.
%?).

Amphipentas. Fr. solitary ; v. penta-
gonal ; fossil (PL 25. fig. 11).

Lithodesmium. Fr. united into a straight
filament ; v. triangular, one side plane,
the others undulate; marine (PL 17.
fig. 4).

Tribe IV. Appendiculatce. Valves with
processes or appendages, or with the angles
produced or inflated.

Coh. 16. EFPODISCE^:. Fr. disk-shaped ;
v. circular.

Eupodiscus. Fr. single, disk-shaped ;
v. circular, with tubular or horn-like
processes on the surface; freshwater
and marine (PL 16. figs. 30, 31).
[Auliscus. As Eupodiscus, but processes
obtuse and more solid ; fossil (PL 18.
fig. 60).

Insilella. Fr. single, fusiform ; v. equal,
with a median turgid ring between
them = terete Biddulphia; marine.]
Coh. 17. BIDDULPHIEJE. Fr. flattened ; v.
elliptical or suborbicular.

Siddulphia. Fr. rectangular, more or
less united into a continuous or zigzag
filament ; the angles inflated or pro-
duced into horns; v. convex, centre
usually spinous ; marine (PL 16. fig.
15; PI. 19. fig. 9).

Isthmia. Fr. rhomboidal or trapezoidal,
cohering by one angle; angles pro-
duced; marine (PL 17. fig. 2).

Chcetoceros. Fr. compressed ; v. equal,
with a long spine or filament on each
side ; marine (PL 50. fig. 47).

Rhizoselenia. Fr. elongate, subcylindri-
cal, marked with transverse or spiral

DIATOMACE^E.

[ 257 ]

DIATOMACEJE.

lines, ends oblique or conical, and with
one or more terminal bristles ; marine
(PI. 50. fig. 46).

Corinna. Fr. united into semicircular
bands; angles produced, spiniferous,
intermediate portion hemispherical,
septate; valves ellipsoid, transversely
bicostate, apiculate at each end.

\_Hemiaulus. Fr. single, compressed, rec-
tangular, angles produced into tubular
direct processes, those on one valve
longer than those on the other ; fossil
(PL 25. fig. 3).

Syringidium. Fr. single, terete, acu-
minate at one end, two-horned at the
other j marine (PI. 18. figs. 32, 33).

Periptera. Fr. single, compressed ; v.
unequal, one simply turgid, the other
with marginal wings or spines ; fossil
(PI. 18. figs. 66, 67).

Didadia. Fr. single ; v. unequal, one tur-
gid and simple, the other two-horned ;
fossil (PI. 18. figs. 61-65).

Trinacria. Porpeia. Hydrosera (PI. 51.
fig. 40). Solium. Zygoceros. Gly-
phodiscus. Attheya (PI. 51. fig. 39).]
Coh. 18. ANGULAT.E. Valves angular.

Triceratium. Fr. free ; v. triangular, each
angle with a minute tooth or horn ;
marine (PI. 17. fig. 29).

[Syndendrium. Fr. single, subquadran-
gular; v. unequal, strictly turgid, one
smooth, the other with numerous me-
dian spines or little horns branched at
the ends (PI. 18. fig. 59).]

Rabenhorst makes the Angulatse a sub-
family of Biddulphieae ; comprising the
European genera Triceratium, Trinacria,
and Lithodesmium.

** Frustules enveloped in a mass of gelatine,
or contained in gelatinous tubes, forming
a frond,

Mastogloia. Frond mammillate ; frus-
tules like Navicula, but hoops with
loculi ; freshwater and marine (PI. 51.
fig. 26).

Dickieia. Frond leaf-like ; frustules like
Navicula or Stauroneis', marine (PI. 19.
fig. 16).

Berkeleya. Frond rounded at base, fila-
mentous at circumference ; frustules
navicular; marine (PI. 19. fig. 8).

Homceocladia. Frond sparingly divided,
filiform ; frustules like Nitzschia, ma-
rine (PI. 19. fig. 15).

Rhaphidoglcea. Frustules those of Am-

phipleura, tufted in radiating gelatinous
filaments (PL 19. fig. 11).
Colletonema. Frond filamentous, fila-
ments not branched ; fr. like Navicula
or Pleurosigma ; freshwater.
Schizonema. Frond filamentous, branched;
fr. like Navicula ; marine (P1.19. fig. 12).
Encyonema. Frond filamentous, but little
branched ; fr. like Cymbella ; fresh-
water (PL 19. fig. 10).
Syncyclia. Fr. those of Cymbella, united
in circular bands, immersed in an
amorphous gelatinous frond ; marine
(PL 19. fig. 14).

Frustulia. Fr. those of Navicula, irregu-
larly scattered through an amorphous
gelatinous mass; freshwater (PL 19.
% 17).

Micromega. Fr. those of Navicula, ar-
ranged in rows, in gelatinous tubes,
or surrounded by fibres, these being
enclosed in a filiform branched frond ;
marine (PL 17. fig. 8).
Many other species are noticed and
figured in this work under the genera,
which have not been described with suffi-
cient brevity to allow of their being tabu-
lated, or are not well established.

BIBL. Ralfs, Ann. N. H. 1843, xi. 447.
xii. 104, 271, 346, 457; Thwaites, Ann.
N. H. 1847, xix. 200, xx. 9, 343 ; 1848, i.
161 ; Smith, Br. Diat. ; Bailey, Silliman's
Jn. xli.,xlii. ; id. Ann. N. H. 1851, viii. 157,
and Smithson. Contrib. 1854; Ehrenberg,
Inf.; id. Berl. Abh. 1839, 1840; id. Berl.
Ber. passim ; id. Mikrogeologie ; Brebisson,
Diatomees-, Kiitzing, Bac. and Sp. Algarum-,
Pritchard, Inf. (full account of species)-,
Braun, Verjung. (Ray Soc. 1853) ; Nageli,
Einzell. Alg. 9: Focke, Physiol Studien,
1853 ; Meneghini, SulV Animalit. &c. (Ray
Soc. 1853) ; Gregory, Diat. Clyde, 1857 ;
Smith (South France} Qu. M. Jn. 1855;
id. (Pyrenees}, 1857 ; Greville, Qu. M. Jn.
1859 (Californian), 1865 (Hong Kong),
1 ; H. L. Smith, Ann. N. H. 1869, iv. 218;
Grunow, Verh. zool.-bot. Gesellsch. Wien.
1858, '60, '62; Qu. M. J. 1877, 166 (Hon-
duras) ; Ny lander, Diat. Fennice fossil, addit.
1861; Weisse, Schwarz-Erde (Tscherno-
Sjom), 1855 ; Heiberg, Cotisp. Diat. danic.
1863 (6 pis.); Wenham, M. Mic. Jn. ii.
158 (illuminating} ; Qu. M. J. 1855, iii. 244 ;
Wallich, Mic. Tr. 1860, 129, viii. 36;
Ann. N. H. 1863, xi. 351 ; M. M. J. 1877,
xvii. 61 ; Schultze, Struct, d. Diat.-Schak,
Verhandl. Naturh. Ver. p-euss. Rheinl. xx.

S

DIATOMELLA.

[ 258 ]

DICLADIA.

1 (figs.), abr. in Qu. M. Jn. 1863, iii. 120;
Antelminelli, Qu. M. Jn. 1868, 254 (repro-
duct.) ; Flogel, Arch. mikr. An. iv. 472 ;
Macdonald, Ann. N. H. 1869, iii. 1 ; Ma-
noury, Diat. 1870; Fritsch & Miiller,
Skulpttir, 1870 (excellent photographs) ;
Donkin, Br. Diat. 1871; Rabenhorst, Fl.
Alg. i. ; Pfitzer, Hanstein's Bot. Abh. 1871,
ii. 120; Millardet and Kraus, Compt.
rendus, Ixvi. 505 ; Askensky, Bot. Zeit.
1869, 790; Luders, Bot. Zeit. 1862 (colouring
matter); Hickie, Schumann's Diat. formulae,
M. M. J. 1875, xiv. 6; Habirshaw, Catal
Diat. 1877 ; Lewis, Diat. of United-St. Sea-
board; Schmidt, Atlas (Jigs, of all species
#c.), 1878; Pettitt, Jn. Mic. Soc. 1878, i.
237, pis. (Campbell Island), & Bull. Soc.
Bot. d. France, xxiii. & xxiv. (Kitton, M.
M. Jn. 1877, xviii. 10 & 65 ; classn.} ; Cox,
Amer. Jn. Mic. 1878, iii. 100; Heurck,
Syn. Diat. 1880 (Belgique, pis.) ; Cleve &
Grunow, Diat. Arct. 1880; Lanzi, An.
Soc. Beige (Jn. Mic. Soc. ii. 1879, 38,
thallus); Mereschkowsky, Bot. Zeit. 1880,
xxxviii. 529 (Jn. Mic. Soc. 1881, i. 102) ;
Borscow, Bac. Russlands, 1873; Engel-
mann, Bot. Zeit. 1879; Hallier, Diat. 1880
(movement}.

DIATOMELLA, Grev. D. Balfouriana,
Gr. = Grammatophora B., Smith (PL 61.
fig. \&)=Disiph<mia australis, Ehr.

DIOEL'LA, Werneck.— A doubtful ge-
nus of Infusoria (Berl. Ber. 1841, 377).

DICHONE'MA, N. ab Es.— A genus of
Hymenomycetous Fungi, inhabiting tro-
pical America and Polynesia.

D. sericeum consists of a reticulation of
Confervoid filaments, interlaced with myce-
lium, and at length, like Cora, producing a
distinct hymenium which cracks into
scattered patches. This genus is some-
times called Dictyonema. Spreading in an
orbicular form, from branches of trees ; a
curious microscopic object (Leighton).

BIBL. Esenb. N. Acta, xiii. 12.

DI'CHROISM (double colour) is the term
applied to the property possessed by many
doubly refracting crystalline substances, of
exhibiting two colours when light is trans--
mitted through them in different positions.
It may be observed under the microscope in
crystals of the tourmaline, the acetate of
copper, the chloride of palladium, and the
oxalate of chromium and potash, or of
chromium and ammonia.

Dichroism depends upon the absorption of
some of the coloured rays of the polarized
light in their passage through the crystal —

this absorption varying with the different
relative positions of the planes of primitive
polarization of these rays to the axis of
double refraction of the crystals, so that the
two pencils formed by double refraction are
differently coloured.

In the acetate of copper, the two colours
are deep blue and yellowish green ; in the
chloride of palladium, they are red and
green ; in the oxalate of chromium and
potash they are blue and green, and in the
tourmaline they are not always the same.
The variation in colour is entirely indepen-
dent of the thickness of the crystal.

BIBL. Brewster, Phil. Tr. 1819, and
Optics, 353; Herschel, Encyc. Metr. art.
Light, 1064.

DICKIEI'A, Berkeleyand Ralfs.— A ge-
nus of Diatomaceae.

Char. Frustules navicular, irregularly
scattered through a flat undulate frond or
subgelatinous layer, narrowed at the base so
as to appear substipitate.

D. ulvoides (PI. 19. fig. 16: a, frond,
nat. size ; b, portion, magnified ; c, prepared
frustule, front view ; d, valve). Stipes very
short, capillary ; frond oblong, irregularly
lobed or creniilate; frustules oblong, ob-
tuse-angled, truncate at the ends : valves
oblong, with a stauros; length of frond
1 to 1^" ; of frustules, 1-1000 to 1-720" ;
marine.

Frond very pale purplish white. Recent
frustules with a round colourless spot at
each of the four angles (in the front view).
Found in shallow pools between high and
low-water mark.

D. pinnata. Frond irregularly divided,
or laciniate ; v. like Navicula. Marine.

BIBL. Berkeley and Ralfs, Ann. N. H.
1844, xiv. 238, and 1851, viii. 204 ; Kiit-
ziug, Bacill. and Sp. Alg. 109 ; Thwaites,
Ann. N. H. 1848, i. 171 ; Smith, Brit. Diat.
ii. 166.

DICKSO'NIA, L'He-ritier.— A genus of
Dicksonieae (Polypodiaceous Ferns), in-
cluding fine arborescent species. All exotic.

DICKSO'NIE^E.— A family of Polypo-
diaceous Ferns.

Genera : Onoclea, Hypoderris, Woodsia,
Sphceropteris, Dicksonia, and Deparia.

BIBL. Hooker, Syn. Fil. 45.

DICLA'DIA, Ehr.— A genus of Diato-
macese.

Char. Frustules single; valves unequal,
one turgid and simple, the other two-
horned, the horns sometimes branched.
Marine and fossil.

DICOEYNE.

[ 259 ]

DICTYOCHA.

D. capreohts (PI. 18. figs. 63, 64); D. an-
tennata (PI. 18. fig. 61) ; D. bulbosa (PI. 18.
fig. 62) ; D. dathrata (PI. 18. fig. 65).

BIBL. Ehrenb. Bert. Ber. 1844, 73, and
Mikrogeologie ; Bailey, Sillim. Jn. 1856;
Greville, Mic. Tr. 1865, 56, 98.

DICORY'NE, Allm.— A genus of Hy-
droid Polypi, fam. Atractylidae.

D. conferta. On old shells, Buccinum, &c.

BiBL.'Hincks, Brit. Zooph. 105.

DICOTYLEDONS.— One of the two
great divisions of the Angiospermous Flow-
ering Plants, synonymous with the Exogens
of Decandolie, and opposed to Monocotyle-
dons,— the name being derived from the
condition of the embryo prevailing through-
out the vast majority of plants included in
this assemblage. As in all other natural
groups, instances occur wherein the parti-
cular character from, which the name is
derived, the presence of a pair of cotyledons
in the embryo, is absent, as in Orobanche,
&c. (like the Orchidaceae and other plants
among the Monocotyledons) ; but in these
cases the plants agree generally with Dico-
tyledons in all the rest of the prominent
characters, such as the structure of stem,
leaves, plan of flower, &c. See VEGETABLE
KINGDOM, WOOD, and SEED.

DICRANA'CE^.— A family of Apocar-
pous operculate Mosses, branching by in-
novations, or with the tops of the fertile
branches several times divided. Leaves
lanceolate or subulate, channelled-concave,
with a nerve mostly dilated and flattened,
rarely slender, scarcely cylindrical. The
cells prosenchymatous (often mingled with
parenchymatous), rarely papillose, mostly
empty, often thickened upwards, thereby
rounded or elliptical ; the basilar cells ar-
ranged in a curved manner at the margins
of the leaves, distinctly diverse, paren-
chymatous, lax, thick, large, flat or with a
more or less thick and patel lif orm front, de-
licate or robust, hyaline, fuscous, brown or
purple, ultimately marcescent, mostly very
conspicuous (alar cells). Capsule oval or
cylindrical, arched or straight, with a su-
bulate operculum. Peristome, if present,
purple, teeth trabeculate.

British Genera.

Blindia. Calyptra dimidiate, hood-sha-
ped, peristome wanting or simple, then
of sixteen equidistant, lanceolate, distantly
articulated, smooth, slender teeth, slightly
trabeculate within, purple, cartilaginous.
Capsule exannulate.

Dicranum. Calyptra dimidiate. Peri-
stome simple, teeth connate at the base into
a more or less emergent membrane, or equi-
distant and arising below the orifice of the
capsule, split more or less deeply, even in
some cases to the base, into two or rarely
more free arms, purple below, trabeculate-
nodose above (figs. 169 & 170).

Fig. 169.

Fig. 170.

Fig. 171.

Dicranum palustre.

Fig. 169. Mouth of the capsule with the peristome
everted. Magnified 40 diameters.

Fig. 170. Portion of the peristome. Magnified 100
diameters.

DI'CRANUM, Hedw.— A genus of Di-
cranacese (Apocarpous operculate Mosses),
including numerous British spscies, very
varied in size and habit ; some, such as D.
scoparium, very common (see ANGSTRCEMIA
and LEUCOBRYUM).

BIBL. Wilson, Bn/ol. Brit. p. 61.

DICTYD'IUM, Schrad.
— A genus of Myxomycetes;
exceedingly elegant little
plants, growing upon rotten
wood. The peridium is ex-
cessively delicate, and the
peculiar capillitium adherent
to it ; so that, when the
spores are expelled, the trans-
parent case appears like a
cage, formed of the veins
alone. There are no fila-
ments mingled with the
spores. D. umbilicatum(tig.
171) is a British species ; it
is of a brownish-purple co-
lour until the spores are dis- umb._

charged, then hyaline ; it is licatum.
gregarious in its habit of Magn. 25 diam.
growth.

BIBL. Berk. Hook. Br. Fl. v. pt. 2. 317;
Greville, Sc. Crypt. Fl. pi. 153 ; Fries, Syst.
Myc. iii. 164; Schrad. Nov. Gen. 11;
Corda, Ic. Fung. v. pi. 3. fig. 36.

BICTY'OCHA, Ehr.— The nature of the
curious bodies, of which the genus Die-
tyocha consists, is unknown. They consist

D1CTYOCYSTA.

[ 260 ]

DICTYOTACE^E.

of a single piece ; hence they are not Diato-
maceae. This piece is siliceous and loosely
reticulate or stellate. Marine and fossil.

Kiitzing enumerates twenty-nine spe-
cies ; distinguished principally by the num-
ber of external spines and internal are-
olse ; they vary in diameter from 1-1150
to 1-370".

D. gracilis (PI. 25. fig. 19, perspective
view; 20, side view; 21, view from above).

D. fibula (PL 51. fig. 5).

BIBL. Ehrenberg, Berl. Abh. 1838, and
Mikrog. ; Kiitzing, Bacill. and Sp. Alg. 142 ;
Pritchard, Inf. 735.

DICTYOCYS'TA, Ehr.— A genus of
Peritrichous Infusoria.

Char. Free ; enclosed in siliceous per-
forated or pitted loricae, with an anterior
fringe of long cilia, and an inner circle of
uncini ; surface smooth. 6 species. Marine.
(Kent, Inf. 624,)

DICT^OLAMPRA, Ehr.— A genus of
Diatomacese.

Char. Frustules single ; no internal septa ;
valves equal, cellular (apparently) in the
middle, the smooth margin radiate.

D. stetta (PI. 18. fig. 68). The only spe-
cies. Found among Polycystina from Bar-
badoes.

BIBL. Ehr. Ber. Berl Akad. 1847, 64.

DICTYOP'TERIS, Presl.— A genus of
Polypodiaceous Ferns, deriving their name
from the reticulated arrangement of the
veins, = Polypodium, pt.

DICTYOPYX'IS, Ehr., Grev.— A genus
of marine Diatomaceae.

Char. Frustules areolar, united into short
bands ; valves convex, cupuliform, hoop
absent, = Pyxidicula, pt.

D. brevis, Grev. ; I), cruciata, Ehr.

BIBL. Grev. Mic. Jn. 1862, 22 (fig.);
"Ebx.Berl.Ahk. 1844; Pritchard, /w/825;
Rabenhorst, Fl Alg. i. 36.

DICTYOSI'PHON, Grev.— A genus of
Dictyosiphonaceae (Fucoid Algae), repre-
sented in Britain by a common branched
filamentous sea- weed (D. faniculaceus),
with the frond growing from one to several
feet long, of an olive or rusty-brown co-
lour. The fructification at present known
consists of ovoid sporanges, imbedded in
the cellular tissue of the branches, lying
lengthways; they open by a pore at the
surface.

BIBL. Harvey, Mar. Alg. 40, pi. 7 D ;
Greville, Alg. Brit. pi. 8 ; Thuret, Ann. Sc.
Nat. 3 ser. xiv. 238.

DICTYOSIPHONA'CE^E.— A family

of Fucoideae. Olive-coloured sea-weeds
with cylindrical branched fronds, the oospo-
ranges imbedded lengthways in the sub-
stance of the frond, opening by a pore on,
the surface.

British Genera.

Dictyosiphon. Root a minute naked
disk ; frond cylindrical, branched ; oospo-
ranges scattered irregularly, solitary or in
dot-like sori.

Striaria. Root a minute naked disk ;
frond cylindical, branched; oosporanges
arranged in transverse lines on the surface
of the frond.

BIBL. See the genera.

DICT YOSPH^E'RIUM, Nag.— A genus
of Palmellaceous Algae.

Char. Cells oblong, green, connected by
filaments, united into free, rounded, plate-
like layers. Freshwater.

2 species. D. Ehrenbergii (PI. 3. fig. 11).

BIBL. Nageli, Einzell. Alg. 73 ; Archer,
Qu. Mic. Jn. 1866, 127.

DIOTYOSPOR'IUM, Corda.— A genus
of Torulacei (Coniomycetous Fungi) con-
taining one species, D. ele-
gans (fig. 172), a minute Fig. 172.
fungus growing upon oak
which has been stripped of
its bark ; very remarkable
for the reticulated charac- 1
ter of its spores.

BIBL. Berk. & Br. Ann.
Nat. Hist. 2 ser. v. 460 ;
Corda, Icon. Fung. ii. pi. 8.
fig. 29.

DICTYO'TA, Lamx.— A genus of Dic-
tyotaceae (Fucoid Algae), containing one
British species, D. dichotoma (PI. 4.
fig. 2), common between tide-marks, on
rocks, &C.J remarkable for itsdichotomously
divided membranous frond, of olive-green
colour, 3 to 12" long, which, on distinct
individuals, produces three kinds of re-
productive organs, viz. \.tetraspores, divided
crucially, and either scattered or arranged
in sori ; 2. spores grouped in sori and covered
by the common epidermis of the thallus ;
and 3. antheridia, in patches on either face
of the thallus.

BIBL. Harvey. Brit, Alg. 39, pi. 7A; Phyc.
Brit. pi. 103 ; Greville, Alg. Brit. pi. 10 ;
Thuret, Ann. Sc. Nat. 4 se"r. iii. 7, pi. 2.

DICTYOTA'CE^E.— A family of Fucoi-
deae. Olive-coloured inarticulate sea- weeds,
with large spores like those of Fucaceas,
superficial, in definite spots or lines (sori),

Dictyosporium

elegans.

Spores magnified
1000 diameters.

DICTYOXYPHIUM.

[ 261 ]

DIDYMOCHL^ENA,

or scattered. Root coated with woolly
fibres. Frond flat.

Many other genera are included in this
family by most authors ; but Thuret has
pointed out that the genera here named
produce spores, while the structures de-
scribed as such in the others are oospo-
ranges. PADINA presents some interesting
points of microscopic structure. All the
genera are formed of very regular muri-
form parenchyma.

British Genera.

Haliseris. Frond dichotomous, with a
midrib.

Padina. Frond ribless, fan-shaped, con-
centrically streaked. Sari linear, concen-
tric, bursting through the epidermis.

Zonaria. Frond ribless, lobed, concen-
trically striate. Sori roundish, containing
spores and jointed threads.

Taonia. Frond ribless, irregularly cleft,
some what fan-shaped. Sori linear, concen-
tric, superficial, alternating with scattered
spores.

Dictyota. Frond ribless, dichotomous.
Sori roundish, scattered, bursting through
the epidermis, or (on distinct individuals)
scattered spores.

For other genera often included here, see
SPOROCHNACE^PUNCTARIACE^DICTYO-
SIPHOXACE^;, and CUTLERIACE^.

BIBL. See the genera.

DICTYOXYPH'IUM, Hooker.— A ge-
nus of Lindsayeae (Polypodiaceous Ferns).
Exotic.

DIG YE' MA, K611.— A genus of Infuso-
ria (?), allied to Opalina.

I). Mulleri is found in the kidneys &c. of
Cephalopoda.

BIBL. Erdl, Erichs. Arch. 1843, 162;
Kolliker, Wiirzburg Ber. 1849 ; Clap, and
Lachm. Infm. ii. 201.

DIDER'MA, Pers.— A genus of Myxo-
mycetes, consisting of minute epiphytic
plants of tolerably persistent structure
(fig. 173). The peculiar cha-
racter resides in the double Fig. 173.
layer of the peridium, the
outer bein£ smooth and crust-
like, fragile and dehiscent,
while the inner is very deli-
cate and evanescent. The spe-
cies vary in habit, being either
stipitate with the stalk more
(Leangium, Lk.) or less (Leo- Magnified 25
carpus, Lk.) distinct in dif- diams.
ferent cases, and sessile. A

dozen species are recorded as British, of
which the sessile D. globosum, and the ob-
scurely stalked D. vernicosum, appear the
commonest.

BIBL. Berk. Hook. Brit. Fl. v. pt. 2.
310 ; Ann. N. H. i. 257 ; Crypt. Bot. 337 ;
Fries, Syst. Myc. iii. 96 ; Summa Veg. 450 ;
Greville, Sc. Crypt. Fl. pis. 3, 122 & 132 ;
Corda, Ic. Fung.

DIDIM'IUM, Stein.— A genus of Peri-
trichous Infusoria.

Char. Free, ovate, or subcylindrical, with
an anterior and posterior ciliary wreath;
snout-like in front.

D. nasutum. Pond- water ; length 1-300".
(Kent, Inf. 638.)

DIDYM'IUM, Schrad. — A genus of
Myxomycetes, consisting of minute plants
growing upon leaves, bark, rotten wood,
&c. (fig. 174), distinguished by its double
peridium, of which, however, the inner
membranous layer is the true case
(bursting irregularly), while the Fig. 174.
outer forms a kind of bark, which
breaks up into little furfuraceous
scales or mealy down. Filaments
exist twining among the spores
adherent to the peridium. Six-
teen species are recorded as Bri- f idy««™»

,. i *• in 1.1 hemisphse-

tish, several of which are not ricum.
uncommon. They vary in habit, Magnified
like the Didermce, being either 2» diams.
stalked, sessile, or adnate to their
support. D. farinaceum is figured by
Sowerby as Trichia sphcerocephala.

BIBL. Berk. Hook. Br. Fl. v. pt. 2. 312 ;
Ann. N.H.i. 257, 1850, v. 365, xiii. 459;
Crypt. Botany, 337 j Fries, Syst. Myc. iii.
113 ; Summa Veg. 451 ; Sowerby, Fungi.
pis. 12, 240, 412; Corda. Ic.Fung.

DIDYMOCHL^E'NA, Desv.— A genus

Fig. 175.

Didymochlaena sinuosa.

Fig. 175. A sorus, from above. Magn. 20 diams.
Fig. 176. Transverse vertical section of ditto.

DIDYMOCLADON.

[ 262 ]

DIDYMOSPORIUM.

of Aspidieae (Polypodiaceous Ferns), with a
curious elliptical indusium opening on each
side (figs. 175 & 176). Exotic.

DIDYMO'CLADON, Kalfs.— A genus
of Desmidiaceae.

Char. Cells single, constricted at the
middle, end view tri- or quadrangular ; each
angle with two processes, one lateral and
in the front view nearly parallel with the
corresponding one of the other segment,
the other superior and divergent.

The two processes distinguish this genus
from Staurastrum.

D.furcigerus (PI. 14. fig. 32, front view;
fig. 56, end view^).

a, end view triangular.
/3, end view quadrangular.
Length, including processes, 1-830".
BIBL. Ralfs, Brit. Desmid. 144.
DIDYMOHE'LIX, Griffith.— A genus of
Oscillatoriaceae (Confervoid Algae), with the
threads consisting of pairs of microscopic,
interlacing, ferruginous, spiral filaments j
probably surrounded by gelatine.

It seems to have no relation with Gal-
lionella as formerly supposed.
Found in ferruginous bog- water.
The structure of the compound filaments
of which this beautiful and curious organism
consists requires great care to elicit, both
on account of their minute size and their
peculiar form. The breadth of the filaments
is from 1-5000 to 1-30,000", the average
1-10,000 to 1-20,000". Filaments imbued
with peroxide of iron, containing no silica,
or not more than a trace, such as is naturally
invariably associated with the peroxide.
"With hydrosulphuret of ammonia, they be-
come black. Acted upon slowly with di-
lute muriatic acid, the colour gradually
vanishes, a very transparent colourless cast
of the original being left. If the compound
filaments are macerated for some time in
distilled water, the filaments will separate
(PI. 1. fig. 10 d). Under a J-inch object-
glass, the filaments present the appearance
represented in PI. 1. fig. 10 a. When a
higher power is used, they appear as in fig.
10 6, which represents them as seen when
too much liquid is contained between the
slide and the cover, or when the proper
correction is not made for the thickness of
the glass coyer and of the liquid, or \vhen
lying edgewise. When lying flat upon the
slide, and the correction is perfect, they ap-
pear as in PI. 1. fig. 10 c.

In the natural state, a quantity of yel-
lowish-brown gelatinous matter is always

found in the water containing the filaments.
In the ferruginous gelatine are found some
fibres of a very minute Nostochaceous
plant, probably Anabaina subtilissima,
Kiitz. Didymohelix is by no means com-
mon, even in waters which contain a very
copious ferruginous deposit. It is found in
ditches in Dumfriesshire, 10 or 12 inches in
thickness.

It may be preserved either in the dry
state, in chloride of calcium, or in balsam.

We have enumerated this as a test-object
for the general excellence of a high-power
object-glass, also of the observer's manage-
ment of the microscope. See TEST-OBJECTS.
BIBL. Griffith, Ann. Nat. H. 1853, xii.
438 ; Davies, M. M. Jn. 1877, xvii. 54.

DIDYMO'PRIUM, Kiitz.— A genus of
Desmidiacese.

Char. Cells with a bidentate or bicrenate
process on each side, united into an elon-
gated, fragile, cylindrical, and regularly
twisted filament. (Sheath either present,
wanting, or indistinct.)

Differs from Desmidium in having only
two processes, and not being angular, and
in the number of rays of the endochrome
in the side view not depending upon the
number of angles.

D. Borreri (PL rl. fig. 11). Joints in-
flated, barrel-shaped, longer than broad :
side view circular ; angles bicrenate. (Sheath
wanting or indistinct.)

The delicate longitudinal lines were pro-
prosed by Jenner as a test- object for the
power of the microscope; they are best seen
in the empty cells when dried. Breadth
of filament 1-1030".

D. Gremllii (PI. 14. fig. 5 ; fig. 6, side
view). Joints broader than long, with a
thickened border at their junction ; side
view broadly elliptic; angles bidentate.
(Sheath distinct.) Breadth of filament
1-470".

BIBL. Ralfs, Brit. Desmid. p. 55.
DIDYMOSPO'RIUM, Nees.— A genus
of Melanconiei (Stylosporous Fungi), grow-
ing upon shoots of trees. The only British
species, D. profusum, Grev., has very mi-
nute, oblong, uniseptate spores, at first glued
together like a depressed conical nucleus,
beneath the epidermis, afterwards bursting
through and becoming free. D. elevatum}
Lk. = Melanconium bicolor, Nees.

Greville's plant, however, has not truly
unicioptate spores, and is rather a Melanco-
nium, referred as a conidiiferous form by
Tulasne to Melanconium stilbostoma.

DIFFLUGIA.

[ 263 ]

DIMORPHINA.

BIBL. Berk. Hook. Brit. Flor. v. pt. 2.
357; Ann. N. H. 1840, vi. 438; Greville,
So. Crypt. jF7.pl. 212. fig. 1 (as Stilbospord);
Tul. Carp. ii. 120.

DIFFLU'GIA, Leclerc.— A genus of
Rhizopoda, of the family Arcellina.

Char. Contained in a spherical or oblong,
urceolate, incrusted carapace, from the an-
terior extremity of which are emitted
variable numerous or multifid tentacular
expansions. Freshwater.

The carapace is membranous, incrusted
with minute grains of sand (and carbonate
of lime P) ; in some it is covered with de-
pressions or tubercles ; these form the genus
Euglypha, D. D. Enchelys forms gem-
mae, and also resolves itself into four
" spores."

Species very numerous.

D. proteiformis, E. (PI. 30. fig. 39.) Ca-
rapace oval or almost spherical, covered
with minute grains of sand; length 1-240".

D. oblonga, E. (D. ylobulosa (?), D.).
Carapace oval, oblong, or rounded, smooth,
brownish; length 1-200".

BIBL. Leclerc, Mem. Museum, ii. 474 ;
Ehr. Inf. 130; and Berl. Ber. 1840; Du-
jardin, Inf. 248; Schlumberger, Ann, Sc.
Nat. 1845, iii. 254 ; Schneider, Ann. N. H.
1854, xiv. 332 ; Clap. & Lachm. Inf. 447 ;
Lang, Qu. Mic. Jn. 1865, 285 ; Tatem, M.
M. J. 1870, iv. 313; Archer, Qu. M. J.
1877, xvii. 115.

DIGLENA, Ehr. — A genus of Rotatoria,
of the family Hydatinsea.

Char. Eyes two, frontal ; foot forked.

There are no other appendages than the
foot and the rotatory organ.

Nine species.

D. lacustris (PL 43. figs. 21, 22). Body
oval, transparent, truncate in front ; foot
suddenly attenuate, somewhat more than
l-4th of the body in length ; toes l-3rd
part of the foot in length ; freshwater ;
length 1-70".

BIBL. Ehr. Infus. 441 ; Gosse, Ann. N.
H. 1851, viii. 200.

DILEP'TUS, Duj.— A genus of Infuso-
ria, fam. Trichodina.

Char. Body fusiform, prolonged ante-
riorly in the form of a swan's neck, with a
lateral mouth at the base of the prolonga-
tion ; entire surface covered with vibratile
cilia, which are more distinct in front and
near the mouth.

D. folium, D. (PL 30. fig. 40). Body
very flexible, in the form of a lanceolate
leaf, narrowed in front ; with nodular, reti-

culated, irregular ribs j freshwater ; length
1-160 to 1-120".

D. anser (Amphileptus anser, E.).

D. margaritifer (Amphileptus marg., E.).

Dujardin separates these species from the
genus Amphileptus, on account of their not
possessing a reticulated integument, and
their undergoing diffluence. 01. & Lachm.
unite them with Amphileptus.

BIBL. Duj. Infus. 404.

DILOPHOS'PHORA, Desm.— A genus
of Sphaeronemei (Stylosporous Fungi), con-
sistingofSphferia-like plants (without asci),
growing upon the leaf-sheaths and glumes

Fig. 177.

Dilophosphora graminis.
Spores. Magnified 800 diams.

of grasses ; remarkable for the curiously ap-
pendaged spores (fig. 177).

D. graminis, Desm. = Spharia Alopecuri,
Fries. Sometimes very destructive to wheat-
crops in the south of England.

BIBL. Desmazieres, Ann. Sc. Nat. 2 se>.
xiv. p. 4. pi. 1. fig. 2.

DIMASTIGOAU'LAX, Dies. = Peridi-
nium cornutum, Ehr., Ceratium c., Clapa-
rede & Lachmanu. (Kent, Inf. 462.)

DIMEREGRAM'MA, Pritch.— A genus
of Diatomaceae.

Char. Frustules quadrangular, two or
more together; valves (undulate, Rab.) with
transverse costae interrupted by a smooth
longitudinal line.

Several species.

BIBL. Pritchard, Inf. 123 ; Gran. Wien.
Verh. 1862; Gregory, Diat. of Clyde. 22;
Rabenhorst, Flor. Alg. i. 123.

DI'MONAS, Kent.— A genus of Flagel-
late Infusoria.

Char. Free, ovate or pyrif orm j flagella
2, equal ; mouth very dilatable.

Two species ; in infusions, fresh and salt ;
hay. (Kent, Inf. 421.)

DIMORPHI'NA, D'Orb. — A hyaline
Foraminifer, in which the early chambers
have the alternate growth of a Polymor-
phina, and the later ones the linear arrange-
ment of a Nodosaria. D. tuberosa, D'Orb.

DIMORPHOCOCCCJS.

[ 264 ]

DINOPHYSIS.

Fig. 178.

Modele no. 60, is the type of this dimor-
phous Polymorphina. Fossil and recent.

BIBL. Parker and Jones, Ann. N. H. ser.
3. xvi. 28 ; D'Orb. For. Foss. Vien. 221.

DIMORPHOCOCCUS, Braun.— A ge-
nus of Palmellaceous Algae ; consisting of
free botryoidal substipitate groups of ovate
or lunate green cells, 4 in each.

D. lunatus (PI. 61. fig. 43). In pools ;
Germany.

BIBL. Braun, Alg. Unicell. 44.

DINEMASPO'RIUM, Le>.— A genus of
Sphaeronemei (Stylosporous Fungi), con-
sisting of minute plants forming spots upon
the leaves of grasses. D. gramineum, Lev.,
the only British species, =
Excipida graminis, Berk. Br.
Fungi, No. 328, and Exc.
gram., Corda. It has a scat-
tered conceptacle, closed at
first, and subsequently widely
opened, forming a disk covered
with white spores of a peculiar
form, abruptly produced into
filaments at each end (fig.
178).

BIBL. Berk, and Broome,
Ann. N. H. 2 ser. v. 456;
Le>eille, Ann. Sc. Nat. 3 ser.

V.274; Corda, Icon. Fung.lU. Dinemasporium
pi. 6. fiff. 79 gramineum.

DINEMOU'RA, Latr.-A **S*^'
genus of Crustacea, belonging
to the order Siphonostoma and family Pan-
daridae.

Char. Lamellar elytriform appendages
covering the thorax, only one pair. First
three pairs of legs setiferous ; the posterior
foliaceous and membranous.

D. alata and D. Lamnne have both been
found upon the Beaumaris Shark (Lanma
monensis).

BIBL. Baird, Brit. Entomostr. 282.

DINENY.MTHA, Leidy.— A genus of
Holotrichous Infusoria.

Free, elongate, flexible, ciliated all
over.

D. gracilis, in the intestines of white ants.
(Kent, Inf. 555.)

DINOBRYI'NA, Ehr.— A family of
Flagellate Infusoria.

Char. Bodies variable in form, with two
flagella, one short, one long ; contained in
urceolate capsules, which are either single,
or aggregated into a branched zoary
from the new capsules remaining adherent
by their bases to the summits or the bases
of the preceding : the result of multiplica-

tion by gemmation ; freshwater. (Astasiaea
with a carapace.)

Two genera, Dinobryon and Epipyxis.

In Dinobryon an interior red eye-spot is
present, but not in Epipyxis. In the former
a flagelliform filament is present ; this is
sometimes met with in the latter, but not
constantly.

BIBL. Ehr. Inf. 122; Duj. Inf. 320.

DINOB'RYON, Ehr.-A genus of In-
fusoria, of the family Dinobryiua.

Char. Carapaces urceolate, united in the
form of a branched polypidom.

D. sertularia, E. (PI. 30. tig. 41X Cara-
paces sessile or subsessile, slightly constric-
ted near the somewhat expanded and ex-
cised end ; length of zoary 1-144 to 1-120".
of bodies 1-570".

Hermann and Archer point out that the
bodies become encysted at the mouth of the
capsules, forming Chlamydomonas - like
organisms.

Bodies yellow or green, with a red eye-
spot in front.

D. sociale, E. Carapace conical, truncate.

D. gracile, E. Carapace slightly con-
stricted in the middle.

D. petiolatum, D. (PI. 30. fig. 42). Ca-
rapaces with long stalks, bodies green j
length of the polypidom 1-100", of a cara-
pace 1-1420".

BIBL. Ehr. In/us. 124, and Berl. Ber.
1840, 199 ; Duj. Inf. 321; Archer, Qu. Mic.
Jn. 1866, 123 ; Kent, Inf. 409.

DINO'CHARIS, Ehr.— A genus of Ro-
tatoria, of the family Euchlamdota.

Char. A single cervical eye; foot forked;
carapace closed beneath, and without teeth
at the ends.

Jaws with one (or two?) teeth each.
Aquatic. Two horns at the base of the foot.

D. tetractis (PI. 43. fig. 23; fig. 24, teeth).
Carapace acutely triangular, two horns at the
base of the foot, and two toes; length 1-120".

Two other species.

BIBL. Ehr. Infus. 471.

DINO'PHYSIS, Ehr. -A genus of Fla-
gellate Infusoria, of the family Peridinaea ;
marine.

Char. Free, single ; carapace membranous,
urceolate, with a transverse ciliated furrow;
and a median plicate crest ; no eye-spot.

Form, that of Vaginicola ; nature, that of
Pendinium. The transverse furrow is close
to the truncated anterior end ; and from this
furrow there extends down the body a folded
crest or fringe, like that of Sientor, except
that it is a part of the carapace. A crown of

DIOPHRYS.

[ 265 ]

DIPLODONTUS.

cilia exists around the neck, and a longer
flagelliform filament. Carapace punctate.

J}. norwefftca; length 1-420".

Eleven species, Kent.

The species are found in sea-water with
luminous animals; probably themselves
luminous.

BIBL. Ehr. Berl. Abh. 1839, 125, 151 ;
Kent, Inf. 458.

DIO'PHRYS, Duj.— A genus of Infuso-
ria, of the family Plcesconina.

Char. Body of irregular discoidal form,
thick, concave above and convex beneath,
with five large vibratile cilia at the ante-
rior, and four or five very long geniculate
setee near the posterior end. Marine.

D. marina (PI. 30. fig. 43 : «, under view ;
b, side view). Body oval, with a longitudi-
nal excavation ; length 1-580".

BIBL. Duj. Inf. 445; Clap. & Lachm.
Inf. 406.

DIORITE. See ROCKS.

DIOSAC'CUS, Boeck.— A genus of Cope-
poda (Entomostraca.)

One species ; marine.

BIBL. Brady, Copep., Ray Soc. ii. 68.

DIPHA'SIA, Agassiz. — A genus of ma-
rine Hydroid Zoophytes, family Sertula-
riidse = Sertularia, pt. ; comprising the spe-
cies with the ovigerous vesicles cleft at
the margin. 7 species.

BIBL. Hincks, Brit. Zooph. p. 244.

DIPHYSCIA'CE JE.— A family of oper-
culate Acrocarpous Mosses, having a cap-
sule of very curious structure. The leaves
are of two kinds, the cauline tongue-shaped,
composed of perfectly Pottioid, densely
hexagonal, parenchymatous cells filled with
chlorophyll; the perichretial leaves much
protruded, exceeding the cauline, composed
of cells ultimately destitute of chlorophyll,
therefore of looser texture. Capsule very
large, oblique, gibbous, somewhat like that
of Buxbaumia. Inflorescence monoecious.
British genus :

DIPHYS'CIUM, Mohr.— Calyptra coni-
cal, covering the operculum. Peristome
simple, internal, resembling that of Bux-
baumia, surrounded at the base by a large
multiplex, soluble annulus.

BIBL. Wilson, Bnjol. Brit. 200; Berke-
ley, Hantib. 214.

DIPLA'SIUM, Presl.— A genus of As-
plenieae (Polypodioid Ferns). Exotic.

DI'PLAX, Gosse.— A genus of Rotato-
ria, of the family Euchlanidota.

Char. Those of Salpina, except that the
eye is wanting, and the carapace (which, as

in that genus, is cleft down the back) is
destitute of spines both in front and behind ;
foot and toes long and slender.

Forms a connecting link between Salpina
and Dinocharis.

D. compressa. Carapace in side view
forming nearly a parallelogram, greatly com-
pressed ; length 1-176" ; freshwater.

D. trigona. Carapace trilateral ; surface
delicately punctured ; length 1-160" ; fresh-
water.

BIBL. Gosse, Ann. N. H. 1851, viii. 201.

DIPLOCO'LON, Nag.— A doubtful ge-
nus of Scytonemaceous Algss.

D. Heppii. On calcareous rocks ; Ger-
many.

BIBL. Nageli, Nov. Act. 1857; Raben-
horst, Fl Alg. ii. 246 (fig.).

DIPLO 'DI A, Fr.— A genus of Sph^erone-
mei (Stylosporous Fungi), usually growing
upon dead twigs &c., bursting through the
epidermis. Numerous species have been
described as British by Mr. Berkeley ; but
the resemblance of many to various Sphteria
is remarked by him, and Tulasne states that
they are only stylosporous forms of species
belonging to that genus or its allies.

BIBL. Berk. Ann. N. H. vi. 365, pi. 11 ;
1850, v. 371 ; xiii. p. 459 ; Hook .Jn. Bot.
iii. 320, v. 40; Leveille, Ann. So. Nat.

3 ser. v. 290 ; Tulasne, ibid. xx. 136 ; ibid.

4 s6r. v. 115.

DIPLODON'TUS, Duges.— A genus of
Arachnida, of the order Acarina, and family
Hydrachnea.

Char. Mandibles terminated by a straight,
acute, and immoveable tooth, to which is
opposed a moveable hook or claw; palpi
shortish, with the fourth joint longest and
terminated by a point as long as the fifth
joint; coxae not very broad, in four separate
groups, the posterior of which are semi-
divergent; a bivalve, granulated, heart-
shaped genital plate, the apex directed for-
wards.

D. scapularis (PI. 6. fig. 30 : fig. «, labium
with a palp, under view; 5, a separate
mandible more magnified than a}. Eyes
very small, but projecting, wide apart, placed
at the anterior rounded angles of the body,
blackish and reniform, arising from the
fusion of two stemmata. Anterior half of
the body black, speckled with a few red
spots ; posterior half scarlet, but divided by
a median longitudinal black band. Length
of female 1-10" ; male l-3rd or l-4th the
size of the female.

D. jilipes. Palpi much curved down-

DIPLOMASTIX.

[ 266 ]

DISCOMYCETES.

wards, but little visible from above. Body
elliptical, depressed, bright red, sometimes
marbled with dark brown spots, from the
digestive organs being visible through the
integument. Eyes four, at the very anterior
margin, so best seen from beneath. Inte-
gument finely granular, without hairs. Legs
red. Length 1-25".

D. mendax. Two clear longitudinal rays
at the fore part of the body.

BIBL. Duges, Ann. Sc. Nat. 2 ser. i. 148.

DIPLOMAS'TIX, Kent.— A genus of
Flagellate Infusoria.

Char. Ovate, free, colourless, variable;
flagella 2, one vibratile, the other trailing ;
mouth distinct.

Three species ; salt and fresh water.

BIBL. Kent, Inf. 431.

DIPLO'MITA, Kent. — A genus of Fla-
gellate Infusoria.

Char. Solitary, ovate, attached by a re-
tractile filament to the base of a stalked
horny lorica, flagella two, alike j eye-spot
sometimes present ; no mouth.

D. sociahs. Brownish, length 1-1600" j
pond-water.

BIBL. Kent, Inf. 259.

DIPLONE'IS, Ebr. = Navicula with the
valves constricted in the middle.

DIPLOZO'ON, Nordm.— A genus of
Trematode Entozoa.

Char. Body of individuals soft, elongated
and flattened; united in pairs by their fusion
near the middle, thus resembling an X ;
each body terminated posteriorly by a trans-
verse, oval, or almost quadrilateral expan-
sion, furnished with four suctorial disks.
Mouth terminal, anterior, accompanied by
two oblong suctorial disks.

D.paradoxum, the double animal. Found
upon the gills of freshwater fishes, as the
carp, the roach, the bream, &c. Length
1-6 to 1-5". or twice this length.

The separate individuals (Diporpa, Du-
jardin) are smaller than those in a state of
conjugation (length 1-100 to 1-45"), and
contain no trace of reproductive organs.
Ova formed in each individual after the
conjugation; they are yellow, with the
shell narrowed and prolonged into a fila-
mentous spiral or coil.

BIBL. Nordmann, Mikr. Beit. 1832, i.
56; Ann. Sc. Nat. 1833, xxx. ; Ehrenberg,
Wiegmanrfs Archiv, 1835, ii. 128 ; Mayer,
An.d.Entoz. 23;Siebold, Sieb. u. Koll. Zeits.
iii. 62; Vogt, Mutter's Archiv, 1841,33.

DIPODI'NA, Ehr.— A genus of Rotato-
ria. Differs from Notommata by a particu-

lar constriction of its tarsal nippers or toes.
At Wismar. (Pritchard, Inf. 713.)

DIPOR'ULA, Hincks.— A genus of
Cheilostomatous Polyzoa.

D. verrucosa ; Cornwall. (Hincks,P<%zo«,
220.)

DIP'TERA.— The seventh order of IN-
SECTS, containing the " flies," &c.

DIRI'NA, Fr. — A genus ofLichenaceoua
Lichens, tribe Lecanorei.

D. ceratonicB (fig. 26, p. 65).

D. repanda. Occurs in Jersey.

BIBL. Leighton, Lich. Fl. G. B. p. 226.

DISCELIA'CE^.— A family of opercu-
late Acrocarpous Mosses, of gregarious ha-
bit, very dwarf and stemless, arising from a
green prothallium spreading on the ground.
The sheathing leaves are appressed, oblong,
acuminate and nerveless, composed of cells
lax at the base and apex, rhomboidally pa-
renchymatous, destitute of chlorophyll,
fuscescent and empty. Capsule subglobose
and inclined, with a short collum, anim ate
and long-stalked. The antheridial and ar-
chegonial flowers are upon the same runner
of the prothallium. British genus :

DISCE'LIUM, Brid.— Calyptra longish,
very narrow, split almost to the summit,
wider in the middle, with the margin invo-
lute on each side at the base. Peristome
simple, of sixteen lanceolate teeth, fissile
in the middle, trabeculate, striate, cartila-
ginous, reddish or orange.

BIBL. Wilson, Bryot. Brit. 286 ; Berke-
ley, Handb. 167.

DISCEL'LA, Berk. andBr.— A genus of
Sphseronemei (Stylosporous Fungi), forming
scattered, disk-like, dark spots upon twigs ;
at first covered by the epidermis, which
afterwards splits and separates. Five spe-
cies are described, occurring on the willow,
lime, plane, and elder.

BIBL. Berk, and Broome, Ann. N. H.
2 ser. v. 376, pi. 12. fig. 8 ; Berkeley, Outl.
322.

DISCOCEPH'ALUS, E.— A genus of
Infusoria, of the family Euplota.

Char. Head distinct from the body; hooks
present, but neither styles nor teeth.

D. rotatorius (PL 30. fig. 44). Hyaline,
flat, rounded at each end ; head narrower
than the body; length 1-380". Red Sea.
Imperfectly examined.

BIBL. Ehr. Infus. p. 375.

DISCOMYCE'TES.— The name of one
of the families of Fungi under Fries's clas-
sification, including the HELVELLACEI and
PHACIDIACEI of the ASCOMYCETES.

DISCOPLEA.

[ 267 ]

DISTICHIUM.

DISCOPLE'A, Ehr.— A genus of Diato-
macese, not now retained, the species being
referred to the genera Cydotetta and Coscino-
discus. Ehr. Ber. Berl. Ak. 1844, p. 197.

DISCORBI'NA, Parker and Jones.— One
of the Rotalina, having a turbinoid spire,
with vesicular chambers, opening one into
another by slit-like apertures, which are
usually tented over by a succession of um-
bilical flaps, forming a star-like ornament
(see ASTERIGEBJNA). The shell is usually
coarsely, sometimes finely, and occasionally
partially porous. Fossil and recent. D.
rosacea (PI. 24. fig. 7 a, b) is a neat variety
of D. turbo.

BIBL. Carpenter, Introd. For am. 203.
DISCO'SIA, Libert. — A genus of Sphse-
ronemei (Stylosporous Fungi), probably re-
lated to some of the Sphceria, as stylospo-
rous forms. The species have been described
under various names ; and the genus Phlyc-
tidium of Notaris is synonymous with it.
The British species recorded seem to have
been greatly confused by different writers ;
for Discosia alnea. Libert, found on the
leaves of alder and beech , = Spharia arto-
creas, Tode, Xylomafagineum, Pers., Phlyc-
tidium nitidum, Wallr., Ph. clypeatum, No-
taris, and, from its name, we conclude also
Dothidea alnea, Pers. of Hook. Brit Flor.,
with its synonyms. Fries, in his Summa
Veget., gives 2). artocreas, alnea, and cly-
peata as three distinct species.

BIBL. Leveille, Ann. Sc. Nat. 3 ser. v.
286 ; Fries, Sum. Veget. 423 ; Fresenius,
Beitr. z. Mycol. Heft i. 66, pi. 8 ; De No-
taris, Mem. Accad. Torino, 1849, 2 ser. x. ;
Berk., Hook. Br. Fl. 278, 288.

DISCOSIRA, Rab.— A genus of Diato-
mace£e.

Char. Frustules disk-shaped, concate-
nate ; valves nearly plane, with curved
costse ; margin denticulate ; centre deli-
cately punctate.
D. sulcata. Italy.

BIBL. Rabenhorst, Flor. Alg. i. p. 36.
DISEL'MIS, Duj. = CHLAMLDOMONAS,
Ehr. ( Chi. pulviseulus, ¥j.=Diselmisviridis,
D. ; PI. 7. fig. 2 b, c. ; PI. 30. group 30).
See PROTOCOCCUS.

Dujardin describes a marine species, D.
marina. Body almost globular, obtuse and
rounded in front, granular within, and (from
generic characters) with a non-contractile
tegument and two similar cilia.

"lie adds to this genus D. Dunalii=Mo-
nas Dunalii, Joly, giving rise to the red
colour of the reservoirs of the salt-works oi

the Mediterranean ; oval or oblong, often
constricted in the middle ; colourless when
young, greenish when older, red when
adult ; no eye-spot.

Probably marine Algae.
BIBL. Dujardiu, Inf. 340; Joly, Hist,
tfun Petit Crustace $c. 1840.

DISIPHO'NIA, Ehr.— D. australis (PI.
51. fig. \$) = Diatomella, pt.

DISO'MA, Ehr.— A genus of Infusoria,
of the family Enchelia.

Char. Body double, not ciliated ; mouth
without teeth, ciliated and truncated ( = En-
chelys with a double body).

I), vacillans (PI. 30. fig. 45). Segments
clavate, filiform ; hyaline and narrowed at
the anterior end; length 1-380 to 1-288".
In the Red Sea.

BIBL. Ehr. In/us. 302.
DIS'SODON, Grev. and Arnott.— A ge-
nus of Splachnacese (Acrocarpous opercu-
late Mosses), including some Splachna of
authors and a Cyrtodon.

BIBL. Wilson, Bry. Brit. 295 ; Berkeley,
Handb. 163.

"DISTEM'MA, Ehr.— A genus of Rota-
toria, of the family Hydatinsea.

Char. Eves two, cervical ; foot forked.
D. forfcula (PI. 43. fig. 25 ; fig. 26, teeth).
Body cylindrico-conical ; eyes red ; toes
strong, recurved, toothed at the base; fr.
water: length 1-120".

Three other species, two of which are
freshwater, and one marine. In the latter,
D. marina, the cervical eye-spots are co-
lourless ; if these do not really represent
eyes, this species must be referred to the
genus Pleurotrocha.

BIBL. Ehr. Infus. p. 449.
DISTIOHIA 'CE^E.— A family of bpercu-
late Acrocarpous (terminal-fruited) Mosses,
of csespitose nabit ; the stem increasing to-
wards the point, simple or branched ; the
leaves with a dorsal keel-like nerve, equi-
tant-concave, densely imbricatively overlap-
ping, parenchvmatously areolated. Cells mi-
nute, with thick walls, somewhat papillose,
very densely packed, squarish. Capsules
oval, equal. British genus :

DISTIC'HIUM, Br. and Schimper.-Ca-
lyptra dimidiate. Capsule annulate. Peri-
stome simple, with sixteen equidistant teeth,
free at the base, once or several times slit
from the base to the apex, trabeculate, deep
purple, homogeneous, smooth or rough. In-
florescence monoecious.

BIBL. Wilson. Bry. Brit. p. 104 ; Berke-
ley, Handb. p. 266.

DISTIGMA.

[ 268 ]

DOCIDIUM.

DISTIG'MA, Ehr.— A genus of Infuso-
ria, of the family Astasiaea.

Char. Unattached, two blackish eye-
spots.

Flagellif orm filaments two, one long, one
short ; motion similar to that of a leech.
Body variable in form ; freshwater.

D. proteus (PI. 30. fig. 46 a). Body
hyaline, obtuse at the ends, alternately
contracted or expanded from side to side ;
eye-spots distinct ; length 1-570 to 1-430".

D. viride (PI. 30. fig. 46 b). Body filled
with green granules, alternately contracted
and expanded ; eye-spots distinct ; length
1-570".

Two other species ; one yellow, the other
colourless.

BIBL. Ehr. In/us. 116; Kent, Inf. 418.

DISTOMA, (jaertn.— A genus of Mol-
lusca, of the order Tunicata, and family
Botryllidse.

Distinguished by the sessile, semicarti-
laginous, polymorphous mass ; the numerous
circular systems j the individuals in one or
two rows at unequal distances from a com-
mon centre, with thorax and stalked abdo-
men; and the branchial and anal orifices
six-rayed. On marine Algse (Fucus

D. rubi-um (PI. 36. fig. 23). Mass red

. g.

; 5"

individuals yellowish; 5" in diameter,^
thick.

D. variolosum. Reddish- or yellowish-
white ; bodies orange-red.

BIBL. Forbes and Hanley, Br. Moll. i.
18.

DISTOMA, Zeder, or Distomum. — A
genus of Entozoa, of the order Sterelmintha,
and family Trematoda.

Char. Body soft, depressed or cylindrical,
more or less elongated, not jointed, brown j
furnished with two distinct suckers — one
anterior, terminal, and containing the
mouth, the other situated on the ventral
surface between the former and the middle
of the body.

Species very numerous; Dujardin de-
scribes 164 ; most common in birds and
fishes, generally inhabiting the alimentary-
canal. Each Distoma has its separate Cer-
caria, which live in as many distinct
animals.

D. hepaticum (the fluke) occurs in the
gall-bladder and hepatic ducts of sheep
when affected with the ' rot ' ; it occurs also
in the horse, the ox, the goat, the hare, the
stag, and in man. The intestine is two-
branched, and the branches ramified.
Length 4-5 to 1}".

D. hepaticum is of special interest, on ac-
count of the immense destruction it causes
of sheep. When the young Distoma leaves
the ovum, it resembles an obconical cilia-
ted Infusorium, with a short terminal pro-
boscis ; the cilia are subsequently cast off,
and a sporocyst or Redia is formed, which
attaches itself to Mollusca, and in which
numerous Cercarice are then produced.
These when liberated, swim in water, and
are swallowed by sheep, or the mollusca
containing them are eaten with the grass ;
and so the young Distomata enter the ali-
mentary canal, to take up their final abode
in the biliary ducts.

D. lanceolatum has the intestine once
branched, then simple; it occurs in the
liver of man, the ox, the sheep, the pig £c.

D. (Bilharzia] heematobia, the African
Trematode, has the body vermiform ; the
male £", the female 1" long. It is found
in the bloodvessels of man in Egypt, -Mau-
ritius, South Africa, &c.

D. sinensis occurs in the liver of the
Chinese.

Some of the species are microscopic.

BIBL. Dujardin, Helminth. 381 ; Bene-
den, Ann. Sc. Nat. 3 se"r. Zool. xvii. ; Cob-
bold, Parasites, 1879, xiv. ; Bowles, Sheep-
rot ; Times (remedy) Apr. 10, 1881 ; Ann.
N. H. 1880, vi. 405 ; Sommer, Anat. 1880.

DIT'IOLA.— A genus of Tremellini
(Basidiomycetous Fungi) consisting of
saucer-shaped margined gelatinous Fungi,
with a discoid hymenium, which is at first
veiled. Ditiola radicata occurs rarely in
this country on decayed firwood. D. nuda,
B. and Br., is considered by Tulasne syno-
nymous with Dacrymyces deliquescens.

BIBL. Alb. & Schwein. pi. 8. f . 6 : Berk.
Outl p. 291.

DOOH'MIUS, Duj.— A genus of Nema-
toid Entozoa.

D. (Anchylostoma) duodenalis is filiform,
the head pointed and curved ; the mouth
with four unequal converging curved teeth;
body pointed behind in the female, blunt in
the male ; viviparous; length of male f",
of female £". Occurs in the human small
intestines, in Italy, Austria, Egypt, and
South' America, producing anaemia and
chlorosis.

D. trigonocephalus, in the dog.

D. Sangeri, in the elephant.

BIBL. Dujardin, Helm. 275 ; Cobbold,
Paras. 211 (fig.).

DOCID'IUM, Brebisson.— A genus of
Desmidiaceae.

DOCOPHORUS.

[ 269 ]

DORYPHORA.

Char. Cells single, straight, much elon-
gated, linear, sometimes attenuated towards
the ends ; constricted in the middle, ends
truncate ; segments usually inflated at the
base.

Rabenhorst includes the species in Pleu-
rotcenium.

Docidiwn, like Closterium, has the termi-
nal spaces with moving molecules ; and its
vesicles are either scattered or arranged in
a single longitudinal row.

D. truncatum (PI. 14. fig. 38). Seg-
ments three or four times as long as broad,
with a single inflation at the base ; suture
projecting on each side ; length 1-80 to

D. baculum (PI. 14. fig. 39). _ Segments
very slender, with a single conspicuous in-
flation at the base, otherwise linear ; vesi-
cles in a single series; length 1-111".

D. nodulosum. Segments four to six
times as long as broad, constricted at regu-
lar intervals so as to produce an undulated
margin; suture projecting; length 1-50".

Several other species.

BIBL. Ralfs, Desmid. 155; Pritchard,
In/us. 744 ; Rab. Fl. Alg. iii. 141 ; Hobson,
Qu. Mic. Jn. iii. 1863, 169 (Bombay).

DOCOPH'ORUS, Nitzsch— A subgenus
of Philopterus (Anoplura), distinguished by
the small moveable tooth or trabecula in
front of the antennae, and the dark lines
running from them to the occiput.

D. communis (PL 35. fig. 5). On Inses-
sores.

D. icterodes. Common on ducks and
geese.

DOLICHOSPER'MUM, Thwaites (P1.8.
fig. 6). — A genus of ISIostochaceae, allied to
Trichormus, Sph&rozyga, &c., established
by Thwaites for five British species, from
which Hassall has separated one under the
name of Coniophytum. Thwaites noticed in
this genus that the contents escaped in an
undivided mass from the elongated and
mostly cylindrical spermatic cells (spo-
ranges), which are invariably truncated at
the ends.

D. incequak, Ralfs. Filaments monili-
f orm ; ordinary cells at first quadrate, finally
orbicular ; vesicular cells large, spherical ;
sporanges linear, catenate (Ralfs,^4/m. N.H.
2 ser. v. pi. 9. fig. 1). Forming extensive
strata, composed of thick gelatinous masses
of a deep green colour, on boggy pools ;
filaments consisting of 100 to 200 cells.

D. Ralfsii (Kiitziug). Filaments moni-
lit'orm : ^ordinary cells spherical ; vesicular

cells elliptic; sporanges elliptic or cylin-
drical, one or two in each series. Ralfs, I. c.
pi. 9. fig. 2 ; Spharozyga Ralfsii, Thwaites,
Harvey's Algee, 2 ed. 233. Cylindrospermum
Ralfsii, Kiitzing, Tab. Phycol i. pi. 98. fig.
7. Forming extensive strata of a velvety
rich dark green colour, sometimes verging
towards seruginous green, on rivulets and
in bogs.

D. Smithii, Thwaites. Filaments straight,
each included in a definite gelatinous
sheath; ordinary cells subspherical, com-
pressed, about as long as wide ; vesicular
cells subspherical, somewhat barrel-shaped,
half as wide again as the ordinary cells,
puncta very distinct; sporanges cylindrical,
very unequal in length, and with the ends
rounded and somewhat truncated. Ralfs,
I. c. pi. 9. fig. 4. Freshwater boggy pools.

D. Thwaitesii, Ralfs. Filaments straight,
or nearly so ; ordinary cells quadrate ; vesi-
cular cells oblong, subquadrate, puncta very
distinct; sporanges numerous, cylindrical,
with truncated ends, very variable in length
(Ralfs, 1. c. pi. 9. fig. 5). Spharozyga Thw.
Harvey, Br. Algce, 2. 232. Freshwater or
brackish pools. (D. Thompsoni, Ralfs, see
CONIOPHYTUM.)

DOMOP'ORA, D'Orb.— A genus of Cy-
clostomatous Polyzoa,= Tubulipora, pt.,
Johnstone.

2 species; deep water. (Hincks, Pol 481.)

DONKIN'IA, Ralfs.— A genus of Diato-
macese, = Amphiprora with decussating
striae, but without alas to the valves.

Pritchard describes 7 species. Raben-
horst describes 4 European, and enumerates
12 extra-European species.

BIBL. Pritchard, In/us. 920; Rabenh.
Flor. Alg. i. 242.

DOO'DIA, Brown.— A genus of Blech-
nese (Polypodiaceous Ferns). Exotic.

DORIP'YGUS, Brady.— A genus of
Copepodous Entomostraca.

Four species ; inhabitants of the branchial
sacs of simple Ascidians. (Brady, Copep.,
Ray Soc. i. 132.)

DORYPH'ORA, Kiitz. — A genus of
Diatomaceae.

Char. Frustules single, stalked; valves
orbicular - lanceolate or broadly elliptical,
with a median longitudinal line, but no
nodules. Marine.

The valves are furnished with transverse
or slightly radiating rows of dots.

D. amphiceros, K. (PI. 16. fig. 29 : a, side
view of frustule ; b} front view ; c, prepared
valve.) Valves orbicular-lanceolate or

DORYPIIORA.

[ 270 ]

DRAPARNALDIA.

broadly elliptical, ends produced ; length
1-500 to 1-800".

D. Boeckii, S. (Cocconema JB., K.).
Valves elongate-lanceolate, ends somewhat
obtuse; length 1-144". This species appears
to have a median and terminal nodules.

BIBL. Kiitzing, Bacill 74, Sp. Alg. 50 ;
Smith, Diatom, i. 77; Rabenhorst, Fl. Alg.
i. 126 (Raphoneis\

DORYPH'ORA, Illiger.— A genus of
Subpentamerous (Tetrainerous, Latr.)
Coleoptera, fam. Chrysomelidse.

The very numerous species are found in
equinoctial America. The thorax or me-
sosternum is armed with a long point, pro-
jected forwards.

I), decemlineata (fig. 178*) is the Colorado

Fig. 178*.

Doryphora decemlineata. a, natural size ; b, eggs;
e, larva.

potato-beetle. It is of an orange-yellow
colour, each elytrum being marked with 5
longitudinal, dark rough-edged strife. The
eggs are yellow, and attached to the under
side of the leaves of the potato, to which
plant the hatched larvae have proved so ex-
tremely destructive in America, as to have
annihilated entire crops. The beetle has
been brought over to this country by ship,
but has fortunately not become diffused and
naturalized.

An Order in Council prohibits the keep-
ing of these beetles alive, under a severe
penalty.

DOTHID'EA, Fries.— A genus of Sphse-
riacei (Ascomycetous Fungi), often growing
upon leaves. * Distinguished from ObfaerM
and the more closely allied genera by the
asci being contained in cavities in the
stroma, without any distinct perithecium.
Numerous species are described as British
by Berkeley, some of which are now placed
under other genera by himself and Fries :
thus D. Geranii, Robertiana, Ranunculi, Po-
tentillce and Akhemillce of the Brit. Flora,

and D. Chcetomium, Kze., are species of
STIGMATEA in the Summa Veg. ; D. alnea
is removed to DISCOSIA, and D. pyrenophora
and sphceroides are placed under DOTHIORA,
Fries, a stylosporous form. The whole of
these plants require further study, since it is
probable that they are really connected
with the Sphaeronemei or Melanconiei ; for
Berkeley's observations go to show that
Asteroma Ulmi is a form of Dothidea Ulmi,
while Tulasne has found upon Dothidea
Ribesii spores or sperniatia like those of
Xylari(S;oih&TS in excavated cavities having
the character of the spores of Septoria,
while in ordinary cases the surface is cov-
ered with conceptacles filled with eight-
spored asci.

BIBL. Berk. Br. Fl ii. pt. 2. 285; Ann.
N. H. vi. 364; Berk, and Br. Ann. N. H.
2 ser. ix. 385 ; Fries, Summa Veget. 386,
418 & 421 ; Corda, Ic. Fung. iv. 119; Tu-
lasne, Ann. So. Nat. 4 se*r. v. 118.

DOTHIORA, Fries. See DOTHIDEA.

DOXOCOC'CUS, Ehr.— A genus of In-
fusoria, of the family Monadina.

Char. No tail; no eye-spot; motion
that of an irregular kind of rolling-over.

D. ruber (PI. 30. fig. 47 a, after Ehr.).
Body globose, brick-red, more or less
opaque ; breadth 1-1728"; freshwater.

This organism is almost beyond doubt the
same as that represented in PL 30. fig. 24,
d&n&f(nobis), i. e. a form of Trachelomonas
volvocina (TRACHELOMONAS). This was
suspected by Ehrenberg.

D. milvisadus, E. (PI. 30. fig. 47 b)} is
probably an early stage of the same.

The other two species — D. globulus, sub-
globose or ovate, hyaline, marine, breadth
1-864"; and D. in<pqualis, subglobose, un-
equal, hyaline, speckled with green ; fresh-
water; breadth 1-2400" — are probably
Algae, or their spores.

BIBL. Ehr. Infus.y. 28.

DRAPARNA'L'DIA,Bory.— A genus of
Chaetophoraceae (Confervoid Algae), espe-
cially distinguished (as limited here in ac-
cordance with Kiitzing) by the filaments
being composed of an axis of cells of much
greater diameter than that of the tufted cells
forming the branches (fig. 179). The spe-
cies placed here by Hassall and others, de-
void of this character, will be found under
STIGEOCLONIUM. The green contents of
the cells form a broad band in the middle
of the cell. These plants are propagated by
4- ciliated zoospores, formed from the con-
tents of the cells of the branches (fig. 180) ;

DRAPARNALDIA.

[ 271 ]

DUDRESNAIA.

and by resting-spores formed in the same
situation and set free by the solution of the
walls.

Fig. 179.

Fig. 180.

Draparnaldia glomerata.

Fig. 179. Portion of a filament. Magnified 200
diams.

Fig. 180. Portion of a branch discharging zoospores
from its cells. Magn. 400 diams.

D. glomerata , Ag. (fig. 179). Principal
filament about 1-800" in diameter, irregu-
larly branched ; ramelli 1-2400 to 1-3000",
in ovate tufts, generally alternate, and pa-
tent. Hassall, Alg. pi. 13. 1 j Engl. Hot.
1746 ; Vauch. Conferves, pi. 12. fig. 1. Com-
mon in streams and wells.

D. plumosa, Ag. Principal filaments
somewhat pinnately branched, size about
the same as the preceding ramelli, in linear-
lanceolate tufts, mostly approximated to the
axis (Vauch. pi. 11. fig. 2; Kiitzing refers
Hassall's plumosa, 1. c. pi. 12. fig. 1, to D.
opposita, Ag. as doubtful). Common in
streams and wells.

D. repetita, Hass. Principal filaments
composed of repeated series of cells, each
series consisting of five or six cells, diminish-
ing in size from the lowest to the highest,
the series adjoining each other obliquely ;
tufts of ramelli dense, alternate. Hass. I. c.
pi. 12. fig. 2. Rare.

See STIGEOCLONIUM.

BIBL. Bory, Ann. Museum, xii. ; Vau-
cher (as Batracliospermuni), Conferves d'Eau
douce ; Link (as Charospermum),Hor. Phys.
iii. j Hassall, Algce, 118 ; Decaisne, Ann.
Sc. Nat. 2 ser. xvii. 314 ; Thuret,«. 3 ser.

xiv. 15; Currey, Qu. Mic. Jn. vi. 207,
pi. 9; Hicks, ibid. 1869,383; Rabenhorst,
Fl. Alg. iii. 381.

DREPANOS'IPHON, Koch.— A genus
of Aphidse.

D. platanoides, and D. acerina, on the
sycamore. (Buckton, Aphid., Ray Soc. i.
182.)

DRI'MYS, Forst.— A genus of Magno-
liacese (Dicotyledonous Plants), remarkable
for the microscopic structure of the wood.
See WINTERED.

DRY ROT.— A peculiar decay in wood,
caused either by the presence of Fungi, as
Merulius lacrymans and Thelephorapateana,
or by a chemical process known under the
name of Eremacausis or gradual combustion.
Many remedies have beeen proposed ; sul-
phate of copper, corrosive sublimate and
creosote, especially the latter, are amongst
the most approved. In domestic architec-
ture, a free circulation of air and exclusion
of moisture are essential.

DRYMOGLOS'SUM, Presl.— A genus
of Grammitideae (Polypodiaceous Ferns).
D. cornosum, exotic.

DUCTS.— A term applied in structural
botany to those forms of ~Fig. 181.
the so-called vascular tissue
which consist of long tubes
constructed out of perpendi-
cular rows of cells, which are
thrown into one by the ab-
sorption of their adjoining
ends. Ducts are thus easily
distinguished from vessels,
which taper off to closed ends,
by the constrictions upon the
walls of the tubes, indicating
the junctions of the compo-
nent cells (tig. 181). SeeDoto5dductfrom
TISSUES, VEGETABLE; and the Melon.

VESSELS. Magn. 250 diams.

DUDRESNAI'A, Bonnem.— A genus of
Cryptonemiaceae (Florideous Algse), con-
taining two minute British species, with
delicate, branched, filiform fronds, a few
inches high, of rose-red or reddish-brown
colour. D. coccinea, which is a very rare
plant, and seldom found except on the
south coasts of England and Ireland, and
D. Hudsoni) a not uncommon sea-weed,
present very elegant microscopic structure,
the fronds being composed of a central
cellular axis, clothed with tufts of delicate,
dichotomous, moniliform filaments, stand-
ing perpendicularly upon it. The fructify-
ing process in this genus is very complicated.

DUFOUREA.

[ 272 ]

DYTISCUS.

BIBL. Harvey, Brit. Alg. 154, pi. 21 C ;
Phyc. Brit. pis. 110, 244; Sachs, Bot. 294.

DUFOU'REA, Ach.— A genus of Li-
chens. D. madreporiformis occurs in Swit-
zerland and Germany.

DUMON'TIAjLamx.— A genus of Cryp-
tonemiacese (Florideous Algae), containing
one British species, D.filiformis, having a
delicate tubular frond, of yellowish,greenish,
or purple colour, of variable length and dia-
meter, with numerous filiform branches,
which are long on short fronds, and short on
long fronds ; growing commonly on rocks &c.
between tide-marks. The wall of the tube is
composed of a double layer of tissue, the
outer of roundish cells, the inner of longish
cells forming filamentous rows. The spores
are attached in clusters to the internal wall
of the tube (which is filled up with gela-
tinous substance), while the tetraspores are
found among the surface-cells.

BIBL. Harvey, Brit. Alg. 147, pi. 20 a ;
Phyc. Brit. pi. 59 j Greville, Alg. Brit. pi.

DYEING. See STAINING.

D YSPONTI CIS, Thorell.— A genus of Co-
pepodous Entomostraca.

D. striatus, in dredgings. (Brady, Copep.,
Hay Soc. iii. 65.)

DYSTE'RIA, Huxley.— A genus of
Hypotrichous Infusoria, fam. Ervilina.
Distinguished by the valves of the carapace
being united behind, but below only. Ma-
rine ; five species.

BIBL. Huxley, Qu. M. Jn. 1857, 78;
01. & Lachm. Inf. 284.

DYSTERI'NA,C1. &Lachm. = .Eh»7zwa.

DYTIS'CUS, Linn., or Dy'ticus, a genus
of Coleopterous Insects of the family Dy-
tiscidae.

Characters of the family : antennae long
and slender ; external lobe of maxillae arti-
culated ; anterior pair of legs shorter than
the posterior pairs, which are flattened and
fringed with hairs. Freshwater.

The genus Dytiscus is characterized by
the first three joints of the anterior tarsi in
the male being very large, and expanded
into a patella or shield; the didactyle claws;
and the maxillary palpi having the second
and third joints of equal length.

The species of Dytiscus are of large size ;
D. marginalia is common in ponds and pools.

The head is well adapted for the display
of the trophi, or organs of the mouth.
Labrum transverse; mandibles short and
robust, with a strong internal tooth ; max?
illse short, flat, and ciliated internally, with

the tip acute, the outer lobe palpiform : the
true maxillary palpi about twice as long as
the maxillae ; mentuin transverse, with the
sides produced into two lobes; labium
short and square, palpi about twice its
length, and three-jointed. The structure
of the anterior tarsi in the male is very
curious (PI. 34. fig. 6 a), the three basal
joints being expanded laterally so as to
form a broad and rounded patella or shield,
convex above, and covered beneath with a
number of suckers or disks of various sizes,
some of which are stalked (fig. 6 b. a small
one). This structure enables the male to
retain his hold upon the back of the female,
the elytra of the latter being furrowed lon-
gitudinally, to aid in this effect. The three
basal joints of the tarsi of the middle pair
of legs are also flattened beneath, and co-
vered with the stalked disks.

Fig. 182.

Dytiscus latissimus. Natural size.

Full-grown larvaa about two inches in
length ; of a dark ochre or dirty brown co-
lour; the body long, subcylindrical, and
eleven-jointed ; the two terminal joints
long and conical, the sides of the* apex
fringed with hairs. Terminal segment fur-
nished with a pair of long and slender pi-
lose appendages, by means of which the
insect can suspend itself at the surface of
the water ; these are tubular, and commu-
nicate with the tracheae of the body. Head
(PI. 35. fig. 14) large, oval, or rounded, de-
pressed, and with five or six small elevated
tubercles near the anterior angles represen-
ting the eyes (fig. 14 a). Two rudimentary,
slender, seven-jointed antennae (b) are in-
serted in front of the eyes. The mouth

ECCRINA.

[ 273 ]

ECHINOCOCCUS

has no aperture ; the food, consisting of the
juices of the prey, passes through a canal
traversing the long, sickle-shaped, acute
mandibles (c). Maxillae (d) slender, cy-
lindrical, and terminated by a short lateral
spine ; the maxillary palpi (e) are of the
same thickness, arising from the tip of the
maxilla?, and seven-jointed. Labial palpi
(/) slender and four-jointed, the first and
third joints being very short.

The head of the larva, and the three pairs
of legs of the perfect insect, are commonly
mounted as microscopic objects, as are
those of other genera belonging to the fa-
mily— Acilius &c.

BIBL. Westwood, Introd. &c. i. p. 95 ;
Stephens, Brit. Beetles.

E.

ECCRI'NA, Leidy.— See ENTEROBRY-
us.

EOHINEL'LA, Acharius. — A term ap-
plied first to a group of ova of some aquatic
animal, next to a genus of Infusoria, more
recently to a genus of Diatomaceae, but now
no longer used.

ECHINOBO'TRYTJM,Corda.— A doubt-
ful genus of Torulacei (Coniomycetous Fun-
gi). E. atrum has been found in Britain,
parasitic upon a species of Pachnocybe.

BIBL. Berk, and Broome, Ann. N. H.
2 ser. v. 460 ; Corda, Icon. Fung. ii. fig. 6.

ECHINOCOC'CUS, Rud.— A supposed
genus of Entozoa, of the order Cestoidea
and family Cystica ; now shown to consist
of the larvae of T^NIA.

Char. Consisting of a vesicle of very va-
riable size, sometimes surrounded by a coat
of condensed areolar tissue, and containing
within, one or more secondary cysts ; at-
tached to the walls of these cysts, or sus-
pended in their liquid contents, are nume-
rous oblong, rounded, or oval bodies (sco-
lices), each with four suckers, and a double
crown of hooks. .

E. veterinorum, the larva of Tcenia echi-
nococcus (PL 21. figs. 1 & 2), occurs in the
liver, the cavity of the abdomen, the heart,
the voluntary muscles, and the ventricles
of the brain of man ; in the liver, lungs, &c.
of the ox, sheep, goat, ape, pig, &c. Com-
monly called hydatids. The walls of the
brood-cysts consist of numerous concentric
layers or plates, resembling those of colloid
cells or cysts. The liquid existing within

the cysts is yellowish or reddish, albumi-
nous, and frequently contains plates of cho-
lesterine, and crystals of bilifulvine (PI. 13
fig. 15) (see BILE) ; some of the latter re-
semble in form and colour those of HJEMA-
TOIDINE. The scolices appear to the naked
eye as minute, white, opaque specks, varying
in size from about the 1-300 to 1-100" in
length. They also vary greatly in form ;
when the head is retracted (fig. 1 a) they
appear more rounded than when this is
protruded (fig. 1 c, 1 d, If). The hooks
surrounding the anterior end of the body
(fig. 1 6) consist of a broadish basal portion,
an internal transverse blunt tooth, and a
curved terminal portion or claw ; they are
about the 1-1500 to 1-1000" in length. In
some of the scolices a kind of pedicle exists
at the base, by which they are attached to
the wall of the cyst (figs. 1 a and 1 c) ; some-
times two or more lines may be perceived,
running from the head towards the pedicle,
and connected in front by a transverse line
— probably representing vessels (fig. 1 c).
Interspersed through the substance of the
body are minute highly refractive corpus-
cles, containing carbonate of lime.

In the quite recent state, the scolices
have been seen swimming actively in the
liquid of the cyst ; this motion is produced
by cilia existing upon the surface of the
body. Mingled with the perfect scolices
are generally found some in which neither
hooks nor suckers are visible, and in which
the form is very irregular ; some of these
assume the natural form when treated with
acetic acid.

The scolices appear usually to be deve-
loped by gemmation from the interior of
the cysts ; but, as Kuhn long since showed,
they "are sometimes produced by external
gemmation (fig. 2) : the contents produce
a slight protrusion of a part of the wall of
the cyst; the protruded portion enlarges,
afterwards becoming constricted at its base,
at last probably separating from the parent,
to become itself a parent in the same man-
ner. The example figured in PI. 21. fig. 2
was not isolated ; there were many, con-
tained with numerous other larger cysts, of
the most varied sizes, all in one very large
parent cyst.

The Echinococci do not attain their full
development into Tcenice, unless they reach
the alimentary canal. The cysts and their
contents, including the Echinococci, some-
times undergo a kind of degeneration, be-

ECHINODERMATA.

C 274 ]

ECHINODERMATA.

coming partially converted into fatty or
calcareous matter ; or the entire contents
become amorphous and granular, the hooks
remaining longest unaltered, but finally dis-
appearing also.

See T^ENIA.

BIBL. Kuhn, Ann. Sc. Nat. 1 ser. xxix.
273; Siebold, Wiegm. Archiv, 1845, ii.
241, and Siebold und Kottiker's Zeits. iv. ;
Dujardin, Helminth. 635 j Cobbold, Paras.
112.

ECHINODER'MATA. — A Subking-
dom in the Animal Kingdom, including
the star-fishes (Asterias), the sea-hedgehogs
or sea-eggs (Echinus), the sea-slugs (Holo-
thuria), &c.

The Echinodermata are marine animals,
with a coriaceous or calcareous integument ;
alimentary canal distinct, suspended in the
cavity of the abdomen, and with either one
or two orifices ; distinct organs of circula-
tion and respiration ; sexes usually distinct,
and external generative organs never pre-
sent ; disposition of organs generally qui-
nary ; body usually radiate or globose,
sometimes cylindrical; nervous system form-
ing a ring generally surrounding the mouth
and giving off radiate branches.

A cutaneous skeleton usually exists as a
network of calcareous corpuscles (PL 45.
fig. 1), or numerous calcareous plates pretty
regularly perforated so as to form a solid
continuous network (PL 45. fig. 2). The
plates are sometimes moveable, at others
connected by sutures ; some are perforated
with larger apertures — the ambulacra! pores;
they are often furnished with calcareous ap-
pendages, tubercles, prickles, spines, hooks,
&c., some being imbedded in the leathery
integument itself. Many of these appen-
dages, as well as the calcareous corpuscles,
form beautiful microscopic objects, and
possess very remarkable analytic power
(see ECHINUS, SYNAPTA, and SHELL) ; they
are also of importance in classification.

The muscular system consists of distinct
flattened primitive fibrils and bundles, not
transversely striated. The organs of loco-
motion exist in the form of little tentacle-
like organs, the so-called feet or ambulacra.
These are very contractile hollow prolonga-
tions of the cutaneous surface, expanded at
the end, and connected by the ambulacral
pores with contractile sacs (the ambulacral
vesicles) placed on the inner surface of the
leathery or calcareous covering of the body j
they act as organs of adhesion and as
feelers.

In the Echinidea (-Ec7*mws-fanrily) and
Asteridea (Asterias- family), other curious
appendages occur, called pedicellarice (PL
45. fig. 3) ; they are met with all over the
cutaneous surface, and consist of a forcipate
or valvular apparatus, acting as organs of
prehension. The pedicellarice of the Aste-
ridea usually consist of two or three forceps-
like or two broad valvular arms, and have
hence been divided into forcipate and val-
vate pedicellarice. They are mostly without
a stalk. In the Echinidea {Echinus} they
are most numerous around the mouth, and
have been subdivided, according to their
form, into : — 1. Gemrniform, having three
short lentil-shaped arms; 2. Tridactyle,
having three long and laterally toothed
arms; and 3. Ophiocephalous, with three
spoon-shaped laterally toothed arms. These
pedicellarice contain a reticular calcareous
mass as a basis, and in Echinus are placed
upon a stalk, the lower portion of which
encloses a calcareous nucleus, whilst the
other portions are soft, extensile, and spi-
ral Iv retractile, Tha pedicellarice of Echinus,
which are partially covered with ciliated
epithelium, can seize largeror smaller bodies,
and pass them from one to the other ; so
that an object grasped by one of them situ-
ated on the posterior half of the body, or
near the anal region, can be gradually
passed on towards the mouth.

The abdominal cavity of the Echinoder-
mata is always filled with sea-water, kept
in motion by cilia covering the intestinal
canal.

A true blood-vessel system, as well as the
water-vessel or ambulacral system, is also
present, into the structure of which and
other particulars we have no space to enter.

In their youngest state, the Echinoder-
mataconsistofinfusoria-likebilateralbeings,
without organs, and swimming by means of
cilia on the surface.

BIBL. Siebold, Vergl. Anat. 74 ; Sharpey
Cycl Anat. fy Phys. ii. 30; Agassiz, Echi-
nod. viv. et foss. ; Valentin, Echinoderm ;
Forbes, Br. Starfishes; Miillerand Troschel,
Asteriden ; Miiller, Berl. Abh. 1846-1851 ;
Huxley, Ann. N. H. 1851, viii. 1 ; Gosse,
Mar. Zool. i. 54 ; V. d. Hoeven, Zool and
Suppl. (Leuckart) ; Gegenbaur, Vergl. An.
205 ; Herapath, Qu. M. J. 1865, 175 (pedi-
cellarice) ; Frey, Bedeck, wirbell. Th. ; Koren,
Arch. Scandinav. i. 166, 449 ; Norman, Ann.
N. H. 1865, xv. 98 ; Stewart, Qu. M. J.
3871 ; Nicholson, Zool. 1878, 181 ; Sladen,
Ann. N. H. 1880, vi. 101 (pedicellarice).

ECHINORHYNCHUS.

[ 275 ]

EELS,

ECHINORHYN'CHUS, Midler.— A ge-
nus of Entozoa, order Acanthocephala.

Char. Body cylindrical or sacciform,
somewhat elastic, transversely rugose, ob-
tuse at both ends ; furnished with a retrac-
tile proboscis, which is armed with from
one to sixty regular transverse rows of re-
curved spines ; sexes distinct ; no mouth.

The species, which are very numerous,
many microscopic, reside in the alimentary
canal, most commonly of fishes and reptiles,
less so in that of mammals, and still more
rarely in that of birds.

E. anthuris (PI. 21. fig. 35) is very com-
mon in newts ; E. proteus in fish.

BIBL. Dujardin, Helminth. 483 ; Leuc-
kart, Paras.

ECHI'NUS, Lam.— A genus of Echino-
dermata, of the family Echinidea.

The species are popularly known as f sea-
urchins,' or ( sea-eggs.'

The beautifully symmetrical structure of
their spines, and their curious pedicellarice,
afford favourite objects to the admirers of
nature's minute wonders. These organs are
not confined to this single genus of the
family.

See ECHINODERMATA and SHELL.

ECTINOSO'MA, Boeck.— A genus of
Copepodous Entornostraca.

Four species ; among sea- weeds. (Brady,
Copep.) Ray Soc. ii. 8.)

ECTOCARPACESE.— A family of Fu-
coidesB. Olive-coloured, articulated, fili-
form sea-weeds, with sporanges (producing
ciliated zoospores) either external, attached
to the jointed ramuli, or formed out of some
of the interstitial cells. British genera :

* Frond rigid ; each articulation composed
of numerous cells (Sphacelarieae).

Cladostephus. Ramuli whorled.
Sphacelaria. Ramuli distichous, pinna-
ted.

** Frond flaccid ; each articulation com-
posed of a single cell.

Ectocarpus. Frond branching; ramuli
scattered.

Myriotrichia. Frond unbranched; ra-
muli whorled, tipped with pellucid fibres.

BIBL. See the genera.

ECTOCAR'PUS, Lyngb.— A genus of
Ectocarpacese (Fucoid Algae), consisting of
olive or Drown sea-weeds, with fronds com-
posed of flaccid capillary filaments, growing
between tide-marks or upon other Algee.

Fig. 183.

Filaments of very simple
structure, the main axes or
branches being composed of
single rows of cells (fig. 183),
as in Cladophora. The re-
productive bodies at present
known, ciliated zoospores, are
formed in the cells of the
branches, sometimes in the
terminal cells, producing the
siliquose or elliptical (fig.
183) sporanges, and some-
times in interstitial cells, be-
yond which the branch is
prolonged into a fine filament.
In E. siliculosus the extremi-
ties of the branches are con-
verted into sporanges : the Portion of a fl-
ceU-contents first divide into g™^f ^Jg
a number of layers, while the caiTporangS.1"
part of the filament contain- Magn. 50 diams.
ing these swells up and ac-
quires the pod-like form; the layers of con-
tents are then resolved into lines of zoo-
spores piled regularly one above another.
The summit of the pod finally bursts, and
the zoospores escape. The empty sporange
exhibits fine transverse striae, as if delicate
septa existed between the layers of zoo-
spores. In E. litoralis, Harv., the fertile
cells are not terminal, but interstitial, and
form beaded rows surmounted by a hair-
like prolongation of the branch ; the zoo-
spores escape by a lateral pore. The germi-
nation of these zoospores has been observed
by Thuret. Sixteen British species (Har-
vey), some of which are common, particu-
larly the two above mentioned.

BIBL. Harvey, Mar. Alg. 58, pi. 9c;
Phyc. Brit. pis. 162, 197, &c. ; Eng. Bot.
pis. 2290, 2319, &c. ; Thuret, Ann. Sc. Nat. 3
ser. xiv. 234, pi. 24. figs. 1-7 ; Agardh, Ann.
Sc. Nat. 2 se'r. vi. 197 : Crouan, ibid. xii.
p. 248, pi. 5.

ECTOPLEU'RA, Agassiz.— A genus of
Hydroid Zoophytes, fam. Tubulariidse.

E. Dumortierii. Isle of Man, Ostend.

BIBL. Hincks, Brit. Zooph. 124.

EEL (Anguilld).—It is popularly believed
that the eel has no scales. They are, how-
ever, present, but immersed in the skin ; and
their structure is curious (SCALES of FISH).
The dried skin of the Eel, mounted in
Canada balsam, exhibits well the scales,
covered by the epidermis, and the beautiful
layer of stellate pigment-cells.

BIBL. Yarrell, Brit. Fishes, ii.

EELS, in paste (ANGULLLULA GLUTINIS).

EELS.

[ 276 ]

EL^EAGNACE^E.

EELS, in vinegar (ANGUILLULAACETI).
EGGS. — The minute ova of certain ani-
mals have always been favourite microscopic
objects on account of their curious forms, the
beautiful structure of their outer chitinous
envelope, their varied colours, and the sin-
gular lids with which some of them are
furnished. The most interesting are those
of insects : among them we may mention
the brown eggs of the puss-moth, Cerura
vinula (PI. 39. fig. 19) j of the large and
small cabbage-butterflies, Pontia brassicce
and rapes (PI. 39. fig. 21) ; of the small
tortoiseshell butterfly, Vanessa urticce ; the
angle-shades moth, Noctua or Phlogophora
meticulosa ; the common meadow brown
butterfly, Hipparchia Janira ; the brimstone
moth, Rumia cratcegata ; the water-scorpion,
Nepa ranatra ; the common cow-dung-fly,
Scatophaga stercoraria, which are very
common on cow-dung ; the bug, Cimex
lectularius (PI. 39. fig. 20), Hydrometra
stagnorum, &c.

Their surfaces exhibit markings of the
most varied forms — spines, tubercles, pits or
processes, sometimes of considerable length
(PL 21. figs. 22, 23), often arranged with
great symmetry, and frequently closely re-
sembling the cellular structure of plants in
appearance. Sometimes very delicate an-
gular spaces are mapped out upon them, the
intervals being most minutely dotted, as in
the eggs of the common blow-fly, Musca
vomitoria (PI. 34. fig. 35).

It is a genera] fact, exemplified in both
the animal and vegetable kingdom, that
unicellular, or the corresponding stages or
phases of the higher organisms, exhibit
markings of some kind upon their external
membrane or wall, as is seen in the cells
of the Desmidiaceae, the Diatomacese, the
eggs of animals, the spores and pollen-grains,
and the seeds of plants.

At certain seasons of the year, the eggs
of some aquatic animals are provided with
a very thick horny coat, as in the Entomos-
traca, Hydra, &c. These have been called
winter ova, from the notion that here was
a defence against a low temperature ; they
correspond to the resting-spores or resting-
stages of the Infusoria and Algae, some of
which were formerly included in the ani-
mal kingdom. The formation of this coat
can scarcely have any relation to tempera-
ture, either from its structure or from its
requirement in an organism which has no
heat to retain. Its presence would be per-
fectly intelligible, however, as a means of

protection from evaporation when the
pools become dry j and for this purpose its
structure is well adapted. It might also
afford ^a protection against the attacks of
predatory animals, many of which could
easily devour an ovarian ovum, while they
could not break through the horny cases of
the winter ova ; and these winter ova are
only formed when the ova are not to be
hatched soon after extrusion from the pa-
rent. The ova of those animals which are
never hatched immediately after leaving
the parent, have always a coat correspond-
ing to that of the winter ova.

The structure and development of eggs
are considered under OVUM; see also SHELL.
BIBL. See OVUM.

EHRENBERGI'NA, Reuss.— A Cassi-
duline Foraminifer with the later portion
of the shell uncoiled.

BIBL. Carpenter, Introd. Foram. 198.
ELACHISTEA, Fries. — A genus of
Myrionemaceae (Fucoid Algae). Minute
epiphytic sea-weeds, consisting of a dense
tuft of simple, articulated, olivaceous fila-
ments, from a common tubercular base
composed of a closely combined mass of
dichotomously branched filaments, growing
upon larger Fucoids, such as Fucus, Hi-
manthalia, Cystoseira, &c. The fructifica-
tion is borne in two forms — unilocular
(spores, Harvey) and multilocular sporanges
(paranemata, Harvey). The unilocular are
formed of metamorphosed terminal cells at
the ends of the dichotomous filaments; they
are long ovoid sacs, the contents of which
are ultimately converted into a vast number
of zoospores. The multilocular sporanges
arise exactly in the same place and way,
but take the form of long, slender, articu-
lated filaments, in the joints of which simi-
lar but smaller zoospores are developed.
Both forms of fructification nestle on the
surface of the tubercle of the frond, at the
base of the long simple filaments. The
zoospores of both kinds of fruit germinate ;
and these occur together in some cases (E.
attenuata], in others at different seasons of
the year. Harvey describes seven British
species ; the tufts of some are half an inch
long, of others less than a line,

BIBL. Harvey, Mar. Alg. 49, pi. 10 F ;
Pkyc. Brit. pis. 240, 260, 261, &c. ; Dillw.
Conferv. pi. 66 &c. ; Thuret, Ann. Sc. Nat.
3 s«5r. xiv. p. 236, pi. 25. figs. 1-4.

EL JEAGNA'CEJE.— A family of Dico-
tyledons, the leaves of which are usually
covered with a kind of scurf formed of very

ELAPHOMYCES.

[ 277 ] ELASTIC LIGAMENTS.

elegant microscopic scales. See HAIRS, and
HIPPOPHAE.

ELAPHOMY'CES, Nees.— A genus of
Tuberacei (Ascomycetous Fungi) consist-
ing of subterraneous truffle-like plants, with
a warty or hairy rind, not bursting sponta-
neously, but divided into little chambers
internally by intersecting plates of sporife-
rous tissue. The spores are formed in sacs
(asci) (fig. 185), from four to eight in each,
arising from branched anastomosing fila-
ments (capillitium). Three species are
found in this country : — E. anthracinus,
Vitt, in clayey ground; E. granulatus,
growing in heathy ground ; and E. muri-
catus, FT. (E. variegatus, Vitt, Tulasne),
attached to the rootlets of beeches. L. and
C. Tulasne have carefully analyzed this
genus.

BIBL. Berk. Br. Fl. ii, pt. 2. 306 ; Ann.
N. H. vi. 430, pi. 11. fig. 10 ; L. and 0. Tu-
lasne, Ann. So. Nat. 2ser. xvi.p.5,pls. 1-4;
Hypog. Fungi, 1850 ; Vittadini, Monog. Tu-
ber. App. 66, &c., pis. 3 & 4 ; Berk. & Br.
Ann. N. H. xviii. 81.

Fig. 184.

Fig. 185.

Fig. 184. Elaphomyces Mrtus. Section, nat. size.

Fig. 185. E. variegatus. Filaments of capillitium,
with asci containing spores, and also loose spores
which have escaped. Magnified 300 diameters.

ELASTIC LIGAMENTS.— These are

yellowish strong bands, consisting of elastic
or yellow fibrous tissue, with a small quan-
tity of connective tissue. They are met with
connecting the arches of the vertebrae (liga-

menta subflava), in the stylo-hyoid and in-
ternal lateral ligaments of the jaw, and the

Fig. 186.

Transverse section of the ligamentum nucb.se of an
ox, after treatment with solution of caustic soda : a,
connective tissue, appearing transparent ; 6, section of
elastic fibres. Magnified 350 diameters.

ligamentum nuchse, or <paxy-waxy,' of ani-
mals. They contain but few vessels, and
no nerves. The elastic fibres (fig. 187) are
from 1-7500 to 1-3500" in breadth, slightly
flattened (tig. 186), mixed with still finer
and some coarser elastic fibres, forming a
dense network, taking a general direction
parallel to the long axis of the spine. Be-
tween these fibres are loose undulating

Fig. 187.

Elastic fibres: a, from a human ligamentum snbfla-
Tum, with intervening connective tissue, 6. Magnified
450 diameters.

bundles of connective tissue, running paral-
lel to the elastic fibres.

BIBL. Kolliker, Mik. An. ii. 306, and

ELASTIC TISSUE.

[ 278 ]

ELASTIC TISSUE.

Gewebel. d. Mensch.-, Rollett, Strieker's
Geweb. i. 59.

ELASTIC TISSUE of animals, or yel-
low fibrous tissue, occurs in the ligamenta
subflava of the vertebrae, in the thyro-hyoid
and cricoid membranes, the vocal chords,
the trachea, forming the longitudinal elastic
bands of that tube and its branches, in the
internal lateral ligament of the jaw, the
stylo-hyoid ligament, the transversalis fas-
cia of the abdomen, the blood-vessels, and
almost everywhere mixed with the fibres
of connective tissue.

It differs from white fibrous tissue in its
elasticity and its yellow colour. But some
physiologists regard it as a variety of this.

Its elementary form is that of round or
flattened fibres, varying in size from an
almost immeasurable tenuity to that of
1-2200" or even more ; the finer ones have
been termed nuclear fibres by the Germans ;
thev are either isolated, arranged in bundles,
or branching and anastomosing (fig. 189),
sometimes undulating or spiral, at others
nearly straight. When broken, they curl
up, the ends appearing abrupt or truncated.
They are highly refractive, their edges
appearing dark, well-defined, and mostly
smooth, but sometimes toothed or serrated.
Sometimes they exhibit transverse .cracks
upon the surface.

Fig. 188.

Fig. 189.

Fig. 188. Network of elastic tissue, from the middle
coat of the pulmonary artery of the horse. Magnilied
350 diameters.

Fig. 189. Network of fine elastic fibres from the
peritoneum of a child. Magnified 350 diameters.

They are easily distinguishable from fibres
of connective tissue by the use of acetic acid,

which has little or no effect upon them ; and
this is also the case with solution of potash.
Sometimes by their anastomoses they form
fibrous networks (fig. 189), or plates perfo-
rated irregularly by holes — fenestrated
membranes (fig. 188). The fibres are also
themselves sometimes transversely perfo-
rated by irregular rounded apertures.

Chemically, elastic tissue consists of elas-
tine. It is coloured red by Millon's test,
but not by that of Pettenkofer, and does
not yield gelatine by boiling.

Elastic tissue is probably developed from
cells. In all parts of embryos where elastic
tissue occurs, peculiar fusiform or stellate
cells (fig. 190 a) with acute ends or pro-
cesses are met with, by the fusion of which
(tig. 190 b & 191) long fibres or networks
are formed, in which the spots correspond-
ing to the cells at first form dilatations with
elongated nuclei. The fibres frequently
remain in this condition, forming a modifi-
cation of the so-called nuclear fibres; or

Fig. 190.

Fig. 191.

Fig. 190. Formative cells of elastic tissue, from the
tendo Achillis : a, of a four months' embryo • b of a
seven months' foetus ; some of the cells are free 'with
one or two processes, others fused in twos and threes
Magnified 350 diameters.

Fig 191 Stellate formative cells of nuclear fibres,
from the tendo Aohillia of a newly born infant. Mae-
mfied 350 diameters.

EIASTINE.

[ 279 ]

ELYTRA.

all traces of the original composition vanish,
uniform fibres or networks alone remaining.
There is, however, great difference of opinion
among physiologists as to the development
of elastic tissue, some regarding it as arising
from fibrillation of the intercellular sub-
stance.

Elastic tissue occurs in the same situations
in all classes of the Vertebrata as in man —
also in some special localities, as in the
ligaments of the claws of the cat, the folds
of the wing-membrane, and the pulmonary
sacs of birds. In the Invertebrata, this
tissue appears to occur but rarely ; and it is
uncertain whether the elastic ligaments
existing in them, e.g. those of the mollusca,
agree anatomically and chemically with the
elastic tissue of the higher animals or not.

BIBL. Kolliker, GewebeL ; Reichert, Mutt.
Archiv, 1856, Hft. vi. 55 ; Leydig, Hist. 27 ;
Frey, Histol. 1876 (very complete litera-
ture), 246; Beale, Simple Tissues ; Rollett,
Strieker's Handb. i. 59.

ELASTINE.— The proximate chemical
principle of which elastic tissue consists.

EL'ATERS.— This name is applied to
two forms of structure occurring in the
higher Cryptogamous Plants. The elliptical
spores of the Equisetacese are furnished
with what are called elaters, viz. four elastic
filaments, attached about the middle of one
side, which are coiled once or twice round
the spore before it is discharged from the
capsule, in the position where they were
originally developed; but when the spore
is discharged, they uncoil with elasticity,
causing the spore to be jerked away. They
appear to be produced by the outer coat of
the spore splitting in spiral fissures, and
separating in ribands from the inner coat.
See EQUISETACESE.

The elaters of the Liverworts or Hepa-
ticae are of different nature ; they consist
of more or less elongated delicate mem-
branous tubes, which are closed cells, inside
which one or more elastic spiral fibres are
coiled up. They occur mixed with the
spores in the capsules of the Jungermannieae,
sometimes attached to the valves ; they
here mostly present the appearance of cy-
lindrical cellulose tubes, closed at the ends,
with a flat spiral band coiled in an open
spiral, adherent to the cell-membrane form-
ing the wall (PL 40. fig. 3d). The elaters
found among the spores of Marchantia poty-
morpha (PI. 40. figs. 36, 37) are very long,
and contain a double coil, the ends of the
two fibres coalescing into a loop at each

extremity (PL 40. fig. 37 b) ; so that the
entire fibre may be compared to a piece
of string with its ends united, and laid out
so as to represent two cords, side by side,
which are then twisted spirally round one
another. In TARGIONIA the tubes are
sometimes branched. The development of
the spiral fibres is similar to that of the
spiral fibres of vessels. See HEPATIC^.

Structures apparently analogous to these
elaters of the Hepaticaa occur in some of
the Myxogastrous Fungi, as in TRICHIA
(PL 40. fig. 390) ; while in other genera of
this family filamentous bodies occur, either
plain or obscurely marked. In Batarrea
also, one of the Puff-balls, a kind of elater
exists accompanying the spores (see TRICHO-
GASTRES). It has been stated by Schleiden
and Schacht that the elaters of these Fungi
are solid filaments with spiral ridges upon
them, or flat solid ribands twisted on their
longitudinal axis. This statement is at
variance with our observations, and is not
borne out by the drawings given by these
authors themselves. CuiTey, while also
contesting Schleiden's view, states that the
spiral line is a ridge outside a tube, — a con-
dition of things unlike any thing else we are
acquainted with in vegetables.

The elaters of Trichia require a very high
power for their elucidation, an eighth or
twelfth, with a high eyepiece, "and a good
light ; they may then be seen to consist of
tubes with spiral fibrous secondary deposits
upon the inside of their walls (PL 40. fig. 40).
See SPIRAL STRUCTURES.

BIBL. See EQUISETACE^, MARCHANTIA,
TRICHIA, and SPIRAL STRUCTURES.

ELDER. — Santiucus niger, the common
Elder tree (Caprifoliacese, Dicotyledons), is
remarkable for the great development of its
pith ; sections of this furnish very accessible
and convenient illustrations of vegetable
parenchyma.

ELLIPSOIDI'NA, Seguenza.— An egg-
shaped hyaline Foraminifer, probably Gryp-
tostegian. The adult has three concentric
chambers, one within another, touching at
their bases and kept apart at the apices by
an internal column. An irregular septal
orifice surrounds the column as it passes
through the chamber-wall. E. ellipsoides
and its varieties only are known. From
the Mid-Tertiary beds of Sicily.

BIBL. Brady, Ann. N. H. 1868, i. p. 333.

ELYTRA.— The horny anterior pair of
wings of the Coleoptera ; sometimes called
wing-covers or wing-cases, because they

EMBRYO.

[ 280 ]

EMBRYO.

cover and protect the subjacent pair of
membranous wings of these insects when
not in use.

The elytra may be regarded as consisting
of an elongated, depressed fold of the inte-
gument, comparable to the web between the
fingers, or that of the bat's wing. Four
structures are distinguishable in them : —
1, an outer, firmly adherent, epidermic layer,
composed of minute cells, frequently un-
distinguishable, or at least only to be de-
tected in parts ; this layer is continued
around the margins of the elytra, so as to
cover their inferior surface also, forming, 2,
the inner epidermic layer, in which the cells
are stated to be less distinct, more rounded,
and more closely placed than those in the
upper layer, hence presenting a more di-
stinctly angular form ; this layer is easily
detached from the elytra, ana its surface
next the body of the insect is frequently
furnished with a number of very minute
hairs, or spiniform papillae directed back-
wards (PI. 34. fig. 2). Beneath the outer
epidermic layer is 3, a layer of dark resinous
pigment ; whether contained in cells or not
has not been determined. 4, an intermediate
portion, composing the principal thickness
of the elytrum, representing the two fused
strata of the cutis, and consisting of a number
of fibres, running in different directions,
variously interlacing, anastomosing, and
crossing, so as to form numerous plates or
secondary layers, many of which present a
fenestrated appearance ; as many as sixteen
of these plates have been separated.

The veins or nerves of the elytra either
traverse the intermediate thick layer of the
elytra, or run between its under surface and
the inner epidermic layer, to which they
sometimes remain adherent. See INSECTS.

The structure of the elytra can only be
made out by macerating them for a long
time in solution of caustic potash, or water.

BIBL. Schmidt, Taylor's Sc. Memoirs,
v. 16; Meyer, Midler's Archiv, 1842, 12;
Nicolet, Ann. Sc. Nat. 3 s6r. vii. ; and the
BIBL. OF INSECTS.

EMBRYO, OP PLANTS.— This is the
name applied to the rudimentary plant con-
tained in all true seeds. Seeds containing
embryos are borne exclusively by Flowering
Plants ; and while the external conditions
under which the seeds are produced afford
the character for the first subdivision of this
province of the Vegetable Kingdom (Ax-
GIOSPERMS and GYMNO SPERMS), the struc-
ture of the embryo is taken as the most

striking character in further subdividing the
Angiospermous Flowering Plants into their
two great natural groups, viz. Monocotyle-
dons and Dicotyledons, in which, respect-
ively, the embryo bears one or two cotyle-
dons or seed-leaves. Cases occur both
among the Dicotyledons and the Monocoty-
ledons where the typical structure is de-
parted from. Thus in Orobanchaceaa (Dico-
tyledons) the embryo is a mere globular
mass of cellular tissue, the result of an arrest
of development, the cotyledons and radicle
never becoming distinct; the same is the
case in the Orchidacege among the Monoco-
tyledons, the embryo not advancing beyond
the state of a globular mass of parenchyma.
The relation of such embryos to the perfect
forms is well illustrated by comparing the
stages of growth of embryos which acquire
fully-developed cotyledons and radicle (fig.
192). In Cusciita, a leafless plant, the

Fig. 192.

A young Dicotyledonous embryo in successive stages
of development. All exhibit the suspensor ; and 4 has
the cotyledons appearing, separated by a notch. Mag-
nified 50 diameters.

embryo has no distinct cotyledons. Other
anomalies of another kind also occur. Some
Monocotyledons, such as those of Grasses,
have the rudiment of a second cotyledon ;
but this is above and not opposite the other
larger one. In Dicotyledons the cotyledons
are not unfrequently unequal, and some-
times soldered together. In the Coniferse
the embryos appear to have four, eight, or
more cotyledons in different cases ; but it is
stated that there exist only two, divided or
compound, cotyledons (see SEEDS).

Occasionally more than one embryo occurs
in a seed (see POLYEMBRYONY) ; and in the
Coniferse a number of embryos are at first
produced, of which one only becomes per-
fectly developed (see GYMNOSPERMIA).

The embryo sometimes constitutes the
whole mass of the seed, merely enclosed in
the coats ; in other cases it is embedded in
a mass of albumem. In the former case the
tissue of the cotyledons often assumes cha-
racters similar to those of the ALBUMEN,
serving as a receptacle for stored nutriment
for the germinating plant, in the form of

EMBRYO-SAC.

[ 281 ]

ENCALYPTA.

fleshy secondary deposits, starch, oil, &c.
The position of the embryo in the albumen,
or the modes in which the embryo is folded
up within the seed-coats, are of great im-
portance in systematic botany, for the charac-
terization of families. Particulars regarding
these points, and the manner of examining
them, are given under the head of SEED.
The development of embryos is described
under OVULE. See also ORCHIDACE^:,
OROBANCHACE^E, CUSCUTA.

BIBL. Henfrey - Masters, Sot. 634;
Brongniart, Ann. Sc. Nat. xii. 14, &c. ;
Jussieu, ibid. 2 se"r. xi. 341 ; St.-Hilaire,
Ann. Sc. Nat. 2 ser. v. 193; Duchartre,
Ann. Sc. Nat. 3 ser. x. 207 ; Hofmeister,
Abh. sacks. Ges. Wiss. vi. & vii. ; Sachs,
Sot. 553; and the BIBL. of the articles
OVULE, SEED, &c., above referred to.

EMBRYO-SAC, OF PLANTS.— A cell
which becomes enlarged into a sac in the
substance of the upper part of the nucleus
of the ovule or rudiment of the seed. In
the cavity of this are developed the germinal
vesicles (PI. 47. figs. 3, 4, 5), one of which
(occasionally more), after fertilization, gives
origin to the EMBRYO. The most common
condition of the embryo-sac is that of a large
ca,vity excavated in the nucleus, bounded by
its own cell-membrane, and containing abun-
dant protoplasm, and subsequently germinal
vesicles and endosperm-cells (see OVULE).
Not unfrequently, however, it becomes de-
veloped into diverse saccate processes, either
pushing their way through the substance of
the nucleus in variable directions (Scrophu-
lariacece &c.), or emerging from the micro-
pyle, coming to meet the pollen-tube ( Vis-
cwm), or even so much developed externally
that the embryo is formed and perfected
altogether outside the nucleus (Santaluni).
These and other conditions are further de-
scribed under OVULE. When the germinal
vesicle is fertilized, and is undergoing deve-
lopment to produce the embryo, the embryo-
sac often becomes completely filled with
endosperm-cells, at first free, but afterwards
adhering together through their crowded
condition. These may persist and form an
endosperm to the seed, as in Nuphar, where
there is an additional episperm formed out-
side the embryo-sac from the substance of the
nucleus. Albuminous seeds generally have
either an episperm or an endosperm alone.
In exalbuminous seeds the endosperm ori-
ginally existing inside the embryo-sac be-
comes absorbed through the pressure of the
growing embryo, the embryo gradually filling

up the cavity, and by further expansion ob-
literating the embryo-sac and nucleus. See
ALBUMEN, of Seeds.

In the Coniferse the embryo-sac, origi-
nally formed by the excessive expansion of
one of the cells near the apex of the nucleus,
becomes subsequently filled up by cellular
tissue, in the upper part of which become
developed the bodies called corpuscula, each
of which possesses a kind of secondary
embryo -sac of its own, in which the ger-
minal vesicles are developed (see GYMNO-
SPERMIA).

The term embryo-sac might also be ap-
plied to the large cell at the base of the
archegonia of the FERNS, LYCOPODIACE^,
MOSSES.

BIBL. See OVULE and GYMNOSPERMIA.

EMPUSI'NA, Cohn. See SPORENDO-

NEMA.

EMYD'IUM, Doyere (Echiniscus,
Schultze). — A genus of Arachnida, order
Colopoda, family Tardigrada.

Char. Head furnished with appendages j
mouth conical, without appendages or ter-
minal sucker ; epidermis semisolid, present-
ing, especially on the upper surface of the
body, an evident annular division.

E. testudo (PL 50. fig. 7). Reddish-
brown ; body ovoid, opaque ; snout conical,
presenting traces of division into three
rings ; head indistinctly divided into three
segments, the first and third presenting short
setiform filaments supported upon very short
tubercles, the second with a palpiform, blunt
and flattened appendage ; pharyngeal tube
very slender; styles straight ; bulb without
an internal jointed framework; eye-spots
small, oval, simple, most visible at the
under aspect of the body; trunk divided
into four simple rings, with spines and long
filaments; legs three-jointed, each with
large and strong claws, the posterior pair
with a kind of spur also at the back part of
the lower margin of the second joint; move-
ment excessively slow ; length, from the
end of the extended snout to the posterior
border of the fourth ring, 1-80". Found on
the moss covering tiled roofs ; common.

E. spinulosum I

E. granulatum \

BIBL. Doyere, Ann. Sc. Nat. xiv. p 279

ENALLOSTE'GIA. — One of D'Or-
bigny's orders of Foraminifera, having the
chambers alternate in two or three rows,
not spiral ; such as Polymorphina and Tex-
tularia.

ENCALYP'TA, Schreb.— Agenusof Ca-

ENCALYPTA.

[ 282 ]

ENCIIELYS.

lymperaceae (Pottioid Mosses), containing
several British species.

BIBL. Wilson, Eryol Br. 140; Berk.
Handb. 246.

Fig. 193.

Fig. 194.

Encalypta commutata.

Pig. 193. A single plant. Magnified 5 diameters.
Fig. 194. The mouth of the capsule, showing the
rudimentary peristome. Magnified 50 diameters.

Fig. 195.

Fig. 196.

Encalypta commutata.

Fig. 195. Capsule on stalk, with vaginule at base,
and calyptra above. 10 diameters.

Fig. 196. Capsule enclosed in its calyptra. 20 di-
ameters.

ENCEPH'ALOID, or ENCEPHALOID
CANCER. — That form of cancer in which
the morbid substance has the appearance
and consistence of the medullary part of the
brain; hence sometimes called medullary
cancer.

See TUMOURS, CANCEROUS.

ENCHE'LIA, Ehr.— A family of Infu-
soria.

Char. No carapace, ciliated, oral and
anal orifices at opposite ends of the body.

Ehrenberg distinguishes the genera thus :

Mouth
tooth- H
less.

Sur-
face
with
very
fine
cilia

Sur-
face
with
evi-
dent
cilia

„ , .

double . . .Dlsoma.

Mouth directly trun-
cate, without a lip ...

Mouth with te eth .............................. Prorodon.

Dujardin's family Enchelia bears no re-
lation to that of Ehrenberg. He defines it
as consisting of animals partly or entirely
covered with diffused cilia, no mouth ; and
subdivides it thus : —

Cilia at one end ..................... Acomia,

Ciliain a longitudinal furrow Gastrochceta.

all over

{Cilia all alike ........................ EncheJys.
Both cilia and trailing ) . ,

retractile filaments } ...... Alyscum.
One long straight )
cilium posteriorly f ............... Uronema.

Kent includes in the family : Enckelys,
Metacystis, Perispircij Anophrys, Colpoda,
and Tillina.

ENCHEL' YODON,Cl.&Lach.— A genus
of Holotrichous Infusoria.

Char. Free, ovate, narrowed in front;
mouth terminal, with a longitudinally pli-
cate oesophagus.

Two species ; freshwater and marine. (01.
& Lachm. Inf. 316; Kent, Inf. 503.)

EN'CHELYS, Hill.— A genus of Infu-
soria, family Enchelia, Ehr. (TRACHELINA.
01. & Lach.).

Char. Body single, ovate, free, very finely
ciliated on the surface; mouth without
teeth, ciliated, directly truncated. Bog-
water and infusions.

E.pupa, E. (PI. 30. fig. 48). Body ovate,
turgid, attenuated in front, containing yel-
lowish-green granules; length 1-144". "

ENCHONDROMA.

[ 283 ]

ENDOSMOSE.

E. farcimen. Smaller than the last,
1-143*2"; internally whitish.

E. arcuata, 01.

Two other species.

Dujardin's genus Enchelys belongs to Cy-
clidium.

BIBL. Ehrenb. Inf. 298; Dujardin, Inf.
385; Stein, Inf. 137; Clap. & Lashm,/™/.
309 ; Kent, Inf. 509.

ENOHONDRO'MA. See TUMOURS.

ENC YONE'MA, Kiitz.— A genus of Dia-
tomaceae.

Char. Frustules resembling those of Cym-
bella, arranged mostly in longitudinal series,
in gelatinous tubes; freshwater.

Valves very variable in form, even in the
same tube, showing how little dependence
is to be placed upon this feature as a cha-
racter.

E. prostratum (PI. 19. fig. 10). Fila-
ments nearly simple; length of frustules
1-1560 to 1-600".

E. cwspitosum. Filaments divided at the
ends, tufted.

2 other European species, and 2 foreign.

BIBL. Kiitzing, Bacitt. 82, and Sp. Alg.
61; Rails, Ann. N. H. 1845, xvi. Ill;
Berkeley, ib. 1841, vii. 449 ; Smith, Brit.
Diat. ii. 68 ; Rabenhorst, Fl. Alg. i. 85.

ENDIC'TYA, Ehr.=CosciNODiscus in
part. E. oceanica—C. oc. K.

ENDOCAR'PON, Hedw.— A genus of
Lichens, tribe Pyrenocarpei, with pale peri-
thecia immersed in a peltate or squamiiorm
coriaceous thallus ; growing on rocks, in
streams, and on the ground.

4 British species : E. miniatum,Jluviatile,
rufescens, and hepaticum.

BIBL. Leighton, Angioc. Lich., Ray Soc.
1851, 10, pi. 1, and Lich. Fl. 441 ; Tulasne,
Ann. So. Nat. 3 ser. xvii. 90, 213, pis. 10 &
12; Hook. Br. FL ii. pt. 1. 159; Schserer,
Enum. 230, pi. 9. fig. 2.

EN'DOCHROME.— This term is applied
to the cell- contents, or the miscellaneous
collection of substances and structures en-
closed in the cavity of a cell. In an Alga,
therefore, like Zygnema, it comprehends
the primordial utricle or layer of protoplasm
lining the cell-wall, together with the
chlorophyll-globules or vesicles, starch-
granules, nucleus, and liquid and granular
protoplasm contained in the cavity of the
cell. It is perhaps a useful word in roughly
describing a species, but it is too indefinite
to be admissible in any accurate description
of cellular structures; moreover, as it is
not a definite collection of substances, nor

always coloured, the use of the term cell-
contents is to be preferred in all cases, as
not indicating any positive characters.

ENDOCOCCUS, Nyl.— A genus of Li-
chens containing the parasitic species of
VERRUCARIA.

BIBL. Leighton, Lich. Fl. 492.

ENDODRO'MIA, Berk. A curious ge-
nus of Mucorini (Phycomycetous Fungi),
distinguished by a very delicate vesicle per-
forated by the stem, filled with delicate
branched radiating threads and globose
spores, each of which has a nucleus en-
dowed with active motion. E. vitrea, the
only species, is found on sticks in damp
woods.

BIBL. Hook. Jn. iii. 79 ; Berk. Outl. 408.

EN'DOGEN. See MONOCOTYLEDONS.

ENDO'GONE, Lk.— A genus of Muco-
rini (Phycomycetous Fungi), consisting of
one or two Hypogaeous species, the flocci
being collected into a globose spongy mass,
and terminated by globose vesicles, solitary
or in fascicles. Two species, E. pisif omits,
Lk., and E. lactiflua, B. & Br., have been
found in this country.

BIBL. Ann. N. H. 1846, xviii. 81 ; Berk.
Outl. 409.

ENDOS'MOSE, Osmosis or Dialysis.—
This name is applied to a phenomenon
which takes place when two different li-
quids, having an attraction for each other,
are separated merely by a porous diaphragm
or an organic membrane. A diffusion takes
place, by which the liquids become mixed,
but one of them flows more rapidly into
the other. Thus when alcohol and water
are so placed, the water flows into the
alcohol (endosmose) much more strongly
than the alcohol into the water (exosmose).
The same attraction occurs when syrup or
a solution of gum is substituted for the
spirit, and also alkaline salts. When acids
or acid salts are placed in the same relation
to water, the current is strongest towards
the water. Acids and alkaline solutions
exert the strongest action, neutral sub-
stances the weakest. Dilute solutions act
more efficiently (proportionally) than strong
ones. The importance of the effects of
endosmose on microscopic objects viewed in
liquids, has been mentioned in the INTROD.
(p. xli). Delicate structures are often ad-
vantageously wetted with dilute solution
of sugar, common salt, or glycerine, to
prevent the changes from endosmosis which
result from the use of pure water.

Graham divided organic matters into two

ENDOSPERM.

[ 284 ]

ENOPLID^E.

classes : the crystalloid, or those which will
pass through a porous membrane, as soluble
salts ; the colloid, or those which will not,
as albuminous matters. This subject is of
special interest in regard to the nutrition
of animal and vegetable cells. For if their
walls are impervious to the so-called colloid
substances, a cell may be bathed with them,
and yet have to produce its own sarcodic
matter or protoplasm.

BIBL. Fischer, Pogg. Ann. xi. 126 j Du-
trochet, Cycl. Anat. and Phys. ii. 98 ;
Works on Physics, as Butf^ Experim.-Physik ;
Pouillet, EUm. d. Physique ; Peschel, Phy-
sirs, &c. ; Graham, Proc. Roy. Soc. vii. 83 ;
Watts, Diet. (Dialysis) ; L'Hermite, Ann.
Sc. Nat. 4 se"r. ii. 73 ; Nageli, Phys. Vnters. ;
Hoppe-Seyler, Chim. Phys. 11 j Rod well,
Diet. Sc. 162.

EN'DOSPERM. See ALBUMEX, of
Plants.

EN'DOSPORE.— The name applied by
some authors to the inner coat of spores.
See SPORE.

ENERTHENETMA, Bowm.— A genus
of Myxomycetes interesting from the fact
that the spores have been observed in situ ;
they are produced, five or six together, in
globular sacs (asci) attached to the free
apices of the filaments of the capillitium,
which arise from a disk at the top of the
percurrent stem (PI. 27. fig. 9). E. ekgans
was found by Bowman near Wrexham;
and it has since been found in South Caro-
lina,, and in Scotland.

In the clustered spores it resembles
Badhamia and some species of Reticularia
figured by Corda.

BIBL. Bowman, Linn. Tr. xvi. 151, pi.
16 ; Berk, and Broome, Ann. N. H. 1850.
v. 366, pi. 11. fig. 7.

ENHYDROSO'MA, Boeck.— A genus
of Copepodous Entomostraca.

E. curvatum, in dredgings. (Brady, Cope-
pocla, Ray Soc. ii. 97.)

ENOP'LID^E, Duj.— A tribe of Nema-
toid Entozoa, distinguished by an oral or
pharyngeal armature, consisting either of
styles, hooks, or rods (bacilli). The mem-
bers are microscopic, and live in fresh or
sea- water, whence they sometimes find their
way into the alimentary canal of higher
animals. Genera :

Dorylatmus. Filiform, narrowed at the
ends ; mouth tubular, retractile, armed with
a single very long horny style ; male with
two equal, short, falciform spicules ; fe-
male with the vulva in the middle of the

body, the uterus divided into two opposite
branches ; ova large, oblong.

D. stagnalis. In the intestines of the
carp and Gasterosteus. D. marinus ; marine.

Passalu'rus. Fusiform, elongate, nar-
rowed behind, with a subulate tail, or sud-
denly narrowed ; head obtuse j mouth with
three oblong pieces (jaws), united by a re-
sisting folded membrane ; oesophagus cla-
vate, succeeded by a broader stomach ; skin
transversely striate ; male with a single
spicule ; female with the vulva near the
stomach ; uterus and ovaries simple ; egga
large, oblong.

P. ambiguiis. Large intestine of the
rabbit and hare.

Enop'lm. Filiform, narrowed at the
ends, most behind ; head angular or trun-
cate, with a few opposite setaB ; mouth with
three uncinate jaws ; oesophagus almost
cylindrical, cavity triquetrous ; tail ending
in a kind of sucker ; one or more red eye-
like spots on the oesophagus ; skin smooth j
male with a supplementary orifice (anus or
sucker) in front of the genital orifice, and
with two equal curved spicules ; vulva near
the middle of the body ; uterus divided into
two opposite branches j eggs elliptical.
Marine and freshwater.

Oncholai'mus. Filiform, more or less
narrowed at the ends; head obtuse; buccal
cavity large, with two or three curved or
hooked jaws, placed lengthwise, at least one
with a prominent tooth j oesophagus elon-
gate, nearly cylindrical ; no stomach ; tail
apparently terminated by a sucker; skin
smooth. Male — tail suddenly narrowed,
short ; spicules two, equal. Female — vulva
near, or slightly behind the middle; uterus
two-branched ; eggs elliptic, large. Marine
and freshwater ; length 1-10".

Anguil'Ma (RJiabditis). Pharynx with
two or three longitudinal bacilli.

Atrac'tis. Mouth with two or three
jaws ; spicula two, unequal.

Doubtful genera :

Amblyu'ra, Ehr. Filiform, mouth trun-
cate, with cirrhi ; tail subulate, slightly ex-
panded at the end, where there is a sucto-
rial papilla ; spicule single, retractile, with-
out a sheath. Probably species of Oncho*
laimus or Enoplus.

A. serpenttilus= Vibrio s., Miiller. Found
in an old vegetable infusion.

A. gordius= Vibrio g.} Miill. In marine
infusions.

Phanogk'ne. Filiform, pointed behind ;
mouth truncate, bilobed, with cirrhi, and

ENTEROBRYUS.

[ 285 ]

ENTOMOSTRACA.

with red eye-spots behind the head; spicule
single.

P. micans. Eye-spots contiguous; cirrhi
two. In the intestine of the larva of a
neuropterous insect.

P. barbiger. Cirrhi four ; red spots se-
parate. In stagnant water.

Enchilid'ium. Filiform, a single red eye-
spot, as broad as the body, situate at some
distance from the head. Marine.

See ANGUILLTILLDJE.

BIBL. Dujardin, Helminth. 236; Nord-
mann, Lamarck's Anim. sans Vert. iii. 564 ;
Bastian, Linn. Tr. xxv. 73.

ENTEROBRY'US, Leidy.— A supposed
genus of Kiitzing's Leptomitese, probably
the mycelium of some fungus, found in the
intestines of insects.

ECCRI'XA, Leidy, is another of these
forms.

BIBL. Leidy, Proc. N. H. Soc. Philadel
1849, 225, Ann. N. H. 1850, v. 72 ; Robin,
Veget. Paras. 1853, 395, pi. 4. figs. 5, 6.

ENTERO'COLA, Van Ben. — A genus
of Copepodous Entomostraca.

E. ei-uca, is found adhering to the intes-
tine of Ascidia intestinalis. (Brady, Cope-
poda, Ray Soc. i. 147.)

ENTE'ROMORTHA, Link.— A genus of

Ulvacese (Confervoid Algae), consisting of
freshwater and marine plants, with branch-
ed, tubular, green fronds, the walls of the
tubes being composed of a single flat layer
of polygonal cells. Reproduction by ciliated
zoospores, formed in considerable numbers
from the transformed contents of the cells
(PI. 9. fig. 4). In this genus, Thuret states
that two forms of zoospores occur, — one
large and four-ciliated ; the other, in fronds
with a yellower tint, smaller and with two
cilia; both kinds germinate. The zoospores
escape from the cells by a pore on the outer
surface (PI. 9. fig. 4 a) near the centre of
the cells ; and the latter persist for some
time in an empty condition. The marine
forms, of which nine species are described
by Harvey, are mostly from 1-2" 'to several
lines in diameter, but many inches long.
E. Grevtilei, Thuret (Ulva Lactuca, Grev.,
Harv.), however, is thicker and saccate,
finally bursting. E. intestinalis, which
grows both in the sea and in brackish- and
freshwater ditches, often attains a length of
2 feet and more, and varies in thickness
from 1'" to 2-3".

BIBL. Harvey, Mar. Alg. 213, pi. 25 D,
Phyc. Brit. pis. 63, 262, 282 ; Greville, Alg.
Brit. 179, Sc. Crypt. Fl. t. 313, Eng. Sot.

2137 & 2328 ; Thuret, Ann. Sc. Nat. 3 se*r.
xiv. 224, pi. 20. figs. 8-12 ; Mem. de Cher-
bourg, ii. ; Rabenhorst, Fl. Alg. iii. 312.

ENTERO'PLEA, Ehr.— A genus of Ro-
tatoria, of the family Hydatingea.

Char. Eye-spots none; teeth absent; foot
forked.

E. hydatina (PL 43. fig. 27). Body co-
nical, hyaline ; foot small; aquatic; length

1-120":

Probably the male of Hydatina.

BIBL. Ehrenb. In/us, p. 411.

ENTODIN'IUM, Stein.— A genus of Pe-
ritrichous Infusoria.

Char. Free, ovate, flattened; surface
smooth, indurated ; often with one or more
terminal spines. Three species ; in the ru-
men and reticulum of Ruminants.

BIBL. Stein, Inf. ii. 168; Kent, Inf.
653.

ENTOGO'NIA, Grev.— A genus of fossil
Diatomaceae.

Char. Frustules in side view triangular,
containing a central triangular figure, having
a broad border divided by transverse costae
into punctate or cellulate compartments :
= species of Triceratium.

11 species. Barbadoes.

BIBL. Greville, Qu. Mic. Jn. 1863, 235
(figs.).

EN'TOMIS, Jones.— An extinct bivalved
Entomostracan, known by its oval, trans-
versely sulcate, and sometimes concentri-
cally wrinkled valves. The sulcus is nuchal
and much stronger than in some of the Cy-
pridiniform allies marked with this feature.
Silurian, Devonian, and Carboniferous.

BIBL. Jones, Mem. Geol. Surv. Edinb.
1861, 137 ; Ann. N. H. 1879, iv. 183.

ENTOMONE'IS, Ehr.=Amphiprora, pt

ENTOMOSTE'GIA. — One of D'Or-
bigny's orders of Foraminifera, having the
chambers in two rows, alternate, coiled
into a spiral. This alternation of chambers,
however, in the coiled Foraminifera arises
from very different modes of growth, and
is not a group-character. It is due : — 1 to
bilateral asymmetry (Cassidulina'} ; 2, to
lateral elongation and intercalation of the
chambers in Robertina (Bulimind) • 3, to
extreme alar division with interdigitation
of the chambers on one face (Amphistegina) j
4, to irregular growth of semi-annular
chambers (Heterostegina) ; and 5, to tent-
like cavities under umbilical flaps (Asterige-
rind).

ENTOMOSTRACA.— A division of the
class Crustacea.

ENTOMOSTRACA.

[ 286 ]

ENTOMOSTRACA

Char. Free ; freshwater or marine ; body
more or less distinctly jointed, mostly con-
tained in a horny, leathery, or brittle shell
or carapace, formed of one or more pieces,
often bivalve ; branchiae attached eitner to
the jaws or legs ; legs jointed, and more or
less ciliated ; development accompanied by
a regular moulting or change of shell, some-
times amounting to metamorphosis.

Many of the Entomostraca are very com-
mon in ponds, pools, and other collections
of water. When examined with the naked
eye, in a bottle or glass containing the water,
they appear as minute specks, generally in
active and often in jerking motion.

The shell is often beautifully transparent,
sometimes spotted with pigment, variously
striated, reticular, or notched, sometimes
spinous or tuberculated. It consists of chi-
tine impregnated with a variable amount
of carbonate of lime, which is sometimes so
great as to render it brittle, and to cause
copious effervescence on the addition of a
dilute acid ; and when boiled it turns red,
like the shell of a lobster. It varies in
structure, sometimes consisting of two
valves, united at the back, resembling the
bivalve shell of a mussel ; at others it is
simply folded at the back so as to appear
bivalve, without really being so ; or it con-
sists of a number of rings or segments. It
often presents a reticular appearance re-
sembling that of a cell-structure.

The body itself, which is more or less in-
timately connected with the shell, is mostly
divided into numerous segments. The head
is furnished with one or two pairs of an-
tennae ; the superior or anterior are usuaDy
smallest, and in some genera easily over-
looked (PI. 20. fig. 28 a) ; sometimes one or
both of them are furnished in the male
with a hinge-joint, allowing considerable
flexure, so as to permit of its grasping the
female (PI. 20. fig. 8 «, of male; 9 a of fe-
nale) ; sometimes they are long, and pro-
vided with a tuft of filaments (PI. 20. figs.
17,18); at others they are simply long, and
filiform or setaceous (fig. 38). In some
Cypridinidae and Concnceciidae, the upper
antennae become organs of special sense
(smell or hearing), being clothed with
toothed club-shaped appendages, which
arise directly from the antennae (Conchcecid),
or from its "bristle-shaped appendages (Cy-
pridina). The inferior pair or posterior
antennae vary in size and structure like the
former, being sometimes large and branched
(fig. 28 6), and serving to row the animals

through the water, at others resembling
legs (tigs. 5, 17, &c.). In some genera they
are furnished with curious appendages,
effecting the purpose of the hinge-jointed
superior antennae. In some, again (Cythe-
ridae), the lower antennas (PI. 19. fig. 37)
are armed with alougcurved2- or3-jointed
urticating seta (6), connected at its base
by a duct with a vesicular gland situated
in the anterior part of the body (a). An
external stalked vesicle is also sometimes
found attached to this antenna.

The eyes are usually large, the pigment
black or red, and the muscles and the ner-
vous branches distributed to them from the
cephalic ganglion very distinct.

A labrum or upper lip is often present,
compressed and terminated by a hairy lobe
(PI. 20. fig. 35) ; sometimes also a labium.
Behind these are situated two mandibles,
furnished with either blunt or pointed teeth,
often having a palpus or palp-like organ
(fips. 11, 20, 34). Next to these, comes a
pair of maxillae, jaws or foot-jaws (figs 12,
36), furnished with spines, hooks, or claws,
and sometimes branchiae (fig. 21). Behind
these is a second pair of foot-jaws (figs. 13,
22). The legs are variable in number and
structure; they are often furnished with
flattened processes, fringed with beautifully
ciliated or plumose filaments (figs. 30, 31,
32), thus exposing a large extent of surface
to the water, by which respiration is effec-
ted; hence they represent gills, and are
called branchiae or branchial legs or feet ;
similar branchiae are often appended to the
foot-jaws ; and they are in constant motion,
even when the animal is at rest.

In some genera, as Canthocamptus, Cy-
clops, and DiaptomuSy the respiration is ex-
clusively anal ; the water being drawn into
and expelled from the rectum at intervals,
as in many aquatic larvae of insects.

As the structure and arrangement of these
parts afford characters for distinguishing
the genera &c., the details are given under
their respective names.

The abdomen is of variable length, join-
ted with a variously lobed post-abdomen,
often resembling a tail in appearance (figs.
3, 8) ; sometimes it is bilobed ; sometimes
Burnished with a kind of spur near the end,
:or supporting the ova within the shell,
tn some genera the external ovaries or ovi-
sacs containing the ova pass out between
two of the abdominal joints, yet remaining
attached, and giving a remarkable appear-
ance to the animals (figs. 9, 38). The in-

ENTOMOSTRACA.

[ 287 ]

ENTOMOSTRACA,

testinal canal is usually straight or but
slightly curved ; sometimes, however, it is
coiled (fig. 7). The Entomostraca are
mostly herbivorous, although some are car-
nivorous. The sexes have not been distin-
guished in all the Eutomostraca, although in
some they are perfectly distinct. It appears
also that in certain of them, reproduction
takes place according to the law of alterna-
tion of generations — females only being
produced through several generations, and
the males appearing only at certain seasons.

The spermatozoa are often of most re-
markable structure (see SPERMATOZOA).
The ova are mostly rounded; sometimes
they are covered with spines, and often
brilliantly coloured. They are either
hatched in the external ovaries mentioned
above, or in a space between the body of
the parent and the posterior part of the
shell ; or they are deposited in masses upon
and glued to water-plants, and hatched in-
dependently of the parents.

At particular seasons of the year, the ova
in certain species are furnished with thick
capsules, and imbedded in a dark opaque
substance presenting a minutely cellular
appearance, and occupying the above-men-
tioned interspace between the body of the
animal and the back of the shell (fig. 37 «).
This is called the ephippium, and the ova
ephippial or winter ova (EGGs).

When first hatched, the young (fig. 16)
differ very strikingly in form and structure
from the adults (figs. 8, 9).

The larval forms of the higher Crustacea
often bear considerable resemblance to the
perfect Entomostraca.

The minute structure of the Entomostraca
is difficult to determine ; for although the
body and shell are frequently comparatively
transparent, the parts are exceedingly deli-
cate and soft, so that they are easily crushed
and mutilated,and their appearance distorted.

The Entomostraca are best preserved in
solution of chloride of calcium or glycerine
(see PRESERVATION). Some use glycerine-
jelly.

A large number of Entomostraca are
found fossil ; among which must be specially
mentioned the Trilobites, of which 1600
species are described.

The following systematic arrangement
comprises the most common genera and
species. Numerous others are described,
Brady enumerating 67 genera of the Cope-
poda only ; these are briefly mentioned un-
der the individual heads.

Legion 1. Lophyropoda. Branchiae at-
tached to the organs of the mouth ; legs
few, not exceeding five pairs, serving for
locomotion, articulation mostly more or
less cylindrical ; antennae two pairs, one
pair used as organs of motion.

Order 1. Ostracoda. Shell consisting of
2 valves, entirely enclosing the body ;
feet 1-3 pairs, adapted for progression ;
no external ovary.

Sect. 1. PODOCOPA. Inferior antennae sim-
ple, subpediform, geniculate, clawed
at the end. (Includes all the fresh-
water and most of the marine Ostra-
coda.)

Fam. 1. CYPRID^!. Superior antennas
mostly 7 -jointed, with a dense brush
of long setae ; eye usually single ; feet
2 pairs, the last bent up between the
valves ; abdominal rami 2, elongate,
clawed at end.

Gen. : Cypris (PI. 20. figs. 5 & 19), Can-
dona, Cypridopsis, Paracypris, Aglaia,
Notodromas, Pontocypris, Argillcecia,
Bairdia, Macrocypris, and Chlamydo-
theca.

Fam. 2. CYTHERID^:. Superior antennas
6-7 -jointed, setigerous or spinous ; in-
ferior 4-5-jointed, without a brush;
feet 3 pairs, ambulatory ; post-abdo-
men rudimentary, consisting of 2 very
small lobes. (Comprises most of the
marine species, and almost all the nu-
merous fossil species.)
Gen. : Cythere (PI. 20. fig. 26), Limnocy-
there, Cytheridea, Eucy there, Ily abates,
Loxoc&ncha, Xestolebei'is, Cytherura,
Cytheropteron, Bythocythere, Cythe-
rideis, Sclerochilus, and Parado.ro-
stoma.

Sect. 2. MYODOCOPA. Inferior antennas
2-branched : one branch rudimentary,
the other powerful, many-jointed, with
long natatory setas ; mandibular palp
very large, subpediform, geniculate, not
branchial. Post-abdomen with 2 broad
plates, clawed.

Fam. 3. CYPRIDINID^E. Feet 1 pair; ver-
miform, annulated, long; mandibles
obsolete ; second pair of jaws with a
large branchial plate ; eyes, 2 com-
pound, 1 simple.

Gen. : Cypridina, Asterope, Bradyciiietus
(Eurypylus), Philomedes, Cylindrole-

ENTOMOSTRACA.

[ 288 ]

EXTOMOSTRACA.

beris (CyprideUa, Cyprella, Entomis ?,
fossil).

Fam. 4. ENTOMOCONCHIB^E.

Gen. : Heterodesmus, Entomoconchus.

Fam. 6. CONCHCECIID^. Feet 2 pairs,
posterior rudimentary; mandibles di-
stinct j eyes none.
Gen. : Conchcecia, Halocypris.

Sect. 3. CLADOCOPA. Inferior antennae
2-branched, both branches well deve-
loped, natatory ; upper antennae nata-
tory, not geniculate, with a lash of long
setae ; mandibles distinct, palp short ;
2 pairs of thoracic appendages — ante-
rior large, natatory, posterior membra-
naceous and branchial.

Fam. 6. POLYCOPIDJE. Char. Those of

the section.
Gen. : Poly cope.

Sect. 4. PLATYCOPA. Lower antennae 2-
branched, flattened ; branches few-
jointed, with numerous setae. Supe-
rior antennae strong, geniculate, shortly
spiniferous ; mandibles small, palp
large ; 3 pairs of thoracic append-
ages, all maxilliform ; first and second
pairs of jaws with a large branchial
plate.

Fam. 7. CYTHERELLIDJE.
Gen. Cytherella.

Order 2. Copepoda. Shell jointed, forming
a buckler, enclosing the head and thorax ;
legs five pairs, mostly adapted for swim-
ming ; ovary external.

Fam. 1. CYCLOPID^:. Head consolidated
with the thorax; foot-jaws two pairs,
generally small ; fifth pair of legs rudi-
mentary ; eye single ; both superior
(larger) antennae in the male furnished
with a swollen hinge joint.

Cyclops. Foot-jaws large and strong,
branched ; ovaries double (PI. 20. figs.
8,9).

Canthocamptus. Foot-jaws small, sim-
ple ; ovary single (PI. 20. fig. 6).

Arpacticus. Foot-jaws stout, terminated
by a claw ; ovary single.

Alteutha. Foot-jaws small, simple ; body
flat ; a strong falciform appendage to
the fifth segment of the body on each
side (PI. 19. fig. 3).

Tachidius, Dactylopus, Delavallia.

Fam 2. DIAPTOMID^. Head consolidated
with the first joint of thorax ; foot-jaws
three pairs, well developed ; last pair
of legs differing in structure from the
others, and differing from each other in
the two sexes ; eye single, sometimes
pedunculated in the male ; right an-
tenna only with the swollen hinge-
joint in the male.

Diaptomus. Cephalothorax and abdo-
men each of five segments fPl. 20.
fig. 38).

Temora. Cephalothorax of five, abdo-
men of three segments.

Anoinalocera. Cephalothorax of seven,
abdomen of four segments (PI. 19.
fig. 6).

Dl08.

Fam. 3. CETOCHILID^;. Head consolidated
with first joint of thorax; foot-jaws
three pairs, strongly developed ; eyes
two ; right antenna only with the
hinge-joint in the male.

Cetochilus (PL 19. fig. 21).

Notodelphys. Provisionally (PI. 19. fig.

Legion 2. Branchiopoda. Branchiae at-
tached to the legs ; legs from four to sixty
pairs.

Order 1. Phyllopoda. Legs from eleven to
sixty pairs in number, joints foliaceous
and branchiiform, chiefly adapted for re-
spiration and not motion ; eyes two or
three, sometimes pedunculated ; antennas
one or two pairs, neither adapted for
swimming.

Fam. 1. BRANCHIPODIDA. Body not en-
closed in a carapace or shell ; antennae
two pairs, the inferior horn-like, and
with prehensile appendages in the
male ; legs eleven pairs.

Artemia. Tail simply bilobed; no ap-
pendages at the base of the cephalic
horns.

Branchipits. Tail formed of two plates,
cephalic horns with fan-shaped appen-
dages at the base (PI. 20. fig. 3).

Fam. 2. ASPIDOPHORA. Body enclosed in
a shell; antennae one or two pairs;
legs more than eleven pairs.

Apus. Shell flat, buckler-like ; antennae
one pair, small ; eyes sessile.

Nebalia. Shell folded at the back ; an-

ENTOMOSTRACA. [ 289 ]

ENTOMOSTRACA.

tennse two pairs, large : eyes stalked
(PL 19. fig. 28).

Fam. 3. DITHYBIDA. Bivalve.
Limnadia, Estheria, Limnetis.

Order 2. Cladocera. Legs four to six pairs,
chiefly branchial; eye single, and very
large ; antennae two pairs, inferior large,
branched and adapted for swimming.

Fam. 1. DAPHNIAD^J. Superior antennae
small; inferior large, two-branched;
legs five or six pairs, all enclosed within
the carapace ; eye single, large.

* (Daphnina.) Legs five pairs ; inferior
antennae two-branched, one branch four-, the
other three-jointed.

Daphnia. Head produced below into
a beak ; superior antennae very small
(PL 20. fig. 28).

Moina. Head rounded and obtuse ; su-
perior antennas large (PL 19. fig. 26).

Macrothrix. Head beaked, beak di-
rected forwards ; superior antennae
one-jointed, hanging from the beak
(PL 19. fig. 25).

Bosmina. Head terminating in a sharp
direct beak ; superior antennae long,
many- jointed, projecting from end of
beak (PI. 20. fig. 2).

Drepanothrix, Lathonura, Acantholeberis,
Ilyocryptus.

** (Sidina.) Legs six pairs ; inferior an-
tennae two-branched ; a row of spines arising
from the edge of larger branch; superior
antennae of moderate size.

Sida. One branch of inferior antennae
three-, the other two-jointed (PL 19.
fig. 27).

Daphnella. Both branches two-jointed
(PL 20. fig. 27).

Fam. 2. POLYPHEMIDJE. Inferior antennae
two-branched, one branch four-, the
other three-jointed; lower part of shell
forming a large vacant space for con-
taming the ova and young; eye very
large; legs four pairs, not contained
within the shell.

Polyphemus. Tail-like abdomen project-
ing outside the shell : freshwater (PL
19: fig. 29).

Evadne. Abdomen scarcely projecting
from the shell ; marine (PL 19. fig. 30).

Fam. 3. LYNCEID^. Superior antennae
very short ; inferior of moderate size,
branched, each branch three-jointed;
legs five pairs ; eye single, with a black
spot in front ; intestine convoluted,
having one complete turn and a half.
Eurycercus. Shell subquadrangular, ab-
domen forming a flat, densely serrated
plate (PL 20. fig. 39).
Chydorus. Nearly spherical; beak very
long, sharp, and curved ; inferior an-
tennae very short (PL 20. fig. 7).
Camptocercus. Ovoid ; abdomen long,
slender, and very flexible, serrated (PL
20. fig. 4).

Acroperus. Somewhat harp-shaped, with
an anterior inferior obtuse angle ; infe-
rior antennae rather long (PL 19. figs*
1,2).

Alona. Quadrangular, striated or grooved
longitudinally; inferior antennae short
(PL 19. figs. 4, 5).

Pleuroxus. Gibbous above and anterior-
ly ; obliquely truncate below ; first pair
of legs very large (PL 19. fig. 32).
Peracantha. Oval, lower end with a
curved posterior point, fringed infe-
riorly and antero-superiorly with strong
hooked spines (PL 19. fig. 31).
Monospilus.

See CRUSTACEA and SIPHONOSTOMA.
BIBL. Baird, Br. Entom. ; M. -Edwards,
Crustac. iii. ; Straus, Mem. Mm. 1819, v.
380, and 1821, vii. 33; Koch, Deutschl.
Crustac. ; Desmarest, Crustac. ; Jones, En-
tom. Cretac. Form. (Palceont. Soc.); Entom.
Tert., and Foss. Esthetics ; Zencker, Mullens
Archw, 1851 (Micr. Tr. i. 273) ; Morris,
Brit. Foss. 98 ; Lubbock, Linn. Tr. xxiii.
176, and xxiv. 197 ; Dana, Classif. Crust.
1853, Report on Crust. U. S. Exped. 1855 ;
Baird, Ann. N. Hist. 1862, ix. 132, and*. 1;
Grube, Esth. u. Limnad., Archiv Nat. xxxi.
1865 ; Plateau, Ann. N. H. 1869, iii. 12 ;
Schoedler, Cladocera (3 pi.), 1863; Brady,
Ann. N. H. 1864, xiii. 59 (New Ostracoda) ;
1868, ii. (Ostr. from Scandinavian Seas,
Mauritius, #c.); 1869, iii. 45; id. Linn. Tr.
1868, xxvi. 353 (Monogr. Ostracoda) ; and
Copepoda (Ray Soc.) ; Norman and Brady,
Monogr. 1867; Sars, Oversigt af Norges
Mar. Ostrac. 1865 ; Lilljeborg, De Crusta-
ceis, 1853; Zencker, Mull. Arch. 1850 (Cty-
pris) ; ibid. 1851 ; id. Arch. Naturg. 1854 ;
Hartog, Jn. Mic. S. 1880, 243 ; Brady and
Robertson, Ann. N. H. 1872, ix. 48 ; & Tr.
Palaontog. Soc. xxviii. ; Glaus, Copepodat
1881 j and the BIBL. of the genera.

ENTOrilYSALIS.

[ 200 ]

KYFUZOA.

ENTOPHY'SALIS, Kutz.— A genus of
Palinellaceae (Confervoid Algse).

C/tar. Frond globose, cartilaginous, con-
taining numerous more or less confluent
families of minute oblong cells.

E. f/ranidosa. On marine rocks. Dalmatia.

BIBL. Kiitzing, Pkyc. Gen. 177, pi. 18;
Rabenhorst, Alg. iii. 43 (fig.).

EN'TOPHYTES.— A general term ap-
plied to parasitic plants (chiefly Fungi),
growing in the interior of animal or vege-
table structures. See PARASITES, VEGE-
TABLE.

ENTOP'YLA, Ehr.— A genus of Diato-
maceae.

Char. Frustules prismatic, compressed,
compound, arcuate ; the two end valves
transversely striated, not alike, one of
them being convex outwards, the other
concave, and with a large pore (?) at each end.

E. nmtralis. Valves linear, rounded at
each end, with more than forty transverse
costse, traversed bv a longitudinal il-xuous
line ; inner plates in the adult state sixteen,
in the voung state only three ; marine, and
found in guano ; length 1-240", in the young
state 1-720" and with only six costae be-
tween the pores.

BIBL. Ehr. Bcrl. Be)'. 1848, 6 j Ann. N.
Hist. 1848, i. 393.

ENTOSI'PHON, Stein, =AnisoHcma, Duj.,
pt.

ENTOSOLE'NIA, Ehrenb.— A Lagena
is said to be Entosolenian if it has its
neck, or stolon-tube, growing inwards (in-
troverted). This was once thought to be
a generic character ; but it occurs in Pohj-
morjthina, and is not even of specific value.

Entosolenia (Layena) ylobosa, PI. 23.
fig. 23, «, 6, is a very common form recent
and fossil.

BIBL. Carpenter, Introd. Foram. 157.

Fig. 197.

Entosthodon Templetoni.
Fragment of the peristome. Magnified 100 diameters.

ENTOSTHODON, Schwagr.— A genus
of Funariaceae (Acrocarpous Mosses), inclu-

ding some of the Gymnostoma and Weisstee
of authors.

BIBL. Wilson, Bryol. Brit. 272 ; Berke-
ley, Handb. 175.

'EN'TOTHRIX, Kutz.— A genus of Os-
cillatoriaceae (Confervoid Algfe).

Char. Frond tubular, composed of nu-
merous very slender filaments, dei
twisted into a cord, and enclosed in a la-
mellar sheath.

E. fnnicularis. Filaments continuous,
brownish, flexuous. In long-kepi v.

BIBL. Kiitzing, Phyc. Gen. 224, pi. 5.
fig. 8; Rabenhorst, Fl. Alg. ii. 100 (fi-.).

ENTOZO'A.— A class of Venues j con-
taining the intestinal worms, £c.

The Entozoa are animals mostly residing
parasiticallv, during either the whole or a
part of their lives, in the cavities or in tin-
substance of the organs of other animal^ ;
they are very generally met with through-
out the Animal Kingdom; and they derive
their nourishment from the liquids of those
animals of which they constitute the \ ,
sites. Their form is mostly elongate, and
the body more or less distinctly jointed.

The integument consists of a delicate ho-
mogeneous epidermis, often thrown into
transverse folds ; sometimes also into longi-
tudinal folds, giving the body a wi<
appearance. In some species it is furnished
with papillae, spines, or hornv reil
prickles, either scattered over tjjie greater
part of the surface or confined to the ante-
rior extremity of the body, in the latter
case serving as organs of adhesion. Beneath
the epidermis is the cutis, intimately fu^ed
with or almost entirely consisting of layers
of transverse, longitudinal, and oblique ilat-
tened fusiform muscular fibres, resembling
the organic or unstriped muscular fibres of
the Vertebrata.

Beneath or in the substance of the skin,
in the Cestoid Entozoa, are numerous mi-
nute oval or rounded bodies, containing
carbonate and phosphate of lime; these are
regarded as forming the rudiments of a
cutaneous skeleton, and they possess a con-
centric laminated structure.

The form and structure of the head and
its apppendages, in the shape of hooks, suck-
ers, &c., are described with the genera and
species, as their form and arrangement are
used as generic characters.

The nervous system of the Entozoa is not
well known. In the cystic or larval forms,
none has been detected. In the Cestoids
and Acanthocephala, it consists of a single

ENTOZOA.

[ 291 ]

ENTOZOA.

cephalic ganglion, sending off branches to
the proboscis. In the Trematoda, of two
cesophageal ganglia, connected by a trans-
verse cord, and sending off two lateral
branches, which traverse the body longitu-
dinally. In the N ematoidea, it is composed
of a single longitudinal cord, furnished at
its origin and termination with a ganglion.

Organs of special sense appear to be
absent in the Entozoa, excluding that of
touch, which resides in the various cephalic
appendages. In some, especially in the
ciliated embryonic form, there are red or
black cervical spots, which have been re-
garded as eyes ; but they do not appear to
contain any refracting body comparable to
a lens. Hehninthologists have differed as
to the presence of a digestive, circulating,
and water-vessel system in the Cestoidea
and Acanthocephala, certain tubes found in
them being regarded as belonging to each
of these systems by different "authors ; the
longitudinal vessel-like tubes with lateral
branches terminating in a caudal pore, are
however, now regarded as excretory organs.
In most of the remaining Entozoa, the
digestive apparatus is well developed, the
mouth distinct, the posterior portion of
the alimentary tube much ramified, and
terminating either in a csecal extremity
or in a distinct anus. Remarks upon
these systems will be found under the
genera.

Propagation. — The Entozoa are propa-
gated by spontaneons division, by gemma-
tion or the formation of gemnipe, and by
sexual organs ; and they illustrate the law
of alternation of generations.

The spontaneous division, which is al-
ways transverse, differs from that of the
Infusoria and Zoophytes, in the new indivi-
duals produced not being perfect — a certain
number of organs only being reproduced,
as in the joints (proglottides) of the body
of the Cestoidea.

The formation of gemmae occurs in the
larval or cystic forms of Tania — Ccenurus
and Echinococcus.

In those Entozoa which are propagated
by sexes, the individuals are either herma-
phrodite or unisexual. In the Cestoidea the
sexual organs are usually repeated in each
joint, except those near the head. And it
appears that there are two kinds of ovaries
— one for the production of the germ (the
germinal vesicle and spot), and the other
for the yolk. In addition to which, there
is mostly a uterus, vagina, testis, penis (spi-

culum), and vesicula seminalis. The ova
are round or oval, often furnished with a
shell, wrhich sometimes has a lid.

The development of the ova of the En-
tozoa takes place according to two methods :
either the yolk-mass undergoes the ordi-
nary process of segmentation, ultimately
forming the embryo; or large transparent
embryonal cells 'form in the yolk, the
latter not becoming segmented, but under-
going subdivision and diminution in size,
the growth of the embryonal cells con-
tinuing at the expense of the yolk-mass
until it is entirely consumed; the entire
mass then becomes covered with a delicate,
sometimes ciliated, epithelium, and forms the
embryo.

In numerous instances, after this primary
stage of development — the embryonal-ce'l
condition — has been attained, the embryo
does not become directly developed into a
form of being resembling the parent ; but
the intermediate larval or nurse forms, de-
scribed under GENERATIONS, ALTERNATION
OF, are produced from it by a non-sexual
process ; and ultimately, forming the last
stage of the metamorphosis, beings resem-
bling the parent, and furnished with sexual
organs, are produced. The discovery of
the alternation of generations has brought
to %ht the fact that many of the supposed
species of Entozoa are only the larval or
nurse forms of the true species ; and that
many of these forms only complete their
stages of metamorphosis when placed under
particular circumstances, i. e. in the bodies
of different animals, or in different organs
of the same animal.

The following arrangement may serve as
an index to the articles upon the Entozoa,
contained in this work :—

Order 1. Sterelmintha. Alimentary canal
often absent, or not distinct ; when pre-
sent, with a single orifice only, and
branched.

Earn. 1. CESTOIDEA (tape-worms). Body
strap-shaded, distinctly or indistinctly
divided into transverse joints; male
and female organs in each joint ; ali-
mentary canal indistinct or none.

Bothriocephalus, Tcpnia.

(Cystica) Nurse or larval forms of
Cestoidea : —

Cysticercus, Ccenurus, Echinococcus.

Earn. 2. TREMATODA. Body mostly flat-
tened; alimentary canal distinct,

EOSINE.

[ 292 ] EPENDYMA VENTRICULORUM.

branched ; male and female organs in
each individual.

Amphistoma, Diplozoon (Diporpa),
Distoma (Cercaria), Gyrodactylus.
Fam. 3. ACANTHOCEPHALA. Body flat-
tened, transversely wrinkled, becoming
cylindrically distended by the imbibi-
tion of water ; sexual organs in separate
individuals.

Echinorhyn ch us.

Order 2. Ccelelmintha. Alimentary canal
present, distinct, simple, with two orifices.
Fam. 4. NEMATOIDEA (round worms). Body
cylindrical, hollow ; sexes separate.

TrichocephaluSj FilariatA8caris( Oxy-
urus), Anguittula, Trichina, Anchylo-
stoma, Dochmius.

See ACEPHALO CYSTS and ENOPLIPJE.

BIBL. Siebold, Vergl. An.; Rudolphi,
Entoz. Hist. Nat. and Entoz. Syn. ; Dujardin,
Helminth. ; Bremser, Icones Helminth. ;
Owen, TodcFs Cyd. ii. Ill; Blanchard, Ann.
Sc. Nat. 3 s6r. Zool. vii. viii. x. xi. xii. ;
Diesing, Helminth. ; Yogt, Zool. Brief e ;
Beneden, Vers cesto'ides, 1850 ; id., Vers in-
testin. (27 pi.), and Icon. d. Helm. 1860 ;
Pagenstecher, Trematod-Larven ; Kiichen-
meister, Parasiten, 1881; Cobbold, Para-
sites ; Eberth, Nematoden, 1863 ; Schneider,
Nematoden (22 pi., 130 cuts), 1866 ; Da-
vaine, Entozoaires, 1877 ; Linstow, Helmin-
thol 1878; Wagener, Cestoden (22 pi.);
Leuckart, Menschl. Parasit. 1881.

EO'SINE. — A beautiful rosy dye, having
the composition of tetrabromo-fluorescine,
produced by the action of bromine upon
fluorescine dissolved in acetic acid. It is a
rapid staining agent, dyeing the protoplasm
of nucleated blood-corpuscles, but not the
nuclei ; it is also useful in the distinction of
nerve-structures.

BIBL. Gibbes, Hist.-, Dreschfeld, Jn. Anat.
xi.; Watts, Dirt.Ckem.; "Wissozky, Schultze's
Arch. 1877, xiii. 479.

EOS'PHORA, Ehr.— A genus of Rota-
toria, of the family Hydatiuaea.

Char. Eyes three, sessile — two frontal,
one cervical; foot forked. Freshwater.
Among Conferva.

There are three species.

E. digitata (PI. 43. fig. 28 : fig. 29, teeth).
Body conical, hyaline, not auricled, toes
one third of the foot in length. Length

BIBL. Ehr. Infus. p. 451.

EOZO'ON,Dawson.— A Foraminifer,with
hyaline and tubular shell-structure, and
very numerous irregular chambers. Out-
spread for about a square foot, and heaped
up nearly half as high, with diminishing-
size, it occurs imbedded in the Lauren-
tian and other old limestones of Canada,
Bohemia, &c. The chambers,' stolons,
pseudopodial passages, and canal-system are
represented by delicate casts of magnesian
silicates, such as pyroxene, serpentine, and
loganite ; sometimes by calcite, like that of
the shell itself. In the former case they
can be separated by the removal of the cal-
careous shell in slices of the marble, by
dilute acid.

Layer after layer of Eozoon formed banks,
thus constituting a large proportion of the
massive limestones; and the sarcode was
mostly replaced by hydrous silicates, such
as have been injected into the pores of Si-
lurian and other fossils, and just as glauco-
nite takes the place of the soft parts of
Foraminifera, Polyzo'a, &c. in existing
seas. The Eozoonal limestone, with its
associated muds, sands, and shingle, has
been folded, crushed, and variously meta-
morphosed, often in a high degree.

BIBL. Logan, Dawson, Carpenter, and
Hunt, Quart. Jn. Geol. Soc. 1865, xxi. 45,
and 1867, xxiii. 257; Carpenter, Intel
Observ. 1865, vii. 278; and Microscope, 1881;
Giimbel, Sitz. layer. Akad. 1866; Zirkel,
Mineralien, 1873 ; Mcebius, Eoz. Can. 1878 ;
King and Rowney (disputing the organic
character of Eozoon), Proc. Roy. Irish
Acad. ser. 1. x. and ser. 2. i. ; & An Old
Chapter fyc. 1881.

^ EPEI'RA, Walck.— A genus of Arach-
nida, of the order Araneidea.

E. diadema (the common autumnal gar-
den-spider) forms a favourable object for
the examination of the various structural
peculiarities of spiders, — as the integument
(PI. 6. rig. 4) ; the legs, with their hairs and
claws (tig. 8, a, 6); the toothed hairs at
the end of the feet (fig. 8) show very clearly
the transition from the hairs to the claws,
in fact, that the latter are mere modifica-
tions of the former ; also the lung-plates
(figs. 9, 9 b) ; the spinnerets, the web (fig.
11), &c.

BIBL. Walckenaer, Apteres ; Brandt,
Medizin. Zool. ; Walker, Brit. Spid. (Itay
Soc.}.

EPEN'DYMA VENTRICULORUM is

EPHEBE.

[ 293 ]

EPHEMERID^E,

the name given to a layer which coats
those portions of the ventricles of the brain
which are not connected with the prolonga-
tions of the pia mater — as the floor of the
fourth ventricle, the aqueduct of Sylvius, the
floor and the sides of the third ventricle,
the fifth ventricle, with the roof, the ante-
rior and posterior cornua, and a considerable
part of the inferior cornua of the lateral
ventricles. It consists of delicate ciliated (?)
pavement epithelium, situated either imme-
diately upon the cerebral substance, or upon
an intermediate layer of connective tissue, or
of a soft homogeneous or granular mass. The
cells are nucleated, and vary in diameter
from 1-960 to 1-490" ; they sometimes con-
tain pigment.

The ependyma is considered by many
anatomists a portion of the arachnoid
membrane. Corpora amylacea are often
met with beneath it ; sometimes also brain-
sand.

BIBL. Kb'lliker, Mikr. Anat.

EPHE'BE, Fr.— A genus of Collema-
ceous Lichens, usuaUy described in an imper-
fect state as species of Stigonema, a supposed
genus of Algae. E. pubescens has a hairy,
branched, cartilaginous frond, covering the
surface of damp subalpine rocks with a
blackish-brown felt ; the branches are subu-
late, and the plant is dioecious ; some speci-
mens have the branches swollen into spindle-
shaped receptacles, in which are imbedded
numerous conceptacles, opening by a pore,
lined with clavate thecce, each containing
eight unisepate spores; other specimens
bear spherical or subo void subapical^cmcfrrt,
in which are immersed spermoyonia, de-
hiscing by a pore, containing numerous
linear basidia (sterigmata), supporting very
slender oblong sperniatia. Two supposed
species of Stigonema, Ag. (atrovirens and
mammillosiini), have been found in fruit as
perfect Ephebce, by Thwaites. According
to Flotow, forms of this Lichen have been
described under many names by Kiitzing
and others.

BLBL. Bornet, Ann. Sci. Nat. 3
ser. xviii. 155, pi. 7 ; Berk, and
Br. Ann. N. H. 1851, vii. 188 ;
Nylander, Syn. pi. 2. figs. 1 & 7 ;
Leighton, Lich. Fl. G. B. 10.

EPHELO'TA, Wright.— A
genus of marine Infusoria, fam.
Actinophryina (Acinetina, Clap,
and Lachm.), resembling Podo-
phrya, but the tentacles pointed
instead of capitate, and forming a
wreath or circlet.

2 species. On Sertidaria, and in the
mouths of shells containing hermit-crabs.

BIBL. Pritchard, Inf. p. 562; Wright,
Ed. Neiv Phil. Jn. 1858, p. 7.

EPHEM'ERA, Linn.— A genus of Neu-
ropterous Insects, of the family Ephemeridae.

Char. Wings four ; posterior filaments
three ; head of larva with cornua.

The larva and pupa are favourite micro-
scopic objects, for showing the dorsal vessel,
the circulation, branchial plates, &c. See

EPHEME'RE^E.— A family of inoper-
culate Acrocarpous (terminal-fruited) Mos-
ses, usually dwarf, caespitose, or gregarious.
Stem almost simple. Leaves more or less
oval or lanceolate, slightly concave, pellucid,
with or without nerves. Cells of the leaves
parenchyma to us, lax in all parts, elongate,
not papillose. Capsule mostly obliquely
apiculated.

British Genus.

Ephemerum. Calyptra campanulate. In-
florescence monoecious or dioecious (anthe-
ridia on a very short special branch situated
near the base of the stem).

EPHEMER'ID^E(May-flies).— Afamily
of Neuropterous Insects.

Characterized by the minute size of the
antennae ; the unequal size of the anterior
and posterior pairs of wings (the latter of
which are in some absent) ; the membra-
nous and almost obsolete mouth ; and the
elongated jointed setae at the posterior end
of the body.

Body long, slender, and soft ; head small,
trans verse-trigonate ; eyes large, nearly oval,
lateral ; ocelli three, forming a triangle be-
tween the eyes ; antennas three-jointed, the
two basal joints thick, the third forming a
long slender seta. Abdomen consisting of
nine joints; the terminal the longest, and
gradually narrowed and furnished at the
apex in both sexes with two or three long,
slender, many-jointed filaments. Legs
slender ; anterior pair in the males porrected,
much elongated, with the tibiae and tarsi

Fig. 198.

Ephemera Swammerdamii. Nat. size.

EPHEMERID^E.

[ 294 ]

EPIDERMIS.

appearing soldered together; basal tavsal
joint very minute, tarsi five-jointed, termi-
nated in the fore legs of the male by two
oval pulvilli ; in the four posterior legs tarsi
short, five-jointed, and terminated by a large
oval pulvillus, and a single broad notched
claw.

These insects must have been seen by
every one, rising and falling on the wing,
near the banks of rivers and pools ; in the
perfect state their life lasts but a few hours,
whence the name. The ova are deposited
in the water. The larva bears a considerable
resemblance to the pupa, from which it
differs in the absence of rudimentary wing-
covers ; they are frequently mistaken for
each other.

The pupa of the common Ephemera (md-
gatd) (PI. 35. fig. 15) has the prothorax as
broad as the head, transverse-quadrate ; the
mesothorax gibbous ; the head rather small,
with two short horns in front, and two horny
toothed mandibles, furnished at their upper
angles with a long curved horn ; labrum
flat, membranous, ciliated, and with the
angles rounded ; maxillae small, membra-
nous, curved, pointed at the tip, and inter-
nally setose ; maxillary palpi four-jointed,
and not extending beyond the front of the
head ; labium large, membranous, four-lobed,
and furnished with a broad tongue j labial
palpi broad and three-jointed; antennas
about twice the length of the head, many-
jointed and ciliated ; legs short, broad, and
much compressed ; tarsi two-jointed, with a
terminal hook ; abdomen nine-jointed, the
six basal segments being furnished on each
side with a pair of elongated, rather narrow,
gills or branchial plates («), with long, nar-
row filaments at their edges, through each
of which a trachea extends to the tip, the
tracheae from each contiguous pair of fila-
ments uniting near the base, and then
running to the large tube which traverses
the centre of each plate ; there are in all
24 branchial plates. At the end of the
abdomen are three elegantly feathery setae.

The pupa of Clceon — another of the
Ephemeridae, in which the imago has two
wings and two abdominal setae — resembles
that of Ephemera, but has the antennae as
long as the body.

The larvae and pupae of the Ephemeridae
may be most easily caught in the ring-net,
and are admirably adapted for showing the
dorsal vessel, with its valves, and the circu-
lation. They are perhaps best preserved in
glycerine, or solution of chloride of calcium.

BIBL. Westwood, Introd. ; Pictet, Ins.
Newopt., 1843 ; Curtis, Brit. Entom. 703 ;
Pritchard, Micr. lllustr. 61 (pi. 2. fig. of
Clceon pupa).

EPHEM'ERUM, Ham™.— A genus of
Ephernereae(AcrocarpousMo8ses),including
part of Phascum of authors.

BIBL. Wilson, Hryol. Brit. 27; Berkeley,
Brit. Mosses, 304.

EPHIP'PIA.— The winter-ova of the
Entomostraca. See EGGS and ENTOM os-

TBACA.

EPIBLE'MA. See the EPIDERMIS of
Plants.

EPICLIN'TES, Stein.— A genus of Hy-
potrichous Infusoria, fam. Oxytrichina.
(Stein, Inf. ii. ; Kent, Inf.)

EPICO'C'CUM, Lk.— A genus of Stilba-
cei (Hyphomycetous Fungi), parasitic upon
dead leaves, &c., consisting of very minute
gregarious tubercles, somewhat linearly
arranged, reddish or purplish, containing
numerous spherical, smooth or roujrhish,
reticulate spores. E. neglect um is adnate
to a short pedicel. When mature the
stroma is quite covered with spores about
1-2000" in diameter. Uredo Equtseti,
1 Br. Flora,' is an Epicoccum with smooth
spores.

One species of Epicoccum, which grows
on decaying vegetable matter, produces a
form of what is commonly called Blood-
rain. It was developed on the calico cur-
tains of a shower-bath during the preva-
lence of cholera in 1834, and excited some
consternation, as it was supposed to be
connected with the malady. It occunvd a
short time afterwards in considerable abun-
dance on a water-melon.

BIBL. Desmaz. Ann. Set. Nat. 2 se>. xvii.
95 ; Berk, and Broorne, Ann. N. H. 1850,
v. 406, Crypt. Bvt. 312 ; Fries, Summa Veg.
476.

EPIDER'MIS OP ANIMALS. See SKIN.

EPIDERMIS OF PLANTS.— There are
few parts of the structure of vegetables that
have given rise to more discussion than the
epidermal cells and the tissue they consti-
tute. Even the term epidermis has become
to a certain extent equivocal, since it is
used by some authors in the sense in which
cuticle is used by others, and vice versa. Our
object here will be to state as briefly as
possible the most remarkable facts, and the
explanations which are received by the best
authorities.

If we gently scrape the surface of the
leaf of a hyacinth, or other soft-leaved bul-

EPIDERMIS.

[ 295 ]

EPIDEKMIS.

bous plant, and seize a little piece of the
ragged edge with a pair of fine forceps, we
may strip off large pieces of what appears,
to the naked eye to be a thin homogeneous
pellicle. When this is placed under the
microscope, it is found to be composed of a
layer of cells united firmly together by their
sides like stones in a pavement, but loosely
connected with the subjacent tissue, which
adheres here and there to the detached strip
in ragged patches. The firm continuous
layer of cells is what botanists call the
epidermis of plants. Such a layer of cells
clothes the entire surface of the higher
plants, from the Flowering plants down to
those in which the organs, such as the
leaves, are reduced to mere layers of cells
like the epidermis itself, as in the Mosses.
In a very young and delicate state, such as
we find it clothing the surface of organs
still concealed in buds, or of young ovules
in the ovary, it has been called epiblema.
A rather more solid form, but still soft and
devoid of thickening layers, such as exists
on the surface of the growing parts of root-
lets &c., is called epithelium. Both these
terms appear useless, and only calculated
to confuse the student still more than the
use of the words epidermis and cuticle,
which already endanger misconception from
the very different characters of the struc-
tures called by those names in animal
organs.

When a layer of epidermis is macerated
in nitric acid, a thin pellicle, destitute of
cellular structure, becomes detached in
sheets from the outer surface of the plate of
epidermal cells; this is the cuticle (fig. 199)

Fig. 199.

Cuticle of a cabbage-leaf, removed by the action of nitric acid.

P, hairs ; F, orinces corresponding to stomata.

Magnified 250 diameters.

of botanical anatomists, concerning which
much misconception has prevailed. As
epidermis advances in age it becomes con-
siderably solidified, especially on evergreen
leaves, and on shoots of shrubs &c. which
remain green for a lengthened period, such

as Aucuba and Viscum. In most cases, how-
ever, the epidermis of structures belonging
to the stem disappears about the same time
as the leaves fall off, and is replaced by the
suberous layer of the bark structure, which
change is evident externally by the surface
assuming a brown colour, the subjacent
tissue containing chlorophyll being hidden.
The green colour of parts clothed with epi-
dermis depends upon the subjacent tissue
showing through the transparent epidermis,
the cells of which are usually colourless, and
filled with watery contents.

When sections are made perpendicularly
to the surface of any fully developed leaf,
but above all of those of leathery texture,
the walls of the cells next the external
surface are found much thicker than the
rest, this thickening extending more or less
down over the contiguous side walls. When
such sections are treated with sulphuric acid
and iodine, the greater part of the thick-
ness, from without inward, of this outer
wall is stained yellow, while the rest of the
walls assume the blue colour ordinarily
taken by cellulose with these reagents.
Some authors suppose that the whole of
this yellow part corresponds to the cuticle
above mentioned: but such is not the case;
if such a section is boiled or macerated for
a long time in solution of caustic potash,
then washed well with water and treated
with tincture of iodine, the thick upper
wall also assumes the blue tint, and, more-
over, a laminated structure becomes evident
in it, showing that it is produced by the
deposition of secondary layers inside the
cell. The true layer of cuticle (which is
dissolved off by the continued action
of potash) is really extremely thin
in almost all cases. The true nature
of this thickening of the outer walls
is well illustrated by the epidermis of
Viscum (Mistletoe), which remains
upon the shoots for many years ; here
several layers of cells subjacent to the
original superficial stratum become
involved in the process of solidifica-
tion, and their cavities completely
filled up by the secondary deposits.
The true structure of the enormously
thick epidermal layer of old shoots,
as brought out by the action of potash, is
seen in the example of PI. 47. fig. 26. The
true cuticle is sometimes of considerable
thickness, as in the leaves of Cycas (PI. 47
fig. 28). The thickening layers of the epi-
dermal cells are true SECONDARY DEPOSITS.

EPIDERMIS.

[ 290 ]

EPIDERMIS.

The nature of the cuticle, is yet uncertain ;
some regard it as a kind of excretion har-
dened over the surface, others as the per-
sistent original outer wall of the parent-cells
of the epidermal cells, metamorphosed che-
mically where exposed directly to the action
of the air (in a manner analogous to that in
which the parent-cell membranes become
converted into a gelatinous investment of
the filaments of Confervae, the cells of Pal-
mellaceae, &c.). This seems borne out to
some extent by the change of condition of
the consolidated part of the outer walls,
coloured yellow by sulphuric acid and iodine ;
but it is unknown whether there is here a
real chemical change, or merely an infiltra-
tion capable of being removed by the action
of potash (see SECONDARY DEPOSITS).

Although the cellular plants possess no
true epidermal layer, the superficial cells
form a kind of cortical structure in the
Lichens and larger Algae ; and in the lower
Algae the cells of the filaments &c. compo-
sing the fronds bear some resemblance to
epidermal cells in structure, insomuch that
they have laminated walls (partly produced
by the persistence of those of the parent
cell after cell-division), with the outer layer
possessing much of the physical character
of the cuticle of the higher plants. As just
mentioned, the gelatinous sheaths of the
lower Algae must be regarded as a kind of
cuticle, and as produced by gradual disor-
ganization of the outer layers of membrane
while cell-development and the formation
of new layers is going on within. For
further discussion of the nature of the
thickening layers of epidermis, see INTER-
CELLULAR SUBSTANCE.

The epidermis and its appendages offer a
great variety of points of interest to the
microscopist. The epidermis of those grow-
ing parts of the higher plants which are
exposed to the air is not absolutely con-
tinuous and without orifices like the epi-
dermis of roots, but is perforated with
myriads of breathing-pores or STOMATA
(fig. 200, s) as they are called. These con-
sist of gaps left by the separation of the
superficial epidermal cells at their meeting
angles, the interspace between them being
guarded and more or less filled up by
(usually) a pair of cells, situated just be-
neath the outer orifice, and having a slit-
like passage between them.

flairs, scales, thorns, stings, and the
Tirious forms of (/lands of plants, are ap-
pendages of the epidermal structure, being

Epidermis from petal of the balsam, with stomata, 8.
The epidermal cells here have elegantly sinuous

side walls.
Magnified 200 diameters.

produced by the peculiar development of
particular cells or groups of cells of this
superficial layer.

We have already alluded to the different
conditions of the epidermis in different parts
of plants. The delicate layer coverino; young
organs in buds becomes very variously deve-
loped as these attain the complete conditions.
On the leaves and shoots the epidermis be-
comes consolidated by secondary deposits,
and this in greatest proportion on leathery
or woody leaves, &c.,such as those of ever-
greens, shrubs, and trees. Remarkable ex-
amples of this may be found in the leaves of
the Proteaceae, Cycadacese, the Holly, Box,
&c. (woody), and in the Aloes, Cactaceae,
Oleander, Hakea, Ficrn, &c. (leathery). In
all cases the solid character of foliage de-
pends almost exclusively upon the character
of the epidermis by which the leaves are
clothed. The epidermis of the outer scales
of the winter-buds of trees is remarkably
thick. The thickening layers are some-
times found on the walls of the stomatal
cells and adjacent cells bounding the inter-
cellular cavity, forming the pseudo-struc-
ture called a cistome (see STOMATA).

The epidermis of petals and similar deli-
cate organs never acquires much solidity;
but the outer walls often become elevated
more or less above the surface, producing a
minute papillosity of the epidermis, which
gives the peculiar glistening appearance.
When this elevation goes still further, villi

EPIDERMIS.

[ 297 ]

EPIDERMIS.

or short hairs are produced, rendering the
surface velvety (see HAIRS).

The side walls of epidermal cells are
sometimes flat faces of tolerably regular
geometrical figures, such as cubes, parallelo-
pipeds, hexagonal prisms, &c. ; but not un-
frequently they are very sinuous, and then,
when the epidermis is seen from above, it
does not look like ordinary parenchyma,
with square, rectangular, or hexagonal tes-
sellse, but the component cells are fitted
together so as to present lines, which, when
regular, might be described by the heraldic
terms scallopped. wavy, indented,£c. (PL 47.
fig. 15), and when less regular resemble
ro ughly the lines of j oint in the old-fashioned
puzzle-maps of children (fig. 200). Such
forms of the epidermis are frequently found
on petals, on the leaves of Ferns, on those
of Hellebore, &c., and constitute very pleas-
ing microscopic objects; especially as, in
addition to the lines, the stomata at the
angles add to the elegance of the pattern.

The cuticle on many petals, as those of
the Daffodil, and on leaves, as those of the
genus Helleborus, Dianthus, &c., when the
epidermis is viewed from above, exhibits
elevated strise running in various ways over
the surface, sometimes converging in the
centre of each cell, in other cases running
in tortuous lines over the surface, con-
tinuous beyond the boundaries of the indi-
vidual cells. A similar condition of the
cuticle occurs upon the HAIRS of many
plants, especially of Cruciferte, Ranuncu-
laceae, Boragineee, &c. This condition is
evidently analogous to the equally myste-
rious states of the outer membrane of POL-
LEN-GRAINS and SPORES, where points,
ridges, reticulations, &c. of the same kind
constantly occur.

The stomata are found on both surfaces of
many leaves of delicate structure, but most
abundantly on the lower surface ; in other
plants they occur exclusively on the lower
face ; in floating leaves they exist only on
the upper face ; while on submerged leaves
none at all occur, and the epidermis here
has no very distinct difference from that of
young roots. The characters of STOMATA
are spoken of more at length under that
head, as also those of HAIRS, SCALES,
STINGS, THORNS, GLANDS.

The cuticular layers of the epidermis
often contain deposits of wax upon or with-
in the tissues. De Bary distinguishes four
kinds : — 1, heaps of granules in several
layers, or of delicate needles, as in Euca-

lyptus, Acacia, grasses, &c.; 2, a simple
layer of -grains, in Allium cepa, Brassica
okracea, &c. ; 3, a layer of rods perpendi-
cular to the surface, as in Musacece, Saccha-
rum, &c. ; and 4, a membranous wax-layer
or crust, as in Sempervivum, Thuja, and
Taxus. Some of the wax-grains are not
recognizable until the tissues are heated to
212°, when they form drops.

The epidermis of the Equisetacese and
the Grasses is remarkable for the deposition
of silica, apparently in the walls of the cells
of the epidermis, to such an extent and so
equably, that the whole of the organic
matter may be removed by heat or acids,
and a perfect skeleton of the structure be
obtained, composed exclusively of silex,
exhibiting the boundary lines of the epi-
dermal cells and the stomata (the dentate
side walls, with the stomata arranged in
linear series, are described in most micro-
scopic books in a very curious manner, from
an old paper by Sir D. Brewster). Prepa-
rations 01 this structure are obtained by
treating little pieces of the wall of the fistu-
lar stem with strong nitric acid, to remove
alkalies, and then burning them until quite
white on a slip of platinum or very thin
glass. These should be mounted in Canada
balsam.

In the Equiseta, the siliceous films thus
obtained are covered with minute spines,
presenting somewhat the dotted appearance
of the valves of the Diatomacese.

The seeds of many plants are clothed
with an epidermis of remarkable character,
the cells containing spiral fibres ; this oc-
curs in the ACANTHACE^:, in COLLOMIA,
SALVIA, &c., and is further treated under
those heads and under HAIRS and SPIRAL
STRUCTURES.

BIBL. Mohl, Vegetable Cell, 1852, Linncea,
xvi. 401, Verm. Schrift. 260, Ann. Sc. Nat.
2 ser. xix. 201, ibid. 3 ser. iii. 158, Sot. Zeit.
v. 497 (1847); ibid. vii. 593, 1849; Schlei-
den, Wiss. Bot. 3 ed. 335 (Principles, 70) ;
Brongniart, Ann. Sc. Nat. xviii. 427, 2 ser.
i. 65; Link, Elem. Phil. Bot. i. 83; Wigand,
Inter cellular- Substanz u. Cuticula, 1850 j
Karsten, Bot. Zeit. vi. 729, 1848; Cohn,
Linncea, xxiii. 337, 1850 ; Hartig, Entwickl.
der Pft. 1843, Ann. Sc. Nat. 3 s<§r. i. 352 ;
linger, Bot. Zeit. v. 289, 1847; Garreau,
Ann. Sc. Nat. 3 s6r. xiii. 304 ; Mulder and
Harting, Mulder's Phys. Chem.\ Goldmann,
Bot. Zeit. vi. 857, 1848; Schacht, Pflan-
zenzelle, 89, 1852 ; Wiesner, Techn. Mikr.
1867 ; Leitgeb, Denkschr. Wien. Ak. 1865,

EPIPYXIS.

[ 298 ]

EPITHELIUM.

xxiv. 253 ; Thomas, Jahr. iviss. Hot. iv. 33 ;
Pfitzer, ibid. vii. 561, and viii. 17 ; De Bary,
JBot.Zeit. 1871; Sachs, Sot. 1874; Henfrey-
Masters, Sot. 1878.

EPIP YX'IS, Ehr.— A genus of Flagellate
Infusoria, of the family Dinobryina.

Char. Fixed by a pedicle ; eye-spot
absent ; no cilia nor appendages.

E. utriculus (PL 30. tig. 50). Carapace
urceolate ; body filled with yellowish gra-
nules ; on Conforms ', length 1-650".

Probably the young state of Dinobryon
sertularia, like which it contains a disk-
shaped nucleus.

BIBL. Ehrenb.J»/ttf.l23; Kent,Jn/t«.400.

EPISTY'LIS, Ehr.— A genus of Infu-
soria, of the family Vorticellina.

Char. Pedicle rigid, not contractile,
simple or branched ; all the bodies of the
animals of the same form.

Claparede and Lachmann refer the species
of Opcrndaria to this genus.

Stein has pointed out the occurrence of
the encysting-process in the species of this
genus ; and indicates the presence of a lid-
like discoidal process, protrusible from the
orifice, as in Vorticella, furnished with
vibratile cilia ; but this does not occur in
all the species admitted by Ehrenberg. The
species are numerous, and mostly attached
to aquatic animals or algae. Clap. & Lachm.
admit 19 species.

E. anastatica (PI. 30. fig. 51 a, c). Body
small, conical, not plicate, anterior margin
large and projecting; pedicle dichotom-ms,
smooth, or covered with minute or foreign
bodies; entire length 1-144 to 1-14"; of
single body, 1-288".

E. grandis. Body large, broadly campa-
nulate; pedicle decumbent, slender, smooth,
laxly branched, not jointed, forming large
tufts ; length of body 1-140 to 1-120".

E. vegetans (ANTHOPHYSA Miillet'i, Duj.).

BIBL. Ehrenb. Infus. 279 ; Stein, Inf. ;
Claparede and Lachmann, Inf. 107 ; Tatem,
Mic. Tr. 1868, 31 ; Kent, Inf. 700.

EPIT'EA, Fr. See UBEDINEI, PHRAG-
MIDIUM, and MELAMPSOKA.

EPITHE'LIUM. — The membranous
layer lining the various internal cavities,
and covering the internal free surfaces of
animal bodies, as the mucous canals and
cavities, and their involutions forming the
glands and ducts, the serous cavities, the
vessels, &c.

It consists of one or more layers of nu-
cleated cells, the form and arrangement of
which are very variable. They are either

round, polygonal, spindle-shaped, cylindri-
cal, or conical ; and are united by a small
quantity of intercellular substance. They
contain a clear or granular nucleus, with
one or more nucleoli. In some instances
they contain granules of black pigment or
melanime.

Three kinds of epithelium are usually
distinguished ; but intermediate forms are
also met with.

Pavement- or tessellated epithelium.
This consists of roundish, oval, or polygonal
flattened ceils, about 1-2000 to 1-500" in
diameter, and containing nuclei with nu-
cleoli. It occurs upon the Surface of the
serous and synovial membranes ; the mem-
brane of the aqueous humour, the choroid,
the capsule of the lens, the retina, and the
conjunctiva of the ball of the eye ; the ca-
vity of the tympanum ; the lower half of
the pharynx, the oesophagus, the end<>rar-
dium ; some veins ; many glands and ducts,
as the racemose, the sudoriparous and ceru-
minous glands ; the hepatic ducts ; the
vagina and female urethra; the bladder,
uterus, pelvis, and tubules of the kidneys;
and the air-cells of the lungs. In the ai-lc-
ries and many veins the cells are spindle-
shaped.

Cylindrical epithelium. In this form the
cells are either cylindrical, conical, or pyra-
midal, about 1-1000" in length, and so
situated that the axis of the epithelial scales
or cells is at right angles to the surface upon
which they are placed. Sometimes the sub-
jacent cells are of a rounded form.

Cylinder-epithelium is met with in the
mucous membranes, inLieberkiihn's follicles,
and the ducts of the gastric as well as those
of all other glands opening into the intes-
tine ; in the lachrymal and the mammary
glands ; the male urethra ; the vas defereus ;
the vesiculse seminales, the prostatic ducts,
with Cowper's and the uterine glands.

Ciliated epithelium. In this the form
and arrangement of the cells is much the
same as in the last; but their free ends
are furnished with numerous vibratile cilia
(PL 49. fig. 13).

Ciliated epithelium occurs in the larynx,
trachea, and bronchi ; the nares and pha-
rynx above the level of the base of the nasal
bones, and the cavities opening into them ;
the inner surface of the membrana tympani,
the Eustachian tube ; the uterus, the Fallo-
pian tubes ; the lachrymal sac and nasal
duct; the palpebral conjunctiva; and the
ependyma.

EPITHELIUM.

[ 299 ]

EQUISETACE^E.

In most epithelia, the cells and their
nuclei are readily distinguished ; but in
others, especially those of the vessels and
serous membranes, staining with magenta,
&c., is required to render the nuclei dis-
tinct, and silvering to bring out the cell-
boundaries. (See STAINING-.)

In many cases, intervals are left between
the epithelial cells, usually at the points
where several cells meet ; these are called
stomata. They are often connected with
the lymphatic system. See STOMATA.

The epithelium covering the outer sur-
face of the body forms the epidermis or
cuticle.

Further particulars of the special forms
of the cells are given under the heads of
the organs or tissues in connexion with
which the epithelia are found.

BIBL. Kolliker, Mikr. An. and Handb.
d. Gcwebel. ; Valentin, Wagner s Handb. d.
Phys., art. Flimmerbewegung and Epiihel. ;
Herile, Allgemein. An. ; Todd and Bow-
man, Phys. ; Frey, Histoloyie, 1876, 153 and
the full literature.

EPITHELIUM OF PLANTS. See EPI-
DERMIS of Plants.

EPITHE'MIA, Brebisson.— A genus of
Diatoinaceas. •

Char. Frustules single, attached by a part
of the surface to other bodies ; valves with
transverse or slightly radiant striae, some of
them not resolvable into dots.

Frustules prismatic, quadrangular, mostly
curved, sometimes slightly undulating in
the side view ; one face of front view (that
by which they are attached) flat or con-
cave, the other convex and broader than the
former, so that the transverse section forms
a trapezoid. Between, or corresponding
with the transverse striae, which are not
resolvable into dots, are often transverse
rows of dots or depressions.

The species are numerous. Freshwater
and marine. Rabenhorst describes 21 Eu-
ropean. Conjugation has been observed in
three of them.

E. turgida (PI. 16. fig. 32 : «, side view ;
5, front view). Front view oblong, slightly
dilated towards the middle; side view some-
what convex, gradually attenuated towards
the very obtuse ends. Freshwater ; length
1-240". In conjugation, PI. 10. fig. 6 a, b,
c, d, e.

E. cjibba (PI. 51. fig. 6). Straight ; in-
flated in the middle on each side in front
view ; valves gibbous in the middle on one
side; freshwater and fossil; length 1-140".

BIBL. Kiitzing, Bacillar. 33, and Sp.
Alg. 1; Smith, Brit. Diatom, i. 13; Ra-
benhorst, Sp. Alq. i. 62.

EPOCH'NIUM, Lk.— A genus of Toru-
lacei (Hyphomycetous Fungi), forming a
stratum over larger fungi or dead twigs,
consisting of a mycelium of irregularly
branched and anastomosing filaments, which
bear, on short lateral brancblets, oblong or
globular septate spores, which soon fall off
and lie among the mycelium-threads.

E. fungorum is very common, forming a
dark-green stratum over Thelephorce; E.ma-
crosporoiditim was found by Berkeley on a
dead twig, apparently of red currant.

Sphceria Epochnii, B. & Br., has been
found on Epochnium fungornm ; and it is
very probable that it is the perfect state of
a conidiiferous mycelium.

BIBL. Berk, in Brit. Flora, vol. ii. pt. ii.
352 ; Ann. N. H. i. 263, pi. 8. fig. 14.

EQUISETA'CEJE and EQUISETUM.
— This is a very distinctly characterized
family of Flowerless Plants, consisting of a
single genus, the Equiseta, or Horse-tails,
which are immediately recognized, when
one species is known, by their peculiar aspect
and habit of growth. The stems and branches
are alike tubular, and present in almost all
cases a rather coarsely (per-
pendicularly) streaked sur-
face. The stems appearing
above ground are shoots
from a creeping under-
ground stem (fig. 201),
which differs from the
erect stems in being of
a deep brown colour and
solid, in giving off root-
fibrils, and sometimes in
being covered with hairs.
The erect stems are either
barren or fertile; in the
barren stems the joints be-
come gradually thinner
upwards from a certain
point, at last tapering off
to an obtuse apex; the fer-
tile stems bear a kind of
club-shaped head, resem-
bling in SOme degree the Equisetum arvense.
male cones of Coniferous One half of
trees, or more particularly nat- size-
those of some Cycads (fig. 201). These
club-shaped bodies are the fruits or heads
of sporanges.

The anatomical structure of the rhizome
and shafts present some interesting points.

Fig. 201.

EQUISETACE^.

[ 300 ]

EQUISETACE.E.

In the solid rhizome the centre is occupied
by cellular tissue of tolerably strong texture ;
outside this, as seen in a cross section,
stands a circle of air-canals, each surrounded
by a ring of vascular bundles ; next comes
a complete circle of vascular bundles com-
posed almost wholly of annular ducts ; be-
tween this vascular ring and the outside
lies parenchyma like that in the centre,
traversed by another concentric circle of
air-canals ; and immediately beneath the
epidermal cells there exists a layer of com-
pact blackish-brown parenchymatous cells.
When the rhizome is coated with hairs,
these are formed by development of the
epidermal cells into slender tubular pro-
cesses. Tracing the solid rhizome up to-
wards the points where the erect stems
arise, the central cellular substance is gra-
dually lost, and the outer portions are mo-
dified in their arrangement. The distribu-
tion of the air-canals and the vascular bun-
dles varies ; in some cases, the peculiarities
are even regular enough to afford specific
characters. The surface is clothed by an
epidermis composed of elongated cells often
elevated into papilhe, and especially re-
markable for the quantity of silica deposited
in their walls. This epidermis is studded
with variously formed stomata usually
arranged in double lines ; and the forms of
the epidermal cells and stomata are per-
fectly preserved in the siliceous ash which
remains after burning off the organic sub-
stance from a portion of this EPIDERMIS,
offering a curious microscopic object. Be-
tween the epidermis and the central cavity,
in a cross section lie — first, a layer of thick-
walled elongated cells, within which, in the
angular-stemmed species, comes a circle of
masses, usually crescentic, of cellular tissue
containing chlorophyll. Next come usually
two concentric rings of air-canals, those of
the inner circle being individually sur-
rounded by annular ducts ; and, moreover,
in some species a circle of 6-10 vascular
bundles separates the inner from the outer
circle of air-canals j the structure of the
bundles is variable, exhibiting annular, spi-
ral, and reticulated ducts. The inner circle
of air-canals lies in the parenchyma which
bounds the central cavity. At each joint
this cavity is cut off by a diaphragm com-
posed of three layers, in the intermediate
of which, of brownish cellular tissue, lies an
anastomosing ring, where all the vascular
bundles coalesce and give off branches to
the sheath (and branches when present).

The club-shaped fruit-spikes consist of a
central axis forming the last joint of the
stem, on which are attached numerous
mushroom-shaped groups of spoj-anyes, the
stalks of each adhering to the central axis,
so that we only see the upper side of the
cap externally (figs. 202, 203). This has
an angular border ; and the adjacent spo-
ranges being very close, the outer ends of
these bodies cause a tessellated appearance
of the whole in the earlier stages of de-
velopment. As the sporanges ripen, they
separate more from each other ; and when
one is removed (fig. 204), it is seen to
possess a number of little pouch-like cases
under the overhanging outer portion and
round the stalk ; these pouches burst by a
perpendicular slit inwards, and discharge
the spores.

Fig. 202.

Fig. 203.

Fig. 205.

Equisetum arvense.

Fi<r. 202. Fruit-spike. Magnified 3 diams.

Fig. 203. A spike halved vertically. Magn. 3 diams.

Fig. 204. A stalked group of sporanges removed from

preceding. Magn. 25 diams.
Fig. 205. A spore with elaters uncoiling. Magn. 200

diams.

The spores of the Equiseta are very re-
markable, and unlike any other known ve-
getable structure. They are roundish cells,
with apparently only one coat j for the outer
coat splits up into four thread-like pro-
cesses (elaters), thickest and rather clubbed

EQUISETACEJE.

C 301 ]

ERIODERMA.

at their free ends. While the spore remains
in the sporange, these fibres are rolled round
the spore ; but when the spores are dis-
charged, the coiled fibres uncurl (fig. 205),
and assist in scattering the spores, their
elasticity causing them to spring out.

The Equiseta possess only this one kind
of spore ; and the germination is analogous
to that of the Ferns, in which likewise only-
one kind of spore exists. The membrane
of the spore pushes out a pouch-like pro-
cess, which after a time becomes cut off
by a septum ; the end-cell grows on and
multiplies in both directions, until a lobu-
lated prothallium is produced ; on this arise
archeyonia and antheridia, in distinct indi-
viduals, the archegonial prothallia being
larger than the antheridial, and resembling
in all essential respects those produced on
the corresponding structure in the FEBNS.
The antheridia are formed on the ends or
the margins of the male prothallia. The
spermatozoids are larger than those of other
Cryptogamia ; they have 2 or 3 coils, the
posterior thickened portion being furnished
with an appendage, supposed to consist of
an undulating membrane.

After the fertilization of an archegonium,
the germ-cell contained in it becomes deve-
loped as an embryo, and a new Equisetum-
stem of the ordinary structure springs up
(fig. 206), forming a creeping rhizome with

Fig. 206.

Equisetum arvense.

Young stem arising from a prothallium.
Magnified 15 diameters.

upright fistular shafts, resembling the parent
plant from which the spores were derived.
The family Equisetaceae is represented
in existing vegetation by a single genus,

containing only herbaceous plants. The
Equisetaceee of former ages were far more
important as regards size.

BIBL. Francis's British Ferns, 5th ed.
1855 ; Thuret, Ann. So. Nat. 3 ser. xi. 5 ;
Milde, Bot. Zeit. viii. 448, and x. 537,
Linncea, xxiii. 545 ; Hofmeister, Vergleich.
Unters. 1851, Verh. k. Sachs. Akad. d. Wiss.
iv. 123; Bischoff, Erypt. Geivachse, Heft 1,
27, pis. 3, 4, 5, Botan. Zeit. xi. 97 ; Prings-
heim, Bot. Zeit. xi. 241; Sanio, Bot. Zeit.
xiv. 177, xv. 657 ; Milde, Nova Acta, 1867,
xxxv. ; Nageli and Leitgeb, A%.ife^.iv.lS67;
Janczewskry, Bot. Zeit. 1872, 420 ; Tieghem,
Ann. Sc. Nat. 5 ser. xiii. ; Sachs, Bot. 389.

EREBONE'MA, Rom.— A supposed ge-
nus of Kiitzing's family Leptoiniteae. Some
imperfect filamentous organism, probably
belonging to a Fungus.

BIBL. Romer, Deutschl.Alg. 70; Kiitzing,
Sp. Alff. 157.

EREM^'US, Koch.— A genus of Ori-
batidae (Acarina).

Char. Cephalothorax without lamellas ;
tarsi with heterodactyl claws. Allied to
Hoplophora. (Murray, EC. Ent. 222, fig.)

ERE'MOSPILERA. See CHLOBO-

SPHJERA.

ERE'TES, Wemeck.— A genus of Infu-
soria, of the family Cryptomonadina.

Char. Those of Phacelomonas with a
carapace.

One species : the spores of an Alga ?

BIBL. Werneck. Ber. Berl Ak. 1844,
377.

ERGOT and ERGOT^E'TIA. See CLA-

VTCEPS.

ERIN'EUM, Pers.— A supposed genus
of Fungi, really consisting of abnormal de-
velopments of the cells of the epidermis of
the trees upon which they are supposed to
be parasitic; or galls, produced by the action
of Phytoptidae. They occur chiefly upon
the Anientacese, Aceraceae, and RosaceaB
(Apple-trees, Plum-trees. &c.).

See TAPHRINA.

BIBL. Fries, Syst. Mycol iii. 521 ; Berke-
ley, Lindleifs Veg. Kingdom, art. Funyaks ;
Murray, EC. Entom. 331.

ERIODER'MA, Fee.— A genus of tro-
pical Lichens, tribe Lecanorei, externally
resembling the Peltigerae ; consisting of a
green membranaceous thallus, spreading
from the centre, hairy above, and with
woolly anastomosing nerves beneath. Apo-
thecia marginal, with hispid hairs on the
margin underneath.

BIBL. Fee, Crypt. 145, pi. 34. fig. 2.

ERIOSOMA.

[ 302 ]

ERYSIPHE.

ERIOSO'MA. See APHIDJE.

ERIOS'PORA, Berk. & Br.— A genus
of Sphaeronemei (Stylosporous Fungi), de-
scribed (E. leucostoma) as forming minute
brown spots upon dead leaves of the bulrush.
The conceptacles are globose, and collected
in numbers on the stroma, bursting by a
single common (white-bordered) pore to
discharge the spores (stylospores), which
are filiform and very slender, and arise in
fours from a sporophore. (See CONIOMY-

CETES.)

BIBL. Berk, and Br. Ann. N. H. 1850,
v. 455, pi. 11. fig. 1.

ERUPTIONS, CUTANEOUS.— The scales,
crusts, scabs, contents of vesicles, pustules,
&c. formed in various diseases of the skin,
usually consist of epidermic cells alone,
more or less flattened or otherwise altered,
or of these with the ordinary products of
inflammation. Granules of soot are fre-
quently found, in London at least, mixed
with the above elements ; and these were
once regarded as the microzymes of small-
pox. Fungi exist in the crusts of some
skin -diseases, as FAVUS, &c. The itch-
insect, SARCOPTES, must not be forgotten,
nor DEMODEX. See PABASITES.

ERVIL'IA, Duj. (jEgyna,G\. & Lachm.).
— A genus of Infusoria, of the family
Ervilina.

Char. See the family. Marine.

E. legumen = Euplotes monostylus, E.
(PI. 30. fig. 52 ; b, side view). Body with
two ventral contractile vesicles ; length
1-650 to 1-420".

3 other species.

BIBL. Duj. Infus. 455; Clap. & Lachm.
Inf. 288.

ERVILI'NA, Duj. (Dysterina, 01. &
Lachm.). — A family of Infusoria.

Char. Body oval, more or less depressed,
entirely or partly ciliated, with a tail-like
foot, usually also with a persistent mem-
branous carapace.

Genera :

Carapace present.

Composed of two distinct valves Iduna.

Composed of two united valves.
Valves united behind and below only ... Dysteria.

Valves united all down the back Ervilia.

Carapace absent Huxleyia.

Duj ar din questions whether lire-centrum,
E., does not belong to this family.

BIBL. Duj. Infus. p. 454 j Clap. & Lachm.
Infus. p. 278.

ERY'SIPHE, Hedw. fil.— A genus of
Pyrenomycetes (Ascomycetous Fungi),
consisting of little mildews overgrowing the

leaves of living plants, mostly Dicotyledons.
The mycelium is formed of slender ramified
filaments, which spread and form an en-
tangled web over the epidermis of the in-
fected plant, sending into the substance
sucker-like processes or hausteria, by which
nourishment is obtained from the juices of
the leaf. From the creeping mycelium arise
numerous upright short-jointed filaments,
the last one or more of the cells or joints
of which swells so as to render the erect
filament clavate or moniliform. These ex-
panded cells become detached with the
greatest readiness, and, when they fall upon
the supporting leaf, germinate and produce
new mycelium threads. In this state the
Erysipha cannot be distinguished from the
^enus Oidium; and as this state is succeeded
in most cases by the true conceptacle of
the genus Erysiphe, the Oidia (such as
O. Tuckeri, the Vine-fungus), which grow
under the same circumstances, but do not
produce conceptacles, are regarded by most
authors as imperfect ErysipluB. (See Oi i > n M ,
PI. 26. figs. 12-14.) When the mycelium
of an Erysiphe is developed late in the year,
it seldom produces any thing but the ovate
cells (conidia)', but if developed early in the
summer, the mycelium grows at certain
points into denser white patches (receptacles,
Lev.), from which arise the concept tides,
which are fertilized by pollinodia, as in
Eurotium. These are small globular sacs,
composed of a double layer of cells ; from
the base of the outside of the sac arise a
number of radiating filaments, simple or
branched (appendides, Le>.), while in its
interior are developed one or many sacs,
(a-sci) sporanges, Le"v.), in each of which
are produced mostly eight sporidia. In
addition to the above, a third form of fruit
occurs, in which the conidium becomes
transformed into a sac (pycnidiwni) filled
writh minute spores. Tulasue has figured
a second form, apparently of conidia, in
Phyllactinia guttata.

LeVeiHe", in an elaborate essay on this
genus, has subdivided it into six genera,
which may perhaps be better taken as sub-
genera, and may be distinguished in the
following manner : —

Conceptacles with one ascus.

Appendicles dichotomously branched. . . Podospheeria.
„ floccose Sphcerolheca,

Conceptacles with many asci.

„ aciculate TJiyll actinia.

„ uncinate UndnnJa.

„ dichotomously branched... Microsphceria.
„ floccose Erysiphe.

ERYSIPIIE.

[ 303 ]

EUACTIS.

Podospluzria. The Hawthorn-blight and
the Plum-blight belong1 to this division.

Splicer otheca. The Rose-mildew, E. pan-
nosn, auct., belongs to this group, and is
distinguished from E. macularis, Wallr.
(S. Castagnei, J. Lev.), the Hop-mildew, by
the appendicles of the former being white,
while those of the latter are coloured. The
mycelium of the rose-mildew seems to be
the saaie thing as Oidiumleucoconium,~Desm..
The similar structure of the Hop-mildew
has been described and figured (from Dr.
Plomley's drawings) in the Trans, of the
Horticultural Society. He was the first to
discover the conversion of one of the oidioid
cells into pycuidia.

Pkyllactinia. E. guttata, Schlecht., com-
mon on the hazel and other trees and large
shrubs, is distinguished from the other
forms of Phyllactinia by having a bulbous
base to its appeudicles, which contain 2 to
4 sporidia.

Uncinula. E. adunca, Schlecht., is re-
ferred here ; its distinctive character is the
existence of the hooked appendicles. Found
on willows. E. bicornis, Lk., occurring
upon maples £c., has eight spores.

Microsphceria. E. penicillafa, occurring
on Viburnum Opulus, &c. Several species
occur in this country, of which one of the
best-known is M. penicillata. The charac-
ters of the appendicles, which are dichoto-
mously branched at the tip, are the same as
those of Podosphceria ; but there are many
asci, instead of one only.

Erysiphe. E. Pisi, Grev., is E. Martii
of Leveille, distinguished by its globose,
many-spored asci and the simple or irre-
gularly branched appendicles. E. tortilis,
Lk., has coloured appendicles ten or more
times the length of the conceptacle. It
grows on Cornm sanguined, the Dogwood
tree. E. communis, Lev., is not very well
characterized ; it has coloured appendicles,
which are only twice or thrice as long as
the conceptacle ; the asci vary from four to
eight, as do also the spores contained in
each. This species grows on a great variety
of herbaceous plants, Ranunculacese, Corn-
posits, LeguminoseB, Cruciferae, Polygo-
nacens, &c.

Perhaps a doubt might be admitted whe-
ther the above subdivisions really represent
more than six species of this genus.

BIBL. Leveille, Ann. Sc. Nat. 3 ser. xv.
100, pis. 6-11 ; Berk., Hook. Br. Fl. ii. pt. 2.
325; 2>. Hort. Soc. London, ix. 61 ; Greville,
Sc. Crypt. Fl. pis. 134, 164. figs. 2, 296 ;

Tulasne, Compt. Rendus, 18-53; Ann. Sc. Nat.
4 ser. vi. 299, and Carpologia, i. 1860; Cooke,
Handbook, 645 ; Taylor, M. M. Jn. 1875,
xiii. 121 ; De Bary and Woronin, Beit. z.
Morph. 1870; Sachs, Bot. 312.

See also OIDIUM.

ERYTHR^E'US, Duges.— See ANTSTIS.

ESCHAR'IDzE.— A family of Cheilosto-
matous Polyzoa; containing the genera
Lepralia,) Umbonula, Porella, Escharoides,
Smittia, Phylactella, Muwonella, Palmicel-
laria, and Retepora.

ESCHAROI'DES, Smitt.— A genus of
Cheilostomatous Polyzoa, fam. Escharidse.

2 species ; deep water. (Iliucks, Polyzoa.
336.)

ESPAR'TO. — The bast-fibres of a grass,
Lygeum spartum (Stipa tenacissima, Linn. ;
MakrocUoa, Kunth), a coarse fibrous ma-
terial, extensively used in the manufacture
of paper. The fibres are shorter than those
of most allied substances : and the epider-
mic wavy margined cells are so short as to
render the distinction of this material toler-
ably easy.

It occurs extensively in the south of Eu-
rope, in North America, and in the centre
and south of Spain.

BIBL. Henfrey-Masters, j#o£.400; Wiesner,
Techn. Mikr. 225 (fig.).

ESTHE'RIA, Ruppell and Straus-Diirck-
heirn (Cyztcus, Audouin ; Isaura, Joly).

A bivalved phyllopodous Entomostracon,
having 24 pairs of foliaceous limbs, and
ovate valves, horny, delicate, concentrically
ridged, bearing from 7 to 80 lines of growth,
with intermediate reticulation or other
sculpturing.

26 species are known, from fresh and
brackish waters of warm climates ; and
more than 20 fossil, Devonian to Tertiary.

BIBL. Baird, Zool. Proc. 1849, 87; 1852,
30 ; 1859, 232 ; 1860, 188 and 392 ; Rupert
Jones, Fosa. Estherice (Pal Soc.}, 1862; E.
Grube, Arch. f. Naturgesch. 1853, xix., and
1865, xxxi.

EUACTIS, Kiitz.— A genus of Oscillato-
riacere (Confervoid Algae), of the tribe Rivu-
larieae, consisting of little, hard, solid, elastic,
mostly hemispherical bodies, from 1-2 to 2'"
in diameter, growing upon stones in the sea
or rivers, &c. ; concentrically zoned, core-
posed of radiating, flagelliform, repeatedly
sheathed filaments, the sheaths of which are
open and slit above (PI. 8. fig. 16), but con-
nected together side by side, so as to form
a tough gelatinous mass, not becoming in-
crusted with carbonate of lime. To this

EUASTRUM.

[ 304 ]

EUCHLANIS.

genus Kiitzing refers Rivularia plicata, atra,
and perhaps applanata of Harvey. These
plants are interesting on account of the
fibrous decomposition of the gelatinous
sheaths.

BIBL. Harvey, Brit. Mar. Alg. 222, pi.
26 A (Rivularw) ; Kiitzing, Sp. Alg. 339 ;
Tab. Phyc. cent. ii. pis. 74-82.

EUAS'TRUM, Ehr.— A genus of Des-
midiaceae.

Char. Cells single, compressed, deeply
divided into two segments, which are gene-
rally pyramidal and furnished with circular
protuberances, lobed or sinuated at the mar-
gins, and emarginate at the ends.

Ralfs describes twenty-one British spe-
cies, of which the following are the most
common.

* Segments deeply lobed; end lobe distinct,
cuneate, partly included in a notch be-
tween the lateral lobes.

E. vei-rucosum (PI. 14. fig. 14). Rough ;
segments three-lobed, lobes broadly cuneate,
with a shallow notch ; length 1-207".

E. oblongum (PI. 14. fig. 15). Smooth,
oblong ; segments five-lobed ; lobes cuneate ;
emarginate; length 1-156".

E. crassum. Smooth; segments three-
lobed, subquadrilateral ; end lobe cuneate ;
length 1-190 to 1-130".

** Segments sinuated; end lobe exserted and
united with the basal portion by a distinct
neck.

E. didelta (PI. 14. fig. 16; 17, empty
cell). Segments with inflated base, inter-
mediate tubercles, and notched and scarcely
dilated ends; side view, four shallow lateral
lobes, and one at each end ; length 1-185".

*** End lobe indistinct ; frequently a process
or acute angle at the corners of the ter-
minal portion.

E. elegans. Oblong ; ends emarginate,
pouting, and rounded ; length 1-890 to
1-420".

Conjugation has been observed in several
species ; the sporangia are spherical, with
conical tubercles, or acute or obtuse spines.

BIBL. Ralfs, Brit. Desmid. 78; Raben-
horst, Fl. Alg. iii. 179.

EUCAM'PIA, Ehr. — A marine organism,
allied to the Desmidiaceae, among which it
is placed by Kiitzing, whilst Smith refers it
to the Diatomaceae.

It forms articulated, arcuate or spiral,
fasciaeform, microscopic fronds, composed

of hyaline wedge-shaped frustules, with
yellowish granular contents. The joints
shrink in drying, and are destroyed by heat.
The markings consist of dots.

E. zodiacus (PI. 50. fig. 10). Frustules
with a median excavation on each side ;
valves elliptical ; length 1-710".

E. britannica. Frustules not excavated :
length 1-380".

E. striata. Valves circular ; endochrome
green.

BIBL. Ehrenb. Abh. Berl. Ak. 1839, 125;
Kiitzing, Sp. Alg. l$l,Bacillar. pi. 21. fig. 21 ;
Smith, Br. Diat. ii. 25 ; Stolterforth, Jn. M.
Soc. 1879, ii. 835.

EUCERTYD'IUM, Ehr.— A genus of
Polycystina.

E. ampulla (PI. 39. fig. 25, front view ;
fig. 26, under view).

See POLYCYSTINA.

EUCHLAN1DOTA, Ehr.— A family of
Rotatoria.

Char. Rotatory organ multiple, or divided
into more than two lobes ; a carapace pre-
sent.

The carapace forms either a testa or a
scutellum ; various appendages are present,
representing either straight bristles, curved
bristles or hooks, minute horns — so-called
respiratory tubes or antennae,— and in one
genus a frontal hood.

The eleven genera are thus distinguished :

Eyes absent; foot forked

Eyes present.
Eye single (cervical).
Foot styliform.

Carapace depressed Monostyla.

„ prismatic Alastigocerca.

Foot forked.

Carapace open beneath Euchlanis.

„ closed beneath.

Carapace with horns Salpina.

,. without horns Dinocharis.

Eyes two (frontal).

Foot styliform Monocerca.

„ forked.

Carapace compressed or prismatic. Colurus.
„ depressed or cylindrical.

Head without a hood Metopid-ia.

„ with a hood Slephanops.

Eyes four ; foot forked Squamella.

BIBL. Ehrenb. Inftts. p. 455.

EU'CHLANIS, Ehr.— A genus of Rota-
toria, of the family Euchlanidota.

Char. Eye single, cervical ; foot forked ;
carapace cleft or open on the ventral surface.
Aquatic.

Ehrenberg describes six species, to which
Gosse adds three.

E. triquetra (PI. 43. fig. 30; fig. 31, teeth).
Carapace very large, with a dorsal crest;
foot without setae ; length 1-48".

EUCRATEA.

[ 305 ]

EUGLENA.

BIBL. Ehrenb. Infus. 461 ; Gosse, Ann.
N. H. 1851, viii. 200.

EUCRAT'EA, Lamx, (Scruparia).—K
genus of Cheilostomatous Infundibulate
Polvzoa, of the family Eucratiidae.

E. chelata (PL 36. fig. 24), the only species.
Parasitic upon Fuci, crabs, and stones.
(Hincks, Polyzoa, 11.)

EUCRA'TIID^E (Scrupariadse). — A
family of Cheilostomatous • Infundibulate
Polyzoa.

Distinguished by the unjointed polyzoary
and the uniserial cells. Polyzoary usually
loosely adnate. Five genera :

Eucratea (Scruparia). Erect, branched,
branches arising from the horn-shaped cells
above or below the oblique orifice.

Hippothoa. Creeping, adherent, irregu-
larly branched or netted, branches arising
from the sides of the cells.

Salpinyia (PI. 36. fig. 25). Erect,
branched; cells elongated, with trumpet-
shaped processes at the base, orifice oblique,
lateral.

Anguinaria (sEtea). Cells tubular, scat-
tered, arising from a creeping, adherent
thread.

Beania. Cells erect, scattered, with a
double spinous keel on one side, and arising
from a creeping, adherent, branched thread.

BIBL. Johnston, Br. Zooph. 288; Busk,
Mar. Polyz. 28; Gosse, Mar. Zool. ii.
12 ; Hincks, Polyzoa, 11.

EUCYTHE'RE, Brady (Cytheropsis,
Sars). — A genus of marine Entomostraca,
fam. Cytheridae.

2 species.

BIBL. Brady, Linn. Trans. 1868, p. 429.

EUDEN'DRIID^E (Tubulariidse, pt.,
Johnst.). — A family of Hydroid Polypi.
Characterized by the branched stem, and
the terminal naked polypes, with a single
whorl of tentacles surrounding the base of
a trumpet-shaped proboscis.

1 genus : Eud,endrium.

EUDEN'DRIUM, Ehr.— A genus of Hy-
droid Polypi, fam. Eudendriidae (Tubula-
riidas, Johnst.).

Char. Those of the family.

7 British species.

E. ramosum (Tubularia ram.} Johnst.) is
common on oyster-shells, &c.

BIBL. Hincks, Brit. Zooph. 79; Johnstone,
Brit. Zooph. 46.

EUDORI'NA. See PANDORINA.

EUGLE'NA, Ehr.— A genus of Infu-
soria, of the family Astasiaea.

Char. Fiee ; a red eye-speck, a tail-like

process, and a single flagelliform filament ;
freshwater.

Many species, or rather forms, are distin-
guished by Ehrenberg and Dujardin. They
are often present in vast numbers in pools,
&c., rendering them green or red, and form-
ing a brilliant pellicle upon the surface.

In the free condition the Euglence swim
about in the water, not apparently by the
help of the flagelliform filament, which
seems to be often deficient, but by the con-
tractile action of the whole body, the changes
of form and movements of which may be
roughly compared to those of a leech when
crawling sluggishly over the surface of a
glass. The Euglence present many points of
resemblance to the lower Algae, especially
Protococcus, like them varying in colour
from green to red, and, moreover, passing
through a resting stage, encysted in a kind
of cell-membrane, which is sometimes gela-
tinous, transparent, and spherical, some-
times rather horny, and polygonal in form.
The encysted forms occur commonly aggre-
gated together into indefinite frond-like
masses ; and the individuals multiply by
division into two, four, &cv in this quiescent
stage. The frond-like groups may be found
in autumn, and even under the ice* in winter,
while the active forms abound most in spring,
in fine weather. Carter has published some
elaborate observations on the organization
of these and allied forms, which we have
notspacetoenteruponhere. (SeeAsTASLEA.)
We can only notice two or three of the forms.
E. viridis (PI. 31. fig. 2 a, b). Fusiform
when extended ; head narrowed, short ; tail
conical, short (not cleft) ; green, hyaline at
the ends; length 1-1150 to 1-240".

E. pyrum (PI. 31. fig. 1). Body, when
extended, oval, turgid, pyriform, obliquely
furrowed, green ; tail nearly as long as the
body, acute; length 1-1150 to 1-860".

E. longicauda, Phacus longic. D. (PI. 31.
figs. 3 & 63). Depressed, elliptical or oval,
frequently twisted on its long axis, green,
with longitudinal striae ; tail as long as the
body, hyaline, subulate ; length 1-280
1-120".

E. acus (PL 31. fig. 4). Fusiform, slender,
subulate, straight, green in the middle ;
head attenuate, somewhat truncate, hya-
line ; tail very acute, hyaline ; length 1-570
to 1-216".

BIBL. Ehrenb. Infus. 104; Dujardin,
Infus. 358 ; Morren, JRubef. d. Eaux. Brux.
1841 ; Carter, Ann. N. Hist. 1856, xviii.
115; and 1857, xx. 21 ; Kent, Inf. 379.

EUGLENIA.

[ 306 ]

EUPLOTES.

EUGLE'NIA, Duj. (Infusoria). See

ASTASLSSA.

The essential character of this family is
the presence of a contractile integument;
this is probably of little importance, as in
many cases the nature of the integument
has been shown to depend upon season,
locality, and stage of development.

EU'GLYPHA, Duj.— A genus of Rhi-
zopoda.

Char. Free ; single ; carapace membra-
nous, transparent, resisting, elongate-ovoid,
urceolate, covered with rows of tubercles
or depressions ; orifice toothed ; expansions
numerous, simple.

This genus appears unnecessarily sepa-
rated from Dffiugia, E.

E. tuberculata (PI. 30. fig. 53). Carapace
covered with oblique or longitudinal rows
of rounded tubercles. Freshwater ; length
1-280". Sometimes posterior spines are
present.

E. alveolata (PI. 30. fig. 64). Carapace
covered with polygonal depressions, in re-
gular oblique rows. Freshwater; length
1-280". Posterior spines also present.

See DIFFLUGIA.

BIBL. Dujard. Inf. 251 ; Carter, Ann. N.
Hist. 1865, xv. 290.

EUMERID TON, Kiitz. — Consolidated
with MERIDION.

EUNO'TIA, Ehr.— A genus of Diato-
maceae.

Char. Frustules free, single or binate,
quadrilateral ; linear or linear-oblong in
front view, curved or concavo-convex in
side view ; valves with terminal puucta
(nodules?) and transverse or slightly ra-
diating striae, but no canaliculi. Fresh-
water and fossil. Allied to Ejnthemia.

Many of the species have undulations or
ridges upon the convex surfaces ; striae re-
solvable into dots, but in some species diffi-
cult to detect ; transverse section of frustule
trapezoidal.

Kiitzing describes forty-four species;
Smith admits seven as British.

E. tetraodon (Himantidium tetr., K.) (PI.
61. fig. 27 : 0, side view ; 6, front view).
Frustules with four ridges ; striae distinct ;
length 1-570".

E. monodon (Himant. monodon, K.). Side
view lunate, no ridges, slightly constricted
near the obtuse ends ; striae obscure ; length
1-800".

E. triodon. Ridges three ; ends attenuate,
rounded; striae obscure; length 1-500".
BIBL. Kiitzing, Batill. 36, and Sp. Alg.

4 ; Smith, Brit. Diat. i. 15 ; Ralfs, Ann. N.
H. 1844, xiii. 459.

EUNOTOGRAMMA, Weisse.— A genus
of fossil Diatomaceae.

Char. Front view as in Anaulus; side
view lunate, with undulated dorsal and
ventral margins.

E. tri-, quinque-, septem-, et novemlociilata.
Side view divided by 2, 4, 6, or 8 transverse
septa into 3, 5, 7 or 9 loculi. Russia.

BIBL. Pritchard, Infus. 860; Weisse,
Bull St. Petersbotirg, xiii. 278.

EUODIA, Bailey.— A genus of Diato-
maceae.

Char. Frustules areolar or granular, side
view lunate.

3 species: 2 fossil, 1 recent. Perhaps
Goniothecia.

BIBL. Bailey, Pritchard's Infus. 852;
Greville, Micr. Tram. 1861, 67.

ELTPLEURIA, Arn.— A genus of Diato-
maceae.

3 species : New Zealand and Africa (Icha-
boe guano).

BIBL. Arnott, Qu.Mic.Jn. 1858, vi. 89.
EUPLO'TA, Ehr.— A family of Infu-
soria.

Char. Body surrounded by a carapace ;
two distinct alimentary orifices, neither of
which is terminal ( = Oxy trichina with a
carapace).

Locomotive organs consisting of cilia,
hooks, claws, or styles. Dujardin states
that the carapace undergoes diffluence like
the substance of the body.
The genera are thus distinguished :—

Cilia,
claws, or
hooks

teeth

-v

1 Head distinct ...Dixcocephalus.

> NQ dutinct he&d.Himantophorus.

JoTty^es. I Mouth with teeth CMamidodon.

Cilia, claws, and styles present Euplotes.

Dujardin includes this family in his Ploes-
conina.

BIBL. Ehrenb. Infus. 374; Dujard. Inf.
429.

EUPLOTES, Ehr. (Plcesconia, Duj., for
the most part). — A genus of Infusoria, of
the family Euplota, E.

Char. Furnished with cilia, styles, and
hooks ; teeth absent.

The species are very numerous.

E. patella, E. (Plcesconia pat., D.) (PI. 31.
fig. 5 : «, under view ; b, side view). Cara-
pace a testa, oval or suborbicular, slightly
truncated in front, margins extending be-
yond the depressed body ; dorsum raised or
bossed with fine radiating striae ; cilia form-

EUPODISCUS.

[ 307 ]

EURYCERCUS.

ing a curvilinear series j freshwater ; lengtl
l-i>88 to 1-216".

E. cimex, E. (Coccudina cimex, D.).

E. charon, E. (Plcesconia charon, I).).

E. vannus, E. (PL vannus, D.) (PL 31
fig. 6).

E. monostylus, E. (Ermha legumen, D.
(PI. 30. fig. 52).

BIBL. Ehrenb. In/us. 377 ; Duj. 7w/ws
435 ; Stein, Infus. 158.

EUPODIS'CUS, Ehr.— A genus of Dia-
tomaceee.

Char. Frustules single, disk-shaped, cir-
cular, without internal septa; valves fur-
nished with tubular or spiniform processes.
Marine and fossil.

The processes are so easily broken off,
that the apertures corresponding to the
points of attachment are generally alone
seen. The valves appear either distinctly
areolar, the depressions being large ; granu-
lar, from their being minute ; or striated.

Two groups are recognizable :

a. Eupodiscus proper. Valves areolar or
striated.

E. argus (PI. 16. fig. 30 : a, side view ; b,
front view). Valves slightly convex ; pro-
cesses three ; diameter 1-156".

E. sculpttis, Sm. (PI. 16. fig. 31). Valves
striated, central striae forming a quatrefoil ;
processes two ; diameter 1-770 to 1-400".

b. Aulacodiscus,~E,. Valves granular; pro-
cesses very short, their bases connected with
the centre" of the valve by a furrow.

E. crux (PI. 50. fig. 43). Diameter 1-380".

E. Petersii. Processes four, with larger
granules at their bases. Diameter 1-380".

BIBL. Ehrenb. Abh. Berl 1839 ; id. Ber.
1844, 73, 1845, 361 ; Smith, Brit. Diat. i.
24 ; Kiitzing, Sp. Alg. 134 j Shadbolt, Qu.
Mic. Jn. ii. ; Roper, 1858, ibid. vi. ; Gre-
ville, Mic. Trans. 1863, 73, (Aulacodiscus)
1864, pp. 9, 82, 87, 1865, p. 26, 1866, pp. 5, 80.

EUPO'DIUM.— A genus of Marattia-
ceous Ferns. Exotic.

EURO'TIUM, Lk.— A genus of Pyreno-
mycetes (Ascomycetous Fungi), on the dis-
tinct nature of which great doubt is thrown
by the recent observations of De Bary. E.
herbariorum of authors is a mildew, common
upon decaying or preserved fruits, plants
imperfectly dried for herbaria, &c., forming
a whitish or yell ow crust, composed of inter-
woven mycelium filaments, which are deli-
cate when young, but become thickened and
often coloured with age. Upon these are
produced globular conceptacles or peridia,
from 1-15 to 1-20'" in diameter, composed

of a distinctly cellular membrane, enclosing
little sacs or asci containing several minute
sporidia. According to De Bary, these con-
ceptacles are produced upon the mycelium
of Aspergillus, under certain unknown con-
ditions ; and the ordinary fructification of
Aspergillus is only a basidiosporous form of
the same plant which produces an asco-
phorous form in the Eurotium fruit. He
states that he not only found them grow-
ing upon the continuations of the same
branched mycelium filament, but that he
has raised Aspergillus, which fruited, from
the spores both of Aspergillus fruits and the
sporidia of Eurotium -, Eurotium could not
be obtained from Aspergillus spores. The
connexion between these forms is regarded
as analogous to that between Oidium and
Erysiphe. The fruit of Eurotium is a sexual
product, and originates as follows. The
ends of certain branches of the mycelium
coil up like a cork-screw, becoming more
closelv approximated, until at length they
come into contact, and form a cylindrical or
conical mass, marked externally by the
spiral lines of conjunction of the turns of
the filament. From the base of this mass
thin branches sprout, running up over it, one
of them fusing with its apex, forming an
antheridium or pollinodium, and producing
fertilization. After fertilization, the young
perithecia become segmented, the segments
forming shoots, which branch, the termina-
tions forming the asci or parent cells of the
sporidia. The ripe sporidia often exhibit a
curious form, like little cylinders with a con-
cavo-convex cap applied over each : these
appear to be the two halves of the dehiscent
outer membrane (exospore) ; for in the ger-
mination of perfectly globular forms the
mycelium filaments break through the outer
tough coat, like a pollen-tube from the inner
coat of a pollen-grain. The sporidia are
about 1-350'" in diameter, and of a light
yellow colour in mass. The dimensions &c.
of Eurotium, like those of Aspergittus, seem
to vary with the external conditions.

Eurotium Rosarium, Greville (Sc. Crypt.
Fl.) = Sphceroiheca pannosa.

BIBL. Berk, in Hook. Brit. Fl. ii. pt. 2.
333 ; Greville, Scot. Crypt. Fl pi. 164. fig.
L ; Sowerby (Farinaria), pi. 379. fiX 3 •
De Bary, Bot. Zeit. xii. 425 (1854) ; Riess,
'lid. xi. p. 134, and Fresenius, p. 474
1853).

' EUR YCEROUS, Baird (Lynceus, in part,
Vfiill.). — A genus of Entomostraca, of the
rder Cladocera, and family Lynceidse*

EUTERPE.

[ 308 ]

EXPECTORATION.

Char. Subquadrangular (in side view) ;
abdomen very broad, flattened, densely ser-
rated ; beak blunt, slightly curved down-
wards. Freshwater.

E. lamellatus (PL 20. fig. 39). Shell olive,
ciliated on the anterior ventricose margin,
arched behind ; beak rather blunt and short;
superior antennae terminating in six short
spines, each with a fine seta or bristle ; an-
terior branch of inferior antennae with five
long filaments — one from the end of the first
and second joints, three from the third, as
also a small spine; posterior branch with
three long filaments at the end of the last
joint, the first and second each with a short
spine only.

It generally lives at the bottom of the
vessel in which it is kept.

BIBL. Baird, Brit. Entom. p. 123.

EUTER'PE, Glaus,— A genus of Cope-
poda.

1 species: Ireland. (Brady, Copepoda,
Ray Soc. ii. 22.)

EUTREP'TIA, Perty.— A genus of Fla-
gellate Infusoria.

Char. Free, ovate, or pyriform, green;
swimming or creeping ; flagella two, equal ;
an anterior red eye-spot.

E. viridis. Length ajo"- Pond-water.

BIBL. Perty, Kl. Lebensf. 168; Kent,
Inf. 41C.

'EVADNE, Love"n.— A genus of Entom-
ostraca, of the order Cladocera, and family
Polyphemidas.

Char. Abdomen short, scarcely projecting
from the shell ; head not distinct from the
body ; marine.

E. Nordmanni (PI. 19. fig. 30). Colour-
less, excepting the eye.

Forms part of the food of the herring.

BIBL. Love'n, Wiegmanris Archiv. 1838,
Bd. i. 143; M.-Edwards, Crust, iii'. 390;
Baird, Brit. Entom. 114.

EVER'NIA, Ach.— A genus of Lichena-
ceous Lichens, tribe Ranialinei; cosmopo-
litan in its range ; recognized by its flat-
tened, flaccid, laciniate, white or grey thal-
lus, lateral apothecia, and simple spores.
Two species : E. furfuracea (E. Hot. pi. 984)
and E. prunastri (E. Sot. pis. 859 & 1353)
occur in Great Britain.

BIBL. Nvlander, Sun. 283; Leighton,
IAch. PL G.B. 81.'

EXCIP'ULA, Fr.— A ^enus of Sphsero-
nemei (Stylosporous Fungi), forming horny
tubercles on dead stems and leaves, finally
opening by an entire orbicular aperture.
The stylospores are elongated, lanceolate or

fusiform; and long hair-like processes are
sometimes mixed with the sporophores
which line the disk. Four British sp«-ri«'s
are recorded : E. fusispora and E. strif/nxa-
of Fries, and E. macrosticha. and E. clifdo-
stroma of Berk, and Br. Perhaps related
to some Ascomycetous form. (See CONIO-

MYCETES.)

BIBL. Berk, in Hook. Br. Fl. ii. pt. 2.
296 ; Berk, and Broorne, Ann. N. H. 1850,
v. 456, pi. 11. fig. 2.

EXID'IA, Fr.— A genus of Tremellini
(Hymenomycetous Fungi), forming gelati-
nous, truncated black or coloured bodies on
the trunks and branches of trees. Common
in autumn and winter. Tulasne has lately
published some interesting observations on
the structure of the hymenium which
clothes the upper face. This is composed
of a densish layer of very slender filaments,
which bear at their free surface globular
cells (basidia) divided vertically into two or
four chambers ; from each of these arises a
slender process (sterigma), at the end of
which is developed a stylospore. In E. sjn'cu-
losa, spermatia were also observed in young
specimens, at the ends of very slender fila-
ments passing through the mucilaginous
layer overlying the layer of basidia. (See
DACRYMYCES, HEKNEOLA, and other genera
of TREMELLINI.)

BIBL. Berk, in Hook. Br. Fl. ii. pt. 2.
217 ; Tulasne, Ann. Sc. Nat. 3 ser. xix. 202,
pis. 11 & 12.

EXOAS'CUS. See ASCOMYCES.

EXOBASIDTUM, Wor. — The lowest
form of Hymenomycetes. E. Vaccinii is
common on Rhododendron and Vaceiniumt
causing fleshy swellings on the leaves. It
is Ascomyces carnosa, Berk.

BIBL. De Bary and Woronin, Ber. Nat.
Gesell. Freiburg, ix. 397 ; Sachs, Bot. 336.

EXOCOC 'CUS, Nageli.— Probably a Pro-
tococcus or PalmeHa.

BIBL. Nageli, Neu. Algensyst. p. 169.

EX'OGEN. See DICOTYLEDONS.

EXOS'MOSE. See ENDOSMOSE.

EXPECTORATION.— The various ob-
jects which may be found in the expectora-
tion are noticed under their respective heads,
jr those of the tissues from which they are
derived ; a list only need be given here.

Mucous corpuscles ; epithelial cells, of the
pavement, cylinder, or ciliated forms ; exu-
dation globules, or granule-cells ; pus and
pyoid corpuscles ; coloured corpuscles of the
blood ; pseudo-membranous flakes of fibiine ;
tubercle ; fatty matter in the form of glo-

EXUDATION.

[ 309 ]

EYE.

bules, rarely of crystals; earthy matters,
amorphous orcrystallme ; various substances
derived from the food, as muscular fibre,
starch-granules, cellular tissue, &c. ; ento-
zoa, or fragments of them, as portions of the
cysts or hooks of JZchinococcus; infusoria and
algae, as Monads, Bacteria, Sarcina, &c. ;
carbon and true pigment, either in the free
state or contained within epithelial cells ;
and fragments of pulmonary tissue.

The aid of the microscope in the exami-
nation of the expectoration will occasionally
throw an unexpected light upon the dia-
gnosis of disease. And it
has been shown, that by
boiling the sputa with
solution of caustic soda
and washing, the pulmo-
nary fibrous tissue may
often be detected in
Phthisis.

EXUDATION, and
EXUDATION COR-
PUSCLES. See IN-
FLAMMATION.

EXU'VIUM (exuvia;
or exuviae, plur.). — The
cast or shed skin of ani-
mals. The exuvium of
many minute animals ex-
hibits the form and struc-
ture of the skin, and the
parts upon which it is
moulded, better than
these can be discerned
in the living animals, on
account of its transpa-
rence. The exuvium of
the TRITON (PI. 49. fig.
12) exhibits the cellular
structure of the epider-
mis very beautifully.

EYE.— From want of
space, we are compelled
to assume that the reader
possesses a knowledge of
the component parts of
the eye and their relative
position, as far as can be
obtained without the use
of magnifying glasses.
These parts are generally
described in works upon
anatomy, and in most of
those upon optics.

The outer fibrous coat
of the eye is commonly
regarded as consisting of

two parts : one anterior, smaller and trans-
parent— the cornea ; the other, posterior
larger and opaque — the sclerotica. The
history of the development and the minute
structure of these prove that they must be
considered as forming a single continuous
membrane.

The cornea may be regarded as consisting
of three layers: — 1, the corneal conjunc-
tiva ; 2, the true cornea ; and 3, the mem-
brane of the aqueous humour.

The corneal conjunctiva (fig. 207, Co) con-
sists of laminated soft epithelium — the

Fig. 207.

Section of the membranes of the eye, near the ciliary processes.

Scl., sclerotica ; C, cornea; Pr. oil., ciliary process ; C a, anterior chamber ;
Cp, posterior chamber ; Co, vitreous humour ; C. P., canal of Petit ; L, lens ;
/, iris : a, conjunctiva of the cornea — epithelial layer; 6, subjacent elastic layer ;
c, fibrous layer of the cornea ; d, membrane of the aqueous humour ; e, ita
epithelium ; f, end of the membrane and its fusion with the fibres g, which
pass to the iris at i, forming the pectinate ligament ; h, venous canal ; k,
ciliary muscle arising from the inner wall I of the venous canal ; m, pigment-
layer of ciliary processes; n, that of iris ; o, fibrous layer of iris ; p, its epi-
thelium ; q, anterior wall of capsule of lens ; s, epithelium of capsule ; t, ante-
rior thickened portion of hyaloid membrane ; u, zonule of Zinn, or anterior
lamina of hyaloid membrane ; v, posterior lamina of the same; w, colourless
epithelium of the ciliary processes; w', anterior end of this epithelium;
x, conjunctiva of sclerotica ; z, posterior wall of the capsule of the lens.
Magnified 12 diameters.

EYE.

[ 310 ]

EYE.

under layer of cells elongated and placed per-
pendicularly to the surface, the middle cells
rounded, those in the upper layer forming
softer nucleated plates. Many of the latter
are furnished with larger or smaller depres-
sions, arising from mutual pressure, so as to
appear stellate in the side view. Beneath
the epithelium is a structureless layer (6),
the anterior elastic or Bowman's membrane,
consisting of the remains of the formerly
vascular layer of the corneal conjunctiva.

The true cornea (tig. 207 c), which forms
the principal part of the membrane, consists
of a substance nearly allied to connective
tissue. Its elements are pale bundles from
1-6000 to 1-3000" in diameter, with still
finer fibrillsb, united to form larger lamellar
bundles, the surfaces of which are parallel
to that of the cornea ; these are connected
with the bundles before and behind, so as
to form a coarse reticular tissue. Between
the bundles are a large number of anasto-
mosing, fusiform, and stellate lacunae, with-
in which are contained cell-structures form-
ing the corneal corpuscles. The cells under-
go fatty degeneration, partly forming the
arcw senilis j and they sometimes contain
pigment.

The cornea contains numerous fine nerves,
which ramify nearly to the surface, between
the epithelial cells.

The sckrotica (fig. 207, Scl.) or tunica
albuginea covers the posterior four fifths of
the ball of the eye ; it is a milk-white, very
firm, fibrous membrane, continuous poste-
riorly with the sheath of the optic nerve,
becoming gradually thinner in front, except
at its termination, where the tendons of the
recti muscles become fused with it. It con-
sists of connective tissue, the bundles of
which are mostly straight, intimately united
as in the tendons, forming alternating lon-
gitudinal and transverse layers of various
breadth and thickness. Mingled with the
connective tissue are numerous fine elastic
fibres, in the form of a network, with thick-
enings which indicate the remains of the
nuclei of the formative cells ; these, in the
inner portions, contain pigment. During
life, the elements of this network, in parts,
appear to involve canals with liquid con-
tents ; so that, when dried, they contain air.

The membrane of the aqueous humour
(fig. 207 d) consists of an elastic, perfectly
structureless (Descemet's) membrane, some-
what loosely connected with the cornea, and
an inner epithelial lining. Towards the cir-
cumference of the cornea, the membrane of

the aqueous humour merges into a peculiar
system of fibres, which commence near the
margin of the cornea, at the anterior surface
of the aqueous membrane (fig. 207 g) as an
extended network of fine fibres, resembling
elastic fibrillre ; this increases in thickness,
and at the very margin of the cornea the
aqueous membrane becomes lost in a tole-
raoly dense network of these fibres, which
curve around the margin of the iris (fig.
207*), some passing through the anterior
chamber, and become fused with the ante-
rior surface of this membrane and the ciliary
ligament (or muscle). These fibres form
the pectinate ligament of the iris, which is
much more distinct in some animals (as the
dog) than in man.

The epithelium (e) of the aqueous mem-
brane consists of a single layer of polygonal
cells. These become smaller near the mar-
gin of the cornea, where the membrane ter-
minates as a continuous layer ; but isolated
portions of elongated or spindle-shaped cells
are continued over the pectinate ligament
to the anterior surface of the iris.

The cornea yields chondrine on boiling,
and not gelatine.

The choroid membrane contains a large
number of blood-vessels, and abounds in
pigment. Its anterior, smaller, and trans-
verse portion / forms the iris.

The posterior portion, or proper choroid
membrane, is from 1-300 to 1-180" in thick-
ness, and extends from the entrance of the
optic nerve to near the anterior margin of
the sclerotica, where it becomes thicker,
forming the ciliary body, whence it is con-
tinued into the ins.

The choroid consists essentially of two
parts : — an outer vascular and thicker layer,
the proper choroid; and an inner deeply
coloured layer, the piymentum niyrum.
The former may again be separated into
three parts, although these are not really
distinct: — 1, an outer, brown, soft layer,
which supports the ciliary nerves and long
ciliary vessels, and contains anteriorly the
ciliary ligament — the outer pigment layer ;
2, a less highly coloured proper vascular
layer, with the larger arteries and veins ;
and 3, a colourless delicate inner layer,
containing an extremely copious capillary
network — the choro-capillary membrane,
which does not extend anteriorly beyond
the margin of the retina. The stroma of
the choroid proper consists of very irregular
spindle-shaped or stellate cells, from 1-1500
to 1-COOO" in length, either paler, or con-

EYE.

[ 311 ]

EYE.

Fig. 208.

taming a large quantity of pigment, and
anastomosing by numerous long and very
slender processes (fig. 208). These cells are
most distinct in the
outer layer ; whilst
more internally, and
especially in the cho-
ro - capillary mem-
brane, they gradually
pass into a homoge-
neous or slightly stri-
ated nucleated tissue,
containing but little
and ultimately no
pigment.

In some animals
the choroid mem-
brane contains mus-
cular fibres. Cells from the stroma of

Between the stro the choroid;«' containing
-*' pigment; b, fusiform cells

ma and the pigmen- without pigment; c, ana-
turn nigrum is a very 8t°niosi8 of the former.
, , . °, , . , J Magn. 3oO diams.

thin elastic layer ;

this is either structureless, granular, or finely
reticulated, and is comparable to a base-
ment membrane.

The ciliary muscle — tensor choroidees (fig.
207 &) — is composed of a tolerably thick
layer of radiating unstriated muscular
fibres; these, intermixed with pigment-
cells of the choroid, pass from the anterior
margin of the sclerotica to the ciliary body,
and lose themselves in its anterior half,
opposite the base of the ciliary processes.
The fibre-cells are 1-600" in length, broader
than most fibre- cells, and not easily isolated
in man.

The ciliary processes consist of the same
stroma as the choroid; but the stellate
cells are more delicate and fewer, and, with
the exception of those at their base, do not
contain pigment; nor are they furnished
with the elastic lamina.

The piymentum nigrum (fig. 207 in) lines
the inner surface of the choroid, and as far

Fig. 209.

Cells of the human pigmentnm nigrum a, surface
dew ; b, side view ; c, pigment-granules.

Magnified 350 diameters.

as the termination of the retina, consists of
a single layer of beautiful, regularly six-
sided cells (fig. 209 a, b), from 1-2000 to
1-1500" in diameter ; they contain abund-
ance of pigment. Beyond the margin of
the retina, the cells f orm mostly two layers,
and become rounded and more loaded with
pigment. The granules of pigment are
very minute, rounded, from 1-20,000 to
1-30,000" in diameter, and exhibit mole-
cular motion. In the eyes of albinos, and
in the region of the tapetum of animals, the
cells contain no pigment.

The iris (fig. 207, I) consists of three
layers : — an anterior epithelial layer ; a pos-
terior layer of pigment, called the uvea, and
continued from the inner pigment layer of
the choroid ; and a middle, the thickest or
fibrous layer.

The fibrous layer differs from the choroid,
in containing connective tissue forming deli-
cate loose bundles, some of which pursue a
radiating, others a circular course, and in-
terlacing variously; in this tissue are a
number of spindle-shaped or stellate cells,
containing pigment, corresponding to those
of the choroid, and in addition to nume-
rous blood-vessels and nerves, two sets of
muscular fibres : the latter in some animals
are transversely striated ; but in man they
resemble the ordinary unstriped fibre-cells,
and are 1-600 to 1-400" in length. One set
forms a sphincter for closing the pupil, its
fibres taking a circular direction ; the other
set consists of bundles of radiating fibre-
cells, traversing the stroma of the iris. The
pigment layer or uvea consists of the same
elements as those of the corresponding laver

A . i t • i *• D v

of the choroid.

The anterior coat consists of a single layer
of rounded, flattened epithelial cells.

The blood-vessels of the choroid mem-
brane and ciliary processes are easily injected
(e. g. in the sheep or ox) from the ciliary
arteries, and form a magnificent object.

The retina is the terminal membranous
expansion of the optic nerve within the
globe of the eye. It consists of nerve-cells
and fibres, imbedded in a spongy supporting
connective tissue.

Nine layers are distinguishable in a
transverse section of the retina (fig. 210),
commencing from within: viz. 1, the inter-
nal limiting membrane (b) • 2, the layer of
optic nerve-fibres (d) • 3, a layer of nerve-
or ganglion-cells (e) ; 4, a molecular layer j
5, an inner granular layer (/) ; 6, an inter-
mediate granular layer (g) • 7, an outer

EYE.

C 312 ]

EYE.

granular layer (h) ; 8, a narrow outer limit-
ing membrane ; and 9, the layer of cones
(*'), and bacilli (k). The pigment-cells
of the choroid membrane are also some-
times considered a layer of the retina.

Fig. 210.

Perpendicular section of a piece of the posterior part
of the human retina.

a, hyaloid membrane with nuclei ; 6, internal limiting
membrane ; c, ends of the radiating fibres, so altered
aa to present a cellular appearance; d, layer of
optic nerve-fibres; e, layer 01 nerve-cells; f, inner
granular layer: g, intermediate or finely granular
layer, in which the radiating fibres are more distinct
than elsewhere; h, outer granular layer; t, inner
division of the layer of bacilli, with the cones ; k, outer
division, with the processes of the cones and the true
bacilli.

Magnified 350 diameters.

The internal limiting membrane (b) is an
extremely delicate structureless film, cover-
ing the inner surface of the retina, including
the entrance of the optic nerve, and the
macula lutea.

The expansion of the optic nerve forms
a membranous layer of extremely delicate
transversely radiating fibrils (fig. 211,5),
from 1-24,000 to 1-12,000" in diameter,
and mostly exhibiting varicosities. They
contain no nuclei, and appear to consist of
the axial fibres only. They are aggregated
into 'flattened bundles which either run
parallel or anastomose with each other.
They are absent, or at least as a coherent
layer, opposite the macula lutea.

The layer of nerve-cells (e) consists of
ordinary nerve-cells, pyriform, roundish, or
angular, with pale processes ; they vary in
diameter from 1-3000 to 1-750".

The molecular layer lies between the
ganglion-cell layer (e) and the inner granular
layer (/). The outer limiting membrane
is situated between the outer granular
layer (h) and the layer of cones and bacilli
0>

The remainder of the retina is mainly
composed of a very large number of parallel,
very slender (1-60,000 to 1-20,000" diame-
ter), highlv refractive, radiating fibres or
tubes (Muller's fibres), with their axes at
right angles to the surface of the choroid,
upon which their outer ends rest, whilst
their inner, triangular or branched ex-
tremities are in contact with the limiting
membrane. They produce the striated
appearance presented by a section of the
retina (fig. 210). They are furnished at
certain parts of their course with expan-
sions containing each a nucleus j and the
fibres are very numerous. These nucleated
expansions being opposite each other, or in
the same planes, give rise to the appearance
of distinct granular layers mentioned above.
The more internal nucleated expansions are

Fig. 211.

Elements of the human retina. 1. "Radial fibres with
bacilli : k, bacillus, connected with the fibre (r) by its
inner acute end ; h, nucleated expansion (cell), appear-
ing in the outer granular layer ; I, expanded end of the
fibre, resting upon the limiting membrane m; k1, a
bacillus connected with a cone i ; r', fibre running from
the cone to the cell./ of the inner granular layer ; »,
branched termination of a radial fibre, often present.
2. Bacilli separated from the fibres, broken and curved,
&c. 3. Fibrils from the expansion of the human optic
nerve : a a, larger, b, smaller, fibrils with varicosities ;
c, undulating pale fibres belonging probably to the pro-
per radiating system. 4. Two cones connected with
bacilli, and fragments of the fibres remaining : a, ba-
cillus ; b, cone ; c, nucleus of cone.

Magnified 350 diameters.

EYE.

[ 313 ]

EYE.

connected with the nerve-cells of the retina
by minute nerve-tubes.

Their outer portions have been distin-
guished as the bacilli and cones; but the
whole probably form one continuous system
of nerve-cells and tubes.

The bacilli, regarded (fig. 211, 1 k k', 2} as
distinct bodies, are cylindrical, narrow and
elongated, of the same breadth through-
out, truncated externally, and terminating
internally in a more slender portion of the
fibre; they are from 1-430 to 1-330" in
length and 1-1 5,000" in breadth ; near the
point of attachment to the fibre is a trans-
verse line. They are extremely delicate,
and easily broken or deformed. The cones
(tig. 211 1 i, 4 ty are bacilli with a conical
or pyriform body, and are also very easily
injured. A slight constriction divides each
cone into two parts, the innermost of which
(fig. 211 4 c) contains a nucleus. The cones
are from 1-6000 to 1-4000" in diameter.
In most parts of the retina the cones are
surrounded by several bacilli ; opposite the
macula lutea they alone form a continuous
layer ; whilst at its margins, single bacilli
intervene between the cones (fig. 212).

Fig. 212.

End view of the rows of bacilli and cones from the
outside. 1, opposite the macula lutea, cones only ;
2, at its margins ; 3, at the middle of the retina, a,
cones or spaces corresponding to them ; 6, bacilli of the
cones, th« ends of which are often situated somewhat
beneath the level of those of the true bacilli, c.

Magnified 350 diameters.

Opposite the entrance of the optic nerve,
both bacilli and cones are absent. These
curious bodies are more distinctly seen in
many animals than in man (PL 50. fig. 5),
and they present certain varieties: thus,
the cones are deficient in bats, the hedge-
hog, the mouse, the mole, and the sharks
and rays ; while the bacilli are deficient in
the reptiles.

The inner ends of the radiating fibres
when overlapping each other, and especially
when swollen by the action of water,
present the appearance of a number of

rounded or angular cells (fig. 210, c), for
which they were once mistaken.

It is thus evident that, excepting the
layer of nerve-cells and that of the fibres of
the optic nerves, the retina cannot truly be
considered as composed of layers. The
series of bacilli and cones, when torn from
their connexion with the radial fibres, form
the so-called Jacob's membrane.

Between the nerve-fibres, from the outer
to the inner limiting membrane, lies the
connective supporting tissue ; this also
forms a considerable portion of the mole-
cular and granular layers. In modern
works, the fibres of this tissue are called
M tiller's fibres. But Kolliker has shown
that the true radiating or Muller's fibres
are not dissolved by boiling, and are coloured
red by Schultze's test; so that they have
not the chemical composition of connective
tissue.

We cannot enter into the physiology of
these radial fibres, which have been shown
to be the percipients of light.

Crystalline lens. The crystalline lens is
contained in a capsule (fig. 207 q s), con-
sisting of a perfectly structureless, very
elastic membrane, the anterior half of
which is lined with a single layer of very

Fig. 213.

Fibres or tubes of the lens of the ox.
Magnified 350 diameters.

EYE.

[ 314 ]

EYE.

transparent, polygonal, epithelial cells (fig.
207, «), from 1-2000 to 1-1200" in diameter.
The lens itself consists of long, transpa-
rent, six-sided, flattened fibres (fig. 213),
from 1-4800 to 1-2400" in breadth and
1-8500 to 1-13,000" in thickness ; these are
tubular, at least in the outer portions of the
lens, and contain a tenacious sarcodic sub-
stance, which escapes from the ends of the
broken fibres in irregular globules. The
form of the fibres is best seen in a transverse
section (fig. 214).

Fig. 214.

Transverse section of the fibres or tubes of the hu-
man lens.

Magnified 350 diameters.

The fibres are firmer, narrower, and more
highly refractive towards the centre of the
lens. Their general arrangement is such
that their broad surfaces are parallel with
the surface of the lens, and that they fol-
low a direction from the middle of the
anterior to that of the posterior surface,
curving laterally in their course — not, how-
ever, exactly from the middle, but from
the arms of a star-shaped kind of centre,
at which parts (fig. 215) the fibres are

Fig. 215.

Anterior view of human crystalline lens (adult),
showing the stars and the direction of the fibres.
Magnified 5 diameters.

replaced by a homogeneous or finely gra-
nular matter. The arms of the star present
upon the surfaces are the extremities of
planes extending through the substance of
the lens, from which the inner fibres take
their origin. The arms of the anterior and
posterior stars are not parallel with each
other j nor are the fibres arising from any
part of the arm of one cross inserted into
the corresponding part of the arm of the
opposite cross. Great variety exists in dif-
ferent animals in the structure and arrange-
ment of these stars and planes. Thus in
the human foetus the star has three arms or
planes, whilst in the adult there are from
nine to sixteen, of which three are frequently
more distinct than the others. In some
animals they are replaced by a pole, from
which the fibres radiate like meridians, as
in the cod, the Triton, and Salamandra ; in
others, there is a single plane, as in some
fishes, the frog, the hare, the rabbit, and the
dolphin ; whilst in most of the mammalia
there are three, and in the whale, the bear
and the elephant there are four.

The edges and marginal surfaces of the
fibres of the lens are uneven or toothed, so
that their lateral connexion becomes more
intimate ; hence the lens separates more
readily into parallel laminae in the direc-
tion of the surface than in the opposite
direction.

In many animals, especially fishes, as the
cod, the roach, &c., the irregularities of the
fibres of the lens are replaced by beautiful
teeth (PI. 50. fig. 6).

Vitreous humour, or body, is enclosed in
a membrane, the hyaloid membrane, which
behind the dentate margin of the retina is
extremely thin and delicate ; anterior to this
it becomes firmer (fig. 207 t) and passes,
forming the zonule of Zinn, to fuse with the
capsule of the lens. In thus doing, it sepa-
rates into two layers: — a posterior (v\
which becomes consolidated with the cap-
sule of the lens somewhat behind its mar-
gin ; and an anterior (u), connected with the
ciliary processes, which becomes attached
to the capsule of the lens, a little in front
of its circumference : between these two is
the canal of Petit (C.P.). The posterior
layer is sometimes considered as arising
from a condensation of the tissue of the
vitreous humour. The structure of the
vitreous body is still obscure.

The structure of the eye is very difficult
of examination, the parts being so delicate
and easily injured. Many of them can be

EYE.

[ 315 J

FASOLE.

made out by dissecting the eye under water ;
but the more delicate structures should be
immersed in the liquid of the anterior
chamber. Solution of chromic acid and
alcohol is useful for hardening the parts to
allow of sections being made with a Valen-
tin's knife. The cornea may be hardened
in chromic acid, sections cut in paraffine,
and stained with logwood. The nerves and
corpuscles are best stained with nitrate of
silver or chloride of gold. The retina may
be hardened in chromic acid and spirit,
and the rods and cones in osmic acid,
sections being made by freezing ; logwood
stains the granular layers, the rods and
cones remaining unaltered. The lens should
be hardened, either by maceration in solu-
tion of chromic acid, or by drying. The
fibres may be well preserved in the dry
state.

The structure of the eyes of the lower
animals is briefly noticed under the classes,
&c. In the mammalia generally, it is
essentially the same as in man j and the eye
of the ox or sheep may be selected for
examination.

BIBL. Kolliker, Mik. An. ; Todd and
Bowman's Phys. of Man] Miiller, H.,
Comptes Rendus, 1856, 743 (Ann, N. H.
1856, xviii. 492) ; Nunneley, Qu. Micr.
Jn. 1858, 136 ; Schultze, An. und Phys. d.
Retina (8 pi.), 1867, & Strieker's Handbuch,
976; Hulke, Mn. Mic. Jn. ii. 227, Phil. Tr.
cv. 109; Lawson, Ciliary Muscle of Birds,
ibid. ii. 204 ; Frey, HistoL, 1876, and the
full literature therein ; Klein, HistoL 342 ;
Hannover, Ret. de Fhomme et d. Vertebr.,
1877; Gerlach, An. mensch. Auge,I88Q;
Eloni, Cornee d. an. vert. 1881.

EYLAIS, Latr. — A genus of Arachnida,
of the order Acarina, and family Hy-
drachnea.

Char. Palpi longish, fourth joint longest,
the fifth obtuse, somewhat tumid, spinous ;
mandibles unguiculate ; rostrum very short,
mouth round; body depressed; two ap-
proximate pairs of eyes ; coxae compara-
tively narrow, the fourth only in contact
with the third at its base.

E. extenders (PI. 6. fig. 28). Skin soft,
furrowed, with the ramified alimentary canal
visible through its substance. Between the
two anterior coxae (d) is seen the bilobed
labium (a), the posterior portion containing
the round and ciliated mouth, the anterior
portion forming a kind of hood ; palpi (6)
with the three first joints very short; man-
dible consisting of a long thick joint, with

a thick mobile claw (c). Fig. 28 d, under
surface of body, exhibiting from before
backwards : — the mouth, with the hood, and
the palpi ; next two groups of anterior coxae ;
the vulva and two stigmata ; the four pos-
terior coxae ; and, lastly, the anus in the
middle, with a stigma on each side.

The larvae are hexapod, reddish, pellucid,
with the eyes four, wide apart.

E. confinis, K.

E. atomaria, K.

BIBL. Duges, Ann. Sc. Nat. 2 se"r. i. 156 ;
Gervais, Walcken. Arachnid, iii. 207 ; Koch,
Deutschl. Crustac.

F.

FABULARIA, Defrance.— A porcella-
neous Foraminifer, growing like a Bilocu-
lina, but having its chambers filled with
labyrinthic shell-matter, the cavities in
which are mostly elongate with the axis
of the shell. They are narrow, and, open
ing terminally, make a cribriform septal
face.

Quinqueloculina saxorum has thickenings
within, making internal grooves and ridges,
thus verging on the Fabularian type ; and
Hauerina has a cribriform septal plate, but
without superadded internal structure.

Fabidaria ovata (De Roissy), known also
as F. discolithus of Defrance, abundant in
the Eocene Tertiaries of France, is the only
known species.

BIBL. Carpenter, Introd. For am. 82.

FADYE'NIA, Hook.— A genus of As-
pidieae (Polypodiaceous Ferns); 1 spec.,
Brazil.

FyECES.— We shall not dwell upon the
nature of the objects contained in the faeces ;
suffice it to say that they may consist of :
— the elements of the various secretions
poured into the intestinal canal ; the pro-
ducts of inflammation ; undigested remains
of articles of food, or bodies taken with the
food or drink ; and entozoa (Anchylostoma,
Anguttlula,Trichocephalus),Amo2bce,Bacteria
&c. Some of these resemble other bodies
very closely to the naked eye. The use of
chemical reagents should never be omitted
in their examination.

FARREL'LA, Ehr.— A genus of Cteno-
stomatous Polyzoa, fana. Vesiculariidae.

F. repens ; no gizzard ; on shells, algae &c.
(Hincks, Polyzoa, 528.)

FASCLE.— The fascias consist of the
same elements as AREOLAR TISSUE, and

FATTY DEGENERATION. [ 316 ]

FEATHERS.

present all the varieties of arrangement in-
termediate between it and TENDON.

FATTY DEGENERATION. See DE-
GENERATION, FATTY.

FATTY TISSUE, or ADIPOSE TISSUE.
— This is formed of colourless cells, with a
very delicate, transparent/structureless cell-
wall, enclosing, in the normal state, glo-
bules of yellowish fat (PL 49. fig, 41). The
cells generally occur in groups, surrounded
by or imbedded in connective tissue. They
are rounded when isolated, or polygonal
when aggregated, and from 1-800 to 1-300"
in diameter; and the fat so fills them,
that neither the nucleus which they contain
nor the cell-wall is visible. The fat may
be removed by drying them, and digesting
with ether, when the cells appear contract-
ed and wrinkled. In emaciated and drop-
sical subjects, each cell contains a number
of small globules of fat, frequently of a
reddish colour (PI. 38. fig. 3), together with
serum, and the nucleus is very distinct.
Sometimes in these cases the cells are some-
what spindle-shaped or stellate. The fat con-
tained in the cells is ordinarily in a liquid
state ; but sometimes the margarine separates
in the crystalline form (PL 11. fig. 15 a).

In the mammalia generally the fatty
tissue occurs in the same localities, and has
the same structure, as in man. In fishes,
the fatty matter is deposited principally in
the liver. In reptiles, it occurs chiefly in
the abdomen : thus in the frog and toad it
forms long appendages occupying the sides
of the spine. In birds, it exists chiefly be-
tween the peritoneum and the abdominal
muscles, and in some of the bones. In many
of the lower animals it appears to exist in
the state of solution only.

Fatty tissue is formed from connective'
tissue cells.

Fatty matter may be deposited in cells
of all kinds, as in FATTY DEGENERATION.
During the development of cells, it exists in
solution. The action of solution of potash
is often of service in distinguishing globules
of protoplasm, which have a high refrac-
tive power, and much resemble those of
fat, from this substance, as it dissolves the
former, but not the latter ; solution of osmic
acid renders fat-globules black.

BIBL. Todd and Bowman, Phys. of Man ;
Kolliker, Mikr. An. ; Klein, Hist. 42 ; Frey,
Hist.

FAUJASINA, D'Orb.— A delicate and
handsome Foraminifer, but not typical.
F. carinata, D'Orb., found in the Maas-

tricht Chalk, is a thin asymmetrical (plano-
convex) Polystomella, somewhat thinner or
flatter than P. macella (F. & M.), which is
a subcomplanate, perhaps starved, variety
of P. crispa (Linn.).

BIBL. Parker and Jones, Ann. N. H.Sser.
v. 104 ; Carpenter, Introd. 213, 286.

FAVEL'LA.— A form of the concepta-
cular fruit of the Florideous Algae, where
the spores are collected in spherical masses
situated wholly upon the external surface of
the frond, as in Ceramium&nd Callithamnion.
FAVELLIDTUM.— A form of the con-
ceptacular fruit of the Florideous Alga?,
where the spores are collected in spherical
masses attached to the wall of the frond or
imbedded in its substance, as in Halymenia
and Dumontia. The term is usually ex-
tended to similar fruits not perfectly im-
mersed, e. g. those of Gigartina, Gelidium,
&c., where they form tubercles upon the
branches. Sometimes these tubercles open
by a pore on the surface, when mature, to
emit the spores.

FA'VUS (Porrigo in part, Willan and
Bateman). — A disease of the skin, character-
ized by the presence of cup-shaped isolated
or aggregated crusts, consisting of a Fungus.
(See ACHORION.)

FEATHERS OF BIRDS.— Feathers agree
in all essential points of structure with the
hairs of other animals.

Each feather is composed of a quill (con-
taining the pith), a shaft, and a vane or
beard with its barbs. The whole consists
of a number of epidermic cells, often con-
taining pigment, but in most parts so con-
solidated or fused together as to be imper-
ceptible.

In the quill, the cells are flattened, elon-
gated, and arranged with their long axis in
the direction of that of the feather, and
their nuclei have the same form as those
of the corresponding part (cortex) of the
human hair. The cells of the pith are often
undistinguishable in old feathers, whilst in
the younger ones they are very distinct,
rounded or polygonal, and contain air. The
shaft and the barbs exhibit the same cortical
and medullary structure ; the latter is often
beautifully distinct (PL 22. figs. 14 & 15 c),
and causes them to resemble closely the
hairs of some Rodents. The barbs are some-
times furnished with secondary barbs, or
barbules, resembling them in form, but dif-
fering mostly in the absence of the pith.

Feathers are developed in a capsule, and
from a pulp or matrix, as in the case of

FEET.

[ 317 ]

FERMENTATION.

hairs. Hence a feather may be regarded
simply as a large, doubly or triply pinnate
hair.

During development, the cell structure is
very distinct ; but in the mature feathers,
digestion with solution of caustic potash is
requisite to render this visible ; and fre-
quently even under these circumstances, the
nuclei alone can be detected.

The barbs of some feathers resemble the
shafts, being rounded or angular, and free
or unattached (figs. 17 & 18) ; but in others
they are flattened, and linked together in a
remarkable manner, much resembling that
met with in the wings of Hymenopterous
and other Insects (PL 34. figs. 11 & 13), and
which has been so often adduced as one of
the many wonderful instances of design in
the creation. Thus the upper or outer
margin of each barb is fringed on both sides
with hair-like elongated processes or pinnae
(PI. 22. fig. 15 «, 6), which differ in struc-
ture on the two sides. On one, and this
always the same side of each barb (fig. loft),
the pinnae are toothed on one edge (fig. 16 b* ),
whilst the pinnae arising from the other side
(fig. 15 c) exhibit, beyond the middle, a
number of curved hooks (fig. 16 a), which
clasp around the first kind existing upon
the adjacent barb, so as to retain a firm hold
upon them, this being aided by the teeth,
which prevent them from slipping. If the
relative position of the two sets of pinnae
which spring from two adjacent barbs be
examined, it will be seen that they cross
each other at a considerable angle, so that
any pinna from one barb crosses several of
those belonging to the next barb. Hence
each pinna is connected by its hooks with
several of those which it crosses ; for the
pinnae with hooks are situated outside or
above those not furnished with these ap-
pendages. The under or inner margin of
each barb is simply membranous, and curved
so as to overlap that of the next.

The free barbs of feathers are often met
with in the examination of liquids &c. left
exposed to the air (figs. 17 & 18).

BIBL. Schwann, Mik. Untersuch. ; Re-
clam, De Plamar. Evolut. ; Leydig. Histol.
99 ; R. Beck, Achr. Micr. 31.

FEET.— In descriptions, &c., of the Arti-
culata, especially of Insects, the word feet
is mostly used to designate the legs j hence
when met with in the wrorks of systematic
and other writers on these classes, it must
be understood to mean the legs.

FEET OF INSECTS. See INSECTS, Legs.

FEGATEL'LA, Raddi (Conocephalus,
Hill). — A genus of Marchantiaceous Hepa-
ticae. F. conica (Marchantia cornea, Brit.
FL), the only British species, is not un-
common, and is one of the largest of the
tribe. It is distinguished from Marchantia
by its nearly entire conical fertile receptacle.
The dichotomously divided frond is of a
yellowish green colour. This genus is re-
markable for the mode in which the pedicel
of the sporange becomes detached from the
base of the epigone before the former bursts
(fig. 220) ; the perigone holds the sporange
firmly between its valves until empty, and
then lets it fall out, together with its pe-
dicel. Hence fully-developed sporanges
are seldom found in dried specimens. (See
MABCHANTIE^;.)

Fig. 219.

Fig. 220.

Fegatella conica.

Fig. 219. Vertical section of the upper part of a fer-
tile receptacle, showing four of the sporanges sur-
rounded by their perigones and epigones almost en-
closed in the conical receptacle. Magnified 10 diams.

Fig. 220. A sporange just before bursting, enclosed in
its epigone ; its pedicel detached at the base. Magn.
20 diams.

BIBL. Hooker, Brit. FL v. pt. 1. 107 ; Bis-
choff, Nova Acta, xvii. 970, pi. 68; Engl.
Bot. pi. 504.

FEL'SPAR. See ROCKS.

FEL'STONE. See ROCKS.

FENESTRELLA, Grev.— A genus of
Diatornaceae.

Char. Frustules free, disciform ; disk with
minute radiant dots, interrupted in the
middle by a transverse band, composed of
parallel lines of dots, band terminated at
each end by a flat ocellus (nodule).

F. barbadensis. Barbadoes deposit.

BIBL. Greville, Micr. Tr. 1863, p. 67.

FERMENTATION.— Under this name
are understood various processes of decom-
position of organic compounds; although
it would be desirable to restrict it to those
taking place with the cooperation of living
organisms. The most familiar examples of
the fermentation produced by the growth

FERMENTATION.

C 318 ]

FERMENTATION.

of living organisms, are those which convert
saccharine infusions into spirit, vegetable
juices into beer, wine, &c., or vinegar j and
occur generally in watery solutions of vege-
table substances containing saccharine mat-
ters or other ternary compounds with a
certain amount of nitrogen ; with these is
included also the putrefactive fermentation
of moist animal or other highly nitrogenous
substances.

Much obscurity still prevails upon this
subject; but all investigations appear to
tend in the direction of proving that these
changes are absolutely dependent upon the
agency of Fungi; and that each kind
of fermentation is produced by a distinct
vegetable organism. Thus: the vinous fer-
mentation appears to depend entirely upon
the growth of Yeast, a microscopic fungus,
in the liquid (see YEAST) ; while milk-fer-
inentation is caused by Bacterium lineola ;
butyric fermentation by Bacillus suUilis &c.
Yet, according to the experiments of Muntz
and Pasteur, it appears that the living cells
of the higher plants, can in the absence of
oxygen, act like fungi, and produce a true
introcellular alcoholic fermentation. The
Yeast-plant as ordinarily known, appears
so associated with Penicillium, that there
seems no doubt as to the necessary relation
between them. We find that beer, exposed
to the air at ordinary summer temperatures,
soon becomes coated with the minuter glo-
bules (conidia) of Yeast, forming a dry-
looking whitish powder over the surface ;
and very soon after, Penicillium glaucum
makes its appearance in fruit. Turpin found
the same thing in milk. Again, the ' vine-
gar-plant,' as it is called, which converts
solutions of sugar into vinegar, seems to be
undoubtedly the mycelium of Penicillium
glaucum, as it fructifies with the characters
of this when the liquid is exhausted ; but
the gelatinous mass of mycelium contains,
intermixed with the ordinary filaments of
this genus, spherical and elliptical cells and
chains of cells of all sizes, many of which
are undistinguishable from the Yeast- plant,
and the mycelium of Oidium. It must be
recollected also, that the growth of true
Yeast is favoured by a certain amount of
heat, while the Penicittium-ja.jceHu.in. grows
luxuriantly at ordinary temperatures. Dead
Yeast causes no fermentation.

The f mother ' of vinegar, which finally
decomposes the acid, appears to be the same
plant ; and no satisfactory distinction can
be drawn between this and those mycelia

forming cloudy flocks in and decomposing
various saline solutions, &c., described as
species of Hygrocrocis, Leptomitus, &c. The
decay of wood, again, is often greatly ac-
celerated by the growth of the mycelium
of Fungi, which seems to decompose the
organic compounds in the wood in the same
way that the Yeast does those in organic
liquids. A general law indeed appears to
prevail throughout the Fungi, that their
nutrition differs from that of all other plants
in depending exclusively on the absorption
and decomposition (with the evolution of
carbonic acid) of organic compounds, there-
fore consisting of the performance of the
operation of fermentation on the organic
matters upon which they feed. Details upon
the microscopic phenomena attending fer-
mentation produced by Fungi will be found
under YEAST, VINEGAR-PLANT, TORULA,
PENICILLIUM, and SCHIZOMYCETES.

The fermentation of animal substances,
and of vegetable substances containing
abundance of nitrogen, in which ammonia
is liberated, is generally called putrefaction,
or the putrefactive fermentation. This pro-
cess has been shown to be produced by the
growth of living organisms resembling those
causing the fermentations alluded to in the
foregoing paragraphs ; and when the organic
liquids are thoroughly boiled and sterilized,
they may be kept indefinitely without
change. "These organisms appear in myriads
during the decomposition which takes place
when a piece of meat, &c., slices of potato,
fleshy Fungi, &c., are kept moist and ex-
posea to the air for some days in warm
weather; and they continue to multiply
until the putrefaction is complete, when
they die away. It is a question perhaps
whether they liberate the ammonia and
carbonic acid by a kind of respiration while
living, or as an excrement.

One point of interest connected with the
fermentation -plants must not be passed
over, viz. that the supposed distinction be-
tween the chemical processes of nutrition
in animals and plants, falls to the ground
when these Fungi are taken into considera-
tion ; as they do not live by converting in-
organic substances into organic compounds,
but, like animals, decompose ready-formed
organic compoumds into others and into
their inorganic elements.

BIBL. Turpin, Mem. Museum, 1840 ; Bail,
Flora, 1857, 417 ; Mulder, Chem. of Veg.
and An. Phys. ; Liebig, Lett. Chemistry,
1231; Gmelin, Organ. Chem.; Lowig, C'hem.

FERNS.

[ 319 ]

FERNS.

org. Verb. i. 223 ; Mitscherlich, Pogg. An-
na/. Iv. 224 ; Lekrb. 4. ed. 371 : Cagniard
Latour, Pogg. Ann. xli. 193; Schwann,
ibid. 184 ; Uie,Eiblioth. Genev. 1839 ; Helm-
holtz, Miiller's Archiv, 1843, 453 ; Reess,
Alcoholgdhrungs - Pilze, 1870 ; Pasteur,
Etudes s. 1. Vmaigre, 1868, *. I Tin, 1872,
*. /. £iere, 1876 ; V. Tieghem, Ann. Sc. Nat.
yiii. 1868; Fremy, Gener. d. Ferments, 1875;
Schutzenberger, Ferment. 1875; Gayon,
Ann. Sc. Nat. 1875, i. 5 ; Muntz, Ferment,
Compt. Rend. 1878 (Jn. Mic. Soc. 1878,
23) ; Lister, Qu. Mic. Jn. 1878, xviii. 177 ;
Nageli, Theor. d. Gahrung, 1879 ; Sachs,
JBot. 254 ; Tyndall, Putrefaction $c. 1881.
See also TORTJLA and PENICILLIUM.

FERNS.— This class of Flowerless Plants
offers very many points of interest to the
microscopist ; and indeed the use of magni-
fying-instruments is indispensable in their
examination for botanical purposes. The

Fig. 221.

Scolopendrium vulgare ; underside of frond.
Nat. size.

Ferns are characterized by the position of
their spore-cases or fruits (thecae, sporangia,
or capsules), which are collected into what

to the naked eye look like spots, streaks,
or patches of a brown colour (son) at the
back or lower surface of the leaves or fronds
(fig. 221), or at their margins, — these fer-
tile leaves either resembling the rest, or
being modified in a manner which more or
less disguises their nature, as in what are
miscalled ' flowering Ferns' (Osmunda (figs.
222 & 223), Botrychium, &c.).

The Ferns possess a stem which is more
or less developed in different cases : in our
native kinds it is either a slender, horizon-
tal, subterraneous rhizome or rootstock, or
a thick, short, erect one rising little above
the ground ; but in foreign kinds this erect

Fig. 222.

Fig. 223.

Osmunda regalis.

Fig. 222. Upper part of a frond, l-6th nat. size.
Fig. 223. A fertile pinnule bearing thecse without
parenchyma. Magnified 10 diams.

stem attains the forms and dimensions of a
tree, growing up into a tall unbranched co-
lumnar stem, sometimes more than fifty feet
high. The anatomical structure of the
stem of the Ferns is peculiar and special,
depending on the character and arrange-
ment of the fibro- vascular bundles (see
TISSUES, VEGETABLE), which afford the
best examples of that form of elementary
tissue called the SCALARIFORM DUCTS. The
creeping rhizomes are often clothed more
or less thickly (as are also the leaf- stalks)
with brown membranous scales called RA-
MENTA ; and these often afford elegant mi-
croscopic objects, from the peculiar arrange-
ments of the cells. The leaves are gene-
rally very greatly developed ; and the green
blade is of more or less complex structure
in different genera. In the Hymenophylla,

FERNS.

[ 320 ]

FERNS.

Filmy Ferns, the leaf is ordinarily a mere
membrane of a single layer of cells, through
which ramify scalarifrom ducts, to form the
veins — consequently there are no stomata ;
but in the other orders, in Pteris for ex-
ample, the leaf has an upper and lower epi-
dermis with stomata, with loose cellular
tissue (mesophyllum), between and through
which ramify the fibro- vascular veins : the
epidermal cells often have elegantly zig-
zagged or waving side-walls, which pro-
duce a pleasing appearance in the sections
of the structure obtained in slices shaved off
horizontally from the surface of the leaf.

The mode of ramification of the veins or
nerves of the leaves is important in system-
atic Filicology, and may be observed for
such purposes by immersing the dried leaf-
lets in turpentine or oil, or mounting them
in Canada balsam. The collections of spo-
rangia or capsules on the back of the leaves
sometimes occur on all of these ; in other

Fig. 224.

Nephrodium.

Pinnule with indusiate sori.
Magnified 10 diameters.

there are barren leaves and fertile
leaves, the latter of which are generally
somewhat modified in form, deprived of a
certain portion of the green expanded struc-

ture, and reduced occasionally to a mere
ramification of veins or ribs supporting the
sporangia (fig. 223).

The groups of sporangia are called sori ;
they differ much in form and arrangement,
and are either naked (Polypodium) , or co-
vered by a special membranous structure,
more or less continuous with the epidermis
of the lower surface of the leaf, called an in-
dusium or involucre (fig. 224) ; sometimes
this indusium is so constructed as to form a
kind of cup (figs. 127 & 151), which, again,
exhibits a great variety of modifications.
(See SORI and INDUSIUM.)

The theccB or sporangia are usually col-
lected in great numbers in the sori ; and con-
sist of minute stalked sacs or cases, com-
posed of simple cellular membrane, the cells
of which are either all alike (OPHIOGLOS-
SUM), or a row of them running almost
round the sac are modified by the thick-
ening of their walls, so as to form an elastic
band (annulus), which causes the bursting
of the sac when ripe. In the Polypodiaceae
the annulus starts from the stalk of the
capsule (fig. 225) j in Hymenophyttum and

Fig. 225.

Polypodiuin verrutosum.
Stalked thecae with annuli. Magnified 25 diameters.

Fig. 226. Fig. 227.

Ceratopteris thalictroides.
Fig. 226. Theca. Magn. 50 diarns.
Fig. 227. Do. bursting. Do.

FERNS.

[ 321 J

FERNS.

Trichomanes it runs round in an oblique line
(like the ecliptic line on a globe) ; in Glei-
chenia it is also oblique (fig. 231) ; and in
Schizcea and Aneimia (fig. 12, p. 41) &c.
it forms a kind of cap on the summit of the
case.

Fig. 228. Fig. 229. Fig. 230.

Ceratopteris thalictroides.
Figs. 228-230. Spores. Magn. 150 diams.

Fig. 231.

Grleichenia.-
A theca. Magnified 40 diams.

^ membranous sporangia are filled

with spores having a double coat, like pol-
len-grains ; and, as in these, the outer coat
is ordinarily coloured, and either smoothish
or marked with points, streaks, ridges, or
reticulations (figs. 228-230, 232-235). (See
SPOKES.)

Fig. 232.

Fig. 233.

Fig. 234.

Fig. 235.

Spores of Ferns.

Fig. 232. Aneimia asplenifolia.
Fig. 233. Polypodium aureum.
Fig. 234. Cystopteris fragilis.
Fig. 235. Pteris longifolia.

Magnified 100 diameters.

The reproduction of the Ferns by their
spores exhibits some very remarkable phe-
nomena. When the spores are sown, they
germinate after a time by a protrusion of
the inner coat as a delicate membranous
pouch (fig. 236), which elongates and be-
comes divided by septa into an articulated
cellular filament ; some of the cells emit
slender tubular, not septate, filaments, form-
ing radical hairs; and while these remain
imcoloured, the larger cells from which they

Fig. 236.

Fig. 237.

Fig. 238.

Fig. 239.

Germination of Pteris longifolia. Magn. 100 diams.

arise acquire chlorophyll-granules. The
young prothallium, as it is called, increases
in size by cell-division, and at length ac-
quires somewhat the form of a heart (figs.
236-239). Some of its cells produce, upon the
margin or the under surface, the trichonia-
tous structure! called antheridia ; which con-
sist of stalked cellular bodies, of simple but
peculiar structure, in the interior of which
are developed minute cellules containing
ciliated spiral filaments, the spermatozoids.
These are corkscrew-shaped, with 3 or 4

coils, and the front end finely ciliated.
On the bursting of the antheridial sac,
they escape, not only from this, but from
their own parent-cells, and swim about
actively in the water by the aid of their
vibratile cilia (PI. 40. fig. 34).

The antheridia are often formed in large
numbers, and the prothallium goes on pro-
ducing them as long as it exists j but at a
period somewhat later than that of the
earlier antheridia, there appear near the
middle, at the front of the under surface of

FERNS.

[ 322 ]

FIBRINE.

Fig. 240.

the protliallium, other cellular bodies, of
more complex structure, which are the
(trchegoma or ovule-like bodies. The arche-
goniuin consists of a cellular papilla, com-
posed of a few colourless cells, with a canal
running- down its centre (an intercellular
passage), leading to a cell (embryo-cell) at
the bottom, contained in a cavity (embryo-
sac) in the substance of the prothalliuin.
The ciliated spiral filaments make their way
down this canal, like the pollen- tubes
through the micropyles of Phanerogamous
ovules ; and then the embryo-cell becomes
developed into an embryo, which soon
exhibits rudimentary leaves and rootlets,
bursts out from the cavity of the prothal-
lium, which decays away, and grows up
into the ordinary leaf-bearing
stern of the Ferns (fig. 240).
The prothallia bear a vari-
able number of archegonia,
but not nearly so many as of
antheridia ; and they exhibit,
in most fully-developed spe-
cimens, a number of effete
organs of both kinds, which
are readily distinguished by
the deep-brown colour as-
sumed by the membranes Pteris, seedling,
bounding their cavities.

The characters of the prothallium of the
Ophioglossacece differ somewhat from the or-
dinary forms : the prothallium is developed
in the soil, several inches below the surface,
and is of a whitish-yellow colour internally,
being destitute of chlorophyll and starch ;
its external surface is brown. The anthe-
ridia are chiefly produced upon the upper
side, the archegonia below, both immersed
in the substance of the prothallium. The
spermatozoids are described as being larger
than in Polypodiaceae.

The Ferns produce also gemmce on the
leaves of full-grown plants; and even the
prothallia are capable of vegetative mul-
tiplication ; for if their archegonia are all
abortive, they go on vegetating for a long
time, and produce new prothallia, by some
of their marginal cells budding out and re-
peating the original mode of growth of the
spore itself. These innovations usually bear
antheridia alone, and not archegonia.
The Ferns are divided into six orders.
GLEICHENIACEJE. Sori dorsal, of few
thecee, naked ; thecae opening vertically by
a broad transverse complete annulus.

POLYPODIACEJE. Sori dorsal or margi-
nal, subglobose ; thecae numerous, with 01

without an indusium, usually stalked, more
or less completely surrounded by a vertical
annulus, and bursting transversely (except
in Hymenophylleae).

OSMUNDACE.E. Thecse two-valved, open-
ing across the apex, with a short horizontal
annulus ; vernation circinate.

SCHIZ^ACE^E. Thecae two-valved, open-
ing down the side, crowned by a complete
operculiform annulus ; vernation circinate.

MABATTIACKSB. Thecae opening by a
lateral slit or a pore at the apex; no annu-
lus, usually united into concrete masses
(synangia) ; vernation circinate.

OPHIOGLOSSACECE. — Thecae deeply two-
valved, opening down the side nearly to
the base ; no aunulus ; vernation erect.

BIBL. Berkeley, Crypt. Hot. 507 ; Presl,
Pteridograph. 1838;Payen,J?or5. Cryptogam.
1850; Biachoff,Kryptoffam. Gewacfae,182&;
Mohl, Martins' a Plant. Cryptog. Brasil. ;
Moore, Index Filicum & Handb. of Br. Ferns ;
Newmtai^Br.Ferns • Henfrey, Devel. of Ferns
from Spores, Linn. 2Vww.xxi.117, 1853 ; Re-
product, of Cryptogamia, Ann. N. H. 1852 ;
Hofmeister, Entwickelung, Scichs. Ges. 1857,
v. ; JReess, Jahr, wiss. Bot. v. I860 ; Stras-
burger, Befruchtung, Jahr. wiss. Bot. 1809,
vii. 390 j Kny, Monatsb. Berl. Akad. 1809 ;
id., Jahr. wiss. But. vii, 1 j Janczewsky, Bot.
Zeit. 1872,418; Sachs, Bot. 415: Hooker,
Syn. Filic. (figs, of all gen. and description of
all species} ; Kny, Ann. N. H. 1870, v. 233 ;
Strasburger, ibid. 1870, v. 331 j Smith, Hist.
Filic. 1875; Waldner, Ferns of Germany,
1880 ; Blair, European Ferns, 1881.

FIBRINE. — Fibrine exhibits very nume-
rous line fibres ; and is soluble in, or rendered
so transparent by acetic acid, as to be
invisible. Its chemical relation to the
other proteine-corupounds has not been
satisfactorily determined. A substance re-
sembling fibrine in many of its characters,
if not identical with it, occurs upon the
surfaces of inflamed membranes, &c. ; in
these cases it generally includes the other
elements of inflammation, and almost al-
ways a number of minute granules of fat.

Fibrine is coloured by the test-liquids of
Millon and Pettenkofer.

According to Schmidt's experiments,
fibrine does not pre-exist in blood, but is
formed by the chemical combination of
a fibrinogenous substance occurring in the
blood-plasma with a fibrino-plastic matter
contained in the blood-corpuscles, which
escapes from them ; more recently, Schmidt
considers the separation of fibrine to depend

F1BROINE.

[ 323 ] FILAMENTOUS STRUCTURES.

upon the action of a ferment (see Frey,
Hist. 16, and M. Baker, Phi/s. 93).

The fibrinous plasma of the lower animals
resembles fibrine in many respects, but does
not separate in fibres.

FIBROINE. — The principal chemical
constituent of silk, cobwebs, and the horny
skeleton of sponges ; but the latter is now
considered to be composed of a new sub-
stance, spongine. In the pure state, it is
white, insoluble in water, alcohol, ether,
acetic acid, and ammonia.

BIBL. That of CHEMISTRY, ANIMAL.

FIBRO-PLASTIC TISSUE. See TIS-
SUE, FIBRO-PLA-STIC.

FIBROUS and FIBRO-VASCULAR
BUNDLES. See TISSUES, VEGETABLE.
FIBROUS STRUCTURES OF PLANTS.

—This term is somewhat equivocal, and
requires a little explanation here. In com-
mon language all vegetable substances are
termed fibrous which can be separated into
more or less fine threads possessing a certain
degree of tenacity ; special examples are
furnished by those forming the materials
for textile fabrics. But the anatomical or
microscopical structures comprehended here
are exceedingly varied, including not only
liber-fibres, but spiral vessels, and even
hairs. Thus, Flax (PI. 28. fig. 2) is the
liber of Linum usilatissimum ; Hemp (PI.
28. fig. 6) of Cannabts ; Jute (PL 28. fig. 3)
of Corchorw capsularis &c. ; Puya (PL 28.
fig. 26) of Bcehmeria Puya, and the material
of Chinese grass cloth (PI. 28. fig. 25) of
Bcehmeria'nivea') Coir (PL 28. fig. 4) the
liber-like fibre of the husk of the cocoa-nut j
Manilla hemp (PL 28. fig. 7) of the fibro-
vascular bundles of Musa textilis ; New-
Zealand flax of Pbormium tenax ; Espar-
to grass of Lygeum esparto ; and Cotton
(PL 28. fig. 1) consists of the hairs covering
the seeds of species of Gossypium. These
and similar substances are also spoken of
under LIBER, HAIRS, and under their re-
spective heads.

In botanical language, the word fibre has
come into use in two very different senses.
First, any long cell attenuated to a point
at both ends, and with its walls thickened
with ligneous secondary deposits, is called a
Jihre by some authors. Thus the term woody
fibre is applied to the shorter cells of this
kind which make up the substance of most
solid woods; while the term liber-fibre is
applied (with more justice) to the often
extremely elongated wood-tubes which form
the elements of the liber of Dicotyledons

and the woody part of the fibre-vascular
bundles of the Monocotyledons. (See TIS-
SUES, VEGETABLE.) The characters of
structures of this kind will be given under
LIBER and WOOD. Secondly, the term
Jib re is applied to the secondary deposits
upon the walls of cells, vessels, ducts, &c.,
which, instead of forming continuous pitted
layers, take the pattern of spiral or analogous
lines, and, by increasing in consistence, sub-
sequently form real fibres, often elastic and
unrollable, of firmer substance than the
cell-wall upon which they were originally
deposited. The numerous modifications of
these fibrous deposits upon the walls of cells
are spoken of under the heads of SPIRAL
STRUCTURES, VESSELS, and SECONDARY
DEPOSITS.

It must not be omitted here that the walls
of many cells and liber-fibres, which appear
at first sight to be composed of homogeneous
laminae, may often be made to exhibit spiral
streaks, by the use of reagents aud macera-
tion ; indeed they present themselves during
the natural dissolution of the membranes
of some of the Oscillatoriaceae (AINACTIS,
SCHIZOSIPHON — PL 8. figs. 13, 15). Hence
some authors have recently recurred to the
old notion that all vegetable membranes are
formed of fibres cemented or blended toge-
ther. This is again strongly combated by
others, as regards the primary membrane of
cells. We enter more particularly into the
details under the article SPIRAL STRUC-
TURES of Plants.

FI'CUS, Linn. (Figs).— A large genus
of Urticacese (Dicotyledons), some of which
possess a remarkably thick epidermis and
curious pseudo-glandular structures con-
nected with it. Ficus elastica, one of the
plants yielding india-rubber, now commonly
grown in pots in rooms, is a good example.
The clavate bodies (PL 48. fig. '27) of Meyen,
developed in cavities in the leaf, beneath
the epidermis, contain crystalline deposits.
(See GLANDS and RAPHIDES.)

FILAMENTOUS STRUCTURES OF
PLANTS. — This name would be more appli-
cable than fibrous structures to such sub-
stances as COTTON, which consists of elon-
gated hairs (PL 28. fig. ]), and indeed. to all
elongated cellular filaments with thin and
collapsing walls. It would include all long
vegetable hairs, like those forming the
coma on many seeds (Poplars, Asclepias,
Gossypium, £c.) ; also those forming felty
coatings on the epidermis, as in many Com-
posite, &c. It is also applicable to the

Y2

FILARIA.

[ 324 ]

FISSIDENTE/E.

cells of most of the Confer void Algae, to
the mycelium (flocci) of Fungi, and to the
medullary layer of the lichens. Many
other instances will suggest themselves to
the microscopist.

FILA'RIA, Miill.— A genus of Entozoa,
of the order Nematoidea.

Char. Body filiform, very long, nearly
uniform ; head not distinct from the body ;
mouth round, or triangular, naked or with
papillae ; white, yellowish, or red, from 48
to 100 times as long as broad; oesophagus
short, tubular, narrower than the intestine ;
anus terminal, or nearly so ; spicula two,
of unequal size, more or less twisted ;
vulva situated very near the anterior extre-
mity.

Several species, many of which have been
imperfectly examined. They are most
commonly found in the abdominal cavity
and between the peritoneal folds of mam-
malia and birds, in the blood and the air-
cells of the latter, sometimes in the subcu-
taneous cellular tissue. Species are also
met with in reptiles, fishes, and insects.

F. medinensis. The hair- or Guinea- worm.
Common in the intertropical regions of the
old world. Length 6 to 10" ; breadth 1-20
to 1-10". F. bronchialis occurs in the human
bronchi; F. lachrymalis in the lachrymal
gland; F. oculi (papillosa) in the globe of
the eye, or beneath the conj unctiva ; F.
immitis in the heart of the dog ; F. rhyti-
pleurites in the cockroach, &c.

F. sanguinis is capillary, uniform, with-
out papillae, the neck narrowed, the tail of
female simple, bluntly pointed, the vulva
close to the head, and the anus near the tip
of the tail ; length of adult 3£", of embryos
rsir-TV". It is found in the immature
form in human blood and urine, in chyluria
and endemic haematuria. The adult form
occurs in the subcutaneous connective tissue
of the scrotum, &c.

Two species occur in fresh water, under
the leaves of aquatic plants :

F. aquatilis. Fern, white, constricted
behind the spherical head ; tegument not
striated; oesophagus capillary, very long,
sinuous ; tail gradually narrowed to a
curved point ; vulva anterior to the middle
of the body ; length 3-10 to 4-10"; breadth
1-250".

F. lacustris. Fern, reddish-white, slightly
narrowed in front, but without a constric-
tion ; mouth very small, lateral, and oblique;
oesophagus filiform, very long, nodose at its
origin j tail conical, obtuse, terminating

obliquely in a very small point ; tegument
not striated ; vulva behind the middle ;
length 1-2" ; breadth 1-140".

BIBL. Dujardin, Helminth. 42 ; Diesing,
Helminth, ii. 263 ; Kiichenmeister, Para-
siten, 304; Lewis, San. Comm. Sth Hep.,
Calcutta, 1872; Leuckart, Parasit. 1879,
65 (fig.); Gruby and Delafond, Compt. rc/ifl.
xlvi. 1217 ; Leidy and Welch, Mn. Mic. Jn.
1873, 157; Ann. N. H. 1878, ii. 199;
Cobbold, Parasites, 1879 {most complete
literature).

FILELLUM, Hincks.— A genus of ma-
rine Hydroid Polypi, fam. Lafoeidae,

1 species: F. serpew, common on the
larger Sertulariidae, especially S. abietina.

BIBL. Hincks, Brit. Zooph. p. 214.

FIR. See PINUS, CONIFERS, and
WOOD.

FISCH'ERA, Schwabe.— A genus of
Oscillatoriaceae (Confer void Algae).

Char. Filaments irregularly branched,
composed of uniserial cells, with interstitial
subglobose cell; surrounded by mucus,
forming an amorphous gelatinous stratum.

F. thermalis. On the walls of warm
springs (Rabenhorst, Fl. Alg. ii. 285).

FISSIUEN'TE^E.— A family of opercu-
late Acrocarpous (sometimes cladocarpous)
Mosses, of gregarious or caespitose habit,
with simple or much-branched stems. The
leaves are amplexicaul (fig. 242), composed
of minute parenchymatous cells, closely are-
Fig. 241. Fig. 242. Fig. 243.

Fissidens bryoides.

Fig. 241. A plant of F. bryoides. Magn. 5 diams.
Figs. 242 & 243. Leaves detached. More magnified
to show the appendage.

FISSIDENS.

[ 325 ]

FLAX.

olated, often very papillose, produced at the
back and point into a lamina beyond the
leaf (figs. 243-246), whence three parts
are distinguished in the latter : — 1, the
true horizontal blade ; 2, the dorsal lamina,
arising vertically from the back of the nerve;
3, the apical lamina, the preceding lamina
produced beyond the true horizontal blade

Fig. 244.

Fig. 247.

Fiasidens bryoides.

Figs. 244, 245, 246. Sections of 243, at various heights
from the base.
Fig. 247. Fragment of peristome. Magn. 100 diams.

of the leaf in a two-edged form, on each
side of the nerve. Capsule equal, rarely
annulate. British genus : FISSIDENS.

FIS'SIDENS, Hedw.— A genus of Fissi-
denteee. Character that of the family. In-
florescence monoecious or dioecious, terminal
on the main stem or on short secondary
branches. Montague has separated the
species with an entire calyptra under the
generic name of Conomitrium.

F. bryoides (fig. 241), not uncommon, is
a most elegant little moss.

BIBL. Wilson, Bryol. Brit. p. 301.

FISSURI'NA, Reuss. — A compressed
Lagena, with slit-like aperture. It has the
same relation to Lagena that Lingulina has
to Nodosaria.

BIBL. Reuss, Monogr. Lagen. in Sitz.
Ak. Wiss. Wien, xlvi. i. 1863.

FISTULI'NA.— A genus of Polyporei
(Hymenomycetous Fungi), characterized by
the papillae of the fleshy hymenophorum
being at length elongated and forming
distinct tubes, which call to mind those
of Solenia.

Fistulina hepatica occurs not unfrequently
on old oaks, on which it sometimes attains

an enormous size, and when well dressed is
excellent for culinary purposes. The flesh,
when cut resembles that of beet-root.

BIBL. Huss. i. t. 65; Berk. Outl 257,
tab. 17. fig-. 1 ; Cooke, Handb. 292.

FLABELLI'NA, D'Orb.— One of the
Nodosarince. It is dimorphous — that is,
having two successive plans of growth : —
the first spiral, like that of Cristellaria ; the
later rectilinear, like that of Nodosaria, or
rather of Frondicularia, which latter it
resembles in its chevron-shaped flattened
chambers. It differs from Frondicularia in
an eccentricity, or tendency to coil, in the
earliest chambers, and thus connects the
Stichostegian with the Helicostegian groups.
It is to Frondicularia as Vaginulina, Mar-
gmulina, and Planularia are to Nodosaria.
To many large flat Cristellarice (C. cassis)
semigeniculate chambers give a Flabelline
feature ; but pure Flabettince are rare in the
recent state (Batsch figured one) and in
Tertiary strata. In the Chalk (Ft. ruaosa,
PI. 23. fig. 38), Gault, Lias, and other
Secondary strata, Flabelline abound.

BIBL. D'Orbigny, For. Foss. Tien. 92;
Morris, Brit. Foss. 35 ; Parker and Jones,
Ann. N. H. 3. xii. 136 ; Carpenter, Introd.
For. ICO, 164.

FLAGELLA'TA. See INFUSORIA.

FLANNEL, NATURAL.— This term
has been applied to sheets or layers of a
harsh fibrous texture, sometimes found
covering meadows, rocks, &c. after an inun-
dation. It consists of the interwoven fila-
ments of Confervse, with adherent or en-
tangled Diatomaceae, Infusoria, crystals of
carbonate of lime, &c. To the naked eye
it closely resembles a piece of coarse or
loosely woven cloth. Similar layers are
frequently found upon the margins of pools
during the summer. As the water evapo-
rates, the Confervas and other organisms
remain supported upon the stems of rushes,
or blades of grass, and, when dry, form the
yellowish, greenish, or greyish layers of the
so-called natural flannel.

See PAPER, METEORIC.

FLAX. — The liber-fibres from the stems
of the Flax-plant, Linum usitatissimum(nsk.
ord. Linacese, Dicotyledons). Under the
microscope, the fibres (PI. 28. fig. 2) are
readily distinguished from those of Cotton
by the form and consistence, — being round
and attenuated to a point at each end, and
of a firm woody consistence, which prevents
them from collapsing, and having pits in the
wall. New-Zealand Flax is a totally differ-

PLEA.

[ 326 ]

FLORIDE.E.

rnt substance (PHORMIUM). See FIBROUS
STRUCTURES of Plants, and LIBER.]

FLEA. See PULEX.

FLINT. — This is a subtranslucent variety
of silica, forming nodules or bands in most
limestones. The organisms in flint are the
same as those met with in the chalk or other
limestone of which the flint forms part, as
a pseudomorphic replacement of the original
amorphous carbonate of lime by silex,
generally where decomposing organic matter
induced the conditions of change.

Much of the flint of the South of England
has been formed out of the calcareous mud,
crowded with small sponges, spicules, and
Foraminifera, which hold the same position
in the flint as they did in the cretaceous
ooze. Large sponges are often included,
with shells of Mollusks and Echinoderms,
scales of Fishes, and sporangia of Desrni-
diaceae, formerly recorded as distinct organ-
isms (Xanthidia).

The crystallized calcite of Echinoderms
and some shells is not replaced by silex in
limestones, but remains as cavities in ex-
posed flint-masses. Many varieties of lime-
stone, viz. polyzoan limestone in France,
freshwater limestone in France and Turkey,
orbitoidal limestone in Jamaica, oolitic
limestone at Portland and elsewhere, are
converted into flint, hornstone, &c. of fine
or coarse grain according to the constitution
of the original limestone.

"Wallich has suggested that chalk-flints
are due to the nearly continuous proto-
plasmic layer among extensive sponge-
growths having become silicified.

In the examination of flint, thin sections
should be made by grinding and polishing ;
some kinds exhibit the organisms contained
in them best by reflected, others by trans-
mitted light. Some specimens, in which
they are abundant, will exhibit them well
in chips removed by a hammer.

See AGATE and CHALK.

BIBL. That of AGATE and CHALK ;
Ehrenb. Ann. N. H. 1838, ii. 162 ; Turner,
Phil Mag. 1833 ; Ansted,Ann. N. H. 1844,
xiii. 248 ; Bowerbank, ibid. 1847, xix. 240 j
Charlesworth, Geol.Jn. 1847, i. 29; Church,
Proc. Chem. Soc. 1862 ; id. Chem. News, v.
95, and Phil. Mag. (4) xxiii. 95 ; Sutherland,
Geol. Mag. ii. 220; Johnson, "Flint? 1871 ;
Jones, Proc. Geol. Assoc. iv. 439 ; Wallich,
Qu. Jn. Geol. Soc.. Feb. 1880: Sollas, -4ww.
N.H.

FLORID'E^E or RHODOSPO'REyE.—
An order of Algae. Red sea- weeds, some

of the common species of which must be
familiar to every one, as the delicate feathery
or leaf -like plants brought away by most
visitors to the sea-coast ; and the red colour,
more or less permanent or fleeting, is a
pretty general characteristic of this order
— varying however to purple, brown, and
mixed tints of red, green, and yellow, and
dirty white ; the green colour of the chloro-
phyll being often obscured by a red pigment,
phyco-erythrine. They chiefly grow in deeper
water than the other sea-weeds, and are met
with in finest and darkest colour in deep
tide-pools of sea-water, especially on the
side facing the north, where they are over-
hung by the larger dark-coloured Algae, and
thus shaded from the sun's rays. The greater
number do not grow more than six inches
high, few more than two feet. The simple.' t
foims are filaments composed of cylindrical
cells attached end to end ; they next rise
to a gelatinous or cartilaginous expansion,
composed of such filamentous structures
adherent in layers, and forming a com \ act
frond of definite shape. These are said to
be of filamentous structure. Others have the
frond composed of a number of polyg< n;;l
cells, evenly arranged, and with thick walla,
or, as some state, an intercellular substance
binding them all together into amass ; these
are technically said to be of cellular fttrm-fure.
Sometimes all the cells of the frond con-
tain colouring-matter, sometimes only those
of the surface, or of a shallow superficial
stratum.

The general external appearance of the
Red Sea-weeds is very varied. Sometimes
the fronds are like little leafless bushes ; at
others they form broad laminae ; sometimes
the lower part is stalk-like, and the upper
parts spread into leaf-like lobes. In Ucles-
seria we have a close imitation of a regu-
larly formed leaf of one of the l.igher plants.
The leaf-like forms are either simple, lobed,
or exquisitely pinnate or feathered ; and the
Rhodosperms of warmer climates exhibit
most elegantly reticulated fronds. Some of
these plants deposit carbonate of lime in
their tissues in such quantity that they
become quite stony, so that, the vegetable
form alone remaining, they are commonly
mistaken for true corals (see CORAL). By
placing these corallines and mdlipores in
vinegar or dilute hydrochloric acid, the lime
is removed, and the cellular vegetable orga-
nization may be recognized. The tiopical
forms of the corallines are far more varied
and beautiful than our own.

[ 327 ]

FLORIDE^E.

Red or colourless albuminous crystalloids
are found in some of the Floridese.

Three kinds of reproductive structures
occur in these plants, viz. : — 1, tetraspores ;
2, spores ; 3, spermatozoids or antherozoids.

The tetraspores or tetragonidia. These
structures are of similar organization
throughout the order. They consist of an

Fig. 248.

Bhynchococcus coronopifolius.

Section of the frond with tetraspores.

Magnified 200 diameters.

oblong or globular external cell or sac (peri-
spore), at first filled with granular contents,

Fig. 249.

Ptilota plnmosa.

Section of frond with tetrasporea.
Magnified 200 diameters.

which contents subsequently separate into
four portions, called sporules, either by
three transverse fissures (fig. 248) ; by two
fissures at right angles, cutting them into
quarters like an orange ; or by tri-radiate
fissures which part them into the 'tetra-
hedral' group (fig. 249) so often found in
the division of spore- and nollen-cells : the
last two occur in the spherical tetraspores.
The tetraspores are rarely found collected in
any capsular structure ; but in the Corallines

Hildenbrant san-

(fig. 141), and in some few foreign genera,
they are grouped in hol-
low cases (conccptacles,
fig. 250). In many in-
stances, however, they are
found in pod-like bodies
(stichidia, PL 4. fig. 13 6),
either formed by meta-
morphosis of portions of
the lobes or lobules of the
frond (Plocamiuni) , or
arising independently on
it. In others the tetra-
spores are naked (CaUi- gectionofaconeep_
mammon), scattered over tacle containing tetra-
the sides or fixed at the tips spores,
of the branches. In the Magn< 50 ^am9'
majority of cases, however, these bodies are
immersed in the substance of the lobes or
lobules, not evident externally except by
the darker colour of the frond at the point
where they are collected; a lens is then
required for their detection ; they here
appear to be formed either of the cells of
the surface or of others immediately sub-
jacent. Harvey, Thwaites, Pringsheim, and
others regard these bodies as gemmules or
gonidia-, Decaisne, J. Agardh, and other
Algologists regard them as true spores.
Pringsheim states that in Ceramium they
grow up at once into a thallus.

The true spores are simpler structures
than the tetraspores, but mostly occupy a
more important position. They are never
scattered through the frond, but always
grouped in definite masses, generally enclosed
in a special capsule, conceptacle or cystocarp,
which is furnished with a closed tube or
trichogyne (PL 4. fig. 12 c). In fertilization,
the spermatozoids conjugate with the tricLo-
gyne (PL 4. fig. 12 a). Its basal cell then
subdivides, the new cells forming a sporife-
rous heap ; as in Nemaleon (and Batracho-
spermum). Or, the trichogyne-cell' takes
no direct part in the formation of the spores,
which are produced after fertilization in
laterally arising new cells, as in the Cera-
miaceae &c. In Dudresnaya the elongated
trichogyne is spiral at the' base. After its
fertilization, cells sprout from beneath it,
and elongate to form connecting tubes,
These pass over the ends of the fructiferous
branches, which are short with an enlarged
terminal cell, becoming soldered with them
at the points of contact, the contents being
mixed : each connecting tube conjugates
with several of the fertile branches.

The simplest form of the spore-fruit con-

FLORIDE^E.

[ 328 ]

FLOSCULARIA.

sists of spherical masses of spores, attached to
the wall of the frond, or iiuhedded in its
substance without a proper conceptacle, in
which latter case the cells surrounding the
mass of spores are devoid of colouring-
matter : such a fruit is called a favellidium,
and occurs in Halymenia ; and the same name
is ordinarily applied to fruits of similar struc-
ture not perfectly immersed, such as those of
Gigartina, Gelidium, &c., where they form tu-
bercular swellings on the lobes. In some cases
the tubercles present a pore at the summit,
when mature, through which the spores find
exit. When such a fruit is wholly external,
as in Ceramium and Cattithamnion, it is
called a favella. The coccidium, charac-
teristic of Delesseria (PI. 4. fig. 5e), Nito-
phyllum, &c., which is nearly related to this,
either occurs on lateral branches, or is ses-
sile on the face of the frond, and consists of
a hollow case with thick cellular walls, con-
taining a dense tuft of angular spores at-
tached to a central column. It is generally
imperf orate, but occasionally exhibits a
pore through which the spores escape. The
ceramidium is the most complete form
of the conceptacular fruit, and is an ovate
or urn-shaped case, furnished with an apical
pore, and containing a tuft of pear-shaped
spores arising from the base of the cavity.
The walls are usually thin and membranous,
and the hollow space considerable, as in
Polysiphonia, Laurencia, Dasya (PI. 4. fig.
9 c), &c.

From the account given by Pringsheim,
of Ceramium, it would appear that these
(capsule-) spores first produce a kind of pro-
thallium, somewhat in the manner of the
higher Cryptogamia.

Peculiar bodies, forming external warts,
and composed entirely of vertical fibres,
but without spores, called nemathecia, are
sometimes confounded with the concepta-
cular fruit, and are probably immature forms
of it.

The spermatozoids are found in peculiar
structures, to which the name of antheridia
has been applied, from the supposed analogy
to the organs so called in the other Crypto-
gamous plants. The antJieridia are pro-
duced pretty much in the same situations
as the other organs of fructification, and are
often developed on different individuals.
They are collections of very small colour-
less cells (PI. 4. fig. 126) ; sometimes col-
lected into a bunch, as in Griffithsia ; some-
times enclosed in a transparent tube, as in
Polysiphonia ; clothing a kind of irregularly-

shaped flat plate, as in Laurencia ; or occu-
pying portions of the general surface of the
thallus. Each of the minute cells contains
a rounded motionless spermatozoid.

Synopsis of the Families.

RHODOMELACE^:. Frond cellular, areo-
lated or articulated. Ceramidia external.
Tetraspores in rows, immersed in ramuli, or
contained in proper receptacles (stichidia).

LAUBENCIACE^E. Frond cellular, con-
tinuous. Ceramidia external. Tetraspores
scattered, immersed in the branches and
ramuli.

COBALLINACE^J. Frond calcareous or
crustaceous, rigid. Ceramidia external, con-
taining the tetraspores.

DELESSERIACE^E. Frond cellular, con-
tinuous, areolated. Coccidia external. Tetra-
spores collected into definite clusters (tori).

RHODYMENIACEJE. Frond cellular, con-
tinuous, the superficial cells minute. Coc-
cidia external. Tetraspores scattered through
the frond, or forming undefined, cloud-like
patches.

CRYPTONEMIACE.E. Frond fibroso-cellu-
lar, composed of articulated fibres connected
together by gelatine. Favellidia immersed
in the frond or sub-external. Tetraspores
immersed in the frond.

CERAMIACEJE. Frond filiform, consisting
of an articulated filament, simple or coated
with a stratum of small cells. Favettce
naked berry-like masses. Tetraspores ex-
ternal, or partially immersed.

PORPHYEACE^). Frond plane and ex-
ceedingly thin, or tubular and filiform, of a
purplish colour, with oval spores in sori,
and tetraspores scattered over the frond.

BIBL. Harvey, Mar. Algce, 1849, & Phyc.
Brit. ; Kiitzing, Phycol. gen. ; Thuret, Ann.
Sc. Nat. 3 se'r. xvi. 5, 4 ser. iii. 5 ; Derbes
and Solier, ibid. 3 se'r. xiv. 261, 4 se'r. v.
209; Pringsheim, Berl. Ber. 1855; Ann.
Sc. Nat. 4 se'r. iii. 363 ; Bot. Zeitung, xv.
784; Henfrey-Masters, Bot. 1878; Bornet
and Thuret, Ann. Sc. Nat. 1867, vii. 166 •
Rosanoff, Compt. Rend. 1866; Cohn,
SchuLtze's Archiv, iii. 24; Askensky, Bot.
Zeit. 1867 (col. matter); Solms-Laubach
Bot. Zeit. 1867; Sachs, Bot. 1874, 291.

FLOSCULA'RIA, Oken, Ehr.— A genus
of Rotatoria, of the family Floscularieea.

Char. Attached ; eyes two, red ; carapace
single; rotatory organ divided into more
than four lobes, with elongated cilia radia-
ting from their extremities.

FLOSCULARLEA.

[ 329

FORAMINIFERA.

Eyes sometimes absent in the adult ani-
mals. Sheath or carapace frequently so
transparent as to be scarcely distinguish-
able. Rotatory organ with five or six lobes ;
the number, however, appears variable ; for
Ehrenberg states in one place that the lobes
are five or six, in another that they are
always six. The so-called proboscis is pro-
bably only one of the lobes of the rotatory
organs ; freshwater.

F. ornata, E. (PL 43. fig. 32). Carapace
hyaline; rotatory lobes six (Ehr.), five
(Duj.j, with long cilia, but no central pro-
boscis ; length 1-108".

Lobes of rotatory organ thickened at the
ends.

F. proboscidea, E. Carapace hyaline;
rotatory organ 6-lobed, with short cilia
surrounding a central proboscis; length,
when extended, 1-18". Teeth (fig. 33).

F. campanulata, Dob. Differs from F.
ornata, Ehr., in having five lobes, and these
flattened ; length, when extended, 1-50".

F. cornuta, Dob. Rotatory organ 5-
lobed, one of the lobes with a narrowed,
not ciliated cornu attached, arising from its
outside ; cilia long ; length, when extended,
1-40".

Other species.

These exquisitely beautiful animals are
found adhering to aquatic plants, as Con-
ferva, Ceratophyllum, &c.

BIBL. Ehr. Inf. 407; Duj. Inf. G09;
Dobie. Ann. N. H. 1849, iv. 233 ; Cubitt,
Mn. Mic. Jn. 1&69, ii. 143 (PL), and 1871,
vi. 83 (new spec.) ; Weisse, Sieb. fy Koll.
Zeitsch. xiv. 107 (PL) ; Hudson, Jn. Mic.
Soc. 1881, i. 4.

FLOSCUL ARLE'A.— A family of Rota-
toria.

Char. Furnished with a carapace or
sheath ; rotatory organ single, with a flexu-
ous, lobed or divided margin.

The cilia are often long, and only vibrate
occasionally, mostly remaining rigidly ex-
tended.

Genera.

Eyes absent 1. Tubicolaria.

Eye single 2. Stephanoceros.

(9 , , -, j single.... 3. Limnias.

Eyes j Rotatory 1 \ aggregate 4. Lacinularia.
two 1 organ ) 4-lobed 5. Melicerta.

(5- or 6-lobed , 6. Floscularia.]

The eyes in some of the genera (Stepha-
noceros and Floseularia) disappear in the
adult state ; so that they must be looked for
in the young, or even in the partly hatched
ova, in which they may often be distinctly
teen.

BIBL. Ebrenberg, Infus. p. 398.

FLUKE. See DISTOMA.

FLUS'TRA, Linn. (Sea-mat).— A genus
of Cheilostornatous Polyzoa, family Flus-
tridae.

Char. Polyzoarium plant-like, foliaceous,
flexible ; cells in contact, alternate, in seve-
ral rows, and on both sides of the polypi-
dom ; aperture transverse, semicircular or
lunate, valvular and subterminal. Marine.

F. foliacea. Cells narrow at the base,
rounded at the end, with scattered marginal
spines. Common; about 4" high.

F. chartacea. Cells oblong, slightly
broader in the middle ; lateral margins with
a single minute spine.

About 1" in height.

F. truncata. Cells linear-oblong, truncate
at the end, margins without spines : 4-5"
high.

F. carbasea = Carbasea papyrea ; F. am-
cularis=Btigulaflabellata ; F. Murray ana =
Bugula Murr. ; F. membranacea} coriacea,
and lmeata = Membranipora m.} c., and I.

BIBL. Johnston, JBr. Zooph. 342 ; Reid,
Ann. N. H. 1845, xvi. 385; Busk, Brit.
Mus. Catal 47 ; Hincks, Polyz. 114.

FLUS'TRADJE.— A family of Cheilo-
stornatous Polyzoa.

Distinguished by the expanded, foliaceous,
flexible and erect polyzoary, with its nu-
merous contiguous cells. Two genera.

Fhistra. Cells on both sides.

Carbasea. Cells on one side only.

BIBL. Busk, Mar. Polyz. (Br. Mus.} 46.

FLUSTREL'LA, Gray.— A genus of
Ctenostomatous Polyzoa, of the order In-
fundibulata, and family Alcyonidiidse.

In crusting, cells radiating or alternate,
the circumference with setae ; orifice rect-
angular.

F. hispida. Common near low-water
mark upon Fucus serratus. Polyzoary
brown, fleshy.

BIBL. Johnston, Br. Zooph. 363; Red-
fern, Qu. Mic. Jn. vi. 96; Hincks, Polyz.
504.

FLY. See MUSCA.

FOLLICULA'RIA=^Tm«.

FONTINA'LIS, L.— A genus of pleuro-
carpous Mosses.

P. antipyretica, greater water-moss; in
rivulets. F. squamata. (Wilson, Bryol
Brit. 422.)

FORAMINIF'ERA.— An order in the
Animal Kingdom, belonging to the Sub-
kingdom Protozoa, and class Rhizopoda.

Char. Gelatinous, structureless, usually

FORAMINIFERA.

[ 330 ]

FORAMINIFERA.

microscopic marine animals, contained
within calcareous shells, from orifices or
pores in which tine retractile processes are
emitted, by which locomotion and prehen-
sion are performed.

The shells are sometimes simple, con-
sisting of a single cell or chamber (Uiiilo-
cular, Monothalamous, or Monostegian), as
in Uniloculina, Cornuspira, Ovulites, some
Trochammina, Layena, Orbulina, Spirillina',
but the cells are usually aggregated into a
compound shell (Multilocular or Polytha-
lamous). In some they are arranged end
to end in a straight row (Stichostegian) , as
in some Articulina, some Lituoke, Nodosaria,
Frondicularia. In others the single row is
rolled into a spiral (Helicostegian, Nauti-
loid, Turbinoid, or Fusuline), as in Penero-
plis, Lituola, Cristellaria, Polystomella, 670-
biyerina, the JRotalina, Nummulites, Fusu-
lina. Or the cells are arranged in two
alternate rows, spirally coiled (Entornoste-
gian), as in Valculma, Bulimina. Some-
times the cells form two or three alternate
rows, but not spirally coiled (Enalloste-
gian), as in Polymorpldna, Uvigerina, Textu-
laria ; whilst in others the cells are arranged
around an (imaginary) axis, upon two or
more opposing faces (Agathistegian), as in
Miliola, Chilostometta. There are also dis-
coidal shells with alternately concentric cells
(Cyclostegian), as Orbitolites and Cyclo-
clypeus. Many modifications, with di-
morphic and even trimorphic modes of
growth, also exist j thus Textularia an-
nectens (PI. 23. fig. 62) is helicostegian at
first, enallostegian subsequently, and sticho-
stegian at last ; whilst Biyenerina and Cla-
vulina (PI. 23. figs. 50 & 61) have only the
alternate and linear modes of growth ; and
Spirolina (PI. 23. fig. 12) is first spiral and
then linear. Between the chambers are
septa, consisting of either single or double
plates, perforated by one or more apertures
(whence the name Foraminifera), the mar-
gins of which, are sometimes more or less
prolonged to form tubes, as shown in figs.
31 & 41. This tube is sometimes turned
inwards (entosolenian) . As the more re-
cently formed chambers are often larger
than the others, the shells are often more
or less conical or pyramidal. The lines of
j unction of the chambers, visible externally,
are called the septal lines ; these are some-
times sunk, sometimes raised into ridges.
Frequently the outer chambers extend
laterally beyond the inner, so as to conceal
them ; they are then said to be embracing.

In a few of the Foraminifera the sholls ar<>
composed of a number of perfectly distinct
cells, each with a separate outer orifice
(Dactylopora, PI. 23. fig. 53).

The plan of growth offers no solid ground
for the classification of these organisms ;
but the character of their shell-structure
serves better; for there are two distinct
kinds of shell : — one white, opaque, and not
traversed with tubules (" porcellaneous" and
" imperforate "), such, as the Miliolce ; the
other subtranslucent and tubular (" vitre-
ous " or " hyaline," and " perforate "), such
as Nodosarina, Bulimina, and Nummulites.
Shells of each kind, however, are liable to
become " arenaceous," by particles of sand
or minute organisms being taken up in their
structure, as Quinqueloculina, Lituola, Tro-
chammina, Valvulina, Textidaria, and

The surface of the hyaline shells presents
a punctate appearance, arising from the
presence of very numerous foramina, which
are the outer orifices of tubules passing
through the walls of the shell. The ar-
rangement of these tubules and that of an-
other set traversing the walls and the septa,
as well as, in fact, the general structure of
the shell, may be illustrated by a descrip-
tion of the shell of Operculina arabica (PI.
24. fig. 23), in which they have been
carefully traced by Mr. Carter. Here the
outer surface, after the removal of a green-
ish epidermic layer, is seen to be covered
with large and small papillae — the former
1-2150", the latter 1-8600" in diameter—
neither of which are present over the
septa or at the margin of the shell. Each
of the septa encloses within its walls two
calcareous tubes, spaces, or channels, ono
on each side — the intraseptal channels
(tig. 26) ; these are about 1-1900" in dia-
meter, and in their course give off two sets
of lateral branches, terminating upon the
two surfaces of the septum in which they
run. The tubes communicate at each end
with a network of smaller ones ; one set of
which ramifies in the upper, the other in
the under wall or margin of each chamber ;
these are the marginal plexuses (fig. 24 h) ;
and the former terminate upon the outer
margin of the shell (g g). The inner wall
of the chambers is pierced by innumerable
tubules about 1-9COO" in diameter, which
pass directly downwards from the small
papillae on the outer surface. In a vertical
section of the shell, in addition to these
minute tubes, seven, eight, or more parallel

FORAMINIFERA.

[ 331 ]

FORAMIXIFERA.

horizontal lines are seen (fig. 25 c) ; these
are the lines of contact of the layers com-
po.-ing the shell, or the lines of growth. The
margin of the shell is traversed by elongated
inosculating vessels, which cause the mar-
ginal portion to break up into calcareous
spicula (fig. 24), 1-237" long and 1-900"
broad. In a transverse section of the mar-
gin, more than 100 of these are seen, form-
ing a triangular bundle or cord (fig. 25 «),
the apex being directed towards the cham-
ber, the base outwards forming the free
rounded margin of the shell ; and parallel
to its side run the papillary tubes of the
chamber (fig. 25 b).

In addition to the common foramina and
the orifices of the marginal plexus, the
chambers, especially those which terminate
the series, are furnished with other larger
orifices opening externally; these are of
various forms and differently situated ; some-
times they are round, numerous, and
comparatively small; at others they are
single and large, circular, semicircular, or
lunate, £c.

The nature of the Foraminifera has been
very differently viewed. They were formerly
regarded as microscopic Cephalopoda, then
as Bryozoa (Polyzoa), and again as inter-
mediate between the Polypi and Echinoder-
mata. Dujardin's view, however, is now
sdopted, that their structure is very simple,
and that they are closely allied to the Arcel-
lina, the body being single and composed
of a simple sarcodic substance, without
the distinct separation of organs, the fili-
form processes (pseudopodia), which issue
from the various external apertures of the
shell being comparable with those of
Amoeba, Arcella, and other members of the
family.

The chambers contain a soft translucent
colourless substance ; and often one or more
minute, round, granular bodies (sarco-
blasts) are present. These appear to have
been sometimes regarded as nuclei. If the
corpuscles described by Hertwig and Schulze
as nuclei are really such, the Foraminifera
may be ranked as high as the Amcebina.

The nature of the contents of the intra-
septal and marginal vessels is doubtful;
Mr. Carter regards them as performing a
water-vessel function comparable to that
of the circulating system of the sponges
(Grantia) ; whilst Williamson and Carpenter
consider them to be filled with the organic
substance of the body.

The shells of Foraminifera are rarely

quite chitinous ; some have a chitinous base
with either a sandy or a calcareous coating.
Mostly they are altogether composed of
carbonate of lime, and therefore effervesce
with a dilute acid. By carefully acting
upon the recent organisms with muriatic
acid, in the proportion of a drop of the
strong acid to a watch glassful of water
containing them, the animal is left (PL 23.
fig. 32), retaining the general form of
the shell, which it has moulded upon it-
self.

In the tl porcellaneous " group the shell-
matter covers each segment of sarcode tent-
wise, the edges of the new chambers resting
on the outside of the older part of the shell.
In the "hyaline" group each segment is, in
many cases, fully enwrapped with shell,
except at the septal orifice, through which
the stolon connects the new and old seg-
ments. Besides this tubuliferous shell-layer,
many of the hyaline Foraminifera lay down
other coats, by the investing sarcode,
before new segments are set off; and
these supplementary layers not only form
ridges and tubercles, but also the " inter-
mediate skeleton," in which vessels or
canals, for the sarcode passing outwards,
are more or less prevalent, constituting the
" Canal-system."

Recent Foraminifera can be procured by
dredging, or sometimes from the sand of the
sea-shore. They often form white lines or
bands, between tide-marks. To separate
them, the sand should be washed in fresh
water, dried, and spread upon a piece of
black paper, or the black disk (!NTBOD.
p. xxvi), and examined as an opaque object;
when the shells, easily distinguished by
their forms, may be picked out by means of
a mounted bristle.

Or the dried sand may be stirred up with
water and allowed to settle ; the sandy par-
ticles will then subside, and the shells, from
their chambers being filled with air, may be
skimmed off' the surface ; or they may be
poured off through muslin, with" the 'dis-
turbed water, before all the sediment has
had time to settle.

In the fossil state, the Foraminifera
abound in Chalk, from which they may
be obtained in the manner directed under
CHALK ; in fact this substance constitutes
one of the best sources of them for exami-
nation. In other calcareous rocks or lime-
stones they are also extremely numerous.
Thus in the stones of which the buildings
in Paris are constructed, the shells of the

FORAMINIFERA.

FORAMINIFERA.

Miliolidee are so abundant, that this city
may be said to be built of them.

The Nummulites or coin-stones which
form mountains in the Mediterranean and
North-Indian regions, and of which the
pyramids of Egypt are principally composed,
are Foraminifera (PI. 24. figs. 21, 22).

Many clays, such as those of the Lias, the
Oolitic and Cretaceous series, and London
Tertiaries, those of Prussia, Belgium, Ma-
laga, San Domingo, &c., and many shelly
sands of Tertiary age in Suffolk, Italy, Ger-
many, France, New Zealand, Australia, and
elsewhere, also yield Foraminifera by careful
washing.

See the articles CHALK and RHIZOPODA.

Synoptical List of the Genera and Subgenera
of Foraminifera.

(The subgenera are placed in parentheses.)
Division A. IMPERFORATA.

Subdivision 1. CHITINACEA.

GROUP I. Test chitinous, imperforate.

Fam. 1. Gromidae.

Gromia, Dujardin; Lieberkuehtiia, Cla-
parede ; Shepheardella, Siddall.

Subdivision 2. CALCAREA (PORCEL-
LANEA).

GROUP II. Test calcareous, imperforate,
porcellaneous, and sometimes sandy ;
occasionally chitinous and sandy.

Fam. 2. Miliolidae.

a. MILIOLINA. — Bathysiphon, G. O. Sars ;
Sqttamulina, Schultze; Nubecularia, De-
france ; Miliola, Lamarck, Plate 23. fig. 1
( = Miliolina) Williamson); (Uniloculina,
d'Orb., PI. 23. fig. 2; Biloculina, d'Orb.,
PI. 23. fig. 3 ; Spirolocuiina, d'Orb., PI. 23.
fig. 7 ; Triloculina, d'Orb., PI. 23. fig. 4 ;
Quinqueloculina, d'Orb., PI. 23. figs. 5, 6;
Cruciloculina, d'Orb.) ; Cornuspira, Schultze,
PL 23. fig. 13 (Ophthalmidium, Kiibler) ;
Nummuloculina, Steinmann ; Hauerina,
d'Orb., PI. 23. fig. 8; Vertebralina, d'Orb.,
PI. 23. fig. 9 (Articulina, d'Orb., PI. 23. fig.
9); Fabularia, Defr.

b. ORBITOLITINA. — Peneroplis, de Mont-
fort, PI. 23. fig. 11. (Dendritina, d'Orb. ;
Spirolina, Lamarck, PI. 23. fig. 12.) Orbicu-
lina, Lam., PI. 23. tig. 19; Orbitolites,
Lam., PI. 23. fig. 17 ; Alveolina, d'Orb.. PI.
23. figs. 15, 16.

c. ? DACTYLOPORINA. — Ovulites, Lam. ;
Haploporella, Giiml>el(=Dactylma, Zbor. ?),
PI. 23. fig. 53; Dactyloporella, Giimb.
(=Dactylopora, Lamarck, in parte), PI. 23.
fig. 54 ; Thyrsoporella, Giimb. ; Gyroporella,
Giimb. ; Cylindrella, Giimb. ; Uteria,
Michelin ; Acicularia, d'Archiac.

Subdivision 3. ARENACEA.
GROUP III. Test calcareous and arenaceous.

Fam. 3. Astrorhizidae.

Psammosphcsraj Schultze ; Swosphwa,
Brady; Saccammina, M. Sars; Pilulina,
Carpenter; Storthosphara, Schulze ; Tech-
nitella, Norman ; Pelosina, Brady ; Asche-
monella, Br. ; Astrorhiza, Sandahl ; Dcndro-
phrya, Str. Wright; Rhabdammina, M.
Sars ; Jacuklla, Br. ; Hyperammina, Br. ;
Psammatodendron, Norman (MS.) ; Sage-
nella, Br. ; Botellina, Carpenter; Marsi-
pella, Norman ; Haliphysema, Bowerbank ;
Polyphrayma, Reuss.

Fam. 4. Lituolidse.

(These comprise sandy isomorphs of the
simpler types of the Hyalina, such as La-
gena, Nodosaria, Globigerina, Rotalia, No-
nionina, &c.)

Lituola, Lam., PI. 23. fig. 23 (Reophax,
de Montfort ; Haplophragmium, Reuss ; Ha-
plostiche, Rss. ; Placopsilina, d'Orb. ; Bdel-
loidina, Carter) ; Trochammina, Parker &
Jones, PI. 23. fig. 14( Hormosina,Bmdy ; Am-
modiscus, Rss. ; Webbina, d'Orb., PI. 23. fig.
21) ; Nodosinella, Br. ; Involutina, Ter-
quem ; Endothyra, Phillips ; Stacheia, Br. ;
Thurammina, Br. ; Hippocrepina, Parker ;
Cydammina, Br.

Fam. 5. Parkeridae.

Parkeria, Carpenter ; Loftusia, Brady.

Division B. PERFORATA (Vitrea vel

Hyalina).

GROUP IV. Tests of many of the larger
forms arenaceous, with more or less
of a calcareous perforate basis ; smaller
forms hyaline and perforate.

Fam. 6. Textularidae.

a. TEXTULARINA. — Textularia, Defrance,

PI. 23. figs. 47, 52 (Vuhulina, d'Orb., PI.

23. fig. 49; Bigenerina, d'Orb., PL 23.

fig. 50; Venilina, G umbel; Pavonina

FORAMINIFERA.

[ 333 ]

FORAMINIFERA.

d'Orb. ; Spiroplecta, Ehrenberg ; Caneolina,
d'Orb.) ; Verneuilina, d'Orb. (Gaudryina,
d'Orb., PI. 23. fig. 48 ; Heterostomella, Rss. ;
Chrysalidina, d'Orb. ; Tritaxia, Rss.) ; Val-
vulina, d'Orb., PL 23. fig. 20 (davulma,
d'Orb., PL 23. fig. 51).

b. BULIMINIXA. — BuKmma. d'Orb., PL
23. fig. 46 ( Virgulina, d'Orb. ; Bolivina,
d'Orb. ; £ifarma,P. & J.j Eobertina, d'Orb. ;
Pleurostomella, Reuss).

c. CASSIDULININA. — Cassidulina, d'Orb.,
PL 23. fig. 45 j Ehreribergina, Reuss.

GROUP V. Test calcareous, finely perforate.
Fam. 7. Chilostomellidae.

Chilostomella, Reuss; Allomorphina,

Reuss j Ellipsoidina, Seguenza.

Fam. 8. Lagenidae.

«. LAGEXINA. — Lagena, Walker and
Jacob, PL 23. figs. 22, 24-27 (Entosolenia,
Ehr., PL 23. fig. 23 ; Fissurina, Reuss) ;
Ramulina, Jones. Nodosarina : — Nodosaria,
Lam., PL 23. fig. 28 (Glandulina, d'Orb.;
Dentalina, d'Orb., PL 23. fig. 33; Lingu-
lina, d'Orb.) ; Orthocerma, d'Orb., =

, .

fio-. 35 (Rimulina, d'Orb.); Marginulina,
d'Orb., PL 23. figs. 30-32; Cristellaria,

., .

Lam., PL 23. figs. 34, 37 (Planularia,
Defr.) ; Flabellina, d'Orb., PL 23. fig. 38.

b. POLYMORPHININA. — Polymorpkina,
d'Orb., PL 23. figs. 40-43 (Dimorphina,
d'Orb.) ; Uvigerina, d'Orb., PL 23. fig. 44
(Saffrina, d'Orb.).

GROUP VI. Test calcareous, generally with
coarse perforations; without canal-
system.

Fam. 9. Globigerinidse.

Globigerina, d'Orb., PL 24. figs. 2, 3 (Or-
bulina, d'Orb., PL 24. fig. 1); Pullenia,
Parker and Jones ; Spheeroidina, d'Orb.
(PL 24. fig. 4) ; Candeina, d'Orb.

GROUP YII. Test calcareous, coarsely per-
forate ; some with double chamber-
walls and interseptal canals.

Fam. 10. Rotalidde.

Spirillina, Ehrenb. (PL 24. fig. 5) ;
tellina, Williamson (PL 24. fig. 8); Du
Una, P. & J. (PL 24. fig. 7); Planorbu

Pa-

, ^ 'Discor-

„.,_, . v D- , , Planorbulina,

d'Orb., PL 24. figs. 6, 10, 12 (Tmncatulina,

d'Orb., PL 24.fig. 9; AnomalinafiOrb.) ; Ru-
pertia, Wallich ; Carpenteria, Gray ; Poly-
trema, Risso ; Tinoporus, Carpenter ( = Gyp-
sina, Carter) ; Cymbalopora, von Hagenow
(PL 24. fig. 17) ; Thalamopora, Rss. ; Put-
vinulina, P. & J. (PL 24. figs. 11, 16) ; Rotalia,
Lamarck (PL 24. figs. 13, 14) ; Calcarina,
d'Orb.

GROUP VI II. Test calcareous, very finely
tubulated ; all the higher forms with a
system of interseptal canals.

Fam. 11. Nummulitidse.

a. POLYSTOMELLINA. — Nonioninttj d'Orb.
(PL 24. fig. 18) ; Polystomella, Lam. (PL 23.
fig. 55, PL 24. tigs. 19, 20).

b. NUMMULITINA. — Archtsdiscus, Brady ;
Amphistegina, d'Orb. (PL 24. fig. 28) ; Fu-
sulina, Fischer (PL 24. fig. 15); Eozoon,
Dawson ; Cycloclypetis, Carpenter ; Hete-
rostegina, d'Orb. ; Operculina, d'Orb. (PL
24. figs. 23-26); Ntimmulites)~La>m., PL 24.
figs. 21, 22 (Assilina, d'Orb.).

Unplaced groups : —

GROUP IX. Testamcebiformia, Carter.
Lobose forms.

a. Test calcareous. — Holocladia and Cys-
teodictyina, Carter.

b. Test chitinous. — Cerastestina, Carter.

GROUP X. Syringosphaeridae, Duncan. Test
calcareous, with radiating groups of
tubules.
Syringosphceria and Stoliczkaria, Duncan.

GROUP XI. Receptaculitidae, Giimbel. Test
calcareous, consisting of an inner and
an outer floor of plates, connected by
the tubes of an anastomosing canal-
system.
Receptaculites, Defr. ; Ischadites, Konig ;

Tetragonis, Eichwald ; Sphceronites, Hisin-

ger ; Sphcerospongia, Salter.

BIBL. D'Orbigny,D^. Sc. Nat.1826, vii.;
Mem. Soc. Geol. France, iv. ; Diet. d>HisL
Nat. 1845, v. ; Foram. foss. Vien. 1846 ;
Ehrenb. Mikrog. 1854 ; id. Abh. Ak. Berlin.
1838, 1839, 1841, 1847, &c. ; Weaver, Ann.
N. H. 1841, vii. 296, 374; Dujardin, Ann.
Sc. Nat. 1835, iv. & v. ; Clark, Ann. N. H.
1849, iii. 388, 1850, v. 161; Williamson,
Tr. Micr. Soc. ii., and Recent Foraminif.
(Ray Soc.) ; Carpenter, Tr. Geol. Soc. 1849 ;
Microscope ; Phil. Tr. 1856, 59, 60, 69;

FORDA.

[ 334 ]

FRAGILARIA.

Introd. Foram.-j Center, Ann. N. H. 1852,
x., 1853, xi., 1854, xiv., &c. ; Schultze,
Organism. Poll/thai. ; Midler's Archiv, 1856
(Q. J. Micr. Soc. v. 220) ; Wiegmann's
Archiv, 1860 (Ann. N. If. ser. 3, vii. 306) ;
Parker, Jones, and Brady, Ann. N. H. 2.
xix. j 3. in., iv., vi., viii., xi., xii., xv., xvi. ;
4. iv., vi., viii., ix., x. ; Q. J. Geol. Soc. xvi.
292, 452 j xxviii. 103 ; Phil. Trans. 1865 j
TV. Linn. Soc. 1864 and 1870; Monogr.
Crag For. (Pal. Soc.} 1866 ; lieuss, Vent.
Bohm. Kreid. 1845-46 ; Raiding . AbhandL
iv. ; Denksch. Akad. Wien, i., vii., xxiii.,
xxv. ; 8itz. Ak. Wien, passim ; Zeitsch. dent.
geoL Ges. iii., vii., &c. ; Giimbel, Abhandl.
bai/r. Ak. x. «fec. ; also the memoirs of Sol-
dani, R6;ner, Von Hagonow, Philippi,
lieuss, Czjzek, Alth, Bornemann, Egger,
Neugeboren, Karrer, &c.

Since 1875 the following have added to
the bibliography of the subject : —

A. M. Norman, J. D. Siddall, J. II. Carter,
W. J. Sollas, J. F. Blake, E. Vanden Broeck,
Joseph Wright, H. B. Brady, A. W. Waters,
Ph. de la Harpe, W. K. Parker, T. R. Jones,
G. Stache, F. Karrer, C. W. Giimbel, J. W.
Dawson, 0. Schwager, M. von Hantkeu,
G. Steinmann, G. 0. Wallich,P. M. Duncan,
G. Terrigi, C. Mobius, J. Seguenza, &c.

FOR'DA, Heyden. See APHID.*:, p. 63.

FORFIC'ULA, Linn. F. auricularis is
the common earwig.

FORMIC ACID, or acid of ants.— This
acid occurs in ants, especially the red ant,
Formica rufa ; in the stinging hairs of some
insects, as of the procession - caterpillar
(Eombi/xprocessionea)', and in the poisonous
secretion of the stings of insects ; perhaps
also in the stinging organs of the Acalephae
and Polypes. In the higher animals it is a
frequent product of the oxidation of organic
substances, and is also found in the juice of
flesh, in the urine, in vomited liquids, and
in the blood ; also in the stinging hairs of
the nettle &c.

FOSSIL INFUSORIA. — The fossil
valves of the Diatomaceae were formerly so
called. See DIATOMACEAE.

FOSSIL WOOD.— This occurs in very
different conditions : — as, for example, con-
verted into lignite, and the modifications
of coal j or with the vegetable substance
almost entirely removed and replaced by
silex, preserving all the organic forms of
the tissues. The mode of examining and
mounting COAL, &c., is given under that
article. Silicified woods which have been
completely infiltrated and solidified require

to be cut into thin sections and polished by
the lapidary ; the friable kinds, where the
infiltration has merely filled the cavities of
the cells and vessels, may be split with a
knife and mounted in balsam. Examples
are given in PL 25. figs. 29-33. PI. 48.
fig. 32, exhibits concretions of silica imi-
tating structure. The stems of Palms and
Dicotyledonous trees are met with com-
pletely converted into siliceous blocks, sec-
tions of which exhibit all the minutiae of
the structure.

FOSSOMBRO'NIA, Raddi.— A genus of
Pellieae (Hepaticae), nearly allied in the
character of its vegetative structure to the
Jungermannieae, having large, squarish,
irregularly waved leaves. The stout stems
are procumbent, and set with purple radi-
cles all along the underside. The fruit-
stalk arises from the underside of the stem,
and turns back ; the perichaete is very large ;
and the capsule bursts irregularly into four
slender erose valves. F.pusilla is the Jun-
f/ertnanttia pusilla of the British Flora;
found chiefly on clay banks.

BIBL. Hook. Brit. Jungerm. pi. 60, Brit.
Flor. ii. pt. 2. 117 j Endlicher, Gen. Plant.
suppl. i. no. 472-7.

FOVIL'LA.— The name applied to the
liquid granular matter filling the pollen-
cell and passing into the pollen-tube of
Flowering Plants. The minute granules,
which are of various but altogether indefi-
nite sizes, exhibit an active quivering mo-
tion— the molecular motion, as it is called
— which is displayed in the same way by
all finely-divided solid substances, living or
dead, and is apparently dependent on purely
physical causes. They appear to consist of
starch-grains, minute globules of oil, and
granules of protoplasm probably composed
of proteine compounds. These granules are
exceedingly transparent in many kinds of
pollen when fresh^from their refractiug-
power being nearly equal to that of the
fluid surrounding them. They may be made
visible by adding water.

FRAGILA'RIA, Lyngb.— A genus of
Diatomaceae (Cohort Fragilarieae).

Char. Frustules (in front view) linear,
symmetrical, united into straight or twisted
ffat filaments ; valves lanceolate, oblong or
linear.

Differs from Diatoma in the filaments not
becoming separated into zigzag chains.
Transverse striae only visible under oblique
or "stopped" illumination.

Kutzing enumerates sixteen species, of

FREDERICELLA.

[ 335 ]

FRONDICULARIA.

which ten are doubtful. Rabenhorst ad-
mits 9 species, with numerous varieties.

F. capucina, K. (F. rhabdosoma, E., PI. 16.
fig. 33). Frustules linear in front view ;
valves narrowly and acutely lanceolate;
breadth of filament 1-700". Freshwater.
Common in pools, &c.

/3. Valves attenuate towards the obtuse
ends.

F. virescens, Ralfs (F. pectinalis, Ehr.).
Frustules in front view linear, rectangular
or cuneate ; valves obtuse at the contracted
and produced ends. Freshwater. Endo-
chronie green.

/3. Valves cohering by the angles only.
F. striatula. Valves linear, narrowed
towards the very obtuse ends. Marine.

BIBL. Kiitzin'g, Bacill. 45; id. Sp. Alg.
14; Ralfs, Ann. N. H. 1843, xii. 106;
Smith, Brit. Diat. ii. 21 : Rabenhorst. Flor.
Alg. i. 118.

FREDERICEL'LA, Gervais.— A genus
of Polyzoa, of the order Hippocrepia, and
fiunily PlumatellidsB.

Char. Polypidom fixed, coriaceous, tubu-
lar, branched ; polypes protruding from the
ends of the branches ; tentacular disk nearly
circular; tentacles about twenty-four, ar-
ranged on the margin of the disk in a single
series, and invested at their origin by a
membrane. Freshwater.

F. sultana. Polype-cells erect, cylindrical.
Height of zoary about 2" ; tufted, shrub-
by; stem dichotomously branched. Eggs
bean-shaped, smooth.

BIBL. Allman, Freshw. Polyzoa (Ray
Soc.}, 110 ; Johnston, Br. Zooph. 405.

FREI'A, 01. & L.— A genus of Infusoria,
of the family Bursarina.

Char. Those of Stentor, with the buccal
spire borne by an anterior membranous bi-
lobed expansion.
3 species : marine.
F. elegans (PI. 52. fig. 1.).
BIBL. Clap, and Lachm. Infus. 217; St.
Wright, Qu. Mic. Jn. 1862, 217.
FREY'A. See FBEIA.
FROG. — The common frog (Rana tempo-
raria) affords a means of studying several
interesting points of structure. Thus, by
gently scraping the back of the roof of the
mouth with the handle of a scalpel, ciliated
epithelium (PL 49. fig. 13) may be obtained,
and the ciliary movement studied. The
circulation in the web of the foot, and the
phenomena of inflammation may be ob-
served, by enclosing a frog in a wet bag,
leaving one leg projecting. The bag con-

taining the frog may then be placed upon a
plate of wood, with a circular aperture at
one end, over which the foot is to be ex-
tended by tying the toes with silk or cotton
threads to little tacks or nails driven into
the wooden plate. Metal " frog-plates "
are sold for the purpose. Sections of the
kidney of the frog, made with a Valentin's
knife, will show the ciliated epithelium of
the necks of the urinary tubules. The
circulation of the blood in the lungs and
the mesentery may be examined ; but the
animal should be rendered insensible by
chloroform before the experiment.

The ova of the frog (frogs' spawn) have
formed the subject of some of our most
interesting experiments on impregnation
and development. The larvse (tadpoles)
exhibit well the circulation in the gills,
tail, and more transparent parts, and afford
easily obtained materials for the study of
the development of the tissues. The chorda
dorsalis is well seen in a young tadpole.
The frog and tadpole, however, are inferior
in most respects to the Triton and its larvse
for exhibiting these phenomena.

The injected organs of the frog afford
most interesting and beautiful preparations,
especially the lungs, kidneys, skin, tongue,
and web of the foot. The injection should
be thrown in at the heart, and the slightest
possible force used. The simplest method
of killing a frog without injury, is to
immerse and retain it in warm water.

The muscles of the frog often contain
a nematoid parasite (Myoryktes Weiss-
manni).

FRONDICULA'RIA, Defr.— This pseu-
do-genus comprises flat stichostegian Nodo-
sarina, which have geniculate or chevron
chambers. They are the extremely com-
pressed and dilated forms of the group,
having the quasi-genus Lingulina to connect
them with the cylindrical Nodosarice. In
Frondicularia the shell is equilateral ; nar-
row-oblong, rhomboidal, or ovate; greatly
compressed; chambers in a straight row,
depressed, each forming two sides of a tri-
angle, with the angle sometimes prolonged ;
septal lines often raised as ridges ; inter-
mediate spaces sometimes striate; first
chamber oval ; aperture round, on the upper
angle.

Recent in the Atlantic. Fossil in the
Tertiaries of Italy, Spain, and West Indies ;
and abundant in the Chalk, Gault, Lias, and
other fossil clays. Fr. spathulata (PL 23.
fig. 39) shows the early portion of a speci-

FRONTONIA.

[ 336 ]

FUCACE.E.

men from the Chalk, closely allied to the
typical Fr. complanata, Defr.

BIBL. D'Orbigny, For. Foss. 67; Wil-
liamson, Itec. For. 23 ; Morris, Br. Foss. 35 ;
Reuss, Bohm. Kreid. ; Carpenter, Introd.
For. 160, 164.

FRONTO'NIA, Ehr.— A genus of Infu-
soria, of the family Bursarina (Cl. & L.).

Char. Resembles Ophryoglena, except in
the absence of the watch-glass organ.

Most of the species of Dujardin's genus
Panophrys belong here.

F. leucas (Bursaria L, Ehr.). Parenchyma
armed with trichocysts ; buccal fossa oval,
pointed behind j a single contractile vesicle.
Freshwater.

BIBL. Ehrenfeerg, Inf. 329; Clap, and
Lachm. In/us. 259.

FRULLA'NIA,Raddi.— A genus of Jun-
germannieae (Hepaticae), containing three
British species, the Jungermannia Hutchin-
SICB, dilatata, and Tamarisci of Hooker's
British Flora. F. dilatata is very common,
creeping on the bark of trees, its dark brown
dry foliage appearing like minute spreading

Fig. 251.

Frullania Tamarisci.

Portion of a stem, with branches bearing the perichsetes
from which the sporanges emerge.

Magn. 5 diams.

blotches; the almost sessile capsules are
somewhat inconspicuous, but are distin-
guished by their whitish colour. The valves
of the capsule and the elaters afford beauti-
ful microscopic objects, illustrative of the
spiral structures in cells. F. Tamarisci
(fig. 251) has longer and more regularly pin-
nate stems, forming large lax tufts on the
ground and low bushes, chiefly in Subalpine
countries.

BIBL. Hook. Brit. Jungerman. pis. 1, 5, 6;

Brit. Flora, ii. pt. 1. 128 ; Endlicher, Gen.
Plant. Suppl. i. No. 472-10.

FRUSTU'LIA, Ag.— A genus of Diato-
macese.

Char. Frustules naviculoid, free or irre-
gularly scattered through an amorphous
gelatinous mass ; valves elliptic-lanceolate,
without central and terminal nodules ; lon-
gitudinal line interrupted in the middle.
Freshwater.

F. salina, Ehr. Frustules in front view
very narrowly linear, rounded at the ends ;
valves suddenly acute at the ends ; trans-
verse stria) evident; gelatinous envelope
continuous; length of frustules 1-2200 to
1-864". Found in a saline spring.

This organism is of particular interest,
as having formed the subject of Schmidt's
ultimate analysis, in which he determined
the presence of cellulose. (DIATOMACEJE,
p. 249.)

F. membranaceay nobis (PI. 50. fig. 6).
Frustules in front view linear, very slightly
narrowed towards the ends ; valves lanceo-
late, constricted near the obtuse ends;
length of frustules 1-1250".

Found abundantly forming a thin stratum
or film upon the sides of a glass jar con-
taining water-plants.

F. saxonica, Rab. (PL 19. fig. 17). Frus-
tules in front view linear, rounded at the
ends ; valves elliptical, somewhat acute.

Forms dirty olive-brown, gelatinous, tre-
mulous masses, contained in small pits in
rocks.

This is sometimes used as a test-object.
It is regarded by Dallinger and others as
the same as Navicula rhomboides and crassi-
nervis.

Rabenhorst describes 5 species ; one
fossil.

BIBL. Ehrenb. In/us. 232 ; Kiitzing,
Bacitt. 109 ; id. Sp. Alg. 96 ; Rabenhorst,
Fl. Alg. i. 227 ; Hickie, M. M. Jn. 1876,
xv. 122 : Stodder, ibid. 253 : Dallinger, ibid.
1877, xvii. 1, 173.

FUCA'CE^E.— A family of Fucoideaa.
Olive-coloured inarticulate sea-weeds, whose
reproductive organs are borne in stalked sacs
upon the walls of spherical cavities excavated
in the substance of the frond. Fructification,
sporanges or spore-sacs and antherid'ia. The
spores of Fucus divide into two, four, or
eight within the sac ; those of the other
genera remain undivided. The antheridia
are filled with spermatozoids or anthero-
zoids, which in FUGUS have been seen to
fertilize the spores. See Fucus.

FUCOIDE^E.

British Genera.
Air-vessels stalked.

[ 337 1

FUCOIDE^E.

Sargassum. Branches bearing ribbed
leaves ; air-vessels simple.

Halidrys. Frond linear, pinnate, leafless ;
air-vessels divided into several cells by
transverse partitions.

** Air-vessels immersed in the substance of
the frond or absent.

Cystoseira, Root scutate. Frond much
branched, bushy. Receptacles cellular.

Pycnophycus. Root branching. Frond
cylindrical. Receptacles cellular.

Fucus. Root scutate. Frond dichotomous.
Receptacles filled with mucus, traversed by
jointed threads.

HimantJialia. Root scutate. Frond cup-
shaped. Receptacles (frond-like) very long,
strap-shaped, dichotomously branched.

FtJCOrDEJB, or MELANOSPORE.E.
— An order of Algae, deriving their ordinary
name from the Fucus or Wrack, one of the
most common genera of the family. They

E resent many remarkable points of difference
:om the red sea-weeds in their higher forms,
while the lowest forms approach the simpler
genera of that order and the higher forms of
the Confervoideee. The Fucoids are exclu-
sively marine, and are at once distinguished
by their olive or dark-brown colour; and
although some of the larger kinds grow in
deep water, the majority are met with on
rocks between high- and low- water mark,
where they are exposed to the atmosphere
at each efflux of the sea : those which are
occasionally drawn up from deep water prove
that this exposure is necessary for healthy
growth, by their wreak structure and the
absence of fructification. Some of them
are also provided with air-bladders, which
maintain them floating or erect and with at
least their upper lobes little beneath the
surface of the water. These air-bladders
are very well seen in our common Bladder-
wrack (Fucus vesiculosus, fig. 252) ; and still
more so in the celebrated Gulf-weed (Sar-
gassum bacciferuni), where the stalked berry-
like bladders are the most striking feature
of the plant.

All the larger kinds grow on rocks, to
which they are attached by a root-like
structure, of somewhat conical form, cleav-
ing, like the ' sucker' with which school-boys
lift stones, to the rock ; in many this cone
is solid, and composed of tough cellular
tissue ; in others, especially the Laminaria-

ceae, it is composed of a number of stout,
super] acent, branched cords, growing out of
the frond one above another, and attaching
themselves to the rock, like the roots of a
Tree-fern or a Palm. Some (Pycnophycus)
spring from a creeping stem-like portion,
spreading in a netted mass over the rocks, —
while many of the smaller are parasitical
or, more properly, epiphytic, growing on the
fronds of the larger kinds, to which they
attach themselves by minute ( sucker '-like
disks. Some appear to be true parasites
(Elachistece and Myrionemata). Several are
of minute size, but very few strictly micro-
scopic. Almost all present three regions,
resembling respectively the root, stem, and
leaf or leaves of the higher plants, although
they are not ordinarily regarded as the
morphological analogues of them. In a few
cases the frond is a shapeless mass or crust,
lying close to the surface of the rocks.
None become calcified like the Corallines.

The fructification of these plants is still in
a somewhat obscure condition as regards the
order in general; for great apparent diversi-
ties occur in the physiological phenomena
presented by what at first appear like iden-
tical structures. We have here, as in the
Floridea, three distinct form s of reproductive
structure, known respectively as : — 1, zoo-
spores ; 2, spores ; and 3, spermatozoids.

1. The zoospores are the reproductive bo-
dies most frequently met with ; and in the
lower forms the arrangements are not very
different from those in the filamentous Con-
fervoids. In ECTOCABPUS, where the frond
is composed of jointed cellular filaments,
the cells at the ends of the branches, or
other articulations, become enlarged and
filled with granular matter which is ulti-
mately converted into zoospores. These en-
larged cells are called by Thuret sporanges,
and are commonly described as spores in
algological works ; but they burst and dis-
charge the numerous microscopic zoospores,
which are pear-shaped, with a clear, beak-
like, narrow end, of olive colour, and have
two cilia, not arising from the beak, but
from a reddish point on the coloured por-
tion ; one cilium is longer than the other,
and directed forwards ; the other is short,
and trails behind like a kind of rudder.
Their movements are very active ; and they
seek the light. When they germinate, they
become immovable and spherical, acquire
a membranous coat, and emit a tubular pro-
longation, which soon becomes divided by
cross septa, and is developed into a new

FUCOIDE^E.

[ 338 ]

FUCOIDE.E.

frond. In some cases the sporanges are
multilocular (trichosporanffes), consisting- of
very slender, and usually rather short, j ointed
filaments, in each joint (cell) of which a
single zoospore is produced. These occur in
considerable numDer, occupying the same
place ^as the unilocular kind, which they
sometimes accompany ; and the two forms
appear to pass one into the other. The
zoospores are perfectly similar, except that
those produced singly in the filaments are
not so large as those developed in large
numbers in the large, ovate, unilocular
sporanges.

The two forms of sporange producing
zoospores have been found in the Myrione-
maceaejChordariaceae, Sporochnacese, Punc-
tariaceae, and Dictyosiphonacese ; in Chorda
lomentaria only the multilocular, and in the
other LaminariaceaB only the unilocular,
have been seen at present.

The Cutleriaceae present the remarkable
phenomenon of the occurrence of sporanges
containing zoospores together with anthe-
ridia analogous to those of the FUCACE^:.
(See CUTLERIA.)

Those Fucoideae in which the repro-
duction is effected by zoospores only, form
Thuret's group of Phseosporese.

2. The spores occur in the Dictyotaceae
and the Fucacese, as large granular bodies
of ovate form, enclosed in a sporange or
oogonium, and clothed besides by a gela-
tinous coat called the epispore ; these large
spores are always devoid of power of motion.
In some cases they are simple reproductive
spores ; in others they subdivide, after es-
caping from the perispore, into two, four, or
eight sporules, each capable of germination.
(See Fucus, and figs. 253, 256.) In the
Dictyotaceae these spores are collected into
definite groups (sort) on the surface of the
frond. In the Fucaceae the spores are
found in spherical cavities immersed in the
substance of the frond, sometimes occurring
in all parts, sometimes collected in special
regions. These cavities communicate with
the external surface by pores, and are usually
perceptible from the swollen slimy appear-
ance where they open. Where no general
receptacles exist, the little spherical cham-
bers are excavated in the frond; where
these do occur, as in Fucus, the spherical
chambers are attached to the inside of their
walls, one beneath each external pore.
These chambers, called by some scapMdia,
by others conceptacles, contain spores or
antheridia, or both. The spores occur in

sacs consisting of a cell (perispore) springing
from the wall of the chamber. (See
Fucus.)

3. Spermatozoids have been met with, as
well as zoospores, in the Cutleriaceae. The
spermatozoids or antherozoids exactly resem-
ble those of Halidrys and Fycnophycus,
described below.

In Dictyota the spermatozoids occur on
separate plants, in antheridia grouped in
sori like the spore-fruit.

In the Fucaceae the spermatozoids or
antherozoids occur with the spores above
described. In Fucus canalicidatus (Pelvetia,
Dene, and Thuret) and F.platy carpus (Thu-
ret) the antheridia are found, in company
with the snores, in the conceptacles ; in the
other species of Fucus the two kinds of
organs are never met with together in the
same conceptacle; in Himanthalia lorea
they are on distinct plants, in Halidrys
siliquosa intermingled, and in Pycnophycus
tuberculatus in the same chamber but not
mixed. The antheridia of these plants
consist of transparent ovoid sacs, inserted
in great number on the branched hairs
(parancmata) (fig. 254) clothing the inside
of the fruit-chambers or scaphidia. In some
genera they have a double coat, in others
only one ; when two exist, the inner is
expelled as a sac on the rupture of the an-
theridium ; when only one exists, the sper-
matozoids are expelled individually and
freely from the single coat, which always
remains attached upon its support. The
spermatozoids or antherozoids found in
these sacs are little hyaline globules, each
enclosing a granule of grey colour in Fucus
canaliculatus, red-orange in all other species
of Fucus and other genera. They bear two
locomotive cilia, very slender, and of unequal
length. The form of the corpuscles and the
arrangement of the cilia differ in different
genera. In all the species of Fucns the
spermatozoids are of the shape of little
bottles, the neck of which, always foremost
in the movement, bears the shortest cilium ;
the longer arises from the coloured granule,
and trails behind. In Halidrys, Pycnbphycv*,
and Cystoseira, the corpuscle is oval or
spherical in one dimension, and compressed,
sometimes a little convex, in the other;
both the cilia are inserted on the red granule,
and during the locomotion the corpuscle
turns upon its own axis, with the longer
cilium in advance, vibrating with rapidity,
while the shorter is motionless. In H\ma/&
thalia the antheridia have a double coat; the

FUCOIDEJ3.

FUCUS.

form of the antherozoids is not clearly made
out. The antherozoids of the Fucaceae have
been shown by Thuret, their discoverer, to
be analogous to the spermatozoids of the
higher Cryptogamia, and to perform a ferti-
lizing function — not to reproduce the plant
like the zoospores of the other families ;
and the multiplication appears to be effected
solely by the large olive-coloured spores.
(See FUCACEJE.)

Synopsis of the Families.

FUCACEJE. Frond leathery or mem-
branous, cellular. Fructification : spores and
antheridia contained together or separately
in spherical cavities imbedded in the frond.

DICTYOTACEJE. Frond cellular, flat,
compact. Fructification : spores, antheridia
(and tetraspores?) arranged in definite spots
or lines (sori) on the surface.

CUTLEBIACEJE. Frond cellular, com-
pact, ribless. Fructification : dot-like scat-
tered collections of "sporanges divided into
eight compartments; and antheridia con-
sisting of chambered filaments in groups of
curved j ointed hairs.

ECTOCABPACE J3. Frond filiform, jointed.
Fructification: unilocular sporanges, ovate
sacs developed at the ends or intermediate
ioints of the filaments; and multilocular
'sporanges, consisting of minute jointed
filaments found in similar situations. An-
theridia with spermatozoids have been
found in Sphacelaria.

LAMINABIACE^E. Frond leathery or gela-
tinous, cellular. Fructification: unilocular
sporanges in indefinite cloud-like patches,
or covering the whole surface of the frond ;
or multilocular sporanges clothing the whole
surface of the frond like an epidermis.

DICTYOSIPHONACE^E. Frond cylindrical,
branched, of filamentous structure. Fruc-
tification : ovoid sporanges imbedded length-
ways in the substance of the frond, opening
bv a pore on tne surface.

PUNCTABIACE^:. Frond cylindrical or
flat, unbranched, cellular. Fructification:
ovate sporanges in groups on the surface,
intermixed with clavate filaments (para-
physes).

SPOBOCHNACEJE. Frond leathery or mem-
branous, cellular, branched. Fructification ;
unilocular or multilocular sporanges attached
to external jointed filaments, free or collect-
ed in knob-like masses.

CHOBDABIACE^. Frond cartilaginous or
gelatinous, composed of horizontal and ver-
tical j ointed filaments interlaced. Fructifi-

cation : unilocular sporanges springing from
the base of the vertical filaments forming
the epidermis of the frond; and multilocular
sporanges developed later from the filaments
surrounding the former.

MYBIONEMACE^:. Frond tuber-shaped,
crustaceous, or spreading as a crust, of fila-
mentous structure. Fructification : unilocular
and multilocular sporanges attached to the
superficial filaments, and concealed among
them.

BIBL. See that of the Families.

FU'CUS, Linn. — A genus of Fucaceae
(Fucoid Algae), including some of the com-
monest and most abundant of our olive-
coloured sea-weeds, growing upon rocks
and stones between tide-marks, their large
fronds waving in the water at high tide,
and lying matted together over the rocks
when the tide is out; continually cast
ashore in quantities after rough weather.
F. vesiculosus, the common bladder-wrack, ia
familiar to every one who has visited a sea-
coast. Decaisne and Thuret divide the
genus into three: Pelvetia(F.canaliculatus)t
Ozothallia (F. nodosus} , and Fucus proper,
including F. serratus, vesiculosus, and cera-
noides.

In F. nodosus and jP. Mackaii the recep-
tacles are lateral and stalked ; but in all the
rest they are terminal and continuous with
the frond (fig. 252), forming oval thickened

Fig. 252.

End of a branch of F. vesieulosus, bearing two terminal

receptacles.
Half the nat. size.

clubs, on which, by the naked eye, may be
distinguished a number of spots or pores.
These are the orifices of the conceptacles,
which are globular cases immersed in the
substance of the receptacle, and communi-
cating with the outer surface by a pore (fig.
253). The central portion of the receptacle

z2

FUCUS.

[ 340 ]

FUCUS.

is filled up with a delicate network of jointed
filaments surrounded by a gelatinous sub-
stance, this medullary structure forming a
bond of union between the numerous con-
ceptacles. The internal wall of the con-
ceptacles is lined with a dense mass of de-
licate jointed filaments (fig. 253) standing
vertically (paraphyses), among which ap-
pear the stalked spore-sacs, alone in the
dioecious and monoecious forms, mixed with

Section of a conceptacle of F. canaliculatus, containing

eporanges, antheridia, and paraphyses.

Magnified 40 diameters.

antheridia in the hermaphrodite. The an-
theridia occur alone in similar conceptacles
in the monoecious and dioecious forms. F.
canaliculatus is hermaphrodite (like Pycno-
phycus tulerculatus, which, however, has
antheridia only at the upper part of the
conceptacle, near the pore, spore-sacs at the
lower part) ; in F. serratus, ceranoides, vesi-
culosus, and nodosus the male and female
conceptacles occur usually on distinct plants ;
but both kinds sometimes occur on F. nodo-
sus. The male and female individuals of
the dioecious species may often be distin-
guished, when mature, by the yellowish
colour the antheridia give to the recep-
tacles ; and if these are exposed for a short
time to the air, the antheridia are expelled
in masses through the pores of the con-
ceptacles, and form little orange -coloured
papillae. The female plants under similar
circumstances exhibit olive-coloured papillae
at the mouths of the pores, consisting of
masses of spores.

The sporanges or spore-sacs consist of
ovate sacs, stalked, on the walls of the con-
ceptacle (fig. 253) ; they have a double
membrane — an outer, the sporange or peri-
spore, and an inner, the epispore : these are
undistinguishable until the spores escape ;
but then the epispore becomes evident as an
inner sac. The epispore encloses at first a
mass of olive-coloured cell-contents ; in F.
canaliculatus (Pelvetia) this divides into two

spores, in F. nodosus (Ozothallid) into four,
and in F. serratus, vesiculosus, and the other
Fuci proper, into eight, by segmentation.
When mature, the sporange bursts at the
apex; the epispore enclosing the spores is
expelled, and makes its way towards the
pore of the conceptacle, and falls into the
water, where it undergoes the following
modifications. Taking F. vesiculostis as an
example, the expelled epispore encloses
eight spores, forming what Thuret calls an
octospore. This swells ; and the spores be-
come rounded, separating from each other ;
and the upper part of the epispore begins to
dissolve. The spores become removed from
the lower part of the epispore (marked by
the impression of the stalk of the sporange) ;
and it then becomes evident that they are
enclosed in a third membrane, which is at-
tached to the epispore in the centre of its
base, so that as the spores emerge from the
dissolving summit of the epispore the in-
ternal membrane becomes stretched upward,
until it finally bursts and sets the spores free.
These changes of the octospore are generally
passed through in about an hour, sometimes
much more rapidly.

The antJiendia consist of minute ovate
sacs, attached in great numbers to hair-like
filaments growing from the internal surface
of the conceptacle (fig. 254). When young,

Fig. 254. Fig. 255.

Fig. 254. A branched cell of F. nodosus, bearing a per-
fect and an imperfect antheridium. Magn. 200 diams.

Fig. 255. Sac of an antheridium of F. serratus, nearly
empty. Magn. 400 diams.

they are filled with colourless granular
matter ; but subsequently this becomes con-
densed into little corpuscles (spermatozoids
or antherozoids), forming a greyish mass
dotted with orange points. The sac is
double ; and the internal one is expelled
from the outer like the epispore from the
sporange, and finds its way out from the
pore of the conceptacle. The spermatozoids
which fill up the central part begin to move
actively : and the sac soon bursts at one or
both ends to discharge them. The sperma-
tozoids (fig. 255) are excessively minute,
transparent bodies, scarcely 1-5000" long,
enclosing a granule of an orange-colour in

FUCUS.

[ 341 ]

FUNAEIACE^E.

most spores, but greyish in F. canaliculatus.
The sperrnatozoids have two cilia, of un-
equal length, one directed forwards, the
other backwards ; the form of the sperma-
tozoids and the direction of the cilia vary
in different species, — the one directed for-
ward usually moving with great rapidity,
and producing locomotion, while the other
trails behind like a rudder.

The most interesting and important point
connected with the genus Fucus is the
process of fecundation.

When a drop of sea-water containing
active spermatozoids, is added to a slide
upon which the free spores above described
have been previously placed, the whole
operation of the fertilization may be traced
under the microscope. The spermatozoids
attach themselves in great numbers to the
spores, and by the motion of the cilia com-
municate to them a rotatory movement,
often very rapid. The Held of the micro-
scope becomes covered with these large
brownish spheres bristling with spermato-
zoids, and rolling in all directions among
the crowd of those still unattached. After
about half an hour, the movement of the
spores ceases ; the spermatozoids move for
some time longer. In a few minutes after
the contact of the spermatozoids, such fer-
tilized spores will be found coated with a
membrane, the presence of which is readily
made out by placing the spore in syrup,
which causes the granular contents to con-
tract and shrink away from the envelope,
which, moreover, may be coloured blue by
sulphuric acid and iodine. The spore next
begins to enlarge and grow by cell-division,
one end becoming elongated into a trans-
parent filament like a radicle (fig. 256) ;
several more of these are afterwards formed

Fig. 256.

Spores of F. serratus in various stages of germination.
Magnified 100 diameters.

as the upper part grows ; and they become
organs of attachment by which the young
frond is fixed to a stone or other support.

The above description corresponds in all
essentials to the process as it occurs in the
other species. The spores of F. vesiculosus
have been fertilized with spermatozoids of
F. serratus by Thuret ; but no other expe-
riments of hybridation were successful.

One or two other points deserve notice.
The orange spot of the spermatozoids is co-
loured blue by sulphuric acid (like CHLORO-
PHYLL). Sugar and sulphuric acid colour
the spermatozoids red (PROTEINE). The
membrane of the sporange (perispore) is
coloured blue by sulphuric acid and iodine
(CELLULOSE) ; but this is not the case with
the epispore nor the internal membrane,
even after treatment with caustic potash.
In F. canaliculatus^ however, there is a la-
minated coat immediately surrounding the
spores, which when placed in sea-water
separate, while the coat swells and forms a
kind of gelatinous envelope, which appears
as if covered with cilia ; these pseudo-cilia
seem to be analogous to the similar appear-
ances in the gelatinous sheath of DESHI-
DIACEJE and other CONFERVOIDS.

The months from December to March are
the most favourable for observing the above
phenomena. No covering glass must be
used on the slide, unless prevented by a thin
glass support from pressing on the spores
and deforming them. A power of 150 to
200 diameters suffices for most of the ob-
servations,— for the spermatozoids and the
actual fecundation, a power of 300. Sea-
water must always be used. The germina-
tion of the spores may be observed by placing
them on glass slides moistened with sea-
water, and keeping them under a bell-glass
standing in a dish containing sand moistened
with sea-water.

BIBL. Harvey, Mar. Alg. 18, pi. 1 D ;
Phyc. Brit. pis. 47, 52, 158, 214 ; Greville,
Alg. Brit. pi. 181 ; Decaisne and Thuret,
Ann. Sc. Nat. 3 ser. iii. 5; Thuret, ibid.
xvi. 6, 4 ser. ii. 197, vii. 34 ; Sachs, Bot.
284 ; Bower, Jn. Mic. Soc. 1880.

FUNA'RIA, Schreb.— A genus of Funa-
riacese (Acrocarpous Mosses), the common
species of which (F. hygrometrica) is well
known on account of the hygroscopic cha-
racter of its fruit-stalk, which twists in
drying, and untwists again when wetted,
It exhibits stomata on the neck of the
capsule (fig. 262).

BIBL. Wilson, Bryol. £r. 268 ; Berkeley,
Handb. 176.

FUNARIACE^E.— A family of Funa-
rioidese (Acrocarpous Mosses) of loosely-

FUNARIACE^E.

[ 342 ]

tufted or gregarious habit, growing on the
ground ; the stem loosely leaved, very sim-
ple. Inflorescence monoecious; antheridial
flowers disk-shaped, mostly terminal on a
special branch. Antheridia small, oval.
Archegones small, narrowly apiculate. Pa-
raphyses filiform at base, cluVshaped and
articulate at the apex. Peristorne, if pre-
sent, cartilaginous, red, streaked, with soli-
tary, oblique, trabeculate teeth.

British Genera.

Funaria. Capsule asymmetrically arched
(fig. 257); orifice oblique, very small; stalk
much curved, elongated, very hygroscopic
and twisting. Calyptra ventricose-dimi-
diate, rounded at the base, obtuse, shorter
than the capsule, or larger and truncate at
the base (fig. 258). Peristoine double, erect ;
outer of sixteen, oblique, broadly lanceolate-
subulate, trabeculate teeth, with appendices
near the point (fig. 259), chained together
at the apex by a reticular disk ; the inner
as many as the outer, opposite and adnate at
the base, lanceolate, granular, with a longi-

Fig. 257.

Fig. 258.

F. hibernica.

Fig. 257. A ripe capsule with its twisted seta.

Fig. 258. An immature capsule, covered by its calyptra.

Magnified 25 diameters.

tudinal line. Cells of the operculum circi-
nately reticulate at the apex.

Pyramidium. Calyptra squarely pyra-
midal, apiculate, entire at the base, far ex-
ceeding the capsule, totally covering it, in-
flated and persistent, bursting at the middle
of the side, longer. Capsule symmetrical,

FUNARIACE.E.

Fig. 259.

Fig. 260.

F. hibernica.

Teeth of the peristome, with appendices.
Magnified 150 diameters.

erect, pyriform, without a peristome. Oper-
culum regularly areolate.

Physcomitrium. Calyptra mitre-shaped,
split at the base into several lacinise, entire
below, much shorter than the capsule, with
a long apiculus. Capsule symmetrical,
straight, pyriform, without a peristome.
Operculum regularly areolate.

Entosthodon. Calyptra bladder-like, di-
midiate, with a long
apiculus, entire, round-
ed or truncate, readily
splitting. Capsule sym-
metrical, pear-shaped,
straight, or declined on
an arched stalk, with
or without a peristome.
Peristome, if present,
horizontal, erect when
dry, simple ; internal
wanting or scarcely
perceptible ; composed
of very short lacinise.
Teeth lanceolate, ivith-
out appendages, simple

•* i a i A. • J pji-iiui-Jiie.

or twin flat outside, Capaule . 25diams<

trabeculate within,

mostly oblique at the summit, connivent

but not connate. Operculum regularly

areolate.

AmUyodon. Calyptra hood-like, narrow,
very fugacious, longish, very slender, com-
posed at the apex of very small, thickened,
square cells. Capsule asymmetrical, pear-
shaped, straight, with a peristome and an
annulus. Peristome double : external —
teeth sixteen, short, lanceolate, obtuse, erect,
trabeculate with a slender longitudinal line ;
internal — teeth equal in number, lanceolate,
subulate, fissile longitudinally in the middle,

Physcomitrium
pyriforme.

FUNARIOIDE^E.

[ 343 ]

FUNGI.

smooth, much exceeding the external in
length, yellowish, placed on a shortly-
grooved membrane. Operculum regularly
areolate.

FUXARIOIDE^E. — A suborder of
operculated Acrocarpous (terminal-fruited)
Mosses, with broadly-oval spatlmlate leaves,
furnished with a lax cylindrical nerve, com-
posed entirely of large parenchymatous
cells, lax and parallelograimnic at the base,
lax, hexagonal, or polygonal towards the
apex, often very densely filled with chloro-
phyll-granules, more or less pellucid. Cap-
sule pyriform,apophysate, the neck (collum)
mostlv bearing stomata on its epidermis
(tig. 262).

Fig. 261.

Fig. 262.

F. hygrometrica.

Fig. 261. Portion of the annulus. Magn. 100 diams.
Fig. 262. Epidermis of the collum, with stomata.
Magn. 100 diams.

This suborder is divided into two fa-
milies :

FUNABIACEJE. Stem very simple ; ter-
restrial.

SPLACEHSTACEJE. Stem very much
branched j mostly occurring upon the dung
of animals.

FUNGI.— A class of Cellular Flowerless
Plants, growing in or upon damp (vege-
table) mould, in or upon the wood and the
herbaceous parts of living or dead plants,
upon living or decaying animal substances,
in solutions of organic matters, &c. A few
occur on bare stones or other inorganic sub-
stances, as a species of Cyphella and some
Myxomycetes; but this is quite exceptional.
A very large portion of the plants belonging
to this strange class are microscopic bodies,
only to be made out clearly by means of a
very high magnifying power. As in the
rest of the Thaliophytes, moreover, the re-
productive bodies are simple and exceed-
ingly minute in the larger forms of Fungi ;
consequently dissection under the micro-
scope is requisite when it is desired to ob-
tain a satisfactory insight into their natural
history.

The Fungi do not appear to be capable of
assimilating inorganic food, and are distin-

guished from healthy specimens of almost
all other plants by the total absence of the
colour depending on the presence of chlo-
rophyll or its red modifications, and of
starch ; for it is scarcely to be doubted that
the various colourless filamentous structures
(Leptoiniteas, &c.) occurring in infusions,
chemical solutions and the like, are Fungi,
and not Algae as some have supposed. They
are allied by certain forms with the Algae
and with the Lichens ; but they are distin-
guished from all outwardly similar forms of
the first by the spore-bearing fruits always
being elevated into the air, when mature,
although the thallus or mycelium may be
aquatic. The higher forms of Fungi can
scarcely be confounded with the higher
Algae. The separation from the Lichens is
more difficult j indeed some authors have
come to the conclusion that the Lichens
must be reduced to forms of Fungi. Yet
the presence of green gonidial cells in the
thallus will generally sufficiently distinguish
the Lichens. We shall here follow the old
plan; and the distinction ordinarily laid
down is, that the Lichens are entirely aerial
incrusting plants, while the Fungi have their
vegetative structure immersed in the me-
dium in which they grow. Some of the
epiphyllous lichens, however, originate be-
neath the cuticle.

The structures of all Fungi exhibit a well-
defined separation into two parts, namely: —
1, a mycelium (thallus), or vegetative struc-
ture, consisting of a mass of exceedingly
delicate, jointed and branched, colourless,
interlacing filaments, forming a kind of
cottony or felty mass when growing in the
earth, in vegetable structures, &c., or cloudy
flocks when growing in decomposing liquids.
In some cases, as in certain Sphcerice, the
threads are woven into a close mass, or, as
in Phallus, into filiform cords j while in the
Myxomycetes the threads become obsolete
or are replaced by a jelly-like substance re-
sembling sarcode. 2, of the reproductive
structure or fruit, which, unlike the myce-
lium, differs extremely in appearance in the
various tribes.

The mycelium may be well examined in
the "spawn" used for planting mushroom-
beds ; this cottony substance consists of the
mycelium of that plant. The formation and
growth of the mycelium of the microscopic
species, such as moulds, mildews, &c., may
be traced under the microscope by scattering
some of the dust-like fructifications (as the
blue powder of common paste-mould) upon

FUNGI.

[ 344 ]

slips of glass, and keeping them in a warm-
ish place under a bell-glass over water, for
several days. The filaments will be seen
spreading from the spores in all directions,
and often advancing to the formation of the
fructification.

The fructification of the simplest Fungi is
nothing more than a modification of one or
more cells at the end of a filament which
rises up from the general body of the myce-
lium. In TORULA, one or more globular
cells are produced at the ends of filaments
composed of elongated, more or less cylin-
drical cells (PI. 26. fig. 7) ; these globules
drop off, and develop into new mycelia. In
Botrytis (figs. 77, 78, 263), the tips of the

Fig. 263.

Botrytis (Polyactis) vulgaris.
Fertile filaments. Magnified 200 diama.

fertile filaments are branched and clothed
with heaps of spores arising from short pe-
dicels. In Penicillium (PI. 26. fig. 15), the
filament which rises up, forks at the end,
each branch forking again, and so on, until
a close tufted pencil of branches is formed,
each branch bearing a bead-like row of
spores, which drop off separately. Innu-
merable modifications of this mode of fruc-
tification are met with in the microscopic
Fungi ; and the same plan also forms the
basis of the fructification of some of the
highest forms.

The way in which the greater complexity
arises is by an increased development of the
structures supporting the layer of tissue
(liymenium) upon which the spores are
borne. Thus, in the leathery Fungi grow-
ing over damp trunks of trees and dead
wood, such as the Hydna, Thelephoree,
Hexagonia (figs. 264, 265), the conspicuous

Hexagonia glabra.
Upper surface. Nat. size.

Fig. 265.

Hexagonia glabra. Nat. size.
Lower surface, with orifices of the hymenium.

fungous mass (which is all that ordinary
observers notice) developed from a floccu-
lent mycelium imbedded in the matrix on
which the plant grows, is & fruit, composed
of dense cellular tissue, and possessing pits,
channels, cavities, or the like, the walls of
which are clothed with papillose cells, each
bearing four free sporanges, which drop off
singly to reproduce the plant. The Mush-
room, as gathered and brought to table, is
merely the ' fruit ' of the Fungus (Agaricus) ;
and similar cells bearing four sporules are
found clothing the flat sides of the paper-
like plates or ' gills' which radiate on the
under side of the flat ' cap ' of the Fungus.
(See BASIDIOSPOHES.)

A second kind of fructification is seen in
the PHYCOMYCETES, where the upright
filament arising from the flocculent myce-
lium does not bear free spores as in Peni-
cillium, Botrytis, &c., but a comparatively
large sac, filled with minute sporules; and
these sporidia are scattered by the bursting
of the sac. In the Hdvettee, Pezizce, Spa-
thulea (fig. 40), Leotia (fig. 41), &c., struc-
tures of a fleshy or leathery character, grow-
ing upon damp wood &c., we have counter-
parts to the Hydna, Thelephorte, &c., since
they have fruits arising from a flocculent

FUNGI.

[ 345 ]

FUNGI.

mycelium ; but their spore-bearing cells ap-
pear as definite groups of vesicles or sacs of
elongated form, producing spomles (usually
eight but sometimes two, multiples of two,
or multiples of eight) in their cavities. In
the Truffles (Tuber, Elaphomyces, fig. 185),
&c. the sporidia are found in twos, fours, or
eights, in sacs in the internal convoluted
substance ; while in the Puff-balls, except
Scleroderma, where the internal mass finally
breaks up into powder, the spores are deve-
loped free, as in the Agarics &c. More
minute accounts of these structures will be
found under THECASPORES and the various
genera.

It was long imagined that these two
modes of producing the spores afforded a
firm basis for the classification of the Fungi ;
but recent discoveries seem to indicate that
characters derived from the fructification
are as unsafe here as in the Alga3. Thus,
if De Bary's observations on Agancus are
correct, an asciferous structure occurs in the
highest group ^of the basidiosporous classes.
It is now, however, pretty certain that the
ascigerous structure which he found on
Agaricus mellem was a species of Hypho-
myces. The orders Coniomycetes and As-
comycetes also are confounded together by
the numerous genera which exhibit both
asci and sfy/ospores, although the latter may
perhaps be regarded as merely a modifica-
tion of the ascosporous structure. Tulasne
has also pointed out a peculiar structure
analogous to the so-called spermatozoids of
the Lichens, namely very minute cylindrical
bodies growing upon free points from the
fructifying surfaces of the Fungi; these
bodies, quite distinct from the basidiospores
and thecaspores, are called spermatia (PI. 26.
figs. 3, 4, 17 s). According to Cornu, these
germinate.

Certain more recent observations on the
sexual reproduction of the Fungi require
special notice.

In the Saprolegniae, this has been de-
scribed under ACHLYA. In Cystopus, the
conidia are stated to be formed at the ends
of the branches. Subsequently sporangia
or oogonia are produced by the swelling
of the ends of branches of the mycelium ;
while on another branch, a shoot grows to-
wards the sporangium, swells, and forms
an antheridium. A fine tube from this
bores through the sporangium, and pro-
duces fertilization.

In the Ascomycetes, a mycelium is formed
from the true spores ; on this are produced

conidia, which again produce mycelium.
On this are ultimately produced sexual
organs, consisting of the pollinodium or
antheridium, and the carpogonium or spo-
range : these are often much alike, but the
latter is usually larger, and composed of
more numerous cells. The pollinodium
forms a slender branched cell, not contain-
ing spermatozoids. It comes in contact at
the apex or through its whole length with
the sporange, which it fertilizes by diffu-
sion, as in the pollen-tube of the embryo-
sac ; but there is no fusion of contents.

In Ascobolus, the carpogonium or spo-
range consists of a curved row of cells.
The slender branches of the pollinodium
become closely applied to and fertilize it.
After this, one of the middle cells of the
carpogonium grows more than the others,
and produces buds which ultimately form
the asci.

In Peziza, the end-joints of the carpogo-
nial branches form ovate vesicles with an
apical appendage. The slender wedge-
shaped pollinodium arises on the same
branches beneath the carpogonium, with
which it becomes connected. Numerous
filaments then spring from the base of the
sexual organs, forming a dense network —
the hymenial layer, in which the asci are
subsequently produced. It appears that
Botrytis cinerea is a conidiiferous form of
Peziza (Fuckeliana). A remarkable pecu-
liarity in the sexual formation of spores in
many Fungi, as in some Algae is, they are
frequently not formed in the directly ferti-
lized cell, but in the newly formed cells
springing from its sides or base.

The sexuality of the Ascomycetes, how-
ever, is disputed.

Zoospores have now been discovered in
PERONOSPORA and CYSTOPUS.

The minutiae of the structure of the Fungi
may be treated most satisfactorily under the
heads of the orders (ASCOMYCETES, CONIO-
MYCETES &c.), since the elements are very
similar in all, while the modes of combina-
tion are very varied, and in most cases
peculiar to the families.

In consequence of the numerous disco-
veries of Tulasne, De Bary and others, the
older arrangement of the Fungi, based upon
the views of Fries, is not at present satis-
factory. We adopt, therefore, that of Sachs,
slightly modified; retaining, however, in
great measure the nomenclature for those
Fungi which are manifestly merely states
of higher forms, and are not autonomous.

FUNGI.

[ 346 ]

FUSARIUM.

I. SCHIZOMYCETES. Consisting of
threads which break up into minute cylin-
drical bodies, sometimes straight, some-
times curved, or microscopic globular par-
ticles j in the former case, sometimes at
length swarming and forming a cloudy
gelatinous mass : in solutions or in decom-
posing substances.

II. PHYCOMYCETES. Aquatic or epi-
phytous, propagated by zoospores, or by
oo^pores arising from fertilization.

1. Saprolegnice. Aquatic.

2. Peronosporea. Epiphytic.

3. Mucorini. Fermentigerous ; Sapro-
phytic (Moulds).

HI. HYPODERMIC. Epiphyllous.

IV. BASIDIOMYOETES. Spores seated
upon Basidia or Sporophores arising from
a distinct hymenium.

1. Tremettina. Tissues gelatinous; hy-
meniurn exposed.

2. Hymenomycetes. Tissue cellular, hy-
meuium inferior (Mushrooms &c.).

3. Gasteromycetes. Hymenium intri-
cate, cellular, internal (Puff-balls &c.).

V. ASCOMYCETES. Sporidia contained
in Asci (thecae).

1. Protomyces. More properly perhaps
associated with Peronosporeae.

2. Tuberacece. Hymenium as in Gas-
teromycetes (Truffles &c.).

3. Onygenece. On animal substances,
very rarely on decayed wood.

4. Pyrenomycetes. Asci contained in
perithecia.

5. Discomycetes. Hymenium superior,
disciform.

VI. MYXOMYCETES. Spores amoeboid
in germination, subsequently conjugating.

BIBL. Berkeley, Fungales, Lindley's Veg.
Kingd. : Fungi, in Hooker's Br. Fl. and
Crypt. Bot. ; also numerous papers in Ann.
N. H. ; Montague, Ann. N. H. ix. ; Corda,
Ic. Fung. 1837-40 ; Greville, Scott. Crypt.
Fl. ; Nees v. Esenbeck, Syst. Pilze ; Fries,
Syst. Myc. & Summa Veget. ; Tulasne, Fung.
Carp. 18(50-5 ; De Bary, Frucht. Ascomycet.
1863, 11 ; id. & Woronin, Morph. $c. d.
Pilze, 1870 ; Tulasne, Ann. Sc. N. 1866, vi.
217 ; Janczewsky, Bot. Zeit. 1871 ; Fuistirig,
Bot. Zeit. 1868; Baranetzki, Bot. Zeit. 1872;
Sachs, Bot. 1874, 307 ; Cornu, Ann. Sc. N.
1876 (M. M.Jn. xvii. 1877, 295); Tieghem,
Ann. Sc. N. 1875, ii. 365 (sexuality dis-
puted}] Cooke, Br. Fungi, 1871 (descript.
ofsp., $ figs, of gen.}; Brefeld, Schimmel-

pilze, 1881 ; Bary & Woronin, Morph. d.
Pilze, 1881.

FUNGUS -BED.— My cologists find this
very useful for growing the microscopic
Fungi. It is best made of a small wooden
box half-tilled with damp bog-earth, and
covered with a plate of glass. In winter it
should be kept in a warm room.

FURCELLA'RIA, Lamx.— A genus of
Cryptoneniiacese (Florideous Algae), con-
taining one common British species, growing
on rocks and stones between tide-marks,
consisting of a fastigiate, dichotomously-
divided frond, 6 to 12" high, of a brownish-
purple colour, and somewhat cartilaginous
texture. The tetraspores, which are linearly
arranged, are imbedded in the periphery of
the swollen pod-like extremities of the
branches. Conceptacular fruit as yet un-
known.

BIBL. Harvey, Mar. AJg. 147, pi. 18 C ;
Phyc. Brit. pi. 94 ; Greville, Alg. Brit. pi.
11 ; Eng. Bot. pi. 894 ; Thuret,^Lww, Sc. N.
1855, iii. 5.

FURCULARIA, Lam.— A genus of Ro-
tatoria, of the family Hydatinaea.

Char. Eye single, frontal ; tail-like foot
forked. Several species j all freshwater but
one, which is marine.

F. Reinhardtii, E. (PI. 43. fig. 34: fig. 35,
teeth). Body fusiform, truncated in front ;
foot elongate, cylindrical ; toes two, short :
length 1-120".

Found creeping upon Laomedea geni-
culata.

F. gibba. Body oblong, slightly com-
pressed, dorsallv convex, ventrally flat;
toes styliform, half as long as the body ;
length 1-96". Freshwater.

BIBL. Ehrenb. In/us. 419; Dujardin,
Inf. 648; Gosse, Ann. N. H. 1851, viii. 199.

FUSA'RIUM, Lk.— A genus of Stilbacei
(Hyphomycetous Fungi), not very satis-
factorily distinguished from FUSISPOEIUM ;
but having a firm, cellular, pulvinate, fleshy
stroma, upon which the spores are borne on
distinct sporophores glued together into an
erumpent discoid stratum. 1*. tremelloides
is common, forming roundish orange-red
spots on decaying nettle-stems; but it is
now believed to be a spore-bearing state of
Peziza fusarioides. F. roseum forms little
gregarious red dots on the stems of beans,
Jerusalem artichokes, and other plants.

BIBL. Berk. Hook. Br. Fl. ii. pt. 2.
355; Fries, Syst. Myc. iii, 469, Summa
Veg. 472; Greville, Sc. Crypt. FL pi. 20;
Fresenius, Beitr. z. My col. Heft 1. 35.

FUSIDIUM.

[ 347 ]

GAMASEA.

Fig. 266.

FUSED 'IUM, Lk. — A genus of Mucedines
(Hyphomycetous Fungi), characterized by
very delicate white or coloured flocci, which
do not form a moist or gelatinous mass as
in Fusisporium, and are very evanescent.
Spores straight, filiform. The species grow
on dead leaves, forming a thin powdery
stratum.

BIBL. Berk. Outl 357; Cooke, Br.Fung.
609; GreviUe, Crypt. Fl. pi. 102.

FUSISPO'RIUM, Lk.— A genus of Sepe-
doniei (Hyphomycetous Fungi), growing
upon vegetable substances often when de-
caying, characterized by elon-
gate fusiform curved septate
spores (fig. 266), which ul-
timately form a gelatinous
mass, the flocci being in ge-
neral more or less obscure, or
if present very delicate, the
spores in fact forming the
principal element. £s ume-
rous species are recorded as
British. F. atrovirens is de- Spores. Magn.
structive to onions. F. beta m d§MB*
common on decaying mangold- wurzel. F.
fceni sometimes runs over the cut surface of
a havstack, forming broad orange-red patches.

BIBL. Berk. Hook. Br. FL ii. pt. 2. 251,
Ann. N. H. vi. 438, pi. 14. fig. 28 ; 2 ser. vii.
178 ; Fries, Syst. Myc. iii. 442, Sum. Veget.
473 ; Greville,£c. Crypt. Fl. pi. 102. figs. 1 & 2.

FU SULI'NA, Fisch.— A genus of spiral,
hyaline Foraminifera, near Nonionina and
Nummulina, but fusiform instead of nauti-
loid, the umbilical axis of the shell being
much extended. The lateral tapering elon-
gations of the chambers in some cases are
simple, yielding symmetrical casts figured
by Ehrenberg as Borelis in the ' Mikro-
geologie ; ' but in others the chambers are
divided throughout by labyrinthic segmen-
tation, giving more complex casts and sec-
tions.

F. cylindrica (PI. 24. f . 15) and its va-
rieties form enormous masses of limestone
in the Carboniferous system, in Russia and
North America.

BIBL. Carpenter, Foram. 304; M. Mic.
Jn. 1870, 180 ; Parker and Jones, Ann.
N. H. 1872, 260; Brady, ibid. 1876,414;
Holier, Foram. Russ. 1878.

G.

GALLIONEL'LA, Bory, = MELOSIRA,
Agardh.

GALLS. — These are abnormal growths,
tumours as they might be called, produced

upon or in vegetables by the action of ani-
mals, especially insects of the order Hyme-
noptera. They were supposed to arise from
the irritation caused by a poisonous liquid
discharged into the orifice made by the
insect for the introduction of its egg. At
all events a convergence of the nutritive
juices towards the wound takes place,
whence results a kind of hypertrophy of the
tissues, and frequently the accumulation of
such substances as starch in the cells. The
forms may be regular or irregular ; most of
them are characteristic, as, for example,
the well-known nut-gall, the oak-apple,
the bedeguar of the rose, &c. Both cellular
and vascular structures contribute to form
the substance of galls. We cannot enter
into their minute structure here, but refer
to an elaborate paper by Dr. Lacaze-Du-
thiers and to Adler's more recent memoir.
Adler's plates will enable the identification
of most, if not all, the British oak-galls,
and will perhaps lead to the discovery of
others. See APHIDJE, CYNIPIDJE, and
PHYTOPTID^J.

BIBL. Lacaze-Duthiers, Ann. Sc. Nat.
3 ser. xix. 273, where also the earlier lite-
rature is given ; Adler, Zeitschr. wiss. Zool.
liii. 151 ; M'Lachlan, Ent. Mn. Mag. 1881,
xvii. 259.

GALUM'NA, Heyden, Gervais.— A ge-
nus of Arachnida, of the order Acarina, and
family Oribatea.

Char. Abdomen subglobular, depressed;
sides of the pseudo-thorax forming a salient
or wing-like angle ; legs of moderate length.

This genus approximates to Belba.

The three species, the bodies of which
are of a blackish, blackish-chestnut, or ash
colour, are found on mosses.

BIBL. Walckenaer, Arachn. (Gervais) ;
Hermann, Mem. Apter. 91 ; Koch, Deutsch.
Crustac. &c.

GAMA'SEA.— A family of Arachnida,
of the order Acarina.

Characterized by the free filiform palpi,
the chelate mandibles, and the 7- jointed
legs with two claws and a caruncle. ' Gene-
rally parasitic, and found on insects and
birds; some upon fishes, reptiles, and
mammals ; eyeless.

Dermanyssm. Body soft; last joint of
palpi smallest ; labium acute ; mandibles —
of male, chelate, outer claw very long, — of
female, ensiform ; legs with two claws and
a caruncle, anterior longest, coxae approxi-
mate. On birds and bats (PI. 6. fig. 24).

Gamasus. Body hard; labium trifidj

GAMASUS.

[ 348 ]

GASTEROMYCETES.

body with usually two dorsal plates; an-
terior legs generally longest, second pair
sometimes incrassate ; no eyes. On insects,
&c. (PI. 6. fig. 26).

Pteroptus. Body depressed; last joint
of palpi longest; legs stout, with short
joints. On bats (PL 6. fig. 39).

Uropoda. Body depressed, with a round
dorsal plate, and a deciduous funnel-shaped
anal peduncle, serving to fix the body. On
beetles, mosses, &c. (PI. 6. fig. 25).

Halarachne. Body elongate, with a dor-
sal and ventral plate ; labium bifid. In the
nostrils of a seal (Halichcerus).

See also ARGAS and CARIS.

BIBL. Gervais, Walckenaer's Apt. iii.
215 ; Duges, Ann. Sc. Nat. 2 ser. 24 ; Koch,
Deutsch. Crustac. and Uebersicht ; Murray,
EC. Entom. 157; Megnin, Paras. 113;
Kramer, Wiegm. Arch. 1876, i. 28; Tr.
Mic. Soc. 1880, 177.

GAM'ASUS, Latr.— A genus of Arach-
nida, of the order Acarina, and family GA-
MASEA.

Species numerous ; mostly parasitic upon
insects ; some found upon the ground ;
others on the higher animals.

G. coleoptratorum (PL 6. fig. 26). Found
upon dung-beetles (Geotrupes &c.). An-
terior coxse attached at a little distance from
those of the second pair ; tarsi (fig. 26 a)
with two claws and an elegant caruncle ;
palpi of moderate length ; mandibles ter-
minated by a curved hook ; fawn-coloured.

G. marginatus. Body broader behind ;
darker. Found in the human brain; also
on a fly, and on beetles.

G. muscarum. On the house-fly.

G. auris. In aural meatus of ox.

Other species.

BIBL. That of the family ; Leidy, Proc.
Acad. Phil. 1872 (Ann. N. H. 1873, xi.
79) ; Murray, EC. Ent. 158.

GAM'MARUS, Latr.— A genus of Crus-
tacea, of the order Amphipoda, and family
Gammarina.

The searcher for the freshwater Diatoma-
cese will surely meet with Gammarus pidex
(PI. 18. fig. 22), the freshwater shrimp, in
muddy brooks and streams. It attains a
length of about 1-2", and moves its curved
body through the water by means of its
caudal appendages, frequently lying on its
back or side during the process. Gervais
distinguishes G. flumatilis from G. pulex,
by the former having a dorsal spine at each
abdominal joint, whilst in the latter this is
absent.

There are twenty-three species of Gam-
mai*us, many of them marine. Talitrus sal-
tator, the sand-hopper, found burrowing in
and hopping upon the sand of the sea-shore,
also belongs to the family Gammarina.

BIBL. Desmarest, Consid. gen. Crust. ;
M.-Edwards, Crustac. iii. ; Gervais, Ann.
Sc. Nat. 1835, iv. ; Westwood, Phil. Tr.
1835 ; Bate and Westwood, Ann. N. H.
1857, xix. 135 ; Rentsh, Gamm. orn. 1861.

GANGLION-GLOBULES, or NERVE-
CELLS. See NERVES.

GAPES. — A disease occurring in poultry,
arising from entozoa (Sclerostoma and
Syngamus) in the air-passages.

GARVEI'A, T. S. Wright.— A genus of
Hydroid Polypes, fam. Atractylidse.

G. natans. Body red, tentacles yellow ;
marine; height 1" On rocks and sea-weeds.

BIBL. Hincks, Brit. Zooph. 101.

GASTEROMYCETES. — A tribe of
Basidiomycetous Fungi, characterized by
the production of their free spores upon
basidia seated on a sporiferous structure
forming convolutions in the interior of an
excavated fruit, which ultimately bursts to
allow the sporiferous structure to expand
and scatter its spores. The fruit of the
Gasteromycetes is ordinarily a globular,
elliptical, or shapeless mass, varying in size
from microscopic minuteness to the dimen-
sions of large balls, often stalked, arising
'from an inconspicuous flocculent mycelium.
This external body consists of a leathery or
membranous, simple or double sac (pe-
ridium}, which bursts in various ways at
maturity. When examined young, these
Fungi appear solid ; but as they advance,
various structures become gradually marked
out in their interior, and appear more and
more distinct until mature.

In the Nidulariacei little conceptacles are
developed in the interior of the sac-like pe-
ridium ; and when the latter is mature, it
opens like a cup or vase at its summit, ex-
hibiting the conceptacles w'ithin, lying like
eggs in a nest. These conceptacles are
hollow, and lined with basidia bearing free
spores.

The Trichogastres exhibit in most cases
the appearance of a leather ball, arising
from an inconspicuous flocculent mycelium ;
but in Broomeia the peridia are imbedded
in large numbers in a common fleshy matrix.
The internal structure differs to a consider-
able extent in its earlier stages. The peri-
dium is either single or double, the outer
being often quite free, and becoming everted

GASTEROMYCETES. [ 349 ] GASTEROMYCETES.

Fig. 268.

Fig. 267.

Fig. 267.
Fig. 268.

Polysaccum crassipes.
Natural size.
Section from ditto, showing the loculi.

Polysaccum crassipes.

Cells of the hymenium, with basidia and spores.
Magn. 400 diams.

at the time of dehiscence. The interior of
Polysaccum (fig. 268) and Scleroderma (fig.
270) consists, in the early state, of a mass of
cellular matter, formed by the prolongation
of the peridium, in the form of septa, in all
directions into the interior, so as to divide
it into chambers, each of which is lined
with a hymenium or concep^tacle, hollow in
the centre, into which project the ends of
the filaments, bearing basidia with two to
six spores. At the epoch of maturity all
the internal structure has vanished, except
the spores and detached particles of the
filaments on which they were developed ;
and these escape, on the bursting of the now
bag-like peridium, as a fine powder. In
Lycoperdon, &c., it is not the peridium

Fig. 270.

Fi«r. 271,

Scleroderma vulgare.

Fig. 270. Portion of the internal mass. Magn. 200

diams.
Fig. 271. Cells of the hymenium, with basidia and

spores. Magn. 400 diams.

which is continued inwards to form cham-
bers ; it forms a single or double sac, con-
taining a fleshy substance (glebd), hollowed
out into sinuous cavities clothed with
basidia. In course of ripening, the spongy
mass disappears, leaving only a collection
of minute spores and filamentous fragments,
which are emitted by the bursting of the
peridium, — a process exhibiting many cu-
rious peculiarities in this group.

The Phalloidei are roundish or ovoid
fleshy balls in their earlier stages, but when
opened exhibit a distinct peridium and a
central lacunose sporiferous structure. The

Fig 272.

Lycoperdon cselatum.

Section of the cfleba showing the loculi, on the walls of

which the spores are produced.

Magn. 200 diams.

peridium consists of two layers, an inner
and an outer, united by firm gelatinous

GASTEROMYCETES. [ 350 ] GASTEROMYCETE8.

tissue traversed by transverse membranous

septa, and exhibits a tendency to split, like

an orange, into quarters. When

the peridium bursts, which it Fig. 273.

usually does at the apex, the

central sporiferous structure

emerges, under various forms.

In Phallus it is a capitate or

clavate column ; in Clathrus

(fig. 273), an elegant, globular,

fleshy trellis j in Aseroe, a co-

lumn with a stellate head, &c.

In all cases, the spores, which

are developed on convolutions

of the fleshy sporiferous mass

(glebd), on basidia, are found The sporiferous

detached and confluent into a frame -

wet viscid mass adherin to the

sporiferous surface at the time peridium.
this has emerged from the 1'loth nat- 8ize-
peridium and expanded to its full size.
This wet condition of the mature sporife-
rous layer is distinctive between the Phal-
loidei and the Hymenomycetes, to which
they bear many relations.

The Hypogaei receive their name from
their subterraneous habit of growth ; in
which they resemble Truffles, a tribe of As-
comycetes bearing much external similarity
to these plants (see TUBERACEI). The
general character is that of globular or de-
pressed balls, growing underground, sessile
on a flocculent mycelium. They exhibit a
peridium enclosing a fleshy gleba, excavated
into sinuous cavities lined by a membrane
bearing basidiospores. These fruits do not
burst, but set free their spores by decaying.

Lastly, the Podaxinei bear much resem-
blance to the Trichogastres ; but they always
contain a central fleshy column, called the
hymenophore. The young plants exhibit a
peridium passing internally into a fleshy
mass hollowed into labyrinthiform cavities
(fig. 275), with a solid column in the centre
of all. The cavities are lined by a mem-
brane bearing basidiospores (fig. 277). The
gleba sometimes breaks up into a pulverulent
mass of spores and filaments ; sometimes it
is permanent. The internal structure of
this order presents many points of great
morphological interest, but rather as regards
the mode of arrangement and composition
of the tissues than the character of the ul-
timate elements themselves, which consist
of the ordinary filamentous interwoven tis-
sue of Fungi in the general mass of the
structure, and of globular loosely packed
cells in the sporiferous regions.

Fig. 274.

Fig. 275.

Fig. 276.

Fig. 277.

Secotium erythrocephalum.

Fig. 274. Natural size.

Fig. 275. Vertical section.

Fig. 276. Vertical section through the head, showing
the labyrinthiform cavities.

Fig. 277. Portion of a septum dividing the loculi, bear-
ing basidia. Magnified 400 diameters.

Synopsis of the Families.

PODAXINEI. Peridium dehiscent, en-
closing a sinuously excavated, fleshy, spori-
ferous mass, falling to powder or permanent
when mature, with a central solid column.

HYPOGJEI. Peridium indehiscent, coat-
ing a fleshy, sporiferous mass. Subter-
raneous.

PHALLOPDEI. Peridium dehiscent, en-
closing a fleshy, sporiferous mass, which
emerges from the burst peridium as a club-
shaped or capitate column, or a globular
network of wrinkled fleshy precesses, coated
on the sporiferous surfaces with a dark-
coloured foul-smelling slime (composed of
minute spores imbedded in mucus).

TRICHOGASTRES. Peridium double, more
or less distinct, dehiscent, enclosing a mul-
tilocular, fleshy, sporiferous mass, which
finally breaks up into dust, without a cen-
tral column.

GASTROCH^TA.

[ 351 ]

GENERATIONS.

NIPULARIACEI. Peridium dehiscent, and
then forming1 a cup or nest, containing one
or many globose, oval or discoid concep-
tacles, lined with filaments hearing spores.

BIBL. See the Families.

GASTROCELE'TA, Duj.— A genus of
Infusoria, of the family Enchelia (Duj.).

Char. Body oval, with one side convex,
the other heing traversed by a longitudinal
furrow, which is furnished with vibratile
cilia, principally at the ends.

G.fssa (PL 31. fig. 7). Body semitrans-
parent, colourless, oval, truncated in front,
with a very minute blunt point at the
middle of the posterior margin, convex and
smooth above. Freshwater; length 1-400".

BIBL. Duiardin, In/us, p. 385.

GAUDRYI'NA, D'Orb —A Textularian
Foraminifer, having the early chambers
arranged triserially, as in a Verneuiline,,
making the shell three-keeled at first ; but
it subsequently becomes compressed and
wrinkled, the chambers being alternate
with biserial growth, as in Textularia. The
aperture is usually, as in Textularia, a slit
on the inner wall of the chamber ; but it
may be almost terminal and somewhat
rounded and pouting, thus passing into He-
terostomella. Some GaudryincB are twisted
and Buliminoid. Fossil and recent. PI. 23.
fig. 48, G. pupoides, D'Orb., in the Chalk.

BIBL. D'Orb. For. Foss. Vim. ; Parker &
Jones, Annals N. H. ser. 3, xi. 127.

GELATINE.— This chemical proximate
principle constitutes the basis of the various
forms of connective tissue, as existing in
the true skin, areolar tissue, tendon, liga-
ments, the swimming-bladder of fishes
(isinglass) ; also of bone &c.

It possesses no microscopic characters ;
it forms a most valuable vehicle for the
colouring-matters of liquids for injection.

GELID'IUM, Lamx.— A genus of Cry-
ptonemiaceae (Florideous Algae), of which
one species (G. corneum) is very common
on our shores. It has a red, pinnated,
horny frond, from two to six or eight inches
high ; very variable in the appearance of
its pinnate subdivisions; both spores and
tetraspores are found on the ramules, the
former in favellidia immersed in swollen
ramules.

BIBL. Harvey, Mar. Alg. 137, pi. 17 B,

Phyc. Brit. pi. 53.

GEMELLA'RIA, Sav. — A genus of

Cheilostomatous Polyzoa, of the order In-

fundibulata, and family Gemellariidse

(Eucratiidae, H.)

G. loriculata (PL 36. fig. 26). Cells in-
versely conical, obliquely truncate. Com-
mon a few fathoms below low water-mark.

BIBL. That of the family.

GEMELLA'RIIDJE.— A family of Chei-
lostomatous Polyzoa, of the order Infundi-
bulata.

Distinguished by the unjointed zoary,
and the cells being opposite in pairs. Two
genera :

Gemellaria. Cells jointed back to back,
all the pairs facing the same way ; orifice
oval, oblique; no birds'-heads (PI. 36.
dig. 26).

Notamia. Each pair of cells arising
from the next pair but one below it by
tubular prolongations ; pipe-shaped birds'-
heads above each pair (PL 36. fig. 21).

BIBL. JohnstoQ, Br. Zooph. 293 ; Busk,
Mar. Polyzoa, 34 ; Gosse, Mar. Zool. ii. 14 ;
Hincks, Polyz. 17.

GEMMAE. — This term is applied to those
cellular structures, formed in Flowerless
Plants, which become detached, and repro-
duce the individual independently of the
spores.

GEMMULI'NA, D'Orb. See BIGE-

NERINA.

GENERATIONS, ALTERNATION OF.—
The ordinary plan upon which the repro-
duction of animals is effected, viz. that of
sexes, involving the action of the spermatic
secretion upon the ova, and the subsequent
series of changes ultimately giving rise to
new individuals resembling tne parents, is
in some instances departed from ; and the
embryos of certain animals, after their escape
from the ova, do not become directly de-
veloped into individuals resembling the
parents, but produce a new, larval kind of
being, which produces generations of the
same larval or other kinds, the last of which
resemble the original parents.

While, therefore, in animals reproduced
by the ordinary sexual process, the new in-
dividuals resemble each other, or differ only
in sex, in those which produce these alter-
nate or intermediate generations the new
individuals differ from the parents and even
from each other, until the last of the series
returns to the state of the first parents.
This mode of reproduction has received the
above name, from the alternation of the
larval generations with the ordinary sexual
form.

Many instances of this process are men-
tioned under the heads of the Classes &c.
in which they occur ; as under ACALEPH^E,

GENERATIONS.

[ 352 ]

GENERATIONS.

ENTOZOA, TJENIA, &c. Thus,
for instance, in the Acalephae, the ciliated
embryo (PI. 49. tig. 6) produced by the
ordinary sexual process becomes fixed (fig.
7), and passes into the state of an asexual
polype (fig. 8) ; it then reproduces new
individuals from gemmae and stolons (fig. 9),
ultimately becoming segmented (fig. 10),
and producing new individuals which re-
semble the sexual parents. The interme-
diate or nurse forms are those represented
in figs. 7-10. Again, in Tcenia, the Cysti-
cercus or Echinococcus forms the nurse, pro-
ducing new individuals by gemmation, these,
on reaching the alimentary canal, becoming
transformed into Tcenicp with sexual organs.

But the alternation of generations, or a
modification of it, also occurs in animals in
which sexes are not known to exist, as in
some Infusoria and Rhizopods. In these,
the ordinary plan of reproduction by di-
vision and gemmation is departed from,
and an animal differing from the parent, or
a nurse-form resembling or identical with
Acineta andActinophrys, is produced, which
gives rise to embryos subsequently growing
into the parent form. But in these in-
stances the nurse- form is the result of a kind
of metamorphosis, rather than of generation.

In the Aphidae, the process is exhibited
by the repeated formation of viviparous
broods of beings, from apparently female
insects, without impregnation, the final
progeny being sexual. This is called par-
thenogenesis.

The phenomena designated by the phrase
alternation of generations are also strikingly
exemplified in the vegetable kirgdom ; but
the conditions are very complicated, and the
analogies with those occurring in animals
somewhat diificult to trace. The Mosses,
Hepaticae, and Ferns afford very clear
analogies to the Medusae ; and others admit
of being made out ; but it appears to us that
Steenstrup and others have confounded va-
rious distinct points, in the parallel drawn
between the alternation of generations of
animals and the metamorphoses (commonly
so-called) of plants. We will endeavour
to give a summary of the general facts
connected with the doctrine.

1. All animals and plants reproduced by
a sexual process (and there is reason to
believe that this will ultimately be found
universal), originate from a simple proto-
plast or cell, and undergo a series of changes,
in the course of their development to the
complete form endowed with sexual organs,

in which they assume forms analogous to
animals (or plants) belonging to classes of
lower (simpler) organization.

2. In the highest animals, the metamor-
phoses are intra-uterine, as in most of the
Mammalia ; in the lower animals these
metamorphoses are in part or wholly extra-
uterine. In the higher plants the changes
are partly intra-uterine (t. e. the embryo has
already become a leafy axis within the
ovary, but it becomes perfected into the
sexual form subsequently), in the lower
partly or wholly extra-uterine.

3. The lower animals and all plants are
capable of an asexual or vegetative repro-
duction, by the isolation and separation of
a portion of their substance.

4. Many animals and all plants are ca-
pable of being multiplied by this vegetative
reproduction in their intermediate stages of
extra-uterine development ; and in such cases
the reproduction, fissiparous, gemmiparous,
or other, assumes the character peculiar to
the class to which the intermediate form is
analogous (e. g, the polypiform reproduction
of the Acalephae, the confervoid growth
and multiplication of the proembryo of the
Mosses). The product of the vegetative
reproduction is either like or unlike the
body which produces it : in the former case
the vegetative reproduction will be re-
peated ; but in the latter case the product is
usually provided with sexual organs, and
the cycle of development is completed by
the reproduction of a fertilized ovum. In
the latter case we have what is called an
alternation of generations.

It will be evident that we here exclude
from consideration the metamorphoses
within the sphere of the individual shoot on
plants — that is, the metamorphosis of the
leaf, the morphological element of the higher
plant. It appears to us that these are not to
be taken as parallels to the metamorphoses
of animals comprehended by Steenstrup
under the name of alternation of genera-
tions, which would rather be found in the
cases where bulbs, bulbils, tubers, &c. ap-
pear in the place of shoots, as the product
of branch-buds. The analogy would hold
also with the gemmae of the Mosses, &c., and
with the gonidia of the Thallophytes. Our
space does not admit of a more minute exa-
mination of the subject. Illustrations of
the phenomena in vegetables will be found
under FERNS, MOSSES, CONFEBVOIDE^E,
LICHENS, certain Fungi, e. g. ERYSIPHE,
PENICILLIUM, &c.

GENERATION.

[ 353 ]

GEPHYPJA.

Strictly speaking, the term alternation of
generations is incorrect ; the process really
consisting of an alternation of reproduction
by gemmation, with that by sexual repro-
duction.

BIBL. Steenstrup, Altern. of Gen. (Ray
Soc. 1845) ; Owen, Parthenogenesis, and Ann.
N. H. 1851, ii. 59; A. Thomson, Cycl. An.
iv. Suppl. ; Braun, Rejuv., Ray Soc. 1853 ;
Henfrey, Ann. N. H. 2 ser. ix. 441; Radlko-
fer, Befrucht. 1857, Ann. N. H. 2 ser. xx.
241 ; Huxley, Inv. and Verteb. ; Leuckart
(Ceddomyia "larva), Ann. N. H. xvii. 1866,
161; Sachs, Sat. 227; Nicholson, ZooL
1878, 33.

GENERATION, SPONTANEOUS; some-
times called equivocal generation, epige-
nesis, or heterogeny.

The doctrine of spontaneous generation
was considered to have become a matter of
history. We noticed under AIR (p. 24), the
experiments which were supposed to have
negatived the idea that microscopic plants
and animals derive their origin from the
direct transformation of decaying animal
and vegetable remains. We have also there
stated the modes by which the lower forms
of organic life, most commonly found in de-
composing infusions, propagate with extra-
ordinary rapidity. More recent experi-
ments have shown conclusively that this
doctrine is untenable.

The supposed occurrence of particular
species of Entozoa within the bodies of
other animals, not to be found in any other
situations, was formerly considered to find
a ready explanation in the doctrine in ques-
tion. Later investigations, however, have
proved that these supposed species are larval
or other forms of true species of this Class,
which do not attain their perfect develop-
ment on account of their not existing in a
suitable locality.

BIBL. Schultz, Fogg. Annal. xli. 184;
Helmholtz, Jn. prak. Chem. xxxi. 429 ;
Gross, Sieb. undKoll. Zeits. iii. 68; Reissek,
Ber. Wien, 1851 ; Pineau, Ann. Sc. Nat.,
ZooL 1845, 1848; Pasteur, Compt. Rend.
1860, li. 348, 675, and 1861, Hi. 1142;
Pouchet, Heterogenie, 1859 ; id. Nouv. Exp.
1864 ; Bastian, Beginnings of Life, 1872 ;
Evolution of Life, Med. Press and Circular,
1872 ; Tyndall* Putrefaction, 1881.

GENICULA'RIA, De Bary.— A genus
of Desinidiacese.

Char. Cells cylindrical, elongate, neither
constricted nor incised, united into long
filaments.

Fig. 278.

Endochrome forming 2 or

spirals (left-handed). Conjugating joints
geniculate.

G. spirotania (PI. 51. fig. 36). Cells
slightly expanded at the ends, cell-walls
rough. Frankfort.

BIBL. De Bary, Conjug. 77 ; Rabenhorst,
Fl. Alg. iii. 156; Pritchard, Inf. pi. 3. fig. 31.

GEO'DIA, Lamk. — A genus of marine
sponges. Distinguished by the rounded
form, the solid structure permeated by
sinuous canals, and the solid external crus-
taceous covering formed of globules of silex.

G. Zetlandica. Deep water.

BIBL. Bowerbank, Brit. Spong. ii. 4o.

GEOLOGY. — The microscopic investiga-
tion of geological products is treated of
under ROCKS.

GEOPHTLUS, Leach. — A genus of
Chilopodous Myriapoda.

G. longicornis, with the body brownish-
yellow, slender, consisting of more than 40
joints, is common in garden-mould, under
flower-pots, &c. G. subterraneus is phospho-
rescent. See MYRIAPODA.

GEOR'GIA, Ehrh.— A
genus of Mniaceous Moss-
es, called, from the four
teeth of the peristome,
Tetraphis and Tetrodon-
tium ; but these names are
of later date thanEhrhart's
(1780). G. Mnemosyne
presents, besides its male
and female inflorescence,
a peculiar form of terminal
leafy bud (fig. 278), which
produces stalked gemmae
in the interior. In the
figure, numerous arche-
gonia are also shown.

Georgia Browniana,
C. Miiller, = Tetraphis
Brown., Grev. Georgia Muemosyne.

G. Mnemosyne, Ehrh. A shoot with two

= Tetraphis pellucida, terminal leafy buds.
Hedw. Magn. 15 diameters.

GEPHYR'IA, Arn.— A gemis of Diato-
maceaa.

Char.— Fr. arcuate, attached, destitute of
cellulate annuli. and septa ; hoop sublamel-
late, finely striate. Valves arcuate, with
one median and several lateral costse, dis-
similar ; inferior with the costse disappear-
ing below the ends of the valve ; superior
with them reaching the summit.

G. incurvata. Ichaboe and Patagonian
guano.

G. media. Calif ornian guano.

2A

GERANIUM.

[ 351 ]

GILLS.

G. TelfairicB. Mauritius.

BIBL. Arnott, Qu. Micr. Jn. viii. 20 ;
Greville, Micr. Tr. 1866, 77, 122 (fig.)-

GERA'NIUM.— The sepals of the com-
mon wild Geraniums and the garden Pelar-
yonia form pleasing objects when dried and
mounted in Canada balsam, the cells con-
taining regularly arranged raphides (Que-
kett, Ann. N. H. 1846, xviii. 82).

GER'DA, 01. & L.— A genus of Infuso-
ria, fam. Vorticellina.

Char. Sessile, resembling Scyphidia, but
distinguished by the absence of the pos-
terior sphincter or sucker.

G. glans (PI. 52. fig. 2).— Body elongate,
cylindrical or clavate behind; contractile
vesicle posterior, continued into a long ves-
sel. Freshwater.

BIBL. Clap. & Lachm. Infus. 117 ; Kent,
Inf. 657.

GERMINAL VESICLE OF ANIMALS.
See OVUM.

GERMINAL VESICLE OF PLANTS.—
This structure, the existence of which is
now universally admitted by physiological
botanists, is the germ of the future plant,
formed from one of the protoplasmic germ-
masses which exist before impregnation
(Tulasne is doubtful whether before) in the
embryo-sac of Flowering Plants. In most
cases three masses are originally produced,
as in Orchis (PI. 47. fig. 4) ; and in rare
instances two of these are fertilized, and two
embryos produced in one seed ; sometimes
only one exists, and ordinarily only one is
fertilized. This becomes at first elongated
into a cellular filament called the suspensor,
which is cut off by septa into several cells,
the last of which usually becomes the
embryonal vesicle or embryo-cell, which is
then developed into the embryo (fig. 192,
page 280). See OVULE and EMBRYO.

GERMINATION.— The act of develop-
ment of a seed or spore into a new plant.
The phenomena attending the germination
of all the Cryptogamic plants require the
aid of the microscope for their investiga-
tion, and are in most instances highly in-
teresting and important in a physiological
point of view. For particulars, see the
classes of Flowerless Plants.

GER'RIS, Latr.— A genus of Hemipte-
rous (Heteropterous) Insects, of the family
Hydrometridae.

Gerris lacustris is everywhere seen skim-
ming the surface of water. It has the basal
joint of the antennae longest, the four hind
legs very long and at a great distance from

the fore legs. The legs do not possess any
special structure by which they are enabled
to repel the water, beyond a number of
short hairs.

Telia rivulorum, with the basal joint of
the antennas longest, the legs of moderate
length and equally apart, and Hydronwtra
stagnorum, with the first and second joints
of the antennas short, the third being the
longest, are allied members of the same
family, and are commonly met with on the
surface of pools, &c. The elegantly sculp-
tured eggs, and the curiously placed eyes of
Hydrometra, are interesting objects.

In the anterior tarsi of Telia, minute mem-
branous retractile lobes have been described.

BIBL. Westwood, Introd. ii. 467, and
Syn. 119: Douglas and Scott, Brit. Hemipt.

GIGAR'TINA, Lamx.— A genus of Cry-
ptonemiaceae (Florideous Algae), with car-
tilaginous irregularly-divided fronds, the
internal substance of which is composed of
rather lax tissue, the outer of dichotomous
filaments perpendicular to the surface,
strongly united by their moniliform termi-
nations (fig. 279). Four British species are

Fig. 279.

Gigartina pistillata.

Transverse section of the frond.

Magnified 50 diameters.

known, growing from 2 to 6 inches high,
of a dull purple colour. Reproduced by
spores (in favellidia) and tetraspores scat-
tered among the peripheral filaments.

G. acicularis (PI. 4. fig. 17).

BIBL. Harvey, Mar. Alga, 139, pi. 17 C ;
Greville, Alg. Brit. 146, 147, pi. 16.

GILLS OF FISHES. — These organs form
beautiful and favourite injected objects.
They must be injected from the heart, or
frolri the branchial artery, which ascends

GILLS.

[ 355 ]

GLANDS.

from the heart much in the same manner |
as the pulmonar}7 artery ascends from the
heart of the higher animals. It may be
remarked that the heart of fishes is situated
much nearer to the anterior end of the body
than in the Mammalia.

BIBL. Stannius, Vergl. An. ; Lereboul-
let, An. Cotnp. de VAppar. Respir. ; Hyrtl,
Med. Jahrb. (Ester. Staat. bd. 24 j Leydig,
Histol. 382 j Gegenbaur, Vergl. An. 565.

GILLS OF INSECTS, or branchiae. — These
are hair- or leaf-like processes (PI, 35. figs.
2 y, 15, 19, 21) projecting from the surface
of the body, and containing one or more
tracheae and their ramifications, which
communicate with those of the body gene-
rally. Insects furnished with gills or bran-
chiae have no occasion to rise to the surface
of the water in which they live, the diffusion
by which the respiratory process is effected
taking place between the gaseous contents
of the tracheae and those of the water,

GINAN'NIA, Montague. — A genus of
Cryptonerniaceae (Florideous Algae), con-
taining one British species, G.furcellata, a
rare, pinky-red sea-weed, about 2 to 6 in-
ches long, with a dichotomous, terete, mem-
branaceo-gelatinous frond, the divisions of
which have a kind of fibrous axis. The
spores are produced in spherical concep-
tacles imbedded just beneath the surface of
the frond.

BIBL. Harvey, Mar. Algce, 148, pi. 19 C j
E. Botany, pi. 1881.

GINGER. — This substance finds a place
here on account- of its liability to adultera-
tion when sold in the form of powder. It
consists of the rhizomes of Zingiber offi-
cinale (N. 0. Zingiberaceae) . The bulk of
the structure consists of parenchymatous
cellular tissue with pitted walls, containing
scattered starch-granules, and here and
there filled with a combined mass of starch-
granules and yellow colouring-matter of
very distinct character ; besides these, occur
the pitted ducts and a small quantity of
woody fibre. The starch-grains nearly re-
semble those of the species of Curcuma
which yield East-India arrowroot. Adul-
teration is effected with cheap starches
(sago-, wheat-, or potato-flour), which may
be detected by the form of the granules ;
while MusTABD-husks and CAYENNE pepper
are employed to give pungency to the same
reduced articles. The characters of these
substances are given under their respective
heads.

BIBL. Hassall, Food $c. p. 390.

GLANDS OF ANIMALS. — Glands are
organs, the general function of which is to
separate from the blood certain compounds
destined to perform some special office in
the economy. They are divided into true
or secernent glands j and vascular glands.

The secernent glands, the secretions from
which escape either by rupture, or through
ducts, are thus arranged : —

1. Glands consisting of closed vesicles
which dehisce laterally : the Graafian vesi-
cles of the ovary, and the follicles (Nabo-
thian) of the cervix uteri.

2. Glands composed of cells reticularly
united : the liver. (See LIVER.)

3. Racemose or aggregated glands, in
which aggregations of roundish or elongated
glandular vesicles occur at the ends of the
excretory ducts. These are either, «, sim-
ple, with one or but few lobules, comprising
the mucous glands, the sebaceous and the
Meibomian follicles ; or, b, compound, with
many lobules, the lachrymal and salivary
glands, the pancreas, the prostate, Cowper's
and the mammary glands ; in this category
must also be placed the lungs.

4. Tubular glands, in which the secreting
elements have a more or less tubular form.
These are either, a, simple, consisting of
one or but few caecal tubes — including the
tubular gastric and intestinal (Lieberkiihn's),
the uterine, sudoriparous and ceruminous
glands; or, 6, compound, consisting of nu-
merous reticular or ramified glandular canals
— comprising the testis and the kidney.

The vascular glands, which have no
ducts, and the contents of which escape by
transudation, are subdivided into —

1. Those composed of large and small
cells imbedded in a stroma of connective
tissue ; comprising the supra-renal capsules,
the anterior lobules of the pineal gland, and
the pituitary body.

2. The closed follicles, consisting of a
ba&ement-membrane, an epithelial lining,
and transparent contents, forming the thy-
roid gland.

3. The closed follicles, with a capsule of
areolar tissue and contents consisting of
nuclei, cells, and liquid, to which belong, «,
the solitary follicles of the stomach and
intestines ; 6, the aggregated follicles of the
small intestines, or Peyer's glands, in ani-
mals also those of the stomach and large
intestines j c, the glandular follicles of the
root of the tongue, and of the pharynx and
the tonsils ; and, d, the lymphatic glands.

4. Here belongs the spleen, consisting of

2A2

GLANDS.

[ 356 ]

GLANDS.

a cellular parenchyma containing numerous
closed follicles like the last.

5. The thynius gland, in which aggre-
gated glandular vesicles open into a com-
mon closed canal or wide space.

The glands are further noticed under
their respective heads.

BIBL. Kolliker, Mik. An., and Geivebe-
lehre ; Henle, Allg. An. ; Wagner, Handiv.
Phys. ; Todd and Bowman, Phys. Anat. ;
Carpenter, Physiol. ; Frey, Histol. 374.

GLANDS OF PLANTS.— The glands of
plants are special structures formed of cel-
lular tissue, in which are produced secretions
of various kinds, such as oils, resins, £c.
They are ordinarily more or less closely
connected with the epidermal tissues, but
not in all cases, the latter instances forming
a kind of transition to the receptacles of
special secretions, turpentine-reservoirs &c.,
found in the interior of the stems of many
plants. Glands may be conveniently divided
into external and internal : the former are
sessile, or stalked (when they present the
character of grandular hairs, of various
forms) ; while the latter are generally visible
externally as transparent dots scattered
over an organ, such as a leaf, giving it the
appearance of having been pricked all over
with a pin; when of more considerable
dimensions, and with thicker walls, they
produce tuberculation of the surface, as on
the rind of the orange, &c.

External glands. These may be subdivided
into simple and compound.

Simple external glands are either sessile
vesicles or hairs, composed of a single vesi-
cular or elongated epidermal cell filled with
secretion ; or they are hairs composed of a
simple row of cells, one or more of which
are filled with secretion. Examples of this
may be found in the epidermis of Primula
sinensis, Gilia tricolor, Erodium cicutarium,
Achimenes (PL 28. fig. 32), Stachys, Marru-
bium, Digitalis purpurea (fig. 33), Antir-
rhinum majus (fig. 34), (Enothera, Helk-
borus foetidus, Scrophularia nodosa (fig. 41),
Sempervivum, Salvia, Thymus, Mellissa,
Mesembryanthemum, Garden Chrysanthe-
mum (fig. 30), &c.

The stings of the nettles are to be placed
here; they consist of very long, tapering,
single hairs, with an obtuse point, and a
bulb-like expansion at the base, imbedded
in a dense layer of epidermal tissue (PL 28.
fig. 8). The hair is tilled with the poisonous
secretion. When the point touches the
skin, it breaks off and allows the escape of

the fluid contents, which are squeezed out
by the pressure, and probably by the tension
of the tissue around the bulb.

Compound external glands differ from the
simple only in the fact that they are com-
posed of a greater or a smaller number of
cells combined into a mass, usually of sphe-
rical or allied form. They may be sessile,
or stalked upon a simple or compound hair.
Examples of sessile form occur in Dictamnus
albus (PL 28. figs. 38, 39), RoUnia viscosa,
the leaf of the mulberry and the HOP
(fig. 14), and the stipular glands of C'm-
chona, Galium, &c. ; of the stalked, in the
Rose (fig. 46), species of Ktibus, Drosera,
and on many aromatic or viscid plants.

Internal glands. These consist of cavities
in the subepidermal tissue, of variable size,
bounded by a firm layer of cells, and filled
with oily or resinous secretions. They ap-
pear to be formed either of one cell, when
small, or, when large, of a definite mass of
cells, which, after the production of the
secretion, have their walls obliterated so as
to form a large chamber ; possibly, however,
some may be intercellular spaces into which
the secretion is poured out. Examples of
moderate dimensions are found in the leaves
of Dictamnus, Magnolia (PL 28. fig. 12),
Hypericum perforatum, and other species,
Myrtacece, Ruta graveolens (fig. 11), &c.
Very large glands of this kind contain the
oil in the rind of the orange (fig. 280) and
other species of Citrus.

Fig. 280.

Section of the rind of an orange, showing the internal

glands, E, u.
Magn. 50 diams.

The nectaries of flowers have their tissue
metamorphosed into a condition resembling
that of the secreting part of glands ; and
the hairs of the stigma of Flowering Plants
produce a secretion at the period of impreg-
nation. Brongniart has lately pointed out
the existence of internal glands in the dis-
sepiments of the ovaries of the petaloid
Monocotyledons. These structures form a
transition to the turpentine-canals &c. of
the Coniferse. (See SECRETING ORGANS
of Plants.) The Gummi-Keulen of Meven

GLANDULINA.

[ 357 ]

(cystoliths of Weddell) are also related to
glands. (See RAPHIDES.)

Bennett draws attention to certain glands
imbedded in the leaves of Drosera, Pingui-
cula, and Callitriche, at first sight resem-
bling stomata, with two papill£e. They are
supposed to be related to a carnivorous func-
tion. Similar structures seem to exist in
leaves of the garden rhubarb (PI. 2. fig. 14).
BIBL. Meyen, Secretiomorg . d. Pftanzen.
Berlin, 1857 ; Brongniart, Ann. Sc. Nat.
4 ser. ii. 5 ; Lawson, Ann. N. H. 2 ser. xiv.
161 ; Trecul, Ann. Sc. Nat. 4 ser. iii. 303 ;
Ann. N. H. 2 ser. xvi. 146 ; Tieghem, Ann.
Sc. Nat. 1872 ; Sachs, Sot. 92 ; Bennett, M.
M. Jn. 1876, xv. 1.

GLANDULI'NA, D'Orb.— A Nodosa-
rian Forarninifer. It has a free, regular,
straight, ovoidal shell ; globular, almost com-
pletely embracing chambers, the last being
convex and prolonged ; and a round, minute,
terminal orifice.

G. Icevigata (PL 23. fig. 28). Recent and
fossil. Common in the Lias and Chalk.

BIBL. D'Orbigny, For. Foss. Vien. 28;
Morris, Er. Foss. 36 ; Parker and Jones,
Ann. N. H. 2 ser. xix. 280.

GLAUCO'MA, Ehr.— A genus of Infu-
soria, of the family Trachelina, E.

Char. Body ciliated all over; mouth
longitudinal, oval, without teeth, placed
laterally near the anterior third or fourth
of the body, and furnished with one or two
tremulous laminae or lips.

Stein describes the encysting process as
occurring in one species.

G. scintillans, E. (PI. 31. fig. 8). Body
colourless, slightly depressed, elliptical or
ovate ; sacculi large; length 1-290". Fresh-
water, and in infusions (of hay, &c.).

G. viridis, D. Body green, oval ; mouth
large, nearer the middle than the anterior
end of the body ; length 1-630". In pu-
trid rain-water collected in an empty wine-
cask coated with cream of tartar.

BIBL. Ehrenb. In/us. 334 ; Dujardin,
In/us. 475 ; Stein, In/us. 250.

GLEICHENIA'CEJE. — An order of
Ferns, distinguished by the sori of few (2-10)
obliquely amralated sporangia, which open
vertically (fig. 282). Genera :

Gleichenia. Sporangia collected in round-
ish sori. Indusium absent. Leaves forking.
Exotic (figs. 281 & 282).

Platyzoma. Sporanges collected in point-
like sori. Indusium spurious, formed by the
revolute margin of the leaf. Leaves undi-
vided.

GLENOPHORA.
Fig. 281.

Fig. 282.

Gleichenia.

Fig. 281. Fertile pinnules with sori. Magn. 5 diama.

Fig. 282. Sorus composed of four crucially arranged

capsules. Magn. 40 diams.

GLENODIN'IUM, Ehr.— A genus of
Infusoria, of the family Peridinsea.

Char. Carapace membranous, rounded
or oblong, with one or more distinct furrows
furnished with vibratile cilia ; an elongated
or horse-shoe-shaped red (eye-) spot pre-
sent ; no horn-like processes.

These organisms are doubtful Infusoria.
Thev are common in pools and bog-water.

G. cinctum (PL 31. fig. 10 a, 6). Ovate
or subglobose, ends obtuse, yellow; cara-
pace smooth; eye-spot large, transverse and
semilunar ; length 1-576".

G. apiculatum (PL 31. fig. 10 c). Oval,
ends obtuse, greenish yellow ; carapace
smooth ; eye-spot oblong ; length 1-480".

G. tabtilatum. Oval, greenish yellow ;
carapace granular, reticulated with promi-
nent lines ; ends acute or denticulate ; eye-
spot oblong; length 1-480".

BIBL. Ehrenberg, Inf. 257; Dujardin,
Inf. 373 ; Kent, Inf. 446.

GLENOM'ORUM, Ehr.— The Gknomo-
rum ting ens of Ehrenberg (PL 31. fig. 14),
which consists of aggregated revolving
groups of green bodies, with two anterior
cilia, and a red (eye-) spot, has been shown
by Weise and Stein to form the young state
of CHLOROGONIUM, which itself appears
probably to be a stage of development of
PROTOCOCCUS.

GLENOPH'ORA, Ehr.— A genus of
Rotatoria, of the family Ichthydina.

Char. Free ; eyes two, frontal ; rotatory
organ circular and frontal; tail truncated,
without toes.

G. trochus (PL 43. fig. 36). Body ovato-

GLENOSPORA.

[ 358 ]

GLCEOCOCCUS.

conical, colourless, the turgid front and the
narrowed foot truncated ; eyes blackish ;
length 1-576" j freshwater.

BIBL. Ehrenb. In/us, p. 391.

GLENOS'PORA, Berk. & Desm.— A
genus of Dematiei (?) (Hyphomycetous
Fungi), of which one species (G. Thwaitesii)
appears to have been found in Britain.

BIBL. Berk. Hort. Journ. iv. p. 256.

GLOBIGERI'NA, D'Orb. — A typical
Foraminifer. The shell is minute and glo-
bose, consisting of a series of ten or fewer
globular chambers, arranged spirally in two
or three whorls, and increasing rapidly from
1-2000 to 1-80" in diameter. Surface
foraminated and rugose, sometimes prickly.
Each chamber opens into the umbilical
hollow by a crescentic orifice. In G. cre-
tacea and G. hirsuta the shell is almost dis-
coidal and nautiloid ; in G. buUoides (PI. 24.
tigs. 2, 3) the chambers become heaped ; in
G. helicina the later chambers expand and
grow irregular. In some cases the last
chamber overlaps all the others, and the
shell becomes an Orbulina.

G. bulloides is very abundant in the
Atlantic and other oceans, also in the
shallow water of the Adriatic. Many
varieties occur, recent and fossil, from the
Triassic period to the present day.

BIBL. Waffich,J?wfoy. £/o%.1876; Car-
penter, For. 181 ; Parker and Jones, Phil.
Tr. 1865, 365 ; Brady, Mic. Jn. 1879, 70.

GLOBULI'NA, Turp.=GLCEOCAPSA.

GLOBULI'NA, D'Orb. See POLYMOR-

PHINA.

GLCEOCAP'SA, Kiitz.— A genus of Pal-
mellaceae (Confervoid Algae), distinguished
by the rounded cells, single or grouped into
families, with special and general lamellar
envelopes. As we have adopted it, it is
distinguished from Palmella by the persis-
tence of the coats of the parent-cells as
envelopes enclosing their progeny of several
generations, to the number of 4, 16, 64, or
more secondary cells, the membranes becom-
ing confluent subsequently, however, by
solution, into a gelatinous mass. From
Coccochloris the chief distinction seems to
be in the persistence of the lamellae of the
parent cells in the membranous condition,
and the globular instead of cylindrical or
elliptical form of the cells, while the habit
is to form rather flat irregular strata than
.globose or papillose masses. From Proto-
coccus it is distinguished by the persistent
gelatinous investment. Some recent writers,
' especially Sachs, assume that the species of

Gloeocapsa are . early stages of development
of Lichens, from gonidia.

G. con/tuens. Stratum gelatinous, green.
Diam. of cell-contents, 1-1200 to 1-600'".=
H&matococcus minutissimus, Hassall ?

G. montana. Stratum gelatinous, green ;
vesicles concentrically striated; cell-contents
1-1000 to 1-500'" in diain. = .£f. nUcrosponut
Hass.

G. granosa. Stratum green, firm ; vesi-
cles concentrically striated ; cell-contents
1-300'" in diam. = //. granosus, Hass.

G. polydennatica (PI. 7 . fig. 4) . Stratum
hardish, olivaceous, somewhat compact or
granular ; concentric lamellae evident,
thick ; cell-contents 1-800 to 1-500'" in
diaui. = JST. rupestris, Hass.

G. eeruginosa. Stratum grey-aeruginous,
granular-crustaceous ; vesicleslarge (1-100
to 1-60'"), irregular; cell-contents 1-1000
to 1-600'". =//. ceruyinosus, Hass.

G. lividia. Stratum dirty olive or black-
ish, soft, but tubercular ; cell-contents aeru-
ginous; 1-700'". If. lividus, Has*.

G. Magma. Stratum purplish -black,
crustaceous, granular; cell-contents 1-600
to 1-320'". ISorospora mantana, Hass.

G. sanguinea. Stratum black ; internal
cells deep blood-red ; cell-contents 1-600 to
1-400'". = Hcematococcus sanguineus, Ag.,
Hass.

G. Shuttleivorthiana. Stratum dirty red ;
internal cells orange ; cell-contents 1-1000
to 1-900'".

G. Ralfsiana. Stratum dirty purple;
internal cells rosy-purple ; cell-contents
1-750 to 1-400'". S /Storapora Ralfsii, Hass.

In PI. 7. fig. 13 is represented a form we
have met with among freshwater Algae,
which appears to agree with Kutxing's
G. ampla.

Those resting forms of Euglena where the
encysted groups are devoid of a firm outer
coat, bear considerable resemblance to a
large Glceocapsa.

Rabenhorst describes 55 European species.

BIBL. Kiitzingr, Phyc. gen. 173, Sp. Alg.
216, Tab. Phyc. pis. 19 et seq.; Hassall, Alyee,
pi. 79, &c. ; Sachs, Bot. Zeit. xiii. 1 ; Al.
Braun, Rejuv. (Ray Soc. 1853), 131, 182;
Rabenhorst, Fl. Alg. ii. 34.

GLCEOCOC'CUS, Braun.— A genus of
Palmellaceae, consisting of active biciliated
gonidia resembling the moving form of
Protococcus, but connected into families by
a mass of soft jelly. See PALMELLACE.E.

BIBL. A. Braun, Verjiingung, 169 : Chy-
tridien, 57; Rabenhorst, FL Alg. iii. 36 (fig).

GLCEOCYSTIS.

[ 359 ]

GNETACE^.

GLCEOCYSTIS, Nageli= Glceocapsa, pt,

GL(EOSPO'RIUM,Montagne. — A genus
of Sphaeronemei (Stylosporous Fungi),
developed beneath the surface of leaves, and
bursting through, forming a kind of rust on
the surface.

G. paradoxum ( My xosporium paradoxum,
De Notar.) occurs on ivy.

G. Lobes. Asteroma Lobes, Berk. Brit.
Fungi.

G. concentricum (Cylindrosporum concen-
tricum, Grev. Sc. Crypt. Flor. p. 27) forms
a white rust upon cabbage-leaves.

BIBL. Berk. & Br. Ann. Nat. Hist. 2 ser.
V. p. 455 ; Berkeley, Hort. Trans, vi. p. 121.

GLCEOTHE'CA, Nag.— A genus of
Palmellaceae (Confervoid Algae), distin-
guished by the oblong or cylindrical cells,
with thick, often lamellar envelopes.

13 species ; on humid rocks (Rabenhorst,
Fl. Alg. ii. 60).

GLGEOTILA, Kiitz.— A genus of Con-
fervaceae with simple, submoniliform fila-
ments, endochrome of the cells becoming
contracted and rounded. Ten species.
Freshwater ; in ditches and aquaria. (Ra-
benhorst, Fl. Alg. iii. 319.)

GLOIOSIPHO'NIA, Carm.— A genus of
Cryptonemiaceee (Florideous Algae), the
single British representative of which is a
rare, feathery, red sea- weed, 3-12 inches
high, with a semigelatinous tubular frond.
The spores are in dense masses, scattered
among the radiating j ointed filaments which
clothe the periphery of the branches.

BIBL. Harvey, Mar. Alg. 152, pi. 21 A,
Eng. Sot. pi. 1219.

GLYCERINE is the sweet principle of
fats. It may be prepared by boiling fats
with oxide of lead and water. The aqueous
solutions are freed from the lead by sulphu-
retted hydrogen, the filtered liquid eva-
porated to the consistence of a syrup, and
finally in vacuo over sulphuric acid. It is
now procured by decomposing the fats with
high-pressure steam.

Glycerine, when pure, is a colourless,
highly refractive, syrupy liquid, of a sweet
taste j it mixes in all proportions with alco-
hol and water, but it is insoluble in ether.
The property possessed by glycerine, of
constituting a liquid which does not become
dry, and mixes with water, renders it very
useful for the preservation of microscopic
objects 5 especially those which will not
permit of being dried, such as preparations
of vegetable structure, which may De left on
a slide in a drop of glycerine, with a glass

cover to exclude dust, for weeks and months
without alteration. It renders objects very
transparent, which is sometimes advan-
tageous, sometimes the reverse. A solution
of gum-arabic in diluted glycerine is often
used for mounting objects which do not bear
drying. The solution is made by dissolving
1 oz. of very clear gum in 1 oz. of water, and
adding subsequently 1 oz. of glycerine:
great care must be taken, in incorporating
the glycerine, to avoid forming air-bubbles,
which are difficult to get rid of on account
of the viscidity of the fluid. The mode of
mounting objects is to soak them in pure
glycerine, and then to operate as with
Canada balsam, only not applying heat.
GL YCIPH' AGUS,Hering.— A subgenus

Of ACARTJS, p. 8.

GLY'PHIS, Ach.— A genus of Graphidei
(Lichenaceous Lichens).

G. labyrinthica, on trees, very rare.
(Leighton, Lich.-Flora, 436.)

GLYPHODES'MIS, Grev.— A genus of
Diatomacese.

Char. Fr. united into a filament ; side view
naviculoid, with a central nodule, median
line, and transverse rows of granules ; struc-
ture clathrate (?), the granules being deve-
loped within square areolae, arranged in
parallel rows.

G. eximia. In scrapings of marine shells.
Jamaica. .

BIBL. Greville, Qu,. Mic. Jn. 1862, 234
(figs.).

GLYPHODIS'CUS, Grev.— A genus of
Diatomaceae.

Char. Fr. four-sided, the angles much
rounded. Valves with a large 4-angled
nucleus, the angles alternating with those
of the margin; and a circular prominent
process within each marginal angle, from
which costae radiate to the nucleus ; whilo
similar costae radiate from the angles of the
nucleus to the sides of the disk.

G. stellatus. Monterey stone.

BIBL. Greville, Mic. Tr. 1862, 91.

GL YPHOMIT'RIUM, Bridel.— A genus
of Orthotrichaceous Mosses, deriving its
name from the grooved calyptra. Glypho-
mitrium Daviesii, Brid., is found in Wales
and Ireland on rocks, mostly near the sea.
It is peculiar to Great Britain and Ire-
land.

GNAT. See CTJLEX and CULICIB^E.

GNETA'CE^E.— An order of Flowering
Plants, remarkable for their jointed stems,
composed of ducts and wood-cells marked
like the wood of Conifers. The rind and

GOMPIIILLUS.

[ 360 ]

GONATOZYGON.

Fig. 283.

Glyphomitrium Daviesii.
Teeth of the peristome. Magnified 150 diams.

pith, also, contain curious branched liber-
cells.

GOMPHIL'LUS, Nyl.— A genus of
Lichenaceous Lichens.

G.calycioides. On mosses, rare. (Leigh-
ton, Lich.-Flora, 50.)

GOMPHOGRAM'M A, Braun.— A genus
of Diatomaceae, cohort Fragilarieae.

Char. Frustules solitary or geminate,
front view tabellar, with interrupted clavate
longitudinal vittae, ends internally dentate ;
valves ovate or elliptic-lanceolate, with
transverse continuous costae.

G. rupestre (PI. 52. fig. 3). On moist
rocks (freshwater).

BIBL. Rabenhorst, Fl. Alg. i. 116; and
p. 12 (fig.).

GOMPHONE'MA, Ag.— A genus of
Diatomaceae.

Char. Frustules mostly single or binate,
attached by a filiform stipes, wedge-shaped
in front view; valves with a median line and
a nodule at the centre and at each end, and
striated with transverse or slightly radiating
granular striae. Freshwater and fossil.

Conjugation has been observed in several
species.

Kiitzing describes thirty-eight species ;
Smith admits twelve as British. The form
of the frustule is subject to great variety ;
and the specific characters are probably of
little value.

The most common species are : —

G. acuminatum (PI. 16. fig. 34 a, 5, c).
Frustules in front view simply cuneate, or
inflated in the middle ; valves attenuated at
the base, ventricose in the middle, beyond
which they are again expanded ; ends acu-
minate, or truncate with an acuminate pro-
longation; striae distinct; length of frustules
1-360". San Fiore deposit.

G. geminatutn. Valves ventricose in the
middle, constricted and rotundo-truncate
towards each end ; striae distinct ; stalks

long, thick, densely interwoven ; length of
frustules 1-216 to 1-180".

G. olivacewn. Densely crowded, forming
a mucous mass ; frustules broadly cuneate
(fr. v.) ; valves obovato-lanceolate ; striae
distinct ; length of frustules 1-1020".

G. curvatum. Frustules curved ; valves
obovato-lanceolate ; striae faint ; length
1-720".

BIBL. Ehr. In/us. 215 ; Kutzing, Jiariff.
84, and Sp. Alg. 63 ; Smith, Br. Diatom.
76; Ralfs, Ann. N. H. 1843, xvi. 459.

GOMPHOSPILE'RIA, Ktz.— A genus
of Palmellacese ; with the cells radiating,
and united into groups in a globose mucous
envelope.

G. aponina. In pools. (Rabenhorst, Fl.
Alg. ii. 55.)

GONATOBO'TRYS,Corda.— A genus of
Mucedines (Hyphomycetous Fungi), the f er-

Fig. 284. Fig. 285.

Gonatobotrys simplex.

Fig. 284. A fertile filament. Magn. 100 diams.
Fig. 285. A sporiferous joint, with most of the
spores removed. Magn. 600 diams.

tile filaments of which present at intervals
swollen articulations, on which are attached
simple ovate spores (figs. 284, 285).

BIBL. Corda, Icones Fungorum.

GONATOR'RHODON, Corda. — A
genus of Mucedines (Hyphomycetous
Fungi), the fertile filaments of which have
at intervals swollen articulations, whence
arise moniliform chains of spores (fig. 286).

BIBL. Corda, Prachtfl. europ. Schimmelb.
pi. 3.

GONATOZY'GON, De Bary.-A genus
of Diatomaceae.

Char. Cells cylindrical or truncate-fusi-
form, neither constricted nor incised, united

GONGROSIRA.

[ 301 ]

GONIOI.

into long fragile Fig. 286.

filaments ; endo-
chrome simple, un-
dulate and twisted.
2 species ; fresh-
water.

G.Ralfsii(P\M.
fig. 37).

BIBL. Raben-
horst, Flor. Alg. iii.
p. loo.

GONGROSl'RA,
Ktz. — A genus of
Chaetophoraceae
(Conf ervoid Algae).

Gonatorrhodon speciosum.

Fertile filaments with swollen joints bearing chains of
spores. Magn. 100 diams.

Filaments jointed, sub-dichotomously
branched or tufted, attenuated at the base to
form a root-like thread; joints as long or
twice as long as broad, torulose. Four
species ; minute ; on stones, wood, and
aquatic plants. (Rabenhorst, Fl. Alg. iii.

GONID'IA.— The name applied to cells
which in the Thallophytes perform an office
analogous to that of the GEMMAE of the
higher Cryptogams, and the separating bud-
structures such as bulbils, stolons, &c. of the
Flowering Plants, — being cells developed
from the vegetative tissues, ultimately
thrown off, and capable of propagating the
individual. The gonidia of the Lichens are
globular cells with green contents, developed
in the central lay ers of the thallus, afterwards
set free by the destruction of the cortical
layer; they appear capable of multiplication
by subdivision before growing out into the
filaments which form the foundation of the
new thallus (see LICHENS). And the en-
dochrome has lately been observed in a few
Lichens to be resolved into zoospores, a cir-
cumstance which brings Lichens in an im-
portant point still nearer to Fungi. The
gonidia of the Fungi are usually termed
CONIDIA (see that article, and FUNGI}. The
gonidia of the Algae are best known in the
CONFEBVOIDS, where they are formed from
the cell-contents, and generally present
themselves ciliated, as ZOOSPORES. The
tetraspores of the Florideae are probably
the homologues of gonidia.

GONIO'COTES, Nitz. — A subgenus of
Philopterus, like Goniodes, but the antennae
alike in both sexes.

G. hologaster, on the fowl.

GONIOCY'PRIS, R & R.— A minute
Ostracode, with yellowish, compressed, trian-
gular valves ; found in the rivers and dykes
of Eastern England.

BIBL. Brady and Robertson, Ann. N. H.
1870, vi. 15.

GONIO'DES, Nitzsch.— A subgenus of
Philopterus (Anoplura), distinguished by
the large head, with projecting temporal
angles, no trabeculae ; antennae f orcipate in
the males, cylindrical in the females.
Several species, on the turkey, the guinea-
fowl, the domestic fowl, the pheasant, and
the grouse.

GONIOM'ONAS, St.— A genus of Fla-
gellate Infusoria.

Char. Free, or adherent posteriorly;
flagella two, equal, obliquely truncate in
front.

G.truncata. Freshwater. (Kent, Z??/.280.)

GONIONE'MA, Nyl.— A genus of Bys-
saceous Lichens.

G, velutinum. On subalpine rocks ; rare.
(Leighton, Lick. Fl. 9.)

GONIOTHE'CIUM, Ehr.— A genus of
fossil Diatornaceae.

Char. Frustules terete, with a median
(longitudinal) constriction (suddenly atte-
nuate and truncate at the ends, hence ap-
pearing angular).

Corresponds to Pyxidicula, constricted in
the middle, and truncate at the ends.

Found in America.

We have figured several of the nine or
ten species, some of which do not appear to
have the characters of the genus.

G. Anaidus (PI. 61. fig. 18) ; G. barbatum
(fig. 19) ; G. didymum (fig. 20) ; G. mono-
don (fig. 21); G. navicula (fig. 22); G.
Rogerm (fig. 23) ; G. gastridium (PI. 50,
fig. 40) ; G. odontella (fig. 44).

BIBL. Ehrenberg, Abh. Berl Ak. 1841,
401, Berl. Ber. 1844, 82, and Mikrogeol. ;
Kiitzing, Bacill. 51, and Sp. Alg. 23;
Greville, Mic. Tr. 1865, 56.

GO'NIUM, Miiller.— A genus of Volvo-
cineae (Confer void Algae), forming micro-
scopic, square, flat fronds, either ciliated and
endowed with a power of motion, or devoid
of cilia and motionless ; it is possible that
these two conditions are only stages of deve-
lopment in species active at one time and
resting at another. The perfect fronds are
composed of usually sixteen cells, enclosed
in wide colourless coats (young fronds but
four cells, some kinds have more than six-
teen) united together into flat square masses
by adherence at various points of their cir-

GONOTHYILEA.

[ 362 ]

GRAMMATONEMA.

cu inference. A light vacuole in the sub-
stance of the cell-contents may often be ob-
served to exhibit a rhythmical contraction
and expansion, as in rokoae. The cells of
the active forms have each a pair of vibratile
cilia, which run out from the central proto-
plasmic mass, through the hyaline envelope,
and project as free processes, rowing the
frond about in the water. They are com-
monly observed to increase by division, a
frond composed of sixteen cells breaking up
into four fronds, each composed of four cells,
&c. ; but it is probable that other kinds of
development exist, and that the motionless
forms are resting states of active species.
Goniumpectorale is an exceedingly interest-
ing microscopic object, not uncommon in
freshwater pools.

G.pectorale (PL 7. fig. 11). Frond square,
composed of sixteen bright-green cell-
masses enclosed in hyaline envelopes, each
with a pair of cilia ; size of green masses
1-1960 to 1-1150"; frond not exceeding
1-280". In clear water, salt and fresh,
near the surface.

G.punctatnm. Cells sixteen ; cell-masses
green, with black granules ; diam. 1-4600" ;
frond of sixteen, 1-576".

G. tranquillum (PI. 7. fig. 12). Cells
sixteen ; cell-masses green, diam. 1-2880" ;
frond of sixteen, 1-144 to 1-288", some-
times twice as broad as long ; the cell-masses
found in division (binate or quaternate),
motionless. (Possibly not a Gonium, but a
Palmellacean — Tetraspora ?).

G. hyalinum. Cell-masses hyaline, diam.
1-3000"; frond of twenty or twenty-five,
1-600". In stagnant water.

G. glaucum. Cell-masses bluish green,
from four to sixty-four in a frond, diam.
1-7000 to 1-4200", ditto of frond not ex-
ceeding 1-570". In sea-water.

BIBL. Ehrenberg, Inf. 55 ; Cohn, Nova
Acta, xxiv. 169, pi. 18 ; Fresenius, Mus.
Senckenb. GeseU. ii. 187, 1856.

GONOTHYR^E'A, Allman.— A genus
of Campanulariidse, Hydroid Zoophytes.
2 species.

G. Loveni (Laomedia dichotomy John-
son), on the fronds of the large sea-weeds,
and on stones, at low-water mark.

BIBL. Hincks, Hydroid Zooph. 180.

GOR'DIUS, Linn.— A genus of Nema-
toid Entozoa.

Char. Body very long and slender, fili-
form ; alimentary canal (none, Vill.) with a
single orifice, sexes distinct.

G. aquations, the common hair-worm, is

from 7 to 10" in length and about 1-25 to
1-20" in breadth, of a brown or blackish
colour, and is found in water or damp
places. The mouth is very indistinct ; the
tail of the male is bifid, that of the female
simple and rounded.

The ova, agglutinated in long strings, are
deposited in water, and being devoured by
insects or Arachnida, undergo development
within their bodies.

These animals frequently coil themselves
into a knot-like form, whence the name.
See MERMIS.

BIBL. Dujardin, Helminth. 296, and Ann.
So. Nat. 1842, xviii. 142 ; Ent. Zeit. 1842
-43, and Erichson's Archiv, 1843, ii. 302 ;
Berthold, Ban d. Wasserkalbes, 1842;
Meissner, Sieb. $ Koll. Zeits. 1856, i. ; Sie-
bold, ibid. 141; Grenadier, Sieb. $ Koll.
Zeitsch. 1868 ; Villot, Ann. N. H. 1872, x.
231 ; Cnmpt. Rend. 1880, 1569 ; Ann. N.H.
1880, vi. 169.

GORGO'NIA, Linn. — A genus of marine
Polypi, of the order Actinoida, and family
Gorgoniadae.

Char. Polypidom rooted, and consisting
of a central, branched, horny, and sometimes
anastomosing flexible axis, coated with a
soft and fleshy polypiferous crust.

The species are popularly known as sea-
fans; they are not microscopic, often attain-
ing very considerable dimensions.

The polypidom, as well as the crust, con-
tains spicula of various forms imbedded in
them, a specimen of which is exhibited in
PL 41. fig. 27.

BIBL. Johnston, Brit. Zooph. 166 ; Kent
(spicules), M. M. Jn. 1870, 76; Gosse, Acti-
nologia.

GOSSYPIUM. See COTTON.
GOUT-STONES. See CHALK-STONES.
GRACILA'RIA, Grev.— A genus of
Rhodymeniaceae (Florideous Algae), with
feathery fleshy-cartilaginous fronds, 3 to
12" or more long, of a red or purplish colour,
the central substance of which is composed
of large cells, the cortical of closely packed
horizontal filaments. The spores are formed
in tubercles consisting of a thick coat com-
posed of radiating filaments, containing a
mass of minute spores on a central placenta.
The tetraspores are imbedded in the cells of
the surface. G. confervuides is the only
common species; it grows from 3 to 20"
long, and as thick as small twine.

BIBL. Harvey, Br.Mar.Alg. 128, pi. 16C;
Engl. Boi. pi. 1668.
GRAMMATONEMA, Ag— A genus of

GRAMMATOPIIORA.

363 ]

GRANTIA.

microscopic marine plants, by some referred
to the Diatoinaceae, by others, including
Ralfs and Kiitzing, to the Desmidiaceae.

The recent observations of Smith show
that it belongs to the former family, and to
the genus Fragilaria.

G. striatulum=Fr. striatula.

GRAMMATOPH'ORA, Ehr.— A genus
of Diatoniaceae.

Char. Frustules in front view rectangular,
at first adnate, but afterwards forming zig-
zag chains ; vittso two, longitudinal, inter-
rupted in the middle and more or less curved.
Marine.

Valves linear or elliptical ; furnished with
transverse striae, in most, invisible by ordi-
nary illumination, and in a few so difficult of
detection that the valves have been regarded
as TEST OBJECTS. Sometimes a median
and terminal nodules are present.

Rabenhorst describes eleven species. Four
are British ; one doubtful : —

G. marina (PI. 1. fig. 14; PI. 16. fig. 35).
The markings or striae are invisible by ordi-
nary illumination 5 vittae near the middle
semicircularly curved outwards ; valves
linear or elliptical, gradually attenuated
towards the obtuse ends ; striae transverse ;
length 1-108 to 1-240".

The form and structure of the frustules
and valves appear greatly to vary. Some-
times the frustules are perfectly square, at
others six times as long as broad. In some
specimens the valves are suddenly, at others
uniformly inflated at the middle (PL 1.
fig. 146; PI. 16. fig. 35 c), some have the
ends capitate. Again, in some valves there
is a median line and a small central nodule
(PI. 16. fig. 35 c) ; in others there is neither
median line nor nodule, but a large internal
ring (PI. 1. fig. 14 6). Lastly, in some valves
the striae extend over the whole of the valves,
while in others they are deficient at their
ends. Some of these variations have formed
the basis of distinct species, but probably
with little reason.

A variety, G. siibtilissima, Bail. (PI. 1.
fig. 15 a, 6), has been pointed out by Prof.
Bailey, in which the form of the frustules
and valves agrees with the above characters,
but in which the transverse striae are ex-
tremely difficult of detection when mounted
in balsam.

G. macilenta. Fr. slender, often curved ;
vittae as in the last ; valves linear, slightly
inflated at middle and ends. Marine;
length 1-300".

G. serpentina. Vittae long, serpentine, with

the end curved inwards to form a kind of
hook; striae oblique. Marine; length 1-200".

G. ? Balfouriana. Vittae straight; valves
linear, inflated in the middle, and with
rounded ends. Freshwater.

BIBL. Ehrenberg, BerL Abh. 1839. 126,
and Ber. 1840, &c. ; Kiitzing, Sp. Aly. 120;
Bailey, Silliman's Journ. vii.; Smith, Br.
Diat. ii. 42 ; Schiff, Schultze's Archiv, iii.
81 ; Rabenhorst, FL Alg. i. 303 ; Petit, Jn.
Mic. Soc. 1881, i. 109.

GRAMMITID'EJE.— A family of Poly-
podiaceous Ferns.

Char. Son on the back of the fronds,
more than twice as long as broad, usually
linear. Genera :

Jamesonia. Sori oblong, on the flabellate
veins of the back of the pinnae, not reaching
the margin.

Brainea. Sori continuous along trans-
verse veins near the midrib, also produced
along the veins towards the edge of the
frond.

Notochl&na. Sori marginal, oblong or
rounded, then confluent into a marginal line,
the edge of the frond frequently inflexed to
form an involucre ; veins free.

Monogramma. Sori linear, close to the
midrib on one or both sides.

Gymnogramma. Sori on the veins of tho
under surface of the frond, linear, simple or
forked.

Meniscium. Sori oblong or linear, occu-
pying the connivent transverse veinlets of
the simple or once pinnate fronds.

Antrophyum. Sori on the veins, imper-
fectly reticulated.

Vittaria. Sori in continuous marginal or
slightly intramarginal lines.

Tcenitis. Sori linear, the line sometimes
interrupted, central or submarginal.

Drymoglossum. Like Tanitis, bat the
fronds dimorphous.

Hemionitis. Sori continuous along the
veins, and copiously reticulated, sometimes
also slightly developed between them.

GRAMMI'TIS, Swartz., is merged into
Polypodium and Gymnogramma. Ceterach
is sometimes taken for a Grammitis.

GRAMMONE'MA, Ag. = GRAMMATO-

NEMA.

GRAN'TIA, Fleming. — A genus of
Sponges.

Char. Form variable; firmish and in-
elastic, usually white, with a close but po-
rous texture, and composed of a gelatinous
base, with imbedded calcareous spicula; ori-
fices distinct. Marine.

GRANULE-CELLS.

[ 364 ]

GREGARINA.

Spicula simple, radiate or stellate, com-
posed of carbonate of lime ; hence easily
distinguished from the siliceous spicula of
other sponges by their dissolving with effer-
vescence in a dilute acid. The organic basis
is stated not to be fibrous as in most other
sponges.

The British species are found growing
upon or from rocks, sea-weeds, shell-fish
and zoophytes, between tide-marks. They
vary in size from about the 1-10 to 3 or 4".
Gemmules have not been found.

BIBL. Johnston, Br. Sponges, 172; Grant,
Compar. Anat. and New Phil. Jburn. i. and
ii. ; Bowerbank, Br. Spong. ii. 1.

GRANULE-CELLS.— This term has
been applied to cells fonnd in animal solids
and liquids containing a number of globules
of fat or oil (PL 38. figs. 7, 16 a, 17 e). They
are of variable size, perhaps the average
may be placed at 1-2000" ; and are easily
recognized by the dark margins and light
centres of the globules, which are insoluble
in acetic acid and solution of potash. The
cells sometimes contain a nucleus, at others
not. The term granule-cells should pro-
perly be limited to cells of new formation,
as those found in inflammation, cancer, &c. ;
but it has been so generally applied to cells
of whatever kind, containing fatty globules,
that it has no pathological signification.

See DEGENERATION, FATTY, and INFLAM-
MATION.

GRANULOSE. See STARCH.

GRAPE-FUNGUS. See OIDIUM.

G RAPHID 'El.— A tribe of Lichenaceous
Lichens, having a thin, crustaceous, scarcely
visible or subepidermal thallus, with lirel-
line apothecia.

It includes the British genera : Agyrium,
Arthonia, Chiodecton, Glyphis, Graphis,
Lithoyrapha, Melaspilea, Opegrapha, Platy-
grapha, Ptychographa, Stigmatidium, and
Xylographa.

BIBL. Leighton, Brit. Lichen-Flora, 390.

GRA'PHIS, Ach.— A genus of Graphi-
dei, containing ten British species, very va-
riable in their appearance ; mostly whitish
or yellow papery expansions on the bark of
trees, beset with irregular black markings
(lirelline apothecia) like writing.

BIBL. Leighton, Brit. Lich.-Fl 426.

GRASSES.— A family of Monocotyledo-
nous Flowering Plants, remarkable in many
respects for their microscopic structure,
especially the siliceous EPIDERMIS and the
STARCH grains in the ALBUMEN, for which
see those heads.

GRATELOU'PIA, Ag.— A genus of
Cryptonemiaceas (Florideous Algae), repre-
sented by a very rare British species, G.fli-
cina, seldom growing more than 2 inches
high with us. Fructification minute, im-
mersed, favellidia opening by a pore, and
cruciate, tetraspores vertically placed among
the filaments of the periphery.

BIBL. Harv. Mar. Alg. 137, pi. 17 A;
Grev. Alg. Brit. pi. 16.

GREENSAND.— According to the ob-
servations of Ehrenberg and Bailey, the
glauconitic grains frequent in many geolo-
gical deposits, especially in certain beds
known as Greensaud, are formed of foasilizod
organic bodies, mostly casts of Foramini-
fera.

BIBL. Ehrenberg, Abh. Berl Akad. 1856,
85-176; Monatsber. 1858, 328; Bailey, Ann.
N. H. s. 2. xviii. 425; Parker & Jones, Ann.
N. H. s. 4. x. 263 ; Sollas, Geol. Mag. 1876,
539.

GREGARFNA, Dufour.— This curious
group of organisms, which was formerly
placed among the Entozoa, is now placed
among the Protozoa, forming the Order
Gregarinida ; but there are still doubts as
to their structure and nature.

They exist as parasites within the bodies
of animals, and often inhabit the intestinal
canal, or the cavity of the abdomen. Most
frequently they are met with in insects,
especially their larvae ; but sometimes also
in Annelida, both freshwater and marine
(Lumbricus &c.), in the Crustacea and Mol-
lusca ; and even in human organs.

They are mostly microscopic, and colour-
less ; round, oval, fusiform, or cylindrical
(PL 21. figs. 25, 28, 34) ; and consist of a
smooth transparent cell-wall, enclosing a
granular, more or less liquid mass, with one
or more nuclei or nucleoli. Sometimes
they exhibit a constriction in the middle,
or are divided by a transverse septum. In
some a process resembling a head is situated
at one end ; this may be short, round, and
obtuse or pointed, or more elongated and
furnished with reflexed hook-like processes.
The GregarincB are capable of motion, which
is either that of slow progression, ensuing
without contraction of the body, or pro-
duced by irregular contraction of the mem-
brane or substance of the body.

Vibratiie cilia have been detected both
upon the outer and the inner surface of the
membrane ; and the internal granules often
exhibit molecular motion, especially after
the addition of water. One or more long

GRIFFITHSIA.

[ 365 ]

GRIMMIA.

motionless filaments sometimes arise from
the outer surface.

The membrane and its contents, except
the nucleus, are soluble in acetic acid.

Their method of propagation, if such it
is, represents a form of conjugation, and
takes place as follows. Two individuals
coming into contact by corresponding por-
tions of the body (PL 21. fig. 34), become
shortened and firmly united. A transparent
capsule is next formed around them, which
encloses them in a cyst (figs. 26, 30), the
adjacent portions of the cell-membranes are
absorbed, and the substance of the two
bodies become intimately fused. Globules
or cells are then formed in the contents of
the cell, which subsequently assume the
form of Navicula, and have been called
pseudo-naviculee (erroneously navicellce :
figs. 31, 32, 33); these burst, producing
Amcebiform bodies, which develop into new
Gregarince.

It was supposed that the pseudo-naviculae
were really Naviculce, and that the cysts con-
taining them were sporangia j but the pseu-
do-naviculse do not possess a coat of silex.

In some cases it appears that the con-
tents of the two cells in conjugation remain
distinct until the pseudo-naviculse are
formed ; but it is not certain whether each
single cell in these instances has not arisen
from the fusion of two others.

A very large number of species of Gre-
garina have been described and arranged in
numerous genera.

BIBL. Dufour, Ann. Sc. Nat. 1837, vii. ;
Stein, Mutter's Arch. 1848 ; Ann. N. H.
1850, v.. and Infus. ; Frantzius, Gre.qar.
1846 ; Henle, Mutter's Archiv, 1835, 1845 j
Siebold, Naturg. d. wirbellos. Thiere, 1839 ;
Kolliker, Sieb. 8? Kottiker's Zeitschr. 1848
& 1849; Ray Lankester, Qii. Mic. Jn.
1863, iii. 83, and Mic. Tr. 1866, 23 (PI.) ;
V. Beneden (G. of lobster), Butt. I'Acad. d.
la Selgique, 1869 (M. M. J. 1870, 47), and
Ann. N. H. 1872, x. 309.

GRIFFITH'SIA, Ag.— A genus of Cera-
miaceae (Florideous Algae), with feathery
fronds 3 to 6" long, composed of delicate
dichotompusly-branched filaments consist-
ing of a single row of cells, the branchlets
often whorled ; colour crimson or rosy-red.
The fructification consists of spores, anthe-
ridia, and tetraspores, all produced in simi-
lar situations, namely at the articulations,
where they are surrounded by a kind of
involucre formed of short ramelli, to which
the tetraspores and antheridia are attached.

The antheridia consist of a kind of shrubby
tuft of extremely minute filaments arising
from an axial filament which arises from a
ramellus of the involucre. Fig. 287 repre-
sents a branch terminating in an involucre
of whorled ramelli bearing tetraspores ; the
lower figure is a portion of a ramellus

Fig. 287.

Griffithsia sphaerica.

Fig. 287. Fragment of a frond bearing an involucre with
tetraspores. Magn. 50 diams.

Detached ramellus of the involucre, showing the at-
tachment of the tetraspores. Magn. 40 diams.

showing the mode of attachment of the te-
traspores. In the antheridial involucres, the
plumose antheridial structure is attached in
exactly the same way. Seven British spe-
cies are recorded, of which one or two are
not uncommon.

BIBL. Harvey, Mar. Alg. 167, pi. 23 B ;
Decaisne, Ann. Sc. Nat. 2 ser. xvii. p. 353,
pi. 16 ; Thuret, Ann. Sc. Nat. 3rd ser. xvi.
16, pi. 5 ; Derbes and Solier, ibid. xiv. 276,
pi. 36 ; Engl. Sot. pi. 1479 & 1689.

GRIM'MIA, Ehrhart.— A. genus of Or-
thotrichaceous Mosses, containing numerous
British species.

Fig. 288.

Grimmia.
Teeth of peristome. Magnified 150 diameters.

Many of the species of Trichostomum of

GROMIA.

[ 366 ]

GUTTA-PERCHA.

Hedwig and Schwaegrichen are placed here
bv Bruch and Schimper and C. Miiller.

" BIBL. Wilson, Bryol Brit. 152 j Berke-
ley, Handb. 237.

GRO'MIA, Duj. — A genus of Rhizopoda,
of the order Reticularia.

Char. Carapace brownish yellow, mem-
branous, soft, globular or oval, with a small
round orifice, from which very long, fili-
form branched expansions with very deli-
cate extremities protrude ; the presence of
a nucleus and contractile vesicle is doubtful,
or variable.

G. oviformis. Carapace globular, with a
short neck; marine; size 1-25 to 1-12";
among marine plants.

G.flumatilis (PI. 31. fig. 15). Carapace
globular or ovoid, without a neck ; fresh-
water; breadth 1-280 to 1-100". Found
upon Ceratophyllum.

Schlumberger describes a freshwater
Gromia (hyalina), differing from the last in
size (1-860 to 1-520''), and in the carapace
being colourless, perhaps the young state of
G.flumatilis. Schultze describes some new
marine species : G. oviformis, G. Dujar-
dinii, and G.paludosa-, G. terricola (Leidy)
is cream-coloured, and occurs in earth be-
tween paving-stones.

BIBL. Dujardin, Ann, Sc. Nat. 1835,
iv., Infus. p. 252 ; Schlumberger, Ann. Sc.
Nat. 1845, iii. 255 ; Schultze, Polytkal. 55;
Cienkowski, Schnitzels Arch. 1876, xii. 32 ;
Claparede and Lachm. Inf. 465 ; Leidy,
Sitt. Am. Jn. 1875 (M. M. Jn. xiii. 87).

GROWING-SLIDE.— Several modifi-
cations of this apparatus (Introd. p. xxiii)
have been recently described.

See Smith, Ann. N. H. 1865, xvii. 334 ;
Barker, Qu. M. Jn. 1866, 267; R. Beck,
Mic. Tr. 1866, 34; Miiller, M. M. Jn. i.
1869, 174 ; Maddox, M. M. Jn. 1870, iii.
14 ; Broeck, M. M. Jn, 1876, xv. 221 ;
Lewis and Cunningham, ibid. 198 ; Jn. Mic.
Soc. 1880, 333 ; Beale, How $c. 76 ; Bot-
terill, Jn. Mic. Soc. xix. 34 ; Dallinger,
M. Mic. Jn. 1874, xi. 97.

GUANO. — As is well known, guano is
imported into this country in large quanti-
ties as a manure. It consists principally of
the excrement of birds, in a more or less
decomposed state. It affords the micro-
scopist a means of procuring many foreign
marine Diatomaceae, the frustules and valves
of which are often contained in it in large
numbers. The Diatomaceae may be obtained
from guano as recommended ait page 250.

GUEMBE'LIA, Hmp.— A genus of Or-

thotrichaceous Mosses, including various
species separated from Grimmia on account
of the peculiar calyptra, also the CincUdoti
of P. Beauvais.

G. orbicularis, Hmpe.= 6rnmmtVz orbicu-
laris, Br. Eur.

G. riparia = Cinclidotus riparim, Wils.

Fig. 289. Fig. 290. Fig. 291.

Guembelia fontinaloides.

Fig. 289. A fertile shoot.

Fig. 290. Capsule with calyptra. Magn. 10 diams.

Fig. 291. Teeth from the peristome. Magn. 150 diams.

G. fontinaloides (figs. 289-91)= Cincl
fontinaloides j P. B.

BIBL. Wilson, Bryol. Brit. p. 139.

GUM. — A name applied to various viscid '
(not oily) secretions of plants. Gums have
no microscopic structure when pure and
clean, but often exhibit under the micro-
scope traces of structures, such as debris of
cellular tissue, filamentous Fungi, &c.,
which have become imbedded in them
while soft. What is called gum Traga-
canth consists of partly decomposed cell-
membranes, in a condition allied to amy-
loid, retaining traces of their organization.
Sections of very soft tissues or very minute
objects may be made by imbuing them with
or immersing them in solution of gum, and
allowing the whole to dry up to a tough,
semisolid mass, capable of being sliced with
a razor. The slices are freed from gum by
soaking in water. Gum dissolved in GLY-
CERINE forms an excellent medium for
mounting vegetable tissues.

GUTTA-PERCHA.— A substance pro-
duced by the evaporation of the milky juice
of the "isonandra gutta, of the Natural
Order Sapotacese, a native of Sumatra
and the neighbouring regions. Its relation
to the microscope arises from its use in a

GUTTULINA.

[ 367 ]

GYRINUS.

solid form and as cement, in mounting
microscopic objects in cells. See CEMENTS
and PREPARATION.

GUTTULINA. See POLYMORPHINA.

GY'GES, Bory.— Described by Ehren-
berg as a genus of Volvocineae, having
neither eye-spot, tail, nor flagelliform fila-
ment ; the carapace (cell-membrane) simple,
subglobose j freshwater.

Motion very slow. He gives two spe-
cies:

G. granulum (PI. 50. fig. 14). Ovate or
subglobose; internal granular mass dark
green ; diam. 1-1150".

G. bipartitus. Nearly spherical ; internal
mass yellowish green, frequently bipartite ;
diam.' 1-480".

So far as appears from the descriptions
and figures, these do not seem to differ
from PROTOCOCCUS.

(For G. sanyuinea, Shuttleworth, see
RED SNOW.)

BIBL. Ehr. Infu8. p. 51.

GYMNOAS'CUS, Bar.— A very minute
and simple form of Ascomycetous Fungi ;
found on horse- and sheep's dung. (Bara-
netzki, Bot. Zeit. 1872; Sachs, Sot. 310;
Eidam, Cohris Beit. iii. 267 ; Jn. Mic. Soc.
1881, 489). See ASCOMYCES.

GYMNODINTUM, Stein.— A genus of
Cilio-flagellate Infiisori&= Peridinia with-
out a lorica.

7 species ; in fresh and salt-water (Kent,
In/us. 442).

G YMNOGON 'GRUS, Mart.— A genus of
Cryptonemiaceae (Florideous Algae), with
horny branched fronds, the divisions cylin-
drical or compressed, a few inches high, of
a purplish-red colour. The substance of the
branches presents three layers of closely
packed filamentous cells, the central lon-
gitudinal, the intermediate curved, and the
peripherical horizontal and moniliform.
The spores have not been observed; the
tetraspores (cruciate) are arranged in mo-
niliform rows, in wart-like thickenings of
the branches.

BIBL. Harvey, Mar. Alg. 145, pi. 18B;
Engl. Bot. pi. 1089 & 1926.

GYMNOGRAMMA, Desv.— A genus
of Grammitidese (Polypodiaceous Ferns),
some of the species of which are remarkable
for a yellow or white pulverulent appear-
ance on the back of the fronds, owing to
the presence of abundance of microscopic
cellular hairs, ex. gr. G. Calomelanos, G.
chrysophylla, ochracea, &c. Many species,
mostly tropical. (Hooker, Syn. Fil. 376.)

GYMNOMIT'RIUM, Corda.— A genus
of Jungermaunieae (Hepaticae), containing
one British alpine species, the Jungerman-
nia concinnata of the British Flora.

BIBL. Hook. Brit. Jung. pi. 3; Ekart,
Syn. Jung. pi. 8. fig. 63; Engl. Bot. pi.
1022.

GYM'NOPHRYS, Cienk.— A genus of
Reticularian Rhizopoda.

Char. Body naked, without nucleus or
contractile vesicles. The pseudopodial re-
ticulations, which exhibit the granular
currents, arise from a few variable points of
the surface.

G. cometa. In marine and boggy pools,
among algae. (Cienkowski, Schnitzels Arch.
1876, xii. 31.)

GYMNOSPER'MIA.— A division of the
Flowering Plants (see VEGETABLE KING-
DOM), including the CONIFERS and CYCA-
DACE^ ; deriving this name from the mode
of development of the OVULES.

GYMNOSPORAN'GIUM, B.C.— A ge-
nus of Uredinei (Hypodermous Fungi). G.
juniperinum grows upon living branches
of the common Juniper, appearing at first
like an exanthema on the bark, which in wet
weather swells up into an orange-coloured,
tremelloid plicate mass, which readily dries
up, however, and then is scarcely visible.
Somewhat rare, but when present generally
copious.

BIBL. Berk. Br. Fl. vi. part 2. 361 ;
Fries, Syst. Myc. iii. 505 ; Tulasne, Ann.
Sc. Nat. 4 se>. ii. 171 & 188.

GYMNOSPO'RIUM, Corda.— A genus
of Torulacei (Coniomycetous Fungi), cha-
racterized by an obscure mycelium and
unicellular black spores arising apparently
from the matrix. It is the lowest condi-
tion of which Torulacei are capable.

G. arundinis occurs in this country on
reeds. '

BIBL. Corda. Anleitutig, 10 ; Berk. Outl.
328.

GYMNOSTOMUM, Schwagr.— A ge-
nus of Mosses now distributed into PY-
RAMIDIUM, PHYSCOMITRIUM, and other
genera.

BIBL. Miiller, Syn. Muse. ; Bruch and
Schimper, Bryol. Eur. ; Wilson, Bryol. Br.
39 ; Berkeley, Handb. 237.

GYPSI'NA, Carter. See TINOPORUS.

G YRI'NUS, Geoflr.— A genus of Coleo-
pterous insects, of the family Gyrinidae.

G. natator, one of the eight British spe-
cies of this genus, is very commonly seen in
groups performing its gyrations upon the

GYRINUS.

[ 368 J

GYBOSIGMA.

surface of pools or rivers, whence it lias
received the popular name of whirligig.

The body is ovate or elliptic, and de-
pressed, the elytra black and shining. The
antennae are short and retractile within a
cavity in front of the eyes; the basal joint
minute ; the second large, globular, and fur-
nished externally with an ear-like joint
fringed with colourless, flattened, hair-like
processes ; the remaining seven joints form
a clavate mass, being very short and closely
united, the h'rst commencing by a very
narrow base or pedicle. The eyes are di-
vided by a transverse septum into two parts,
the upper of which serves for viewing ob-
jects in the air, the latter those in water ;
by some authors these insects are described
as possessing four distinct eyes. The ter-
minal segment of the abdomen is furnished
with two retractile ciliated lobes. The two
fore legs are long, and of the ordinary form,
whilst the four hind legs (PI. 34. fig. 5),
which are used as oars, are short, flat, and
dilated ; the femur (d) and tibia (c) some-
what triangular, the tibia also fringed with
short spines and long flattened filaments ;
in the middle pair of legs the latter exist
on both margins, whilst in the hind legs
these are present only on the outer mar-
gin. The tarsi (a) are five-jointed, the
three basal joints produced on the inside
into long, flat, leaf-like lobes fringed with
spines ; the fourth joint is of about the same
size, and semicircular, the fifth being very
short and attached to the fourth near the
end, and both are fringed on their outer
margin with flattened filaments resembling
those upon the tibia ; all the tarsi are fur-
nished with two distinct claws.

The anterior tarsi of the male differ from
those of the female, as in Dytiscus. The
circulating currents can be seen in the hind
legs.

The larva (PI. 35. fig.19), which is aquatic,
is of a dirty-white colour, long, narrow, and
depressed, resembling a small centipede j it
consists of thirteen segments including the
head. Its antennae are filiform and four-
jointed ; the eyes numerous and tubercular,
grouped on each side of the head. The
three pairs of legs are attached to the eight
anterior segments of the body ; the remain-
ing segments are furnished on each side
with a branchial filament, excepting the
last, which has two of them, and four mi-
nute conical points, bent downwards, and
used by the insect when in motion.

BIBL. Westwood, Introd. i. 105; Ste-
phens, Br. Coleop. 78.

GYROC'ORIS, St.— A genus of Peri-
trichous Infusoria.

Char. Free, with one or more spiral or
circular wreaths of cilia, stylate poste-
riorly.

G. oxyura. With anterior eye-spot j mo-
tion revolving, rapid. Stagnant water.
(Kent, Inf. (340.)

GYRODAC'TYLUS, Nordm.— Agenus
of Trematode Entozoa.

G. auriculatns (PI. 21. fig. 7) is often
found adhering to the gills of fishes, as the
carp, stickleback, &c.

BIBL. Dujardin, Helminth. 480; Wa-
gener, Qu. M. Jn. 1801, 196; Cobbold,
Paras. 465.

GYROPH'ORA, Ach.— A genus of
Phylloidei (Lichenaceous Lichens), com-
bined with Umbilicaria by many authors.

GYROPOREL'LA, GiimbeL-A small
cylindrical Foraminifer, belonging to the
Dactyloporina, and consisting of ring-like
segments traversed by simple canals. Its
several species constitute large masses of
Triassic limestone in the Alps.

BIBL. Giimbel, Abh. Munchen, xi. 268.

GYR'OPUS, Nitzsch.— A genus of man-
dibulate Anoplura (Insects), of the family
Liotheidse.

Char. Tarsi two-jointed, with a single
claw.

Mandibles without teeth ; maxillary palpi
conical and four-jointed; labial palpi none;
antennae four-jointed; thorax two-jointed;
abdomen eight-jointed.

G. ovalis (PI. 35. fig. 8). Head ferrugi-
nous, transverse, with a lateral produced
lobe on each side ; thorax and legs ferrugi-
nous; abdomen nearly orbicular, yellow-
ish white ; claws long, curved, and strong ;
length 1-48"; found on the guineapig
(Cavia cobaya).

G. gracilis. Head and thorax ferruginous;
abdomen elongate, segments with a trans-
verse striated band at each suture ; claws
very short and minute; length 1-36"; also
on the guineapig.

3 other species : on the agouti, the sloth,
and the peccary.

BIBL. Denny, Anoplur.Monoyr. ; Megnin,
Paras. 94.
GYROSIG'MA, Hass. See PLEURO-

SIGMA.

H.EMALASTOR.
H.

[ 369 ]

ILEMATOPINUS.

H^EMALAS'TOR, Koch.— A genus o:
Ixodea (Acarina) ; with the body of male
entirely covered by a shield, yellow or red
no emargination in front; eyes clear anc
conical. Two species; on bats &c., Brazil
and Hungary. (Murray, EC. Ent. 198, figs.)
ILEMAPHY'SALIS, Koch.— A genus
of Ixodea (Acarina) ; with the palpi very
small, almost broader than long, three-
cornered, the posterior margin of the second
joint expanded outwards.

H. rosea. West Indies (Murray, EC. Ent.
200, fig.).

H^E'M ATINE.— The red colouring-mat-
ter of the blood, in the globules of which it
exists combined with globuline. It pos-
sesses no morphological characters*
BIBL. See CHEMISTRY.
ILEMATOCOC'CUS. See PHOTO coc-
cus and GLCEOCAPSA.

HJEMATO'IDINE.— This substance, to
which Virchow first drew attention, is not
unfrequently met with in masses of extra va-
sated blood which have remained for some
time in the living bodies of the Vertebrata,
as in old apoplectic clots, sanguineous ex-
travasations resulting from contusions and
wounds, the effusions accompanying the
rupture of the Graafian vesicles, &c.

It occurs in the form of granules, globules,
and distinct crystals. These are somewhat
highly refractive, and mostly of a ruby-red
or yellowish-red colour; they are stated also
to have been found colourless. The most
common forms are represented in PI. 13.
fig. 16, and they appear to belong to two
distinct systems — the oblique rhombic pris-
matic, and the regular system.

The properties of haematoidine are as
inconstant as the crystalline form ; and it is
probable that several different substances
have been ranged under the above title, or
perhaps modifications of the same substance
in different states of hydration ; for so insu-
perable has been the difficulty of obtain-
ing haematoidine in quantity and a state of
purity, that its true nature has not been
satisfactorily determined. By some it is
considered as bilirubine, or a modification
of it.

It is mostly insoluble or difficultly soluble
in water, alcohol, ether, acetic and dilute
mineral acids, and solution of potash. Some-
times it is soluble in acetic acid, with a
yellow colour, at others readily so in water.
It contains no iron.

An amorphous colourless proteine sub-
stance is sometimes separated from the crys-
tals by the action of mineral acids.

Haeinatoidine maybe artificially procured
from various sources, perhaps most readily
from the blood of fishes by spontaneous
evaporation. The blood of the spleen of the
horse changes almost entirely into prismatic
crystals of it in drying. In obtaining the
crystals the presence of the serum is preju-
dicial, and it should be washed away with
a small quantity of water. If recently dried
blood be treated with a vegetable acid
(acetic, oxalic acid, &c.), and a drop of the
solution be placed upon a slide, covered with
thin glass, and kept at a temperature of 80°
to 100° F., the crystals may also be obtained.
This reaction might be of use in judicial
investigations. The addition of water and
a little alcohol or ether to the blood,
sometimes favours the separation of the
crystals.

Crystals of hsematoidine (?) have been
found within the blood-globules prior to
the addition of reagents.

Their preservation is difficult ; it is best
effected by washing them with alcohol, or
this liquid somewhat dilated with water,
and drying them under the air-pump, or
over sulphuric acid.

BIBL. VTirchow, Ann. Chem. u. Pharm.
1851 (Chem. Gaz. 1852) ; Funke, Zeitsch.
f. rat. Med. 1851, i. 172, 1852, ii. 199 &
288 ; Kunde, ibid. 1852, ii. 271 ; Lehmann,
Gmelirfs Handb. viii. ; Sanderson, Edinb.
Mn. Jn. xiii. 216, 521 ; Kolliker, Mik. An.-,
Teichmann, Zeits. f. rat. Med. 1853, iii.
375; Erey, Histol. 1876; Preyer, Blut-
Krystalle ; Hoppe-Seyler, Anal. Chim.
1877, 242.

ILEMATOPl'NUS, Leach.— A genus of
Insects, of the order Anoplura, and family
Pediculidae.

Char. Legs all formed for climbing ; tho-
rax generally narrower than the abdomen,
and distinctly separated from it ; abdomen
composed of eight or nine segments.

This genus contains several species (28
Megn.), which live as parasites upon various
animals — the field-mouse, rat, dog, ox,
horse, ass, calf, hog, rabbit, hare, squirrel,
&c.

H. mis (PI. 35. fig. 4; fig. 4*, anterior
leg). Dusky ferruginous ; abdomen grey or
ashy-yellow, flat and membranaceous, with
a black horny excrescence surrounding each
of the white spiracles ; legs long and thick ;
femur transversely striped ; tibiae very ab-

2B

ELEMATOPOTA.

[ 370 ]

HAIR.

ruptly clavate, dark-coloured at the end ;
tarsi with a large fleshy pulvillus.

Found upon pigs out of condition ; length
1-10 to 1-6",

BIBL. Denny, Anopl. Brit. 24 ; Gervais,
Walckenaers Apteres, iii. 301; Megnin,
Paras. 76.

H^EMATOPO'TA, Meig.— A genus of
Dipterous Insects, of the family Taba-
nidse.

Distinguished by the six- jointed antennae,
which are longer than the head, with the
third joint thickened at the base.

H. 'pluvialis, of which most persons must
have experienced the pungent bite in or
near woods in warm weather, is interesting
on account of the great development of the
lancets, and the beautiful iridescence of the
eyes.

H^EM ATOZO' A . See BLOOD, p. 105, &
FILABIA, p. 324.

K^E'MLNE. — This consists of hydro-
chlorate of haematine.

ILEMO'CHARIS, Sav. (Piscicola,
Blainv.). — A genus of Annulata.

H.piscium {Piscicola geometra} is a leech-
like animal, found upon the carp, tench,
roach, &c. Length 1 to 2".

BIBL. Leo, Mullers Arch. 1835 ; Leydig,
Siebold und Kolliker's Zeitschr. i. ; Bright-
well, Ann. N. H. 1842, ix. 11.

ILEMOGLO'BINE. See BLOOD, p. 102.

ELE'MOPIS, Sav. — A genus of Annu-
lata.

H. sanguisorba, the common horse-leech.
In this animal the teeth are less numerous
and more obtuse than in the medicinal
leech (Hirudo officinalis).

HAIL. — The microscopic structure of
hail-stones does not appear to be uniform.
In some a central nucleus surrounded by
concentric layers has been noticed ; in others
the nucleus is enveloped by a radiating crys-
talline crust ; or, again, the entire mass has
been found to consist of little spheres of ice.
When hail-stones liquefy, a copious evolu-
tion of gas takes place. Hail-stones may
best be collected for examination in a
blanket, which being a bad conductor of
heat, retains them longest in the solid state.
Connected with the structure and formation
of hail-stones, is the composition of spherules
of condensed vapour. These are generally
believed to consist of films of water enclos-
ing portions of air; butWaller's observations
have led him to the conclusion that they are
simply composed of water. If the former
view 'were correct, those hail- stones which

consist of aggregations of icy spherules,
should contain air within them, which does
not appear to be the case ; but in deciding
this question, attention must be paid to the
principles laid down in the INTRODUCTION,
p. xxxvi, /., which afford a simple means
of deciding the point.

In some liquefied hail-stones, the spores
of fungi and algae, with infusoria, have
been found.

BIBL. Pouillet, Elem. d. Physique, ii. ;
Waller, Phil. Tr. 1847, 23; id. Phil. Mag.
1846, xxix. 103, and 1847, xxx. 159 ; Hart-
ing, Skiz. aus d. Natur.

HAIR OF ANIMALS. — The structure of
the hair of animals is very complicated, and
requires careful manipulation for its investi-
gation. We shall commence with the hair
of man, in which it has been the most per-
fectly examined.

Human hair. When a hair is viewed
under a low power, it appears black at the
sides and light in the middle, so as to convey
a notion of its being a tube ; such is not,
however, the case, although this notion was
long admitted.

The hairs are secreted by the skin, and
consist of modified epidermic formations.
Each is implanted in a cutaneous depres-
sion, termed the hair-follicle (fig. 292), at
the bottom of which it is fixed by a dilata-
tion called the knob or bulb of the hair (c).
The free portion, or that projecting beyond
the skin, is the shaft or scape (a) ; and that
above the bulb but contained within the
follicle, is the root (6). The bulb encloses
or surrounds a conical or rounded body (*'),
the papilla or pulp.

Three varieties of hair are met with upon
different parts of the body: 1, consisting of
long, soft hairs, from 1 to 3" and more in
length, as the hair of the head ; 2, short,
rigid and thicker hairs, from 1-4 to 1-2" in
length, as in the eye-lashes ; and 3, short,
very slender hairs, from 1-12 to 1-6" in
length, as in the down or woolly hairs of
the face, the back and extremities.

When the shaft of a hair is examined
under the microscope by transmitted light,
two structures are mostly distinguishable,
a median, more or less black, somewhat
irregularly granular and linear portion — the
medulla or pith; and an outer, fibrous-
looking portion, mostly more or less co-
loured according to the" colour of the hair
— the cortex, cortical or fibrous portion.

The cortical portion is that upon which
the firmness, elasticity, and colour of the

HAIR.

[ 371 ]

HAIR.

hair depends, and constitutes the greater
portion of its bulk. It exhibits numerous
longitudinal striae, or interrupted dark lines
and dots. When acted upon by strong sul-

Fig. 292.

Magnified 50 diameters.

A hair of moderate size, contained in its follicle, a,
shaft; 6, root ; c, bulb or knob; d, cuticle of the hair;
e, inner sheath of the root ; f, outer sheath of the root ;
g, structureless membrane of the hair-follicle ; h, trans-
verse- and longitudinal-fibrous layer of the same ; i, pa-
Eilla; k, excretory ducts of the sebaceous glands or
jllicles, with their epithelial and fibrous layer ; I, cutis
of the orifice of the hair-follicle ; m, rete mucosum ;
n, cutaneous epidermis; o, termination of the inner
sheath of the root.

phuric or some other acid at a gentle heat,
it becomes at first resolved into plates or
fibres (fig. 293 £) of the most varied sizes,
both as to length and breadth ; but if the
action of the acid be continued, these fibres
become separated into cells (fig. 293 A],
These cells present uneven surfaces, and a
more or less eliptical outline, their true

form being spindle-shaped; but they are
mostly flattened and angular, or curved from
mutual pressure, resulting from their aggre-
gation into the shaft of the hair. The celh
are about 1-500 to 1-300" in length, and

Fig. 293.

Magnified 350 diameters.

Plates and cells of the cortical substance of a hair,
after treatment with acetic acid. A, separate cells.
1, front view (three of them isolated, two united) ; 2,
side view. B, a layer, composed of several cells.

from 1-6000 ^to 1-2200" in breadth. They
mostly contain elongated, dark-looking nu-
clei, 1-1100 to 1-400" in length ; these are
well seen in a colourless hair, heated with
soda or potash (fig. 294 A b, and B} • in
coloured hair they also contain pigment-
granules, to which the colour of the hair is
2u2

HAIR.

[ 372 ]

HAIR.

principally owing. The pigment-granules
are exceedingly minute, about 1-50,000" in
diameter, rounded, and, as existing in the
hair, are mostly arranged in linear groups,

Magnified 350 diameters.

A, Portion of a white hair after treatment with soda,
a, nucleated cells of medulla, free from air ; b, cortical
substance with fibrillation and linear nuclei ; c, cuticle.
B, three isolated nuclei from the cortex.

then* colour and number varying with that
of the hair. The pigment- granules are best
separated by the action of caustic potash or
soda, and they frequently exhibit molecular
motion.

The striated and dotted appearance of the
shaft of hairs is not produced simply by the
nuclei, nor by the pigment, but arises in
part also from the unequal refraction of the
light by the various parts of the cells, and
from the presence of minute spaces filled
with air. The nature of each can always be
determined by attention to the principles
laid down in the INTRODUCTION.

Towards the bulb, the cells of the cortex
are more distinct, less elongated, and, as well
as the nuclei, more easily isolated when
treated with acids (fig. 295), whilst in the
bulb itself they are round (fig. 296), 1-4000
to 1-1800" in diameter, closely crowded,
and sometimes containing only a colourless
nucleus, at others pigment-granules.

The medulla, like the cortex, consists ot a
number of cells. Its structure is best ob -
served in a hair which has been treated with
soda or potash. The cells are then seen to

Fig. 295.

Fi*. 96.

Magnified 350 diameters.

Fig. 295. Two striated cells from the cortex of the root

close above the bulb, with nuclei.
Fig. 296. Cells from the deepest portions of the bulb ;

a, from a coloured bulb, with pigment-granules and

partly concealed nuclei ; 6, from a white hair, with

distinct nuclei and a few granules.

be arranged in one or more linear series
(fig. 294 a) ; they are angular or rounded,
1-2000 to 1-1000" in diameter; and if the
action of the alkali has not been too long
continued, they exhibit a nucleus ; they fre-
quently also contain one or more granules or
globules of fat (fig. 297). In the shaft and

Fig. 297.

Magnified 360 diameters.

Medullary cells with pale nuclei and fatty granules,
from a hair treated with soda.

upper part of the root of the hair, these
cells contain air, which gives them a dark or
black appearance by transmitted lio-ht \ and
it was the generally received opinion, until
we pointed out the error several years ago,
that this darkness or blackness arose from
the presence of pigment. The contrary,
however, may be easily proved by mace-
rating the hair in oil of turpentine or any
liquid, when the air escapes in bubbles and
becomes displaced by the liquid ; moreover,
on drying the hair, the air and black ap-
pearance return. PI. 29. fig. 1 represents a
white hair;, in which the medullary cells of

HAIR.

[ 373

the lower part are filled with Canada bal-
sam, whilst those of the upper portion still
contain air. Ap;ain, examination by reflected
light is equally conclusive ; for under it the
black medullary portions become white,
which would not be the case did the black-
ness arise from pigment. PI. 29. fig. 9 illus-
trates this in the hair of the Lion ; where
a represents the hair as seen by transmitted,
and b by reflected light.

Cuticular coat. The shaft and root of
the hair, above the termination of the inner
root-sheath, are coated externally by a
firmly adherent, thin, simple, membranous
layer, consisting of flat, imbricated, epithe-
lial scales. In the natural state of the hair,
the existence of these scales is only indi-
cated by the presence of irregularly trans-
verse and anastomosing lines seen upon the
surface, or slight dentition of the margin
(fig. 298-4). But when the hair has been

Fig. 298.

HAIR.

Fig. 299.

Magnified 160 diameters.

A, surface of the shaft of a white hair, the curved
lines indicating the free margins of the epidermic scales.
.B, scales isolated by the action of soda.

treated with an acid or an alkali, the scales
become separated. Their free margins are
directed towards the unattached end of the
hair. The scales are much more distinct
without treatment, in the hair of the newly-
born infant (PI. 29. fig. 3). They are very
transparent, somewhat quadrangular, flat-
tened or curved cells (fig. 298 2?), not
containing a nucleus ; their margins or edges

f /

Magnified 250 diameters.

Portion of the root of a dark hair, slightly acted upon
by soda : a, medulla, the cells still containing air ; 6,
cortex with pigment; c, inner cuticular layer; d, outer
cuticular layer; e, inner layer of the inner root-sheath;
/, outer perforated layer ol the same.

are often black, and, as the other parts
are transparent, they are apt to be over-
looked. They are about 1-700 to 1-500" in
length, and one half or one third of this in
diameter.

In the lower part of the root, below the
termination of the root-sheath, the cuticu-
lar coat is double, or consists of two layers.
The above-mentioned cuticle of the shaft
and upper part of the root forms the con-
tinuation of the innermost of these, which
possesses nearly the same structure, except
that the scales of which it consists are some-
what longer, and directed more obliquely
outwards. These layers are best seen in a
hair treated with an alkali, especially with
the aid of pressure ; they then become se-
parated (fig. 299), the inner, with the roo
of the hair, assuming an undulating form,
and remaining firmly adherent (c), whilst
the outer (d) remains attached to the inner
root-sheath, its cells also being broad and
without nuclei. At the bulb, both these
layers become transformed into soft cells
broader than long, with transverse nuclei,
finally becoming fused with the round cells
of the bulb.

HAIR.

C 374 ]

HAIR.

The hair-follicles are pouches, about 1-10
to 1-4" in length, pretty closely surrounding
the hairs, and extending in the short hairs
into the substance of the upper layer of the
cutis ; but in the long hairs, into its deepest
portion, or even into the subcutaneous cel-
lular tissue. They may be regarded as pro-
longations of the skin, with its components,
the cutis, basement-membrane, and epider-
mis. Hence three parts are distinguishable
in them : an external, fibrous, very vascular
portion — the proper hair- follicle ; a base-
ment-membrane ; and a non- vascular cellu-
lar coat — the epidermis of the follicle, or,
because it surrounds the root of the hair,
the root-sheath.

The fibrous portion of the follicle con-
sists of two layers or membranes. The
outer one (fig. 292^) is the thicker, and
contains vessels and nerves. Its inner sur-
face is connected with the inner layer; ex-
ternally it is attached to the surrounding
areolar tissue ; and above, it is continuous
with the outer layer of the cutis. It con-
sists of common areolar tissue, the fibres
of which are longitudinal, with elongated
spindle-shaped nuclei. The inner layer
(fig. 300 0) is much more delicate, and only
extends from the base of the hair-follicle
to the orifice of the sebaceous follicles. It
consists of a single layer of transverse fibres,
with long and narrow nuclei, resembling
unstriated muscular fibres.

The third layer (fig. 300 6), or basement-
membrane, is transparent and structureless,
and extends from the base of the follicle,
without apparently covering the papilla, as
far as the inner root-sheath, and perhaps
higher. It presents delicate transverse
anastomosing lines, producing a fibrous
appearance.

The pulp or papilla of the hair (fig. 292 i)
belongs to the follicle, and corresponds to a
papilla of the skin. It is rounded or oval,
1-96 to 1-480" in length, is connected with
the fibrous coat of the follicle by a kind of
stalk, and consists of indistinctly fibrous
areolar tissue with nuclei and granules of
fat, but contains no cells.

The two root-sheaths consist of the epi-
dermic covering of the hair-follicle. The
outer (fig. 292/) is the continuation of the
rete mucosum of the skin, and lines the
entire follicle. Its lower part is in contact
externally with the basement-membrane of
the follicle; but above the termination of
the inner transverse layer of the follicle, it
is in direct contact with the outer or longi-

tudinal layer. It consists of several layers
of nucleated cells, resembling those of the
rete mucosum of the skin, the outer having
their long axis perpendicular to that of the
hair, the others, especially towards the bulb,
being rounded. This outer root-sheath is
most distinct in the follicles of the skin of
the negro, from which it may be withdrawn
with the epidermis after maceration.

Fig. 300.

Magnified 300 diameters.

Portion of the inner fibrous coat and basement-mem-
brane of a hair-follicle : a, inner coat with transverse
fibres and elongated transverse nuclei; b, basement-
membrane, seen as it were in section ; c, its lacerated
margins ; d, fine lines (fibres?) on its inner surface.

The inner root-sheath '(fig. 299, e,f) forms
a transparent, very firm and elastic, yellow-
ish membrane, extending from near the base
of the hair-follicle to near the mouths of the
sebaceous follicles, where it terminates ab-
ruptly with a jagged margin. Externally
it is connected with the outer root-sheath,
internally with the outer layer of the cuticle
of the hair ; hence no interval exists natu-
rally between it and the hair. At first sight
it appears as a perfectly homogeneous mem-
brane, but on closer examination it is seen
to be distinctly cellular ; it consists of two

HAIE.

[ 375 ]

HAIR.

or three layers of polygonal, longish, trans-
parent cells, with their long axis parallel to
that of the hair. The outermost (Henle's)
layer (figs. 299 /, 301 A) consists of long,

Fig. 301.

Magnified 350 diameters.

Elements of the inner root-sheath. A, external layer :
1, isolated plates; 2, the same in connexion, showing
the interspaces (a) between the cells (6). S, cells of the
inner non-perforated layer. C, nucleated cells of the
lower part of the inner sheath, which consists of a single
layer only.

flattened, non-nucleated cells, from 1-700
to 1-500" in length, with fissures between
them, forming a fenestrated layer. The in-
nermost (Huxley's) layer (figs. 299 e, 301 £)
consists of one or two layers of shorter and
broader polygonal cells, from 1-1200 to
1-600" in length j their nuclei, which exist
in the lower part only of the coat, are often
broader at the ends than in the middle,
sometimes curved and pointed. At the base
of the hair-follicle, the inner root-sheath

consists of a single layer only of beautiful,
polygonal, nucleated cells (fig. 301 C) ; these
becoming soft, delicate and rounded, gra-
dually pass into the outer layers of the round
cells of the bulb.

In regard to development, the rudiments
of the hair appear as processes of the rete
mucosum descending in the substance of
the cutis. These are solid, and consist of
cells, the internal of which become horny,
and form first a small slender hair in the
axis of the process, next an inner sheath
surrounding the former, whilst the outer
cells remain soft, and form the outer sheath
and the cells of the bulb.

After birth the foetal hair appears to be
completely shed, new hairs being formed in
the old follicles, which displace the first set,
as shown in figs. 302, 303.

Fig. 302.

Fig. 303.

I

Magnified 20 diameters.

Eye-lashes of a child a year old. A exhibits a process
(m) of the bulb or outer root-sheath, in which the cen-
tral cells are elongated, and form a cone distinct from
the outer cells. B, one more advanced, in which the
inner cone has become developed into a hair and an
inner root-sheath : a, outer, 6, inner root-sheath of the
young hair ; c, pit for the pulp ; d, bulb ; e, shaft of the
old hair ; /, bulb,#, shaft, h, summit of the young hair ;
i, sebaceous follicles ; k, three sudoriparous ducts open-
ing into the upper part of the hair-follicle.

The hairs sometimes found developed
upon mucous membranes, and within en-
cysted tumours and ovarian cysts, possess
the normal structure in every respect.

Of the morbid states of the human hair,
we need mention only the loss and change

HAIR.

[ 376 ]

HAIR.

of colour, and the presence of fungi. When
the colour entirely vanishes, and the hair
becomes white or grey, the cells of the me-
dulla contain abundance of air. This arises
from degeneration or impaired nutrition;
the liquid contents of the cells are not sup-
plied in sufficient quantity ; they therefore
evaporate, and the cells being prevented
from collapsing by their adhesion to each
other and to the firm cortex, become filled
with air, which replaces what would other-
wise constitute a vacuum. Fungi are found
in FAVUS upon the cortex of the hair,
within the follicles, and even within the
hair itself, as is stated. In Porrigo decal-
vans also, fungi are stated to occur in the
hairs.

The principal differences between the hair
of man and of animals, and that of animals
from each other, relate to — 1, the size; 2,
the relative proportions of the cortical and
medullary structures ; 3, the locality of the
pigment ; 4, the arrangement of the medul-
lary cells ; 5, the comparative amount of
true hair, and woolly hair, down, or wool ;
and 6, the size and projection of the super-
ficial cortical cells or scales.

Of these we shall give a brief sketch
(PI. 1. figs. 1-3, and PL 29).

The hair of the Mammalia generally is
formed upon the same plan as that of man ;
great variety, however, exists in its com-
plexity of structure and the arrangement of
the component parts.

Quadrumana (PI. 29. figs. 4 & 5). In the
monkey (Indian) (fig. 4), the hair presents
much of the same structure as in man; the
pigment is confined to the cortex, but the
air-cells of the medulla are larger and less
crowded ; this is seen to a greater extent in
the hair of the lemur (fig. 5).

Cheiroptera. In the bats (PL 1. fig. 2;
PL 29. figs. 6 & 7), a striking character is
the peculiar development of the cortical
scales of the surface. In the hair of the
common bat (PL 1. fig. 2), which is one
of the TEST-OBJECTS, and Australian bat
(PL 29. fig. 7), this character is not so
striking as in that of the Indian bat (fig. 6),
in which the scales are grouped in whorls
at pretty regular intervals along the shaft,
and project considerably beyond the sur-
face. The pigment is principally confined
to these whorled scales. In some of the
white hairs of the bat, the individual scales
are very beautifully seen (PL 1. fig. 2 c).

Insectivora. The hair of the mole (PL
29, fig. 8) bears some resemblance to that

of the bats : but the cells of the medulla
are very distinct. (See SPINES.)

Camivora (figs. 9-13). In this Order the
structure of the hair varies considerably.
In the lion (fig. 9) the cortical cells are di-
stinct, but not projecting; the medullary
cells are very numerous, and the air-spaces
minute, but closely aggregated, as we often
find them in the human hair. In the bear
(fig. 10), the large hairs present much the
same structure as in the lion ; the wool-
hairs differ strikingly from these, however,
in the distinctness of the cortical and me-
dullary cells.

Pachydermata (figs. 14-17). In this Order
the hairs present a development correspond-
ing with that of the skin; being very thick
and complex in structure. In the elephant
(fig. 15, transverse section), each hair re-
sembles a number of hairs fused together.
Scattered through its substance are pale
spots formed by cells containing little or no
pigment, with an irregular perforation in
each, probably arising from rupture of the
cells. Surrounding these medullary centres
are innumerable cortical cells loaded with
pigment. In the pig (fig. 16), the distinc-
tion between the cortex and medulla is not
well marked, and the cells assume a radial
direction, as indicated by those which con-
tain most pigment. In the Cheiropotamus
(fig. 17) the distinction is more evident.

Rwminantia (figs. 18-22). In this Order
the hair presents great variety. In the
camel (fig. 18) and dromedary (fig. 19), the
true hair exhibits much the same structure
as that of the higher Orders, whilst in the
deer (fig. 20, moose-deer; fig. 21, musk-deer)
the medullary portion is enormously deve-
loped at the expense of the cortical portion;
in no hair is the cellular structure more
distinct than in the two latter, the medulla
closely resembling a piece of vegetable cel-
lular tissue. The wool-hair in this class
presents the characteristic structure. That
of the camel (fig. 18 b) agrees in structure
with the type of wool from the sheep
(fig. 22) in its softness, flexibility and
waviness, and in the distinctness of the
cortical cells.

Edentata (figs. 23 & 24). The difference
between the hair of the three-toed sloth
(fig. 23) and that of the armadillo (fig. 24)
is well-marked. In the former, the cor-
tical cells take a remarkably oblique or
radiating course, whilst in the latter they
run longitudinally.

Eodentia (figs.' 25-35). In this Order the

HAIR.

[ 377 ]

HAIR.

pigment is met with sometimes in the me-
dulla, at others in the cortex. The arrange-
ment of the air-cells is often very beautiful,
and has rendered these hairs favourite
microscopic objects. Portions of a mouse-
hair in various parts of its length are re-
presented in fig. 27, a forming the free end.
Fig. 28 displays two portions of the same
hair as histolyzedby treatment with solution
of potash. The cortical parts have not been
resolved into their component cells, whilst
those of the medulla have assumed their
rounded and natural form, and exhibit mi-
nute granules of pigment, with larger glo-
bules of fat. The arrangement of the me-
dullary cells in two rows is seen in fig. 28 b.
The pigment within the cells in situ is seen
in fig. 31 6, from the rabbit. The wool
presents its characters in a marked degree,
the projection of the outer layer of cortical
cells and the distinctness of the medullary
air-cells being very evident.

Marsupialia (figs. 36 & 37). In this cu-
rious Order the hair greatly resembles that
of the Rodents. That of the kangaroo pre-
sents very beautifully imbricated cortical
cells (fig. 36).

Monotremata. The structure of the hair
of the Ornithorhynchus is as peculiar as
that of the animal in general. It presents
that of hair and wool combined (fig. 38).
The basal portion resembles wool, and is
very long and narrow ; the structure of two
pieces in different parts of its length is seen
in fig. 38 c and d. At the end of this por-
tion is attached the proper hair containing
the pigment within the cortical substance
(b) ; tig. 38* represents the surface-view of
the hair, showing the imbricated scales.

In Birds the hair is replaced by FEA-
THERS.

The hair of the Invertebrata does not
present the same structure as that of the
higher animals ; some physiologists have
therefore limited the term hair to the fili-
form epidermic formations of the Mam-
malia, whilst others admit the occurrence
of hair in all classes of the animal kingdom.
At all events, the hairs of the Invertebrata
are not usually composed wholly of epider-
mis. They consist of an outer cortical or
epidermic layer, frequently coloured, and
upon which their firmness depends ; lining
this is sometimes a prolongation of the
cutis, at others a colourless substance which,
when the hair is dried, presents an irregular
cell-like appearance and contains air, so as
o resemble the air-cells of the hair of the

Mammalia. In other instances the hair is
completely solid, but exhibits no trace
whatever of cell-structure. It remains to
be shown whether the latter may represent
the epidermis hardened in an amorphous
state, and whether those lined with cutis
may be regarded as epidermic formations
upon an exserted papilla of the skin -, whilst
those presenting the air-cells when dried
correspond to an outer hardened epidermic
layer, and an inner retaining its distinctly
cellular state. In those lined with cutis,
the circulation can sometimes be observed.

We have space to notice only a few in-
stances of variety of form, many of which
occur, and have long rendered these hairs
interesting and elegant microscopic objects.
Thus, in some of the Arachnida they are
feathery, giving oft' slender lateral branches,
as in Lycosa (PI. 29. fig. 40), Epeira (PI. 6.
fig. 8 6), Acarus (PI. 6. fig. 1 b), &c. j in
others these branches are directed forwards
near the middle of the shaft, but recurved
at the end, as in Mygale (the bird-catching
spider) (PI. 29. fig. 41); or, while the
branches on the shaft resemble the above,
the end of the hair is thickened, cylindrical
and longitudinally striated, with minute
setae arising from the striae, as in fig. 42 ;
again, some of them are simple, but fur-
nished with spiral striae (Epeira, PL 6.
fig. 8 a) ; in Trombidium they are sometimes
very elegantly feathery.

In Insects, Arachnida, &c., they often
appear to rise from a bulb at the base ; but
the bulb is not solid, and bears no resem-
blance in structure to the bulb in the
Mammalia; it consists of a thickening or
fold of the epidermis of the skin, not of the
hair, from which it is separated by a white
ring, indicating thinness of this coat, and
often corresponding to a joint; the hair
arises from the base of a depression situated
within the annular bulb. The hair of some
of the larvae of the Dermestidae is very
beautiful, and is used as a TEST-OBJECT.
Two forms are met with : in one (PI. 1.
fig. 1 c) the shaft is simply covered with
densely aggregated, minute, spinous secon-
dary hairs; in the other (PI. 1. fig. 1 a, 6),
the spines or scales upon the shaft are nar-
row, acute, and placed in pretty regular
whorls ; in the uppermost whorl they are
broader, the spines remaining as midribs,
whilst the margins are more developed, the
whole resembling a flower with four or five
petals; but at the end of the hair, the
scales are longer, narrower, and recurved,

HAIR.

[ 378 ]

HAIRS.

each midrib being terminated below by a
little knob.

The examination of the hair and its dis-
section can only be effected by the aid of
chemical reagents, especially sulphuric acid,
solution of potash or of soda. These should
first be used cold ; and if no separation of
the components ensues, heat even to boiling
must be applied ; the subsequent addition of
water is sometimes advantageous. Sections
of hair can be made with a razor, a bundle
of hair being fixed between two flat pieces
of cork, or between two cards. Transverse
sections of the human hair can be obtained
by shaving a second time, an hour or two
after the first ; the sections should then be
washed in water. The cortical cells are
most beautifully seen in white hairs which
have been thoroughly soaked in oil of tur-
pentine, and mounted in Canada balsam.
The air-cells of the medulla are best ob-
served in hairs which have been mounted
in balsam without the previous application
of turpentine. The sheaths of the hair
keep best in solution of chloride of calcium
or glycerine.

Many of the structures of the hair of the
Mammalia may be well observed in the
large hairs or bristles (whiskers) of the ox,
&c. ; in these also the pulp is seen to contain
blood-vessels, which have not been detected
with certainty in that of man. They also
exhibit bands of smooth muscular fibres,
arising from the cutis, descending through
the hair-follicles, and terminating below
the sebaceous follicles, forming the erectores
pili.

The hairs of some animals polarize light.
An interesting object of this kind may be
made by placing two series of the white
hair of a horse in balsam, so as to cross
each other at an angle, and viewing them
by polarized light (PL SO.^fig. 39).

In regard to the discrimination of the
hairs of one animal from those of another,
we believe that the examination of indi-
vidual hairs can in general be but little
depended upon; whilst a comparison of
their form, length, and breadth, with the
proportion of the true hair to that of the
wool, conjoined with the consideration -of
the internal structure, may often enable
an observer to arrive at a satisfactory con-
clusion.

BIBL. Kolliker, Mikr. : Eble, Haare in
d. gesammt. organ. Natur ; Henle, Allg. An. ;
Todd & Bowman, Phys. of Man ; Erdl,
Miinchen. Ahh. Bd. iii. ; Huxley, Med. Gaz.

1845; Griffith, ibid. 1848, 844; Heusinger,
Histol. ; Gurlt, Mull. Archiv, 1836 ; Aikin,
Arts and Manuf. ; Bonders, Mulder's Phy-
siol. Chem.-, De Morgan, Phil. Tr. 1859
(Crustacea); Pfaff, D. mensch. Haar. in
phys., pathol, $ forens. Bedeut. 1869 ;
Goette, Schnitzel Archiv, 1868, 273 ; Bie-
siadecki, Strieker's Handb. 600 ; Hofmann.
M. M. Jn. 1873, 167 ; Frey, Histolog. 1876,
419 ; Sorby, Jn. Linn. Soc. 1881, xv. 337.

HAIRS OF PLANTS, trichomata or tri-
chomes. — The term hair is applied in botany
to filamentous productions upon the surface
of the organs of plants, consisting of one
or more cells arising out of and constituting
part of the epidermal structure. Hairs of
plants present a great variety of conditions :
in the simplest kind— those "composed of a
simple, cylindrical, conical, bifurcated or
stellate cell — they may be varied in form
by the peculiar shape of the constituent
cell, in individual character by the presence
or absence of special secretions in the cell-
cavities, and in their collective character by
the mode of arrangement on the epidermis,
since they may be few and scattered, or so
numerous as to form a velvety coat. Com-
pound hairs, namely those composed of a
number of cells, vary in like manner, and,
moreover, in the examples where the cell-
walls acquire considerable thickness, pass
gradually from pure hairs into bristles, and
thence into the structures called THOBNS
(distinguished from true spines by being
appendages of the epidermis). The stellate
forms also present many variations inter-
mediate between hairs proper and SCALES.

These structures are interesting to tha
microscopist on account of the variety and
often extreme elegance or curiosity of their
forms. They likewise strongly attract the
attention of the physiologist from the sim-
plicity of their organization and their free
condition, allowing the phenomena pre-
sented by the cell-contents to be readily
observed under the microscope. In reference
to their characters as microscopic objects,
it will suffice to indicate their principal
modifications, and state a certain number
of examples. For this purpose they may
be classified as follows : —

Simple hairs: unbranched, Cabbage-leaf
(Brassica, fig. 304), (Enothera, Dictamnus
(PI. 28. fig. 39 «), Anchusa (fig. 17) ; bifur-
cated, Capsella (fig. 36), Draba (fig. 307) ;
inflated or capitate, Antirrhinum (fig. 306
and PI. 28. fig. 34), Salvia (fig. 305), Helle-
borusfostidus ; branched, in many Crucif era>,

HAIRS.

[ 379 ]

HAIRS.

as Sisymbrium Sophia (fig. 35), Alternan-
thera civilians (fig. 37); stellate, Alyssum
(fig. 308). Very often hairs composed of a
single cell are supported upon a short stalk,
and then developed horizontally in two
directions, as in Grevillia lithidophylla (fig.
29) ; in several so as to form a star, as in
Deutzia scabra (fig. 26*), Alyssum (fig. 28).
Structures analogous to the last occur upon
the septa of the air-cavities of the Nymphse-
aceae, such as Nuphar lutea (fig. 15), Vic-
toria, &c.

Fig. 304. Fig. 305.

Fig. 306.

Hairs of :—
Brassica (leaf). Salvia (calyx). Antirrhinum (corolla)*

Fig. 307.

Draba (leaf). Alyssum (leaf).

Magnified 100 diameters.

Compound Hairs. These exhibit a similar
diversity of character, and often imitate, on
a larger scale, the forms of the simple hairs ;
they may be uribranched, as in the hairs of
the garden Pelargonia (PL 28. fig. 18), and
a large proportion of ordinary silky hairs
upon "the epidermis of plants. COTTON is a
striking example, consisting of the hairs of
the seeds of Gossypium (fig. 1).

Commonly these hairs are cylindrical; but
not unfrequently one or more of the upper-
most or all the component cells are expanded
into a more or less globular form. Capitate
glandular hairs often occur on corollas, and
particularly on the inner scales of leaf-buds :
examples — the bulbils of Achimenes (fig.
32), the corolla of Digitalis (fig. 33), Lysi-
machia vulgaris (fig. 40), Scrophularia no-

dosa (fig. 41), Bi-yonia alia (fig. 42), the
inner scales of the winter leaf-buds of the
ash, &c. Or the hairs are torulose, as in
Lamium album, the common white Dead-
nettle ; or moniliform or necklace-shaped,
as on the stamens of Tradescantia (fig. 311)
the Marvel of Peru (Mirabilis, fig. 309)!
The transition from these to the branched
forms is presented commonly in the simpler
forms of the pappus of the Composite, as
in that of the Groundsel, which has toothed
hairs ; in other examples the lateral teeth
grow out into branches, as in the species of
Hieracium and other Composite, presenting
pinnate or plumose forms, according to the
extent of ramification. The seeds of Ca-
talpa Bungeana bear a fringe the hairs of
which resemble PITTED DUCTS. Verbascum
Thapsus (PI. 28. fig. 19) has compound hairs
branched at the joints. Compound hairs
likewise exhibit the horizontal development •
the hairs of the garden Chrysanthemum are
horizontal navicular cells, supported on a
tall articulated pedicle (fig. 30) ; the stellate
hairs of the Ivy (fig. 27) are compound and
supported on a short stalk-cell. Very varied
forms of compound, more or less stellate
hairs occur on the leaves in the orders Jas-
minacese and Oleaceae. The last form a
transition to the scales of the Eleae-naceaa
and many Ferns, such as Acrostichum

Fig. 309.

Fig. 310.

Fig. 311.
p

Hairs of:—

Mirabilis. Antirrhinum (calyx). Tradescantia (stamen).
Magnified 100 diameters.

The hairs above noticed are mostly soli-
tary. In the Malvaceae (Hibiscus) tufted or
stellate groups of hairs are met with ; and
in the air-cells of Utricularia are seen
curious groups of four hairs. Marrubittm
creticum is another example of this kind of
structure (fig. 47).

Almost all of the above-described forms
of hair may contain merely watery colour-
less or coloured contents ; or they may have

HAIRS.

[ 380 ]

HAIRS.

one or more of the component cells filled
with special oily, resinous, or saccharine
secretion. In the latter condition they are
termed glandular hairs. The characters of
these organs are spoken of under the head
of GLANDS and SECRETING ORGANS of
PLANTS. The gum-resinous secretion found
upon the buds of trees (^Esculus, &c.) is
formed by glandular hairs.

Some of the hairs with watery cell-con-
tents present favourable opportunities for
observing the ROTATION of the protoplasm;
for example, the young hairs of the stamens
of Tradescantia or spider-wort; the sting-
ing hairs of nettles also show this when
young ; and probably it might be observed
in all young hairs, where sufficiently trans-
parent and uninjured. One precaution
greatly facilitates the observation — namely,
to dip the hairs into alcohol for an instant,
find immediately plunge them in water ;
after this operation, the structure is readily
wetted by water, and no longer obscured by
the abundance of air-bubbles that remain
entangled with and adherent to the surface
of the fresh hairs. These young hairs like-
wise exhibit at their apices the various con-
ditions of the contents (nucleus, protoplasm,
&c.) of cells multiplying by division (PI. 47.
figs. 8 & 9). The circulation takes place in
the dark streaks represented as forming a
network connected with the nuclei (n).

Stings, such as those of the Nettle (PI. 28.
fig. 8), consist of simple cells having a
bulbous base enclosed in a cellular case,
formed by the growing-up of the epidermis
round the base of the hair; the latter tapers
away upward to near the apex, where it
again expands into a little globular head.
The walls are rather thick and spirally stri-
ated. The bulbous base is filled with the
irritating liquid, which exudes when the
knob-like head is broken off, through the
tension of the cellular investment of the
sac.

The intimate structure of the hairs of
plants presents many points of interest. The
cells are of course composed of a cellulose
wall, with contents varying according to
age and other circumstances. When young,
they are always densely filled with proto-
plasm (PI. 47. figs. 8 & 9), which becomes
gradually excavated by vacuoles, and ex-
panded so as to form a mere reticulation or
a few streaks upon the wall, mostly con-
nected with an evident nucleus. The cavity
of the cell is then tilled, in hairs proper, with
watery cell-sap, sometimes coloured, as in

the petals and stamens of many flowers, by
the same liquid colouring-matter as the cells
beneath the epidermis ; stings are filled with
acrid watery juice, — glandular hairs with
various secretions, which, like the watery
juices, appear at first in vacuoles, gradually
occupying the place of the protoplasm
which follows the expanding cell-walls.

Hairs, being epidermal structures, possess
a more or less evident cuticular layer, which
may be detached by the action of acids
(fig. 199, p. 295); sulphuric acid often
causes this to separate and expand as a kind
of vesicle from the surface of the hair, as is
shown in PI. 28. fig. 13 (Siphocampylus) ;
the cuticle of the full-grown moniliform
hairs of Tradescantia may be separated in
like manner (see EPIDERMIS). This cuticle
also exhibits in many cases the same mark-
ings which occur on the surface of the
epidermis of certain plants, as Ifelleborus,
Cakile, &c. (PI. 28. figs. 9 & 10), consisting
of elevated spots, ridges, reticulations, &c.
composed entirely of thickenings of the
cuticular layer. This is well seen in the
hairs of the Boraginaceae, e. g. Anchusa
(fig. 17), the Cruciferae, as of Farsetia,
Cheiranthus, &cv or Delphinium (fig. 16).
The spiral striae on the sting of Urtica urens
(fig. 8) appear to be of similar nature.
T. West has described the raised markings
upon some hairs as bulgings or wrinkles in
the cell-wall.

Finally, it is necessary to mention the
remarkable structure of the hairs upon the
surface of the seeds and pericarps of certain
plants among the Acanthaceae, Polemo-
niaceae, Labiatae, Compositae, &c. Those
of the ACANTHACEAE have been spoken of
partly under that head and under ACAN-
THODIUM. They are hairs composed of
cylindrical cells, simple (JRuellia, PI. 28.
fig. 21), or conjoined into a compound and
branched hair (Acanthodium, fig. 24), the
cell-walls of which receive when young
a spiral (fig. 24) or annular (fig. 21) fibrous
deposit, and subsequently become partially
disorganized ; so that, if placed in water in
the mature state, the primary cell-wall
almost dissolves into a kind of jelly, and
the spiral-fibrous structure expands with
elasticity. The conditions are similar in
Collomia (fig. 22), and, according to Schlei-
den, in Gilia, Ipomopsis, Polemonium, Can-
tua, &c. among the Polemoniacese ; and
somewhat the same in many species of Sal-
via (fig. 23), Ocymum, Dracocephalum mol-
davicum, &c. among the Labiatae. In Cobcea

HALACARUS.

[ 381 ]

HALIONYX.

scandens, the spiral-fibrous hairs take rather
the form of minute scales, and they do not
spontaneously expand elastically (PL 28.
fig. 20). Among the Compositse, these
spiral-fibrous hairs have been observed on
the pericarp of Ituckeria, some species of
Trichocline, Euriops, Mesogramma, Doria
Cluyticefolia, Oligothrix gracilis, and some
species of Senecio. Spiral cells also occur
on the seed of Hydrocharis. The best way
to observe the elastically expanding hairs is
to place a thin slice of the skin of the seed
on a slide in a little alcohol, which does not
soften the cell-wall : when the object is in
focus, the addition of a little water causes
the gelatinous softening of the cell-walls,
the spiral fibres fly out from the surface of
the seed-coat and show clearly the charac-
ter of these beautiful objects. The primary
membrane may be detected, even in its
gelatinous state, by adding sulphuric acid
and iodine, which produce a purplish or
violet colour. Further remarks on this head
will be found under SPIRAL, STRUCTURES.
The hairs on the stigma of Campanula
are remarkable for the intussusception which
is observed to take place in the mature hairs.
The filiform processes growing from the
under surface of the frondose Hepaticae,
the thallus of Lichens, the prothallium of
Ferns, &c., are commonly called radical
hairs. In most cases they present no re-
markable points of structure ; in Marchan-
tia, however, peculiar spiral markings have
been detected (see MARCHANTIA).

BIBL. Meyen, Secretions-orc/ane d. Pflan-
zen, 1837 ; id. Pflanzen-physiol. ; Cohn, Cu-
ticula, Linncea, xxiii. 337, 1850 ; Schleiden,
Mutter' 8 Archiv, 1838; Beitr. z. Botanik,
Leipsic, 1844, i. 121 (Sc. Memoirs)-, De-
caisne, Arm. Sc. Nat. 2 ser. xii. 251, pi. 4 ;
Leighton, Ann. N. H. vi. 257 ; Brongniart,
Ann. Sc. Nat. 2 s<§r. xii. 244, pi. 4; Pril-
lieux, Ann. Sc. Nat. 4 ser. v. 5; Tuffen
West, Qu. Mic. Jn. vii. 22; Weisse, D.
Pflanzenhaare, 1867; Hanstein, Bot. Zeit.
1868, 697; Kauter, Trichomgeb. 1871;
Martinet, Ann. Sc. Nat. 1872, xiv. ; Sachs,
Bot. 163.

HALAC'ARUS, Gosse.— A genus of
marine Acarina.

Char. Body sometimes covered with a
dorsal shield ; rostrum bulbous, pointed ;
palpi terminated by a fang-like claw ; legs
formed for walking, arising from the outer
margin of the body, directed two pairs for-
wards and two backwards, and with a pair
of hooks.

Five species : found crawling upon sea-
weeds at low water, or in dredgings.

BIBL. Gosse, Mar. Zool. i. 177 ; Murray,
Econ. Entom. 205 (figs.).

HALARACH'NE, Allman.— A genus of
marine Acarina ; family Gamasea.

Body elongate subcylindrical, with an
anterior dorsal plate.

H. halichcBri. In the posterior nares of a
seal (Halichwrus gryphus) ; length 1-8".

BIBL. Allman, Ann. N. H. 1847, xx.
47 ; Murray, Econ. Ent. 167 (fio-a.).

HALE'CILDvE, Hincks.— A family of
Hydroid Zoophytes.

Gen. : Halecium and Ophiodes.
HALE'CIUM, Oken.— A genus of Hy-
droid Zoophytes, family Sertulariidaa.

Distinguished by the plant-like polypi-
dom, the stem consisting of numerous
parallel capillary tubes, and the cup-like
nearly sessile cells arising alternately on
opposite sides of the stem, one under each
joint.

H. halecinum. Vesicles oval or oblong.
Common on shells and stones in deep water ;
4-10" high.

H. Beanii. Vesicles calceoliform. Rare.
H. muricatum. Vesicles spinous.
5 other species.

BIBL. Johnston, Brit. Zooph. 58 ; Hincks,
Hydroid Zooph. 220.

HALIOHOND'RIA, Flem.— A genus of
SPONGES.

HAL'IDRYS, Lyngb.— A genus of Fu-
caceae (Fucoid Algae), containing one British
species, If. siliquosa, common on rocks and
stones somewhat above low-water mark.
It is readily distinguished by its pod-like
septate air-vessels. The fructification, which
is terminal on the branches, much resembles
that of Fucus, except that the interior
of the receptacles is filled up with firm
polygonal cellular tissue. The antheridia,
moreover, are terminal on their pedicels,
often in tufts, short in form, and inter-
mixed with spore-sacs in the same concep-
tacle.

BIBL. Harvey, Br. Mar. Alg. 15, pi. 1 C ;
Thuret, Ann. Sc. Nat. 3 ser. xvi. 8, pi. 3

HALIO'NYX, Ehr.-A genus of Diato-
maceae.

Char. Frustules single; valves equal,
circular, surface radiate, the rays not com-
mencing at the umbilicus; no internal septa.
Marine.

H. senarius. Rays six, the intervening
spaces with shorter rays of equal length
parallel to the larger, and with transverse

HALISARCA.

[ 382 ]

HAPLOMITRIUM.

laxly cellular lines ; umbilicus punctate,
entire ; diam. 1-720".

H. undenanus (PI. 18. fig. 51). Rays
eleven or twelve.

BIBL. Ehr. Ber. Berl. Akad. 1844, 198.

HALISAR'CA,Duj. (HYMENIACIDON,
Bowerbk.). — A genus of marine Sponges.

Forms a thin semitransparent gelatinous
amber crust on rocks and shells, with indi-
stinct oscula and pores.

H. Dujardinii. The only species.

BIBL. Johnston, Br. Sponges; Gosse,
Mar. Zool. i. 6 ; Bowerbank, Br. Spong. ii.
224.

HALIS'ERIS, Tozzetti. — A genus of
Dictyotaceae (Fucoid Algaa), containing one
British species, with a brownish olive,
sometimes forked frond with a midrib, from
4" to 1' high, having a very powerful offen-
sive smell when fresh. The fructification
is produced in sori, arranged in lines on
each side of the midrib, or scattered, con-
taining large spores.

BIBL. Harvey, Mar. Alg. 36, pi. 6 B.

HALOCY'PRIS, Dana.— A marine Os-
tracode, with very thin, subquadrate, saddle-
shaped valves, beaked in front at the upper
angle. The closely allied Conchcecia, Dana,
has longer and subrectangular valves. Both
are related to Cypridina, and have two
pairs of feet, weak upper antennae, distinct
mandibles, large frontal tentacle, and no
eyes.

Living in the Atlantic and Mediterranean.

BIBL. Dana, Expl Exped., Crust. 1301 ;
Brady, Linn. Tr. xxvi. 469.

HALTE'RIA, Duj.— A genus of Infu-
soria, family Halterina.

Char. Body almost spherical or top-
shaped, with an anterior circle of cilia, and
a peripheral row of longer slender setae,
which by sudden contraction produce a
leaping motion. Freshwater.

H. grandinella=Trichodina grandinella,
Ehr. (PI. 50. figs. 11, 12) ; greatest breadth,
1-850".

H. volvox ; like H. grandinella, but with
a second peripheral row of shorter and
closer cilia. 3 other species.

Stein points out the resemblance of this
animalcule to the swarm-germs of an Act-
neta found upon Cyclops.

BIBL. Duiardin, Inf. 414 : Stein, Inf. :
01. & Lach. Inf. 369; Kent, Inf. 631.

HALTERI'NA, 01. & Lach.— A family
of Peritrichous Infusoria.

Char. Free, globose or flask-shaped, with

an anterior circle of cilia, and sometimes a
peripheral row of longer setae, which by
their sudden contraction produce a leaping
motion.

Gen. : Halteria, with both cilia and setae ;
Strombidium, with cilia only ; Mesodinium,
with a proboscis and setae ; Acarella, with
cilia and a carapace; Arachnidium, with
stout tentacle-like cilia; and Didinium,
with an anterior and posterior circle of
cilia.

HAL'TICA, 111.— A genus of Coleopte-
rous Insects ; fam. Galerucidae.

H. iwmorum, the " turnip-fly." Oblong-
ovate, black ; elytra greenish black, with a
broad uninterrupted sulphur-yellow streak,
not reaching the apex. Movement jump-
ing.

BIBL. Stephens, Brit. Coleopt. 291.
HALYME'NIA, Ag— A genus of Cry-
ptonemiaceae (Florideous Algae), containing
one British species, found on the southern
shores. It is a somewhat palmate, mem-
branous, rose-coloured sea-weed, usually
from 6 to 12" long, composed of a double
membrane, the layers being separated by a
loose network of jointed filaments, 'fhe
fructification consists of favellidia buried in
the frond, attached to the inner surface of
the membranous laminae, scattered all over
the frond, appearing to the naked eye like
red dots.

BIBL. Harvey, Brit. Alg. 148, pi. 19 D.
HAPALOSI'PHON, Nag.— A genus of
Oscillatoriaceae. Filaments branched, formed
of a single row of cells, with delicate co-
loured, indistinctly lamellar sheaths.

Four species ; " on freshwater plants.
(Rabenhorst, Fl. Alg. 283.)

HAPLA'RIA, Link. See BOTEYTIS
grisea.

HAPLOMIT'RIUM, Noes.— A genus of
Jungermannieae (leafy Hepaticae), contain-
ing one British species, H. (Jungermannia)
Hookeri, an Alpine plant, which has been
carefully studied by Gottsche. It is re-
markable for having leaves (without amphi-
gastria) inserted on all sides of the stem.
The terminal capsule emerges at length
from a large oblong fleshy epigone (fig. 328).
The antheridia (fig. 323) occur in the axils
of the leaves ; they have a double coat, the
interior of which consists of reniform cells
(fig. 322), which become isolated and more
or less dissolved. The spermatozoids, pro-
duced in minute vesicles (fig. 324), resemble
those of the Mosses.

HAPLOPHRAGIUM. [ 383 ]

HELICOSPORIUM.

Fig. 312.

BIBL. Hooker, Brit. Jungermannia, pi.
54 ; Ekart, Syn. Jung. pi. fig. 65 ; Endlicher,
Gen. Plant. No. 474-3; Gottsche, Nova
Ada, xx. 265, pis. 13-20.

HAPLOPHRAG'MIUM, Reuss. — A
sandy Lituoline Foraminifer, either nauti-
loid or crozier-shaped, with simple or com-
pound aperture and undivided chambers.
Recent and fossil.

BIBL. Reuss, Sitzungsb. Ak. Wien, xliv.
381 ; Brady, Mic. Jn. n. s. xix. 29.

HAPLOSTI'CHE, Reuss. See LITTJ-

OLA.

HAPLOT'RICHUM,

Link. — A genus of Mu-
cedines (Hyphomycetous
Fungi), intermediate in
structure between £o-
trytis and Aspergillus.
The spores are developed
from a capitate cell
terminating the septate
erect fertile filaments
(fig. 312).
BIBL. Corda, Ic. Fung.-

New, Syst. PUze, pl/4 Haplotnchumroseum.

Fries, sL. Veget. 470. ^agn. 200 diams.

HARPAC 'TICUS. See ABPACTICUS.

HARPIRHYN'CHUS, Meg.— A genus
of Trombidina (Acarina).

H. nidulans, in the dilated feather-follicles
of the lark and green-finch. (Megnin, Paras.
243, fig.).

HAR'TEA, Wright.— A genus of Alcy-
onidiidse.

Polype solitary; body cylindrical, fixed
at the base ; tentacles 8, knobbed at their
base j basal portion of body thickly studded
with small star-shaped spicula; base and
body of tentacles with long dendritic spi-
cula ; mouth central, with 2 lips ; somatic
chambers 8.

H. elegans. Height 3-4". White, base
dark. West coast of Ireland.

BIBL. E. S. Wright. Qu. Mic. Jn. 1865.
v. 213 (pi.).

HARVEST-BUG. TROMBIDITJM au-
tumnale.

HASSALLIA, Berk. See SIROSIPHON.

HASTERIGERI'NA, Thomson. — De-
scribed by Brady as scarcely separable from
Globigerina (W. Thomson, Proc. R. S. xxiv.
534 ; H. Brady, Mic. Jn. 3, xix. 79).

HAUERI'NA, D'Orb. — One of the
Miliolidce, growing on one plane, subdis-
coidal, and characterized by a cribriform
aperture.

H. compressa (PL 23. fig. 8). Fossil in the

Tertiary beds ; living in tropical seas ; rare
on the British coast.

BIBL. Carpenter. Introd. For. 81.

HAUSTO'RIA.— A term applied to cer-
tain short processes springing from the basal
fibres of the hyphae of moulds, while travers-
ing the intercellular passages of the host-
plants ; they are often expanded at the ends.
They penetrate the parenchymatous cells, and
absorb their contents. They may be readily
studied in Cystopus.

BIBL. Brefeld, Schimmelpilze ; Be Bary,
Beitrage ; Sachs, Hot. 279 (figs.).

HAVERSIAN CANALS. See BONE.

HEART.— The muscular fibres of the
heart present certain peculiarities. The
primitive bundles are more slender than
usual; they frequently anastomose, and
contain normally a few minute granules of
fat : the transverse striae are also often in-
distinct. In disease the fatty matter is often
extremely abundant (PI. 38. fig. 14 a), and
the striae are more or less obliterated.

BIBL. Kolliker, Mik. An. ii. ; Forster,
Path. An.] Wedl, Path. Hist.] Q.uain,
Med. Chir. Tr. 33 ; Rokitansky, Path. An.

HEDR^EOPH Y'S A, Kt.= sessile Bicos-
ceca. One sp., Jersey. (Kent, In/us. 274).

HEDWIG'IA, Hook.— A genus of Mos-
ses. See ZYGODON.

HEIBER'GIA, Grev.— A genus of Dia-
tomaceae.

Char. Fr. compressed, quadrilateral, cel-
lulate, with a punctate surface of the angles,
where they probably cohere : valves with
one longitudinal and several transverse
costae, the longitudinal one terminating at
each end in a blank space.

A. Barbadensis (PI. 52. fig. 4). Barba-
does deposit.

BIBL. Grev. Mic. Trans. 1865, v. 100.

HELICO'MA, Corda.— A genus of De-
mat lei (Hyphomycetous Fungi) ; with the
spores curled into a spiral. Berkeley
considers the distinction between Helicoma
and Helicosporium scarcely tenable, and
Fries includes Helicoma Miilleri, Corda,
under Helicosporium. This plant has been
found on dead wood in this country.

BIBL. Corda, Ic. Fung. i. pi. 4. fig. 219 ;
Berkeley and Broome, Ann. N. H. 1851,
vii. 98 ; Fries, Sum. Veget. 500.

HELICOSPO'RIUM, Nees.— A genus of
Dematiei (Hyphomycetous Fungi), growing
on decayed wood, nearly related to Heli-
coma and Helicotrichum. Helicoma and
Helicosporium are described as having erect
fertile filaments, Helicotrichum creeping

HELICOSTEGIA.

[ 384 ] HELMINTHOSPOmOI.

Helicosporium pul-
vinatum.

Magn. 200 diams.

branched filaments; but Fig. 313.
the distinctions are ob-
scure, as also those be-
tween Helicoma and Heh-
cosporium, the first of
which should have the
spirals closed, the latter
open. Fries and Berkeley
both include Helicotri-
cJmm under Ifelicosporium.
British species :

H. pulvinatum, Fr. (fig.
313). Forming a blackish
or olive pulvinate stratum
over wood, with slender
branched filaments, bear-
ing yellowish-green strings
of'sporidia coiled up into a spiral of about
three turns, very fugacious (Helicotrichum
pulvinatum, Nees).

H. vegetum, Fr. Widely pulvinate-effused,
subolivaceous, at length * black ; fertile fila-
ments erect, stiff, subulate ; spores coiled
into a ring, 3-septate, greyish green.

BIBL. Berk. Hook. Br. FL vol. ii. pt. 2.
335 ; Ann. N. H. 1850, vi. 434 ; vii. 98 ;
Fries, Syst. Myc. iii. 353 ; Sum. Veg. 500 ;
Corda, Sturm, DeutscU. Flora, 3 ser. ii. pis.
15 & 16 ; Nees, Nova Acta, ix. 246, pi. 5.
fig. 15 ; Syst. Mycol 68, fig. 69.

HELICOSTE'GIA.— An order of Fora-
minifera, according to D'Orbigny's system,
comprising those coiled spirally on a single
axis. This feature, however, is common to
several genera which have distinct characters
of structure and habit, and has ceased to be
regarded as typical.

JHELICOS'TOMA, Cohn.— A genus of
Holotrichous Infusoria = Nassula with the
pharynx hooked at the end. H. oblonga ; in
salt water ; 1. 1-125". (Kent, In/us. 501).

HELICOT'RICHUM, Nees. 'See HELI-

COSPORIUM.

HELIOPEL'TA, Ehr.— A genus of Dia-
tomacese.

Char. Frustules single (?) ; valves cir-
cular, with imperfect radiating septa, the
alternate intermediate portions of the valve
being depressed; markings absent in the
centre, but as many large submarginal
apertures (?) present as there are rays, and
numerous erect opposite submarginal spines
on each side. The spines connect the pairs
of young frustules.

H. metii. Frustules with six septa and
rays, three of the intervals raised and coarsely
cellular, the alternate ones impressed with
fine decussating lines, the limb of the ra-

diate margin broad ; marginal spines in the
middle of each cellular interval one or three,
in the others two or four ; umbilical star
slightly angular; diameter 1-370". Ber-
muda.

H. Leeuwenhoeckii, PI. 25. fig. 4. Three
other species, with a different number of

The different appearances of the markings
upon the elevated and depressed portions of
the valves evidently arise from the existence
of the ordinary depressions seen naturally by
oblique and direct light.

BIBL. Ehrenberg, Berl. Ber. 1844, 262 ;
Greville, Mic. Tr. 1866, vi. 5 (new so.).

HELMIN'THOSPO'RIUM, Link. -A
genus of Dematiei (Hyphomycetous Fungi),
growing on rotten wood &c., of which nu-
merous species are found in Britain. Tulasne
regards this genus as consisting of stylo-
sporous forms of Sphaeriacei. Currey refers
to this genus Corda's Dactylium (DENDRY-
PHIUM) fumosum. The mycelium is often
somewhat gelatinous or indistinct ; on it
arise (often aggregated) erect, rigid, septate
filaments (fibres), on the summits of which
stand large, often club-shaped septate spores.
British species :

H. macrocarpum, Greville (Crypt. Fl. pi.
148. fig. 1).

H. subulatum. Nees (Nova Acta. ix. pi, 5.
fig. 13).

H. Clavariarum, Desmazieres (Ann. Sc,
Nat. 2 ser. ii. pi. 2. fig. 2).

H. velutinum, Link (Grev. Crypt. Fl.
pi. 148. fig. 2).

H.fusisporium, Berk. (Br. Flora, vol. ii.
part 2. 336).

H nanum, Nees (Nova Acta, ix. pi. 5.
fig. 13 B ; System, fig. 65).

H. simplex, Kunze (Nees, /. c. fig. 11).

H. Tilice, Fr. (Berkeley, Ann. N. H. vi.
pi. 13. fig. 18).

H. folliculatum. Corda (Ic. Fung. i. pi. 3
fig. 180).

H. obovatum, Berk. (Ann. N. H. vi. pi. 13.
fig. 19) ; on old wet planks.

H. delicatulum, Berk. (I. c. fig. 20) ; on
stems of Uinbelliferae.

If. Smithii, Berk, and Broome (Ann. N. If.
1851, vii. pi. 5. fig. 5).

If. turbinatum, Berk, and Br. (1. c. fig. 6).

H. Rousselianum, Montague (Ann. /Sc.
Nat. 3 «Sr, , xii. 300).

H. stictitum, Berk, and Br. (Ann. N. If.
1854, xiii. pi. 15. fig. 10).

BIBL. Berkeley, Br. Fl. iii. pt. 2, 336 ;
Fries, Syst. iii. 354, and Sum. Veyet. 500

HELMINTHOSTACHYS. [ 385 ]

HEMP.

(1849); Currey, Qu. Mic. Jn.v. 115 j Tulasne,
Ann. Sc. Nat. 4 ser. v. 109.

HELMINTHOS'TACHYS, Kaulf.— A
genus of Ophioglossaceous Ferns, distin-
guished by the complex spikes bearing
crested sporanges.

Fig. 314.

Fig. 315.

Helminthostachys zeylanica.

Fig. 314. Fragment of a spike with, sporanges.
nified 10 diams.

Mag-

Fig. 315. A portion still more magnified (20 diams.).

HELVEL'LA, L.— The typical genus of
Helvellacei.

Several species occur in this country,
amongst which H. lacunosa and H. erispa
are esculent.

BIBL. Fr. Syst. Myc. vol. ii. 13 ; Berk.
Outl. 358 ; Hooker, Syn. 447.

HELVELLA CEI.^-A family of Asco-
mycetous Fungi, comprised in Discomycetes,
approaching the Hymenomycetes in outward
form, but distinguished at once by their
fructification. See ASCOMYCETES, HEL-
VELLA, SPATHULARIA, LEOTIUM, STICTEI,
PROPOLIS.

HEMELYT'RA.— The anterior pair of
wings of the Heteropterous division of the
Hemiptera. See INSECTS.

HEMERO'BIUS, [Linn.— A genus of
Neuropterous Insects.

Hemerobius (Chrysopa) perla, one of the
lace-winged flies, has very thin, transparent,
and beautifully netted iridescent wings, in
which the circulation can be well observed ;
the wings also exhibit well the tracheae in
the veins. The larva feeds upon Aphides.

BIBL. Westwood, Intr. ; Bowerbank,
Entom. Mag. iv.

HEMIAU'LUS, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules single, compressed, sub-
quadrate, with two tubular processes on each
side, the ends of those (the shorter) on one

side being open, the others closed ; not con-
stricted at the sides.

H. antarcticus (PI. 25. fig. 3).

BIBL. Ehrenberg, Berl Ber. 1844, 199 ;
Greville, Ann. N. H. xvi. 5 j id. Mic. Tr.
1865, 26, 52, 101.

HEMIDIN'IUM, Stein.— A genus of
Cilio-flagellate Infusoria: free, flagellum
single ; a fringe of cilia in a groove exten-
ding halfway round the body. H. na-
sutum. yellow; freshwater. (Kent, Infus.
442.)

HEMIDIS'CUS, Wall. — A genus of
Diatomacege.

Char. Fr. free; valves arcuate, with a
median marginal inferior nodule ; areolation
hexagonal, radiate.

H. cuneiformis. From Salpce, Bay of
Bengal and Indian Ocean.

BIBL. Wallich, Mic. Tr. 1860, viii. 42

HEMILEI'A, Berk.— A genus of Ure-
dinese (Hynodermous Fungi), characterized
by the meniscoid spores, which are smooth
within, but strongly granulated without. H.
vastatrix, the Coffee-fungus, is extremely
destructive to the Coffee-plants, forming
orange-brown spots upon the leaves. One or
two other Rubiacese are attacked by a
distinct species. In germination, a form of
Penicillium has often been developed, but
this is probably accidental.

BIBL. Berk. & Br., Jn. Linn. Soc. xiv. 93 ;
Dyer, Qu. Mic. Jn. 1880, xx. 119 (figs.) ;
Abbay, Jn. Linn. Soc. xvii. 176; Ward,
Mic. Jn. xxii. (figs.).

HEMIONI'TIS, Linn. — A genus of
Grammitideae (Polypodiaceous Ferns), with
a very elegant reticulated arrangement of
the sori.

Eight species ; exotic. (Hooker, Syn. Fil.
398.)

HEMIOPH'RYA.— A genus of Acine-
tina (Kent, Inf.}.

HEMIP'TfiRA.— An order of INSECTS.

HEMIP'TYCHUS, Ehr. See ABACH-

NOIDISCUS.

HEMITE'LIA, Presl— A genus of Cya-
thseous Ferns. Exotic. (Hook. Syn. 27.)

HEMIZOS'TER, Ehr.— (Ehrenberg, Ber.
Berl. Ak. 1844, 199).

HEMP. — The orclinary name of the fibre
of Cannabis sativa, consisting of the liber-
fibres of this plant (PI. 28. fig. 6). It is
applied to some other substances used for
the same purposes, e. g. Manilla hemp (the
fibre of MTJSA) &c. See TEXTILE FIBRES
and LIBER.

2c

HENDEKSONIA.

[ 386 ]

HEPATIC^E.

HENDEBSO'NIA, Berkeley (Sporoca-
dus, Corda, in part). — A genus of Sphsero-
nemei (Stylosporous Fungi), interesting as
having furnished one of the earliest dis-
covered examples of two forms of fructifica-
tion, leading to the abolition of the distinction
between Coniomycetous and Ascomycetous
Fungi (CONIOMYCETES). Berkeley has
seen two conditions of spores in H. muta-
bilis, and states that Fries informs him of

Fig. 316.

Hendersonia.

Spores on the perithecium.
Magnified 200 diama.

the observation of asci and septate naked
spores (stylospores) conjointly in Hendersonia
Syringee. Several British species have been
described. They form dark spots or patches
on the stems of herbs or twigs of trees, — the
dark matrix having a perithecium excavated
in it, lined by a gelatinous stratum, on which
stand stalked fusiform septate spores (fig.
316).

H. elegans, Berk. (PI. 27. fig. 11) (Ann.
N. H. 1840, vi. pi. 11. fig. 9). On the culms
of reeds.

H. macrospora, Berk, and Broome (/. c.
2nd ser. v. 373). On dead twigs of Phi-
ladelphus.

H. arcus, Berk, and Br. (/. c.). On Box
twigs.

H. mutabih's, Berk, and Br. (/. c.).
dead twigs of Plane.

H. polycystis, Berk, and Br. (I. c.).
dead twigs of Birch.

H. macropus, Berk, and Br. (/. c.).
dead leaves of Carex.

H. typhoidearum, Desmazieres (Ann. Sc.
Nat.S se"r.xi. 344). On dead stems of Typha,
&c.

H. Stephensii, Berk, and Br. (Ann. N.
H. 2 ser. viii. 95). On dead stems of Pteris
aquilina.

H, fibriseta, Berk. (Hooker's Jn. JBot. iv.
43). On birch planks.

On
On

On

BIBL. Berkeley, and Berk, and Broome,
Ann. N. H. iv. 43 ; Hooker's Jn. of Sot. iii.
319 ; Fries, Sum. Veg. 416 ; Tulasne, Ann.
Sc. Nat. 4 ser. v. 115.

HEPAT'KLE.— An order of Muscales
(Cryptogamous Plants), consisting of plants
of small size, varying much in structure,
inhabiting damp spots on the ground, rocks,
or trees, or floating on water.

The vegetative structure of the lowest
forms consists simply of a patch of green
membrane, spreading over the ground,
composed of a single (Anthoceroa Itevis) or
double (Sphterocarpus terrestris) layer of
cells containing chorophyll. In Marchantia
(see MARCHANTIA) there is an advance ; the
frond not only exhibits more definitely cha-
racterized lobes, but also a considerable
thickness, and a complexity of internal
structure, since it possesses an epidermis
investing both surfaces, and containing
stomata on the unper (see STOMATA). The
lower epidermis is also provided with nu-
merous radical hairs (see HAIBS and SPIRAL
STRUCTURES). Fimbnaria (fig. 318) and

Fig. 317.

Fig. 318.

Fimbriaria fragrans.

Fig. 317. Lobe of a frond. Nat. size.
Fig. 318. Section of frond, showing two immersed
antheridia. Magnified 40 diams.

Lunularia (fig. 319), &c., likewise possess
thick cellular fronds. In Riccia the frond
also presents a reticulated upper face pro-
vided with stomata; but the form of the
entire frond is usually elongated and bifur-
cated, and a slight groove runs along the
middle line, almost like a mid-nerve. This
central line exhibits a difference in the in-
ternal cellular structure, since it is composed
of elongated cells, while the surrounding
green substance is composed of spherics!
cells, such as constitute the entire mass
enclosed between the upper and lower epi-
dermis of the frond of Marchantia. The
groove on the upper face (of Hiccia) corre-
sponds to a rib on the lower face, from
which arise most of the radical filaments.

HEPATIC^E.

[ 387 ]

HEPATIC^E.

while they are scattered indiscriminately
over the lower face of Marchantia ; and from
this line also arise the little bodies resem-
bling minute leaves, called amphigastria. If
we suppose the frond of Riccia elongated
and the mid-nerve more strongly marked,
we have the likeness of Bhjttia Lyelli (fig.
62, p. 106) ; while if this latter were notched
down to the rib at intervals along each side,
•we should have the stem with two parallel
rows of leaves, as in the Jungennannieae.

Fig. 319.

Lunularia vulgaris.
A frond in fruit. Nat. size.

The line of insertion of the leaves is
seldom exactly parallel with the axis of the
plant, and very rarely at right angles. In
most cases it is more or less oblique, and
the obliquity is in reverse direction at the
two sides of the stem, so that the lines of
insertion of two succeeding leaves would
meet, if prolonged across the stem, in the
form of a V (fig. 320).

The leaves are very frequently imbricated,
and they overlap in two ways : either each
leaf covers with its lower edge a little of the
leaf below it, or each leaf overlaps a little
of the base of the leaf above it. In the first
case, the leaves are called succubous (fig.
320), in the second incubous (fig. 321). The
leaves vary much in form, and are often
deeply toothed or bilobed, and form exceed-
ingly elegant objects under the microscope.
The leaves are accompanied in many cases,
chiefly in the Jungermannieae, by stipule-
like leaflets, called ampliiyastrid) situated at
the underside of the stem.

These plants are reproduced by dust-like
grains called spores, by minute cellular no-
dules called gemmce, and by innovations, i. e.
new lobes growing out from the margins of
the old fronds, or buds in the axils of leaves,

or on confervoid branches set out from the
stem.

The gemmceof Marchantia polymorpha are
produced in elegant membranous cups, with
a toothed margin, growing on the upper
surface of the frond, especially in very damp
and imperfectly lighted situations ; they are
little cellular nodules at first attached by a
stalk, and at a certain period fall off and
grow up into a new frond. (See MABCHAN-
TIA.)

Fig. 320.

Fig. 321.

Fig. 320. Eadula complanata. Magn. 5 diama.
Fig. 321. Plagiochila undulata. Magn. 5 diams.

The spores are produced in sporanges or
capsules, the formation of which is preceded
by special anatomical and physiological
phenomena demonstrating the existence of
distinct sexes in these plants. The organs
which represent the anthers of flowering
plants are called antheridia; those which
represent the ovules, and produce the spore-
cases, are called archegonia or pistillidia.
The antheridia are small globular or oval
bodies, more or less stalked, which in the
Jungermannieae are composed of a double
layer of cells forming a membranous sac,
which, when ripe, bursts and discharges
numerous minute globular cellules, each of
which again bursts and discharges an ex-
tremely small filament, which moves about
actively in water (figs. 322 & 324). These
organs mostly occur in the same situations
as the archegonia ; and in some of the fron-
dose forms, such as Anthoceros, Riccia,
Fimbriana (fig. 318), &c., they are im-
bedded in the substance of the frond; in
others, as in Marchantia, they are immersed
in the upper part of special male stalked
2 c 2

HEPATIC^E.

[ 388 ]

HEPATIC^E.

receptacles (see MARCHANTIA) ; in the leafy
forma they are free in the axils of the
leaves (fig. 323).

Fig. 322.

Fig. 323.

Fig. 324.

Haplomitrium Hookeri.

Fig. 322. Axillary antheridia. Magn. 30 diams.

Fig. 323. Fragment of wall of antheridia ; the reni-
form loose cells belong to the inner layer. Magn. 200
diams.

Fig. 324. Spermatozoids from ditto. Magn. 200 diams.

Fig. 325. Fig. 326. Fig. 327.

Marchantia polymorpha.

Archegonia in various stages.

Magnified 100 diameters.

The arcfagonia or pistillidia are likewise
developed in various places, indicated here-
after in the tabular view of the families.
They consist of a kind of flask-shaped cellu-
lar case (figs. 325 to 827), enclosing at first
a single cell (embryonal cell), which subse-
quently grows into a sporange, apparently
after one or more of the spiral filaments of
the antherids have come in contact with it,
by passing into the neck of the flask-shaped
sac (epigone}. The embryonal cell becomes

increased by cell-division into a globular
cellular mass, which acquires various forms
in the different genera and families. The
epigone enlarges for a long time with the
growing capsule, completely enclosing it
(fig. 328) ; but after a time the latter bursts

Fig. 328.

Haplomitrium Hookeri.

Young sporange enclosed in the epigone.

Magnified 20 diameters.

through the top of the epigone, which thus
forms a kind of sheath round the base of the
sporange or its stalk, and is called the vagi-
nule. The epigone may tear irregularly, so
as to form an irregular vaginule or calyx, or
regularly, so as to present a circle of teeth ;
or it may be slit horizontally in a circle, and
half of it carried up by the sporange, which
it thus surmounts as a hood or calyptra.
This epigone is sometimes surrounded by
another envelope called the perigone. This
originates at a later period and in a different
way, since it gradually springs up as a cir-
cular sheath around the base of the epigone,
and by continued growth comes to surround
it as a kind of cup, like the corolla of a
flower (fig. 320). In Marchantia, only one
archegone is found in each perigone; the
perigones of Juugermannieae always enclose
several, but only one is developed into a
sporange. In some kinds, as Sarcoscyphus,
there are always several archegones in a
perigone, and two or three produce spo-
ranges. Sometimes the archegones, with or
without perigones, are solitary; more fre-
quently they are in groups. Whether soli-
tary or grouped, they may have a further
envelope composed of slightly modified
leaves, free or confluent together ; these are
the perichcetial leaves, and constitute the
perichcete. When both perichcete and peri-
gone exist, it is easy to determine which is
which; but when only one exists, the history
of development alone gives the key; the

HEPATIC^.

[ 389 ]

HEPATIC^E.

perichsete is always developed before the
archegones it encloses, while the perigone,
as already stated, grows up round the arche-
gone during its development into a sporange,
being absent at the time of the first appear-
ance of that organ. In fig. 320 the base of
the pedicel is seen to rise out of a toothed
vaginule (calyx or epigone), which is enclosed
in a tubular perigone, outside of which are
two bilobed perichaetial leaves.

The sporange developed from the embry-
onal cell of the archegone varies much in
its perfect condition. In Jungermanniese it
is mostly an oval body borne on the extre-
mity of a delicate thread-like stalk spring-
ing out of the ihiginule (fig. 320). The oval
body splits down from the summit, when
ripe, into four valves, which spread open
more or less in the form of a cross (figs.
320-1), or bursts irregularly. The cells of
the valves exhibit very elegant spiral-
fibrous structure, like that of the walls of
anthers (see SPIRAL STRUCTURES). This
kind of sporange discharges minute spores
(see SPORES) and elaters, slender tubular
cells containing a spiral filament (PI. 40.
fig. 38), both forming very interesting
microscopic objects.

In the different frondose forms the spo-
ranges present very varied conditions. The
archegones of ANTHOCEROS send up a fili-
form sporange, which is two-valved and
contains a columella (fig. 24, p. 58). In
TARGIONIA and some others the capsule is
almost sessile, and bursts irregularly. In
RICCIA, where the archegones are imbedded
in the frond, the sporange is a sessile globose
body, with the calyptra adherent, never
bursting regularly, but emitting the spores
by decay. In SPHJERO CARPUS, also, the
calyptra is permanent as a cellular sac, in-
side of which the sporange ripens into an
indehiscent globular body, emitting the
spores only by decay. In Marchantia, Fe-
gatella,Lunularict) 6rrtmo&&i,&c.,the arche-
gones are produced on fleshy receptacles
elevated upon stalks, and the sporanges
are formed on the underside of these
receptacles (fig. 219. {>. 317, figs. 330, 333,
335), which are of varied forms, &c. The
sporanges on these either burst by valves
(fig. 331), or by circumscissile dehiscence
throw off a lid, as in Fimbriaria (fig. 335).

The frondose forms do not all produce
elaters, and have not all the spiral fibres in
the cells of their walls. The exceptions
are the Ricciese; and the elaters of Antho-
ceros are rudimentary. In Marchantia the

Fig. 329.

Fig. 330.

Fig. 331.

Lanularia vulgaris.
Fig. 329. Section of a receptacle, unripe.
Fig. 330. More advanced sporange, emerged from the

epigone.
Fig. 331. A burst sporange.

Magnified 20 diameters.

Fig. 332. Fig. 333.

Grimaldia barbifrons.

Fig. 332. Fertile plant. Magn. 2 diams.

Fig. 333. Section of the receptacle, with an abortive
archegone on the left side, and a half-ripe sporange still
enclosed in the epigone on the right. Magn. 20 diams.

. 334.

Fig. 335.

Fimbriaria tenella.

Fig. 334. Eeceptacles with closed epigones. Magn
10 diams.

Fig. 335. Two perigones, one with the epigone closed,
the other with the teeth of the epigone open, showing
the bursting sporange. Magn. 20 diams.

elaters are highly developed (PI. 40. figs.
36, 37), also the spiral tissue of the valves

HEPATIC^.

L 390 ]

IIEEPETIUM.

of the capsules (PI. 40. fig. 35). TARGIONIA
has branched elaters.

The spores mostly have a double coat, but
not always (e. g. Marchantia) ; they germi-
nate by protruding a pouch-like process,
which becomes a filament, from which the
new fronds or leafy stems arise.

The peculiarities of the different groups
above referred to will be better understood
after reading the following characters.

Synopsis of tlie Families.

A. Vegetation frondose, i.e. leaf and stem
confounded.

ANTHOCFROTE^J. The vegetative por-
tion consists of a minute green membranous
or slightly fleshy body growing on damp
ground, not exhibiting any distinct mid-
nerve : it is at once known by its peculiar
fruits or sporanges, consisting of slender
stalk-like bodies springing up irregularly
from the upper surface of the frond, which
forms little sheaths (vaginules) around their
bases. These stalk-like fruits burst when
ripe, splitting down the middle from the
tip, and display a central bristle-like column
•(columella), to which adhere the minute
hair-like bodies (rudimentary elaters j which
are mingled with the spores.

MARCHANTTEJE. The vegetative portion
is here also a succulent leaf-like expansion,
mostly exhibiting a more or less lobed
form, and without any conspicuous mid-
nerves in the lobes. The fruits are more
complicated structures than those of Antho-
ceroteaB. From notches in the lobed frond
arise slender stalks terminating at the top
in an expanded structure (receptacle), re-
sembling in some cases a conical cap, in
others a star with a number of thick rays
like the spokes of a wheel, &c. The spores
are formed in membranous sacs attached on
the under surface of the cap or star-like
body, and they are accompanied by elaters of
considerable size exhibiting highly deve-
loped spiral bands. £he sporanges have no
columella, and burst at the tip with more or
lesa regular tooth-like valves.

IlicciEJE. Vegetative portion an exceed-
ingly delicate cellular leaf-like structure,
more or less lobed, with an evident inid-
' nerve. The sporanges are either imbedded
in the substance of the frond, or only ele-
vated on a very short stalk, and surrounded
by a membranous sheath derived from the
upper surface of the frond. The sporanges
have no columella and no elaters.

PELLIEJE. Vegetative portion a leaf-like
frond, mostly with an evident mid-neme,
from which arises the sporanges, consisting
of capsules, usually bursting by four valves,
more or less elevated on a thread-like stalk.
Sporange without a columella j spores ac-
companied by elaters.

B. Vegetation foliaceous, i. e. leaves and
stem distinct.

JUNGERMANNIE^. Vegetative portion a
thread-like stem clothed with green mem-
branous leaves more or less overlapping at
their bases. Sporanges springing from the
end of the stem, raised on more or less
evident stalks, bursting by four valves and
spreading in the form of a cross; spores
with elaters, which often adhere to the
valves of the sporange. The leafy stem of
Jungermannieae is generally readily distin-
guishable from that of the Mosses by the
mode of insertion of the leaves, which pro-
duces a peculiar flattened arrangement.

BIBL. Hooker, Br. Junger?nanni<e,18I6',
Bischoff, Nova Acta, xvii. 909, pis. 67-71,
1835; Entwickl. d. Lebermoose, Bot. Zeit.
xi. 113, Ann. Sc. Nat. 3 se"r. xx. 57 ; Lin-
denberg, Synops. Hepatic. 1814 ; Greenland,
Ann. Sc. Nat. 4 se"r. i. 5 ; Hofmeister, Vergl.
Unters. iib. Kryptog. 1851 ; Gottsche, Bot.
Zeit., Suppl. vi. 1858; Du Mortier, Hepat.
Europ. 1874; Carrington, Hepat. 1876;
Leitgeb, Leberm. 1879 ; Husnot, Hep. Gall.
1881.

f HERCOTHE'CA, Ehr.— A genus of fos-
sil Diatomacese.

//. mammillaris (PI. 18. fig. 31), the only
British species; diameter 1-810". Bermuda.

BIBL. Ehrenberg, Ber. d. Berl. Ak. 1844,
262 ; Kutzing, Sp. Ala. 27.

HERMAN'NIA, Nicolet— A genus of
Oribatea (Acarina). Cephalothorax without
ribs, soldered to the abdomen ; tarsi with
one claw. In moss. (Murray, EC. Ent. 221,
figs. ; Michael, Jn. Mic. Soc. 1880, 192.)

HERPE'TIUM, Nees.— A genus of Jun-
germannieae (leafy Hepaticae), distinguished
by the incubous bilcbed leaves not being
folded together, and by the obtusely three-
angled perigone. Two Brit, species :

H. reptans(Lepidozia, Dumortier). Leaves
squarish, acutely two- or four-toothed at
the end. Woods and shady places. Jung,
reptans, Hook. Br. Jung. pi. 75.

H. trilobatum (Mastigobryum, Nees).
Leaves ovate, three-toothed at the summit.
Moist alpine spots. J. trilobatum} Hook.
Br. Jung. pi. 76.

HERPETOMONAS.

[ 391 ]

HETEROSTOMELLA.

BIBL. Hooker, Br. Jung. I. c. ; End-
licher, Gen, Plant, nos. 472-9; Ekart, Syn.
Jung. pi. 3. figs. 21, 22.

ELERPETO'MONAS, Kt.— A genus of
Flagellate Infusoria.

Char. Free, elongate or vermicular,
highly flexible ; flagellum single.

H. muscce, in the intestine of the house-fly.
H. Lewisi (PL 53. fig. 18), in the blood
of Indian rats ; perhaps also in the blood
of the field-mouse and mole; 1. 1-1500".
(Kent, In/us. 245; Lewis, Qu. Mic. Jn.
1879.)

HETEROCORDY'LE, Allm.— A genus
of Hydroid Zoophytes, fam. Atractylidse.

If. Conybearei. On old shells ; marine.
Ireland.

BIBL. Allman, Ann. N. H. 1864, xiv.
59 : Hincks, Brit. Zooph. 107.

HETERODES'MUS, Brady.— A genus
of recent Ostracode Entornostraca, family
Cypridinidae ; subglobose, with the hinges
of the valves developed into large processes
at the dorsal angles.

H. Adamsii. Sea of Japan.

BIBL. Brady, Zool. Trans, v. p. 387.

HETERODIC'TYON, Grev.— A genus
of Diatomaceae.

Char. Fr. free, disciform ; disk with
radiate or scattered puncta in the middle
portion, and a ring of large intra-marginal
cellules.

H. Rylandsianum and H. splendidum.
Barbadoes deposit.

BIBL. Grev. Mic. Tr. 1863, iii. 66 (fig.).

HETEROMAS'TIX, Oik.— A genus of
Cilio-flagellate Infusoria; corresponding to
a Eugkna with two anterior flagella, one
trailing; and an anterior oral fringe of cilia.

H. proteiformisj in fresh water. (James-
Clark, Mem. Bost. Soc. N. H. 1868 ; Kent,
In/us. 463.)

HETERO'MITA, Duj.— A genus of Fla-
gellate Infusoria.

Char. Body globular, ovoid, or oblong,
with two filaments arising from the same
point in front — one, more delicate, and with
an undulatory motion, causing progression ;
the other thicker, and floating freely be-
hind, or adhering here and there to the
slide, so as to produce by its contraction
sudden motion backwards.

Distinguished from Anisonema and Hete-
ronema by the absence of a tegument, shown
by the glutinous appearance of the body,
the facility with which it adheres to other
objects and becomes drawn out, and the
presence internally of certain corpuscles

which can only have entered by vacuola
formed on the surface.

Found in both fresh and salt water, and
in fiush-macerations.

H. ovata=Bodo grandis, E. (PI. 30. fig.
18 a) ; among freshwater plants.

H. granulosa. Body globular, surface
granular; marine; length 1-2300".

. H. angusta. Body lanceolate, slightly
sigmoid; freshwater; length 1-980".

Other species.

BIBL. Bujardin, Jn/w«. 297; Kent, In/us.
290.

HETERONE'MA, Duj.— A genus of
Flagellate Infusoria, of the family Euglenia.

Char. Form variable, oblong, irregularly
expanded posteriorly ; with a slender flagel-
liform filament, and a thicker trailing, re-
tracting filament ; tegument obliquely stri-
ated.

Differs from Heteromita in the presence
of a tegument, and from Anisonema in the
tegument being contractile.

H. marina (PL 31. fig. 17). Filaments
longer than the body ; length 1-4300".

BIBL, Dujardin, Infus. 370; Kent, Inf.
430.

HETERO'PHRYS, Archer— A genus of
freshwater Rhizopoda. 2 species.

BIBL. Archer, Qu. Mic. Jn. 1869, ix. 267

HET'EROPUS, Newp. — A genus of
Acarina.

H. ventricosus occurs in the nests of An-
thophora retusa, living upon the larvae.
(Newport, Linn. Tr. 1850; Murray, EC.
Ent. 290, figs.)

HETEROSTEGI'NA, D'Orb.— A flat,
discoidal Nummuline Foraminifer, with
whorls rapidly increasing in breadth and
reticulated by the primary and secondary
septa of the narrow curved chambers and
their rectangular partitions. Living in the
Eastern Archipelago ; fossil in the Tertiary
beds, especially forming one stratum in the
island of Malta.

BIBL. Carpenter, Intr. For. 288 ; Jones,
Geol. Mag. ii. 151.

HETEROSTOMEL'LA, Reuss.— One of
the Textularian Foraminifera, in which the
chambers are at first set on alternately, but
not neatly, on either side of a straight axis,
and afterwards, growing in a single row, as
in Bigenerina, not only open terminally, in-
stead of laterally, but have a tubular, and
even a lipped, aperture, such as we see in
Uvigerina. Shell often prickly. Fossil in
the Chalk of Europe and America.

HETEROTRICHUS.

[ 392 ]

HDIANTOPHORUS.

BIBL. Reuss, Sitz. Ak. Wien, Hi. ; Parker
and Jones, Ann. N. H. ser. 4. ix. 21)8.

HETEROT'RICHUS, Donnadieu. — A
genus of Acarina, fani. Garnasea.

H. inaquarmatus. Hairs jointed, longer
than the body.

BIBL. Donnadieu, Jn. de TAnat. 1876
(Mn. Mic. Jn. 1877, xvii. 283, fig.).

HEWAR/DIA, Hook.=Adiantum, pt.

HEXAM'ITA, Duj.— A genus of Flagel-
late Infusoria.

Char. Body oblong, rounded in front,
constricted and bifid or indented behind;
four flagelliform filaments arising separately
from the anterior margin, the two posterior
lobes being prolonged into flexuous fila-
ments.

If. nodidosa (PI. 31. fig. 20). Oblong,
with three or four longitudinal rows of no-
dules ; motion vacillating ; length 1-1800".
In decomposing marsh-water.

H. inflata ; in decomposing infusions.

H. intestinalis. Fusiform, prolonged into
a bifid tail j length 1-2100' '. In the intes-
tines and peritoneal cavity of the Batrachia
and Tritons.

BIBL. Dujardin, Infos. 296 ; Kent, Inf.
318.

HILDENBRANDTIA, Zanardini. — A
genus of Nulliporous Corallinaceae (Flori-
deous Algae), containing one British species,
H. sanguined, Kiitz. : common, in the form
of a bright or dark red membranous crust,
at first circular, afterwards spreading irre-
gularly over smooth stones and pebbles.
Frond about 1-20" thick in the middle,
thinner toward the edges, and composed of
minute globose cells, partly vertical, partly
horizontal ; it is not stony. ' It has immersed
conceptacles, pierced by a pore (fig. 250,
p. 327), containing tetraspores and para-

le species occurs in alpine streams.

BIBL. Harvey, Mar. Alg. 110, pi. 14 C ;
Phyc. Brit. pi. 250 ; Kiitz. Phyc. Gen. pi.
78. fig. 5; Rabenhorst, Fl. Alg. iii. 408.

HI'LUM. — This name is applied to the
surface of attachment of the funiculus of
seeds, which is seen as a kind of scar, more
or less distinct. Sometimes it coincides
with the chalaza or organic base of the
seed, sometimes, where a raphe exists, it is
near the rnicropyle. (See OVULE.)

HIMANTHA'LIA, Lyngbye.— A genus
of Fucaceae (Fucoid Algae), remarkable for
the peculiar forms of the frond and recep-
tacle, the latter consisting of a repeatedly
forked strap-shaped cord from 2 to 10' long,

springing from the top-shaped frond, which
is about an inch high. The dark olive-green
thong-like H. lorea is common on rocky
sea-shores. The receptacle is pierced by
numerous pores leading to immersed con-
ceptacles resembling those of Fucus, con-
taining either parietal spore-sacs or antheri-
dia, the plants being dioecious. The centre
of the receptacle is filled with mucous
matter traversed by jointed filaments. The
antheridial sacs of Himanthalia are double,
and contain spermatozoids of flattened ovoid
or spherical forms, with an orange granule
and two cilia, like those of Pycnophycus
and Halidrys.

BIBL. Harvey, Mar. Alg. 20, pi. 2 B ;
Thuret, Ann. Sc. Nat. 3 se"r. xvi. 54 ; Gre-
ville, Alg. Brit. pi. 3 ; Engl. Bot. pi. 569.

HIMANTID'IUM, Ehr.— A genus of
Diatomaceae, cohort Eunotieae.

Char. Frustules resembling those of Eu-
notia, connected by their sides into a fila-
ment; striae transverse, parallel. Fresh-
water.

Kutzing describes thirteen species, some
of which are fossil ; Smith admits eight
British species, one doubtful.

H. pectinale (Fragilaria pect., Ralfs) (PI.
16. fig. 36). Frustules in side view nar-
rowed at the curved and rounded ends ;
one side slightly raised and flat, the other
slightlv excavated or flat ; striae evident ;
length 1-180*.

/3. Convex margin undulate or with two
indentations (fig. 36 b) = H. undttlatum, Sm.
Ralfs remarks a difference of form between
the newly-forming and the parent frustules,
the lateral margins of the former in front
view being rounded (fig. 36 c).

H. arcus. Fr. rectangular ; valves linear-
arcuate, ends rounded, subrecurved ; striaa
evident; length 1-300 to 1-132".

BIBL. Ehrenberg, Berl. Ber. 1840 ; Kut-
zing, Bacill. 36 ; Sp. Alg. 8 ; Ralfs, Ann.
N. H. xii. 107, xiii. 459 ; Smith, Br. Diat.
ii. 10.

HIMANTOPH'ORUS,Fabricius.— A ge-
nus of Infusoria, of the family Euplota.

Char. Head not distinct from the body ;
hooks numerous ; neither styles nor teeth
present.

Long curved hooks, almost in pairs, form
a broad band on the ventral surface, and are
the organs of locomotion ; also a row of cilia
extending from the mouth a considerable
distance backwards.

H. Charon (PI. 31. fig. 18, under view ;
fig. 19, side view). Body hyaline, plane,

HIPPAEOHIA.

[ 393 ]

HOLOPHRYA.

elliptical, anterior end somewhat obliquely
truncate; cilia small, hooks slender and
long. Marine. Length 1-180".

BIBL. Ehrenberg, In/us, p. 375.

HIPPAR'CHIA, Fabr.— A genus of
Lepidopterous Insects.

Char. Wings more or less rounded, mid-
dle longitudinal nerve of fore wings giving
off posteriorly four nerves ; antennae with
an elongate, compressed and curved club ;
head small.

H. Janira, the meadow brown butterfly,
in which the wings are brown, and the
anterior pair exhibit a blackish-brown round
spot with a white eye or centre, is common
in meadows. The paler scales of the anterior
wings (PL 1. fig. 9) were formerly used as
TEST-OBJECTS.

BIBL. Westwood, Introd. and Br. Butter-
flies.

HIPPOCRE'PIA.— An order of Polyzoa.

Distinguished by the crescentic or horse-
shoe-shape of the tentacular disk, and the
presence of an epistome. Freshwater.

Synopsis of the Families.

CRISTATELLID.&J. Polype-mass floating.

PLTJMATELLID^. Polype-mass rooted,
unjointed.

The family Paludicellidae, containing the
single genus Pahidicella, is usually placed
here ; but it properly belongs to the Infun-
dibulata, as the tentacular disk is circular
and entire, and the epistome absent.

See POLYZOA and URNATELLA.

HIPPOCREPI'NA, Parker.— A Lituo-
line Foraminifer, characterized by the horse-
shoe-shape of the aperture, due to the pre-
sence of a tongue-like process, as in Valvu-
lina. H. indivisa, from the Gulf of St.
Lawrence, is carrot-shaped.

BIBL. Parker, in Dawson, Canad. Nat.
1870.

HIPPOTH'OA, Lamx.— A genus of In-
fundibulate Cheilostomatous Polyzoa, of the
family Eucratiidae (Scrupariidae).

Distinguished by the confervoid, branch-
ed, creeping and adherent polyzoary, the
branches arising from the sides of the ellip-
tical cells, frequently anastomosing, and the
cells in one row.

H. catennlaria. Cells contiguous, orifices
oval. On shells in deep water.

H. divaricata. Cells remote, orifices round.

BIBL. Johnston, Br. Zooph. 291 ; Gosse,
Mar. Zool. 12 ; Hincks, Polyzoa, 256.

HIPPURA'RIA, Busk.— A genus of

Ctenostomatous Polyzoa. (Hincks, Poly-
zoa, 548.)

HIPPURIC ACID.— This acid occurs in
small quantity in human urine, especially
after a vegetable diet ; more largely in that
of the horse and other herbivora, as the ox,
the goat, the sheep, the hare, &c. j also in
that of some reptiles.

It is readily soluble in boiling water and
alcohol ; less so in cold water and in ether.

It crystallizes in prisms or needles (PI. 11.
fig. 18), belonging to the right rhombic
prismatic system, some of which bear re-
semblance to those of the ammonio-phos-
phate of magnesia, from which it is readily
distinguished by its solubility in potash or
hot water. It is sometimes obtained under
the same circumstances as benzoic acid, from
which it differs in its greater solubility in
ether, and in the thickness and solidity of
its prisms, those of benzoic acid being thin
and plate-like. Its crystals are beautifully
analytic; which property is deficient in those
of benzoic acid.

It may best be procured from cow's urine,
by boiling with slaked lime for some time,
filtering and supersaturating with muriatic
acid ; and it may be purified by repeating
the process and using animal charcoal.

HIRNE'OLA, Fr.— A genus of Tremel-
lini (Hymenomycetous Fungi), consisting of
gelatinous cup-shaped Fungi, horny when
dry, and clothed externally with short vel-
vety bristles. The hymenium is without
papillae, a character by which it is distin-
guished from Exidia, to which the species
were formerly referred. The Jews' Ear
(H. auricula Judce] is still sold by Herba-
lists as a remedy for affections of the throat,
the supposed virtues clearly depending on
the doctrine of signatures. One or two
species are extremely common in tropical
countries; and used as an article of food
in China.

BIBL. Fr. Summa, 340 ; Berk, Outl. 289

HISTOLOGICAL ANALYSIS. See
INTRODUCTION, p. xlii.

HISTOLOGY, or HISTIOLOGY, is the
theory of the structure of animal and vege-
table tissues in relation to their develop-
ment ; but the term is often applied to the
microscopic structure of tissues.

HIS'TRIO. — A genus of Hypotrichous
Infusoria (Kent, Inf.}.

HOLOPH'RYA, Ehr.— A genus of Hoi o-
trichous Infusoria, of the family Enchelia.

Char. Body covered with vibratile
cilia, oblong-ovate, cylindrical or globular,

HOLOSTICHA.

[ '394 ]

HOPLOPHOEA.

rounded or truncate in front ; no lips nor
teeth ; cilia arranged in longitudinal rows.

Ehrenberg admits six freshwater species ;
to these Dujardin, who places this genus in
the family Paramecia, adds one marine.

H. ovum, E. (PL 31. fig. 22). Body ovate,
subcylindrical, ends subtruncate ; internal
substance green : length 1-576 to 1-216' '.

H. brunnea, D. (PI. 31. fig. 21). Body
brown ; cylindrical, becoming globular when
distended with food, and then changing in
colour; length 1-120".

The encysting-process has been observed
in two of the species.

BIBL. Ehrenberg, Inf. 314; Dujardin,
Inf. 493 ; Cohn, Sieb. und Koll. Zeitschr.
iv. ; Stein, Inf. ; Kent, Inf. 498.

HOLOSTICHA.— A genus of Hypo-
trichous Infusoria (Kent, Inf.}.

HOLOTHURID'EA (Sea-slugs).— A fa-
mily of Echinodermata, of the order Pedi-
cellata.

Interesting to the microscopist, from the
presence of curious calcareous plates, &c.
existing in the integument.

See ECHINODERMATA.

HOLOTHYRUS, Gerv.— A genus of
Gamasea (Acarina).

H. coccinella is nearly as large as a lady-
bird (Coccinella), and is found in the Isle of
France.

BIBL. Gervais, Walckenaer's Apteres, iii.

HOMALOCOC'OUS, Kiitz.— A genus of
Confervoid Algae, consisting of cells united
into flat oblong irregular corpuscles, en-
closed in a spherical gelatinous sheath.

H. Hassallii ; green, size of a pea or nut ;
in stagnant pools. (Rabenh. Fl. Alg. 69.)

HOMCEOCLA'DIA, Ag.— A genus of
Diatomacese.

Char. Frustules those of Nitzschia, ar-
ranged in tufts within gelatinous tubes,
which form a filiform, usually branched
frond. Marine.

H. Martiana, Ktz. (H. anglica, Ralfs)
(PI. 19. fig. 15 : «, portion of frond ; b, part
of a filament containing two frustules ; c,
front view of single frustules, with endo-
chrome ; d, side view of empty frustules).
Frond simple or dichotomously divided,
rugose ; entire plant 1 to 2" high.

H.jiUformis. Frond linear, simple, tufts
containing three or four frustules.

H. sigmoidea. Frond linear, simple; frus-
tules sigmoid.

Rabenhorst describes 8 European species.

BIBL. Kiitzing, Bacillar. 110, and Sp. Alg.
97; Ralfs, Ann. N. H. 1845, xvi. 109;

Smith, Br. Diat. ii. 80; Rabenhorst, Fl.
Alg. i. 166.

HOM'OPUS, Furst.— A genus of Hypo-
pidae (Acarina). H. elephantis, found on
the dried skin of an elephant, = the hypopial
nymph of Acarus domesticus, JVIegnin.
(Fiirstenberg, Kratzmilben, 222 ; Murray,
EC. Ent. 253 (fig.); Megnin, Paras. 147.)

HOOF. — The hoofs of animals consist of
the same structure as horn.

HOOKE'RIA, Smith.— A genus of Hyp-
noid Mosses.

Two species, on moist banks and wet
rocks.

BIBL. Wilson, Bryol. Brit. p. 415.

HOP. — Thehop ^lant(HumulusLupulus)
is remarkable for the glands containing the
resinous secretion imparting the aromatic
odour. These occur on the lower face of
the leaf, upon the calyx, and above all, on
the scales of the fruit and the seed-coat.
They have been examined by Meyen and
others, mostly recently by Personne. They
are little stalked cups (PI. 28. fig. 14) com-
posed of a single layer of cellular tissue,
concave above at first ; but as the secretion
increases in quantity, the cuticle becomes
detached in a plate from the upper surface,
except at the rim of the cup, and is pushed
up so as finally to form a convex papilla on
the top, like the nut projecting from an
acorn-cup. The secretion appears to be
formed in the cells, and poured out beneath
the cuticular pellicle, which is marked with
lines corresponding to the side-walls of the
cells. Solution of potash and alcohol clean
away the resinous secretion, and render the
structure clear. When the fresh glands are
placed in water, they swell, and finally burst,
the cuticular lid usually separating by a cir-
cumscissile dehiscence.

The hop is subject to a peculiar mildew,
a minute fungus, for which see EBYSIPHE
( Sphcerotheca).

BIBL. Meyen, Secretions- Organe d. Pflan-
zen, 38, pi. 5. figs. 17-21 ; Personne, Ann.
Sc. N. 4 se-r. i. 299, pi. 17.

HOPLITOPH'RYA, St.— A genus of
Holotrichous Infusoria.

Char. Ovate or elongate, mouthless, with
a ventral anterior band or one or more
hooks. Internal parasites. Seven species :
in the intestine of Lumbrici, Planarice, &c.
(Kent, Inf. 571.)

HOPLOPH'ORA, Koch.— A genus of
Oribatea (Acarina).

Char. Body and general habit those of
Galumna, but no wing-like appendages to

HORMIDIUM.

[ 395 ]

HORN.

the pseudo-thorax; cephalothorax articu-
lated to the abdomen, folding upon the
body.

Two species ; on decaying fir-wood and

roots.

BIBL. Gervais, Walckenaer' s Apteres, m. ;
Claparede, Zeit. luiss. Zool. xviii. ; Murray,
Ec.Ent. 2-2-2-, Jti. Mic. Soc. 1880,177.

HORMIDIUM.— The group of species
of Ulothrix growing upon moist earth.

HORMIS'CIA, Aresch.— A genus of
Confervoid Algae, close to Ulothrix j with
the filaments jointed, usually simple, but
sometimes emitting ramules; cells with
thick, often lamellar walls ; propagation by
macro- and inicro-gonidia. Fresh and salt
water. (Rabenh. Fl. Alg. iii. 361.)

HORMOS'PORA, Breb.— A genus of Pal-
mellaceaa (Confervoid Algae), with a frond

Fig. 336.

Fig. 337.

Hormospora transversalis.
Fragments of gelatinous filaments, with the cells

grouped in fours.
Magnified 350 diameters.

consisting of simple or branched gelatinous
confervoid cords enclosing rows of oval or
spherical cells ; they are found floating
among Confervas or other aquatic plants,
and appear to the naked eye like greenish
filaments. These plants do not appear to
consist of septate filamentous tubes like the
Confervse, but of rows of individual cells
imbedded in a filiform gelatinous tube
(fig. 336), analogous in its nature to the
gelatinous coat investing the linear rows ol
cells of Hyalotheca, &c. The cells multiply
by transverse division, the rows thus becom-
ing elongated; these cells contain green
contents arranged in a granular, lamellar,
or radiating form. Brebisson describes ob-
scurely another mode of increase, in which
the " endochrome becomes concentrated anc
organized into vesicles or zoospores. Th
corpuscles then become larger ; and the fila-
ment becoming as it were dislocated, the
corpuscles group themselves in several rows
and without regular form " (fig. 337). In

H. transversalis there is an especial tendency
to a grouping of the cells in fours. Five
species have been described j 1 and 3 are
known as British.

H. mutabilis, Breb. Filaments simple ;
cells ovoid or subspherical j cell-contents
lamellar ; freshwater. Breb. Ann. Sc. Nat.
3 ser. i. pi. 1. fig. 1.

H. transversalis, Breb. (figs. 336, 337).
Filaments simple ; cells ovoid or fusiform,
transverse ; contents granular j freshwater.
Breb. I. c. fig. 2.

H. ramosa, Thwaites. Filaments
branched ; cells oval or spherical j contents
radiated. In a pool to which salt water
had access. Harvey, Phyc. Brit. pi. 213.

BIBL. Brebisson, Ann. Sc. Nat. 3 ser. i.;
Harvey, Br. Mar. Alg. 235, pi. 27 B, Phyc.
Brit. pi. 213 ; Nageli, Einzell. Alg. 7, pi. 3.
fig. B ; Rabenhorst, Fl. Alg. iii. 48.

HORN. — The horns of animals are of
three kinds, — those composed of bone, those
consisting of epidermic formations, and
those in wThich both are present. The former,
properly called antlers, agree in minute
structure with bone, and therefore require
no special notice. The horn of the rhino-
ceros may be taken to represent the structure
of the second kind. It consists of an aggre-
gation of horny fibres, each of which is made
up of a series of concentric layers. These
layers are composed of cells tangentially flat-
tened, and sometimes containing pigment.
The cells may be separated by macerating
the horn in solution of potash. Cracks
filled with air are frequently visible between
the layers. The centres around which the
laminae are arranged probably correspond to
papillae of the cutis. The horn of the
buffalo agrees essentially in structure with
that of the rhinoceros.

The third kind of horn is exemplified by
that of the cow. In its centre is a process
of bone, surrounding and extending beyond
which is the proper horn, consisting of con-
centric layers, in the natural state composed
of flattened, irregular, angular, nucleated
cells (PI. 22. fig. 29 «), which assume their
primitive forms under the action of potash
(6) ; some of them contain pigment (d).
Between the laminae, cracks containing air
are also met with (f).

Sections of horn made at various angles to
the axis, form very beautiful polarizing ob-
jects ; the gorgeous colours seen in those of
rhinoceros's horn cannot be excelled, nor can
drawings represent them faithfully (PL 39.
figs. 37, 38). The horn of the buffalo

HORNBLENDE.

[ 396 ]

HYDATINJEA.

also forms an interesting object of the same
kind.

BIBL. Bonders, Mulder's Phys. Chem.-,
Owen, Brandos Diet., art. Cornua.

HORNBLENDE. See ROCKS.

HOR'NERA, Lam. — A genus of Cyclo-
etomatous Polyzoa. 2 species. (Hincks,
Polyzoa, 467.)

HORSE-LEECH. See HJEMOPIS.

HUXLEY'A, 01. & Lachm.— A genus of
Hypotrichous Infusoria, of the family Er-
vilina. Two species :

H. sulcata. Body greatly compressed ;
cuticle with oblique furrows. Bergen.

H. crassa. Body scarcely compressed,
almost as thick as broad, thickest behind ;
cuticle smooth ; length 1-1250". Bergen.

BIBL. Clap. & Lachmann, Inf. 290.

HUXLEY' A, Dyster.— A genus of Chei-
lostomatous Polyzoa. H. fragilis, Tenby.
(Hincks, Polyz. 26.)

HYALODIS'CUS, Ehr. = CYCLOTELLA,
Kiitz. in part.

H. lcevis=Cyclotellalams', H. patagonica
= Cyl. patagon.', H. subtilis, Bail., with
extremely tine dots, is used as a test-object.

BIBL. Ehrenberg, fieri. Ber. 1845, 78 &
155 ; Kutzing, Sp. Alg. 20.

HYALOM'MA, Koch.— A genus of
Ixodea (Acarina), with the eyes clear, dis-
tinct and conical. Three or four species,
occurring in the Caucasus and Spain.
(Koch, Uebers. ; Murray, EC. Ent. 196,
figs.)

HYALOP'TERUS, Koch.— A genus of
Aphidse. Differing from Aphis chiefly in
the shortness of the tail and nectaries, and
the oval, often linear form of the body. Six
species : found on the plum, the reed, the
moss-rose, the columbine, Silene inflata,
and Eriophorum. (Buckton, Aphides, Ray
Soc. ii. 109.)

HYALOSI'RA, Kiitz.— A genus of Dia-
tomaceae.

Char. Frustules compound, rectangular,
tabular ; with alternate vittse, interrupted
in the middle, and connected with those of
the opposite side by fine lines ; lowermost
frustule attached by a stipes which is affixed
to one angle. Marine.

The fine lines at the end of the vittas
give the latter a forked appearance. The
frustules are often partly separated, so as to
be connected with each other by one angle
only.

Four species, probably forms of Tetracy-
clus.

H. rectangula (PI. 17. fig. 1). Stipes

short, frustules subconcatenate, in front view
subquadrate ; rectangular ; length 1-1380".

BIBL. Kutzing, Bacillar. 125 ; Sp. Alg.
115 ; Rabenhorst, Fl. Alg. i. 306.

HYALOSPHE'NIA.— A genus of Rhi-
zopoda (Bronn, Klass. &c., pi. i. fig. 18).

HYAXOTHE'CA, Ehr.— A genus of
Desmidiaceae.

Char. Cells united into an elongated,
cylindrical filament, which is surrounded
by a gelatinous sheath ; cells in front view
slightly constricted, so as to give the margins
a crenate appearance ; or having a grooved
rim surrounding one end, and forming a
bidentate projection ; end view orbicular.

The filaments are not twisted, and are
always of the same apparent breadth. Spo-
rangia orbicular, smooth.

H. dissiliens (PL 14. fig. 1, front view of
filament; 2, end view). Filament fragile,
margins crenate ; breadth of filament 1-1300
to 1-800". The transparent sheath of this
beautiful object is so delicate as to be easily
overlooked. Sporangia (fig. 314) situated
within the connecting tube.

Not uncommon in clear boggy pools.

H. mucosa. Filament scarcely fragile;
joints not constricted, surrounded at one
end by a minute furrowed rim, forming in
the front view a bidentate projection ;
breadth of filament 1-1250 to 1-1100".

The furrowed rim of each cell is on the
same side as that of the contiguous cell.

BIBL. Ralfs, Brit. Desmid. p. 51.

HYDATI'NA, Ehr.— A genus of Rota-
toria, of the family Hydatinaea.

Char. Eyes absent ; jaws two, teeth nu-
merous, free ; foot forked.

H. senta (PI. 43.^fig. 37 ; fig. 38, teeth).
Body conical, hyaline ; margin of rotatory
organ ciliated ; foot robust ; aquatic ; length
1-48 to 1-36".

This animal forms a favourable subject
for the examination of the typical structure
of the Rotatoria, and is that which Ehren-
berg used as the basis of his investigations
upon their organization.

H. brachydactyla. Segments of foot
short ; body suddenly narrowed at the base
of the foot; aquatic; length 1-144".

BIBL. Ehrenberg, In/us. 412; Cohn,
Sieb. 8f Koll. Zeitschr. vii'.

HYDATINJE'A.— A family of Rota-
toria.

Char. Neither carapace nor enveloping
sheath present ; rotatory organ multiple, or
more than bipartite.

18 genera.

HYDNOGLOEA.

[ 397 ]

HYDRA.

Eyes absent,

"So teeth Enteroplea.

Teeth present,

Jaws with numerous teeth Hydatina.

,, with a single tooth Pleurotrocha.

Eyes present,
Eye single,

"Eye frontal Furcularia.

„ cervical,

Foot styliform Monocerca.

„ forked,

Frontal cilia, no hooks nor

styles Notommata.

Frontal cilia, styles present... Synchcsta.

„ hooks Scaridium.

Foot absent ; with cirrhi or fins. Polyarthra.
Eyes two,
Eyes frontal,

Foot forked Diglena.

„ styliform,

With cirrhi Triarthra.

Without cirrhi Battulus.

Eyes cervical Distemma.

Eyes three,
Eyes not stalked,

Eyes cervical Triophthalmue.

Two eyes frontal, one cervical . Eosphora.
Two frontal eyes stalked, one cer-
vical not stalked Otoglena.

Eyes more than three in a single

group Cycloglena,

Eyes more than three in two groups Theorus.

BIBL. Ehrenberg, Infus. p. 410.

HYDNOGLCE'A, Berk. & Ourr.— A
genus of Tremelloid Fungi. H. gelatinosa
occurs in this country occasionally on very
rotten pine wood. (Berk. & Br. Ann. N.
H. 1871, vol. vii. 429.)

HY'DRA, Linn. (Freshwater Polype).—
A genus of Hydro id Zoophytes, of the family
Hydridee.

Char. Locomotive, single, naked, gelati-
nous, subcylindrical, but very contractile
and variable in form ; the mouth surrounded
by a single row of filiform tentacles. Pro-
pagation by the formation of gemmae, and
ova upon or within the substance of the
body of the animal.

Hydra viridis (PI. 41. fig. 21, adhering to
the radicles of duck- weed (Lemna)}. Body
leaf-green, cylindrical or insensibly narrowed
towards the base ; tentacles 6 to 10, shorter
than the body, narrowest at their origin.

Common in ponds and still waters.

H. vulgaris. Body orange-brown, yel-
lowish or red, cylindrical ; tentacles 7 to 12,
as long as or longer than the body, tapering
to the free ends.

In weedy ponds and slowly running
waters; common.

H. attenuata. Body pale olive-green,
attenuated below ; tentacles pale, consider-
ably longer than the body. In ponds ; rare.

H. fusca (oligactis). Body brown or
greyish, lower half suddenly attenuated ;
tentacles 6 to 8, several times longer than
the body. Still waters j rare.

The characteristic forms of the body can
only be j udged of when fully extended in
search of prey ; for when the animals are
touched, shaken, or in any way disturbed,
the body assumes very variable forms,
becoming rounded, ovoid, &c.

The structure of the body of Hydra has
been much investigated and discussed. By
some it has been regarded as consisting of
three layers — an internal and external coat,
and an intermediate muscular layer. The
true structure, however, has been pointed out
by Ecker. This author regards the animal
as consisting of sarcode or protoplasm, and
neither furnished with an outer nor an inner
coat. The transparent, gelatinous, sarcodic
substance forms the entire mass of the body
and tentacles ; on the surface it is frequently
irregularly rounded or nodular, or exhibits
spiral or other raised lines (PI. 41. fig 23 6) j
and it contains numerous vacuoles within.
If a Hydra be crushed between glasses,
portions of the sarcode will be separated,
and assume a globular form, closely resem-
bling that of cells ; the vacuoles will also
become greatly distended, just as occurs in
the substance of the Infusoria ; and these
separated portions will often continue con-
tracting like an Amoeba. Two of them are
represented in PI. 41. fig. 29 ; in a, a rather
small vacuole is present, whilst in b this is
very large. Now in the latter instance the
globule, as regards structure, forms a true
cell, consisting of a closed sac, with liquid
contents. Physiologically speaking, how-
ever, it does not correspond to a cell, the
entire substance representing cell-contents
around which a cell-wall has never been
formed. A number of these vacuoles exist
naturally, diffused throughout the substance
of the body. The protoplasts of the inner
surface are ciliated, and solid particles are
ingested by them as in Amoeba. The inter-
mediate stratum, which is not organically
distinct, contains imbedded in it a number
of very minute green or otherwise coloured
granules ; these are of a rounded form, and
present a double outline, as if composed of
cells. In the uninjured Hydra they exist
in the intervacuolar substance, thus giving
the tissue an elegantly reticular appearance.
They appear to consist of chlorophyll ; they
are insoluble in potash ; they become
coloured purplish red-brown by iodine and
sulphuric acid, after treatment with potash ;
and the green-granules of Hydra vulgaris
are rendered bluish green by sulphuric
acid, in the same manner as the chlorophyll

HYDRA.

[ 398 ]'

HYDRA.

of leaves. The colour of Hydra has been
differently accounted for. Laurent states
that he succeeded in colouring them blue,
white, and red, by feeding them with in-
digo, chalk, and carmine, — whilst Hancock
has shown that the colouring is much
affected by exposure to light — those not
exposed to light, from living under stones,
&c., having the natural colour, whilst those
exposed to the light became bleached. It
is generally admitted, however, that the
colour depends upon or is modified by the
nature of the food ; but exact experiments
are wanting to decide the question. Towards
the inner surface of the body, the granules
are brownish or blackish.

Imbedded in the superficial portions of the
substance of the Hydra are certain curious
bodies, termed the stinging organs or nema-
tocysts (PI. 41. fig. 23 a). These are best
seen upon the tentacles ; they consist of
an oval, truncate, firm capsule (PI. 41.
fig. 22 6) of comparatively considerable
thickness, as indicated by its marked double
outline. Within the capsule is contained
a very long and slender filament, at the
base of which are four minute spines. In
the undisturbed state of the Hydra, the
filament with the spines is coiled up in the
capsule (fig. 22 a) ; but when the animal is
touched, pressed, or heated, the filament
with the spines flies out with extraordinary
rapidity, so that we have not been able to
determine exactly how the spines are ar-
ranged within the capsule. Most probably
the spines, while within the capsule, are
directed forwards and in close contact, and
then, in assuming their recurved position,
they are the means of projecting the filament
forwards. A capsule, containing an unex-
panded filament and spines enclosed within
a detached globule of sarcode, is represented
in fig. 22 d. When these capsules are heated
with a solution of nitrate of silver, a portion
of the silver is reduced to the metallic state.
This action is a property of formic acid ;
hence,when it is considered that these organs
closely resemble in structure those of the
Acalephse, which possess anurticating power
like stinging-nettles/ arising from the pre-
sence of formic acid, and that in Hydra
these filaments are driven into and wound
the prey, it may appear probable that they
secrete and contain formic acid. But, as
many other substances reduce salts of silver,
and as the sarcode, from which it is perhaps
impossible to separate these bodies, may
produce this effect, the point must be con-

sidered doubtful and requiring further in-
vestigation. In addition to these stinging
organs, we have found other very minute
capsules (fig. 22 c), containing a filament,
curved even when emitted, the nature of
which is obscure.

A third kind of organ is said to have been
met with also in the surface of the body,
consisting of ovate capsules or bodies, from
which a stout and short filament projects;
these appear to resemble the organs of ad-
hesion of the Acalephae.

The body and tentacles of Hydra are hol-
low. The prey, which consists of Entomos-
traca, small Annulata &c., when caught by
one or more of the tentacles extended for
the purpose, is slowly brought to the mouth,
and forced into the cavity of the body, in
which it is digested, certain portions being
taken up by the amoeboid bodies ; the un-
digested portions are evacuated through the
mouth. The posterior part of the body is
more or less dilated into a flattened disk,
which, by its suctorial power, enables the
animal to attach itself to various bodies ;
Hancock has seen excrementitious matter
passing through the body at this part. The
cavities of the tentacles sometimes exhibit
a kind of circulation ; and those of both the
tentacles and the body are lined with cilia.

The extraordinary power which Hydra
possesses of reproducing lost parts is truly
wonderful. Thus, if the body be cut into
two or more, even into forty parts, each
portion continues to live, and develops a
perfect new animal. If the section be made
lengthwise, so as to divide the body all but
the end, the two portions become resoldered
and form a perfect being ; if the pieces be
kept asunder, each becomes a Hydra, the
two possessing but one posterior end ; if the
section be made from the tail towards the
head, the two bodies will be perfected and
remain attached to the one head. If a
tentacle be cut off, a new animal is formed
from it. When one end of the body of a
Hydra is introduced into the body of
another, the two unite and form one. The
head cut off one may be engrafted upon
the body of another which wants one. And
when the body is turned inside out, the
outer surface, which has thus become the
inner, will perform the ordinary digestive
functions, and the animal will continue to live.

The ordinary mode of reproduction of
Hydra is by gemmation : a minute swelling
forms upon some part of the surface of the
body j this enlarges, and gradually assumes

HYDRA.

[ 399 ]

HYDRACHNA.

the form of the parent, while remaining
attached to it. Sometimes several of these
are formed upon a single individual at the
same time, and so, remaining adherent,
thev give the animal a branched appearance
(PL 41. fig. 21).

At certain seasons of the year, as at the
end of summer or in the autumn, reproduc-
tion takes place by the formation of sperma-
tozoa and ova. The spermatozoa are formed
within spermatic capsules. These arise as
minute conical tubercles a little beneath the
base of the tentacles, one on each side
(PI. 41. fig. 24 a) ; and the spermatozoa are
liberated from them by bursting. The sper-
matozoa resemble those of the Mammalia,
except that the tails are undulate. The ova
are furnished with a thick coat, and are
formed in the substance of the lower part
of the body (fig. 24 6). They subsequently
separate from the body, and appear to be
capable of spontaneous motion; but whether
from the presence of cilia or not, is unde-
cided. The ovisac then becomes ruptured,
and the new animal escapes (fig. 25).

Hydrce are very common. The best me-
thod of procuring them is to collect a number
of water-plants from any clear pool or slow
stream, and bring them home in an india-
rubber bag (sponge-bag). On placing the
Elants subsequently in a glass jar (con-
3cti oner's jar) containing water, they will
be found at the end of some hours with the
tentacles fully extended in search of prey,
when they are easily recognized. They
usually adhere to the sides of the glass, or
to the stems or undersides of the leaves of
the plants ; but sometimes they are seen
suspended from the surface of the water by
the sucker, which is protruded just above
it so as to become partly dry. A number
of small Entomostraca should be added to
the water, as the Hydros are very voracious.
Some of the species of Hydra are occa-
sionally covered with minute parasitic Infu-
soria, viz, K&'ona polyporum (PI. 50. fig. 13),
which is found upon H. mdqaris and fusca,
and Trichodina pediculus (PI. 31. fig. 16),
which occurs upon H. wdgaris and viridis.
It is an interesting sight to see these running
up and down the tentacles and surface of the
body of the polypes, when we recollect that
their surface is covered with the stinging
organs, These lice are not, however, found
in any numbers upon perfectly healthy
polypes, impurity of the water and an un-
healthy state being generally denoted by
their presence.

Parker recommends osmic acid in the
examination of the minute structure of
Hydra-, and hardening in bichromate of
ammonia for sections.

BIBL. Leeuwenhoeck, Phil Tr. 1703,
xxiii. ; Trembley, Polyp, d'eau douce ; Lau-
rent, Rech. s. VHydre ; Corda, Ann. Sc.
Nat. 2 ser. viii. ; Schaefler, D. Armpolyp. ;
Erdl, Mutter's Archiv, 1841 ; Ecker, Sieb.
and Koll. Zeitsch. i. ; Johnston, Br. Zooph. ;
Thomson, Todays Cycl. An. and Phys. iv.
17 ; Hancock, Ann. N. H. 1850, v. 281 ;
Allnian, M-icr. Journ. 1854 ; Hincks, Br.
Zooph. 309; Kleinenberg, Hydra, 1872;
Allman, Qu. M. Jn. 1874, xiv. 1; T. Parker,
Pr. Hoy. Soc. 1880, 61.

HYDRACH'NA, MiiU. — A genus of
Acarina, family Hydrachnea.

Char. Palpi tolerably long, third joint
longest, the fourth and fifth terminated each
by a claw ; mandibles ensif orin ; rostrum
long, scarcely shorter than the palpi ; body
rounded ; eyes distant ; vulva concealed by
a plate or shield.

When young, these little water-spiders
have three legs only, and in this state have
formed another genus, Achlysia. Several
species :

H. crttenta, Mull. = H. globula, Herm.
(PI. 6. fig. 29). Body subovate ; two pairs
of eyes at a moderate distance apart, reni-
form, dark red ; skin covered with minute
puncta.

The rostrum is broad and curved at the
base (fig. 29 c, the lower part directed to the
left), cleft above, so as to form a kind of
channelled sheath, containing the anterior
narrower portions of the two mandibles (b).
The palpi (c, upper organ) are inserted upon
the sides of the base of the rostrum and
curved downwards ; the first joint is very
broad, the second much curved, the third
long, and flattened on one side and rounded
on the other ; the fourth joint is short, and
terminated by a short and thick claw ; the
fifth also forms a claw, but the two claws do
not form a chela, their curves being parallel.
Of the legs (fig. 29 a), the three posterior
pairs are ciliated for swimming, and the
posterior are much longer than the anterior ;
the coxae are flattened and form two groups
on each side ; between the two posterior
coxae is the orifice of the reproductive
organs ; the tarsi all have two claws, and
are obliquely truncated and concave at the
end (fig. 29 e).

The eggs are reddish-brown and deposited
upon the stems of water-plants ; the nymphse

HYDEACHNEA.

[ 400 ]

HYDROCYTIUM.

are found attached to aquatic insects (fig.
29 y), as Nepa,Dytiscus, &c.

H. geographica. Body spherical, black,
with spots and yellow points ; palpi red,
acute ; legs shorter than the body, black,
but red at the ends.

H. concharum. Inhabits the pallial cavity
of the Naiades.

BIBL. Duges, An. Sc. Nat. 2 se*r. i. ; Ger-
vais, Walckenaer1 s Arachn. iii. ; Koch,
Deutschl. Crustac. ; Murray, EC. Ent. 157.

HYDRACH'NEA (Water-spiders).— A
family of Acarina.

Palpi with the last joint unguiculate or
spinous ; two or four distinct ocelli ; coxae
broad, legs generally ciliated, natatory, the
posterior longest, tarsi with two claws.

The characters of the genera must be
sought under the individual heads. See
ARRENURUS, ATAX, DIPLODONTUS, EYLAIS,
HYDRACHNA, and LIMNOCHARES.

HYDRACTINTA, V. Bened.— A genus
of Hydroid Polypi, of the family Hydrac-
tiniidae.

Char. Polypidom incrusting ; polypes
claviform, tentacles in a single whorl at the
base of a conical proboscis.

H. echinata. Polypidom rough with ser-
rated spines, whitish fleecy. On univalve
shells tenanted by the hermit crab.

BIBL. Hincks, Brit. Zooph. p. 19.

HYDRALLMAN'IA, Hincks.— A genus
of Hydroid Zoophytes, f am. Sertulariidae.

H. falcata—Plumulariafalc. Johnst.

BIBL. Hincks, Brit. Zooph. p. 273.

HYDRAN'THEA, Hincks— A genus of
Hydroid Polypi, fam. Atractylidae.

H. margaritacea, white ; on Flustra
foliacea.

BIBL. Hincks, Ann. N. H. 1863, xi. 45 j
and Br. Zooph. 99.

HYDRIA'NUM, Rab.— A genus of Pal-
mellaceous Algae.

Char. Cells resembling those of Chara-
cium, but open at the ends ; endochrome
contracted, ultimately becoming resolved
into 2-4-8 zoogonidia. H. ovale (PI. 62.
fig. 5).

12 species : freshwater ; adherent to other
Algae.

BIBL. Rabenhorst, Fl. Alq. iii. p. 87.

H Y'DRIAS, Ehr.— A genus of Rotatoria,
of the family Philodinaea.

Char. Eyes absent; neither proboscis
present, nor horn-like processes on the foot ;
rotatory organs two, placed at the ends of
two anterior processes of the body.

H. cornigera (PI. 43. fig. 39). Body ovate,

hyaline ; foot narrowed into the form of a
slightly forked tail ; freshwater ; length
1-190".

Probably a young and imperfectly exa-
mined Philodina. Found in Egypt.

BIBL. Ehrenberg, Infus. p. 483.

HY'DRID^E.— A family of Zoophytes,
order Hydroida.

It contains the single genus Hydra.

HYDROCHARIDA'CE^E.— A familyof
Monocotyledonous Flowering Plants grow-
ing in water, interesting to the microscopist,
as affording very favourable opportunities of
viewing the circulation or rotation of the
cell-contents. The leaves of Vallisneria
spiralis, an Italian plant, which is readily
grown in jars of water indoors, are very fre-
quently used for this purpose ; the leaves
and sepals ofAnacharisAlsinastnim, a North
American plant, now naturalized in streams
in many parts of Britain, also show the cir-
culation well. The extremities of the roots
of Hydrocharis morsits-rance, a plant com-
mon, floating on the surface, in broad per-
manent ditches, are likewise adapted for the
purpose. The circulation consists of the
flowing movement of a layer of colourless
protoplasm over the inner surface of the
walls of the cells. Where, as in the leaves
of Vallisneria and Anacharis, the cells con-
tain green globules of chlorophyll, these
mostly adhere to the circulating mass, and
are carried round with it. The phenomenon
may be observed in uninjured young leaves
simply immersed in water by focusing care-
fully ; but in Vallisneria it is seen more
clearly in slices taken carefully parallel to
the surface of the leaf. The circulation
lasts a long time in these separate frag-
ments if they are kept wet. Sometimes it
is arrested by the preparation j in such cases
the application of a gentle heat often causes
it to recommence. It may be observed with
a power of 200 diameters ; but a higher is
requisite for minute investigation. (See
ROTATION.)

HYDROCHORE CITES, Koch, = Hyd-
rachna, pt.

HYDROCO'LEUM, Kiitz.— A genus of
Oscillatoriaceee (Confervoid Algae), corre-
sponding to aquatic species of * Chthono-
blastus. H. helveticum (PI. 52. fig. 6).

11 European species.

BIBL. Kiitzing, Phyc. Gen. 196 ; Raben-
horst, Fl Alg. ii. p. 149.

HYDROCY'TIUM, Al. Braun.— A genus
of unicellular Algse, separated from that
author's Characium on account of the whole

HYDRODICTYON.

[ 401 ]

HYDRODICTYON.

Fig. 338.

contents becoming at once broken up into
active gonidia, not by successive subdivi-
sions (PI. 5. tig. 1). Green. Found upon
stones or filamentous Confervas in fresh
water, and consisting of elliptical sacs or
cells, acuminate above and below, about
1-500" long and 1-1200" thick. _ 2 species.

BIBL. Al. Braun, ALy. Unicell., Leips.
1855, 24.

HYDRODIC'TYON, Roth.— A genus of
Siphouaceae (Confervoid Algae), containing
one species, H. utriculatum, found in fresh-
water pools in the midland and southern
counties of England. The frond or cceno-
bium consists of a green open network of
filaments attaining a length of 4 to (3" when
full-grown (iig. 338), composed of a vast
number of cylindrical tubes
(cells) with rounded ends,
adherent together at their
extremities, the points of
junction corresponding to the
knots or intersections of the
network. The individual
cells attain a length of 4'" or
more. The organization of
this plant and its develop-
ment are exceedingly curious;
and it has lately been the
subject of very careful inves-
tigation by Al. Braun and
others. The cells forming
the links of the net have a
remarkably thick cellulose
coat when full-grown, which
exhibits several layers, espe-
cially when treated with sul-
phuric acid (PI. 47. fig. 24 J).
Weak sulphuric acid does not
affect the outer cuticular A complete frond
layer, while it swells the
inner layers, and throws them size.
into waves, especially the in-
nermost ; the subsequent addition of iodine
colours the inner layers blue, but not the
cuticle. Strong sulphuric acid acts diffe-
rently : it detaches the cuticle at many
points, while the inner layers contract, so
that the cuticle appears blown up in vesicles ;
the inner layers gradually soften and dis-
solve. These last changes are similar to
what takes place at the dissolution of the
cell when the contents escape ; and Cohn
states that the membranes give the bluish
reaction wdth iodine alone when thus par-
tially decomposed by natural causes.

Immediately lining the wall is a mucila-
ginous layer (PI. 47. tig. 24^?), which Braun

Hydrodictyon

utricuiatum.

has shown to consist of several lamellae : —
1. An extremely thin, finely punctate layer,
coagulated and detached from the cell-wall
by the action of acids ; this is the primor-
dial utricle of the cell. 2. The outer muci-
laginous layer, thicker than the primordial
utricle, but thinner than the next or third
layer. When separated from the first layer,
the outer surface appears rough and wavy ;
and it is connected with the third layer by
mucilaginous cords ; it contains indistinctly
defined colourless granules. 3. The inner
mucilaginous layer, the thickest of the three,
is rough on the outside and waved on the
inside from the projection of granules im-
bedded in it ; this is the only green layer,
appearing of a homogeneous green colour
(like the spiral bands of Spirogyrd) when
the cells are in their prime, besides which
it contains innumerable green granules,
sometimes in rows, more frequently uni-
formly scattered. This layer likewise con-
tains starch-corpuscles, such as occur com-
monly in the green substance of the Confer-
voids, causing the cell-contents to exhibit a
vast number of brilliant points. In imperfect
cells the green layer sometimes appears in

Satches, not completely investing the sur-
ice of the outer mucilaginous layer ; this
is also common in young cells. The fluid
in the cavity of the cell is clear and watery.
The reproduction of the fronds of Hydro-
dictyon is effected by the conversion of the
contents of the individual cells into com-
plete new sets like the parent, which lets
them free by dissolution. The following is
a brief history of this remarkable process.
The first stage is the solution of the starch-
grains; the green layer becomes more
opaque ; lighter spots appear on the inner
part of the mucilaginous layer, excavated
in its substance and surrounded by the
chlorophyll-globules, which separate from
each other, forming dark boundary lines
round the light spots. The bright-green
then gives place to a browner tinge. The
light spots already observed (the centres of
the nascent gonidia), exerting an attraction
as it were on the chlorophyll-globules, be-
come severally enveloped in a layer of them,
and then separate from each other, so as to
appear like dark spots with an intervening
reticulation of bright lines. The dark spots
(gonidia) are now polygonal, mostly six-
sided, about the 1-2500" in diameter. The
parent-ceh1 membrane next begins to soften
and swell up ; the gonidia, thus acquiring
more space, become rounded, and soon pre-

2D

HYDRODICTYON.

[ 402 ]

HYDROIDA.

sent a slight tremulous oscillatory move-
ment. The cuticle of the parent cell then
cracks, allowing the inner softened layers
to swell out; the gonidia commence an
active trembling and jerking motion, not,
however, moving far from one spot ; after a
time they again come to rest, and become
united at certain points of their circum-
ference ; the green granules become fused
into a homogeneous mass, and the rudi-
ment of the first starch-granule soon ap-
pears, while the gonidia grow out into a
tubular form, acquire a cellulose membrane,
and collectively form a new net, which be-
comes free by the total solution of the pa-
rent cell. These gonidia appear to possess
four short cilia ; their motion lasts about
half an hour ; from 7000 to 20,000 occur in
one cell; and they are distinguished by
Braun as macrogonidia. Other gonidia of
smaller size and longer shape, which he
calls microaonidia, are furnished with four
long cilia and a red parietal spot. These
have a different history. From 30,000 to
100,000 appear in the parent cell, their de-
velopment presenting the same characters
as that of the macrogonidia up to the time
when the motion begins. Then the micro-
gonidia, unlike the net-forming macrogoni-
dia, leave their parietal positions with a
whirling motion, and move through the
entire cavity of the parent cell, until at
length the membrane of the latter bulges
out in one or more places and bursts, and
the microgonidia leave the cavity in a
swarrn. According to Cohn, they are at
first enclosed in a thin mucilaginous pellicle
protruded before them, like the swarming
spores of PEDIASTRUM. However, they
escape, become free, and swim about for a
long time, and are supposed to conjugate.
At length they come to rest, acquire an
outer coat, sink to the bottom, and remain
there heaped in green masses, like cells of
PROTOCOCCUS, for a long period, forming
resting-spores.

The rapidity of the growth of the Hydro-
dictyon-net by the above process is wonder-
ful ; the component cells of the net increase,
under favourable circumstances, to 600 times
their original length in a few weeks. In
cultivated specimens, the whole history,
from the origin of a net to the production
of a new one, passes over in three or four
weeks. The original size of the cells is
about 1-2500"; in the fully developed con-
dition they are about 1 to 4" long.

BIBL. Vaucher, Conferves, 82, pi. 9;

Areschoug, Linncea, xvi. 127, pi. 5 (1842) ;
Hassall, AlgcB, 225, pi. 58 ; Braun, Verjilng.
(Ray Soc. 1853); Ala. UniceU. Sp. Nov.
1855, 55 j Cohn, Nova Acta, xxiii. 207, pi.
19; Pringsheim, Serl. Ber. 1860; Qu. M.
Jn. 1862, 54, 104.

HYDROGAS'TRUM, Desv. = BOTRY-
DIUM:.

HYDROI'DA.— The order of Hydroid
Polypes (Zoophytes).

The members of this Order usually con-
sist of aggregate hydriform individuals
contained in cells or cups, springing from a
filiform branched polypidom; propagation
gemmiparous and oviparous. Many new
names have been used for the component
structures, which may well be mentioned
here ; but we prefer the old ones. One of
the forms of non-sexual reproduction is the
zooid. Zooids differ from organs in that
the zooid is an individual organism, which
may or may not be capable of individual
existence. A community of zooids in union
with one another constitutes the hydrosome.
Zooids are of two kinds : in one, destined
for the nutrition of the community, the as-
semblage is called the trophosome ; the other
gives origin to the generative elements —
ova and spermatozoa ; and the entire asso-
ciation ot these generative zooids is the
gonosome. The trophosome is composed of
the hydranth and the hydrophyton. The
hydranth or polypite contains the digestive
sac; the hydrophyton or ccenosarc is the
common basis by which the general com-
munity is kept together. The hydrorhiza
is the adherent base. The ultimate zooid,
which generates either the ova or the
spermatozoa, is the gonophore. The sporo-
sac is the gonophore without the umbrella.
The gonozoid is the sexual zooid, whether
fixed or detached and fitted for locomotive
life; this is also known as a medusiform
gonophore, or plnnoblast. The gonangium,
or gonotheca, is an external receptacle in
which the gonophore is formed. (Pascoe.)
See ZOOPHYTES.

Hincks divides the Order into 3 sub-
orders : —

1. Athecata (Tubularina, Johnst), in
which true thecae are absent. Fam. :

Clavidffi.

Hy dractiniidse .

Podocorynidse.

Laridee.

Corynidae.

StauridiidsD.

Clavatellidaj.

Myriothelidae.

Eudendriidae.

Atractylidae.

Tubulariidoe.

Pennariidse.

HYDROMETRID.E. [ 403 ]

HYDRURUS.

2. Tliecaplwra (Sertularina, Johnst.), in
which the Hydroida are furnished with
thecae. Faui. :

Campanulariidae. Coppiniidae.

Campanulinidse. Haleciidae.

Leptoscyphidae. Sertulariidae.

Lafoeidae. Plumulariidae.
Trichydridae.

3. Gymnochroa (Hydrina, Johnst.). Poly-
pidom absent ; locomotive. Fam. 1. Hy-
dridaa.

The polypidoms of the Hydroid Polypi
form interesting microscopic objects. They
are very common among sea-weeds, on
shells, rocks, &c., the forms being often
elegantly branched and feathery (PI. 41.
figs. 4, 11, 15, 16) ; and the species can be
identified from the polypidoms. They may
be mounted, after being well-washed in
distilled or rain-water, in balsam or gly-
cerine. The animals are very irritable and
contractile, and can only be observed after
the removal of the bodies to which they are
attached to an aquarium or jar containing
sea- water.

BIBL. Johnston, Br. Zooph. 5 ; Gosse,
Mar. Zool. 1, 18; Allman, Ann. N. H. 1863,
xi. 1 ; Hincks, Br. Zooph. i ; and Ann. N. H.
1877, xix. 148, 1878, i. 239 ; 1880, vi. 277
(Barents Sea); Mereschowski, ibid. 1878,
ii. 251 ; Korotneff, ibid. 1878, ii. 351 ;
Thompson, ib. 1879, iii. 97 ; Pascoe, Zool.
Class. 1880.

HYDROMET'RID^].— A family of He-
mipterous (Heteropterous) Insects, the spe-
cies of which are found skimming the sur-
face of pools or rivers. The under parts of
the body and legs are covered with fine
hairs, which prevent them from becoming
wetted. The eggs of Hydrometra are ellip-
tical and elegantly sculptured.

BIBL. Westwood, Introduction, ii. 467.

HYDROMORI'NA, Ehr.— A family of
Infusoria.

The two genera of which it consists, Po-
lytoma and Spondylomorum, appear to be
Monads, or species of Algae, undergoing
division. See these genera.

BIBL. Ehrenb. Ber. d. Berl. Akad. 1848.

HYDROPH'ILTJS, Geoff See HYDROUS.

HYDROPH'ORA, Tode.— A genus of
Mucorini (Phycomycetous Fungi). Moulds
growing on the dung of animals, distin-
guishedby the indurated persistent peridiole
and the conglobated spores. Two species
are described as British.

H. stercorea, Tode. Fleecy ; filaments
simple, very long, fugacious, white ; peri-
dioles spherical, yellow, subsequently black.
Common on dung after much rain.

If. murina, Fr. Filaments scattered,
short, simple, persistent, white ; peridioles
yellow, subsequently opaque. On rats' dung.
(Mucor fulvus, Sowerby, pl/400. fig. 4.)

BIBL. Berkeley, Hook. Br. Fl. ii. pt. 2.
331 ; Fries, Syst. Mycol. iii. 314, Sum. Veg.
87.

H YDROSE'RA, Wall.— A genus of Dia-
tomaceae.

Char. Frustules quadrate, areolar, united
into a filament, with internal septa ; hoop
smooth, compressed or triangular in front
view, areolar, the constricted angles with a
small appendage on one side. Marine.

H. compressa. Valves oblong. East Indies.

H. triquetra (PI. 51. fig. 40). Valves
triangular. East Indies.

H. tricoronata. New Zealand.

BIBL. Wallich, Qu. M. J. 1858, vi. 251 ;
Stolterforth, Jn. Mic. Soc. 1881, 424.

HYDRO'US, Linn.— A genus of Coleo-
pterous Insects, of the family Hydrophilidae.

H. piceus is one of the largest aquatic
British beetles. We have selected the head
to illustrate the structure and arrangement
of the trophi, &c. in the Coleoptera (see
INSECTS). The perfect insect is about 1|"
in length. The full-grown larva is about 3"
long ; it has no lateral branchiae, but two
filiform branchial appendages at the end of
the body.

BIBL. Westwood, Introduc. ; Dumeril,
Consid. gen. s. 1. Insectes ; Stephens, Br.
Beetles.

HYDRU'RUS, Ag.— A genus of Pal-
me! laceae (Confer void Algae), which seems
to form a link between these and the UL-
VACE^;. The frond consists of a branched,
feathery, very gelatinous expansion, the
branches set with minute processes or ra-
melli (PI. 7. fig. 8«) ; in the gelatinous
substance are imbedded minute cells with
homogeneous green contents, most closely
set in the ramelli, more scattered in the
older part of the frond (PI. 7. fig. 8b). H.
Ducluzelii, Ag., grows to a length of from
1 to 6", and from 2 to 4'" in diameter,
attached to stones in mountain-brooks and
rivers; the recent frond is of brownish
olive in mass, green when dried. When
fresh it has a very offensive smell. Repro-
duction by active gonidia.

BIBL. Harvey, Br. Ala. (1 ed.) 180-
Hassali, Alg. 302, pi. 77. fig. 3 ; Kutzin^,
2 D2

HYGROCROCIS.

[ 404 ]

HYMENOMYCETES.

Tab. Phyc. pi. 34. fig. 3 ; Rabenhorst, FL
Alg. iii. 49.

HYGROCRO'CIS, Ag.— A supposed
genus of filamentous Confervas ; apparently-
consisting of the flocculent mycelium of
Fungi. H. arsenica occurs in solutions of
arsenious acid.

BIBL. Kutzing, Sp. Alg. 148; Raben-
horst, FL Alg. ii. 8 (tig.) ; Marchand, Compt.
rend. 1878.

HYME'NIUM.— The term applied to
the layer of cellular tissue upon which are
seated the basidia of the higher FUNGI.
The name is also applied to the fructifying
stratum in such Ascophorous fungi as Hel-
vella, Morchelki, Peziza, &c.

HYMENO'MONAS, Stein.— A genus of
Flagellate Infusoria.

Char. Free, with a crenate, flexible cara-
pace j flagella two ; no eye-spot ; lateral
yellow-brown pigment bands present.

H. roseola; length 1-850'': freshwater.
(Kent, Inf. 407.)

HYMENOMYCETES.— A tribe of Ba-
sidiomycetous Fungi, characterized by the
peculiar mode of arrangement of the spores,
which are borne in groups of four on the
exposed surface of a more or less membra-
nous or sometimes gelatinous layer called
the hymenium. The fruit, called the re-
ceptacle, varies extremely in form. In
most of the Tremellini it is an irregular
jelly-like or waxy expansion, borne how-
ever on a roundish support in Tremella; in
the Clavati it forms a club-shaped, mostly
branched, fleshy or leathery stalk-like body
(called the hymenophore}^ which is clothed
at its ends by the sporiferous membrane or
hymenium, forming a smooth layer. In
the Auriculati and Hydnei the receptacle
is either an expanded, irregular, crust-like,
membranous or leathery mass, or has the
form of a club, a funnel, or of a hat or cap,
the sporiferous membrane clothing either
the upper or under surface as a warty,
spiny, or comb-like stratum.

In Polyporei and Agaricini the receptacle
is a discoid (often laminated), bell-shaped
or dish-formed, fleshy body, more or less
coloured and tuberculated on the upper side,
frequently borne on a columnar stalk in-
serted on the under side, while the sporife-
rous layer, or hymenial structure, presents
itself as a conspicuous layer on the under
side, consisting of a number of paper-like
lamellae, or vertical tubes, prickles, or pits,
closely packed, on the lateral surfaces of
which are borne the spores; in many

cases, however, the hymenium is perfectly
even in the column. The younger stages
of development of some Hymenomycetes
do not exhibit all these characters, since
the receptacle is at first enclosed in a sac-
like body arising from the mycelium, so
that the external appearance is similar to
that of one of the Gasteromycetes (as in
very young mushrooms) ; this sac finally
bursts, to allow of the expansion of the
receptacle.

The cellular structure of this family is
simple, in spite of the varied outward
forms ; the whole mass, from the filamentous
mycelium up to the sporiferous membrane
or hymenium, is made up of interwoven
branched cellular filaments or hyphae, of
great tenuity. In the Tremellini these fila-
ments are imbedded or dissolved into an
amorphous waxy or gelatinous substance ;
in other cases they form a dry corky struc-
ture ; but the consistence is generally fleshy.
In a few cases among the Agaricini and
Polyporei, vesicular or elongated branched
hyphas of considerable size are met with,
containing a milky juice (in the gills of
Ag. deliciosus, &c.). The spores are short
terminal branches of roundish or elongated
cells, called basidia, clothing the free surface
of the hymenial structure (see BASIDIO.-
SPORES). They may be seen in thin cross
sections cutting the laminae of the Agarics
or the tubes of the Polyporei at right
angles, requiring a high power for their
observation. Four spores are formed on
each basidium, from which they fall off
when mature. The Agarics exhibit on the
hymenium, among the basidia, peculiar pro-
jecting vesicles filled with opaque fluid (pol-
linaria, Corda ; cystidia, Leveill6 ; utricles,
Berkeley), which some have called anthers,
but which appear to be paraphyses — that
is, undeveloped or abortive (bare) basidia.
The spores are mostly exceedingly minute,
of various forms and colours, and consisting
of simple cellules. Tulasne has recently
shown that the Tremellini produce sperma-
tia, as well as basidiospores j in Tremella,
and other genera, they arise from distinct
branches of the hymenial filaments ; in
Dacrymyces they are produced in germina-
tion from some of the detached basidio-
spores lying upon the mycelium (see TRE-
MELLINI).

The structure of these Fungi must be
investigated in all stages of development,
since very great changes of size and
form take place at different epochs, simply

HYMENOPHYLLE^E. [ 405 ] HYMENOPHYLLEJE.

from expansion or solution of the cellular
textures.

Synopsis of the Families.

AGARICINI. Eeceptacle like a round or
flat cap, oftenborne on a stalk. Hyme-
nium forming vertical plates or folds on the
under surface.

POLYPOREI. Receptacle like a round or
flat cap, disk, cup, or funnel, sometimes
stalked, with a porous (formed of tubes) or
reticulated hymenium on the under side.

HYDNEI. Receptacle like a round or
flat cap, cup, or funnel, sometimes stalked,
with the hymenium on the under side ex-
hibiting awl-shaped processes or tubercles.
AURIC UL ARES i. Receptacle tubular,
cup- or funnel-shaped, with the smooth or
papillose hymenium on the under surface.

CLAVATI. Receptacles club - shaped,
simple or branched like a shrub, with the
hymenium covering the tips and sides oi
them.

TREMELLINT. Receptacle vague, or cup-
shaped, often gelatinous at first, hardening
by drying up. Hymenium confounded
with the structure of the receptacle, on the
upper, under, or both surfaces j ba,sk"
terminating the branches of hyinenial fila-
ments, accompanied sometimes by branches
bearing sperm atia. The detached spores
often lie imbedded in the gelatinous surface
of the hymenium, and sometimes produce
spermatia there. The above characters refer
to the more typical species, as resupinate
forms or an expanded hymenophore occur
in each of the divisions.

BIBL. Berkeley, Lindley's Veg. Kingdom •
Hooker's Br. Flora, vol. ii. pt. 2 ; Ann. N. H.
i. 81, and ix. 1; Leveille, Ann. Sc. N. 2 se>.
viii. 321 ; Fries, Sum. Veg. 267 ; Tulasne,
Ann. Sc. N. 3 ser. xix. 193.

HYMENOPHYL'LE^E.— A family of
Polypodiaceous Ferns, distinguished by the
delicacy of the structure of their leaves and
the composition of the sori or fruits. The
leaves are of the utmost simplicity of or-
ganization, consisting ordinarily of a single
layer of cellular tissue, traversed by scala-
riform tubes constituting the veins. There
is no distinction of epidermis and paren-
chyma, nor are there stomata.

Genera.

Trichomanes. Sporanges sessile around
the base of an exserted filiform column,
formed by the prolongation of a vein be-
yond the margin of the leaf, surrounded by

a cup-shaped indusium continuous with the
leaf (fig. 339).

Hymenophyllum. Sporanges sessile up
to the summit of a similarly formed column
projecting from the margin of the leaf, sub-
elevated, but not exserted beyond the indu-
sium, which is two-valved (fig. 340).

Fig. 339.

Fig. 340.

Trichomanes humile. Hymenophyllum bivalve

Fig. 339. Fragment of a leaf, with sori.
Fig. 340. Ditto.

Magnified 10 diameters.

Loxosoma. Sporanges stalked, inserted
up to the summit of a subelevated exserted
column arising in a similar way within the
margin of the leaf, surrounded by an indu-
sium, somewhat within the margins of the

Fig. 341.

Fig. 342.

Fig. 343.

Hymenophyllum ciliatum.

Fig. 341. Fragment of a leaf. Magn. 10 diams,
Fig. 342. Sorus with one valve removed Mang. 40

diains.
Fig. 343. Sorus. Magn. 20 diams.

HYMENOPHYLLUM. [ 406 ] HYPHOMYCETES.

fissures between the teeth of the leaf, with
a truncated entire mouth ; annulus incom-
plete.

HYMENOPHYL'LUM, Smith.-Filmy
Ferns. The typical genus of Hymenophyl-
laceous Ferns, remarkable for their delicate
structure and often almost moss-like habit.
Two dwarf species are natives of Britain,
H. tuiibridgense and //. Wilsoni. Numerous
tropical species (Hooker, Syn. 56).

HYMENOP'TERA.— An order of IN-
SECTS, containing the Bees, &c.

HYPERAM'MINA, Brady.— A tubular
and sandy Foraminifer, irregular in exten-
sion and growth. (Brady, Ann. N. H. 1878,
i. 433 ; Mic. Jn. n. s. xix. 13.)

HYPER'ICUM, Linn. — Hinds points
out in the leaves of If. Androscemum, the
common Tutsan, and calycinum, certain
dots containing active motile bodies (M.
M. Jn. xix. 233).

HYPEROMYX'A, Corda. See CHEIBO-

SPOBA.

HYPH'EOTHRIX, Kiitz.— A genus of
OSCILLATORIACE^E (Confervoid Algse).

Char. Fil. simple, jointed, coloured, more
or less distinctly sheathed, tranquil ; fasci-
culate or densely united into a more or less
membranous non-radiate stratum (PI. 62.
fig. 8).

68 European species. In springs, coating
water-plants in pools ; on rocks, &c.

BIBL. Rabenhorst, Fl Alg. ii. 75.

HYPHOMYCETES. — A section of
Fungi composed of microscopic plants,
growing as moulds over dead or living
organic substances. These are now con-
sidered to be conidiiferous conditions of
Ascomycetous Fungi ; but as they are in-
teresting and often very beautiful micro-
scopic objects, the original account is re-
tained here. The vegetative structure or
mycelium creeps over or among the struc-
tures infested as a collection of delicate,
simple or branched, continuous or septate
filamentous cells (flocci), and produces the
spores either on lateral pedicels (from which
they soon fall off, becoming intermingled
with the mycelium), or in heads at the
swollen or ramified extremities of usually
erect filaments (figs. 344, 345, 346, and 347).
These filamentous pedicels in most cases
exhibit a contraction just below the point
of origin of the spore, giving them the
same appearance as the pedicels of basidio-
spores. The spores are round (PI. 26. fig.
15), oval (fig. 347 and PL 26. figs. 5, 6),
spindle-shaped (FUSISPOBIUM), spiral (HE-

Fig. 344.

Fig. 345.

Fig. 344. Cephalothecium rosetun. Magn. 200 diams.
Fig. 345. Verticillium nutans. Magn. 200 diams.

LICOSPOBITJM), and isolated or connected
(fig. 346) in beaded lines (PENICILLIUM,
ASPEBGILLUS), or grouped in a stellate

Fig. 346.

Stysanus Caput-Medusse.
Magnified 200 diameters.

form. In the Isariacei and Stilbacei the
erect pedicels are composed of a number of
conjoined filaments ; in the other families
the pedicels are simple filaments. Some
authors include among these plants the
Mucorini (PHYCOMYCETES), regarding the
vesicular envelope of the spores there as a
mere veil, not a true cell producing the
spores in its interior. This family is of
especial interest from containing so many
moulds and mildews, and various parasi-
tical Fungi to which the diseases of plants,
and in some cases of animals, have been
attributed. Further particulars respecting

HYPHOMYCETES.

[ 407 ]

HYPNOIDE^E.

these will be found under the Families, also
PAEASITIC FUNGI.

Fig. 347.

Fig. 348.

Clonostachys Araucaria.
Fig. 347. Magn, 200 diams.
Fig. 348. A fertile branch. Magn. 400 diams.

Fig. 349.

Fig. 350.

Ceratocladium microspermum.
Fig. 349. Magnified 200 diams.
Fig. 350. Spores, magnified 400 diams.

Synopsis of the Families.

Is ABIACEI. Receptacle clavately branched,
or assuming Hymenomycetous forms, com-
posed of filaments closely attached in their
whole length; spores simple, attached to
simple pedicels arising in all parts (fig. 349).

STILBACEI. Receptacle wart-like or
elevate above, stalked below, composed of

filaments closely packed, coherent, termi-
nating singly in free subgelatinous spores.

DEMATIEI. Mycelium filamentous, spores
compound or simple, arising from the apices
of erect, solid, corticate, subopaque fila-
ments (fig. 346).

MUCEDINES. Mycelium filamentous,
spores solitary, or crowded on articulated
or branched tubular and pellucid filaments
(figs. 344, 345), soon separating and min-
gling with the mycelium, or adherent in
chained rows.

SEPEDONZEI. Mycelium filamentous,
spores usually found heaped together resting
on the mycelium, and apparently springing
out of it directly. The spores are the
principal element in this Order, which ap-
proaches Coniomycetes.

HYP'NEA, Lamouroux. — A genus of
Rhodymeniaceas (Florideous Algae), the
only British species of which, H.purpuras-
cens, is a common purplish pink feathered or
shrubby sea- weed, the lobes being cylindri-
cal, filiform, and cartilaginous, growing from
2" to 6" in height, with the filaments about
1'" in diam. On stones, rocks &c. between
tide-marks. The fructification consists of
coccidia, tubercles immersed in the ramuli,
each containing a mass of small spores ; and
tetraspores, immersed in the lesser branches,
of separate plants.

BIBL. Harvey, Mar. Alg. 130, pi. 16 D;
Phyc. Brit. pi. 116 ; Eng. Bot. pi. 1243.

HYPNOI'DE^E.— A family of Pleuro-
carpous Mosses of large extent. Leaves
with the cells prosenchymatous, dense or
lax, smooth or papillose. Alar cells at the
bases of the leaves diverse : 1 , square, flattish
or yentricosely impressed, pellucid or yel-
lowish, or fuscescent; 2, few, vesicular,
placed at the very base, of a delicate yellow
or hyaline ; 3, obsolete, scarcely any, placed
at the very base, fugacious, hyaline, vesi-
cular ; 4, many, square, in papillose leaves,
but mostly not very conspicuous. Leaves
0-5-nerved. Nerves binate, diverse : 1,
divergent from the base, distinct, very cal-
lous at the back of the leaf and prominent
in the form of a spine from the dorsal sur-
face ; 2, flattened down, scarcely callously
prominent ; 3, in leaves where the alar cells
are vesiculiform, the nerves obsolete, indi-
cated by a pair of very short striae, mostly
inconspicuous.

British Genera.

a. Internal peristome without interposed oilia.
Neckera, Calyptra dimidiate. Peristome

HYPNUM.

[ 408 ]

HYPOG^EI.

double, single, or absent, the internal or the
external or both bem? occasionally obsolete.
External : sixteen equidistant or more or
less geminate teeth, lanceolate, trabeculate,
with a longitudinal line, composed of a
double layer, arising below the orifice,
sometimes split into several irregular arms.
Internal : similar to the above, or capillary,
placed on a more or less exserted mem-
brane, conjoined by transverse appendages,
very often wholly or partly cancellate. No
interposed cilia.

Pilotrichum. Calyptra mitriform. Pe-
ristome, &c. as in NECKERA.

b. Internal peristome with interposed cilia.

Hookeria. Calyptra mitriform. Peri-
stome double ; external teeth lanceolate-
subulate, with a more or less broad longi-
tudinal median line, trabeculate ; internal
on a more or less deep keeled membrane,
subulate, scarcely ciliiform ; rudimentary
cilia interposed, hardly conspicuous, or,
more rarely, perfect.

Hypmim. Calyptra dimidiate. Peri-
stome double. External teeth sixteen, lan-
ceolate, trabeculate, with a more or less
broad longitudinal line, more rarely a fis-
sure, with more or less crest-like prominent
trabeculse within. Internal teeth on a
grooved reticulated projecting membrane,
lanceolate, articulated, grooved, solid or
perforated in the middle, or altogether
gaping and separating. Cilia one to four,
interposed, very often rudimentary.

HYP'NUM, Dill.— A large genus of
Hypnoideae (Pleurocarpous Mosses), here
including the species referred by modern
writers to Isothecium, Climacium, Leskea,
&c. Many of them are extremely common
in all woods, growing on trunks of trees,
banks, &c. ; others grow in water or in bogs,
&c. The distinctions of the species are
taken in great part from the forms &c. of
the leaves, which require the use of a
microscope for their accurate determination.

BIBL. Wilson, Bryol. Er. 335 ; Hooker,
Br. Flora, vol. ii. pt. 1 ; Miiller, Syn. Mus-
corum.

HYPO'CREA, Fr.— A genus of Sphse-
riacei (Ascomycetous Fungi), with a hori-
zontal, sessile, or indistinct fleshy, mostly
coloured stroma, filiform asci, and simple
spores. The species of this genus, like
those of Hypoxylon, as given by Fries, are
partly referred to Sphceria by other authors ;
the distinctions will be best explained by
taking all these genera under SPHJERIA.

HYPO'DERAS, Frauenfeld.— A genus
of Acarea (Acarina). Numerous species,
occurring beneath the skin of birds, often
forming little cysts. — Giebel, Verh. zool.-
bot. Gesell. Wien, xiv. 385; Murray, EC.
Ent. 228 (figs.); Robertson, Jn. Mic. Soc.
vi. 201.

HYPODER'RLS, R, Brown.— A genus

Fig. 351.

Hypoderris Brownii.

Sorus with fringed indusium.

Magnified 25 diameters.

of Dicksoniese (Polypodiaceous Ferns),
with very prettily fringed indusia. Exotic.
(Hooker, Syn. 46.)
HYPOG^E'L— A family of Gasteromy-

Fig. 352.

Hydnangium candidum.

Basidiospores upon the hymenium.

Magnified 400 diameters.

Fig. 353.

Hysterangium clathroides.

Section of hymenium with oval basidiospores.

Magnified 400 diameters.

cetous Fungi, characterized by their resem-
blance to the Truffles (Ascomycetes) in

HYPOLEPIS.

[ 409 ]

HYSTERIUM.

growing underground, and by their fleshy
indehiscent receptacle, which is excavated
into sinuous cavities lined with basidio-
spores. which are sometimes smooth and
sometimes tuberculated (figs. 352, 353).

See PL 27. fig. 8.

BIBL. Tulasne, L. K. & 0., Fungi Hypo-
gcei, Paris, 1851 ; Ann. Sc. N. 3 ser. xv. 267,
and Ann. N. H. 1851, vol. viii. 19; Berk.
Outl, 292.

HYPOLE'PIS, Bernh.— A genus of
Pterideae (Polypodiaceous Ferns), remark-
able as varying in the condition of the
indusiuni so as to become undistinguishable
from Polvpodium. Seven species, tropical.
(Hooker," Syn. 129.)

HYPOMY'CES, Tul.— A genus of Py-
renomycetes (Ascomycetous Fungi), pro-
posed by Tulasne to include the coloured
species which are parasitic and spring from
a thick floccose mycelium. Their conidia
are often extremely curious, and have been
referred to Sepedonium, Asterophora, Dac-
tylium, &c. The species were formerly
included in Hypocrea.

BIBL. De Bary, Bot. Zeit. 1859, 385, 393 ;*
Tul. Carp. iii. 38.

HYPOPTERYGIA'CEJE.— A family of
Pleurocarpous Mosses with a peculiar ar-
rangement of the leaves, which are placed
in two opposite straight rows united on the
upper side of the stem, with a third median
row of smaller stipuliform leaves on the

Fig. 355.

Hypopterygium.
Fig. 354. Natural size.
Fig. 355. A leafy branch. Magnified 5 diams.

under side, bearing a resemblance to the in-
termediate leaves in Selaginella (figs. 354,

355). The cells of the leaves are parenchy-
matous and equal in all parts. The genera
are all exotic, viz. Hypopterygium, Cyatho-
phorum, and Helicophyllum.

HY'POPUS, Dug.— A formerly supposed
genus of Acarina, and family Acarea.

Char. Body ellipsoidal, coriaceous ; palpi
absent; labium oblong, prolonged in the
form of a rostrum, and furnished with two
long anterior rigid setae ; the posterior pairs
of legs but little developed. The forms are
numerous, and are found as parasites upon
both animals and plants, as Arvicola (the
field-mouse), Bombus (the humble-bee),
Musca (fly), some Myriapoda, and even
upon other Acarina; also upon ferns, &c.
Dujardin supposed that they were young
forms of Gamasus; Claparede that they
were the males of certain Acarea ; while
Megnin decides that they are the nymphs
of Acari (Tyroglyphus, &c.). They have
no mouth nor digestive organs ; but are
furnished with posterior ventral suckers.

PI. 6. fig. 15 represents a Hypopus mus-
carum, which we found upon a house-fly
(Musca domestica).

BIBL. Duges, Ann. Sc. Nat. 2 se"r. i. 20,
ii. 37 ; Gervais, Walckenaer's Arachn. iii.
265 ; Dujardin, Ann. Sc. Nat. 3 ser. xii.
243 & 259 ; Claparede, Zeitschr. wiss. Zool.
1868, xviii. 445 ; Murray, EC. Ent. 231 j
Megnin, Paras. 146.

HYPOTHE'CIUM.— The term applied
to the layer of cellular tissue, on which are
attached the thecaa or spore-sacs of the
fruits of the LICHENS.

HYPOX'YLON, Fries. — A genus of
Sphseriacei (Ascomycetous Fungi), distin-
guished by a sessile stroma, separate and
distinct from the matrix (see SPHJERIA).
The Hypoxyla of Bulliard with an erect
stroma belong to XYLARIA.

HYSTE'RIUM, Tode.— A genus of Pha-
cidiacei (Ascomycetous Fungi), distin-
guished by the elliptical or elongated peri-

Fig. 356.

Fig. 357.

Hysterium degenerans.

Fig. 356. Natural size.
Fig. 357. Perithecium.

Magnified 10 diameters.

thecia (figs. 356, 357), bursting by a sim-
ple longitudinal slit. The species are nu-
merous, growing upon (usually dead) bark,

ICHNEUMONID^E.

[ 410 ]

ILLOSPOPJUM.

stems and leaves of various plants. H. ru-
ffosum has been placed by some authors
among Lichens (as Odegrapha macularis,
epiphega, Eng. Bot.). It is common on
s.nooth living branches of oak and beech.
H. pulicare, If. Rubi, H. Pini, and H. cul-
migenum, the grass- Hysterium and H.'folii-
colium, growing on leaves of hawthorn, ivy,
or oak, are common. The species with
septate spores (fig. 359) form the genus
Hysteroyraphium, Corda.

Fig. 358.

Fig. 359.

Fig. 358. Hysterium foliicplium ft Hederae. An ascus
containing eight spores, magnified 100
diameters ; with loose spores, magnified
200 diameters.

Fig. 359. Hysterium elongatum. Spores. Magnified
400 diameters.

BIBL. Berk. Hook. Br. Fl vol. ii. pt. 2.
293; Ann. N. H. 1851, vii. 185; Fries,
Sum. Veget. 368 ; Greville, So. Crypt. Ft.
pis. 24, 26, 72, 87, 88, 129 & 167.

I.

ICHNEUMON'IDJE.— A family of Hy-
menopterous Insects. The ovipositor is an
interesting microscopic object. (West-
wood, Insects, ii. 140.)

ICHTHYDI'NA,Ehr.— A family of Ro-
tatoria.

Char. No carapace ; rotatory organ sin-
gle, continuous, not lobed nor divided at
the margin.

The rotatory organ is in the form of a
circle in Ptygura and Glenophora ; in Ich-
thydium and Chcetonotus it is long, band-like,
and placed upon the ventral surface.

The family is thus divided: —

Eyes absent,
'No hairs present,

Tail-like foot simple and truncate... Ptygura.

forked Ichihydium.

Having bristly hairs,

Tail simple, truncate Dasydytes.

Tail forked Chcetonotus.

Eye single, frontal Sacculu*.

Eyes two, frontal Glenophora.

Dujardin places Ichthydium and Chceto-
notus among the Infusoria; and Ptygura
among his Melicertina.

BIBL. Ehrenberg, Infus. 386 ; Dujardin,
Inf. ; Schultze, Mutt. Archiv, 1853, 241.

lCHTHYD'IUM,Ehr.— A doubtful genus
of Rotatoria, of the family Ichthydina.

Char. Eyes absent ; body without dorsal
hairs ; pediform tail forked ; locomotion
effected by cilia placed upon the ventral
surface.

Dujardin places this genus among his
symmetrical Infusoria.

I.podura (PI. 31. fig. 23). Body linear-
oblong, often slightly constricted near the
anterior turgid and sometimes trilobate
end ; foot short ; freshwater; length 1-140".

BIBL. Ehrenberg, Infus. p. 388.

ICHTHYOPHTHI'RIUS, Fouquet.— A
genus of Holotrichous Infusoria.

Char. Subglobose ; with an anterior
suctorial disk, including converging setae.
Somewhat like Pantotrichum.

I. multi/illis (PL 53. fig. 19). Parasitic
on the trout, the loach, &c. ; forming milky
spots on the fins, gills &c. ; length 1-150".
(Kent, Inf. 530.)

IDMO'NEA, Lamx.— A genus of Infun-
dibulate Cyclostomatous Polyzoa, of the
family Tubuliporidas.

Distinguished by the erect dichotomously
divided zoary; and the tubular cells, on
one side only, in transverse rows, divided
into two sets by a median longitudinal line.

I. atlantica. Branches roundish, tapering
to a point ; cells four in each row, the
innermost tubes considerably protruded.
Height 4-10". On zoophytes.

BIBL. Johnston, Br. Zooph. 278 ; Busk,
Br. Mus. Cat., Foss. Pol. Crag (Pal Soc.) :
Hincks, Polyz. 450.

I'DUNA, 01. & Lachm.— A genus of In-
fusoria, fam. Ervilina.

Char. Those of Ervilina with a carapace,
the valves quite separate.

I. sulcata. Right valve with four raised
longitudinal ribs; left valve plane and
smooth. Northern sea. Length 1-180".

BIBL. Clap, and Lachm. Infus. p. 283.

I'DYA, Philippi= Canthocamptus, pt.,
Baird. I. furcata=C. f. (Brady, Copep.,
Ray Soc. ii. 171).

ILIOPSYL'LUS, Br. & Rob.— A genus
of Copepodous Entomostraca.

I. coriaceus. in sea-mud. (Brady, Copep.
ii. 143.)

ILLICIUM. See WINTERED.

ILLOSPORIUM, Mart.— A genus of
Stilbacei (Hyphomycetous Fungi), mostly
rose-red gelatinous bodies growing upon

ILLUMINATION.

INFLAMMATION.

Lichens, described as consisting of irregular
spores, at first involved in a globule of
mucus, and afterwards glued together in
simple mealy patches (these plants seem
very obscure). Four species are described
as British :

I. roseum, Fr. (Grev. So. Crypt. FL pi. 51) .

/. carneum, Fr. (Oorda, Ic. Fung. iii.
fig. 1).

I. corallinum, Rob. (Desmaz. Exsicc. no.
1551).

I. coccineum, Fr. (Cord. /. c. fig. 3).

BIBL. Op. cit. and Berk. Br. Flora, ii.
pt. 2, 328 ; Ann. N. H. 1850, v. 466 ; Fries,
Sum. Veg. 482 ; Syst. Myc. iii. 259.

ILLUMINATION.— This has been
specially alluded to in the Introduction
(p. xxviii), and in the articles ANGULAR
APERTURE, DIATOMACEJE, POLARIZATION,
and TEST-OBJECTS. But several papers
have been published in recent years, de-
scribing new and ingenious methods of
illuminating the finer and more difficult ob-
jects, to which we can only refer.

BIBL. Higgins, Qu. Mic. Jn. x. 150;
Abbe, M . M. Jn. xiii. 77 ; Smith, ib. 88 ;
Wenham, ib. 156, & Engl. Mechanic, 1877,
279 ; Whittell, ib. xiv. 109 ; Bramhall, ib.
xvi. 102 ; Osborne, ib. xvii. 179 ; Moore-
house, ib. xviii. 29 ; Woodward, ib. xviii.
61 ; Edmunds, ib. xviii. 78 ; Schulze, Jn.
Mic. Soc. 1878, 45.

ILYOBA'TES, G. 0. Sars (=KRITHE,
B., C., & R.)« — -^ germs °f Ostracoda (Ento-
mostraca), of the family Cytheridae. Lower
antennae 4-, upper 5-jointed, with the
last three joints short and stout ; first two
pairs of feet three-jointed; eyes wanting.

3 species. Recent in Norway, Britain,
Bay of Biscay. Fossil, Tertiary and Post-
tertiary, England.

BIBL. Brady, Crossky & Robertson,
Post-Tertiary Entom. 1874, 184.

ILYOCRYP'TUS, G. O. Sars.— A genus
of Macrotrichidae (Entomostraca).

1 species.

Britain, Russia, Germany, Sweden.

BIBL. Norman and Brady, Mon. Brit.
Entom.j Nat. H. Tr. North, vol. i. 17.

IMPERFORATA.— A division of the
Foraminifera, characterized by the absence
of pseudopodial pores or tubules in the
shell, which is either membranous (family
Gromidse), porcellaneous (fam. Miliolidse),
or arenaceous (fam. Lituolidae). (See

FORAMINIFERA.)

BIBL, Carpenter, Introd. For. 62.

INAC'TIS, Kiitz.— A genus of Oscilla-
toriacese (Confervoid Algae).

Char. Filaments sheathed, indistinctly
jointed, parallel, sometimes dichotomous,
densely aggregated, and forming a pulvi-
nate hemispherical frond, springing from a
substratum of Protococcus-likQ cells.

In pools, on other Algse ; on rocks, &c.

3 species, with several varieties.

BIBL. Kiitzing, Phyc. 77; Rabenhorst,
FL Alg. ii. 159.

INDIA-RUBBER, or CAOUTCHOUC.—
This substance occurs naturally in globules
suspended in the milky juices of many
plants, especially of the Orders Euphorbia-
ceae, Urticaceae, and Apocynaceae ; the
form, of the globules is varied. In PI. 48.
fig. 23 is represented part of a milk- vessel of
Euphorbia antiquorum with fine caoutchouc
globules. When such milky juices are eva-
porated, the globules become blended into a
uniform elastic mass, the India-rubber.

Solution of caoutchouc is sometimes used
as a cement for closing glass cells ; but its
chief importance in this respect depends on
its forming a constituent of marine glue (see
CEMENTS).

INDICATOR, QUEKETT'S.— Is a
small steel moveable hand placed just above
the diaphragm of the eye-piece, so as to point
to nearly the centre of the field.

INDIGO.— This well-known vegetable
substance is chiefly obtained from plants of
the genera Indigofera and Isatis, and Poly-
gonum tinctorium, but may be found in many
others.

It has also been found in human urine,
of which it is probably a normal consti-
tuent. Its best marked character is that of
subliming in flattened prisms and plates
(PI. 10. tig. 14).

Indigo is sometimes used as a colouring-
matter for injections, and is also very use-
ful for colouring the internal cavities of
Infusoria which swallow the granules;
also for rendering visible ciliary motion
(see INTRODUCTION, p. xxxvi), &c. - The
simplest mode of employing it is to rub it
from a water-colour cake of indigo very
gently with a little water. The Infusoria
require to be left in the coloured mixture
some time ; and it is well to remove them
into clean water for examination.

Indigo-carmine forms the basis of some
excellent staining solutions.

BIBL. See CHEMISTRY.

INFLAMMATION.— The phenomena of

INFLAMMATION.

[ 412 ]

INFLAMMATION.

inflammation are "best studied in one of the
lower animals, as in the web of the frog's
foot, the mesentery of the frog, the tail of
the tadpole, or of the larva of the water-
newt (Triton), the process being excited by
the application of a hot needle, a solution
of common salt, ammonia, dilute spirit, or
volatile oil.

The principal phenomena are as fol-
lows : —

1. Changes in the blood-vessels and circu-
lation.

2. Exudation of liquor sanguinis and mi-
gration of white blood-corpuscles ; and

3. Alterations in the nutrition of the in-
flamed tissue.

1. The first effect of irritation of the
mesentery (mere exposure to the air being
sufficient for the purpose) is to cause dila-
tation of the arteries, and subsequently that
of the veins. The dilatation of the arteries
commences at once, and is not preceded by
contraction. It gradually increases for
about twelve hours, and is associated at the
commencement of the process with an ac-
celeration in the flow of blood ; this, how-
ever, is soon followed by a considerable
retardation. These alterations in the rapi-
dity of the blood-flow, however, cannot be
owing to the increase in the calibre of the
vessels, which remain throughout dilated.

The retardation of the circulation usually
commences somewhat suddenly, and is first
observable in the veins. The rapidity of
the current varies, however, in different
vessels ; in some (both arteries and veins)
it may be more rapid, in others very slow,
and either oscillating to and fro, or even
completely stagnant. These differences may
occur in contiguous vessels. The capillaries
and small arteries often present at the same
time numerous irregular bulgings and con-
tractions.

As the circulation becomes slower, the
white blood-corpuscles (leucocytes) accu-
mulate in the veins. Their natural ten-
dency to adhere to the sides of the vessels
is increased, so that they may nearly fill the
tube. At the same time they exhibit active
movements, by means of which they pene-
trate the walls of the vessels and pass into
the surrounding tissues. The absolute
number of white blood-corpuscles may also
be increased owing to the irritation of the
lymphatic structures in the vicinity of the
inflamed tissue.

The red corpuscles also accumulate in the
capillaries. They adhere to one another

and to the sides of the vessels, and become
so closely packed that their outlines can
scarcely be distinguished. Increased ad-
hesiveness of the red corpuscles has long
been regarded as characteristic of inflam-
matory blood, by virtue of which they
exhibit a greater tendency to cohere in rolls
than in health.

The diminution in the rapidity of the
circulation, and the accumulation of the
blood-corpuscles in the vessels, is followed
by the complete stagnation of the current,
constituting the condition long known as
inflammatory stasis.

2. Another constituent of the inflamma-
tory process consists in the exudation of
liquor sanguinis and the migration of the
colourless blood-corpuscles.

The migration of the colourless blood-
corpuscles (leucocytes) through the walls of
the blood-vessels was first described by
Addison in 1842. This observer stated that
in inflammation, these corpuscles adhered
to the walls of the vessels and passed
through them into the surrounding tissues.
In 1846 Waller more fully described the
same phenomenon. Both these observers
concluded that the escaped corpuscles
became pus-corpuscles. Cohnheim in 1867
brought the subject forward ; and to him.
we owe most of our present knowledge
respecting it.

The migration may be observed in the
mesentery of a frog which has been pre-
viously paralyzed by the subcutaneous in-
jection of curare.

The colourless blood-corpuscles which
accumulate in large numbers, especially in
the veins, remain almost stationary against
the walls of the vessel, the blood-current
passing by them, although with much
diminished velocity. Those immediately
adjacent to the wall gradually sink into it,
and pass through it, between the epithelial
cells, into the surrounding tissue. In doing
so they may be observed in the various
stages of their passage. At first small
button-shaped elevations are seen springing
from the outer wall of the vessel. These
gradually increase until they assume the
form of pear-shaped bodies, which still
adhere by their small ends to the vascular
wall. Ultimately the small pedicle of pro-
toplasm by which they are attached gives
way and the passage is complete, the cor-
puscle remaining free outside the vessel.

The corpuscles having escaped from the
vessels into the surrounding tissues, continue

INFLAMMATION.

[ 413 ]

INFLAMMATION.

to exhibit active movements. They may
multiply by division, and thus rapidly in-
crease in number: this will be again referred
to when speaking of pus.

Not only is there a migration of colour-
less blood-corpuscles in inflammation, but
the red corpuscles also pass through the
walls of the blood-vessels, though in less
considerable numbers j and their transit is
mainly through the walls of the capillaries.
This passage of the red corpuscles takes
place in simple mechanical congestion j and
it may be observed in the web of a frog in
which congestion has been artificially in-
duced by ligature of the femoral vein.

Associated with the passage of the blood-
corpuscles through the walls of the vessels,
is an exudation of the liquor sanguinis.
The exuded liquor sauguinis, which con-
stitutes the well-known inflammatory effu-
sion, differs from the liquid which tran-
sudes as the result of simple mechanical
congestion, inasmuch as it usually contains
a larger proportion of albumen and fibrine,
a proportion which increases with the inten-
sity of the inflammation. It also contains
an excess of phosphates and carbonates.

The most characteristic feature of inflam-
matory effusion is the large number of cell-
structures which it contains. These are in no
case generated spontaneously in the effused
liquid. Most of them are migrated blood-
corpuscles ; and others are derived from the
proliferating elements of the original tissue.
The quantity and nature of the effusion will
thus vary with the particular tissue in-
flamed, and with the severity of the in-
flammatory process. In non-vascular tissues,
as cartilage and the cornea, exudation can
only occur to a small extent from the neigh-
bouring vessels, and hence the effusion is
small in quantity. In dense organs, as the
liver and kidney, owing to the compactness
of the structure, a large amount of effusion
is impossible ; and what there is, is so in-
termingled with the structural elements of
the organ, that it does not appear as an
independent material. In the kidney, it
escapes into the urinary tubes and so appears
in the urine. The effusion is most abundant,
and constitutes an important visible con-
stituent of the inflammatory process, in in-
flammation of those organs which possess
a lax structure and in which the vessels are
but little supported, as the lungs, and in
tissues which present a free surface, as mu-
cous and serous membranes.

3. The remaining constituent of the in-

flammatory process consists of an alteration
in the nutrition of the inflamed tissue. The
nutritive changes, although they may differ
according to the structure of the part, are
all characterized by an increase in the
nutritive activity of the cellular elements.
The nature of these nutritive changes has
for the most part been ascertained by the
investigation of tissues in the lower ani-
mals, in which inflammation has been arti-
ficially induced. In man the study of the
primary tissues is difficult, owing to the
fact that the process can rarely be observed
in its earlier stages. The alteration in
nutrition, as already stated, is characterized
by an exaltation of the nutritive functions
of the cellular elements of the tissues in-
volved in the inflammatory process. This
is evidenced by an increase in the activity
of those elements which normally exhibit
active movements, as the amoeboid cells of
connective tissue and of the cornea. Cells
which, under normal circumstances, undergo
no alterations in form, and exhibit no active
movements, become active, sending out
processes and undergoing various alterations
in shape. This increase in the activity,
and variation in the form of the cells is in
most cases followed by enlargement and
division of their nuclei and protoplasm, and
thus by the formation of new cells.

The increased activity of the cellular
elements varies considerably in different
tissues, and even in the elements of the
same tissue. Some cells exhibit active
movements, and form new cells, much more
readily than others. Those tissues, for
example, which naturally maintain them-
selves by the multiplication of their ele-
ments, as the epithelial tissues, become
active very readily in inflammation, slight
degrees of irritation being sufficient to
cause in them rapid cell-proliferation.
This is seen in inflammation of mucous
membranes, and of the epidermis. In tis-
sues, on the other hand, whose elements
normally exhibit no tendency to multipli-
cation, as common connective tissue, carti-
lage, and bone, active changes are much
less readily induced; the cells are much
more stable, and multiply with far less
facility. Lastly, in the higher tissues the
stability of the elements reaches its maxi-
mum, and in nerve-cells no increase of
activity can be induced. Different cells in
the same tissue exhibit also different degrees
of stability. In common connective tissue
and the cornea, for example, the amoeboid

INFLAMMATION.

[ 414 ]

INFUSORIA.

cells are the least stable, and are the first
to multiply. Possibly the age of the cells
may influence their tendency to become
active, the newer being less stable than the
older elements. In all cases, however, the
rapidity and extent of the proliferation are
in direct proportion to the intensity of the
inflammation. The earliest nutritive change
is thus one of cell-proliferation ; the subse-
sequent ones are characterized either by im-
pairment of nutrition and the degeneration
and death of the newly formed elements,
or by the development of these into a per-
manent tissue. The more intense the in-
flammation the greater is the rapidity of
the cell-proliferation, the more abortive are
the young cells, and the less is their ten-
dency to form a permanent tissue. In con-
nective tissues these changes in the cells
are necessarily accompanied by changes in
the intercellular substance. The latter are
for the most part characterized by softening.
In common connective tissue the fibres in
the first place become succulent and less
distinct, and ultimately they are completely
destroyed ; in cartilage the matrix softens
and liquefies ; in bone the lime-salts are
removed, the lamellae disappear, and the
osseous structure becomes converted into
medullary tissue. Hence the destructive
effect of the inflammatory process.

Those retrograde cells which undergo
fatty degeneration, are known as exudation
corpuscles (PI. 38. fig. 7).

The inflammatory exudation, consisting
of emigrant cells, which often undergo fis-
siparous multiplication, of the proper cells
of the inflamed tissue, which undergo in-
crease of size and numbers, and of the fibri-
nated liquor sanguinis, may undergo reso-
lution, organization, suppuration, and organi-
zation after suppuration : —

Resolution, by distribution of the emigrant
cells over a wider area, and their return into
the lymphatics, and by a process of fatty
degeneration of the cellular elements.

Organization, by the timely development
of blood-vessels, and the conversion of the
exudation into fibrillar connective tissue.
The cells which are not devoted to the
formation of blood-vessels, grow spindle-
shaped, and are so closely packed that they
give rise to a new variety of tissue. It
forms cylindrical or slightly flattened bun-
dles which interlace.

Suppuration. See Pus.

BEBL. Works on Medicine ; Lebert, Phys.
Pathol. ; Wedl, Path. Hist. ; Forster, Path.

An. ; Gluge, Atlas Path. An. ; Lister, Inf,.,
Phil. Trans. 1859 ; Cohnheim, Virchows
Archiv, xl. 1, and Entzundung, 1873 ;
Strieker, Qu. M. J. x. 242: Cornil and
Ranvier, Hist. Path.; Inflam., Holme's Xyst.
Surg. i. and Append. ; Virchow, Cell. Path. ;
Rin'dfleisch,Pa^. Geivebel.1878; Green,P<A

INFUNDIBULA'TA.— An order of Po-
lyzoa. (See POLYZOA.)

INFUSO'RIA.— A class of Protozoa.

Char. Microscopic animals not furnished
with either vessels or nerves, but exhibiting
internal spherical cavities ; motion effected
by means of cilia, or variable processes
formed of the substance of the body, true
legs being absent. (Body composed of pro-
teine compounds ; soluble in solution of
potash.)

Every one who has examined with a
microscope a drop of water containing ani-
mal or vegetable matter which has been set
aside for a time, or a drop from any pool or
ditch, must have observed numerous minute
beings in active motion, resembling some of
those figured in Pis. 30, 31, & 32 ; these are
Infusoria, or the animalcules of infusions.

Perhaps no question has been more dis-
cussed than that of the structure of the In-
fusoria. Ehrenberg regarded them as being
highly organized, and furnished with distinct
organs like the higher animals j whilst some
more recent authors consider them as re-
presenting simply a nucleated cell. Unfor-
tunately the facts are not accordant with
either of these views, and the question must
be considered as still sub judice.

The more or less flexible body of the Infu-
soria is usually covered with vibratile cilia,
which appear to spring from a cuticle. They
are sometimes collected in a circle around
an opening or mouth, which leads to a gullet
terminating in the soft sarcode of the centre
of the body. This central portion of the
granular and otherwise structureless sarcode
is surrounded by a denser or cortical layer,
which underlies also the cuticle. In the
cortical layer are the vacuoles and the nu-
cleus and nucleolus ; whilst in the inner
mass are the spaces which are produced by
the ingestion of food and water, and which
have been termed stomachs, whence the
former name, the Polygastrica. There is a
rotatory movement of the soft sarcode sur-
rounding these digestive spaces, which
causes them to change their positions before
they disappear. The animalcule moves
some of its cilia voluntarily ; others appear
to be in constant movement, and they are

INFUSORIA.

[ 415 ]

INFUSORIA.

the principal locomotive and ingestive or-
gans. The diversity of shape and structure
is very great amongst the Infusoria ; and it
is therefore necessary to consider the details
of the different parts composing them sepa-
rately and in order.

Intcf/ument. — The bodies of Infusoria con-
sist of sarcode, of which the outer layer
possesses usually considerably more consist-
ence than the internal portion. Cohn de-
monstrated the presence of this pellicular
layer in Paramecium by the addition of
alcohol, and noticed that the softer tissues
remained united to it by a process in one
place only, where the short gullet, which is
also lined by a continuation of the external
tissue, dips down and merges into them.
This hard transparent pellicle or cuticle is
elastic, but its contractili ty is doubted ; and
it often becomes visible when the Infusoria
are kept in a small quantity of water upon
a slide, the globules of sarcode which escape
from rupture of the body carrying it before
them. It is frequently beautifully marked
with minute depressions (PI. 32. fig. 1), re-
gularly arranged, and from each of which a
cilium arises. This cuticle must be regarded
as a secretion from the outer or cortical
layer of the sarcode ; and it is by no means
improbable that Leydig's assertion that it
arises from a layer of extremely delicate
and small cells will turn out to be correct.

Many Infusoria have a carapace or lorica,
which is in some soft and in others very hard ;
the relation of the hard carapace to the pelli-
cular layer is not, however, very distinctly
known. The carapace is often not adherent to
the body of the Infusoria, but forms a kind of
sheath for the protection of the soft tissues ;
or it may form one or two valves which are
more or less completely soldered together.
These tests are thicker and less elastic than
the cuticle ; and the peduncles which sup-
port many species of Infusoria, and which
in some instances are hollow and contain a
contractile sarcode by which they are
secreted, belong to the same kind of struc-
tures. Beneath the pellicular layer, the
substance of the body frequently appears
thicker, although no distinct layer can be
separated; and it is doubtful whether the
markings are situated in the outer coat, or
whether the latter derives them from being
moulded upon the inner coat, to which
they may properly belong.

This cortical layer (parenchyma of Cla-
parede and Lachmann), as it is called, is
firmer than the central and more diffluent

sarcode, with which it is continuous inter-
nally. It is almost homogeneous ; but an
indefinite and irregular reticulation and
fibrillation may be observed in many species,
and especially in the Vorticellae, close to
the insertion of the peduncle, with whose
contractile fibre it is continuous. The
fibrils and the so-called muscles of the
peduncle are composed of sarcode, which
has no definite structure, and which is here
and there faintly granular ; but they possess
the power of contracting more or less.
Besides these, there are the minute gra-
nule-looking cells immediately under the
pellicle (which have already been noticed),
the contractile vesicles or spaces with their
ramifications, the nucleus and nucleolus,
and sometimes chlorophyll-granules. When
present, the brightly coloured pigment-
spots, the so-called eyes, appear to be pro-
duced in this layer ; and the whole of the
cilia are continuations of it. Wright has
observed amoeboid movements in this layer.
The portion of the body which is surrounded
by and more or less continuous with the cor-
tical layer, and which is subject to rotation,
is softer and often contains granules and
corpuscles resembling fat-cells. The mouth
and gullet open into this central sarcode;
and the anus, when it exists, leads from
it. Numerous digestive vacuoles are ob-
served in this watery sarcode, which often
presents the appearance of being faintly di-
vided by films and fibres of less diffluent
protoplasm.

The existence of the outermost coat or
pellicle is demonstrated by the phenomenon
of ecdysis, which occurs in certain species.
But this does not exist in all cases ; for in
some Infusoria the body adheres readily to
the glass of the slide on which it is viewed
under the microscope, and is torn up into
fragments in the endeavour to free itself.

The cortical layer of some species pro-
duces trichocysts or thread- cells. These
are fusiform, colourless, and transparent
bodies, 1-2500" in length, arranged on the
outside of the body and perpendicularly
to it. Irritation of the surface causes them
to be transformed into long filaments ; and
they are more or less like the thread-cells
of the Polypes; but they are developed
within the cortical layer, and not as cells on
its surface.

Minute amylaceous crystalloids, coloured
blue with iodine, have been observed in
Strombidium.

Locomotive organs. — No distinct muscular

INFUSORIA.

[ 416 ]

INFUSORIA.

structure can be detected in the Infusoria,
but a contractile power is possessed by the
general substance of the body. In Vorticella
(PI. 32. figs. 21 «£ 26) and some others, the
contractile substance is prolonged through
the hollow pedicle, thus forming a spurious
muscular band.

The other directly or indirectly locomo-
tive organs are thus distinguished. 1, cilia:
these are the most common, and form the
fine, short, very transparent, hair-like fila-
ments projecting from the surface. In
some they entirely cover the surface, whilst
in others they are arranged in one or more
rows round the mouth or upon the ventral
surface, £c., as described under the genera.
During life they are seen actively vibrating ;
and in some their motion appears constant ;
whilst in others it is interrupted at inter-
vals, apparently under the influence of a
will. They are most distinctly seen when
the Infusoria are dried (see CILIA). 2, fla-
gelliform filaments (PI. 31. fig. 59), which
are long anterior cilia, the ends alone being
vibratory and movable in all directions ;
there are usually one or two only. 3, re-
tracting cilia or filaments (PI. 30. fig. 12,
18 a ; PI. 31. fig. 17) : these are single, long,
flexuous, and directed backwards ; they fre-
quently become adherent to the slide, and
produce a sudden, backward motion of the
animal. 4, setae or bristles (PI. 31. fig. 53) :
these are rigid, filiform, straight, and mo-
vable, but not vibratile, and are sometimes
provided with a bulb at the base ; they can
be slowly raised or depressed, and serve for
support, walking, or climbing. 5, styles
(PL 32. fig. 17) are thick, straight, very
movable setae, without bulbs, sometimes
having setiform branches ; they neither ro-
tate nor vibrate. 6, uncini or hooks (PI. 50.
fig. 13) are short, thick, curved, sometimes
cleft setae, serving for prehension, climbing,
or creeping, and are oulbous and usually
very thick at the base.

The long straight cirri of HaUeria (PI. 50.
fig. 12), by which the saltation of these
Infusoria is produced, probably come under
the fifth series ; but the foot of such genera
as Dysteria (Ermlia, Duj.) (PL 30. fig. 52),
which is used for locomotion, and also as a
peduncle, is the homologue of the contractile
sarcode in the hollow peduncle of Vorticella.

The flagellum of a marine Ceratium which
was observed by Claparede, suddenly disap-
peared during a rapid contraction. It re-
tracted into a spherical cavity, which was
placed close to its point of insertion.

Nervotis system. — None has been disco-
vered. In the naked Infusoria, the sense of
touch is diffused throughout the substance
of the body. In others, it is particularly
developed in the snout-like appendages of
the body, and in the longer cilia, setae, &c.
The Infusoria are probably all sensible to
light ; and many of them exhibit, near the
anterior part of the body, one or more
coloured (mostly red) specks, which have
been regarded as eyes ; but they contain
no distinguishable cornea, nor lens, nor are
they connected with any appreciable sub-
stance comparable to nervous matter.

The pigment-spot is composed of a col-
lection of minute and highly refracting
granules, and in some species it is associ-
ated with Lieberkiihn's " watchglass-like
organ." This is a very minute, transparent,
colourless and hard part of the cortical
layer, which has its convex side towards the
pigment-spot and the concave towards the
nead ; but it is not dependent on the pre-
sence of the pigment, for some species
possess it which have no pigment-spot, and
vice versa. Similar specks occur in the same
situation in the spores of man v Algae ; more-
over the eye-specks are most distinct in those
genera which are doubtful Infusoria. Hence
it may be denied that they represent eyes ;
yet they bear considerable resemblance to
the eyes of the Rotatoria and some Anne-
lida ; so that their true nature must be con-
sidered doubtful.

Digestive system. — On attentively exami-
ning Infusoria under a high power (1-4 to
1-8), a number of rounded spots are gene-
rally visible in the substance of the body ;
they are sometimes filled with a whitish
granular matter; at others they contain
Desmidiaceae, Diatomaeeae, or other Algae
or bodies existing in the surrounding water.
These have been called gastric vesicles, cells,
spaces, vacuoles, or sacculi. They are only
visible from their contents, and no mem-
brane can be distinguished in them. If a
little indigo or carmine be added to the
water containing the Infusoria, these cavi-
ties will soon become filled and will be
rendered very distinct ; in the Plates they
are represented as filled with these pig-
ments.

On attentively watching them, they will
appear to move around the body of the ani-
malcule, sometimes two of them appearing
to become fused into each other, or the con-
tents of one to pass into another. Finally,
the pigment will be seen to escape at some

INFUSORIA.

[ 417 ]

INFUSORIA.

part of the surface of the body, when the
spots will vanish.

Different views have been entertained in
regard to the nature of these spots or cavi-
ties. By the older observers, they were
regarded as internal cavities into which
water was admitted with any particles acci-
dentally suspended in it, forming a means
of bringing a greater extent of surface of
the substance of the animalcule into con-
tact with the water, and thus aiding in
respiration.

Ehrenberg regarded them as dilated caeca,
or portions of an alimentary canal (PI. 31.
tig. 38 «) j whilst Dujardin considered them
vacuoles arising in the same manner as
those found in sarcode from whatever
source derived; others have viewed them
as cells floating loosely within the body.
Most observers deny that they are portions
of an alimentary canal, and that such canal
exists, but adopt the opinion that they are
cavities irregularly formed in the substance
of the body by the introduction of the
foreign matters, which are urged through it
by its contractions, or moved onwards by its
circulation. They are certainly not cells ;
otherwise they could not so readily admit
particles of colouring-matter, &c., nor could
their contents become fused together, as is
sometimes seen to occur. They do not
appear to be simply vacuoles filled in the
ordinary manner by the surrounding liquid,
because the pigment is accumulated in them
in greater proportion than it exists in the
liquid. In many Infusoria, the particles
are admitted at a definite orifice, representing
a mouth ; this is round or oval, sometimes
situated at the anterior end of the body,
sometimes more posteriorly or even at the
commencement of the posterior third of the
body; and it is generally indicated by a
circle, fringe, or some other definite arrange-
ment of the cilia, which bring the particles
towards it. Sometimes a distinct oesophagus
lined with cilia leads to the internal sub-
stance, or to the sacculi. The course which
the particles (apparently in gastric cavities)
take is usually irregular, but sometimes
tolerably definite, down one side of the
body and up the opposite. The manner in
which the undigested particles are evacuated
is also an unsettled question; for whilst
Ehrenberg and, more recently, Lachmann
admit either the existence of a distinct ex-
cretory orifice, or evacuation by the mouth,
other authors assert that these particles
may be evacuated at any part of the surface

of the body. According to the later obser-
vations of Lachmann, the cavity of the
body of the Infusoria represents a large
digestive cavity, as in Hydra, the contents
constituting chyme, and there is a distinct
mouth and anus.

The question then must remain whether
there is a distinct alimentary canal, the
walls of which are invisible on account of
their extreme delicacy, or whether the par-
ticles drawn in by the cilia are urged at
random through the s,ubstance of the body.
The fact that distinct walls cannot be de-
tected, is of no great weight in opposition
to the former view, because the radiate
contractile vesicles of Paramecium exhibit
no walls, and are quite invisible when con-
tracted ; and the excretory vessels of Di-
stoma, although having distinct walls, are
seen to contract and then to vanish com-
pletely (Van Beneden).

It may be easily ascertained by experi-
ment that some Infusoria will imbibe bi-
sulphuret of mercury as readily as indigo or
other matters, and thus would appear to be
entirely deprived of any selecting power
governed by a sense of taste; but some
kinds would seem to have a sense of taste :
Coleps, for instance, greedily devours the
substance of crushed Entomostraca and
their ova, becoming greatly deformed in the
operation.

The vacuoles or digestive cavities are
frequently very distinct when the ani-
malcules are dead, and especially when
dried. If the animalcules be fed with co-
louring-matter, on drying them, the vacuoles
thus rendered distinct will be found to con-
tain the pigment, which is in favour of
Dujardin's view.

Surrounding the mouth in some Infu-
soria, as Nassula, Prorodon, Chilodon, and
Chlamidodon, is a horny cylinder of rod-like
bodies called teeth (PL 30. figs. 27 a, b, 29 ;
PL 31. figs. 40, 45, 72) : they do not appear
to exert any triturating power; and their
true signification is unknown. In some In-
fusoria an oesophagus is also present, as in
Vorticella, Carchesium, Epistyhs, Oxytricha,
&c., consisting of a mostly funnel-shaped
tube, often lined with cilia.

A coloured gastric juice has been de-
scribed by Ehrenberg as existing in the
gastric cavities. The colour, however, has
been accounted for by Siebold as produced
by refraction and the presence of aggrega-
tions of pigment-granules, mistaken for gas-
tric cavities. This explanation we believe

2s

INFUSORIA.

[ 418 ]

INFUSORIA.

to be inadmissible ; and in some instances,
at least (PI. 30. fig. 19), the reddish-violet
colour is real, and arises from the presence
of solution of the colouring-matter of Oscil-
latorife, which is often different by reflected
and transmitted light.

The particles of solid matter forming the
food of the Infusoria, are usually drawn to
the oral orifice by the action of the cilia.
The manner in which Actinophrys takes its
food is described under that head ; but, from
Lachmann's observations, the rays of Aci-
neta are hollow suctorial organs.

In many of the organisms included among
the Infusoria, the food-particles are ingested
at any parts of the entire surface, or at
certain parts only, no mouth being present.

Circulating system. — On closely watching
almost any of the Infusoria, minute, mostly
rounded, clear spots are seen in the sub-
stance of the body, disappearing and reap-
pearing at pretty regular intervals. These
are the contractile vesicles ; they are of var-
able size, but about that of the gastric
cavities. The nature of their contents,
which is a colourless liquid, is doubtful.
Dujardin regards it as consisting of water,
and as existing in vacuoles similar to the
vacuoles or gastric cavities ; whilst Siebold
and others find here a kind of rudimentary
circulation of a nutritive fluid, comparable
to the circulation of the blood. In certain
Infusoria, as Parameciiim (PI. 31. fig. 56),
this phenomenon is observed to take place
between a central rounded and several
elongated and radiating cavities, and the
liquid contents are seen to be propelled
from the former into the latter, and vice
versa. These contractile or pulsating vesi-
cles or spaces, as they are called, never
contain foreign particles ; they are tolerably
constant in position in the same species of
Infusoria ; and they do not rotate nor move
like the gastric cavities ; all of which facts
are opposed to the notion of identity with
the latter. The contracting vesicles of
some species open externally through a
canal ; and in others a long internal vessel is
continuous with them. They are found in
some Algae, as Volvox, Chlamidomonas,
Gonium, Syncrypta, as in Dinobryon and
Euglena, which would negative their relation
to an animal circulation. Kent, however,
considers the presence or absence of the
contractile vesicle a ready means of dis-
tinguishing unicellular animal from vege-
table organisms. Lieberkiihn and Lach-
mann describe distinct vascular branches

arising from the contractile vesicles, not
penetrating the internal sarcode of the body.

Another kind of circulation takes place
in some of the larger Infusoria. This is a
rotation of the mass of the internal sub-
stance of the body. It has been observed
in Pammecium, but only in those specimens
having green corpuscle's imbedded in the
outer coat.

When almost any of the Infusoria are
allowed to remain upon a slide until most
of the water has evaporated, rounded and
somewhat highly refractive globules will
become evident at their margins (PI. 32.
fig. 2 a) ; these consist of the semifluid
gelatinous sarcode forming the interior of
the body, and they possess a remarkable
tendency to the formation of vacuoles or
cavities within them, which apparently be-
come filled with the surrounding water.
This fact is perhaps the strongest in favour
of the formation of the gastric cavities and
contractile vesicles within the body of the
living animals in the same manner as sup-
posed by Dujardin ; which, however, is
opposed, in the case of the contractile vesi-
cles, by their tolerably constantly uniform
position, and especially their remarkable
form (as in the stellate vesicles of Parame-
(lium &c., PI. 31. fig. 56), and the manner
in which the contents in the latter instance
are propelled from one to the other, or from
the radiate to the rounded vesicles.

Nucleus. — In the substance of the bodies
of most of the Infusoria may be perceived a
solid granular-looking body, of variable
form, mostly rounded, elongate, or curved
(PI. 30. fig. 55 ; PI. 31. figs. 37, 66; PI. 32.
fig. 26), some times branched (PI. 32. fig. 25),
which those who regard the Infusoria as
consisting of simple cells consider a true
nucleus, whilst Ehrenberg regarded it as a
testis.

Nucleolus. — This is usually a small body,
in or upon the nucleus, and with a high
refractive power.

Propagation and reproduction. — The In-
fusoria increase in numbers by the following
methods: — 1. Fission or self-division. This
occurs in («) the perfect form of the animal-
cule, and (b) after it has become encysted.
2. Gemmation or budding. 3. Conjugation.

1. Fission or self-division. — (a.) Sponta-
neous division is either longitudinal (PI. 32.
fig. 37) or transverse (fig. 38). In both, the
nucleus undergoes division, as well as the
body. In the longitudinal division the pro-
cess commences at one end of the body,

INFUSORIA.

[ 419 ]

INFUSORIA.

from which the cilia usually are retracted
or disappear ; a notch is first perceived,
which afterwards "becomes deeper, until the
body is completely cleft ; the two halves
then acquire cilia, and assume the functions
of perfect animals. In the transverse divi-
sion, a median constriction appears first,
followed by perfect separation, as in the
last. During these processes of division,
the animals sometimes continue their move-
ments as usual ; at others this is more or
less interfered with. In Vorticetta (PI. 32.
fig. 21 a), in which the process of longitu-
dinal division may be conveniently watched
on account of the comparative fixure of the
animals by a pedicel, when the division is
nearly completed a ring of cilia is formed
near the attached end of the body, by the
movements of which the new Vorticella is
separated from the parent. The process is
completed in about an hour.

Claparede and Lachmann state that the
first process in the spontaneous division of
Vorticella is the development of a fresh
mouth-circle of cilia and a second contrac-
tile vesicle ; then a partial division occurs,
which is followed by fission of the nucleus
and final separation of the two animalcules.

(b.) Fission as part of an encysting pro-
cess.— Many of the Infusoria are observed to
alter their form at certain periods, become
rounded, lose or retract their cilia (PL 32.
fig. 27), and to secrete all over their surface
gelatinous matter, forming a coat or cyst
enclosing them. While thus encysted, the
substance of the body becomes divided, and
gives origin to a number of germs, w^hich
are discharged by the bursting of the cyst
(PI. 32. fig. 34). They do not then resemble
the parent, but are gradually developed,
during ordinary growth, into its form.
In some cases the progeny or brood become
individually encysted within the parent
cyst ; it appears, however, that they are not
discharged in this condition, but escape
first from their own cyst and then from
the parent, in which they leave their own
exuviae. Stein thinks that it was such
broods that Ehrenberg mistook for the re-
sults of the increase by diffluence,

In Trichoda lynceus the encysting process
appears subservient to a kind of metamor-
phosis of the individual, the animalcule
which emerges from the cyst having cha-
racters in many respects different from the
Trichoda, but no multiplication is effected
either by subdivision or gemmation. The
late Jules Haime described this multi-

plication by fission, the encysting of ova of
the separate Trichoda, and the subsequent
escape of a differently shaped creature,
which became gradually developed into a
form like Aspidisca.

2. Gemmation is not a general proces in
the Infusoria. It is well seen in Vorticella
(PI. 32. fig. 26). The buds arise from near
the posterior end of the body, and, when
fully developed, liberate themselves by the
formation of a posterior ring of cilia, as
above mentioned.

3. Conjugation. — Balbiani supposed that
male and female organs existed in many
Infusoria, the former being represented by
the nucleolus, which resolved itself into sper-
matozoa ; the latter by the nucleus, which
after sexual conjugation became converted
into ova. Later researches, however, show
that the conjugation is an ordinary fusion
of the structures of two individuals without
sexual relations. In the conjugating con-
dition, the animalcules often closelyresemble
those undergoing division. Thus Parame-
ciuin aurelia multiplies to a great extent
by self-fission, but only to a definite extent,
for sooner or later they conjugate. They
assemble upon certain parts of the con-
taining vessel, and soon become coupled in
pairs. They are closely adherent to each
other, with their similar extremities turned
in the same direction and their mouths
closely applied. While thus conjugated,
they continue moving with agility in the
liquid, turning round and round upon their
axes ; but those which, like Stentor, are
attached by a footstalk remain almost
motionless. The conjugation lasts for five
or six days. It is also stated that reproduc-
tion is effected by the breaking up of the
nucleus into fragments which subsequently
become developed into the parental form.

The metamorphosis of the Infusoria has
been noticed above ; but there is another
method by which the individual is pre-
served for a time, the encysting process
without fission. Many Infusoria at certain
times undergo an encysting process, which
apparently serves as a provision under cir-
cumstances which do not permit the con-
tinuance of their ordinary vital activity.
The movements of the Infusoria diminish
in vivacity, and the cilia are either lost or
retracted; the surface of the body pours
out a secretion which hardens around it
and the animalcule lives on and rotates
within its cyst until the time for its escape
arrives.

2E2

INFUSORIA,

[ 420 ]

INFUSORIA.

Some Infusoria live iu very briny water ;
and some can exist at a temperature of
120° Fahr.; but their numbers diminish with
the cold of winter, although a few can exist
when frozen in ice. Hardy as they are as
a class, it is therefore very remarkable to
witness the succession and disappearance of
different genera during a comparatively
short time in infusions and natural waters.

Diffusion, fyc. — When we consider that
the multiplication of the Infusoria by divi-
sion takes places according to a geometrical
progression, also that they need only be-
come encysted to produce swarms of germs,
we can easily understand their rapid pro-
pagation in liquids; when also tney will
resist a degree of cold =8° F., and an ele-
vated temperature of 260° F., or even de-
siccation, without destruction, and when
their minute size is added, we can readily
understand their almost universal diffusion.

As we have stated, a drop of water can
scarcely be found which does not contain
some Infusoria. Many of them will only
live in fresh or sweet water, whilst others
are found only in decomposing and even
putrid water containing decomposing ani-
mal and vegetable substances ; others,
again, are only met with in salt or brackish
water. Those existing in fresh water may
be collected in ordinary wide - mouthed
bottles, a drop of which may be removed
by the dipping-tube ; any individual one
perceptible to the eye may be withdrawn
by the same means. Their natural move-
ments are best watched in the live-box;
but these movements greatly interfere with
the observance of the contractile vesicles
and general minute structure, which is best
seen when they are simply confined be-
tween the slide and cover, in a small
quantity of wrater. A good plan for arrest-
ing their motions is that of warming the
slide containing them over a candle or lamp
for a short time. Many Infusoria live only
in particular kinds of infusions, just as cer-
tain plants live only upon particular kinds
of soil ; and these infusions should be pre-
pared by adding cold fresh water to the
vegetable or animal subtances (the water
being in considerable excess), and allowing
the mixture to remain for a time. Even in
infusions of many powerful poisons, as of
Nux vomica, Cevadilla, &c., they will not
be found absent; and Dujardin noticed
that their development was greatly promoted
by the addition of certain salts to the solu-
tions, as phosphate and carbonate of soda,

phosphate, nitrate, and oxalate of ammonia
(really, the more recently so-called Pasteur's
liquid) ; and this author Avas inclined to
believe that some of these salts become de-
composed in the presence of the organic
matters, yielding nitrogen to the Infusoria ;
he also states that oxalate of ammonia dis-
appears entirely under these circumstances.
The following are the most common In-
fusoria found in natural waters or infusions
of vegetable or animal matters : —

Amphileptus fasciola. Monas yidtula.

Bodo saltans. termo.

socialis. Oxytricha pellionella.

Chilodon cucullulus. Parumecium aurelia.

Chilomwias parame- chrysalis.

cium. colpoda.

Chlamidomonas pul- milium.

visculus. Polytoma uvella.

Coleps kirtus. Stylonichiapustidata.

Colpoda cucullus. mytilus.

Cyclidium glaucoma. Trachelius lamella.

Euplotes charon. Trichoda pura.

Glaucoma scintillans. TricJwdina grandi-
Leucophrys carnium. nella.

pyi'iformis. Uvella glaucoma.

Monas crepitsculum. Vorticellaconvallaria.
gliscens. microstoma.

Some of the Infusoria are phosphorescent,
and impart a luminous property to sea-
water. This has been distinctly observed
in the following species : — Prorocentrum
micans] Peridinium michaelis, P. micans,
P. fusus, P. fttrca, and P. acuminatum,
Synchata baltica, and a doubtful species of
Stentor.

Slender needle-like crystals of sulphate
of lime have been observed affixed to the
bodies of the Infusoria, probably derived
from the water in which they live.

The Infusoria are difficult of preserva-
tion. Some of them will exhibit their cha-
racters when dried, the cilia and vacuoles
remaining very distinct, as also the striae
upon the integument. Others are but little
changed by a concentrated solution of chlo-
ride of calcium, or dilute glycerine. Solu-
tion of chromic acid or of bichloride of mer-
cury will answer with some of them, al-
though they are rendered somewhat opaque
by these reagents, which is sometimes an
advantage where they are naturally very
transparent. Osmic acid has been found
very useful in killing them so instan-
taneously, that the cilia remain as in
the living state. A saturated solution of
iodine in iodide of potassium acts like osmic

INFUSORIA.

C

INFUSORIA.

acid. The juice of the common horse-shoe
geranium is a very old agent for effecting
the same purpose (Kent). The various
colouring - matters — eosine, hsematoxyline,
aniline, picrocarmine, &c. — serve to distin-

guish the nuclei &c.

The chemical properties of the sarcode
or protoplasm of the lower animals and
plants, are very important to be noted. For
although proteine matter exists' in both,
yet in the vegetable forms this is in very
small proportion, and the motile power is
correspondingly feeble. Solution of potash or
ammonia dissolves the proteine matter, and
as the animal organisms are almost entirely
composed of this, then* bodies vanish ; while
in the case of vegetable organisms, the pre-
ponderating cellulose matters remain, the
organism apparently undergoing no change.
Probably if this test were applied to the
Flagellate forms, few would be left among
the Infusoria ; and it should be used in all

The systematic arrangement of the Infu-
soria is in an unsettled state. The charac-
ters of the genera and species laid down by
Ehrenberg were mostly founded upon analo-
gies rather than upon observation. Those
proposed by Dujardin were far more accor-

dant with observation ; but unfortunately
this author so altered the names proposed
by Ehrenberg, raking up old and long-for-
gotten names, which are moreover often
doubtfully identical with those for which
they are substituted, and sometimes using
similar names for totally different genera
and species — that great confusion was pro-
duced, and the two systems are not recon-
cilable.

The later system of Claparede and Lach-
mann was a great improvement upon the
former ones ; and this has been strengthened
and improved by those of Stein and Kent,
The standard work of the latter is replete
with laborious research ; and contains de-
scriptions and figures of all the species.

In descriptions of genera and species the
anterior part of the body is that near which
the eye-specks are situated, and which is di-
rected forwards j the surface towards which
the eye-specks are nearest forms the back
or dorsal surface. A narrowing of the body
posteriorly, so as to give rise to a prolonga-
tion, forms a tail \ and an anterio'r prolon-
gation of the dorsal surface is described as
a forehead or upper lip, according to its
situation.

According to the system of Claparede and Lachmann, the Infusoria are arranged as follows : —

Noflagellum

One or more flagella

Cilia or bristles in the adult ; no suckers Order I. CILIATA.

No cilia in the adult ; suckers present Order II. SUCTORIA.

Cilia also present Order III. GlLlO-FLAGELLATA.

No cilia Order IV. FLAGELLATA.

Order I. Ciliata.

Mouth and oeso-
phagus open in
repose, the latter
ciliated, neither
dilatable ...

'Mouth and anus in a common fossa.

Mouth and anus not "» cilia
in a common fossa. I *'"

Buccal spiral laeo-
trope

Cilia all over..

Buccal spiral dexiotrope 1. Fam. -Vorticellina.

f No other locomotive organs than the

< buccal cilia 2. Fam. Urocentrina,

'" 1. Crawling locomotion 3. Fam. Oxytrichina.

/Body bell-shaped, several rows of

j buccal cilia 4. Fam. Tintinnodea.

..A Buccal spiral f Buccal cilia strong-

I forming one< est 5.

I, turn only ... [ No buccal spiral 6.

Afoot 7.

Mouth and ceso- f

phagus very dila- J Body entirely or mostly ciliated . . . •< >r « t j No carapace 8.

table; cesopha-) I '" (A carapace 9.

gus not ciliated . ( Body glabrous, one row of cilia around the mouth 10.

Fam. Sursarina.
Fam. Colpodea.
Fam. Dysterina.
Fam. Trachelina.
Fam. Coleplna.
Fam. Salteriva.

/Suckers simple
kickers not on a J
proboscis or tube.1]

Order II. Suctoria, or ACINETINA.

Not forming a f
branched colony. 1

Asheath

/Apeduncle ............... 1. Genus Podophrya.

. ^^ {Free..;;. J Gjjo;

/A peduncle .................. 4. Genus Acineta.

\Nope

Nopeduncle ............ 5. Genus Solenophrya.

Formingbranchedcolonies .......................................... 6. Genus Dendrosoma.

(.Suckers branched ................................................................................... 7. G-enus Dendrocometes.

Suckers on a long retractile tube ............................................................................................. 8. Genus Ophryodendron.

INFUSORIA.

[ 422 ]

INJECTION.

Order HI. Cilio-flagellata. PEBIDININA.

/The two portions of the cara- r Carapace with prolongations 1. Genus Ceratium.

A transverse groove < Pace e1ual in "•**& \ Carapace without appendages 2. Genus Peridinium.

) f Borders of the notch turned up and

{ The two portions unequal 4 lamelliform 3. Genus Dinophysis.

-K, _,.,. I Borders not turned up 4. Genus Amphidinium.

.No groove. Cilia on the anterior margin 5. Genus Prorocentrum,

Kent arranges the Infusoria thus : —

* FLAGELLATA.

t Ingestion by all the aurface.

Order 1. Trypanosomata. A rudimentary fla-

gellum, and an undulating membrane.
Order 2. Rhizojlagellata. A flagellum and lo-

bate pseudopodia.

Order '6. Radioftagellata. A flagellum and ra-
diate pseudopodia.
Order 4. Flagellata Panstomata. Flagella the

only motile organs,
tt Ingestive area anterior.

Order 5. Choano-flagellata, A flagellum and a

collar,
ttt A distinct mouth.

Order 6. Flagellata Eustomata. A flagellum

only.
Order 7. Cilio-flagellata. A flagellum and cilia.

** CILIATA.

Order 1. Holotricha. Cilia all over the body,

uniform.
Order 2. Heterotricha. Cilia general, but the

oral larger.
Order 3. Peritricha. Cilia forming a spiral or

circular wreath.
Order 4. Hypotrocha. Cilia ventral.

*** TENTACUMFERA (Acinetina.)
Order 1. Suctoria.
Order 2. Actinaria.

Kent defines 79 families, and 359 genera ;
of which our space will only allow a sketch
under the respective heads.

BIBL. Miiller, Animak. infusoria, 1786 ;
Ehr. Infusionsth. ; Dujardin, In/us. ; Pi-
neau, Ann. So. Nat. 3 ser. iii., v., ix. ; Stein,
In/us. ; Focke, Isis, 1836, and Physiolog.
Studien-, Meyen, Matter's Archiv, 1839;
Pritchard, Infusoria ; R. Jones, Ann. N. If.
1839, iii.; Erdl, Mutter's Archiv, 1841;
Griffith, Ann. N. H. 1843, xii. ; Siebold,
Vergl. Anat. ; Cohn, Sieb. u. Koll Zeitschr.
iii. 260 ; Kolliker, Sieb. u. Koll. Zeitschr. i.
198 ; Claparede and Lachmann, Etudes,
Geneve, 1868; Engelmann, Inftis. 1862;
Jules Haime, Ann. Sci. Nat. s. 3. t. xix.
109; Clark, Boston Mem. N. H. 1866;
Balbiani, Sexual Org. of Infus., Q. M. J.
1862, 176, 285 ; Ann. N. H. 1858, i. 435 ;
Perty, Die kleinsten Lebensformen (new
genera and species], 1852 ; Cienkowski, Qu.
Mic. Jn. v. 96; Lieberkiihn, Ann. N. H.
1856, xviii. 319; Carter, ibid, xviii. 115;
Gosse. Jn. Mic. S. 1857 ; Ray Lankester,
Qu. Mic. Jn. ; Diesing, Prothelm. 1865;
Engelmann, Geqenbaur's Morph. Jahrb.
1876; Fromental, Microzoaires, 1876 ; All-

man, M. M. J. xiv. 171; Hackel, Jen.
Zeitschr. 1873, vii. 516 (morphol} ; ibid. 561
(new marine} ; Butschli, Arch. mikr. An.
1873, and Zeitschr. wiss. Zoo/. 1878, xxx.
205; Simroth, Sch. Arch. 1876, xii. 51
(locom. appar.) ; Gruber, Zeitschr. wiss.
Zool. 1879, xxxiii. 439 (Jn. Mic. S. 1880,
282); Certes, Comp. rend. 1880, xc. 77
(glycogenesis in) ; Dallinger, Jn. Micr. Soc.
1880, iii. ].

INFUSORIAL EARTH.— The fossil
deposits of Diatoinaceae were formerly so
called.

INJECTION.— The art of filling the
vessels and other minute tubular organs of
animals with coloured substances, by which
their relative size, arrangement, and relation
to the surrounding parts may be made ma-
nifest. The substances used for injections
consist of powders, mostly insoluble, mixed
with some liquid which holds them in sus-
pension or solution ; and while in this state
they are driven into the vessels by a syringe
or some similar contrivance. We shall first
give a sketch of the apparatus requisite, and
the method of making the liquids for in-
jecting the tissues of the Vertebrata, before
treating of the process itself.

Syringe. — Two or three syringes are requi-
site, of various sizes, adapted to the volume
of injection to be thrown into the vessels, or
the size of the animal or part to be injected.
In general, one holding 6 drms. or 1 oz.,
and another holding about 2 oz. will be
found the most useful. Each syringe must
be provided with two rings at the upper
part next the handle, so that it may be
lirmly and easily held. The syringes when
in use should be surrounded by a roll or
two of flannel fastened with string, to pre-
vent their rapid cooling ; and the flannel
should be kept as dry as possible during the
process.

Sometimes a much smaller syringe, called
an oyster-syringe, is useful for injecting
very small and soft animals.

The plug of the piston is adapted to the
tube of the syringe by two pieces of wash-
leather, the method of replacing which must
be learnt at the time the syringe is bought,

INJECTION.

[ 423 ]

INJECTION.

for it is difficult of description. The plug
must work air-tight in the tube, which may
be proved by depressing the handle as far as
possible, then closing the nozzle of the sy-
ringe with one finger, withdrawing the
handle to its fullest extent, and letting it
go, whsn it should fly entirely home. If
this does not take place, the plug must be
re-leathered.

The handle of the syringe should be
graduated ; i. e. transverse lines should be
scratched upon it with the end of a file, or
in some other way, so that when its de-
scending movement is so slow as not to be
felt by the hand, it may be indicated to the
eye.

The syringes, and in fact all the mechani-
cal apparatus requisite for injection, may be
purchased of Mr. Neeves, Regent Square, or
of Mr. Ferguson, Smithfield.

The syringe must accurately fit the stop-
cocks and pipes.

Injecting-pipes. — These must be of various
sizes, to suit those of the vessels into which
they are to be introduced; they are furnished
wi,th two short transverse arms, by which
they may be tied to the vessel. The smallest
pipes which are made, easily become stopped
up unless thoroughly cleansed after use ; to
remove any obstruction,a very fine " broach"-
needle made of watch-spring is required,
and may be procured of Mr. Ferguson as
above.

Stopcocks. — One or two of these are use-
ful in stopping the injection from returning,
when the syringe is removed, or force ceases
to be applied to it.

Forceps. — One or two pairs of small tena-
culum forceps must be at hand ; these are
noticed in the INTRODUCTION, p. xxv.

Jars or other vessels for holding the in-
jection. These may consist of confectioners'
jam-pots, or may be made of tin. The
former have the advantage of retaining the
heat for a considerable time. When in use,
the jars must be placed in a water-bath, or
in a tin vessel containing water, and placed
over a stove.

Stirring-rods. — These must be made of
wood.

Size. — The colouring-matters used for
the coarser injections are mostly insoluble
powders. These are usually mixed with
size or some form of solution of gelatine,
which holds them in suspension better than
water.

The size mostly used is Young's patent
size, and it is sold in the shops. It should

be clear and fresh. Those who cannot
obtain this may prepare its equivalent by
dissolving 1 part of glue in 8 or 10 parts
of water with the aid of heat.

The principal liquid injections used may
be arranged according to their colours. In
regard to the proportions of the colouring-
matter to that of the size, it must be re-
marked that these vary as used by different
injectors; and that, in general, when the
vessels to be injected are very minute, and
the objects are to be viewed by transmitted
light, the size should be thinner, and the
proportion of pigment less, than under the
opposite conditions. When the injection
is directed to be strained, this must be done
through a piece of new flannel wrung out
of hot water, or through a "tammy sieve/'
which is more convenient. In preparing
the injections, great care must be taken
that the jars are perfectly clean, and that
no old injection remains adherent to them.
The colouring-matters, whether dry or dis-
solved, should be added to the size previ-
ously warmed in the water-bath, or the tin
vessel mentioned above; and the whole
should be stirred until thoroughly incorpo-
rated. When trituration is spoken of, it
must be understood that the rubbing in a
mortar should be continued for a long time,
until the substance is reduced to the finest
possible state of powder.

Harting recommends preparing a stronger
size than that mentioned above, containing
1 part of glue to 4 of water, and that the
chemical substances be dissolved in the
additional water requisite before being
added to the size, which would seem to be
preferable ; but we have found the method
recommended to answer every purpose, and
it has the advantage of greater simplicity.

Red Injection. — This is best made with
vermilion (bisulphuret of mercury), which
before use should be carefully examined as
to its purity from minute colourless crys-
talline particles, by viewing it by reflected
light, when they are easily detected. When
the vessels to be injected are very minute,
the vermilion is best previously levigated,
*. e. triturated in a mortar with a small
quantity of water, the whole being after-
wards thrown into a large amount of water,
and allowed to settle for a few seconds, so
that the coarser particles still left may sub-
side ; the upper portions of the liquid, con-
taining the finer parts of the powder, are
then poured off and allowed to settle, the
supernatant water being again poured off,

INJECTION.

[ 424 ]

INJECTION.

and either allowed to dry slowly, or mixed
while moist with the size.

The ordinary proportions for this injec-
tion are : —

Vermilion 1^ oz., Size 1 lb., or
Vermilion 164 grs., Size 4 oz.

Stir the colouring-matter well with the
warmed size, then strain.

Other red colouring-matters have been
used, but they cannot be recommended.
Among them may be mentioned : — the basic
chromate of lead, prepared by boiling the
neutral chromate with caustic or carbonate
of potash ; the biniodide of mercury, formed
by decomposing bichloride of mercury with
iodide of potassium in atomic proportions ;
and the oxysulphuret of antimony.

Yelloio Injection. — This is prepared with
the chromate of lead (chrome-yellow), as
follows : —

Take of

Acetate of lead 380 grs.

Bichromate of potash 152 grs.
Size 8 oz.

Dissolve the lead-salt in the warm size,
then add the finely powdered bichromate of
potash.

As thus prepared, some of the chromic
acid remains free, and is wasted, which may
be obviated by preparing the chromate of
lead with the chromate of potash in the
proportions of

Acetate of lead 190 grs.,

Chromate of potash (neutral) 100 grs.

Size 4 oz.

or

Acetate of lead 196 grs.

Bichromate of potash 76 grs.

Carbonate of potash 41 grs.

Size 4 oz.

Thiersch used chromate of potash and
nitrate of lead.

The chromate of lead prepared from the
bichromate of potash alone has the deepest
colour, and is that generally used.

White Injection. — The best white injec-
tion is made with carbonate of lead, thus :
take of

Acetate of lead 190 grs.

Carbonate of potash 83 grs.

Size 4 oz.

Dissolve the acetate of lead in the warm
size and filter; dissolve the carbonate of

potash in the smallest possible quantity of
water, and mix it with the size.

143 grains of carbonate of soda may be
substituted for the above amount of carbo-
nate of potash.

A white injection (very inferior) may also
be made with carbonate of lime, by taking
of

Fused chloride of calcium .. Ill grs.

Carbonate of potash 167 grs.

Size 4 oz.

28G grs. of carbonate of soda may be substi-
tuted for the carbonate of potash.

Blue Injection. — In whatever manner
prepared, this cannot be in general recom-
mended ; for blue pigments reflect so little
light, that the injections made with them
appear almost black. The only one worthy
of mention is prussian blue suspended in
oxalic acid, which may be prepared with

Prussian blue 73 grs.

Oxalic acid 73 grs.

Size 4 oz.,

the oxalic acid being first finely triturated
in a mortar, the prussian blue and a little
water afterwards added, and the whole
then thoroughly mixed with the previously
wanned size.

General method. — When the part for
injection has been selected, the first pro-
ceeding is to fix the pipe in some vessel; and
the larger this is, the more easily will the
pipe be inserted and fixed. When the vessel
has been isolated, if it has been cut across,
the pipe should be introduced at its end,
pushed up as far as possible, and a piece of
not too thin silk thread passed beneath and
tied around it, enclosing of course the nozzle
of the pipe ; the ends of the silk should then
be wound round the arms of the pipe and
again tied, so that the pipe may remain
firmly fixed in the vessel. If the vessel be
not divided, a longitudinal slit should be
made in it for the introduction of the pipe,
the thread being passed round it by a
curved needle, the eye of which carries the
thread. As soon as the pipe has been fixed
in the vessel, all other vessels communi-
cating with it should be tied round with
silk thread or closed in some other way, that
the injection may not escape : sometimes it
is requisite to enclose a part of the tissue
itself in the ligature ; in other instances
their closure may be effected by fusion of
the tissue at the spot from which the injec-
tion might escape, by the application of a
red-hot iron.

INJECTION.

[ 425 ]

INJECTION.

The organ or part to be injected is then
immersed in warm water, in order that it
may become heated throughout ; and if it
be large and of considerable thickness, this
may take some time ; and fresh warm water
must be added at intervals to keep it at the
same temperature, which should be about
as great as can be borne by the hand. If
the water be too hot, the vessels and tissues
will be rendered brittle, and the whole will
be spoiled. Moreover the part should not
be kept longer in the water than is absolutely
requisite, for the same reason. While the
tissue is becoming heated in the water, the
injection should be prepared, or be heated
if previously prepared, and kept constantly
stirred; the stopcocks should also be im-
mersed in hot water.

As soon as all is ready, the stopcock
turned open, is fixed to the syringe, and
some hot water is drawn into and expelled
from the syringe two or three times, so that
it may become properly heated. It is next
filled with the injection, taking special care
that no air be allowed to enter, to avoid
which it must be filled, emptied, and refilled
several times, the nozzle being kept beneath
the surface of the injection. The syringe is
then taken in the hand, a little of the injec-
tion being forced out at the nozzle of the
stopcock, which is next loosely inserted
into the pipe ; and some of the injection
being urged into it by depressing the handle,
the pipe is filled, and the nozzle introduced
'into it. Very gentle pressure is then made
upon the piston, so that the injection may
be driven into the vessels ; and this must be
continued until the piston ceases to be felt
to move, or is seen not to enter the syringe
further, by watching the graduations on its
handle. 'When this is found to be the case,
firmer pressure must be made and the effect
noticed. But practice can alone guide as to
the time at which the pressure should cease,
or when as much injection has been forced
into the preparation as is required. Some
judgment may be made from the colour
assumed by the preparation ; or, the stop-
cock being turned off, and the syringe sepa-
rated from it, the preparation may be exa-
mined with a low power, while laid upon a
large glass plate.

During the continuance of the process,
the preparation, the injection, and the pipes
must be kept at the original temperature ;
and should any part be found to become
cool, the stopcock must he turned off, the
syringe separated, the injection returned to

the jar, fresh warm water added to the
preparation, and the whole process recom-
menced as at first.

If, during the process, there should be an
escape of the injection from any part, this
need not cause alarm if slight ; should it,
however, be considerable, it must be stopped
by one of the means pointed out above —
perhaps by the orifice of the vessel and sur-
rounding parts being grasped by the tena-
culum-forceps, and the whole included in a
ligature. If the preparation be small, not-
withstanding a considerable escape of the
liquid, a very good injection may often be
made.

As soon as the injection is completed, a
ligature should be placed around the vessel
into which the pipe is inserted, beyond its
nozzle ; the pipe is next removed, and the
preparation should be immersed in clean
cold water, and kept in it for an hour or
two at least. It may then be withdrawn
and sections made of it with a knife, razor,
or some other instrument.

Large pieces of injected preparations are
best preserved in a stoppered bottle con-
taining dilute spirit of wine (1 spirit to 2
water, or equal parts). See also PRESER-
VATION.

When two or more sets of vessels are to
be injected, the process should be continued
uninterruptedly until completed; i. e. as soon
as the injection of one set has been com-
pleted, another pipe should be at once in-
serted into one of the other set, and so on.
Or what is better, if possible, the pipes for
the two or three sets should be introduced
and fixed at once, before the process is com-
menced.

As regards the period after death at which
the injection should be commenced, this
varies with the kind of organ or tissue : if it
be delicate, the sooner the better ; whilst if
the vessels be comparatively large, by some
little delay the tissue becomes somewhat
softer and more yielding.

When a tissue has been successfully in-
jected, the vessels appear plump and well
filled by reflected light. But if they are not
so, the preparation has its value; for it will
perhaps well display the relative positions
of the capillaries to the surrounding tissues
when viewed by transmitted light — often
even better than when the injection has
been what is termed successful. In fact,
when the vessels are well filled, little more
can be seen in general than the relative
situation of the vessels to each other,

INJECTION.

[ 426 ]

INJECTION.

The choice of the kind of injection is not
a matter of much importance, except as
regards the facility with which the vessels
are filled. The arteries are in general filled
with red injection, the veins with yellow,
and the ducts (as the urinary tubules) with
white. The chromate of lead is perhaps
the finest injection and runs best, except
that made with prussian blue and oxalic
acid, which does not reflect enough light
where the vessels are to be viewed by re-
flected light, although when these are very
minute and can be conveniently viewed by
transmitted light it may be preferred.

It may be remarked that, if it be required
to use a yellow (the chromate) injection
and a white (the carbonate of lead) for
two sets of vessels in one preparation, the
chromic acid in the former must previously
be completely neutralized; otherwise it will
render the white (carbonate of lead) yellow.
This may, however, be avoided by substi-
tuting the carbonate of lime for that of lead.

As microscopic objects, nothing can ex-
ceed the beauty of injected preparations;
and to be seen in their greatest perfection
they should be dried, moistened with oil of
turpentine, and mounted in Canada balsam.
At the same time it must not be forgotten
that, when dried and preserved in this man-
ner, the real arrangement of the vessels is
more or less distorted, those lying in dif-
ferent planes being brought into the same,
and so on.

In Plate 39. figs. 33, 34, and 35, we have
given representations of three injections
viewed by reflected light, — fig. 33 being
taken from the liver of a cat, in which in-
jection made with vermilion was thrown
into the portal vein, and that with chromate
of lead into the hepatic vein ; fig. 34 is a
portion of the lung of a toad injected with
vermilion ; and fig. 35 is a portion of the
kidney of a pig, the arteries and Malpighian
tufts (KIDNEY) being filled with the red
(vermilion) injection, and the urinary tu-
bules with the white (carbonate of lead).

Self-injection occupies an important posi-
tion amongst the various modes. The vas-
cular system of the frog may be injected by
inserting a pointed glass tube filled with
the coloured injecting fluid into the vena
cava. The fluid passes into the heart, and
is distributed through the system by the
force of the heart itself. The biliary vessels
of living animals have been injected by
means of colouring-matter introduced into
the jugular veins.

Toldt has injected the lymphatics on this
system ; and he introduces a granular pig-
ment (aniline) precipitated by water from its
alcoholic solution into the blood.

The perfect injection of an organ or an
entire animal of considerable size is a
tedious and fatiguing process. We have
therefore contrived a very simple piece of
apparatus, which any one can prepare for
himself, and which effects the object by
mechanical means. It consists of a rect-
angular piece of board, 2' long and 10" wide,
to one end of which is fastened an inclined

Fig. 360.

piece of wood supported by two props, as
shown in fig. 360. The inclined portion is
pierced with three holes, one placed above
the other, into either of which the syringe
may be placed — the uppermost being used
for the larger, the lowermost for the smaller
syringe ; and these holes are of such size as
freely to admit the syringe covered with
flannel, but not to allow the rings to pass
through them. The lower part of the
syringe is supported upon a semiannular
piece of wood, fastened to the upper end of
an upright rod, which slides in a hollow
cylinder fixed at its base to a small rect-
angular piece of wood ; and by means of a
horizontal wooden screw, the rod may be
made to support the syringe at any height
required. The handle of the syringe is let
into a groove in a stout wooden rod con-
nected by means of two catgut strings with
a smaller rod, to the middle of which is
fastened a string playing over a pulley, and
at the end of which is a hook for supporting
weights, the catgut strings passing through
longitudinal slits in the inclined piece of
wood.

In use, the part to be injected is placed
in a dish of some kind containing warm
water, supported at a suitable height beneath
the end of the syringe by blocks of wood.
The syringe is then filled with injection,
passed through the proper aperture in the

INJECTION.

[ 427 ]

INJECTION.

inclined board, and fitted to the pipe, the
stopcock being turned off. The rod and
strings are next adjusted, and, a suitable
weight being added, the stopcock is very
slowly turned on, and the effect watched.
If the handle of the syringe does not move,
more weight must be added, the stopcock
always being turned off when this is about
to be done.

A great advantage of this apparatus is,
that it sets at liberty the hands, so that an
escape of injection may be arrested, or fresh
warm water added, without interruption of
the process.

Other automatic methods have been pro-
posed, as that of Rutherford, which is
this : —

A large jar of water is attached to a
pulley, so that it can be elevated to any
height. A long elastic tube with a stopcock
is connected with the interior of the jar,
near its bottom, so that the water may flow
out when required. The other end of this
tube transmits the water into a large
Woulfe's bottle having three apertures.
The water flows in by one aperture, through
a glass tube which passes to the bottom
of the bottle. The air is thereby forced
through the other two apertures, one com-
municating with a mercurial manometer for
indicating the pressure, the other transmit-
ting the air through an elastic tube to a
second Woulfe's bottle containing the injec-
tion. This bottle has two apertures. The
air is forced upon the surface of the liquid,
and a glass tube, reaching nearly to the
bottom of the bottle, transmits the injection
to an elastic tube joined to a glass or metal
nozzle placed in the vessel. Any number
of Woulfe's bottles may be added, so that
different injections can be thrown in at the
same time. The pressure can be regulated
with the greatest nicety.

When it is not required to fill the capilla-
ries, but only the smaller arteries or veins,
the colouring-matters need not be prepared
by double decomposition, and the following
substances may be used : —

Red. — Size 1 lb., vermilion 2 oz.
Yellow.— Size 1 lb., King's yellow

(orpiment) or chrome-yellow 2| oz.
White.— Size 1 lb., flake-white 3| oz.
jS/we.— Size 1 lb., fine blue smalt 6 oz.
Black. — Size 1 lb., lamp-black 1 oz.

Injections made with transparent solu-
tions are now largely used, the objects being
viewed with high powers, by transmitted

light. Fine gelatine is usually employed,
and is dissolved in water over a water-bath,
the colouring-matter already in solution
being then added, and the mass introduced
into a Woulfe's bottle, which must be im-
mersed in a warm water-bath. The injec-
tion takes long to do; and the warmth must
be kept up. The colouring matters usually
employed are prussian blue and carmine —
the latter not in a state of complete solu-
tion, but partly precipitated by the addition
of a little weak acid from its alkaline solu-
tion. Thiersch, whose transparent injec-
tions are wonderful, uses a transparent yel-
low, and green, — the former from chroniate
of potash and nitrate of lead, and the latter
from a mixture of this with blue. Beale,
in order to avoid the injecting of warm
fluids, uses colouring-matter, water, glyce-
rine, and traces of hydrochloric acid ; after-
wards the injected mass is placed in absolute
alcohol.

Carter's carmine injection is made thus :
— dissolve 60 grains of pure carmine in 120
grains of Liq. Ammon. fort., and filter if
necessary; mix with this 1| oz. of hot
solution of gelatine (1 to 6 of water) ; mix
another £ oz. of the gelatine solution with
86 minims of glacial acetic acid, and drop
this little by little into the solution of car-
mine, stirring briskly the whole time. Dry,
or harden in solution of chromic acid ; cut
with a sharp razor, and mount in Canada
balsam.

Beale's fine blue injection is made with

Glycerine 1 oz.

Spirit of Wine 1 oz.

Ferrocyanide of potassium .... 12 gr.

Tinct. or sol. of perchlor. iron . . 1 or.

Water 4 oz.

Dissolve the ferrocyanide in 1 oz. of the
water and the glycerine, and the iron in
another oz. Mix gradually, adding the iron
to the ferrocyanide. Then add the spirit
and the rest of the water.

For very fine injections, the mixture may
be diluted with 3 oz. of glycerine, and half
the quantity of ferrocyanide and iron used.

The ferridcyanide of potassium is often
used, forming Turnbull's blue, which is
brighter and less liable to fade. This is
made with ferridcyanide of potassium
10 grs., sulphate of iron 5 grs., glycerine
2 oz., water 1 oz., and alcohol 1 drachm.

Numerous other fine injections are de-
scribed by Beale and Frey.

INJECTION.

[ 428 ]

INOMERIA.

The tissues of the Invertebrata are so
soft, that the ordinary syringes and pipes
can rarely be used for injecting them, and
recourse must be had to a finer and lighter
form of apparatus. This may consist of a
fine trochar, with a needle. In using it,
the small vessel through which the injection
is to be thrown, is held with forceps against
the end of the trochar, and punctured with
the needle. The trochar is next directed
into the puncture, and the needle withdrawn.
The small nozzle of a syringe is then intro-
duced into the upper end of the trochar,
and the injection thrown in. A form pro-
posed by Harting consists of a common
glass pipette of moderate width, and of a
caoutchouc tube the smaller end of which is
fastened by means of thread to the broader
end of a fine, curved, glass nozzle. In using
this apparatus, the pipette is first filled with
the injection, and its lower portion intro-
duced into the broader end of the caout-
chouc tube, which, from its conical form, it
accurately closes.

Different liquids for injection are also
usually requisite ; and many have been re-
commended. Among these may be men-
tioned : — 1, indigo, triturated with oil and
diluted with oil of turpentine ; 2, oil-paints
diluted with oil of turpentine ; 3, infusion
of logwood (Hcematoxylori)^ ; 4, solution of
carmine in size or in ammonia ; and 5, solu-
tion of alkanet in turpentine.

A considerable escape of the injection is
often unavoidable in these cases, and must
therefore not be heeded.

Some injectors simply introduce the in-
jection into the dorsal vessel or lacunae,
whence it is propelled to all parts of the
body by the circulation. Thus Agassiz
says that if the indigo injection (1) be in-
troduced in this way into insects, it is seen
to circulate almost instantaneously in every
part of the body, and on subsequently open-
ing the insect all parts of the body are
found to be coloured. We believe that
Blanchard also adopts this method. Pro-
bably the best injections for this purpose
would consist of alkanet and turpentine.

Injections may be preserved either in the
dry or wet state. For the former, sections
should be made, thoroughly dried upon
slides, then moistened with oil of tur-
pentine, and mounted in balsam. For pre-
servation in the wet state they must be
mounted in cells while immersed in dilute
spirit, Goadby's B. solution, or in chloride
of zinc (see PBEBEBVATION).

We have not space to give a list of
injected preparations; they are all very
beautiful, but we can only 'notice a few of
the most interesting. For practice in the
art of injecting, we may recommend the
kidney of a sheep or pig, — one system of
vessels being alone filled with red or yellow
injection ; and this should be the arterial.
Afterwards, in another kidney, the urinary
tubules may be injected first, with white
injection, and subsequently the arteries with
red or yellow. A portion of the small
intestine, exhibiting the general capillaries,
with the plexuses of the villi, forms a
beautiful object as prepared from the rabbit,
the rat, <fcc. Among other preparations
may be mentioned: — the liver of various
animals, as the cat, the rabbit, &c. ; the
lungs of the cat, rabbit, &c.r in which the
capillaries are very minute ; those also of
reptiles, as the frog, triton, boa, and other
snakes, in which they are coarser, but very
beautifully arranged; the lungs of birds';
the kidneys of the frog and triton ; the web
of the frog's foot ; the ciliary processes and
choroid coat of the eye ; the 'gills of the eel
and other fishes ; the lungs of kittens, &c.
which have not breathed, the air-cells being
injected from the trachea ; the skin of the
frog, and especially of the triton, &c.

BIBL. Tulk and Henfrey, An. Manip. ;
Robin, Microscope ; Quekett, on Inject ;
Goad by, in Wythes's ' Microscopist-, ' Beale,
How fe.j Rutherford, Hist. 1876; Mose-
ley, Q. Mic. Jn. 1871, 389, Inject. Insects-,
Frey, Mikr. 1881.

INODER'MA, Kiitz.— A genus of Pal-
mellaceae (Confervoid Algae).

Char. Cells oblong, usually in longi-
tudinal rows, loosely united by a soft jelly ;
thallus gelatinous, membranous, irregularly
expanded.

/. lameUosum. On submersed wood and
stones, everywhere.

BIBL. Rabenhorst, Fl. Alg. iii. p. 37.

INOME'RIA, Kutz.— A genus of Oscil-
latoriacese (Confervoid Algae) with calca-
reously hardened incrusting fronds, growing
on stones in fresh water. Fronds composed
of vertical, parallel, whip-shaped filaments,
with the sheaths obscure, connected to-
gether, and decomposed into very slender
fibrils above. Kiitzing supposes his /. Rce-
meriana to be synonymous with Hassall's
Lithonema crustaceitm.

BIBL. Kiitz. Sp. Alg. 343, Ic. Phys. ii. pi.
83 ; Hassall, Alga, 266, pi. 65. fig. 3 ; Ra-
benhorst, Fl. Alg. ii. 223.

INOSITE.

[ 429 ]

INSECTS.

I'NOSITE. — Or muscle-sugar, is a colour-
less crystalline substance, occurring in the
muscular tissue of the heart, in the liver,
the lung, kidneys, and brain ; and in plants,
in grape-juice, wine, and haricot-beans.
The crystals form rhoinbohedra, and are
soluble in water, but not in alcohol or ether.

INSECTS.— A class of invertebrate arti-
culate animals.

Char. Head distinct, furnished with two
antennae ; three pairs of legs ; respiratory
organs consisting of tracheae ; cutaneous
skeleton composed of chitine.

Insects are distinguished from the Arach-
nida by the head being distinct from the
thorax, and the presence of antennas ; and
from the Crustacea by the respiratory organs
consisting of tracheae.

The body consists usually of thirteen seg-
ments or somites — one for the head, three
for the thorax, and nine for the abdomen,
the legs being attached to the second, third,
and fourth segments.

The cutaneous skeleton or integument of
insects probably consists of three layers — an
outer epidermic, an intermediate pigment,
and an internal fibrous layer ; but consisting
as it does of chitine, it is very imperfectly
resolvable into its elementary components.
The epidermic layer of ten presents a distinct
cellular aspect (PI. 35. fig. 30 «), sometimes
the cells appearing as if flattened and over-
lapping (PI. 35. fig. 30 c) and their free
margins fringed with minute hairs (fig. 30 6).
In other instances the epidermis appears
uniform and structureless. In its deeper
portion the epidermis is often strongly co-
loured by a resinous pigment, which is
removable by prolonged maceration in so-
lution of potash or in oil of turpentine. Be-
neath these imperfectly separable layers, is
another representing probably the cut is, and
consisting mostly of numerous secondary
layers made up of fibres, running parallel or
interlacing, and leaving fissures and tubes
between them, sometimes presenting a stel-
late appearance : these fibres may be sepa-
rated by maceration in caustic potash.

The outer surface of the integument of
insects is usually furnished with processes
of various kinds,' as tubercles, hairs, spines,
scales, &c. (see HAIRS and SCALES). The
inner surface also gives oft' processes, which
form a kind of internal skeleton, serving for
the attachment of muscles, &c. In sketch-
ing the various parts of which the skeleton
is composed, it must be understood that
they are not always equally distinct, and

that upon their degree of development, form,
and general structure the characters of the
families, genera, and species are mainly
founded.

The head (fig. 361 «) consists of an upper
anterior portion (PI. 33. fig. 1 d), the clypeus,
and an upper posterior portion (fig. 1 o), the
epicranium or vertex, which are sometimes
separated by a suture ; a posterior portion
or occiput (fig. 2+), by which the head is
articulated with the prothorax ; and a pos-
terior inferior portion (fig. 3 ri), the gula.

The eyes are situated upon the upper, an-
terior, or lateral parts of the head, and are
of two kinds, simple and compound. The
simple, called ocelli or stemmata (PI. 35. fig.
2 «; PI. 33. fig. 24 6), are usually from one
to three in number, but sometimes are
numerous in larvae ; they appear like shining
smooth specks (PI. 33. 'fig. 4), and usually
form a triangle behind or between the com-
pound eyes. They consist of an arched,
round, or elliptical cornea, behind which is
a conical or cylindrical lens, which is sur-
rounded by a layer of pigment of various
colours, resembling a choroid membrane,
and is in connexion with a filament of the
optic nerve.

The two compound eyes (fig. 361 5) are
large, usually round or kidney - shaped
(PI. 33. figs. 1 c, 3 c), situated upon the
upper and outer part of the head, and are
sometimes so large (as in the Diptera, Li-
bettula, &c.) as almost or quite to touch
each other in front. They may be regarded
as composed of numerous simple eyes closely
aggregated ; their corneae vary in thickness,
are but slightly arched, quadrangular or
hexagonal in form, and in immediate con-
tact laterally. Hence the compound cor-
nea, when viewed from before or behind,
presents the appearance of a membrane with
numerous beautifully regular six- or four-
sided facets (PI. 33. figs. 5 a, 5). The facets
are very variable in number ; but often many
thousands are present. They are occasion-
ally broader in front than behind, and are
sometimes doubly convex (as in the Lepi-
doptera), at others concavo-convex (in Li-
bellula, PI. 33. fig. 6 c) ; but usually the sur-
faces are parallel. The cornea possesses a
laminated structure.

Behind each cornea is a transparent cone
(PI. 33. fig. 6 *), representing a crystalline
lens, the apex of which is imbedded in a
transparent rod or pyramid laminated in
structure, corresponding to a vitreous hu-
mour j and this is probably continuous with

INSECTS.

[ 430 ]

INSECTS.

a branch of the optic nerve. The length of
the lens is variable, in the Diptera being
very short, whilst in the Coleoptera and
Lepidoptera it is five or six times as long

as broad, and in Libellula it even exceeds
this length. The compound cone, consist-
ing of the lens and vitreous humour, is sur-
rounded by a sheath of pigment, forming a

Fig. 361.

Diagram showing the principal parts of the cutaneous skeleton of a grasshopper.

a the head, with the eyes 6 and the antennae c; d, the thorax, consisting of e the prothorax, to which the first pair
of legs^are attached ; g, the mesothorar, to which the first pair of wings h, and the second pair of legs t are attached ;
k, the metathorai, to which the second pair of wings I, and the third pair of legs m are attached; n, abdomen ; m,
femur ; o, tibia with its spines, and p tarsus with its claws.

the submentum (fig. 3m); at others this is
consolidated with the occiput (fig.27w). The
most anterior portion is the ligula (figs. 2,
3 t), which is frequently notched or lobed,
and is sometimes furnished with two lateral
portions called paraglossae (fig. 2*). Between
the ligula and the mentum or submentum
are the palpigers, one on each side (fig. 2 i) •
these are sometimes united, and to them
the labial palpi (figs. 2, 3 k) are attached.
Below the labrum are the mandibles, one on
each side, forming two strong curved jaws,
and frequently furnished with powerful
teeth (figs. 3/, 22 6); these are the proper
organs of manducation. Below the mandi-
bles are two other lateral organs, the maxillae
(figs.^1, 2, 3g-, fig. 22 c) ; they are usually
less firm than the mandibles, and serve to
hold and convey the food to the back of the
mouth. Each maxilla is furnished with a

choroid membrane (PI. 33. fig. 6r), in which
numerous tracheae ramity j this extends over
the front of the base of the cone, leaving,
however, a small pupillary space or pupil,
which is separated from the back of the
cornea by an anterior chamber.

The antennce are noticed under ANTENNA.

The trophi or organs of the mouth vary
in structure in the different orders, but the
following form the typical parts : an upper
central single piece, the labrum, or upper
lip (PI. 33. figs. le,3e, 22 a), forming the
upper boundary of the mouth, and articu-
lated at its base with the clypeua. A lower
single piece, forming its lower margin, called
the labium or lower lip (PL 33. fig. 2 t, /, m).
This consists of several parts : the most
posterior is the mentum (fig. 3 I), which is
articulated posteriorly with the gula (fig. 3 M).
Sometimes an intermediate portion occurs

INSECTS.

[ 431 ]

INSECTS.

jointed palp (figs. 1, 2, 3 /*), and sometimes
with an appendage called the galea or
helmet (fig. 22 *), and an inner curved and
acute portion termed the lacinia or blade
(fig. 22 1). In some insects there is a di-
stinct soft and projecting organ, forming the
floor of the mouth, the lingua or proper
tongue (fig. 22 d) ; the tongue of the cricket
(fig. 23) is a favourite and beautiful micro-
scopic object.

These structures are best examined in the
Coleoptera or Orthoptera, in which most of
these parts are distinct. In the other orders
they are altered in structure to adapt them
to the nature of their food.

Thus in the Lepidoptera, the labrum and
mandibles are reduced to three minute tri-
angular plates ; the maxillae are elongated
to form the antlia (ANTLIA), at the base of
which a pair of minute palpi are often to be
detected. The labium is small, triangular,
and furnished with a pair of large palpi
clothed with long hairs or scales, and serving
for the defence of the antlia.

In the Hemiptera (PI. 33. figs. 26, 27),
the labrum is short and pointed, and over-
laps the root of the rostrum ; the mandibles
and maxillae are transformed into slender
lancet-like organs (the maxillary palpi being
obsolete), enclosed within the equally elon-
gated horny and jointed rostrum or labium,
the labial palpi also being obsolete.

In the Diptera (PL 33. figs. 29, 30), the
five upper organs, together with the internal
tongue, are elongated into lancet-like organs,
the maxillary palpi being attached to the
base of the maxillae. These six organs are
enclosed in a fleshy thickened piece, the
labium, often terminated by two large lobes
which act as suckers. In many species,
however, some of these lancet-like organs
are obsolete. This kind of mouth is termed
a proboscis.

These varieties are further noticed under
the heads of the genera selected for illustra-
tion.

Behind the head is the thorax. This
consists of three rings or pieces, each of
which supports a pair of legs (fig. 361 e, g,
k). The first ring is called the prothorax
(e), the second the mesothorax (g), and the
third the metathorax (k). Each of these
rings consists of a dorsal and a sternal piece ;
the dorsal half-rings are called the pro-
notum, mesonotum, and metanotum; the
ventral or sternal the prosternum,' rneso-
sternum, and metasternum. In the four-
winged insects, the anterior wings are

attached to the central piece or mesothorax
(g), the posterior wings to the metathorax
(k). In the Diptera, the wings are attached
to the mesothorax, and the halteres to the
metathorax. Various other subdivisions
have been made of these parts, but they are
too numerous to mention here. It may be
remarked, however, that the epimera are the
pieces to which the basal joints of the legs
are directly attached ; that the under part of
the thorax or pectus is sometimes furnished
with an elongated acuminate appendage, the
sternum ; and that the scutellum or shield
is a piece existing at the upper and back
part of the mesonotum, and extending be-
tween the wings.

The legs (usually called feet) are placed
on the underside of the body, and are joined
to its segments at an articular cavity exist-
ing between the sternum and the epimeron,
called the acetabulum. Each leg usually
consists of five parts. The first is the hip
or coxa (PI. 35. fig. 9 g) ; but sometimes
there is a small very moveable piece between
the epimeron and the coxa (PI. 35. fig. 9,
between / and g), called the trochantin ;
this, however, is generally absent or con-
solidated with the coxa. 'The second joint
is the trochanter (PI. 35. fig. 9 7^) ; it is
mostly small, and annular. The third is the
thigh or femur (fig. 361 m ; PI. 34. figs. 4,
5, 7 d), the thickest and usually the largest
joint of the leg. Next comes the fourth, the
tibia (fig. 361 o ; PI. 34. figs. 4, 5, 6, 7 c),
which is thinner, usually compressed, and
frequently furnished with spines, spurs, or
other appendages, especially at its end ; in
the ant the tibiae have each a beautiful
pectinate process. The last portion is the
foot or tarsus (fig. 361 p ; PI. 34. figs. 6, 7 a),
which consists of several joints arranged in
a row. The number of these j oints varies in
different insects ; sometimes it is different
in the anterior and posterior pairs of legs ;
they are, however, most commonly five.
The last joint of the tarsus is usually fur-
nished with appendages, in the form of
hooks or claws, mostly two, and frequently
serrated, especially near the base. Some-
times also it has two or three delicate mem-
branous or fleshy cushions, called pulvilli
(PI. 34. figs. 7 & 8) ; these are more or less
covered with hairs, which are sometimes
terminated by little disks (fig. 9), and by
which it is supposed that the insects are
enabled to ascend or adhere to polished
surfaces in opposition to gravity. In other
insects elegant brush-like appendages are

INSECTS.

[ 432 ]

INSECTS.

met with in the same situation. Disks of
the same kind but larger, and peculiarly- |
arranged hairs, sometimes occur upon the !
upper joints of the tarsus (PI. 34. fig. 6, DY- ,
TISCUS ; and fig. 4 a, APIS).

The structure of the legs of insects in the j
larval state (PI. 34. figs. 32, 33) differs con-
siderably from that of the imago as de- j
scribed above.

The wings are dry, membranous, and
transparent organs, consisting of two layers,
which are confluent at the margins, and are
folds of the integument. Between them
run canals, commonly called veins, nerves,
or nervures, which are more or less numerous
and ramified ; and upon their arrangement
the distinguishing characters of the genera
&c. are sometimes founded (WiNGs). The
veins are formed by two wide horny half-
canals in the upper and under plates, of
which the wings consist. The main veins
arise from the point of attachment of the
wings to the thorax, and gradually diminish
in diameter until they reach the extremity
of the wings. The veins convey the circula-
ting liquid, and contain each a tracheal
branch, which communicates with the
tracheae of the thorax. Each nervure con-
tains a trachea ; and the blood circulates
around it. In flight they are said to be
distended and the wings kept expanded, by
air from the interior of the body. In some
kinds of wings the circulating currents are
not confined to narrow channels as in the
veins, but traverse a large part of the
breadth of the wings (COCCINELLA).

Most insects have four wings ; but in
some the males only are furnished with these
appendages. In the Diptera,the posterior pair
of wings are rudimentary, being replaced
by two little club-shaped bodies, called the
halteres, poisers, or balancers. In this order
also, and in some insects belonging to other
orders, a pair of small and rounded membra-
nous or scaly appendages are attached to
the back of the case of the first pair of
wings, called in the former the squamas
halterurn, and in others, alulae or winglets.
In some insects, as in the beetles (Coleo-
ptera), the anterior pair of wings are hard,
horny, and opaque, forming wing-covers or
ELYTRA (fig. 362), from the presence of a
horny layer ; and the lower wings, which
are usually larger, are folded together
beneath them, when at rest. In others, the
posterior wings disappear, and the elytra I
coalesce at their inner margins. Sometimes
the anterior wings are homy or leathery at '

the base, and membranous towards the
summit (fig. 363) ; these are called hem-
elytra. At others, all the wings are thin,
membranous, and transparent, as in the
Hymenvptera and Neuroptera.

In the Lepidoptera, they are covered with
beautiful feathers or SCALES.

There are also other modifications of the
wings of certain insects, adapting them for
special functions. In the Orthoptera these
modifications are the agents producing (he
well-known chirping sounds, as in the male
cricket and grasshopper. In the common
house-cricket, Acheta domestica, each of the
upper wings or elytra exhibits a clear apace
near the centre (PI. 34. fig. 10 a), traversed
by a single vein only, or at least by a very
few veins. This space has received the name
of the drum or tympanum. Bounding it ex-
ternally is a large dark longitudinal vein,
provided with three or four elevated longi-
tudinal ridges. Immediately in front of the
tympanum, near the base of the elytra, is a
transverse horny ridge, tapering outwards
and furnished with numerous short trans-
verse ridges or teeth, and forming a kind of
file or bow (PL 34. fig. 10 V). When the
two elytra are rubbed across each other, the
bow being drawn across the ridges gives
rise to the peculiar sound, the intensity of
which is increased by the tympanum acting
as a sounding-board. The apparatus of the
grasshopper is essentially of the same struc-
ture. It must be stated, however, that va-
rious other explanations of the origin of the
stridulating noise produced by these insects
have been given. Thus by some authors the
two bows are stated to work across each
other, whilst by others the legs are supposed
to act against the bow. This subject pos-
sesses interest for future observation.

In other insects, there is a peculiar mecha-
nism for uniting the anterior and posterior
wings of each side, so that they may be kept
steady and may act in unison during flight.
In the Lepidoptera, the moths only are pro-
vided with a minute hook arising from the
base of the costal nerve of the lower wing,
and inserted into a socket near the base of
the main nerve, on the underside of the
upper wing. In the Hymenoptera, there are
many such hooks arranged along part of the
costal nerve at the anterior and upper
margin of the second pair of wings (PI. 34.
fig. 13). When the wings are expanded,
these attach themselves to a little fold on
the posterior margin of the anterior wing
(fig. 11 ri), along which they play freely

INSECTS.

[ 433 ]

INSECTS.

n the wings are in motion, sliding to and
fro like the rings on the rod of a window-
curtain. These hooks are somewhat twisted
towards their free end, recurved and some-
times notched at the point. They vary in
number in different genera and even in
the sexes. In the Hemiptera the whole
margin of part of the anterior wing is hooked
over a corresponding recurved part of the
posterior, so as to produce the same effect.

The halteres of the Diptera and the elytra
of beetles present in certain parts a multi-
tude of vesicular projections of the external
membrane ; and a nervous filament passes
to each. Hicks considers them to be organs
of smelling.

The abdomen (fig. 361 ri) forms the third
and terminal portion of the body of insects.
It usually consists of nine or ten rings or
joints, the posterior of which, however, are
sometimes so concealed, so small or so fused
with the others, that they appear to be
absent. The last segment of the abdomen
of many insects in the females, is furnished
with five or six valves or setae, some of
which form stings, saws, or borers,
according to the function they perform as
weapons of defence, or to cut through the
tissues of plants or animals, so that the eggs
may be deposited in them. The saws are
well-known interesting objects. See CHAL-
CIDID^E, CYXIPID^E, and STINGS. The ab-
domen contains the principal part of the
alimentary canal and its appendages, with
the organs of reproduction.

The alimentary canal varies in length in
different insects, and even in the same insect
at various periods of its development. It
consists of the following parts : — 1. The oeso-
phagus (PI. 35. fig. 2 6), a muscular organ
extending through the thorax ; it is some-
times dilated to form a crop or ingluvies, as
in the Lepidoptera, Hymenoptera, and Di-
ptera ; and this occasionally forms a lateral
sac, connected with the oesophagus by a
narrower portion only, and called a sucking
stomach. 2. Next follows the muscular
stomach, proventriculus or gizzard (fig. 2 c),
which is distinguished by the frequently
great development of its lining membrane
into plates, teeth, or hooks of horny tissue
(PL 34. fig. 1) ; these serve to triturate the
food, and have long been known as beautiful
microscopic objects. 3. This is succeeded by
a long cylindrical true stomach or ventri-
culus (c?), in which digestion takes place.
4. Behind this is a longer or shorter small
intestine (PL 35. fig. 2, between d and /),

terminating in 5, a dilated portion, forming
a large intestine or colon ; behind which is
a short rectum. The structure and length
of the parts of the alimentary canal vary
generally according to the nature of the
food, although this is not always the case in
regard to the latter.

The alimentary canal is covered by an
outer homogeneousperitoneal layer j beneath
which is a muscular coat, consisting of lon-
gitudinal and transverse fibres. Internally
it is lined by a homogeneous epithelial layer,
consisting, in part at least, of chitine. Be-
tween the latter and the muscular coat, at
the middle of the alimentary canal, is a layer
of cells, which probably perform a glandular
function. The large intestine or colon of most
insects in the imago state contains from
four to six peculiar organs of doubtful
nature, arranged in pairs, either transversely
or longitudinally. These consist of trans-
parent rounded, oval, or elongated tubercles,
projecting inside the colon, sometimes with
a horny ring at the base, and traversed by
tufts o'f tracheae. These organs are most
numerous in the Lepidoptera. They are
never found in insects in the larva- or pupa-
state.

In most insects, salivary glands are present
as one, two, or rarely three pairs of colour-
less sacs or tubes of very variable form and
length, sometimes scarcely extending beyond
the prothorax, at others accompanying the
alimentary canal into the abdomen. They
consist of an outer homogeneous envelope,
lined with colourless nucleated cells, and
frequently have one or more distinct duct?,
sometimes containing a spiral fibre ; they
terminate near the mouth, in some insects
the ducts previously expanding into a reser-
voir.

A distinct liver is not present in insects,
its function being performed by the glandular
cells in the walls of the true stomach. In
many in&ects, caecal appendages arise from
the latter, and also contain cells which se-
crete a biliary liquid.

In some insects the small intestine is fur-
nished with glandular appendages in the
form of tubular caeca, probably representing
a pancreas.

Intimately connected with the digestive
and assimilative process is a curious organ
called the fatty body. This attains its maxi-
mum of development towards the end of the
larval period of existence. It consists of a
number of fat- cells imbedded in a reticular
or lamellar tissue (PL 35. fig. 28), composed

INSECTS.

[ 434 ]

INSECTS.

of a number of somewhat angular lobes con-
nected by narrow processes having inter-
spaces between them. These are originally
formed from rounded nucleated cells, which
have given off' anastomosing processes (fig.
29). It is traversed by a numDer of slender
tracheae, and occupies the interspaces of the
various abdominal organs. Each lobe con-
sists of an outer structureless membrane,
enclosing the fatty matter imbedded in an
amorphous or granular substance. It ap-
pears to form a reservoir of nourishment for
the insect during the pupa-state.

In most insects are found several slender
and elongated, mostly simple, tubular glands,
opening by simple or united ducts into that
end of the true stomach corresponding to
the pvlorus (PI. 35. fig. 2 e). Their free ends
are either caecal or unite with each other.
They are often very long, and much con-
voluted around the intestines, sometimes
presenting a varicose appearance, and di-
lated near their termination. These are the
Malpighian vessels j and they probably per-
form the f unction of a kidney, uric acid
having been found in them. They are
usually yellowish or brownish, and consist
of a homogeneous outer coat lined with
epithelial cells. Some authors, however,
consider that the renal organ is represented
by one or more long vessels convoluted
upon the colon and opening close to the
anus ; and we have found in the cater-
pillar of the fox moth, Lasiocampa rtibi,
numerous long convoluted tubes, of a
milk-white colour, filled with octahedra
and prisms of oxalate of lime ; these termi-
nated in the rectum close to the anus by
verv slender ducts, whilst at the upper ends,
which reached to about the anterior third
of the body, they were coiled upon them-
selves, or united with each other.

Other glandular or secreting organs also
occur in insects. Thus organs correspond-
ing to the cutaneous glands of theVertebrata
are often met with as rounded glandular
cysts diffused beneath the integument, and
called glandulae odoriferse ; they open at the
junction of the segments of the body, or at
the joints of the legs, by very short ducts,
and pour out a strongly-smelling secretion.
Spaulding describes in the mentum of the
bee, a spiral duct connected with certain
glands situated in the thorax. In other
insects, similar organs are concealed at the
posterior end of the body, and pour out
their secretion near the anus. Among the
Hymenoptera, the females are often fur-

nished with a glandular apparatus which
secretes the poison of the STING.

Spinning organs. A large number of those
insects which undergo perfect metamorpho-
sis are furnished in the larval state with
spinning organs, with the secretion of which
many larvae, before entering the pupa-state,
weave a cocoon or enclose a cavity in which
to pass their period of rest, while others use
this secretion for agglutinating foreign
bodies to serve the same purpose. The
glands secreting the silk consist of two long,
tubular caeca (PI. 34. fig. 16), which in a
more or less coiled state occupy the sides of
the body, and terminate anteriorly in two
narrow excretory ducts, dilated to form a
reservoir, and the common orifice of which
opens outside the mouth on a short tubercle
beneath the labiuni. The caterpillar is able to
compress the silken threads by the contrac-
tion of an angle formed by the two capillary
tubes at their point of union, and is thus
enabled to suspend itself by the threads.
The material of the silk is always colourless,
and derives the colour which it presents in
certain instances from a varnish secreted in
the reservoirs, and issuing along with the
former.

The heaj-t in insects exists as a long con-
tractile dorsal vessel, constricted atintervals.
This terminates posteriorly in a blind end,
and is narrower in front. The posterior
portion performs the functions of a heart,
whilst the anterior represents an aorta, and
conveys the blood from the heart to the
body. From the mouth of the aorta the
blood passes without any vascular walls, in
regular currents taking all directions, and
running into the antennae, the extremities,
the wings, and other appendages, returning
as a venous current. The blood finally
forms two principal lateral currents di-
rected towards the end of the abdomen,
and, accumulating in the neighbourhood of
the heart, is broug-ht by its diastole through
the lateral valvular tissues existing in it,
whence it is again driven through the aorta
as before. The walls of the dorsal vessel
consist of longitudinal and transverse fibres,
surrounded externally by a very delicate
peritoneal layer. The cavity of the heart is
lined by another delicate membrane, which
in the constricted parts forms internal val-
vular projections, whereby the dorsal vessel
is divided into as many chambers as there
are constrictions. Each of these cardiac
chambers is furnished at its front end, right
and left, with a fissure which can be closed

INSECTS.

[ 435 ]

INSECTS.

internally by a valvular membranous fold.
The cardiac chambers contract in regular
succession from behind forwards, and thus,
with the aid of the valvular apparatus, which
prevents the lateral exit of the blood, pro-
pel this liquid into the aorta. This is no-
thing more than a continuation of the most
anterior heart-chamber, and runs as a simple
narrow tube beneath the back of the thorax,
where it terminates either in a single aper-
ture, or divides into several short branches,
which also terminate suddenly in open ori-
fices. The number of chambers varies j but
very frequently there aie eight.

In the antennae, legs, and other appen-
dages of the body of insects, the arterial and
venous currents may be seen running toge-
ther, whilst in the wings the currents are
distinct.

Minute capillaries have been detected very
generally diffused.

The blood of insects usually consists of a
colourless liquid containing rounded or oval,
colourless, nucleated corpuscles (PL 49. fig.
33) j but sometimes it is yellowish or green-
ish, and rarely red.

The respiration of insects is effected by
means of TRACHEJS, two or more large
trunks of which usually traverse the body
longitudinally, giving off branches which run
in all directions, and communicating with
the air by numerous short tubes, connected
at or near the sides of the body with orifices
termed SPIRACLES or stigmata. Of those
insects which live in water, some have stig-
matic orifices which are brought into rela-
tion with the air at the surface of the water ,•
whilst others in the larval state respire the
air mixed with the water in which they live,
this process being facilitated by the presence
of external branchiae, or processes of the in-
tegument in the form of leaves, plates, or
hairs, through which numerous tracheae
ramify in every direction.

The nervous system of insects consists
essentially of a series of ganglia arranged in
pairs, one for each segment of the body, and
situated between the alimentary canal and
the under surface of the body. The ganglia
of each pair are mostly united with each
other, but sometimes distinct, and are con-
nected with those adjacent by longitudinal
cords. The uppermost pair of ventral ganglia
are connected oy two lateral cords surround-
ing the oesophagus with a large cephalic gan-
glion or brain. From the ganglia branches
are distributed to all parts of the body. A
sympathetic system of nerves is also present.

Want of space compels us to limit the
notice of the reproductive organs to the de-
scription of PL 34. figs. 18 & 19.

Many insects undergo complete metamor-
phosis, between the period at which they are
hatched arid that at which they attain their
full development. On first leaving the egg,
they assume a more or less worm-like form,
known as the larva, caterpillar, or maggot.
The next stage is that in which they usually
neither move nor take food, when they form
the nympha, pupa, or chrysalis. This state
is succeeded by that of the perfect insect
or imago. In other insects, however, among
the Orthoptera, Hemiptera, and Neuroptera,
the metamorphosis is incomplete, the body,
I legs, and antennae of the larva being nearly
similar in form to those of the imago, but
the wings are wanting. In some insects,
also, of the above orders, the pupa con-
tinues to be active, differing only from the
larva in itslarger size, and in having acquired
rudimentary wings (PL 35. figs. 15, 17, 21).
In some insects the only change consists
in ecdysis, without material alteration in
structure. Parthenogenesis occurs; and
some larvae reproduce.

Examination, fyc. The external parts and
organs of insects are usually examined as
opaque objects, the animals being held in
the stage-forceps. This method, however, is
often very unsatisfactory ; and the best 'is
to press them as much as possible between
two slides, without crushing, and to fasten
the slides together with india-rubber bands
or fine string, so that the parts may dry in
the compressed form. When subsequently
soaked in oil of turpentine, and mounted in
balsam, they will become much more trans-
parent and distinct. By prolonged macera-
tion in turpentine, the whole of the pigment
may be removed, which causes the structure
to be seen very distinctly. When the organs
are very hard and thick, they may be softened
by boiling water, or solution of potash,
before being pressed between the slides.

The internal organs, which are very deli-
cate, must be brought to view by dissection
under water, the insects being fixed by pins
stuck into the leaded cork (INTRODUCTION,
p. xxvii).

The smaller and more delicate insects,
aquatic larvae, &c. are best preserved in so-
lution of chloride of calcium or glycerine,
mounted in suitable glass cells.

To preserve insects for the future exami-
nation of the internal structure, they should
be kept in solution of chloride of zinc ; but

INSECTS.

[ 436 ]

INSECTS.

when very soft and fragile, they may be kept
in spirit and water.

Insects are divided into eleven orders,
thus •.—

Ord. 1. Coleoptera (Beetles). Wings four,
anterior hard, coriaceous or horny (elytra),
covering the posterior, which are mem-
branous and transversely folded ; mouth
formed for manducation, furnished with
mandibles, maxillae, and palpi, both labial

Fig. 362.

Cerambjx sedilis.
Nat. size.

Fig. 363.

and maxillary : metamorphosis complete
(fig. 362).

Ord. 2. Orthoptera (Grasshoppers, Crickets,
&c.). Wings four, the upper coriaceous,
veiny, the inferior membranous, longitu-
dinally plaited like a fan ; mouth serving
for manducation, with strong mandibles ;
maxilla) furnished with a cylindrical hel-
met ; metamorphosis incomplete.

Ord. 3. Hemiptera (Bugs, £c.). Wings
four, all membranous, or the anterior ones
coriaceous at the base, and thicker; mouth
with a jointed rostrum (labium), en-
sheathing seta3 (mandibles and maxillae) ;
palpi none ; metamorphosis with few ex-
ceptions incomplete (tig. 363).

Ord. 4. Neuroptera (Lace-wings, Dragon-
flies, &c.). Wings four, membranous, ge-
nerally pellucid, reticulated, naked, very
often equal ; mouth not suctorial, but
mostly made for manducation ; mandibles
in some obsolete ; females never furnished
with a sting, and but rarely with a
borer or exserted oviduct ; metamorpho-
sis mostly incomplete, in some complete
(%. 364).

Ord. 5. Lepidoptera (Butterflies, Moths).
Wings four, membranous, covered with
coloured scales; mouth furnished with
an involute, spiral tongue, composed of

Fig. 364.

Beduvius tuberculatus.
Nat. size.

labelluladepressa.
Natsizeu

INSECTS.

C 437 ]

INSECTS.

the elongated maxilla) ; metamorphosis
complete (fig. 305).

Fig. 3C5.

Danais Plexippe.
Nat. size.

Ord. 6. Ili/menoptera (Bees, Wasps, &c.).
Wings four, membranous, posterior ones
smaller, and with fewer veins ; maxillae
elongate, generally slender, sheathing the

Fig. 360.

Tenthredo nassata.
Magnified 2 diameters.

labium ; abdomen of the females almost
always terminated by an ovipositor or a
sting; metamorphosis complete (fig. 306).

Ord. 7. Diptera (Flies). Wings two, with
alulets at the base ; two halteres ; mouth
suctorial; labium not furnished with palpi,
prolonged into a proboscis or sheath, and
enclosing setre variable in number ; maxil-
lary palpi two, at the base of the pro-
boscis ; metamorphosis complete.

Ord. S. Htrtp*ij)iera or RJiipiptera. Males
with four wings ; anterior wings two small
moveable corpuscles; posterior wings
large, membranous, in the form of a qua-

drant of a circle, longitudinally folded like
a fan. Females apterous, vermiform,
without legs. Metamorphosis complica-
ted ; mandibles two, narrow, somewhat
curved ; palpi two, biarticulate, far apart,
inserted beneath the head (laryse, pupoe,
and females living parasitically in Ilyme-
nopterous insects).

OnL i). Suctoria or Siphonaptera (Fleas).
Wingless ; metamorphosis complete ;
mouth suctorial ; rostrum composed of two
serrated laminn and a thin suctorial seta,
included in a jointed two-valved sheath.
Ord. 10. Anoplura or Pamsitica (Lice, PI.
35. figs. 3-8). Wings absent ; not under-
going metamorphosis ; parasitic (eyes two,
simple, sometimes none).
Ord. 11. Thysanura. Wings absent ; not
undergoing metamorphosis ; not parasitic j
mouth furnished with mandibles and
maxilhe; eyes simple, in two groups;
abdomen mostly terminated by setae or a
bitid tail.

BIBL. Newport, Todd's Cycl. An. and
Phys. art. Insects ; Kirby and Spence, Intr.
Entom. ; Burmeister, JtSntom, ; Newman,
Insects] Siebold, Vergl. Anat.; Straus-
Durckheirn, Cows. gdn. s. VAnat. d. Anim.
articul. ; Westwood, Introd. ; id. Butterflies
of Great Britain ; Stephens, Brit. Beetles,
and Br. Entom. ; Spry and Shuckard, Br.
Coleopt. ; Kirby, Mon. Apum ; Curtis, Br.
Entom. ; Panzer, Deutsch. Insekt. ; Walker,
Insecta Brit. ; Fabre, Ann. Sc. Nat. se'r. 4.
vii. ; Ganin, Zeitschr. iviss. Zool. 1809 j
Kowalevsky, M6m. VAcad. St. P&ersb. xvi.
1871 ; Douglas and Scott, Hemip. Heter.,
Ray Soc. ; Schultze, Q. M. Jn. 1808 ; Lan-
dois, Sclmltze's Archiv, 1807 ; Lyonet, Ann.
Sc. Nat. se'r. 2. t. v. ; Ratzeburg, JForst-
Insekt. 1844; Lacaze-Duthiers, Ann. Sc.
Nat. s6r. 3. t. xix. ; Gerstaecker, Klass. und
Ordnung. ; Weismann, Dipter. ; Herold,
Schmetterl. ; Metschnikow, Zeit. wiss. Zool.
B. xvi. ; Leydig, Hist. ; Gegenbauer, Vergl.
Anat. 1878; Scudder, Tr. Smith. Inst.;
Hicks, J. Linn. Soc. i. ISO; id. Linn. Tr.
xxii. 141, xxiii. 189; T. West, Linn. Tr.
xxii. 393 ; Hepworth, Q. Mic. Jn. ii. 158 ;
Packard, Mem. Acad. (Pcabody) Entomol. ;
Charpentier, Orthopt. ; Fischer, OrtJiopt.
Europ. ; WoliF, Riechorg. Biene fyc. 1875 j
Watney, Jn. M. Soc. 1877, xvii. 213 ; Frey,
Lepidopt. Schweiz, 1880 ; Kb'ppen, Injurious
Insects, Russia, 1880 ; Brehm, Insect. 1881,
1500 figs. ; Newman, Br. Moths and But-
terfl. ; Wilson, Larva of Br. Lepid., figs, j
Lowne, Phil. Tr. 1878, 577, eyes; Minot,

INSILELLA.

[ 438 ]

INTESTINES.

Arch. Phys. 1876, trachea ; Adolph, Insekt-
Fluqd, 1880 ; Spaulding, Amer. Nat. 1881,
xv. '113 (Jn. M. Soc. 1881, 442); Dritl,
Zeitschr. wiss. Zool. 1876, xxvii., brain',
M'Lachlan, Enc. Brit. 1882, xiii. 141.

INSILEL'LA, Ehr.— A genus of Diato-
maceae.

Char. Frustules single, fusiform, with a
turgid ring (hoop ?) interposed between the
valves, which are equal ; = a terete Biddul-
phia. Marine.

I. africana. Frustules with four constric-
tions, broader and subglobose in the middle,
diminishing in size towards the acuminate
ends ; no markings visible by ordinary illu-
mination j length 1-530; on the coast of
Africa.

BIBL. Ehr. Ber. Berl. Ak. 1845, 357;
Kiitz. Sp. Alg. 32.

INTERCELLULAR PASSAGES, SPACES,
&c. OF PLANTS. — Where the cells of vege-
table tissue are of any but six- or twelve-
sided forms, interspaces must exist between
them. These are especially evident in pa-
renchyma formed of rounded cells, where

Fig. 368.

\l

Vertical section of half a leaf of a Potamogeton, with
air-spaces I.

Magnified 200 diameters.

there exist of course, angular intercom-
municating intercellular passages. The
stomata of LEAVES always communicate
with such intercellular passages, larger in
the lower part of the parenchyma of leaves.
Intercellular spaces are lacunae of larger
size, definite or indefinite in form, bounded
by a number of cells of less capacity than
the space itself. These are especially large
and abundant, as air-receptacles, in aquatic
plants, both in the stems and leaves, as in
the Nymphaeaceae, Naiadaceae (fig. 368),
and Hydrocharidaceae, &c., but also com-
mon in most Monocotyledono us plants, such
as Juncacese (PI. 47. fig. 18), Araceae,
Grasses, &c.

Intercellular spaces and canals likewise

serve as RECEPTACLES for SECRETIONS, as
in the case of the glands of the Aurantia-
ceae (fi£. 280) (see also GLANDS), and the
turpentine-canals of the Coniferae. The
milk-vessels of plants appear to be formed
sometimes in intercellular canals, sometimes
out of cells (LATICIFEROUS TISSUE).

BIBL. Works on Structural Botany.

INTERCELLULAR SUBSTANCE OF
PLANTS, OR SECONDARY CELL-DEPOSITS.
— When we make fine sections of many
kinds of cellular structure, as for instance
of the horny albumen of the seeds of Palms
(Areca, PL 47. fig. 21) or other plants, of
the collenchvmatous tissue beneath the epi-
dermis of the Chenopodiaceae &c., of the
substance of cartilaginous Algae, of many
woods, &c., we find an appearance of inter-
vals between the lines bounding the com-
ponent cells, which intervals are filled up
with apparently homogeneous substance.
Thus seen and no further investigated, the
interposed matter was formerly described
as intercellular substance, a peculiar form of
vegetable organization ; and some went so
far as to imagine that cells originated free
in this, and subsequently became glued to-
gether and fixed by the solidification of the
whole (Unger and Endlicher). The appli-
cation of dilute sulphuric acid to prepara-
tions of this kind, with iodine, generally
shows clearly that the supposed intercellu-
lar substance consists of secondary deposits
really inside the cells (PI. 47. fig. 22). Re-
cent observations go to prove that the
supposed intercellular substance, a matter
secreted or otherwise produced between the
cells of a tissue, is of very rare occurrence,
even if existing at all. Probably the
appearance is produced by modification of
the cell- wall. See EPIDERMIS, SECON-
DARY DEPOSITS, WOOD, and ALBUMEN.

BIBL. Mohl, the BIBL. of CELL-MEM-
BRANE ; Unger, An. u. Phys. Pfl. 1846, 18 ;
Mulder and Harting, Phys. Chem. ; Hartig,
Ann. Sc. Nat. 2 se>. v. ; Wigand, Intercell.
Subst. 1850; Cohn, Linncea, xxiii. 337,
1850 ; Schacht, Pflanzenzelle, Berlin, 1852,
76 ; Bentley, Bot. j Henfrey-Masters, Elem.
Course.

INTESTINES.— The intestines consist
of three coats: an outer, peritoneal, or
serous membrane, an inner or mucous mem-
brane, and an intermediate muscular coat.

The connective tissue of the mucous
membrane is often indistinctly fibrous,
especially its inner portions, where it forms
the basement membrane j it contains scat-

INTESTINES.

[ 439

INTESTINES.

tered, roundish, elongate nuclei, without
elastic tissue. Between the proper mucous
membrane and the submucous tissue, is
situated alayer of longitudinal and transverse
unstriped muscular fibres, frequently, how-
ever, indistinct in man.

Fig. 369.

Magnified 60 diameters.

Perpendicular section of the wall of the lower part of
the ileum of the calf: a, villi ; 6, Lieberkiihn's glands,
c, muscular layer of the mucous membrane ; d, follicle
of a Peyer's gland; e, subjacent portions of the submu-
cous tissue ; /, circular muscular fibres ; g, longitudinal
ditto.

The epithelium of the intestines consists
of a single layer of cylindrical cells, con-
taining a transparent oval nucleus, with one
or two nuclei, and granular matter.

In the small intestines, the free border of
the epithelium-cells presents a broad seam
with delicate longitudinal striae, forming
the so-called pore-canals. Besides the
ordinary cylindrical or columnar cells are
certain cup-, or goblet-shaped cells, the open
mouths of which are directed towards the
cavity of the intestine (PI. 53. fig. 20). It

is a question whether these goblet-cells are
modified epithelium-cells, or represent pe-
culiar morphological elements.

The surface of the small intestines is
covered with VILLI, which are absent in the
large intestines ; and in every villus one or
two spaces are found, constituting the origin
of the lacteals.

The elements of the muscular coat are
unstriped muscular fibres, consisting of pale,
homogeneous, fusiform, flattened cells, with
an elongated nucleus. The fibres fre-
quently present knotty expansions, and
sometimes zigzag flexuosities.

The glandular organs of the small intes-
tines consist of : — Brunner's or the racemose
glands; Lieberkiihn's follicles or the tubular
glands ; Peyer's, the aggregate or agminate
glands ; and the solitary glands or follicles.

Brunner's glands are situated in the sub-
mucous tissue of the duodenum, extending
about as far as the orifice of the choledic
duct. If a portion of the intestine be kept
stretched, or distended with air, and the
muscular coat be dissected off, they are seen
as yellowish, flattened, roundish-angular
bodies, mostly about 1-60 to 1-25" in size,
the short ducts of which pass through the
mucous membrane. They secrete an alka-
line mucous liquid.

Lieberkiihn's follicles, or the tubular
glands (fig. 370), are distributed throughout

Fig. 370.

Magnified 60 diameters.

Lieberkiihn's follicles, from the pig : a, basement
membrane and epithelium ; b, cavit

cavity.

the small intestines, extending through the
substance of the mucous membrane. They
are very numerous, straight, narrow, slightly
dilated at the ends, and rarely bifurcate.

INTESTINES.

[ 440 ]

INTESTINES.

They vary in length from 1-60 to 1-84", and
consist of a delicate basement membrane,
lined with epithelium.

Peyer's glands are rounded or elongated
flattened aggregations of glands, appearing

Fig. 371.

Magnified 10 diameters.

Portion of a Peyer's gland, human : a, follicles sur-
rounded by the orifices of Lieberkuhn's glands ; bt villi ;
c, scattered Lieberkiihn'a glands.

upon the inner side of the intestine as
slightly depressed spots. They are most
numerous in the ileum, but are sometimes
found in the lower part of the jejunum, or
even its upper part and the duodenum.
They are usually twenty, thirty, or more in
number. They vary in length from 1-25
to 1^". Each consists of an aggregation of
closed and rounded follicles, from 1-70 to

Tig. 372.

Solitary gland, covered with villi, from the jejunum.

1-12" in diameter, partly seated in the mu-
cous membrane itself, partly in the sub-
mucous tissue. The follicles are surrounded
by a ring of Lieberkuhn's glands, which,
with villi, also occupy the intervening por-
tion of the mucous membrane. Each fol-
licle consists of a tolerably firm coat of
indistinctly fibrous areolar tissue, with scat-
tered nuclei, enclosing a grey soft sub-
stance consisting of innumerable nuclei and
cells, from 1-3000 to 1-1500" in diameter,
with a few granules of fat. The follicles
are surrounded by a vascular network, which
sends off branches to their interior.

The solitary glands agree in structure
with the individual follicles of Peyer's
glands. Their free surface is usually con-
vex, and covered with villi (fig. 372).

The glandular organs of the large intes-
tines are Lieberkiihn's glands and the soli-
tary follicles.

The Lieberkuhn's glands agree in struc-
ture with those of the small intestines,
except that they are larger and broader in
proportion to the greater thickness of the
mucous membrane. The solitary follicles
also differ from those of the small intestine

Fig. 373.

Magnified 45 diameters.

Solitary follicle from the colon of a child : a, tubular
glands; b, muscular coat of the mucous membrane ; c,
submucous tissue ; d, transverse muscular fibres ; e, pe-
ritoneum ; f, depression in mucous membrane over the
follicle g.

in their larger size, and in the circumstance
that each of the minute elevations of the
mucous membrane produced by them
exhibits a rounded or elongated opening,
leading to a depression in the mucous
membrane over the follicle (fig;. 373). This,
however, has no communication with the
follicle.

The investigation of the structure of the
intestines is a matter of some difficulty.
The epithelium must be examined in a
perfectly fresh state. The glands are
most readily seen in portions hardened by
absolute alcohol or chromic acid; whilst
some have recommended boiling with acetic
acid (80 per cent.), then drying and making
sections with a Valentin's knife. The
muscular elements are rendered most di-
stinct by maceration with dilute nitric acid
(20 per cent.).

INULINE.

[ 441 ]

IS ARIA.

The capillaries of the intestines are very
beautiful when injected ; but great care is
required in securing the vascular branches,
to prevent the escape of the injection.

Two thick layers of ganglionic nervous
masses are distinguishable in the intestines.
One is situated in the submucous tissue, the
other between the circular and longitudinal
muscular fibres. The former is a flat layer
with a few ganglia projecting towards the
mucous membrane and penetrating among
the follicles; the latter is more irregular,
and presents nodulated ganglionic masses.
The ganglia give off and are traversed by
nerves that form a plexus, some joining the
ganglionic layers, others uniting with the
mesenteric nerves. The nerves are non-
nieclullated.

BIBL. Kolliker, Mikr. Anat. ; Verson,
Strieker's Hist.; Frey, Hist., $ the full
literature.

IN'ULINE.— A substance allied to
starch, occurring in solution in the cell-
contents of plants, especially the Compo-
sites, as the Dahlia, dandelion, &c. ; it is
coloured yellow by iodine. It forms crys-
talloids or spheerocrystals resembling those
in PI. 39. fig. 11 ; and they exhibit the
black cross with polarized 'light. In a
section of a tuber of the Jerusalem arti-
choke, macerated in spirit, they will be
found in the cells, and may be mounted in
glycerine.

BIBL. Gmelin, Chemie, vii.; Prantl, Inulin^
1870; Dragendorff; Material. $c., 1870;
Sachs, Sot. 1874.

IODINE.— Solution of iodine is often
useful for dyeing and rendering very trans-
parent objects more distinct, and for its
producing with some vegetable and animal
tissues and substances colours by which
they may be distinguished. The general
results of its action are enumerated in the
INTRODUCTION; and special remarks are
made under the heads of the tissues.

An aqueous solution of iodine is the best
for general use ; but a solution in spirit is
much stronger. A very strong solution may
be made by dissolving iodine in a solution
of iodide of potassium ; this may be used
for dyeing tissues, but not for the detection
of cellulose, as the precipitated iodine gives
a bluish tinge to the structure. Solutions
of iodine in chloride of zinc, and of iodide
of zinc are valuable reagents for cellulose.
See SCHULTZE'S TEST.

Iodized serum is made of amniotic fluid
(calf) and a small quantity of strong tincture

of iodine. It has a pale yellow tint. It is
used as but little altering the appearances
of delicate objects.

An artificial substitute may be made
with 1 oz. of white of egg, 30 grs. of salt,
8 oz. of water, enough tincture of iodine to
colour, and 2 or 3 drops of carbolic acid, the
whole to be well shaken and filtered.

IRID^E'A, Bory.— A genus of Cryptone-
miacese (Florideous Algee), containing one
common British species, /. edulis, a dull-red,
obovate, leaf-shaped sea- weed of fleshy-car-
tilaginous texture, 4-18" long, the central
substance composed of longitudinal, the
cortical of closely-packed moniliform per-
pendicular filaments. Fructification : spores
in spherical masses (favellidia), imbedded in
the frond in wide patches near the extre-
mity ; tetraspores in dense band-like im-
mersed sori.

BIBL. Harvey, Mar. Alg. 150, pi. 19 A ;
Phyc. Brit. pi. 97; Greville, Alg. Brit.
pi. 17; Eng. Sot. pi. 1307.

IRIDESCENCE. See INTRODUCTION,
p. xxxv.

IRIS. See EYE, p. 311.

ISARIA, Hill. — A genus of ISARIACEI
(reputed Hyphomycetous Fungi), growing
upon dead insects, fungi, or twigs or leaves
of plants. I. farinosa, Fries, grows to a
height of 1-2" on dead pupae, spiders' nests,
&c. /. arachnophila, Ditton, intricata, Fr.,
puberula, Berk., and Friesii, Montague, are
also British. I. citrina (tigs. 374, 375) is a

Fig. 374.

Isaria citrina. Plants on a fungus. Natural size.

small species, growing gregariously on ve-
getable substances.

Tulasne has recently published an inter-
esting paper on Isaria, showing that at any
rate some of the forms referred to this genus

are conidiiferous fruits of certain SphceritB

in particular that Is. crassa (farinosa, Fr.)
is a form of Sphceria militaris. This plant is
found most frequently on the larvae of Bom-
byx RuU] and the first sign of its growth is
the formation of a mildew, between the
rings of the abdomen, very much resembling
a Botrytis. Subsequently the body of the
larva, quite filled up and rigid with mycelial

ISARIACEI.

[ 442 ]

ISOETES.

growth, bears the claviform receptacles of
Isaria ; and at a still later period, some of
the larvae bear the claviform receptacles and

Fig. 375.

Isaria citrina. A single plant, showing the fruit.
Magn. 20 diams.

the conceptacles, containing asci, ofSpharia
militaris. The spores (or conidia) of the
Botrytis-form and of the Isaria-foim are
capable of germination.

BIBL. Berk. Hook. Br. Fl. vi. pt. 2. 464 ;
Ann. N. ft. i. 259, vi/132, pi. 12. fig. 12,
1850, v. 464; Fries, Summa Veget. 464;
Montagne, Ann. Sc. Nat. 2 s6r. v. pi. 12.
fig. 3 ; Tulasne, Ann. Sc. Nat. 4 ser. viii. 35.

ISARIA'CEI.— A family of Hyphomyce-
tous Fungi, growing on decaying animal
substances or larger Fungi, characterized
by a cellular receptacle formed of fila-
ments approximated together and conjoined
throughout their whole length, each fila-
ment terminating in a spore. Recent ob-
servations throw doubt on the independ-
ence of this family, which perhaps consists
simply of conidiiferous forms of other genera.

British Genera.

Isaria. Receptacle clavately branched,
formed of densely interwoven coalescent fila-
ments, or cellularly fleshy. Spores borne on
simple sporophores arising on all sides.

Anthina. Receptacle clavately branched,
formed of parallel filaments, loosely inter-
woven or free, feathery or villous at the
summit only, where they form the simple
sporophores.

Ceratium. Receptacle somewhat horn-
shaped, of a ' mucilaginous consistence,
sprinkled with filaments which are sur-
mounted by naked spores.

I'SIAS. — A genus of Copepodous Ento-
mostraca. /. davipes, in British seas.
(Brady, Copepoda, Hay Soc. i. 62.)

ISINGLASS.— This material consists of
finely-divided shreads of the swimming-
bladder of species of Sturgeon, and con-
sequently exhibits structure under the mi-
croscope, consisting of a fibrous tissue with
here and there fragments of blood-vessels
&c. It is sophisticated with cut gelatine,
which is structureless and moreover becomes
more* translucent when soaked in water,
while isinglass becomes opaque and white.
BIBL. Hassall, Adulterations, 309.
ISOCHILI'NA, Jones.— An oblong equi-
valved Ostracode, belonging to the Leperdi-
tiadce, and found only in the Silurian rocks
of Canada, Russia, and Bohemia.

BIBL. R. Jones, Ann. N. H. 3. i. 248 ;
Schmidt, Mem. Acad. St. Petersb. xxi. 2.

ISOETES.— A genus of Psilotese (Lyco-
podiacese). I. lacustris, Quill wort, the only
British species, occurs in mountain-lakes.
Isoetes is very remarkable in its mode of
growth.

The woody substance of the stem, like
that of the Lycopodiacese generally, is a
solid central body, without a pith ; it is
surrounded by a thick pareuchymatous
rind, which makes up the greater part of
the mass of the corm ; the woody mass itself
is cylindrical above, and somewhat hemi-
spherical below, the convexity downward,
and it has a layer of cambium not only over
the growing apex, but over the convexity
of the sides and lower surface. Every year
a new portion of wood is added to the
upper end, and also to the outer angle of
the convex lower mass. The roots are pro-
duced in cycles of tens, sometimes one,
sometimes two in a year ; in each cycle the
oldest root is the inmost ; but the succeed-
ing cycles appear in the middle of their
predecessors, and push them out, and up to
the side. The rind is renewed every year
by the cambium layer j and the latter, in its
growth to increase the size of the corm, by
degrees covers up and encloses the remains
of the earlier roots (as the woody layers
of Dicotyledonous trees overgrow broken
branches, bury them, and convert them
into imbedded knots). The leaves are of
delicate organization, and contain four lon-
gitudinal air-canals, with septa at intervals,
and one vascular bundle; they are expanded
at the base, and contain the immersed spo-
ranges. DeCandolle says the epidermis has
stomata. The sporanges are of two kinds,
or rather bear two kinds of spores ; and
there appears to be a periodicity in their
development. The fronds of I. lucustris are

1SOETES.

[ 443 ]

ISOETES.

discoverable in the interior of the bud
twelve months before they became fully
developed ; the sterile originate in spring
and the earlier part of the summer, the
fertile in the autumn, while stunted fertile
leaves appear even in the winter. If a
vigorous leafy plant be examined, it will be

Fig. 376.

Isoetes setacea.
Natural size.

found to have a few sterile leaves outside,
then a circle of leaves with oosporanges,
next a circle of anthero-sporanges, and in
the centre of the bud sterile leaves closing
the annual cycle. The sporanges are some-
what plano-convex longish-oval cases, with
transverse processes forming imperfect septa,
dividing them into several chambers (fig.
378). The cases are sheathed by a mem-
branous expansion of the base of the leaf
(fig. 377), to which they are adherent by
the back (fig. 378) ; the septa arise
opposite the point of attachment at the
back, and, spreading out, join the front wall.
The different contents of the sporanges are
evident before they open, those with the
small spores (antherosporanges} having a
smooth face, those with large spores (oospo-

ranges) being rendered tubercular from the
protrusion of the wall by the underlying
bodies. The wall of the capsule is mem-
branous and has no regular dehiscence, the

Fig. 377. Fig. 378.

Fig. 379.

Isoetes setacea.

Fig. 377. Base of a detached fertile leaf, seen in face.
Magn. 5 diams.

Fig. 378. Vertical section, from back to front of ditto.
Magn. 10 diams.

Fig. 379. Horizontal section, oosporange with macro-
spores. Magn. 10 diams.

spores escaping by decay of the membrane
in front.

The smaller scores resemble pollen-grains;
they are usually of the shape of quarters of
a globe, more rarely tetrahedral, with an
outer coat presenting ridges at the angles,
and an inner which is a rounded sac. The
outer coat is finely dotted in I. lacustris.
The large spores are at first of a tetrahedral
form with rounded angles, but when ripe
they become globular. The delicate inmost
layer is enclosed in a thick exospore com-
posed of three layers: — the innermost of mo-
derate thickness, brown colour, and glassy
consistence, exhibiting striae and three
strong ridges converging to a point at the
angle where the spore meets its three sister
spores ; the next coat is thinnish, and of
granular character and yellow colour ; the
outermost is a clear and gelatinous layer :
the outer two follow all the markings of
the glassy coat, and are especially thick
over the three ridges.

ISOETES.

[ 444 ]

IXOPES.

The contents of the microspores are at
first merely granular protoplasm. About a
month after they are scattered from the
sporange, the protoplasm of the cell becomes
divided into two or four portions, which
form cells, in each of which again are de-
veloped two vesicles, each producing a fila-
ment coiled up spirally. The spores swell,
the daughter cells burst, and the lenticular
vesicles escape ; the latter then open and
emit the spiral filaments, which are found
to be covered with cilia on the anterior
turns of the spiral, by means of which they
move actively through the water. They are
the spermatozoids.

The macrospores when they escape from
the sporange, contain only protoplasm with
oil-globules. In the course of a few weeks,
the internal cavity of the spore begins to
exhibit a development of cellular tissue, by
which it is subsequently filled up ; this is
the pro/thallium. At the same time, the in-
ternal coat increases in thickness, and ex-
hibits several layers. The increase in size
of the prothalliimi causes the spore-coat to
burst at the apex where the three ridges
meet, so that three triangular valves turn
back, exposing the prothallium. On this
are developed the archegonia, the first on
the apex in the central point where the
three points of the spore-coat meet. If this
is not fertilized, others are produced around
it. The archeyonium is of much the same
character essentially, as that of the rest of
the higher Cryptogamous Plants, consisting
of a papilla with a central canal leading to
the embryo-sac. The four rows of cells
forming the neck of the archegone separate,
and a germ-cell is formed in the embryo-
sac. This is fertilized by the entrance of a
spermatozoid into the embryo-sac.

In the development of the embryo in the
spore, it forms a cellular body, which gra-
dually displaces the cellular tissue originally
filling this up. The first leaf and roots are
developed while the rudiment is still within
the spore-coat, in opposite directions, and
horizontally (right and left) in relation to
the apex of the spore. The young plant
somewhat resembles a germinating Mono-
cotyledon.

The woody structure of the stem of Isoetes
consists of spiral-fibrous cells, usually annular
or retipuluted, but sometimes really spiral.

Carruthers has explained the resemblance
of the method of the growth of Isoetes and
that of the gigantic Lepidodendron of the
Carboniferous deposits.

BIBL. Bischoff, Crypt. Gewdch. Rhizoc.,
Nuremberg, 1828,70; Mohl, Verm. Schrift.,
Tubingen, 1845, 122 ; Miiller, Sot. Zeit. vi.
297, 1848 (Ann. N. H. 2 ser. ii. 81);
Mettenius, Btitr. z. Bot. Heidelberg, 1850 j
Hofmeister,^tM. sacks. Ges. d. Wiss.iv. 123 ;
Braun, Flora, 1847, 33; Carruthers, Lect.
Roy. Inst. 1869 ; Henfrey-Masters, J?(^. 1878.

ISOT'RICHA, Hein.— A genus of Holo-
trichous Infusoria =Opalince with a ventral
mouth. In the rumen of ruminants.
(Kent, Inf. 497.)

ISTH'MIA, Ag.— A genus of Diato-
maceae, fam. Biddulphiaceae.

Char. Frustules depressed or subcylindri-
cal, rhomboidal or trapezoidal in front view,
angles more or less produced ; frustules co-
herent by the angles, basal frustule stipitate ;
surface of valves and hoop appearing reticu-
lar or cellular. Marine. Two British species.

The depressions upon the valves and
hoop are so large as to produce a distinct
reticular or cellular appearance when viewed
by ordinary illumination.

/. obliquata (nervosa, K.). V. with linear
thickenings, giving them a coarsely reticular
or veined appearance.

I.enervis (PI. 17. fig. 2). Valves uniformly
covered with depressions.

BIBL. Ehr. Inf. 209 ; Kiitz. Bacitt. 137,
and Sp. Alg. 135 ; Ralfs, Ann. N. H. 1843,
xii. 270 ; Rabenh. Alg. i. 309.

ITCH-INSECT. See SARCOPTES.

IVORY. — This substance, which consists
of the tusks of the elephant, possesses the
minute structure of the ivory of teeth.

IVORY, VEGETABLE. — This substance,
consisting of the ALBUMEN of the seeds of
a Monocotyledonous tree, Phytelephas ma-
crocarpa, is composed of cellular tissue, with
the walls so thickened by horny secondary
deposits that the cavities of the cells are
almost obliterated. The pores of the se-
condary deposits, however, remain unco-
vered throughout all the thickening, and
thus are converted into tubes or canals run-
ning to meet each other from the small re-
maining cavities of contiguous cells. In
PI. 47, fig. 23 b represents a section mounted
in Canada balsam, which has in part pene-
trated into the cavities ; the remaining ca-
vities and pore-canals are filled with air and
thus appear black (a).

IXO'DEA. — A family of Arachnida, of
the order Acarina.

Contains the genera IXODES and ARGAS.

IXO'DES, Latr.— A genus of Arachnida,
of the order Acarina, and family Ixodea.

JAMESONIA.

[ 445 ]

Char. Palpi canaliculate, sheathing the
rostrum; mandibles three -jointed, basal
joint internal, the second joint external and I
long, the third short, denticulate ; labium
covered with reflexed teeth ; body very ex-
tensile, furnished near the rostrum with a
dorsal horny shield; legs with two claws
and a caruncle.

These animals form part of those which
are popularly known as ticks. They are com-
monly found in dense woods, upon brush-
wood, briers, &c., from which they get upon
animals, as dogs, oxen, horses, &c., burying
the rostrum deeply in the skin and sucking
the blood, so as to become distended to ten
times their original size. They are also
found upon reptiles, birds, and occasionally
attack man.

Haller points out two foramina at the
hinder margin of the last joint of the first
pair of legs, covered with a membrane, and
with otoliths, forming an auditory apparatus.

The species are very numerous, and have
been arranged in several genera by some
authors. The following are the commonest
species : —

I. ricinus, the dog-tick. Body oval, in
the gorged condition becoming globular and
blackish violet ; legs and appendages brown.

I. reduvhis. Pale yellowish red; head
and legs black. Found upon sheep.

1. pictus. Back white, with brown
spots; crenulate posteriorly; legs brown.
Found upon deer ; also upon mosses.

I.Ijvgesii (pfofnfetttyDug.) (PI. 6. figs. 19-
22). Oval, leaden grey, without spots.
Found upon dogs.

I. plumbeus, Leach. Shield heart-shaped,
slightly rugose ; rostrum, palpi, and legs
pale ferruginous ; body of a leaden colour ;
lenglh 1-4". Found upon and in the nests
of the bank-swallow (Hirundo riparia).

BIBL. Gervais, Walck. Apter es, iii. 234 ;
Hermann, Mem- Apter. ; Duges, Ann. Sc.
Nat. 2 ser. ii. ; Leach, Linn. Tr. xi. ; Koch,
Uebers. ; Denny, Ann. N. H. 1843, xii. ;
Gene, ibid. 1846, xviii. 160; Macalister,
Qu. M. J. 1871, 166 ; Murray, .Ec. Entom. ;
Megnin, 121 ; Haller, Zool Anz. 1881, 165
(Jn. Mic. Soc. 1881, 449).

J.

JAMESO'NIA, Hk.— A genus of Gram-
mitideae (Polypodiaceous Ferns). Cne
species ; Andes. (Hooker, Syn. Fil. 369.)

JA'NIA, Lamouroux. — A genus of Coral-
linaceae (Florideous Algae), calcareous fila-
mentous bodies, occurring in tufts, pale red j

or purplish when fresh, on small Alga3 be-
tween tide-marks. The filaments are arti-
culated, dichotomously branched, and im-
pregnated with a calcareous deposit. The
fruit consists of urn-shaped ceramidia,
formed out of the end joints of the branches,
a dichotomous continuation of which is re-
presented by a pair of minute divergent
horns on the ceramidium ; the latter has a
pore at the apex, and contains a tuft of erect
linear tetraspores. British species :

J. rubens. Joints of principal branches
cylindrical. Harvey, Phyc. Brit. pi. 252.

J. corniculata. Joints of principal branches
obconical and compressed, /. c. pi. 234.

BIBL. Harvey, /. c.. and Mar. Ala. 107.
pi. 13 D.

JAT'ROPHA. See CASSAVA.

JONESIA, G. S. Brady, 1865.— A
marine Ostracode. See BYTHOCYTHERE.

JONESIEL'LA, Brady.— A genus of
Copepodous Entomostraca.

Two British species; in dredgings.
(Brady, Copep., Ray Soc. ii. 38.)

JULTJS, Linn. — A genus of Chilopodous
Myriapoda. J. terrestris and a few other
species are often found in gardens.

JUNGERMANNIA, Dill.— A genus of
Jungermanniese (Hepaticas). Fructification
terminal. Perichastial leases free or united
only at the base, like or unlike the stem-
leaves. Perigone membranous, tubular,
plaited-denticulate at the apex, the mouth
three- or six-cleft. Vaginule membranous,
included or rarely exserted. Capsule four-
valved, splitting to the base. Amphigastria
present or absent.

This is the largest genus of the Junger-
mannieae ; among the commonest species
are J. bicuspidata, L., J. albicans, L., J. bar-
bata, J. setacea, &c., found on wet bogs,
banks, rocks, &c.

BIBL. Hooker, Br. Jungerm.) Br. Flo?\
i. pt. 1. 112, &c. ; Ekart, Synops. Jungerm. ;
Nees v. Esenbeck, Europ. Lebermoose ;
Gottsche, Lindenberg, and Nees, Synops.
Hepatic., Hamburg, 1844-47 ; Stephani,
Jungerm. (Germ.) 1879.

JUNGERMANNTEJE.— A family of
Henaticse, distinguished by possessing a
distinct stem, bearing leaves, often with
stipule-like bodies called amphigastria (fig.
380), with terminal archegones, and spo-
ranges bursting by four valves (figs. 320
and 321), destitute of a columella, contain-
ing elaters mixed with the spores.

The British genera may be grouped as
follows : —

JUNIPERUS.

Fig. 380.

[ 446 ]

Jungermannia albicans.

Stem with succubous leaves and amphigaatria, and a
lateral unopened perigone.

Magnified 10 diameters.

1. Leaves incubous (their bases covered by

the tips of those below).

* Leaves complicate; two-lobed.

t Amphigastria present: Lejeunia,

Phragmicoma, Fruttania, Madotheca,

Ptilidium.

tt Amphigastria absent. Radula.
** Leaves not complicate, two-lobed.
f Amphigastria present : Trochocolea,

Sendtnera, Schisma, Herpetium, Caly-

pogeia.
tt Amphigastria wanting. Physiotium.

2. Leaves succubous (the bases covering

the tips of those below).

* Amphigastria present: Saccogyna,
Cheiloscyphus, Lophocolea, Sphagnocw-
tis, Jungermannia, Allieularia.

** Amphigastria absent: Playiochila,
Sarcoscyphus, Gymnomitrium, Haplomi-
trium. See the genera.

JUNIP'ERUS, L.— A genus of CONI-
FERS, presenting some interesting charac-
ters in the WOOD, the POLLEN, and the
development of the OVULES.

JUTE. — The liber of Corchorus capsularis,
Willdenow, an East-Indian plant belonging
to the family of the Tiliaceae, so many of
which furnish fibrous substances, such as
the bast used for matting, which is the liber
of, the lime-tree. Jute has a very long,
glossy fibre, and is very largely imported
into this country. PI. 28. fig. 3 represents
the single liber-fibres (see FIBROUS STRUC-
TURES and LIBER).

BIBL. Hooker, Jn. Bot. i. 25, 1849.

KIDNEY.
K.

KALLYME'NIA, J. Ag.— A genus of
Cryptonemiaceee (Florideous Algae), fleshy
membranous sea-weeds of red colour, with
ribless leaf-like fronds, having three strata
of cellular tissue — the central filamentous,
the intermediate of large round cells, the
cortical of minute cells in vertical rows.
Fructification : spherical masses (favellidid)
of spores half immersed in the frond, and
tetraspores, which are tetrahedrally subdi-
vided, and occur scattered. The two British
species, K. reniformis and Dubyi, are both
rather rare.

BIBL. Harvey, Mar. Alg. 150, pi. 19 B ;
Phyc. Brit. pi. 13. 123 ; Engl Bot. pi. 2116.

KAULFUSSIA, Blume.- Fi 3gl
A genus of Marattiaceous
Ferns, with curious roundish
sori, formed of radiately co-
herent sporanges, opening by
a slit at the top (fig. 381).
1 spec., Assam (Hooker, Syn. A sorus.

444) . Magn.25 diams.

KERO'NA, Miill., Ehr.— A genus of In-
fusoria, of the family Oxytrichina.

Char. Body covered with cilia, hooks also
present, but no styles.

K. polyporum, = Stylonichia polyporum
(PI. 50. fig. 13). Body whitish, depressed,
elliptico-reniform, with a row of longer cilia
in front below the mouth ; length 1-144".
Parasitic upon Hydra.

BIBL. Ehr. Inf. 368; Duj. Inf. 422;
Claparede et Lachm. In/us. 69, 161.

KERO'NIA.— A family of Infusoria
(Duj.), nearly corresponding to the Oxy-
trichina of Ehr.

Dujardin's family comprises Halteria,
Oxytricha, and Kerona.

KIDNEY.— The kidney consists of its
enveloping membrane and the secreting
parenchyma.

The membrane is a firm fibrous coat,
called the capsule. It is composed of con-
densed connective tissue, and is continuous
with that constituting the matrix of the
kidney, in the meshes of which are the
uriniferous tubes and blood-vessels. At
the notch of the kidney, or the hilum, this
fibrous capsule is continuous with the outer
coat of the pelvis of the kidney, and also
with the sheaths of the blood-vessels.

The parenchyma, in a transverse section,
appears to the naked eye to consist of two
parts — the inner or medullary substance, and
the outer or cortical. The medullary sub-
stance is composed of 8-15 isolated conical

KIDNEY.

[ 447 ]

KIDNEY.

masses or pyramids, converging towards the
hilum, and their apices forming the papillae ;
whilst the cortical substance constitutes the
outer part of the organ, and fills up the in-
terstices between the pyramids. Micro-
scopically examined, the cortical part also
becomes resolved into as many segments as
there are pyramids ; hence the kidneys may
be regarded as composed of a certain number
of intimately connected lobules.

Both the cortical and the tubular substance
consist principally of the urinary tubules.
These commence in each segment or lobule
by very numerous orifices on the surface of
the papilla?, and pass through the pyramids,

Fig. 382.

finally becoming again tortuous and enlarged
before terminating in the Malpighian cap-
sules.

Fig. 383.

Papilla of the kidney of a pig with the tubules in-
ected, showing their origins upon the surface.
Magnified 10 diameters.

running straight and nearly parallel with
each other (fig. 383 k). During this course
they undergo repeated dichotomous subdi-
vision (fig. 383 /), the branches being given
off at a very acute angle, and at first with
considerable diminution in size ; and some-
times they divide into threeorfourbrancb.es,
so that ultimately a larger bundle of tubes
proceeds from them, producing the increased
breadth of the pyramids towards the exte-
rior. Towards the base of the pyramids,
the parallel tubules become more loosely
connected by the interposition of bundles
of arteries and veins (which run straight),
and they diverge in all directions, pursuing
an undulating course.

On reaching the cortex, the tubules
branch off and increase in diameter, becom-
ing also very tortuous ; then they turn back,
diminishing in breadth, and run parallel
with their first course, but in the opposite
direction. They then form a curve, the
loop of Henle, and run upwards again,

Perpendicular section of the injected kidney of a rab-
bit through part of a pyramid. On the left the course
of the vessels, on the right that of the tubules is shown.
a, interlobular arteries, with their Malpighian tufts b,
and vasa efferentia c ; d, capillaries of the cortical por-
tion ; e, vasa efferentia of the outermost tufts, passing to
the surface of the kidney ; f, vasa efferentia of the in-
nermost tufts, running into the straight arteries, a, g, g ;
h, capillaries of the pyramids, arising from the latter ;
i, a straight vein commencing at the papilla ; k, origin
of a urinary tubule at a papilla ; I, o, branches of the
same ; m, coiled portion in the cortex ; n, the same at
the surface of the kidney; p, connexion with the Mal-
pighian capsules.

Magnified 30 diameters.

The urinary tubules are cylindrical, and
usually consist of a basement membrane

KIDNEY.

[ 448 ]

KIDNEY.

(fig. 384 b) lined with pavement epithelium,
d. The basement membrane is very trans-
parent, but firm and elastic. AVithin it is a
single layer of nucleated polygonal epithelial
cells (fig. 384 d, e). These, when immersed
in water, lose their polygonal form, become
rounded, and appear to fill up the tubules
entirely ; they often also burst; and then
the tubules appear to contain nothing more
than a finely granular mass with nuclei.
These changes are found to have taken place

1. A Malpighian body A, with the urinary tubule B C,
human, a, Capsule of the Malpighian body, continuous
with 6, the basement membrane of the tubule ; c, epi-
thelium of the Malpighian body; d, that of the tubule ;
e, detached epithelial cells ; f, afferent vessel ; g, effe-
rent vessel; h, Malpighian tuft. 2. Three epithelial
cc41s from coiled tubules, one of them containing glo-
bules of fat.

Magnified 300 diameters.

spontaneously if the kidney is not fresh.
But the structure of the tubules varies.
Thus, in some parts of the convoluted
tubules, the nuclei appear imbedded in a
pulpy mass or a granular epithelium ; while
in others, clear epithelial cells exist, and
are larger than in the straight tubules. In
the tuouli of the medullary portion, the
epithelium is columnar; and in the tubuli of
the papillae the basement membrane is
absent.

The Malpighian bodies may be regarded
as terminal dilatations of the tubules, each
containing a round plexus of vessels, form--
ing the Malpighian tuft.

The basement membrane surrounding the
tuft (fig. 384 a) is somewhat thicker than
elsewhere ; and the epithelium lining it is
continued over the free surface of the tuft ; but
this is denied by Bowman. The Malpighian
tufts consist of close convolutions of fine
vessels derived from branches of the renal
artery. The latter enter the kidney between
the pyramids, and continue to divide until
arriving at the cortical substance, where
they give off a number of long branches,
mostly running towards the convex surface
of the kidney, between the lobules, hence
called interlobular arteries. From these,
short (mostly lateral) branches are given
off, each of which terminates in a Malpighian
tuft, forming its afferent vessel. Each
afferent vessel, on entering the Malpighian
body, divides into 5-8 branches, each of

fig. 38o.

From a human kidney, a, end of an interlobular
artery ; 6, afferent vessels ; c, naked Malpighian tuft ;
d, efferent vessels ; e, tufts enclosed in their capsules ;
/, urinary tubules arising from them.

Magnified 45 diameters.

which becomes subdivided into a tuft of
capillaries; these are variously convoluted
and interwoven, ultimately uniting in a
single vessel, the efferent vessel. The afferent
and efferent vessels are usually situated near
each other, and opposite the origin of the
urinary tubule.

KIDNEY.

[ 449 ]

KIDNEY.

The efferent vessels, which, although
arising from the capillaries of the Malpi-
ghian tufts, are rather small arteries than
veins, in import and partly in structure,
terminate in the capillary network situated
in the cortical substance and the pyramids.
This network closely surrounds the coiled
tubules on all sides, and forms a connected
plexus throughout the kidney, the meshes
of which are roundish-angular ; but near
the pyramids the afferent vessels are larger,
and differ from the rest in their straighter
course and more sparing ramification.

The veins of the kidney commence on
the surface of the organ and at the apices
of the papillae by small branches connected
with the plexus ; these by their union form
larger ones, which accompany the larger
arteries.

Bowman compares the solitary efferent
vessels of the Malpighian bodies to the portal
system of the liver, both serving to convey
blood between twc capillary systems ; and
so these efferent vessels collectively form
the portal system of the kidney.

The interstices between the vessels, nerves,
and tubules of the kidney are occupied by a
stroma of connective tissue (fig. 386 c), con-
Fig. 386,

Transverse section of the cortical urinary tubules;
human, a, divided tubules, with the epithelium re-
moved ; 6, the same, containing the epithelium ; c,
stroma of connective tissue ; d, space corresponding to
a ilalpighian body.

Magnified 250 diameters.

taining elongated nuclei, and which is much
more abundant in the medullary than in the
cortical portion. At the surface this fre-
quently becomes condensed to form a very
distinct membrane, but loosely adherent to

the fibrous capsule, and which is connected
by numerous delicate processes with the
inner stroma.

The pelvis of the kidney with the calyces
and the ureter consist of an outer fibrous, a
muscular, and a mucous coat. The fibrous
coat is composed of ordinary connective
tissue, mixed with elastic tissue.

The mucous coat is thin, and not fur-
nished with glands or papillae. Its epithe-
lium (fig. 387 B) is laminated, and remark-

Epithelium of the pelvis of the kidney ; human.

A. Isolated cells: a, small, 6, large pavement-epithe-
lial cells ; c, the same containing the granules ; d, cy-
lindrical and conical cells from the deeper-layers ; e,
intermediate forms. B. Cells in sUu.

Magnified 350 diameters.

able for the variable form and size of its
elements (fig. 387 A), the deeper cells being
roundish and small, those in the middle
cylindrical or conical, and the uppermost
roundish, polygonal, and somewhat flat-
tened. The cells frequently contain two
nuclei, and bright rounded granules with
dark margins.

Lymphatics accompany the blood-vessels
at the hilum, and pass between the groups
of tortuous tubules in the cortex ; and the
nerves penetrate the kidney with the ves-
sels, and present ganglia in their course.

In the Mammalia generally the structure
of the kidneys agrees essentially with that
of man.

In the lower Vertebrata they exhibit

KIDNEY.

[ 450 ]

K1RKBYA.

differences, which relate principally to the
following particulars : — 1, the form, which
in birds, fishes, and reptiles is considerably
more elongated, and frequently flattened ;
2, the tabulation, which in the human adult
kidney is indistinct, although marked in
the foetus, whilst in that of other Vertebrate
the separate lobules are very distinct, some-
times being connected only by the branches
of the ureter ; 3, the Malpighian tufts, which
in birds, reptiles, and fishes consist of a
single convoluted vessel, and which in some
(naked reptiles) are larger, in others (osseous
fishes) smaller than in man, whilst in birds
(also the sheep) they have been found
inserted into the sides of the tubules ; and
4, in the structure and arrangement of the
urinary tubules : these are uniform in size
in fishes, furnished with ciliated epithelium
in the reptiles and fishes, Ttnd present varie-
ties in regard to the convolution, branching,
and termination in the ureter.

Renal organs have been noticed in the
Mollusca, Arachnida, and Insecta.

The epithelial cells of the urinary tubules
are not unfrequently found to contain the
ordinary urinary deposits, which are more
often still met with in the cavities of the
tubules. Many of these are probably, how-
ever, formed after death (see URINARY
DEPOSITS).

Among the morbid changes of the kidney,
passing over cancer, tubercle, variations in
the degree of vascularity, the presence of
calculi" and the ordinary products of inflam-
mation, may be mentioned the occurrence
of cysts. 'These are met with of various
size and in variable number. The walls
of the cysts do not differ in structure from
those of'the tubules, except in being thick-
ened; they have been accounted for as
arising from dilatation of the tubules or
Malpighian capsules, in consequence of
obstruction to the escape of the urine,
distention of the epithelial cells of the
tubules, and degeneration of their nuclei,
forming colloid cells. The first is probably
the general cause, and certainly an occa-
sional one, the Malpighian tufts having
been found within the enlarged cysts after
injection. Sometimes the cysts are those of
jEchinococci. In Bright's kidney the tubules
are found deprived of their epithelium,
the cells filled with albuminous, fibrinous,
or fatty matter, and the fibrous tissue
increased, — in the advanced stage both
becoming un distinguishable in some parts,
whilst in others the cells and tubules are

loaded with fatty globules, producing the
well-known granular appearance. And in
certain cases, the kidneys become "waxy,"
the Malpighian corpuscles and intertubular
spaces, sometimes the tubules also, being
filled with amylaceous corpuscles.

In examining the structure of the kidney,
sections must be made with a Valentin's
knife. The arrangement of the vessels may
be shown by injection; and the injected
preparations are very beautiful, and form
general favourites. The Malpighian bodies
are readily filled, the injection being thrown
into the artery ; and they are easily recog-
nized by their resemblance to little apples
upon the branches of a tree (PI. 39. fig. 35).
The injection should be red. If the injec-
tion be coarse, it will burst through the
capillaries of the tufts, and partly till the
tubules as in fig. 383 p ; but if it be fine,
it will fill the venous plexus. The urinary
tubules should be injected from the ureter,
white (lead) injection being used; and con-
siderable force' is required to make a good
injection, but this must be very gradually ap-
plied. Frey recommends the cold ferridcya-
nide injection, or carmine with glycerine or
gum. The tubules can be well examined by
boiling pieces of the kidney with very dilute
sulphuric acid, or in alcohol mixed with
muriatic acid ; or by digestion in cold con-
centrated muriatic acid, the pieces being
subsequently macerated in water, to remove
the acid.

The kidneys of the smaller and lower
animals are best injected from the heart.
The' usual staining processes are very useful.

BIBL. Kolliker, Mik. An. ii. ; Bowman,
Phil. Tr. 1842; Johnson, TodcTa Cyclop.
art. Een\ Toynbee, Med. Chi. Tr. xxx. ;
Forster, Path. Anat. ; Frerichs, Brightsche
Nierenkrank. ; Gairdner, Edinb. M. Jn.
viii. ; Todd and Bowman, Phys. Anat. ;
Henle, Abh. Gesells. Wist. Gottin. x. ;
Ludwig, . Strieker* 8 Handb. i. 489 ; Rind-
fleisch, Path. 18/8, 434; Gross, Structure
Mic. du Rein, Strasbourg, 1868; Frey,
Mikr. 1881, and Histol 1876, 554.

KIRK'BYA, Jones.— A small bivalved
Entomostracan, of the Leperditiadas family,
and nearly allied to Beyrichia. The valves
ridged longitudinally and concentrically,
often reticulated superficially, and impressed
with a subcentral pit. Fossil in the Palaso-
zoic rocks, from the Silurian to the Permian,
and often very abundant.

BIBL. R.Jones, Tr.TynesideNat. Club'iv.
134; Ann. N. H. ser. 4, iii. 223.

KNIFE.

[ 451 1

LAFO'EA.

KNIFE, VALENTIN'S. INTRODUC-
TION, p. xxvi.

KONDYLOSTOMA, Duj.— A genus of
Infusoria, of the family Bursarina.

Char. Body elongated, cylindrical or
fusiform, slightly arcuate, the ends obtuse
and depressed, with a very large mouth
margined with stout cilia, and situated late-
rally at the anterior end ; surface obliquely
striated and ciliated.

K. patens (PL 31. fig. 31 ; fig. 32, slightly
compressed).

BIBL. Duj. In/us. 516; Clap, et Lach.
Inf. 244.

KRAUSKS CORPUSCLES.— The ter-
minal bulbs of the nervous plexus and in-
terlacing nerve-fibres of the conjunctiva.
They consist of a connective-tissue sheath
with nuclei, an internal bulb of finely granu-
lar dull-shining material, within which is a
pale terminal fibre with a somewhat thick-
ened end.

BIBL. Krause, U. term. Korper, 1868;
Strieker, Gewebe, ii. 123.

KRITHE;B., C., and R. See ILYOBATES.

LABREL'LA, Fr. — A genus of Phaci-
diacei (Ascomycetous Fungi), growing upon
living leaves. L. Ptarmicce, t)esm., grows
upon the leaves of AchiUea Ptarmica.

BIBL. Berk. Ann. N. H. i. 208, pi. 7.
fig. 7 ; Fries, Summa Veg. 422.

LABYRINTHODON;TA.— A group of
extinct Amphibia. Transverse sections of
the teeth of the species of this group are
beautiful microscopic objects.

BIBL. Owen, Odontography.

LABYRIN'THULA, Cienkow.— A ge-
nus or group of Protozoa. Composed of
microscopic, thin, reticular, colourless, rigid
filaments, on which fusiform bodies glide
very slowly in various directions ; the fila-
ments arise from imbedded globular red or
yellow masses. Two species, on submerged
posts; Odessa.

BIBL. Cienkowski, Arch. mik. An. iii.
274.

LACE-BARK. See THYMELEACEJE.

LACINULARIA, Oken.— A genus of
Rotatoria, of the family Flosculariaea.

Char. Eyes two (when young); urceolior
gelatinous sheaths aggregated into a spheri-
cal mass ; rotatory organs with two lobes.

L. socialis (PI. 50. fig. 15). Urceoli ge-
latinous, yellowish; rotatory organ veiy
broad, in the form of a horseshoe {fr. wat. ;
length 1-36".

BIBL. Ehrenb. Inf. 403; Huxley, Mic.
Jn. 1852 ; Leydig, Siebold und Koll. Zeit.
1852 ; Ukedem, Ann. Sci. N. 3 se"r. 1851 j
Cubitt, M. Mic.Jn. 1872-73.

LACRYMA'RIA, Bory.— A genus of
Infusoria, of the family Trachelina, Clap, et
Lach.

Char. Body rounded behind, not ciliated ;
with a long and slender neck, which is
dilated at the end, and furnished with a
ciliated mouth and a lip, but no teeth
(= Trachelocerca without a tail).

L. proteus, syn. L. olor. Body oblong,
turgid, colourless, with delicate oblique
striae ; neck very long ; freshwater ; length
1-140''.

Two doubtful species : one (L. guttd)
colourless and without striae; the other
(L. rugosd) containing green matter, with
the body wrinkled. Claparede describes
two other species.

BIBL. Ehrenb. Inf. 309; Duj. Inf. 468;
Clap, et Lach. Inf. ; Kent, Inf. 517.

LACTA'RIUS.— A genus of Hymeno-
mycetous Fungi, distinguished from Agari-
cus by the inner substance of the gills
(trama) being vesicular instead of filamen-
tous. Most of the species abound in milky
juice; and several of them are esculent.
Amongst the most approved is L. deliciosus,
remarkable for its bright orange-coloured
milk. Some acrid species, however, as L.
piperitus, are largely consumed in Russia,
having first in general been preserved in
salt and vinegar. The milk is contained in
peculiar vessels, similar to the laticiferous
vessels of Phanerogams. See LATICIFE-
BOUS TISSUE.

BIBL. Fr. Epicr. 333 ; Berk. Outl. 203 ;
Cooke, Handb. 206; Corda, Jc., fasc. 4,
pi. 10. fig. 139.

LACTATES. See the bases lactate of
lime (PI. 11. fig. 19), lactate of zinc (fig.

LACTEALS. See VILLI.

L^EMAR'GUS, Kroyer,— A genus of
Crustacea, of the order Siphonostoma, and
family Cecropidas.

L. muricatus. Found upon the sun-fish
(Orthagoriscus mold). Length of female 1";
male much smaller.

BIBL. Baird, Brit. Entomos. p. 293.

LAFO'EA, Lamx. — A genus of Lafoeidae,
of the suborder Thecaphora (or Hydroida
with true calycles).

Char. Stem a simple creeping tubular
fibre, or erect and composed of many tubes
aggregated together, rooted by a filiform

"2G 2

LAFOEID^E.

[ 452 ]

LAOM^DEA.

stolon ; hydrothecae tubular, sessile, or with
a short pedicel ; without an operculum ;
polypites cylindrical, with a conical pro-
boscis. There are five British species.

BIBL. Hiucks, Brit. Zooph. p. 198.

LAFOE'IDyE.— A suborder of Hydroida.
See LAFOEA.

LAGE'NA, Walker & Jacob.— A uni-
locular (rarely bilocular) hyaline Foramini-
fer, of the Nodosarine group, generally flask-
shaped. The shell may be subglobular,
oval, oblong, or fusiform ; round, com-
pressed, or angular in section ; variously
ornamented with ribs, network, tubercles,
and spines ; open at one or both ends, with
or without a neck, and often with the tube
turned inwards (Entosolenian). Recent
and fossil all over the world. Lagena Icevis
(PL 23. f. 22) is a typical and very common
form. L. (Entosolenid) globosa (f. 23), with
the neck-tube introverted, is another very
common variety. L. striata (f. 24) is an
elongato-apiculate variety, delicately costu-
late. L. semistriata (f. 25) is L. globosa
with short basal ribs. L. squamosa (f. 26)
was so called because the early microscopes
showed the pitted reticulation as raised
scales. L. scalariformis (f. 27) has a bold
hexagonal niesh ornament. The last is
recent, and the others are both fossil and
recent.

BIBL. Carpenter, Introd. 156 ; Parker &
Jones, Phil. Tr. civ. 345; P., J. & Brady,
Mon. Crag Foram. 28.

LAGENEL'LA, Ehr.— A genus of Infu-
soria, fam. Cryptomonadina.

L. euchlora (PI. 31. figs. 35 & 36) has a
carapace with a beak or neck like that of a
bottle, and a red eye-spot ; freshwater ;
length 1-1150"; probably an Alga-spore.

BIBL. Ehr. Inf. 45; Duj. Inf. 333.

LAGENIP'ORA, Hincks.— A genus of
Cheilostomatous Polyzoa, fam. Pormidae.

L. socialis, on shells of the scallop (Pecten
maximus) ; Hastings. (Hincks, Polyz. 235.)

LAGENGE'CA, Kt.— A genus of Fla-
gellate Infusoria.

Char. Solitary, with a collar, in a protec-
tive sheath.

L. cuspidata (PI. 53. fig. 21), amber-
coloured ; pond water. (Kent, Inf. 359.)

LAGE'NOPHRYS, Stein.— A genus of
Vorticellina (Infusoria).

Char. Capsules not stalked, attached by
the side to other bodies ; body suspended
from the narrow orifice. L. vaginicola, on
the tail of Cyclopsine-, 2 other species on
Gammarus. (Stein, Infus. 1854.)

BIBL. Stein, Inf. 1854, 88; Pritchard,
Inf. 604 ; Claparede et Lach. Inf.

LAGO'TIA, Wright, =FBEI A. Wright,
Edin. Ph. Jn, 1858.

LAGY'NIS, SchvHtzet=Eufflypha pt.

LAGY'NUS, Quenn.— A genus of Holo-
trichous Infusoria. Free, flask-shaped, with
an oral circle of longer cilia ; neck ringed.
L. elegans, freshwater. (Kent, Inf. 520.)

LAMINA 'HI A, Lamx.— A genus of La-
minariaceae (Fucoid Algae), with large, flat,
stipitate fronds, several species of which are
common on rocky shores, attached to rocks
and stones. L. saccharina has a riband-
shaped frond, growing from 2 to 12 feet
long. L. digitata has a broad frond, 1 to
5 feet long, cut into a variable numb or of
segments. The internal structure presents
three layers, the outermost forming a kind
of epidermis. The sporanges (spores of
authors) contain ciliated zoospores which
reproduce the plant. They are little elon-
gated sacs, nestling between epidermal cells
of peculiar structure, standing perpendicu-
larly upon the central substance of the
frond. In L. saccharina the presence of
the sporanges is denoted by a longitudinal
brown mark in the centre of the frond ; in
L. digitata they occur in flat patches on the
extremities of the digitations. The zoo-
spores are little olive-coloured bodies, with
an anterior and posterior cilium. Thuret
has seen them germinate.

BIBL. Harvey, Mar. Alg. 29, pi. 4 ; Phyc.
Br. pi. 192, 223, 241 ; Greville, Alg. Brit.
t. 5 ; Thuret, Ann. Sc. Nat. 2 se*r. xiv. 240,
pi. 30. figs. 1-4 ; Henfrey-Masters, Bot.

LAMINARIA'CE^E.— A family of Fu-
coideae. Olive-coloured inarticulate sea-
weeds, whose sporanges are superficial,
either forming indefinite cloud-like patches,
or covering the whole surface of the frond.
Brit, genera :
* Frond stalked, the stalk ending in an

expanded leaf-like portion.

Alaria. Leaf membranous, with a carti-
laginous midrib.

Laminaria. Leaf simple or cleft, without

a midrib.
** Frond simple, leafless.

Chorda. Frond cylindrical, hollow, with
transverse partitions.

LAMINOSIOP'TES, Megn.— A genus of
Acarina, allied to Sarcoptes.

L. gallinarum occurs in the subcutaneous
tissue of the Gallince(b[egmii?Paras. 151, fig.).

LAOMEDE'A, Lamx.— A genus of Hy-
droid Zoophytes, family Campanulariidae.

LAOPIIONTE.

[ 453 ] LATICIFEROUS TISSUE.

Char. Polypidom rooted, erect, jointed ;
the joints ringed and incrassate; cells alter-
nate, campanulate, on short peduncles ;
vesicles axillary; embryos rnedusiforni.

Six British species : dichotoma (ovicell,
PL 33. fig. 4 c), geniculata, gelatinosa, obliqua,
Flemingii, and lacerata. Found upon marine
Algae, stones, &c., between tide-marks.

BIBL. Johnston, Br. Zooph. 101 ; Gosse,
Mar. Zool ii. 24 ; Hincks, Br. Zooph.

LAOPHON'TE, Philippi.— A genus of
Copepodous Entomostraca. Eight species, in
dredgings. (Brady, Copep., Ray Soc. ii. 70.)

LAR, Gosse. — A genus of Hydroid Zoo-
phytes.

Char. Bodies fusiform, sessile, with two
tentacula springing from the base of a bilo-
bate proboscis, developed on a creeping and
anastomosing stolon,

Lar sabeUarum. The polypites bear a
close resemblance to the human figure.

BIBL. Gosse, Linn. Tr. xxii. 113, tab. xx. ;
Hincks, Br. Zooph. 36.

LAREL'LA, Ehr. — A genus of Rotifera,
fam. Brachionea.

Char. Body with equal setae and three
long fine hairs on each side of mouth ; two
frontal eyes ; length 1-190 to 1-280".

BIBL. Pritchard, Infus. 712.

LARVAE. — In animals which pass
through certain marked stages of develop-
ment, or undergo metamorphosis, as it is
called, the condition in the first of these
stages is called the larval state, and the
animal itself is called a larva.

The aquatic larvae of several insects are
well-known microscopic favourites on ac-
count of their transparence, which allows
the action of the dorsal vessels, with the
circulation of the nutritive liquid, to be
seen, and their curious respiratory organs.
A few of the more common aquatic larvae
and their parts are represented in PL 35.
figs. 1, 14-17, 19-22, 29; these are noticed
more in detail under their respective
heads.

The aquatic larvae of some Amphibia are
admirable objects for exhibiting the circu-
lation of the blood, the development of
tissues, &c., as those of the frog (tadpoles)
and of the Triton.

LASIOB'OTRYS,Ktz.— A genus of Peri-
sporacei (Ascomycetous Fungi).

L. Loniceree grows on the living leaves
and stems of various kinds of Honeysuckle,
forming little heaps seated on a tuft of ra-
diating filaments. The so-called peridioles
appear to be sclerotioid bodies, the superfi-

cial cells of which are converted into true
perithecia, becoming free on the surface :
these contain numerous asci when mature ;
but the spores have not been observed.

BIBL. Berk. Br. Fl. ii. pt. 2. 324 ; Ann.
N. H. 2 ser. ix. 386, pi. 12. fig. 44 ; Fries,
Sum. Veg. 406 j GreviUe, Sc. Crypt. Fl. pi.
191.

LASTR^EA, Presl.— A genus of Aspi-
dieae (Polypodiaceous Ferns), now consoli-
dated with NEPHRODIUM.

LATEX.— The name applied to the pe-
culiar juices, becoming milky when ex-
posed to air, contained in the ' milk- vessels,'
or laticiferous canals of plants, especially
abundant in Euphorbiaceae, Papaveracese,
Cichoracese, &c. It appears to consist of a
watery fluid, with albumen in solution, in
which float globules of caoutchouc, or analo-
gous gum-resinous matter, of variable size,
occasionally mixed with starch-granules of
peculiar forms, as in Euphorbia (PL 48.
fig. 23). According to Sachs and Hanstein
it is a fluid which contains matters of a
directly nutritive character and others which,
are excrementitious in their nature. Trecul,
on the other hand, appears to consider that
the latex is the residue of the sap after
elaboration by the cells. See LATICIFEROUS
TISSUE.

BIBL. Schultz, Vaisseaux latici feres d.
Plantes, 1841 ; Mohl, Bot. Zeit. 1843; Ann.
N. H. xiii. 441.

LATHONU'RA, Lilljeborg.— A genus of
Cladocerous Entomostraca.

Char. Carapace obovate, not produced,
ventral margin furnished with peculiar
flattened spear-shaped plates attached to
the edge. I Irish species.

BIBL. Norman & Brady, Monogr., Nat.
Hist. Tr. Northumb.

LATHRJEA. — A genus of Orobancha-
ceous Flowering Plants. L. squamaria, a
remarkable plant, found here and there in
beech-woods in England, has been the sub-
ject of much research as regards embryo-
logy, by Schacht and others. See OVULE.

LATICIFEROUS TISSUE, DUCTS, CA-
NALS, or VESSELS. — These names are applied
to the tubular and often ramified canals in
which the milky juice or latex of many
plants is contained (figs. 388, 389). The na-
ture, or rather the origin, of these canals is
still a matter of dispute. The ducts present
themselves in various forms, especially in
the rind and pith of the Apocynaceee,
Asclepiadaceae, Moraceae, Urticaceae, Pap;i-
veraceae, Cucurbitace83,Euphorbiacese, Aroi-

LATICIFEROUS TISSUE. [ 454 ]

LAURENCIA.

deee, &c. Simple unbranched milk-vessels
occur in the pith of the elder.

Schacht regards them all as liber-cells.
They have also been considered intercel-
lular passages, originally devoid of a proper
coat, but subsequently acquiring one of vari-
able thickness, derived apparently from the
secretion which they contain ; yet the pre-
sence of transverse partitionswould invalidate

Fig. 388.

Fig. 389.

Fig. 388. Laticiferous canals from the root of Dan-
delion. Magn. 100 diams.

Fig. 389. Laticiferous tissue extracted from Chelido-
nium majus. Magn. 100 diams.

this view. linger, however, imagines that,
while some are formed in this way, they are
mostly developed out of confluent rows of
cells, like the dotted ducts ; and Tr^cul is
of opinion that they are ordinarily formed
in this way. Dippel considers that they
replace the clathrate cells of other plants.

Canals bounded by a defined coat of cel-
lular tissue, forming intercellular canals or
ducts of very definite character, occur in the
Coniferae, the Guttiferae, Anacardiaceae, &c.
These will be spoken of under SECRETING
ORGANS OF PLANTS.

Canals containing a milky juice occur in
some of the Fungi, as in the fleshy sub-
stance of some Agarics, Lactarius, &c.

It was declared some years ago by Schultz
that a regular circulation of the latex takes
place through the ramified laticiferous ducts.
This was chiefly supported on observations
of movements of the latex which may be
made on tolerably transparent parts of
living plants containing these ducts. By

bringing the uninjured sepal of Convolvulus
or a leaf of Chelidonium under the micro-
scope (placing it in oil is advantageous in
the latter case), the branched latex-ducts
may be made out, and a flowing movement
of the particles may bo seen occasionally.
But this has been shown to depend upon a
disturbance of the equilibrium by external
causes, such as pressure and heat, and may
be produced at will in any direction by
mating an incision, towards which the juice
flows. Trdcul thinks that the laticiferous
canals communicate freely with the pitted
ducts and other vascular elements, and take
a share in a kind of circulation, wherein
they play the part of venous reservoirs ; but
his views do not appear to us well founded.

BIBL. Schleiden, Princip. of Bot. 1849 ;
Unger, An. und Phys. 1846, 54; Schacht,
Monat. Berlin Akad. 1856; Flora, 1857, 89;
Meyen, Secretionsorgane, 1837, 63 ; Trecul,
Ann. Sc. Nat A se*r. vii. 290; Hanstein, Milch-
saftgefasse, 1864 ; Dippel, Milclis. 1865 ;
Vogel. Jahr. wiss. Bot. v. 31 ; Sachs, Bot.
88.

LAURENCIA, Lamx.— A genus of Lau-
renciaceae (Florideous Algae), containing
several British species, mostly common, of
yellowish-green, purple, or pink colour, the
fronds pinnately branched, of solid paren-
chymatous structure. The ceramidia are

Fig. 390.

Laurencia dasyphylla.

Eamuli containing tetraspores.

Magnified 50 diameters.

borne on the smaller branches, as are also
the antheridia ; the tetraspores are imbedded
in the ramuli (fig. 390). The ceramidia
contain tufts of pear-shaped spores; the

LAURENCIACEJE.

[ 455 ]

LEAVES.

tetraspores are tetrahedrallr divided. The
antheridia are tlius described (in L. tenuis-
sima) by Thuret : on the smaller branches,
similar to those which bear the ceramidia
on other individuals, occur greyish convo-
luted plates of cellular tissue, of irregular
form, bordered by a line of roundish cells,
containing generally a yellow liquid. Hya-
line cells containing antherozoids are im-
planted vertically on these plates, clothing
both surfaces. The antheridium has a sort
of pedicel formed of an ovoid cell, which
also bears a dichotomous hair, like those
common over the branches of this plant.
The antherozoids are elongated- ovoid, a
little constricted at one extremity, length
about 3-5000". Derbes and Seller have
observed them on L. pinnatifida and other
species.

BIBL. Harvey, Mar. Alg. 97, pi. 12 C ;
Phyc. Brit. pi. 55 ; Grev. Alg. JSt\ 108, pi.
14 ; Derbes and Solier, Ann. So, Nat. 3 ser.
xiv. 276, pi. 37 ; Thuret, tb. xvi. 65, pi. 7,
ib. ser. 4. iii. 19.

L AURENCIA'CE^E.— A family of Flo-
ridese. Rose-red or purple sea-weeds with
a cylindrical or compressed, rarely flat, li-
near, narrow, areolated, inarticulate, or con-
stricted and chambered, branching frond
composed of polygonal cells. Fructification :
1, conceptacles (ceramidia} external, ovate,
furnished with a terminal pore, and con-
taining a tuft of pear-shaped spores j 2, te-
traspores immersed in the branches and
ramuli, scattered without order through the
surface cells ; 3, anther idia.

British genera :

Bonnemaisonia. Frond solid, filiform,
rose-red, much branched; brancheamargined
with subulate distichous cilia.

Laurencia. Frond solid, cylindrical or
flattened, purplish or yellowish, pinnatifid,
ramuli blunt.

Chrysimenia. Frond hollow, filled with
mucus, neither constricted nor chambered.

Chylocladia. Branches hollow, with mucus,
constricted at intervals.

LEA'IA, Jones. — A fossil Entomostracan
Bivalve, of unknown alliance, probably a
Phyllopod. Valves oblong; marked with
two obliquely transverse, divergent ridges,
concentric lines of growth, and intermediate
reticulation. Known in the Coal-measures
of Britain and America.

BEETL. Jones, Fuss. EstJierice, 1862, 115 j
Ge 61. Maq. vii. 219.

LEANGIUM, Lk. See DIDEEMA.

LEATHE'SIA, Gray.— A genus of My rio-

nernaceae (Fucoid Alg£e), consisting of glo-
bose or lobulated fleshy or horny structures,
growing upon rocks, either solid, or, by tha
solution of the internal filamentous sub-
stance, ultimately hollow. The fronds are
composed of masses of dichotomous fila-
ments radiating from a point ; in the olive-
coloured tufted species cohering laterally,
and forming the soft, fine coat of the lobes.
The sporanges are simple oval sacs attached
to the ends of branches of the radiating
filaments, between which they nestle ; or
multilocular, consisting of short septate fila-
ments occurring in similar situations, which
are said by Thuret to be more common j and
the two kinds have not been met with
together.

BIBL. Harvey, Mar. Alg. 48, pi. 10 C ;
Engl. Bot. pi. 1596 ; Thuret, Ann. So. Nat.
3 ser. xiv. 237, pi. 26. figs. 5-12.

LEAVES. — The microscopic structure of
leaves presents a wonderful variety of con-
ditions, from the most simple up to very
complex. Instances of the former are seen
in the MOSSES, JuNGERMANNiE.E,and other
Flo werless plants, where merely a simple cel-
lular plate exists. In the simpler leaves of

Fig. 391,

V T

Vertical section of a leaf of a Melon.
E. S, superior epidermis ; P. S, subjacent close paren-
chyma ; M, infra-stomatal air-space ; L, intercellular
space; F. v, nbro-vascular bundle (rib or yein ) ; P. t,
inferior lax parenchyma; E. t, inferior epidermis; P,
hairs ; ST, stoma.

Magnified 100 diameters.

Ferns, such as HYMENOPHYLLUM, we have
a cellular plate traversed by vascular ribs.
In SPHAGNUM (among the Mosses) the sim-
ple leaves have cells containing a spiral

LECANORA.

[ 456 ]

LEIBLEIXIA.

fibre. In the more complete forms we dis-
tinguish an epidermis, above and below,
often differing in character on the two faces
(see EPIDERMIS and STOMATA), together
with the diachyma or intervening cellular
mass, which varies in its characters in dif-
ferent plants, and is traversed by the fibro-
vascular ribs or veins. The epidermis ex-
hibits GLANDS, HAIRS, &c., in different con-
ditions and forms, which cannot be enume-
rated again here, many of the most inter-
esting forms being mentioned under the
above heads. For observing the structure
of leaves, when consisting of more than a
simple cellular plate, horizontal and vertical
sections are required. The latter are easily
made with a sharp razor in thick and firm
leaves ; but with delicate kinds it is neces-
sary to split a soft cork, to place the leaf
carefully between the pieces, and then to
slice both together, placing the fragments
in water and picking out the pieces of the
leaf with a needle. Many small simple
leaves make good objects by drying, soaking
in turpentine, and mounting in balsam ; the
same may be done with petals, sepals, &c.
The leaves of many water-plants, such as of
Vallisneria, Anacharis, Ceratophyllum, Hot-
tonia, &c., are very favourable for the ob-
servation of the rotation of the cell-sap (see
ROTATION). They are of very simple cel-
lular structure, having no epidermis, sto-
mata, or fibro-vascular ribs.

Leaves also afford a large field for inter-
esting study to the microscopist, in the
examination of the colouring-matters and
secretions in the cells, especially during the
autumnal changes, of the development, &c.,
and moreover in the investigation of the
parasitic Fungi which so frequently attack
them both in the living and the decaying
state.

LECAN'ORA, Ach.— A genus of Le-
canorei (Lichenaceous Lichens), the species
growing chiefly on rocks, stones, and earth.
Thalluscrustaceous, granular, rarely radiate ;
apothecia lecanorine ; paraphyses distinct ;
thecae either eight-spored or polysporous;
spores simple.

BIBL. Hook. Br. Flor. ii. pt. 1 ; Engl. Sot.
pi. 940; Leighton, Lich. 1879.

LECID'EA, Ach.— A genus of Lecideinei
(Lichenaceous Lichens), containing nume-
rous British species. The apothecia have a
border of the same colour as the disk.
Growing chiefly on rocks, sometimes on
bark. L. geograpliica, growing on subalpine
recks, is a rejnarkable species.

BIBL. Hook. Br. Fl. ii. pt. 1. 177 ; Engl.
Bot.pl. 24o, &c. ; Leighton, Lich. 240.

LECIDEI'NEL— A tribe of Lichenacei,
containing the genera Leddea, Odontotrema,
and Schizoxylon.

BIBL. Leighton, Lich. Fl. 240.

LECYTH'EA, Le>. See UREDIXET.

LEECH. — Two species of the genus Hi-
rudo, which belongs to the class Annulata,
are used for medicinal purposes, viz. H. me-
dicinalis, in which the ventral surface is
greenish, with black spots ; and //. offid-
nalis, in which these spots are absent.

The structure of the mouth of the species
of Hiwdo is curious. The mouth is trian-
gular (PI. 22. fig. 25), and placed in the
middle of the anterior sucker. Each of its
three sides is furnished with a semicircular
jaw, of cartilaginous consistence (fig. 26,
side view ; fig. 27, view from above), upon
the convex margin of which are placed a
large number of partly calcareous teeth
(fig. 26 b) arranged in a row. The teeth
(fig. 28, a side view, b view from above)
are flattened, somewhat triangular, and ex-
cavated at the base, so as to exhibit two
short prongs (d). They are placed trans-
versely upon the jaws, which are moved by
powerful muscles, and thus produce the
well-known wounds. And this cross di-
rection of the teeth is probably the cause of
the troublesome bleeding accompanying the
bite of a leech, in consequence of the
amount of laceration necessarily connected
with it.

The species of Hirudo have ten minute
eyes, arranged in the form of a horseshoe
at the upper part of the anterior sucker.

The ova of leeches are deposited in a kind
of cocoon, composed of triangular fibres,
branched and interwoven so as to somewhat
resemble a sponge, as which one of them
was formerly described.

BIBL. Bnghtwell, Ann. N. H. 1842, ix.
11 ; Brandt and Ratzeburg, Mediz. Zool. ii. ;
Johnson. Medicinal Leech ; Moquin-Tandon,
Monog. Hirudinees ; Savigny, Descript. de
TEgypte^TU.. ; Audouinand Milne-Edwards,
Ann. Sc. Nat. 1823, 27-30 ; R. Jones, Outl.
of An. Kingdom ; Gervais and Van Beneden,
Zool. Med. ; Schultze, Zeits. iviss. Zool. xii.
1862; Leuckart, Mensch. Parasit. ; Gratiolet,
Ann. Sd. Nat. iv. 17 ; Lankester, Qu. M.
Jn. 1880, xx. 307.

LEIBLEI'NIA, Endl.— A genus of ma-
rine plants, placed among the Ectocarpaceze
by Endlicher, and among Oscillatoriacea3
(Confervoid Algae) by Kiitzing, who includes

LEIOSOMA.

C

Fig. 392.

Fig. 393.

under it many of the species of Calothrix of
other authors. Endlicher cites only C. con-
fervicola, Ag., and another not British.

It is a minute, glaucous, tufted plant,
formed of short, rigid, erect, subulate fila-
ments, and is common, epiphytic on marine
filamentous Algae.

BIBL. Endl. Gen. Plant. Supp. iii. No. 69 j
Kiitz. Sp. Alg. 276; Harvey, Phyc. Br.
223, pi. 23 C.

LEIOSO'MA, Koch.— A genus of Ori-
batea; has the cephalothorax with plates,
the tarsi with three heterodactyl claws;
two species. (Murray, EC. Entom. 216, fig.)

LEJEUX'IA, Libert. — A genus of Jun-
germannieae (Hepatic*), containing several
rare British species, found in subalpine dis-
tricts, viz. L. serpyllifoUa, hamatifolia, mi-
nutissima, and calyptrifolia. The last is one
of the smallest of the British Jungerman-
niese, and is remarkable for the peculiar
form of its leaves, which resemble the ca-
lyptra of a moss (figs. 392, 393).

Lejeunia calyptrifolia.
Pig. 392. Stem with calyptriform leaves, an immature

S'ant (on the right), and a burst sporange.
agn. 5 diams.
Fig. 393. A leaf of ditto. Magn. 25 diams.

BIBL. Hook. Br. Jung. pis. 42, 43, 61,
52 ; Br. Fl. ii. pt. 1, 127.

LEMANI'E^E.— A family of Confervoi-
deae. Olive-coloured freshwater Algae, fila-
mentous, inarticulate, of cartilagineo-coria-
ceous substance, and compound cellular
texture. The fronds branched, hollow, bear-
ing within at irregular distances whorls of
wart-like bodies consisting of tufted, sim-
ple or branched, necklace-shaped filaments
(fig. 394), arising from the inner wall of the
tubular frond, and finally breaking up into
elliptical spores. British genus :

Lemania. Character the same as of the
family. Two species have been found in

7 ] LEMON.

Britain, L. torulosa, Ag., and L.fluviafih's.
They always grow in clear running streams.
Thwaites has made some interesting obser-
vations on the development of these plants.

Fig. 394.

Lemania torulosa.

Section of frond, showing the tufts of fertile filaments.
Magn. 50 diams.

See COMPSOGON.

BIBL. Hassall, Alg. 68, pi. 7 ; Kiitz. Phyc.
gen. 271 ; Thwaites, Ann. N. H. 2 ser. i.
460 ; Wartmann, Anat. d. Lemania, 1854 ;
Rabenhorst, Alg. iii. 410 ; Sirodot, Lema-
neac. 1875 (23 pis.).

LEMBA'DIUM, Perty. — A genus of
Holotrichous Infusoria.

Char. Body oval, flat, with a broad deep
buccal fossa, having an undulate membrane
on one side.

L. bullinum ; marsh water.

BIBL. Claparede et Lachm. Inf. 251 ;
Kent, Inf. 536.

LEM'BUS, Cohn.— A genus of Holo-
trichous Infusoria. Free, elongate, mouth
ventral; a triangular ventral undulating
membrane. Four species ; marine. (Kent,
Inf. 547.)

'LEM'NA, L. — Duckweed. A genus of
aquatic Monocotyledonous plants, remark-
able for their simplicity of structure, the ve-
getative system being replaced by a minute
leaf -like floating stem, with dependent root-
lets, furnished with a well-developed sheath
(pileoj-kiza.) at the end. The lobes of the
stem bear two monoacious imperfect flowers,
and also propagate by bulbils formed in
the slits in the side of the lobes ; the
young bulbils formed in autumn sink when
the parent dies, and rise again in spring.
Spiral vessels occur abundantly in L.
polyrhiza'i ,they are sparingly present in
the rest.

BIBL. Hook, and Arnott, Brit. Flor.;
Schleiden, Bot. 229; Weddell (Wdffia),
Ann. Sc. Nat. 3 ser. 12, 155.

LEMON, ESSENTIAL OIL OF. — This is
sometimes used in the microscopic examina-
tion of pollen and other structures, which
are placed in it to render them more trans-

LENTICELS.

[ 458 ]

LEPISMA.

parent, being less disagreeable and less vo-
latile than oil of turpentine. Glycerine may
often be substituted.

LENTICELS.— Structures found upon
the surface of young stems, especially of
most of the Dicotyledonous shrubs and
trees. They first appear on the yearling
shoot as little specks, of a different colour
from the rest of the epidermis. Towards
the winter, or in early spring, the epidermis
splits transversely over the lenticels, which
become then slightly projecting papillae,
frequently divided into lips, as it were, by a
median furrow. The surface of the papilla
is now brown ; and it is of corky character
for some little distance inwards. As the
branch grows, the lenticels become drawn
out laterally, so as to appear like cross
striae. They are subsequently lost sight of
by the bark splitting through them, as in
the apple or beech, or by the bark peeling
off (plane).

Microscopic examination of sections shows
that they are mere hypertrophal produc-
tions from the epiphlceum, or suberous layer
of the BARK, and have no connexion with
the liber or cambium. DeCandolle ima-
gined they were root-buds, where adventi-
tious roots might arise under favourable
circumstances ; but this was an error. Du
Petit Thouars thought they were breathing-
pores, replacing the stomata of the epider-
mis; out they are not pores; and many trees,
such as the Conifers, Roses, Euonymus eu-
ropcBuSj &c., have none.

BIBL. DeCand. Ann. Sc. Nat. 1826, vii.
6;Mohl, Vennischt.Schnft. 229, 233 ; Meyer,
Linncea, vii. 447; linger, Flora, 1836, ii.
577 ; St. Pierre, Compt. Rend. 1855 ; Ann.
N. H. 2 ser. xvi. 273.

LEPADEL'LA, Bory.— A genus of Ro-
tatoria, of the family Euchlanidota.

Char. Eyes absent ; foot forked.

Three species.

L. emarginata (PI. 43. fig. 43). Carapace
depressed, oval, anterior portion broad,
emarginate at each end. Freshwater;
length of carapace 1-570".

Teeth of L. ovalis, PI. 43. -fig. 44.

BIBL. Ehr. Infus. p. 457.

LEPEOPHTHI'R U S,Nordm.— A genus
of Crustacea, of the order Siphonostoma,
and family Caligidae.

Char. Fourth pair of legs slender, not
branched, formed for walking ; thorax with
only two distinct joints ; frontal plates
destitute of sucking-disks on the under sur-
face. Six British species, found upon

various marine fishes, as the salmon, mac-
kerel, sole, brill, turbot, &c.

L. pectoralis (PL 19. fig. 23).

BIBL. Baird, Brit. Entomost. p. 273.

LEPERDITIA, Rouault.— An extinct
bivalve Entomostracan, probably Ostra-
codous ; bean-shaped ; smooth ; straight
on the dorsal, convex on the ventral
margin; smaller in front than behind;
right valve overlapping the left along
the ventral edge ; each valve bearing a
pitted and radiate muscle-spot and an
ocular tubercle. The dorsal region of the
left valve is swollen in some species.
Fossil only.

30 Silurian species, 6 Devonian, and 14
Carboniferous, with many varieties.

BIBL. Jones, Ann. N. H. 2 ser. xvii. 81 ;
5 ser. ix. 168 ; M. Mic. Jn. iv. 184.

LEPIDOCYR'TUS, Latr.— A genus of
Thvsanura.

L. curvicollis is one of the insects which
yield the so-called Porfwra-scales. The
first segment of the thorax is as long as the
two next, and projects so as to cover the
neck and part of tlie head. It is found under
stones or old wood. See PODUBA.

LEPIDOP'TERA.— An order of Insects,
consisting of butterflies and moths.

Lepidopterous insects present several
points of interest to the microscopic ob-
server ; among these may be mentioned
especially the proboscis or ANTLiA,the hook
connecting the wings (INSECTS, p. 432), the
wings themselves, and the beautiful scales
covering them (SCALES OF INSECTS, TEST-
OBJECTS). Their larvae or caterpillars are
favourable subjects for the examination of
the internal structure — the tracheae with
their spiracles, the fatty body, the alimen-
tary canal, the spinning organs, the curious
legs, &c.

LEPISMA, Linn.— A genus of Thysa-
nurous Insects, family Lepismenae.

Char. Body elongated, flattened; antennae
setaceous, with numerous very short joints ;
palpi four, long ; abdomen terminated by
three long filaments jointed near their
ends.

L. saccharina (PI. 35. fig. 18). Body
silvery-grey, not spotted, covered with
scales ; caudal filaments speckled with
reddish brown ; antennae about two-thirds
the length of the body.

This active little insect, which runs but
does not jump, is found (in the country)
upon the shelves of cupboards where sweets
and other eatables are kept, in window-

LEPRALIA.

[ 459 ]

LEPTOTHRIX.

cracks, &c. Its habits are nocturnal. Its
beautiful silvery scales are used as TEST-
OBJECTS (PL 1. fig. 6).

There are many other species, the scales
of which probably exhibit the same struc-
ture.

BIBL. Gervais, Walckenaer's Apttres, iii.
p. 450 ; Lubbock, Linn. Trans.

LEPRA'LIA, Johnst.— A genus of Chei-
lostomatous Polyzoa, family Membranipo-
ridae (Escharidae, Hincks).

Char. Polypidom adnate, crustaceous,
formed of a layer of juxtaposed urceolate
cells, closed in front, and spreading cir-
cularly.

The very numerous species form white,
yellow, or reddish crusts upon rocks, shells,
and sea-weeds. Avicularia and vibracula
present in some, but absent in others. Mouth
of cells sometimes with spines.

L. variolosa (PL 41. fig. 17). Cells
oblong, depressed, roughish, interstices
punctured ; orifice semioval or roundish,
margin plain. On stones and shells, com-
mon ; varieties occur with the lower lip
notched, or with a tooth.

L. unicomis. Cells ovate, scaly, with a
short obtuse process or knob above the ori-
fice, which is roundish, with a distinct
notch in the upper margin ; common.

BIBL. Johnston, Br. Zooph. 300 ; Busk,
Mar. Polyz. ; Hincks, Polyz. 297.

LEPTOCLINUM, M.-Edw.— A genus of
Tunicate Mollusea, of the family Botryllidae.

Distinguished by the thin, sessile, in-
crusting mass of variable form, the nume-
rous systems, the six-rayed branchial ori-
fice, and the anal orifices opening into a
common more or less branched cloaca.

Six British species: maculosum, asperum,
aureum,gelatinosum, Listerianum, and punc-
tatum, found upon the roots of Laminaria
and other marine algae ; the two former
common.

BIBL. Forbes and Hanley, Br. Mollusca,
i. 16; Gosse, Mar. Zool. ii. 32 j M.-Edwards,
Mem. snr les Ascicl. comp.

LEPTOCYSTINE'MA, Archer, = Go-
NATOZYGON, De Bary, 1856.

LEPTODIS'CUS/Hertwig.— A genus of
marine Flagellate Infusoria.

L.medusoides, diam.^"; Messina. (Kent,
Infus. 400.)

LEPTOGID'IUM, Nyl.— A genus of
Collemacei (Byssaceous Lichens). L. den-
driscum, on mossy trees on high mountains.
(Leighton, Lick. Fl. 13.)

LEPTO'GIUM.— A genus of Collema-

ceous Lichens. Thallus with a distinct
cortical layer, granula ; gonima monili-
form; apothecia lecanorine; spores eight,
multilocular, rarely simple. Species nume-
rous. On mossy trunks, walls.

BIBL. Leighton, Lich. Flor. 25.

LEPTO'MONAS, Kt.— A genus of Fla-
gellate Infusoria. Free, narrowly fusiform,
flagellum single.

L. Biitschlii, in the intestine of Trilobus
gracilis. (Kent, Inf. 243.)

LEPTOS'CYPHUS, Allman.— A genus
of Hydroid Zoophytes.

Char. Capsules ovato-conic; polypes
cylindrical, proboscis conical ; reproduction
by free medusiform bodies.

L. tennis, on Laminaria ; Stromness.

BIBL. Allman, Ann. N. H. 1864 ; Hincks,
Br. Hyd. Zooph. p. 196.

LEPTOSTRO'MA, Fr.— A genus of
Sphceronemei(StylosporousFungi), probably
consisting only of the younger stylosporous
states of species of HYSTEBIUM or PHACI-
DIUM. Several species are recorded as
British, some common, occurring on the
stems and leaves of sedges, rushes, Pteris,
&c., forming small round flat spots, from
which the upper part of the perithecium
splits off, leaving a little margined scar, in
which are seated the stylospores.

BIBL. Berk. Br. ^Y/ii.pt. 2. 297; Ann.
N. H. i. 257, vi. 365 ; Tulasne, Ann. N.
H. 2 ser. viii. 114.

LEPTOTHRICH'E^.— A subfamily of
the Oscillatoriaceae. Filaments very fine,
adnate, sheathed, indistinctly articulate ;
movement slow ; solitary or fasciculate ;
for the most part in broad and diffused
layers.

BIBL. Eabenhorst, Fl. Alg. ii. 8 & 73.

LEP'TOTHRIX,Kutz.— A supposed ge-
nus of Oscillatoriaceae. Found on damp
stones, among wet plants, and in foul water ;
very probably consisting of the mycelial
filaments of mildew Fungi.

The filaments are very slender, simple,
continuous or obscurely jointed.

L. ochracea, K. (Oscttlatoria ochracea,
Grev.) is an obscure production, forming
yellowish-brown flocculent masses, common
in boggy pools.

L, buccalis and L. insectorum, Ch. Robin,
probably belong to some Fungus.

BIBL. Kiitz. Sp. Alg. 262 ; Tab. Phyc. i.
pi. 61. fig. 1 ; Robin, Vegtt. Parasit.
2nd ed. 345, 355; Mettenheimer, Mus.
Senckenb. 1857, 139 ; Moggridge. Jn. M. 8.
1868.

LEPTOTIIYR1UM. [ 460 ]

LEUCOPIIRYS.

LEPTOTIIY'RIUM, Kutz.— A genus of
Sphaeronemei (Stylosporous Fungi).

L. jualandis, Lib., L. frag aria, and
L. ribis have been found in ' Britain ; they
are probably stylosporous forms of Asco-
mycetes.

BIBL. Fries, Sum. Veg. 371, 423; Berke-
ley, Ann. N. H. 2 ser. v. 371 ; Tulasne,
Ann. Sc. Nat. 4 ser. v. 115.

LEPTOTRICHA'CE^E.— A family of
operculate Acrocarpous Mosses, branching
by innovations, or with the fertile summits
several times divided. Leaves lanceolate
or awl-shaped, often canaliculate-concave,
with a nerve, mostly flattened or terete ;
cells prosenchymatous, often mingled with
parenchymatous, lax or firmish, empty, not
unfrequently thickened at the apex, then
square. Capsule ovate or cylindrical, some-
times naked, sometimes erect, often stru-
mulose at the base ; operculum conical or
subulate. Differing from Dicranaceae in the
absence of alar cells to the leaves. Brit,
gen.:

Angstrcemia, BracJiyodus, Campyloste-
lium, Leptotrichum, Seligeria.

LEPTO'TRIOHUM, Hampe .— A genus
of Acrocarpous operculate Mosses, including
certain Didymodonta and Trichostoma of
other authors.

LEPTOTRICHUM, Corda.— A genus of
Sepedonei (Hyphomycetous Fungi) j not
British.

LEPTUS, Lam. See TROMBIDIUM.

L. autumnalis (Trombidium autumnale),
the harvest-bug.

LERN^EA. — A genus of Pcecilopoda
(Crustacea).

L. branchialiS) on the gills of the cod.
(Baird, Br. Entom. 344.)

LERNEONE'MA, Edwards.— A genus
of Siphonostoma (Crustacea).

Char. Body long, slender, narrowed an-
teriorly in the form of a neck, terminated
by a swollen head, with two or three
simple, curved, horn-like appendages ; abdo-
men of inconsiderable length, simple ; ovi-
ferous tubes long and slender.

Two British species : L. spratta (PI. 19.
fig. 24), length 2 inches ; andZ. encrasicholi.
Both found upon the sprat.

BIBL, Baird, Brit. Entomostraca, 339.

LESKEA, Hedw.— A genus of Mosses.
See HYPNUM.

LEUCINE, or caseous oxide, is a normal
constituent of the lungs, spleen, pancreas,
the salivary glands, &c., and is produced
during the putrefaction of albuminous and

gelatinous matters. Usually accompanied
by tyrosine, it crystallizes in minute spheres,
which frequently unite and form radiating
clusters, which often present a yellow tin<re
and a concentric lamination. It is soluble
in water, less so in alcohol. The alkaline
pancreatic juice transforms albumen into
leucine and tyrosine. It also occurs in the
Crustacea, Arachnida, and Insecta.

BIBL. Frey, Hist. 49; Rindflrisch,
Path. Hist. 14 ; Voit, KoU. $ Sieb. Zeitsch.
ii. 1868.

LEUCO'BRYUM, Hampe.— A genus of
Bryaceae, Acrocarpous Mosses,but exhibiting
also lateral fruit-stalls. Capsule, lid, and
peristome as in Dicranum ; out the leaves
whitish, spongy, and composed of two
layers of cellular tissue, the nerve indistinct.

L. ylaucum. On moist heaths, woods,
&c.

BIBL. Wilson, Bryol. Br. 82.

LEU'COCYTES.— These are the colour-
less corpuscles of the blood, lymph, &c.

LEU'CODON, Schw03gr.— A genus of
Pleurocarpous Mosses.

Char. Capsules oval, erect, pedicel short,
calyptra large ; outer teeth 16, bifid or
perforated, not hygroscopic : shoots simple ;
leaves plicato-striate, nerveless.

L. sciuroides, trunks of trees and walls,
frequent ; L. Layurus. rare. (Wilson, Bryol.
Br. 313.)

LEU'COPHRYS, Ehr.— A genus of the
family Bursarina (Ciliated Infusoria.)

CJtar. No sheath ; body truncated in front
obliquely ; buccal cirri surrounding the
truncation ; anus at the posterior extremity ;
no watch-glass organ ; no rows of cilia in
the interior of the buccal fossa.

Ehrenberg describes eight species ; they
are found in salt and fresh water, both sweet
and putrescent.

L. patida (PI. 31. fig. 38, a dorsal, b ven-
tral surface). Body ovato-campanulate,
hyaline or white, turgid ; mouth large, pa-
tulous. Freshwater and marine. Length
1-288 to 1-96". The alimentary canal,
with the sacculi, according to Ehrenberg's
view, is represented in fig. 31 a.

L. spathula (Spathidium hyalimim, D.)
(PI. 31. figs. 75, 76). Body lanceolate,
compressed, whitish, membranous, obliquely
truncated and dilated in front ; freshwater.
Length 1-144". Dujardin denies the exist-
ence of the anterior row of cilia. A very
doubtful form.

PI. 31. fig. 37 represents L. tfriala, D.,
which is one of the Opalina.

LIBELLULHLE.

[ 461 ]

LIBER.

BIBL. Ehrenb. Inf. 311 ; Duj. Inf. 458 ;
Stein, Inf. 184; Clap, et Lackm. In/us.
1868.

LIBELLULlDvE.— A family of Insects,
of the order Neuroptera. It contains
several common but beautiful insects, some
of which are popularly known as Dragon-
flies and horse-stingers, although they are
harmless. The great interest connected
with them relates to the structure of the
larvae and pupoe, which live in water, and
are furnished with branchiae, either inter-
nal or external, situated at the end of the
body. External branchiae are seen in
Ayr ion (PI. 35. fig. 17), They consist of
three membranous plates (PL 35. fig. 2 g),
traversed by innumerable tracheae. In
jEschna, Libellula, and Calepteryx the
branchiae are internal and situated within
the rectum (PI. 35. fig. 20, rectum of
jEschna). In this last genus the branchiae
are in the form of plates, which are nu-
merous, semicircular, longitudinal, imbri-
cated, and arranged alternately in six regu-
lar and symmetrical columns. The laminae
consist of a network of fine tracheae, com-
municating with those of the body and
situated beneath the mucous membrane.

The end of the abdomen is furnished with
five movable valvular pieces (PL 35. fig. 29),
three of which are larger than the others,
and the uppermost of which is notched at
the end. These pieces, by their contraction,
expel the water from the rectum; it is
renewed ; and the expulsive force effects the
locomotion as well as the respiration of the
insect. The labium of *3$$chna also possesses
a remarkable structure, forming an elongated,
somewhat spatulate, mask-like appendage,
which completely closes the mouth when
unemployed (PL 50. fig. 16). In the other
genera the structure is very similar. In
Libellula six biserial rectal columns are also
present ; but there are no papillae on them ;
and the caudal appendage is pointed and
not notched (PL 35. fig. 22). In Calepteryx
the rectal branchiae are more simple, con-
sisting of three plates attached only by the
end, and resembling in structure the external
plates of Agrion ; the ocelli are distinct ;
and the external caudal aperture consists of
three channelled and keeled pieces. The
spiracles of these larvae and pupae are more
or less concealed in the interspace between
the proto- and mesothorax ; they are trans-
verse, bilabiate, and furnished with a mus-
culo-membranous valve.

BIBL. Dufour, Ann. Sc. Nat. 1852, xvii.

65 ; Westwood, Introd. ; Packard, Amer.
Natur. v. 1871 ; Oustalet, Ann. So. Nat.
xii. ; Selys-Longchamps, Mon. Libell. d' Eu-
rope ; Charpentier, Libell. Europ. 48 pis.:
Lenderfeld, Wings of, 1831.

LI'BER (Phloem).— The term liber-cells
or -fibres is applied to the very long pros-
enchymatous cells, occurring isolated or
in bundles at the outside of the cambium-
layer of Dicotyledons, and often in the pith
and the ribs of the leaves ; to the cells of
similar form and character occurring in the
outer part of the fibro-vascular bundles of
Monocotyledons, and in the branches of those
containing no spiral structures ; also to the
fibrous cells of the same kind found in the
husks of many fruits, as the cocoa-nut ; they
are constantly ringed with sieve-cells or
-tubes. No exact line of demarcation can
be drawn between liber-cells and wood-cells,
since the shorter of the former pass into the
latter. As a rule they are much thickened
by secondary deposits (PL 47. fig. 27) ; but
these deposits are tougher than those of the
wood-cells; and while they have pores, these
are never bordered with a rim. Liber-cells
are not unfrequently found branched (Rhi-
zophoraceae, Gmtum) ; and some of the
branched forms are supposed to originate
by the confluence of originally distinct cells,
after the manner of milk-vessels.

The layers of thickening on the walls of
liber-cells frequently exhibit a spiral stria-
tion, especially after treatment with acids
(PL 28. figs. 2, 3, 25). Mohl has pointed
out the peculiar characters of certain struc-
tures associated with liber in the bark of
Dicotyledons and in the vascular bundles
of Monocotyledons. These are the vasa
propria, and are described under VASCULAR
BUNDLES.

The importance of liber as a material for
textile fabrics has been spoken of under FI-
BROUS STRUCTURES, and examples cited ;
figures of various kinds of liber-fibre are
given in Plate 28.

In Dicotyledonous stems the liber-fibres
are usually placed in large bundles opposite
the fibro-vascular bundles of the wood,
as in Urtica, Viscum, Clematis, Quercus,
&c; j sometimes in small irregular groups,
as in Vinca and Linum ; in other cases they
stand in single rows, alternating with
parenchyma or vasa propria (Cupressinea
and Taxinece), while in many plants they
are irregularly scattered, as in Rhizophora,
Cinchona, Nerium, &c. Isolated liber-cells
occur in the pith of young shoots, and may

LIBER.

[ 462 ]

LICHENOPORA.

be readily seen in the long woody radicles
developed from the seeds of the Rhizopho-
reoe (PL 48. fig. 31) ; and in the bark and
pericarp of Gnetum, isolated branched
liber-fibres occur scattered throughout the
whole mass.

In many Dicotyledons the thick-walled
liber-cells are formed only in the first year,
the subsequent formation in this region
consisting of new layers of vasa propria
and parenchymatous cells (Betula alba
and Faff us sylvatica). In Viburnum Lan-
tana the thick-walled liber is entirely
wanting.

In the Monocotyledons they occur asso-
ciated with short wood-cells in the fibro-
vascular bundles ; but they form alone the
fibrous bundles often intermixed with and
prolonged from the ends of these, occurring
especially in the outer part of the stem of
herbaceous Monocotyledons, such as Lilies
and Grasses, and in the fleshy cortical layer
of rhizomes, as in Sparganium, &c.

In both families they occur with the spiral
vessels and wood-cells in the ribs or veins
of leaves (as in Phormium tenav), bracts,
spathes of Palms, &c.

Liber-cells are generally drawn out very
gradually to a point at each end ; sometimes
they are very long ; Schleiden states he has
seen them 5" or 6". Sometimes they exhi-
bit expansions at particular points, as in
the Apocynaceas. The branched forms
in Rhizophorese, Gnetum, &c. are usually
much shorter than the simple fibres, and
their form is often very irregular (PI. 48.
fig. 31). The diameter varies a great deal
in some plants ; and we should scarcely ven-
ture to say that the microscopic appearance
of a liber-fibre would suffice for the deter-
mination of the material of any (vegetable)
textile fabric, beyond the distinction of
cotton (or vegetable hair} from linen or other
liber ; but reagents affect them differently.
The appearance presented by many kinds
of fibre under the microscope, in the state
in which they occur in commerce and after
treatment with acids, is shown in PI. 28.
figs. 2-7, 25 & 26. The figures are taken
from very characteristic examples ; but many
modifications occur in subordinate quantity.
Flax (Linum usitatissimum) (fig. 2) has the
walls much thickened, with distinct pores ;
it exhibits a very oblique close striation after
boiling with nitric acid. Jute, the liber of
Corchorus capsularis, has thinner walls, with
constrictions at intervals and blunter ends
(fig. 3) j no spiral streaks come out here on

boiling with nitric acid. The fibre from the
Cocoa-nut, husk occurs in bundles (fig. 4) ;
when isolated or boiled with acid, the walls
are found thin, with wide, open, spiral streaks
(slits in the secondary layers) ; the ends are
blunt (fig. 6 a, b). The fibre of hemp ( Can-
nabis sativa) somewhat resembles flax, but
is coarser and becomes swollen up and brit-
tle, readily breaking across, when boiled with
nitric acid (fig. 6) ; no spiral streaks. The
liber-fibres from the bundles of Musa textilis
(fig. 7) are fine and tough, and not much
altered by boiling. Those of Bcelnneria
nivea (fig. 25) are coarse, rough on the out-
side ; they swell up and exhibit marked spiral
slits when boiled with acid, and also distinct
lamination of the thick wall (fig. 25 c). Bceh-
meria Puya (fig. 26) closely resembles the
former ; but the spiral striation is not very
evident, and the wall splits readily in the
longitudinal direction (fig. 26 c). The spiral
striation is well seen in fig. 30 of PI. 48,
which represents the end of a liber-fibre from
Vinca minor after boiling with nitric acid.

The liber-bundles of bark are sometimes
set free as loose stringy fibres by the decay
of the outer parts of the bark, as in the vine,
Clematis, &c. In some plants they take a
wavy course, anastomosing laterally so as to
form connected reticulated sheets over the
cambium : in the Lime (Titia) these sheets
may be detached by maceration, and they
form bast, the material used for matting,
&c. In the THYMELEACEJE (lace-bark
trees) the annual layers of liber can be
detached from each other, and form sheets
of fibrous tissue, sometimes firm and tough,
sometimes almost as delicate as muslin.

BIBL. Mohl, Bot. Zeit. xiii. 873 ; Schacht,
Pftanzenzelle, 208; Ann. Sc. Nat. 4 se"r. viii.
164 ; Sachs, Bot. 121 ; Henf rey-Masters, Bot.

See also under LATICIFEROUS TISSUE.

LICEA, Schrad. — A genus of Myxomy-
cetes, growing on damp rotten wood, in
garden frames, &c., with the peridia elon-
gate, grouped together, of only one layer,
and containing few or no filaments among
the spores. Four species ore described as
British, of which L. fragifornris, Nees, is
not uncommon on wet very rotten wood,
moss, &c.; the groups of peridia just before
maturity somewhat resembling a straw-
berry, afterwards brownish.

B'TBL. Berk. Br. Fl. ii. pt. 2. 321 ; Ann.
N. H. 2 ser. v. 367 ; Greville, Sc. Crypt. Fl.
pi. 328 : Fries, Syst. Mycol iii. 195 ; Sum.
Veg. 458.

LICHENOP'ORA, Def.— A genus of

LICHENS.

[ 463 ]

LICHENS.

Cyclostomatous Polyzoa (Tubulipora, pt.,
Johnst.). Four species ; on marine zoo-
phytes, stones, and shells. (Hincks, Polyzoa,
471.)

LICHENS.— A class of Thallophytes or
cellular plants standing between the Algae

Fig. 395.

Sphscrophoron coralloides.

Thallus with apothecia .

Nat. size.

and the Fungi, exhibiting in the various
genera relations sometimes approaching very

Fig. 396.

Fig. 397.

Fig. 396. Borrera ciliaris. Thallus with apothecia.

Nat. size.
Fig. 397. Opegrapha atra. Thallus with lirellse. Nat.

size.
Fig. 393. Section of thalamium. Magn. 150 diams.

closely to the one, sometimes to the other of

these two classes. The parasitic Lichens,
such as ABROTHALLTJS, being destitute of
a free thallus and of green gonidia, are un-
distinguishable from Fungi by any definite
character.

The Lichens are almost universally either
dry incrusting bodies, growing upon bark
of trees, stones, earth, &c., as a pulverulent,
or rough and horny, or laminated and mostly
wrinkled and curled crust (fig. 397) ; or as
horny or leathery, foliaceous or shrubby,
ragged or bristling patches (figs. 39o & 396),
seldom rising much from the surface which
they overgrow ; of grey, greyish green,
brown, yellowish, or even reddish colour,
and with a dead, pulverulent, and opaque
surface. Some, however, are parasitic on
other Lichens, as Abrothallus, or upon living
leaves, as Strigula. They derive their
nourishment from the air ; and are usually
recognized by their dry crustaceous habit,
and the presence of gonidia.

In the simplest kind of Lichens, the
thallus consists of microscopic branched
filaments (hyphee), penetrating among the
superficial layers of the cells of the bark or
epidermis upon which the plants grow.
These filaments usually present globular
cells here and there arising from them,
filled with green matter, which are capable
of reproducing the plant when detached ;
they are called gonidia, and are regarded as
analogous to the buds of the Fowering
plants and the cellular gemmce of the higher
Cryptogams. The gonidia consist either of
simple cells containing green granular
matter (PI. 37. fig. 6^), or of clusters or
strings of green granules, when they are
called granula gonima (PI. 35. fig. 13).
Sometimes these granules form spherical
concretions upon the thallus, and are called
cephalodia. The gonidia have been stated
to produce zoospores ; while these again are
declared to be granules in molecular motion.
In the simple forms here alluded to, the
gonidia are not sufficiently numerous to give
a coloured tinge to the structure as seen by
the naked eye j in some even the filaments
make no show, while in others they form
whitish patches (Opegrapha, Verrucaria).
In the forms rather more developed we find
a layer of globular epidermal cells, with
whitish contents, closely coherent together,
constituting a " cortical layer " covering the
upper surface, to which the filamentous
structure or liypotTiallus then forms the
" medullary layer." The crustaceous kinds
overgrowing stones have this filamentous

LICHENS.

[ 464 ]

LICHENS.

niedullary layer very solid ; and in some of
them its lowest filaments are seen growing
put all round the borders, in the direction
in which the plant is extending, the upper
filaments with the gonidia and the cortical
layer by degrees overgrowing these lowest
filaments, which in the meantime have
extended further out. Some of the crus-
taceous Lichens grow out in more or less
regular lobes at their borders, and thence
lead to the pseudo-foliaceous forms, of which
the common Parmelia (Physcid) parietina,
the yellow Lichen so abundant on walls,
and Borrera ciliaris, common on branches
of trees (fig. 396), may serve as examples.
The thin paper-like thallus of the former
exhibits four distinct regions (PL 37. fig. 2) :
— 1, on the upper face a layer of thick cells,
firmly connected together, coloured yellow
at the surface (upper cortical or epidermal
layer) ; 2, a layer like the preceding, but
white, forming the inferior surface of the
thallus (lower cortical or epidermal layer) ;
3, beneath the upper cortical layer lie the
gonidia ; and 4, under these lie the medul-
lary filaments forming the central substance,
at the upper part of which lie the gonidia
arising from these filaments. These are in-
terlaced and imprison air between them.
From the lower face arise laminae or fibrous
processes, like roots (rhizinee), serving as
cramps by which the plant attaches itself to
the surface on which it grows. In Peltigera
canina there is no inferior epidermal or cor-
tical layer, the filamentous medullary struc-
ture forming the irregular veined surface,
prolonged here and there into pseudo-radical
processes. In Endocarpon and other fronds
of solid texture, the medullary layer is
formed of slender linear cells, closely packed,
with few air-passages. The species of Cla-
donia exhibit a structure of the thallus
intermediate between that of the foliaceous
kind just referred to and the shrubby sort.
In the foliaceous expansion resting on the
ground, of C. pyxidata, for example, we
detect the upper epidermis, next the goni-
dial layer, which again rests on the closely-
felted filamentous medullary substance. In
the branches of C. rangi/erina, as in a great
number of its congeners, there is no well-
defined epidermis. The branches are tubes,
vacant in the centre, formed of a cartilagi-
nous structure, in which only two zones can
be distinguished, the inner and more solid
of which is composed of almost simple, pa-
rallel, solid filaments intimately glued toge-
ther by mucous substance ; the outer zone

is formed of a felted mass of filaments, like-
wise solid, but branched and divaricated.
The solidity of these filaments arises from
the obliteration of the cell-cavity by second-
ary layers on its walls, giving the filaments
a horny texture. In the outer loose layer
are found scattered groups of gonidia. In
Stereocaulon denudatum the branches are
solid and formed exclusively of parallel
filaments, as is the case also with those of
Ramalina scopulorum. In Evernia vulpina
there is a solid axis formed of parallel fila-
ments enclosed in a layer of interlaced
fibres, between which and the horny coat,
which is either solid or very obscurely cel-
lular, gonidia are here and there to be ob-
served.

In many Lichens, when exposed to excess
of moisture, the proper fructification is not
developed, and the gonidial structure is
produced so abundantly as to burst through
the superficial cortical layer and become
naked, giving a mealy appearance to the
thallus. Lichens reproduced by gonidia
commonly grow at first into a pulverulent
stratum by the multiplication of the cells,
giving rise to the forms which were at one
time thought distinct genera, such as Le-
praria.

The gonidia have been stated to produce
motile zoospores; but these are now con-
sidered molecular granules.

The fronds of Collema are remarkable foi
their gelatinous texture, and approach the
Nostochacese (Algae) in the simplicity of
their structure ; thus, the thallus of C.
clieileum consists of branched and colourless
filaments Or tubes imbedded in an abundance
of mucilage ; in C.jacobecefolium, there exist
in addition very numerous granula gonima,
almost all arranged in long beaded lines
(PI. 37. fig. 13), some being larger than
others, the whole mixed with the con-
tinuous filaments and imbedded in mucus.
Both species have long, whitish, branched,
filamentous pseudo-radical processes.

Putting aside the gonidia or gemmule-
cells of the thallus, the reproductive organs
of the lichens are of three kinds:— 1, the
apothecia, which, according to their forms,
receive different names, and are all charac-
terized by producing the sacs (thecce) con-
taining spores; 2, the spermogonia, which
some regard as antheridia, and which pro-
duce extremely minute cylindrical bodies
(spermatia) growing at the ends of short
pedicels, from which they are ultimately
detached, like the spores of many Fungi ;

LICHENS.

[ 465 ]

LICHENS.

and, 3, pycnidia, in which are developed
stylospores like those of Fungi.

The commonest form of the apothecia is
that of sessile or stalked disks or cushions,
flat, convex, or hollowed into a cup (fig.
396) ; in other cases they are linear ; these
open forms characterize the formerly-called
Gymnocarpous Lichens. While in the
Angiocarpous genera the apothecia or rather
perithecia are closed globular receptacles or
conceptacles, analogous to those of the Sphce-
rice among the Fungi, and opening at the
summit to discharge the spores (fig. 395).
The apothecium may be composed of two
parts — the thalamium or hymeninm, and the
excipulum. The excipulum, when present,
sometimes forms a cup-like envelope derived
from the thallus, and of the same colour
(thalline), or it may differ in colour and
texture, in which case it is termed proper.
Or it may entirely or partly surround the
thalamium and thecee, and then forms the
perithecium. The thalamium is represented
by the body of the apothecium, open or
closed; and the layer of its cells immediately
lining the bottom of the cup, shield, or
conceptacle is sometimes called the hypo-
thecium, which bears the ihecce and the
paraphyses (fig. 398) ; the latter are filiform
or clavate cells (PI. 37. figs. 6 & 12), pro-
bably abortive thecas, among which they
are intermingled ; both these and the thecse
stand perpendicularly upon the hypothe-
cium, being surrounded by a gelatinous sub-
stance— the gelatina hymenea. The thecce
(PL 37. figs. 6 & 12) are usually ovoid or
elongated cells with thick walls, containing
the spores ; the thecas are shorter than the
paraphyses surrounding them; and the
whole are usually glued firmly together by
their contiguous lateral surfaces.

The spores consist of two layers, an epi-
sporeand anendospore; the former are tinged
blue with tincture of iodine, and present
many points of difference in different genera
and species. In Verrucaria muralis they
are ellipsoid, colourless, perfectly smooth
and semitransparent, containing granular
matter ; while in V. epidermidis and ato-
maria they are bilocular bodies, representing
a pair of obovoid cells adherent by their
thick ends. In their earlier stages of de-
velopment they appear solid ; subsequently
four nuclei or oily globules are seen in them,
each occupying a spherical cavity. The
membrane of the spore then becomes thin-
ner, and finally its two cavities coalesce into
one. When ripe, these spores are about

1-1500" in length and about 1-4000" broad.
There are eight in each theca, and they are
separately enveloped in a mucilaginous coat.
The spores are largest in the genus Pertu-
saria. Those of P. communis are visible to
the naked eye ; and observed in water soon
after emission from the thecae, they are not
less than 7-1000" to 8-1000" long by 5-1000"
broad. Their simple cavity is filled with
granular semitransparent matter, usually
with oil-globules of various sizes. The
epispore is very broad, transparent, and
formed of several lamellae ; these also are
coated with mucus. The genus Parmelia
(Physcid) offers both simple and bilocular
spores. Of the former, P. parietina gives
an example, though in some cases a trans-
verse partition is formed, and this is the
normal state in P. stellaris (PI. 37. figs. 6 &
7). In Peltigera (PI. 37. fig. 11) the spores
are elongated. In Cottema and other genera
the spores are divided into four chambers
by three transverse septa.

In several species of Lecanora, Lecidea^
Urceolaria, &c., a more complex form of
spore exists, longitudinal together with
transverse septa dividing the cavity into
several series of chambers. Those of Urceo-
laria (PL 37. fig. 17) have eight or ten
compartments ; those of Lecidea urceolata,
Thelotrema lepadina, Umbilicaria pustulata
(PL 37. fig. 18), and other Lichens, called
muriform spores, have a much larger num-
ber of little cavities, each containing a
distinct nucleus.

The emission of the ripe spores takes
place in the same way as in the Pezizce,
Helvellce, Sphcerice, and many other Fungi
of the same kind. If a portion of the
thallus, moistened, is placed in a common
phial, with the apothecia turned toward
one side, in about eight or ten hours the
surface of the glass opposite each apothe-
cium will be found covered with patches of
spores, easily perceptible by their colour,
these having been projected from the apo-
thecia with force. If placed on a moist
surface, and a slip of glass laid over them,
the latter will become covered with them
in the same way ; and Tulasne states that
they are projected to a distance of more
than half an inch from the theciferous layer,
the spores being emitted continuously for a
long time. The experiment may be tried
either in winter or summer, and has been
made with success on several common spe-
cies of Parmelia, Lecanora, Peltigera, Col-
lema, Borrera ciliaris, Verrucaria muralis ,

2H

LICHENS.

[ 4C6 ]

LICHENS.

Endocarpon hepaticum, Pertusaria, Urceo-
laria, Opegrapha, &c.

Eight is generally set down as the normal
number of spores in each theca ; but this is
not universal here any more than in the
Ascomycetous Fungi ; some species of En-
docarp<m, Parmelia, &c. have polysporous
thecae containing a considerable number,
while there are often less than eight.

Spermogonia. The Lichens exhibit another
form of reproductive organs, which are
liable to be confounded with Sphceronemei
and other Fungi growing on the Lichens,
or with parasitical Lichens in similar po-
sitions. They form black or brown points,
usually near the margins of the thallus
(PL 37. fig. 1), and have been found in
Borrera, Parmelia, Sticta, Cladonia, Collema,
Opegrapha, Spheerophoron, Lichina, JEndo-
carpon, &c., and seem to be universal.

The spermogonia are hollow pustules (PL
37. figs. 3 & 13) filled with filaments (sperma-
tophores, PL 37. fig. 3) producing extremely
minute bacilliform corpuscles (usually sper-
matid). They are immersed in the sub-
stance of the thallus (PL 37. figs. 2 & 13),
and are perceptible externally only by a
little projection, if at all; in rare cases they
are free and borne above the thallus (some
Cladonits, Cetrarice, Gyalecta, &c.). Their
ordinary form is globular, ellipsoidal, or
irregularly oblong, sometimes sinuous.
They have either a simple undivided cavity
(PL 37. figs. 13 & 16), or are multilocular,
divided in different ways into a variable
number of separate chambers or narrow
cavities, communicating with a common
orifice, the ostiole or pore of the apparatus.
This structure bears a close relation to that
usual in the Coniomycetous Fungi Cytispora,
Septoria, &c., and bears testimony to the close
connexion between the Lichens and Fungi.
The spermatia are regarded as analogous to
the spermatozoids in the antheridia of the
higher Cryptogams.

Pycnidia and Stylospores. Pycnidia are
dark-coloured conceptacles, found on Le-
cidea and Scutida, resembling the perithecia
of the Spheeriee, sessile on the thallus, and con-
taining simple filaments (basidia), bearing-
isolated spores on their apices (stylospores\

The so-called spermogonia and pycnidia
appear to be in some cases parasitic Fungi.

Chemical reagents are useful in the dis-
crimination of Lichens. Thus, iodine so-
lution will tinge the mature spores or the
gelatina hymenea of some Lichens blue, or
red without a preparatory blue tinge. So-

lution of caustic potash produces in the
thallu'? of some Lichens a persistent yellow
colour, which in others changes to a red ; or
if no reaction takes place, solution of chloride
of lime produces a red or yellow colour.
These reactions must be observed in sections.

The long-known resemblance of the
gonidia of Lichens to numerous forms of
the lower Algae, and the similarity of the
thecse of Lichens to the asci of Aseomy-
cetous Fungi, has of late years given rise
to the theory (Schwendener's) that the
gonidia of Lichens are really Algse ; the
Lichens being Ascomycetous Fungi, living
and growing upon them as parasites. The
Algae which, according to this view, form
the gonidia, are usually species of Palmella,
Protococcus, Nostoc, &c., rarely of Confer -
vaceae ; and when free, continue to grow
and reproduce, still retaining the Alga-
form. But when the germinating spores of
Lichens come into contact with them, the
hyphae surround the cells, enveloping them,
and on further growth a perfect Lichen is
formed. This question cannot at present
be considered as settled ; for while, accord-
ing to Bornet, the hyphae never produce
gonidia, according to Muller this occurrence
most positively does take place. On the
whole, it appears that Schwendener's in-
genious Lichen-theory will have to be
considered one of the modern natural-his-
tory romances.

The Lichens are divided into four families :

BYSSACEI. Thallus byssaceous or finely
filamentous, the granula gonima in a thai-
line sheath.

COLLEMACEI. Thallus gelatinous.

MYRANGIACEI. Thalamium with cellu-
lar cavities, and superimposed theciferous
cavities.

LICHENACEI. Thallus not gelatinous ;
variable in colour and form, either filamen-
tous, foliaceous, squamous, or crustaceous j
gonidial layer usually distinct.

BIBL. Tulasne, Ann. Sc. Nat. 3 ser. xvii.,
& Compt. rend. 1851 ; Montagne, Diet, d'hist.
nat. 1846 ; Itzigsohn, Bot. Zeit. viii. & ix. ;
Flotow, Flora and Bot. Zeit.', Lindsay, Pop.
Lichens ; Famnitzin and Boranetzky, Ann.
Sci. Nat. se'r. 5, viii. ; Leighton, Brit. Lich.
Flora ; Henfrey-Masters, Bot. ; Ny lander,
Lichenogr.,Europ., & Flora, 1879 (Jn. Mic.
Soc. 1880, 315, colour} ; Reess, Monatsb. fieri.
Ak. 1871 ; Bornet, An. Sc. N. 1873, xvii. ;
Schwendener, NageWs wiss. Bot. 1860, '62,
'68, SiAlgentyp. Flecht. Gonid., 1869; Archer,
Jn. Mic. Soc. xiii., xiv (all the papers on

LICHINA.

C 467 ]

LIGAMENTS.

Schio. Lich.-theory from 1868 to 1873); Vines,
Qu. Mic. Jn. 1878, xviii. 144, 438, later
papers on the same ; Thwaites, Ann. N. H.
1877, xx. 386; Frank, Krust. Fkcht., Cohn's
Beit. ii. 123; Stahl, Entw. d. Flecht. 1878;
Minks, Flora, 1878, Grevillea, 1879, vii.
89, & Grenz. zw. Fl. & Pike, 1881 ; Miil-
ler, Ann. N. H. 1881, viii. 427, & Grevillea,
x. 87 (Phillips) ; Crombie, Grevillea, vii.
143 ; Cooke, ibid. vii. 102, 117.

LIOHI'NA, Ag. — A genus of Collema-
ceous Lichens, allied to COLLEMA and
EPHEBE in many respects, formerly in-
cluded among the Algee on account of their
growing on the sea-shore (near high-water
mark), but having the thallus of a lichen
and bearing true apothecia and spermogonia.
The globose apothecia occur at the ends of
the branches of the thallus ; in L. pyymaa
the spermogonia occur underneath the apo-
thecia, in L. confinis at the apices of the
branches and often on the apothecia. The
spores, 8, simple, appear generally to adhere
to the walls of the thecse, which break up.
Sperniatia oblong.

BIBL. Greville, Alg. Brit. pi. 6 ; Leigh-
ton, Br. Lich. Fl 11.

LICMO'PHORA, Ag.— A genus of Dia-
tomaceae.

Char. Frustules in front view cuneate,
elongate, radiating in a fan-shaped manner
from a branched stipes ; side view (valves)
convex, inflected at the larger end and fur-
nished with transverse striae (rows of dots).
Marine.

L. jlabellata, S. (radians, K.) (PI. 17. fig.
3).

The species (one other British, Sm., five
in all, Kiitz.) are doubtfully distinct.

BIBL. Br. Diat.i. 85; Kiitz. Bacill 123,
and Sp. Alg. 113.

LICNO'PHORA, Cl.— A genus of Peri-
trichous Infusoria; resembling Trichodina,
but the anterior portion obliquely flattened,
and partly involute. Two species, on
Doris, marine Planarice, &c. (Kent, Inf.
651 ; Clap. Ann. So. N. 1867, viii.)

LIEBERKUH'NIA, 01. & Lachm.— A
genus of Reticularian Rhizopoda. Oviform,
with very thin test ; nucleus and contractile
vesicle unknown ; vacuoles present ; pseudo-
podia very long and reticular, branching
from a single stem, which is coated with an
extension of the filmy sarcode covering the
surface. 1 species ; fresh water at Berlin,
sea-water at Tenby.

BIBL. Clap. & Lachm. Etudes, 465 ; Sid-
dall, Qu. Mic. Jn. 1880, 141.

LIEBERKUHN. INTROD., p. xxi.

LIGAMENTS and TENDONS.— With the
exception of the elastic ligaments, which
are noticed under that head, the structure
of ligaments and tendons is essentially the
same. They consist of fibrillar connective
tissue, with a small quantity of elastic

Fig. 399.

Magnified 60 diameters.

Transverse section of the tendon of the tibialig posti-
cus ; human : a, secondary bundles ; 6, larger nuclear
fibres ; c, interstitial areolar tissue.

Fig. 400.

Magnified 20 diameters.

Transverse section of a tendon of a calf: a, secondary,
b, tertiary bundles ; c, nuclear fibres, obliquely divided ;
d, interstitial areolar tissue.

2n2

LIGAMENTS.

[ 468 ]

LIGAMENTS.

tissue. The fibres or fibrillai of the connec-
tive tissue are very minute, longitudinal,
parallel, closely connected, and pursue a
straight or undulatory course. Their union
into bundles is sometimes very indistinct,
and only to be shown by drying transverse
sections and afterwards treating them with
alkalies. In other instances the bundles
easily recognizable, of a polygonal,

are

rounded or elongated form (fig. 400), and
connected by loose interstitial areolar tis-

sue.

The elastic tissue of tendons exists as
slender nuclear fibres, sometimes forming
rows of narrow spindle-shaped cells con-
nected by slender processes, at others uni-
form fibres, or isolated spindle-shaped cells.
These are placed at regular distances apart,
between the bundles of areolar tissue.

When tendons are in contact with bones,
they frequently contain cartilage-cells, either
isolated or arranged in rows (fig. 401, c) ;
these sometimes undergo ossification.

The aponeuroses, fascije, and tendinous

Fig. 401.

,.J3

Magnified 300 diameters.

Portion of the tendo Achillis attached to the os calcis ; human: A, bone with lacunae a, medullary and fat-cells b ;
13, tendon with flbrillaj and cartilage-cells c.

sheaths consist of the same elements, but
in various proportions and differently ar-
ranged according to their functions, — some-
times the areolar fibres being predominant,
the structure agreeing with that of tendon,
whilst at others the elastic tissue is greatly
developed (fig. 403). Some of these tissues
also contain cartilage-cells.

The intervertebral ligaments consist of
fibro-cartilage, surrounded by osseous tissue ;
the centre is soft and containing concentric
cartilage-corpuscles (fig. 101, p. 135).

Magnified 350 diameters.

Cartilage-cells from the membranous ligament sur-
rounding the popliteua muscle : a, cell with one nucleus ;
6, cell with two nuclei ; c, cell containing one, d, two
secondary cells, the contents of both of which are more
consistent.

LIGNINE.

LIME

Magnified 450 diameters.
Elastic fibres from the inner part of the fascia lata, human ; densely interwoven and forming an elastic membrane.

BIBL. Kolliker, Mik. An. i. ; Henle, All-
gem. An. ; Bonders, Mulder's Phys. Chem. ;
Frey, Hist. 240.

LIGNINE. — A modified condition of
cellulose is obtained from old wood-cells,
and called by this name. It differs in its
reactions from pure cellulose, being coloured
yellow by sulphuric acid and iodine; but
after boiling in nitric acid and washing,
tincture of iodine and water give it a blue
colour. See SECONDARY DEPOSITS.

UMBORHLE.— A family of Angiocar-
pous or closed-fruited Lichens characterized
by rounded apothecia closed in by a carbo-
naceous special perithecium, finally bursting
in various ways, containing a somewhat
waxy nucleus, which grows hard.

British genera : Pyrenothea, Strigida.

LIME, SALTS OF.

Carbonate of lime. This substance is well
known as forming chalk, marble, &c., and as
occurring in hard animal structures, as bone,
shell, &c. It is not unf requently met with
in the form of granules as a component of
various animal secretions, as the urine, &c.
In this liquid, it sometimes, but rarely, also
occurs in little spheres or disks, consisting
of groups of radiating needles. This we
first found to be the case in human urine
(PI. 13. fig. 8); but it was subsequently
detected in that of herbivorous animals, as
the cow and the horse (PI. 13. fig. 7), in
which its occurrence is common. It is also

a component of otolithes, in which it exists
either as granules or minute prisms, often
with six sides and trilateral summits. From
river- and spring-water it is usually deposited
in irregular and imperfect forms (PI. 13.
fig. 6), all of which consist of grouped nee-
dles. Sometimes it assumes the rhombohe-
dral form, as in the shell of the oyster (PI. 45.
fig. 10) and frequently in ch.emica.1 solutions.
When treated with a dilute acid, after having
been thoroughly washed in a watch-glass,
it is dissolved with effervescence from the
escape of carbonic acid gas. During the
solution it first becomes more transparent,
exhibiting the internal crystalline structure,
and frequently a concentric or nuclear ap-
pearance, which finally disappears. When
derived from animal secretion^, it leaves
undissolved an organic cast of the original,
provided the acid be not too strong, or its
action too long continued. If the number
and size of the minute bodies be relatively
very small in nroportion to the amount of
water, on adding the acid, effervescence
will not occur, the water holding in solution
the carbonic acid evolved. The presence
of the lime may be tested in the ordinary
way, by the addition of oxalate of ammonia,
when the precipitate is insoluble in acetic
acid, or by adding dilute sulphuric acid,
when crystalline needles of the sulphate of
lime (PI. 10. fig. 16) are formed.

The spheres or disks naturally occurring

LIME.

[ 470 ]

LIMNIAS.

in the urine, are closely imitated by those
formed in urinelo which chloride of calcium
has been added, and which has been subse-
quently kept for some time.

Lactate of lime may be obtained by acting
upon carbonate of lime with lactic acid. It
is soluble in water and alcohol. The mi-
croscopic crystals consist of tufts of delicate
radiating needles (PL 11. fig. 19).

Oxalate of lime. This salt exists in solu-
tion in the contents of many vegetable cells
combined with a proteine compound ; it is
also probably a normal constituent of the
human blood in small quantity, combined
and dissolved as in vegetables.

In the cells of plants it is very frequently
deposited hi a crystalline form, constituting
RAPHIDES. From human blood it has been
obtained in crystals by treating the alcoholic
extract with acetic acid. It is very commonly
met with in the crystalline form in various
secretions of animals, as the urine, the mucus
of the gall-bladder, that of the surface of the
pregnant uterus, the liquid of the allantois,
the contents of the Malpighian vessels and
the so-called true renal vessels of insects,
cysts, &c.

Its most characteristic form is the square
flattened octahedron (PI. 13. fig. 9) ; but it
also occurs in the form of the square prism
terminated by quadrilateral pyramids, of fine
needles, and in that of a flattened body with
an ellipsoidal outline, frequently constricted
so as to resemble a dumbbell, or variously
excavated at parts of the surface (PL 13.
figs. 11 & 12). It may be obtained artificially
in most of these forms (PL 13. fig. 13), by
dissolving artificial oxalate of lime in dilute
nitric acid and evaporating ; some of the
forms thus obtained resemble those of car-
bonate of lime. When obtained by mixing
oxalate of ammonia with soluble salts of
lime, as chloride of calcium, &c., the crystals
are generally peculiar ( PL 13. fig. 14), al-
though sometimes the regular octahedra
are obtained.

It is insoluble in hot and cold water,
acetic acid and ammonia, but is soluble in
dilute mineral acids without effervescence.

Phosphate of lime. This salt is most fre-
quently deposited from animal liquids in
an amorphous or granular state. It may be
obtained in the crystalline form by mixing a
solution of phosphate of soda with chloride
of calcium. The crystals are mostly thin
rhombic plates (PL 10. fig. 17).

They are soluble in acetic and dilute
mineral acids without effervescence, but not

in potash or water. Some of the compound
crystals resemble those of the aminouio-
phosphate of magnesia, from which they
may be distinguished by the addition of
dilute sulphuric acid, which causes the for-
mation of needles of sulphate of lime.

Sulphate of lime. Well known as form-
ing gypsum, alabaster, selenite, &c. It rarely
or never occurs in the crystalline form in
animal or vegetable products. When rapidly
formed in chemical testing, the crystals
consist of minute needles or prisms (PL 10.
fig. 16) j when more slowly formed, these
are larger and mixed with rhombic plates.

The crystals are but little soluble in water,
and not in acetic or the dilute mineral acids.
They are sometimes found in bottles con-
taining spirit in which marine animals have
been preserved.

Medicinal precipitated sulphur is very
commonly adulterated with sulphate of lime.
The microscope at once enables the crystals
of the salt to be recognized.

Urate of lime. See URATES.

See EAPHIDES and URINARY DEPOSITS.

BIBL. That of CHEMISTRY, ANIMAL.

LIMNAC'TIS, Ktz.— A genus of Rivu-
lariacese, Confervoid Algae.

Char. Filaments pseudo-ramose, subfas-
ciculate, sheath more or less distinct. L.
panmla ; Lincolnshire.

BIBL. Rabenh. Fl. Alg. ii. 210.

LIMNADEL'LA, Girard.— A bivalve
Phyllopodous Entomostracon, near Es-
theria.

BIBL. Girard, Proc. Phil. Ac. i. 184, &
vii. 34 ; Grube, Wiegm. Arch. 1865, 73.

LIMNADIA, Brongn. — An aquatic bi-
valved Phyllopod, with thin oval valves,
enclosing an elongated body, having a short
and a natatory pair of antennae, oral appa-
ratus, twenty-two or more pairs of branchial
lamellae, and a bifid tail.

BIBL. Brongniart, Mem. Mus. Hist. Nat.
vi. pi. 13 ; Desinarest, Crust. 378 ; Milne-
Edwards, Hist. Nat. Crust, pi. 35. f. 7;
Baird, Zool Proc. 1849, 86, pi. 11. f. 1 ;
Grube, Wiegm. Arch. 1865, 61, pi. 8 ; Lere-
boullet, Ann. Sc. Nat. Zool. 5, v. 283, pi. 12.

LIMNE'TIS, Lov^n.— An aquatic bi-
valved Phyllopod, related to Limnadia and
Estheria.

BIBL. LovSn, K. V. Ak. Handl. 1845,
203; Baird, Zool. Proc. 1862; Grube,
Wiegm. Arch. 1865, 71.

LIMNIAS, Schrank.— A genus of Rota-
toria, of the family Floscularieea.

Char, Eyes (when young) two, red ; ur-

LD1NICYTIIERE.

[ 471 ]

LINGULINA.

ceoli or sheaths single ; rotatory organ with
two lobes. Teeth forming a row in each jaw.

L. ceratophylli (PI. 43. fig. 45). Urceolus
at first whitish, subsequently becoming
brown or blackish, smooth, or in conse-
quence of its viscidity covered with foreign
bodies. Freshwater ; length 1-24 to 1-18".

BIBL. Ehr. In/us. 401.

LIMNICYTHE'RE, Brady.— An Ostra-
code, allied to Cythere, the antennae having
setge instead of spines, and the valves being
hin, and spinous or tubercled.

BIBL. G. S. Brady, Linn. Tr. xxvi. 419.

LIMNOCH'ARES, Latr.— A genus of
Hydrachnea (Acarina),

C. aquatica (Jiolosericea) (PI. 6. fig. 27),
the only species. It differs from other
water-spiders by its walking instead of
swimming.

Body very soft and often spontaneously
variable in form; epidermis covered with
little conical granules (?) ; no hairs upon the
body, and but few upon the legs ; eyes at-
tached to a lanceolate scaly piece (d), and
surrounded by hairs; rostrum partly con-
cealed beneath the skin, the anterior ex-
serted half (b) cylindrical and accompanied
by the palps, the last joint of which is very
slender and obtuse ; by pressure the broader
base of the rostrum is made to protrude (/);
tarsi (c) thickened at the end, with Jarge
claws ; coxa3 of four posterior pairs of legs
longer than the others, which is contrary to
what occurs in Hydrachna, Atax, &c. ; coxae
of the two anterior pairs of legs closely
approximate, as are also those of the two
posterior pairs (e) ; but the two groups are
widely separated.

Larvae with six legs, a large head-like
rostrum, with two large palps and two black
lateral anterior eyes, fixing themselves on
the head of Gerris lacustris ; they subse-
quently detach themselves, fall into the
water, and pass their nymph-stage under
submersed stones, the perfect animal making
its appearance at the end of fifteen days.

BIBL. Duges, Ann. Sc. Nat. 2 eer. i.
159 ; Gervais, Walckenaer 's Arachn. 208 ;
Koch, Deuts. Crust etc.

LIMNODIC'TYON, Kiitz.— A genus of
Protococcacese.

Char. Cells angular from mutual pres-
sure, forming membranous layers, in a
parenchymatous form; multiplication by
gonidia.

L. Rocmerianum (PI. 52. fig. 14), in
pools.

BIBL. Rabenh. Fl Alg. iii. 61.

LIMNO'RIA, Leach. — A genus of ma-
rine Crustacea, Order Jsopoda, and family
Asellota.

L. terebrans (PL 36. fig. 27) is of interest
on account of the great ravages which it
commits in submerged timber, as the piles
of piers, flood-gates, docks, &c., which it
perforates in every direction. Head large,
rounded; antennas four, of nearly equal
length ; eyes two, lateral, black, composed
of about seven ocelli ; body elongato-sub-
cylindrical, thorax with seven joints, legs
seven pairs, formed for walking ; abdomen
six-jointed, the last joint large, suborbi-
cular, and with two styles ; length about
1-6". It contracts into a ball when dis-
turbed.

BIBL. Leach, Linn. Tr. xi. 370 ; Cold-
stream, Edin. New Phil. Jn. 1834 ; Dalyell,
Wonders of Creation, i.

L1NDIA, Duj. — A genus of Rotatoria, of
the farnilv Hydatiusea, E. (Furcularina,
Duj.).

Char. Body oblong, almost vermiform,
with transverse folds, rounded in front, but
no rotatory organ, cilia, or eye ; tail-like
foot with two conical and short segments
or toes ; jaws very complicated (and im-
perfectly described).

L. tondosa (PI. 43. fig. 40). Freshwater ;
length 1-75".

BIBL. Duj. In/us. 653; Cohn, Sieb. $
Roll. Zeit. 1858, 286 ; Pritch. In/us.

LINDS^EA, Dryander. — A genus of
Lindsayese (Polypodiaceous Ferns). Exotic
(fig. 404).

Lindsaea.
A pinnule. Magn. 10 diams.

LINGULl'NA, D'Orb.— A hyaline sti-
chostegian Foraminifer, differing from No-

LINGULINOPSIS.

[ 472 ]

LITOSIPHON.

dosaria in being laterally compressed and
having a slit-like aperture.

BIBL. Carpenter, Introd. 163.

LINGULINOPSIS, Reuss.— This may
be denned as a Lingulina having its early
chambers coiled ; or a Maryinulina much
compressed and opening with a rift.

BIBL. Reuss, K. bohm. Oes. Wiss. 1860.

LINOP'ODES, Koch.— A genus of Trom-
bidina (Acarina); with the legs 6-jointed,
the anterior pair very long and slender.
Three species j among moss j red or orange.
(Murray, EC. Ent. 122 ; Hermann, Apter.)

LI'NUM, L. See FLAX.

LIOSI'PHON, Ehr.— A genus of Holo-
trichous Infusoria, fain. Trachelina.

Char. Resembles Nassula, but the frontal
region prolonged. 1 species.

BIBL. Pritchard, In/us, p. 627.

LIOSTEPHA'NIA, Ehr.— A genus of
Melosireae (Diatomaceae).

Char. Frustules single, orbicular; disk
smooth, but with a crown of rays round a
smooth space ; 3 species ; Barbadoes.

L. rotula (PI. 51. fig. 17).

BIBL. Pritchard, Infus. p. 813.

LIOTHE'UM, Nitzsch.— A genus of
Anoplura, family Liotheidae.

Char. Antennae clavate or capitate j max-
illary palpi conspicuous ; mouth with strong
mandibles ; tarsi with two claws.

Antennae four-jointed; mandibles with
two teeth; maxillary palpi long, filiform,
four-jointed ; labial palpi very short, two-
jointed.

The genus has been subdivided into seven
subgenera. The species are very numerous,
and are parasitic upon birds.

L. (Menopori) pallidum (PL 35. fig. 7).
Elongate, of a pale straw-colour, shining and
smooth ; head slightly sinuate on each side,
with a dark pitchy spot before each eye.
Length 1-24 to 1-16". Common on the
domestic fowl. Other species on the par-
tridge, pheasant, and quail.

BIBL. Denny, Monogr. Anoplur. p. 204.

LIPAROGY'RA, Ehr.— A genus of
Melosireae (Diatomaceae).

Char. Frustules simple, cylindrical, each
having an internal spiral filiform band or
crest.

BIBL. Pritchard, Infus. p. 823.

LIPEU'RUS, Nitzsch.— A subgenus of
Philopterus. The species are found on the
pigeon, the goose, the fowl, and the turkey.

BLBL. Macalister, Qu. Micr. Jn. 1871,
163 ; Murray, EC. Ent. 381; M<%nin; Paras.
88.

LIR ADIS'CUS, Grev.— A genus of Dia-
tomaceae.

3 species; Barbadoes deposit. L. Bar-
badensis (PI. 52. fig. 13).

BIBL. Greville, TV. Mic. Soc. 1865.

LISTROPH 'ORUS, Pagenst.— A genus
of Acarina, allied to Scarcoptes. Two spe-
cies, on field-mice, rabbits, and the ferret,
the partridge, &c. The maxillae form two
flexible claspers, for clinging to the hairs.
(Pagenstecher, Zeits. wiss. Zool. xi. 156;
Murray, Econ. Ent. 324.)

LITHIC ACID. See URIC ACID.

LITHOCYS'TIS, Allm.— A genus of
Corallinaceae (Florideous Algae), consisting
of a single species, L. AUmanni, Hass., which
has been found as an epiphyte, forming
minute white dots upon Chrysimenia clavel-
losa. The minute dots consist of one or
more fan-shaped fronds composed of square
cells. The plant is colourless, brittle, and
effervesces in acid. The fan-shaped frond
somewhat resembles in structure imperfect
or segmental fronds of COLEOCHJETE.

BIBL. Harvey, Mar. Alg. Ill, pi. 14 B ;
Phyc. Brit. pi. 166.

LITHODES'MIUM, Ehr.— A doubtful
genus of Diatomaceae. Marine.

L. undulatum (PI. 17. fig. 4 a, front view ;
4 b) side view). Surface without marking?,
very pellucid, two of the sides undulate, the
third plane and with two marginal notches ;
angles obtuse ; length of joints 1-480".

BIBL. Ehr. Abh. d. Berl Akad. 1840;
Kiitz. Bacitt. p. 135, and Sp. Ala. p. 133.

L1THOFELLINIC ACID.— Is a com-
ponent of certain concretions called bezoars,
found in the alimentary canal of various
kinds of goat in Persia &c.

It is crystalline, insoluble in water, readily
so in hot alcohol, but little in ether.

The perfect crystals form six-sided prisms
with truncated ends ; but when somewhat
rapidly deposited from an alcoholic solution,
they are modified as represented in PL 11.
fig. 14. With Pettenkofer's test they are
turned red.

LITHOG'RAPHA, NyL— A genus of
Graphidei (Lichenaceous Lichens).

Char. Thallus crustaceous or evanescent;
apothecia lirelleeform, black, tumid ; epi-
thecium rimiform, margins thick, convex ;
hypothecium black, thick, entire ; spores 8
or numerous, simple or 1 -septate.

7 British species. Rare.

BIBL. Leiphton, Brit. Lich. Flor. p. 393.

LITOSI'PHON, Harv. — A genus of
Pimctariaceee (Fucoid Algae), with fronds

LITUOLA.

[ 478 ]

LIVER.

composed of cartilaginous filiform un-
branched filaments, at first solid, afterwards
tubular, composed of several rows of cells ;
epiphytic on Chorda filum (L. putttkts) and
Alaria (L. Laminarice] , the former 2 to 6"
long, the latter 1-4 to 1-2". The sporanges
occur either solitary or aggregated, scattered
on the surface of the filaments, which in
L. pusillus are clothed with pellucid hairs,
in L. Laminari(S smooth.

BIBL. Harv. Mar. Ala. p. 43, pi. 8 D ;
Thuret, Ann. Sc. Nat. 4 ser. iii. p. 14.

LITU'OLA, Lamarck. — A protean Fora-
miniferal genus, abundant both recent and
fossil; characterized by the test being coarsely
arenaceous, with little or no calcareous
cement. The shell may be unilocular (Pro-
teonina?, Williamson). If compound, its
shape may be loosely moniliform (Reophax,
Montfort), whether straight, coiled, or
irregular, free or attached (the latter
feature characterizing Placopsiiina, D'Orb.).
Or the chambers may be close-set and
overlapping, and have either a straight,
coiled, or crozier-like contour, imitating
various forms of other Foraminifera, such
as Orthocerina,Nodo8aria,Flabellina, Cristel-
laria, Spirolina, JRotalia, Nonionina, Globi-
aerina, Orbulina, &c. Further, the chambers
may communicate by a simple central
aperture, or by a cribriform septal plate;
and they may be either simply hollow, or
labyrinthic from secondary growths. Some
with a single aperture and undivided
chambers, and some which are labyrinthic
&nd cribriform, belong to Reuss's Haplo-
phragmium and Haplostiche (straight).
When the aperture is of a horse-shoe shape
and subvalvate, we have the allied Hippo-
o-epina, Parker. PI. 23. fig. 18 is an irre-
gularly nautiloid, labyrinthic form (Lituola
difformis) very common in the Chalk.

BILL. Carpenter, Introd. p. 143.

LITUO'LIDA, Carp. = LITUOLID^E and
ASTRORHIZID^;, p. 332. — Besides the
coarse-grained genus Lituola (with its sub-
divisions), there are several closely related
forms which differ chiefly in the degrees of
smoothness and compactness with which
the constituent sand-grains, and sometimes
spicula, are set and cemented.

JBotellina, Carpenter, is a long, roughly
segmented tube of sand and spicules, with
ill-defined terminal aperture. Saccammina,
Sars, is spherical and smooth, either single
or in twos or threes united by a narrow
stolon-tube. This is found fossil in the
Lower Carboniferous strata, as well as

recent. Pilulma, Carpenter, quite spherical,
with a fissure-like mouth, is composed of
very fine sand and points of spicules. As-
irorhiza, Sandahl, relatively large, has a
coarse, irregularly stellate, test of loosely
aggregated sand, with pseudopodial aper-
tures among the granules, chiefly at the
ends of the digitate radii. Hhadammina,
Sars, arenaceous, with a cement containing
ferric phosphate, is tubular, forked, cr
radiate, usually trifid, with a central cavity;
openings at the radial ends.

The Lituolida with fine-grained and smooth
tests are best typified by Trochammina and
its subgenus Webbina (D'Orb., restricted).
These range from simple, attached, tent-like,
single or multiple tests (W. hemispJxerica,
W. irreaularis, &c. ), to the tubular and spiral
Troch.incerta(Pl. 23. fig. 14) andtherotalioid
T. squamata et inftata. The rotalioid and
fusuline Endothryce and the nummulitoid
Involutina, all fossil, belong to the same
category.

Valvulina, one of the TEXTULARIID^;,
sometimes finely, sometimes coarsely arena-
ceous, is, in this character, allied to the
Lituolines and Trochammines ; and among
its several modifications some link it with
Lituola and others with Trochammina.
Tetrataxis has an alternation of four, and
Valvulina (PI. 23. fig. 20) of three chambers.

The Lituolida are represented in every
existing sea, and in every geological forma-
tion as far back as the Carboniferous.

BIBL. Carp. Introd. 140 ; Descr. Cat. Mic.
Soc. April 1870, 4 ; Parker, Jones, and
Brady, Phil. Tr. civ. 406; Monogr. Crag
For., Pal. Soc. 25 ; Brady, Mm. Carl. For.,
Pal Soc. 1876 ; Qu. Mic. Jn. n. s. xxi.

LIVER. — The glandular organ which
secretes the bile.

On examining the surface or a transverse
section of the liver with the naked eye, it
usually presents a mottled appearance,
numerous spots of a dark or light red
colour being surrounded by a margin of a
paler or darker colour. These spots cor-
respond to the lobules of the liver.

The lobules are rounded or polygonal, and
about 1-2 to 1'" in diameter (fig. 405).

Between the lobules run branches of the
vena portse, forming the interlobular veins
(coloured red in PI. 39. fig. 33) ; these
throughout their course send off numerous
smaller branches into the substance of the
lobules, which terminate in the capillary
plexus of the lobules.

The branches of the vena portaa are accom-

[ 474 ]

Magnified about 3 diameters.

Portion of the liver of a pig, with divided branches of
the vena cava ; the lobules are visible upon the divided
surfaces : a, large vein, no oriilces of the intralobular
veins being visible ; b, branches of the same, with dis-
tinct orifices of the intralobular veins, and the bases of
the lobules seen through their walls.

panied by branches of the hepatic duct and
ramifications of the hepatic artery, the whole
being surrounded by connective tissue pro-
longed from Glisson's capsule. Hence, in
a section of the uninjected liver,
those branches of the vena portse
and of the vena cava which are
visible to the naked eye are readily
distinguishable from each other by
the orifices of the former collapsing,
whilst those of the latter are kept
open by their close contact with the
lobules.

In the centre of each lobule arises
a branch of the vena cava, by the
union of numerous smaller branches
(coloured yellow in PI. 39. fig. 33),
which take their origin in the ca-
pillary plexus of the lobule j these
central branches form the intralobu-
lar veins.

The capillaries of the lobules form
a close and elegant plexus between
the branches of the inter- and intra-
lobular veins, the rest of the lobules
being filled up with the secreting
cells.

Magnified about 4 diameters.

Section of the liver of a pig through a branch of the
vena portse, with accompanying branches of the hepatic
artery and duct. On the right are seen two branches
of the vena portae giving off the interlobular veina.

The branches of the biliary ducts accom-
pany those of the vena portsB as far as the
interlobular spaces, where they again branch
off, forming a network of extremely slender
tubes or biliary capillaries, which surround
individually the liver-cells (fig. 408). The
biliary ducts consist of an outer coat of
connective tissue, the bundles of fibres of

Fig. 407.

Magnified 35 diameters.

Section of a portion of the liver of a rabbit, showing the entire
course of one of the intralobular veins, the roots only of the
others.

LIVER.

[ 475 ]

LIVER.

which are difficultly separable, and an in-
ternal epithelial layer. The former is most
distinct in the larger branches, being almost
absent in the terminal interlobular ducts ;
it contains numerous nuclei and nuclear
fibres. Kolatschewsky states that the bile-
ducts are directly continuous with the
cavity of the liver-cells. The epithelium

Fig. 408.

Magnified 200 diameters.

Biliary capillaries from the liver of the rabbit: o,
biliary capillaries ; 6, liver-cells ; c, bile-ducts ; d, ca-
pillary blood-vessel.

of the larger ducts is cylindrical, that of
the smaller of the pavement kind. In the
hepatic ducts, the outer coat contains scat-
tered muscular fibre-cells. The ducts also
contain small mucus-glands. The secreting
cells of the lobules fill up the interspaces
between the blood-vessels. They are very
transparent, of a rounded or polygonal form,
about 1-1000" in diameter, containing one
or two nuclei, with a very fine reticulum
and a number of granules, and a few small
globules of fat (fig. 160, page 238).

Kupffer describes star-cells existing with-
in the liver-cells, after staining with chlo-
ride of gold.

The division of the substance of the liver
into lobules is rather apparent than real,
being effected by the peculiar arrangement
of the vessels, the lobules having no true
coat or envelope.

The connective prolongation of Glisson's
capsule which accompanies the vena portse
and its branches becomes less and less in
quantity as the branches become smaller,
and is apparently lost in the interlobular
spaces. It is much more abundant in
animals, as the pig, than in man, rendering
the tabular arrangement much more dis-
tinct. But, after washing away the liver-
cells with a hair-pencil, from a thin section,
a very delicate network, consisting of a
homogeneous membrane with minute nu-

clei, remains, in the meshes of which the
liver-cells are placed.

The branches of the hepatic artery are
distributed to the portal vessels, the hepatic
ducts, Glisson's capsule with its prolonga-
tions, and the peritoneal coat. They are
often elegantly tortuous.

Among the more common morbid states
of the liver may be mentioned : — that called
cirrhosis, in which the connective tissue is
excessively developed and mixed with a
large number of fibro-plastic corpuscles,
producing an atrophied state of the epithe-
lial structure; the amyloid degeneration,
which commences between the inter- and
intra-lobular portions, in the branches of
the hepatic artery ; an increase in the
amount of fatty matter in the cells (fig. 160,
page 238) ; and the presence in these also
of granules of cholepyrrine, rarely with
crystals of cholesterine and bilifulvine.

The examination of the arrangement of
the blood-vessels is best made in a liver
which has been injected with two kinds of
injection, as yellow (chromate of lead) and
red (vermilion), or red and white (carbonate
of lead) — the yellow or white being injected
into the hepatic vein. As the injection is
being proceeded with, the surface of the
liver should be examined with a lens to
ascertain whether the intralobular veins are
well filled, and the injection has reached
the capillaries; the red injection should
then be thrown into the portal vein until
it is filled. The general vascular arrange-
ment is best observed in an injection in
which the capillaries themselves are not
filled, but only the smaller portal and he-
patic branches.

To examine the ducts as to their course
and termination, the portal vein should
previously be injected. If this be not done,
the injection easily bursts through the walls
of the terminal ducts, and escapes into the
intralobular plexus ; and thus the appear-
ance of a plexus of vessels prolonged from
the terminal ducts is produced. The fine
ferridcyanide cold injection should be used.

The structure of the hepatic cells is easily
seen on scraping the surface of a section of
the liver, and placing the portion thus ob-
tained between two pieces of glass as usual.

The minute structure of the liver is best
seen in sections of portions which have
been hardened in chromic acid or spirit,
and stained with logwood. In these, the
cut orifices of the biliary capillaries are
sometimes seen, between the liver-cells.

LLAVEA.

[ 476 ]

LOPHOPUS.

The general arrangement of the secreting
cells is observed in sections made with
Valentin's knife.

In many animals, as fishes, the loading
of the cells of the liver with fat, which in
man represents the morbid state of fatty
degeneration, is normal, and renders it a
matter of some difficulty to distinguish
clearly the outlines of the cells, which are
also very delicate.

BIBL. Kiernan, Phil. Tr. 1833 ; Kolliker,
Mik. Anat. ii. ; H. Jones, Phil. Tr. 1846,
and 1849; Guillot, Ann. Sc. Nat. 1848;
Leidy, Sill Jn. 1848 ; Beale, Liver, & How ;
Hering, StricJcer's Gewebel. i. 429 ; Kolats-
chewsky, Sch. Arch. 1877, xiii. 415 ; Frey,
Hist. 640.

LLA/VEA, Lagas.— A genus of Pteridese
(Polypodiaceous Ferns). One species ;
Mexico. (Hooker, Syn. Fil. 144.)

LOASA'CE^E.— A family of Dicotyledo-
nous Flowering plants, with stinging hairs
upon the epidermis. Loasa, Bartoma, and
Blumeribachia are often to be obtained in
gardens.

LOCUST-BEANS.— The seeds of Cera-
tonia siliqua are so called.

LOFTU'SIA, H. B. Brady.— A large fusi-
form arenaceous Foraminifer, consisting of
a spiral lamina, secondary oblique longitu-
dinal septa, and tertiary vertical divisions,
making the internal structure labyrinthic.
In texture similar to the higher Trocham-
rnince, Loftusia stands high amongst the
arenaceous forms, corresponding with Alveo-
lina in the Porcellaneous, and Fusidina in
the Hyaline group. Fossil in Persia.

BIBL. Brady, Phil Trans. 1869, 751.

LOMA'RIA, Willd.— A genus of Pteii-
dea3 (Polypodiaceous Ferns).

L. Spicant, often called Blechnum boreale,
is British. Many other foreign species.
(Hooker, Syn. 174.)

LONCHI'TIS, Presl.— A genus of Pteri-
dese (Polypodiaceous Ferns). Differs from
Pteris in the sori occupying the sinus ;
exotic (fig. 410). (Hook, Syn. 128).

Fig. 410.

Lonchitis pubescens. A pinnule with sori.
Magnified 10 diams.

LO'PHIUM, Fr.— A genus of Pyre-
nomycetes (Ascomycetous Fungi), remark-
ably distinguished by the form of the peri-
thecia resembling a bivalve shell with the
valves in situ (tigs. 411 & 412). The nu-
cleus contained within the carbonaceous

Fig. 411. Fig. 412.

Fig. 413.

Lophium mytilinuui.
Pig. 411. A perithecium, seen side wise.
Fig. 412. The same, seen endwise.
Pig. 413. A perithecium cut open.
Magn. 25 diams.

perithecium consists of erect asci mixed
with paraphyses, containing minute spores,
and soon falling away into a powder. L.
mytilinum, Pers. (figs. 411-13), occurs on
the bark or naked wood of fir trees. L.
elatum, Carm., also occurs on fir wood.

BIBL. Berk. Br. Fl ii. pt. 2. 280 ; Fries,
Syst. Myc. ii. 533 ; Summa Ve.g. 401 ; Gre-
ville, Sc. Crypt. Fl. pi. 177.

LOPHOCO'LEA, Neea.— A genus of
Jungermannieae (Hepaticse), including J.
bidentata, L., and J. lieterophylla, Schrad.,
growing in moist situations, at the roots of
trees, &c.

BIBL. Hook. Brit. Jungerm. pis. 30, 31
Br. Fl ii. pt. 1. 122.

LOPHO'MONAS, Stein.— A genus of
Flagellate Infusoria.

Char. Free, ovate, spherical or fusiform,
with an anterior tuft of long slender
flagella.

Two species; intestines of Blatta. &c.
(Kent, Inf. 321.)

LOPHOPH'ORUS, Br.— A genus of
Copepodous Entoinostraca.

L. insignis. In marine dredgiugs, Dur-
ham. (Brady, Copep.. Ray Soc. i. 121.)

LOPHOPO'DIUM, Ktz.-A doubtful
genus of Oscillatoriaceae, allied to Amphi-
thrix. 6 spec., on submerged stones and
posts.

BIBL. Rabenh. Fl. Eur, Alg. ii 231

LOPH'OPUS, Dumortier.— A genus of
freshwater Polyzoa, of the order Hippo-
crepia, and family Plumatellidae.

Char. Polypidom sacciform, hyaline, ge-
latinous, with a disk serving for attachment ;

LORICA.

[ 477 ]

LUNGS.

orifices scattered ; ova elliptical, with a
ring, but no spines.

BIBL. Allruan, Fresh. Polyzoa (Ray Soc.),
83; Johnston, Brit. Zooph. S9I.

LORI '0 A. See CARAPACE.

LOUSE. SeePEDicuLusandANOPLURA.

LOVEXEL'LA, Hincks.— A genus of
Campanulariidae (Hydroid Zoophytes).

Char. Sterns simple or slightly branching,
rooted by a thread-like stolon ; capsules
turbinate, elongate, operculum of distinct
segments ; proboscis large and prominent.
L. clausa, in dredginsrs, Torbay.

BIBL. Hincks, Brit Hyd. Zooph. 177.

LOXOCEPH'ALUS, Eberh.— A genus
of holotrichous Infusoria.

Char. Free, ovate-oblong, constricted
towards the front, with one or more short
setae at the constriction, and one or more
caudal setae.

Two species. Freshwater, with decaying
vegetation. (Kent, Inf. 488.)

LOXOCON'CHA, Sara.— A marine Os-
tracode, allied to Cythere, with long setife-
rous antennas, and strong subrhomboidal
valves, which have toothed hinges and often
a pitted surface. Common in the British
and other seas, and fossil in the Tertiary
and post-Tertiary strata.

BIBL. Brady, Linn. Tr. xxvi. 432.

LOXO'DES, Ehr.— A genus of hypo-
trichous Infusoria, family Trachelina.

Char. Body curved, with a longitudinal
row of transparent vesicles, each of which
contains a highly refracting body, and with
a more or less arborescent distribution of
the digestive canal.

L. rostrum, Ehr., Pelecida rostrum, Duj.
(PI. 31. fig. 39) ; freshwater.

L. bursaria (PI. 81. fig. 41) is a Parame-
cium. L. cucullulus and L. dentatus belong
to Chilodon.

BIBL. Ehr. Inf. 323 ; Duj, Inf. 449 ;
Stein, Inf. ; Claparede et Lach. Inf. 339.

LOXOPHYL'LUM, Duj.— A genus of
holotrichous Infusoria, fam. Trachelina.

Char. Body flat and leaf-like ; contractile
vesicle posterior, near the anus ; anterior
part of the body sometimes produced. 6
species. L.fasciola (PI. 30. fig. 10). They
belong to the genera Amphileptus and Tra-
chelius, Ehr.

BIBL. Duj. Infus. 487; Claparede et
Lachmann, Infus'. 360; Kent, Inf. 527.

LOXOSO'MA, Keferst — A genus of
Polyzoa, fam. Pedicellinidae. Like Pedi-
ce/lina, but united in colonies. 3 species,
on marine annelida. (Hincks, Polyz. 572.)

LOXSO'MA, Brown.— A genus of Hy-
menophylleaa (Polypodiaceous Ferns), dis-
tinguished by the projecting column bearing
the sporangia (figs. 414; 415, 416).

Fig. 414.

Fig. 415.

Loxsoma Cunninghamii.

Fig. 414. A pinnule with marginal sori. Magn. 5 diams.
Fig. 415. A sorus opened. Magn. 25 diama.
Fig. 416. Columella with sporanges. Magn. 50 diams.

New Zealand (Hooker, Syn. 56).

LUCERNARIA, Fabricius.— A genus of
Medusae. L. auricula is common in the
summer in the seas of England and Norway.
It can be kept for some time in an aqua-
rium, and from the small size of many indi-
viduals, is a very interesting object for the
microscope.

BIBL. M. -Edwards & Haime, Coraill. iii.
457; Agassiz, Sea-side Stud., 1871, 46 j
Keferstein, Zeit. f. wiss. Zool. xii.

LUMBRI'CUS. — A genus of setigerous
Annulata. L. ten-estris, the earthworm.
Ray Lankester, Qit. Mic. Jn. 1864 & 1865 ;
Lockhart Clarke, Proc. Roy. Soc. 1857, 344
(nervous system) ; Rolleston, Forms of An.
Life.

LUNGS. — The internal respiratory sacs
of animals.

Under this head we shall notice also the
larynx, trachea, and bronchi.

Larynx.— The cartilages of the larynx do

LUNGS.

[ 478 ]

LUNGS.

not all possess the same minute structure.
The thyroid and cricoid cartilages consist of
hyaline cartilage, the basis being homoge-
neous, and containing disseminated cartilage-
corpuscles. The walls of the corpuscles are
usually thick. The basis often becomes
fibrous, and both corpuscles and basis in-
crusted with calcareous salts, or completely
ossified. Their perichondrium is firm, and
is composed of connective tissue, with fine
elastic fibres, vessels, and nerves.

The epiglottis (PI. 49. fig. 40) and the
appendices of the arytenoid consist of fibro-
cartilage ; and the corpuscles are frequently
more or less filled up by secondary deposit.

The mucous membrane, as also the sub-
mucous tissue of the larynx, consists of
connective tissue with networks of fine
elastic fibres; at the surface it becomes
more homogeneous, but does not form a
separable basement layer or membrane. It
contains a number of small racemose glands,
the vesicles of which are lined with pave-
ment, the ducts with cylindrical epithelium.
Its surface is covered with ciliated epi-
thelium, agreeing in structure with that of
the trachea.

Trachea and larger bronchi. — The incom-
plete cartilaginous rings of these tubes are
surrounded and connected together by a
firm, elastic, fibrous membrane, forming
their perichondrium, which also covers the

Fig. 417.

Epithelial cells of the trachea in situ; human, a,
longitudinal elastic fibres ; 6, homogeneous outer (base-
ment) layer of the mucous membrane ; c, deep layers
of round cells ; d, intermediate layers : e, outer ciliated
cells.

Magn. 350 diameters.

posterior part of the tubes as a somewhat
thinner layer. The cartilage is of the true
kind. At the posterior part of the tubes is
a layer of unstriated muscular fibres, most
of which form transverse, but a few longi-

Fk. 418.

tudinal bundles. The elastic tissue of the
mucous membrane is greatly developed,
forming a distinct internal layer of princi-
pally longitudinal anastomosing fibres.

The epithelium is ciliated, and consists
of several layers. The deepest layers are
composed of roundish cells with distinct
nuclei, those succeeding being elongated,
while those next the surface are still longer,
greatly narrowed at the base, and with oval
nuclei. Those of the last row are covered
with vibratile cilia (fig. 418).

The smaller bronchi differ
in structure somewhat from
the larger. Thus, the car-
tilage forms angular plates
distributed throughout
their circumference, while
the elastic and connective-
tissue coats become thin-
ner, and the transverse mus-
cular fibres smaller and less
closely placed.

Air-cells. The terminal
bronchi open into a group f
of air-cells partly fused to-
gether, forming common
cavities — the lobules, al-
veoli, or infundibula. These
are separated from each
other by connective tissue
mixed with muscular
fibres, containing, in adult Isolated {fchelial

animals, black pigment m cells from the surface

the form of granules, some- °f the trachea ; hu-
times also crystals They ma^nifled 350 dia.
are best seen m the lungs meters,

of young animals.

The walls of the pulmonary air-cells
consist of a fibrous, and an epithelial layer.
The former is composed of a basis of homo-
geneous connective tissue, with numerous
elastic fibres, vessels and nerves.

The elastic fibres surround the air-cells
in the form of elegant wavy bundles and
separate fibres, which anastomose and con-
stitute a dense network, most obvious at
those parts where several cells are in con-
tact with each other ; while in other parts
the areolar element supporting the nume-
rous capillaries predominates, and the elastic
elements are more sparing and slender.
The epithelium is of the pavement kind,
not ciliated, consisting of rounded or polygo-
nal nucleated cells, about ??rW in diameter.

The smaller or primary lobules are ag-
gregated to form larger secondary lobules —
the lobules of descriptive anatomists, and

LUNGS.
Fig. 419.

[ 479 ]

LUNGS.

r

Two pulmonary lobnles a a, with the air-cells 6 b,
and the terminations of the bronchi c c ; from an infant
newly born.

Magnified 25 diameters.

the outlines of which in adults are also
principally mapped out by lines of pigment.

Fig. 420.

Outer surface of the lung of a cow, the air-cells, of
which are inj ected with wax : a, a, a, air-cells ; 6, b,
boundaries of the (primary) lobules.

Magnified 30 diameters.

The tabular structure of the lungs is best
shown in the lungs of foetal animals in-
jected from the trachea or bronchi.

The capillaries of the lungs are extremely
minute and very difficult to inject fully;
and the finest injection is required for the
purpose.

The capillaries may often be well seen
in thin sections of the inflated and dried
organs. The altered structure of eniphyse-

matous lungs may also be best shown by
this method.

Fig. 421.

Air-cells of a human lung, a, epithelium; 6, fibrous
portion, where the walls of several air-cells are con-
fluent ; c, thinner walls of several air-cells.
Magnified 350 diameters.

Fig. 422.

Capillaries of the human lung.
Magnified 60 diameters.

The epithelium is best seen in sections of

LUNULARIA.

[ 480 ]

LYCOPODIACEJE.

a lung which has been injected from the
trachea with a very weak solution of nitrate
of silver; or in well-washed sections treated
with very dilute acetic acid; solution of
logwood is useful for staining.

The lymphatics invest the subpleural
lobules in the form of a plexus, and dip
inwards to join the deep-seated tubes which
accompany the bronchi and large vessels to
the root of the lung.

In the lower vertebrate animals, the
structure of the lungs is much simplar than
in the higher. Thus in the Trit&n each
forms a simple tubular sac, whilst in the
frog and toad (PI. 39. fig. 34) each lung
may be compared to a single lobule of a
lung of the Mammalia, having a cavity in
the centre, with which comparatively few
large cells extending into the periphery
communicate. The capillaries are also much
larger, especially in the two animals last
mentioned.

BIBL. Kolliker, Mik. An. ii. ; Stannius,
Vergl. An. ; Waters, Human Lung, 1860 ;
Verson and Schulze, Strieker9^ Hist. i. ;
Williams, Todds Cycl. An. j Luschka, Ar-
chiv mik. Anat. v. 1 ; Frey, Hist., and the
Bibl.

LUNULA'RIA, Michel.— A genus of
Marchantiese, growing on the ground in
shady places, having the perigones spread-
ing like rays from the top of the receptacle
(tigs. 319, p. 387, 329-331, p. 389), which is
a mere peduncle, so that an approach is made
to the character of the Jungermanniese.
See HEPATIC^:.

LYCOG'ALA, Mich.— A genus of Myxo-
mycetes, consisting of somewhat globular
bodies, verrucose on the outside, composed

Fig. 422*.

Lycogala epidendrum. Natural size.

Filament and spores of the same. Magn. 200 diams.

of a double papery peridium, containing
capillitium and spores, growing on rotten

wood, &c. L. epidendrum (fig. 422*) varies
from the size of a pea to that of a nut,
is globular when solitary, deformed when
growing in groups, and of a red colour. L.
parietinum is bluish black, and the peridia
do not exceed 1-20" in diameter.

BIBL. Berk. Br. Fl. ii. pt. 2. 307 j Ann.
N. H. 2 ser. v. 365; Grev. tfc. Crypt. Fl.
pi. 38 ; Fries, Syst. Mycol. iii. 79 ; Summ.
Veg. 448.

LYCOPER'DON, Mich.— A genus of
Trichogastres (Gasteromycetous Fungi) . The
species are commonly known as puff-balls,
from the cellular matter being absorbed,
leaving the spores free, mixed with a few
threads, and discharged like a puff of smoke.
The structure of the hymenium is noticed
under GASTEBOMYCETES j see also PI. 27.
fig. 6. The ignited mass of spores and
threads forms an anaesthetic.

LYCOPODIA'CE^I. —This order of
Cormophytous Flowerless Plants, which
derives its name from the Lycopodia or
Club-mosses, is difficult to characterize in
general terms. The bifurcating branched
stem, rooting at each fork by a slender
thread-like adventitious root, and the ordi-
narily small overlapping leaves, distinguish
most of the species of Lycopodium ; but
there is considerable variation from this
habit in the Psilotece, especially in Isoetes,
and the nature of the fructification is the
only mark generally applicable. The Ly-
copodiaceae bear spores which are found in
small dehiscent cases at the bases of the

Fig. 423.

Fig. 424.

Lycopodium Gayanum.

Fig/423. Scale of spike with axillary sporange ; side

view.

Fig. 424. The same seen from the outside.
Magnified 20 diameters.

leaves (figs. 423, 426, & 427), on the upper
face or imbedded in it; and these fertile

LYCOPODIACE.E.

[ 481 ] LYCOPODIACE^.

leaves are either scattered all along the
stem; or collected into spikes resembling, on

Fig. 425.

Lycop odium complanatum.
One third the natural size.

Fig. 428.

a small scale, elongated Pine-cones (figs. 425,
435). The plants of the genus Lycopodiuin
proper, exhibit both these conditions ; but

Fig. 426.

Fig. 427.

Selaginella cernua. Half natural size.

Selaginella apoda.

Fig. 426. Scale with oosporange. Magn. 20 diams.
Fig. 427. Scale with pollen-sporange. Magn. 20 diams.

in all these the spores are small and nume-
rous and alike. In Selaginella, to which
belong the elegant creeping Club-mosses,
with flattened leafy stems (often with a
metallic lustre), now so much grown in
Wardian cases (fig. 428), the capsular leaves
are in spikes, which are found forming one
arm of a bifurcation of the stem, while the
other continues the vegetative growth ; and
in the spikes we find the capsules on the
lowest scales (oosporanges) producing only
four spores (macro -
spores, figs. 426, 429),
of much larger size
than those (micro-
spores) contained in
large number in the
other spore-cases (vol-
Ien-sporange8j figs.
427, 430). In Lyco-
podium and Selaginella
the sporanges have but
one cavity; in Tme-
sipteris the sporanges
are two-celled, and in
Psilotum three-celled.
In Isoetes (fig. 376,
p. 443), where all the
leaves are seated on a
tuberous stem, and
most of them fertile,
the sporanges contain-
ing spores of each kind
are many-celled, and
immersed in the sub-
stance of the bases of
the leaves.

2i

LYCOPODIACE^:.

[ 482 ]

LYCOPODfACEJS.

Fig. 429.

Fig. 430.

Selaginella cernua. Half natural size.

Fig. 429. Oosporange with four large spores. Magn.

20 diams.
Fig. 430. Pollen-sporange burst, containing small

spores. Magn. 20 diams.

Fig. 431.

The anatomical structure of the stem of
the Lycopodiese is not very complex. There
is an outer thickish rind, composed of cel-
lular tissue; and on cutting across a stem,
the ends of isolated fibro-vascular bundles
are sometimes seen traversing this ; these
isolated bundles are merely a portion of
those forming a kind of cord running up
the centre of the stem, whence they have
been seen sent off to supply the leaves.
The fibro-vascular bundles are composed of
spiral-fibrous ducts surrounded by elongated

Fig. 432.

Fig. 433.

Lycopodium phlogmarium.

Fig. 431. Section of the stem. Magnified 20 diameters.
Fig. 432. The centre of ditto. Magnified 100 diameters.
Fig. 433. One of the isolated bundles of ditto. Magnified 200 diameters.

Fig. 434:.

Fig. 435.

r. 436.

Fig. 434. Lycopodium complanatum. Young shoot.

Fig. 435. Lycopodium lucidulum. Spike of fruit. Magnified 3 diameters.

Fig. 436 Selaginella apoda. Young shoot. Magnified 2 diams.

LYCOPODIACE^:.

[ 483 ]

LycOPODIACE.*:.

cellular tissue (see TISSUES, VEGETABLE),
which in large woody stems become ligni-
fied by secondary deposits. The roots have
also a central fibre-vascular cord, connected
with the central cord of the stem. The
structure of the little-developed tuberous
stem of Isoetes is very different, and ex-
hibits a remarkable mode of growth, form-
ing annual layers of woody structure (see
ISOETES).

The leaves are of very simple structure ;
but their arrangement exhibits many curious
peculiarities. In PSILOTUM, one of the
simplest forms, where they are mere minute
scales on a widely bifurcated stem, they
are alternate ; in some Lycopodia they are
opposite, in others whorled. When the
leaves are in whorls, they vary in number,
not only in different species, but often in the
same species in different localities, or even in
the same plant : thus, the arrangement is
often different on the main stem and on the
branches.

When the leaves are opposite, those
forming the pairs sometimes differ both in
dimensions and form ; in Lycopodium com-
planatum (fig. 434), the pairs of opposite
leaves cross alternately at right angles, so
as to form four rows up the stem ; in two
(opposite) rows the leaves are alike and
flattened laterally ; of the other two rows,
one consists of leaves like the two just
described, but flattened against the stem;
and the fourth row (opposite the third) of
minute scale-like bodies. In other cases,
as in Selarjinella apoda (fig. 436), the cor-
responding leaves of the pairs are unequal,
and are so arranged that the smaller lie
in two contiguous vertical rows, on the
front of the stem. In most of the Lycopo-
diacese the leaves are simple and almost
sessile ; but in Tmesipteris they have a blade
developed into two lobes and borne on a
long stalk ; and in Psilotum the short scale-
like leaf is also divided into two lobes and
supported on a petiole. The leaves of
Iscetes are different (see ISOETES).

The reproduction of the Lycopodiaceae is
not uniform. In Lycopodium the spores
are alike, producing monoscious prothallia ;
while in SelayineUa and Isoetes, as above
stated, two kinds of spore exist, viz. micro-
spores and macrospores. It is found that
when both kinds of spore are sown, the
results of their germination are totally
distinct. The former small dust-like spores
burst their outer coat after a time ; and the
delicate inner membrane, which is pro-

truded, likewise bursts subsequently and
discharges extremely minute eel s, in each
of which is developed an actively moving
spiral spermatozoid, like those of the FERNS.
This breaks out and swims about rapidly in
the water when seen beneath the microscope. -
The large macrospore exhibits no external
change for a period varying from a few
wreeks to a few months ; but a section
shows that a process of cell-formation has
commenced in its interior, which results in
the production of a kind of disk of cellular
tissue in the upper part, beneath that por-
tion of the outer spore-coat which exhibits
the three converging ridges produced by
the pressure of the four spores in the
parent sac during their development. At
this period the spore appears to have three
coats — an outer, tough, coloured coat, a
second coat lining this, and a third which
lines the second over the great cavity of the
spore, but at the upper part invests the
inside of the newly-formed disk of cellular
tissue, which thus lies between the second
and third coats. This disk of tissue is a
prothallium; and on its upper surface are
developed a number of vrcheyonia of very
simple structure. A cell of the substance
of the prothallium, taking on the function of
an embryo-sac, develops a free cell (embryo-
cell) in its interior ; and the cells between
this and the surface become modified and
part, so as to leave an intercellular canal
between the contiguous angles of four ad-
joining cells, leading down to the embryo-
cell, — the four cells growing up from the
surface so as to form a kind of perforated
cellular papilla, something like that of the
archegone of the Ferns. At a certain stage
of this development, the outer coat of the
spore bursts at the converging ridges, and_
the angular flaps resulting turn back and
expose the prothallium on the upper surface.
One (sometimes two, but as an irregularity)
of the embryo-cells is then fertilized by the
spiral spermatozoids produced by the micro-
spores, if these exist at the right stage of
the development in the vicinity, After
this, the embryonal cell undergoes multi-
plication, first growing down as a cellular
filament which breaks through into the
great cavity of the spore. The lower end
lying there then increases until it acquires
the form of a cellular nodule, which breaks
out above and exhibits on its free portion
the first adventitious root and the first pair
of leaves. The rootlet makes its way down-
wards into the soil ; and the leaves are

LYCOPODIE.E.

[ 484 ] LYMPHATIC SYSTEM.

gradually elevated on a thread-like stalk,
and separate, displaying two terminal buds
between them, whence the first bifurcation
of the stem proceeds.

This mode of reproduction allies the family
very closely to the double-spored Marsi-
leaceae, and separates them from the Ferns
and Equisetaceae, in which the prothallium
is ^ formed outside the spores, after the ger-
mination of the single and only kind of spore
which these plants possess. And by recent
authors, the Lycopodiacese are separated
from the Selaginaceae, on account of the
isosporous fructification of the one, and the
heterosporous fructification of the other.

The order Lycopodiacese is divided into
two families, in accordance with the struc-
ture of the sporanges :

Families.

LYCOPODIE^;. Sporanges simple, one-
celled.

:. Sporanges compound, many-
celled.

BIBL. Hofmeister, Vergl. Unters. 1851,
111; De Bary, Ann. Sc. Nat. 4 s<§r. ix. 30,
Ann. N. H. 3 ser. iii. 189; Faukhauser,
Bot. Zeit. 1873; Strasburger, Bot. Zeit.
1873 ; Sachs, Bot. 474. See also ISOETES.

LYCOPODIE'vE.— A family of Lycopo-
diaceous plants, distinguished by their
simple one-celled sporanges. The existing
kinds are all herbs, mostly creeping over the
ground ; but some of the fossil kinds, met
with especially in the Coal-measures, were
large trees, the Lepidodendra. Genera :

Lycopodium. Sporanges all of one kind,
containing numerous small spores resem-
bling pollen-grains.

Selaginella. Sporanges of two kinds, the
greater part resembling those of Lycopo-
dium ; one, situated at the base of the spikes,
larger, often four-lobed, and containing only
four large spores.

LYCOPO'DIUM, Linn.— A genus of Ly-
copodiese. This has been sufficiently cha-
racterized under the head of Lycopodiacese.
There are more than half-a-dozen British
species, mostly alpine plants ; but L. inun-
datum occurs on bogs in all parts of Britain.

BIBL. Hook, Br. Fl.; Babington, Br.
Bot. ; Francis, Br. Ferns, 8fc. See also
LYCOPODIACEJE.

LY'GEUM, Linn.— A genus of Grami-
naceae ; L. spartum is Esparto-grass.

L YGO 'DIUM, S wart z .—A genus of Schi-
zaeaceae fPolypodiaceous Ferns), consisting
of beautiful climbing plants, with conju-

gate, palmate, lobed, or pinnate leaves,
having the sessile sporanges in double rows
on the teeth of the pinnules (fig. 437), each

Fig. 437.

Lygodium reticulatum.
Portion of a leaf, with fertile pinnules. Nat size.

having a hood-like special indusium Cfio-s
438, 439).

16 sp. ; tropical. (Hook, Syn. 437.)

Fig. 438.

Fig. 439.

Lygodium reticulatum.

Fig. 438. Tooth of a pinnule with overlapping indusia.

Magn. 20 diams.
Fig. 439. The same, with the indusia removed to show

the sporanges. Magn. 20 diams.

LYMPHATIC SYSTEM.— This consists
of the lymphatic or absorbent vessels, and
the lymphatic glands.

The lymphatic capillaries commence in
the various tissues and organs, as fine net-
works or irregular lacunas. The lacunae are
connected by canals and clefts, and form a
lymph-canalicular system. The lymphatics
of the intestines — the lacteals, commence as
caeca.

In structure the lymphatics resemble the
veins, but the walls are thinner in propor-
tion to their calibre; they are also fur-
nished with valves, formed by folds of the
inner and epithelial coats.

The lymphatic capillaries are larger than
the blood-capillaries. At the surface of the
serous membranes, the lymphatics are con-

LYMPHATIC SYSTEM. [ 485 ]

LYNGBYA.

nected with small openings left between the
epithelial cells, called STOMATA ; so that the
serous cavities and the lymphatic system are
directly continuous. The lymphatics in
their onward course unite, passing through
the lymphatic glands, forming longer ves-
sels, ultimately terminating by two trunks,
one of which is the longest and called the
thoracic duct, and which terminate in the
angle formed by the internal jugular and
subclavian veins on each side.

The lymphatic or conglobate glands con-
sist of a capsule, composed of connective
tissue with scattered fine elastic fibres, and
in animals unstriated muscular fibres. The
substance of the glands consists of a cortical
and a medullary portion.

The cortical portion, which in the larger
glands forms a layer about 1-6 to 1-4" in
thickness, exhibits a coarsely granular ap-
pearance, visible externally through the
capsule. This arises from the presence of a
large number of septa or trabeculse pro-
longed from the capsule into the substance
of the organ, and dividing it into alveoli ;
these are about 1-96 to 1-36" in diameter,
and of a rounded or polygonal form ; they
are more distinct in animals than in man.
The septa consist of connective tissue with a
few fine elastic fibres, and numerous delicate
spindle-shaped bodies, often anastomosing
at their ends.

The contents of the alveoli are greyish
white, pulpy, traversed by capillary blood-
vessels, and by numerous delicate fibres,
with spindle-shaped and stellate cells re-
sembling those found in the septa, but form-
ing a lacunar or spongy adenoid tissue.
The soft substance consists of free nuclei
and rounded cells, resembling those found
in the chyle and lymph.

In the medullary portion, the retiform
tissue is very fine, closely filled with lymph-
corpuscles, and connected with a plexus of
lymphatics, ending in the efferent vessels.

The afferent vessels penetrate the capsule,
pass through the septa between the alveoli,
and open into their lacunae, which are not
lined with epithelium. From these, the
lymphatics of the medullary plexus arise,
to terminate in the efferent vessels.

The course of the lymph is from the
afferent vessels into the capsular network,
thence into the cortical and the medullary
sinuses ; from these into the network of
lymphatics of the hilus, and finally into the
efferent lymphatic vessels.

The injection of the lymphatics is a very

difficult matter. Partial injections may be
obtained by injecting the prussian-blue
liquid into an aperture made in the dif-
ferent tissues or organs. The structure of
the glands is made out, in ordinary sections
well washed to remove the lymph-corpus-
cles. See on these matters, Kutherford's
little ' Practical Histology.'

The lymph, or liquid contained in the
ordinary lymphatics agrees essentially with
the chyle, except that the molecular base is
absent; the white corpuscles forming the
characteristic microscopic elements. These
are described at p. 101.

Lymphatics in Amphibia. — The structure
and arrangement of the larger lymphatics
differ in the Amphibia. They do not form
cylindrical tubes, but lacunae, which occupy
the interspaces between the different organs,
the surface turned towards the interior of a
cavity being covered with a single layer of
tessellated epithelium. These cavities or
sacs communicate with each other by means
of microscopic openings. As there are no
contractile tissues in the walls of the sacs
special contractile organs acting rhythmi-
cally, or lymph-hearts, are superadded. A
very visible one in the frog is close to the
sacrum, and pumps the lymph into the
sciatic vein; another propels it into the
jugular. They are chiefly composed of
transversely striated short muscular laminae.

BIBL. Kolliker, Mik. Anat. ii. ; Todd &
Bowman, Phys. An. ii.; Lane, Todd's Q/c/.;
Teichmann, D. Saugad., 1862 ; Briicke, Site.
Wien. Akad. 1852-1855 ; His, Zeits. wiss.
Zool. xi., xii.,xiii. ; Recklinghausen, Strieker's
Hist, i.; E. Klein, Lymph. Syst., 1873; Sap-
pey, An. fy Phys. d. vaiss. lymph., 1875 ; Frey,
Hist. 1876, and the lit.

LYNG'BYA, Ag.— A genus of OsciUato-
riaceae (Confervoid Algae), related to Calo-
thrix and Oscillatoria, distinguished from
the former by its stratified habit, from the
latter by the long flexile but not oscillating
filaments. It contains both freshwater and
marine species. L. muralis (PI. 8. fig. 10)
grows in damp places and in water. The
specific characters are not satisfactory; but
we have found what we take to be L.
slagnina, Kiitz. Tab. Phyc. i. pi. 87. fig. 5,
and L. concinnata, Kiitz. 1. c. pi. 89. fig. 5,
in fresh water. L. speciosa, Carmichaelii,
and ferruginea, marine species, are figured
in Engl. Bot. Supp. Nos. 2926-27 a and b.

These plants appear to break up into lenti-
cular gonidia ; but their reproduction, like
that of Oscillatoria, is very obscure.

LYSIGONIUM.

[ 486 ]

MACROSPORIUM.

Braxton Hicks has stated that L. muralix,
a Sehiz'jgonium, and a Prasiola aro all dif-
ferent stages of the same organism, and has
noticed the segmentation of their gonidia
into Palmelloid cells.

BIBL. Hassall, Brit. Fr. Alg. p. 219,
pis. 59, 60, 72; Harvey, Brit. Mar. Alg.
p. 225, pi. 26 E. ; Kiitz. Spec. Alg. p. 279 ;
Tab. Phyc. i. pi. 86-90 ; Rabenh. Fl. JBur.
Alg. ii. 135 ; B. Hicks, Qu. Mic. Jn. 1861.

L YSIGO'NIUM. See MELOSIRA.

M.

MACERATION.— The soaking of ob-
jects in various menstrua, for the purpose
of causing decomposition and solution of
portions of structure which are more readily
attacked, is an operation frequently had
recourse to in the anatomy both of animals
and plants. In addition to water, cold and
hot, a number of stronger agents are often
employed, chiefly oxidizing substances, such
as NITRIC ACID, the same combined with
chlorate of potash, &c. Ammonio-oxide of
copper dissolves delicate cellulose rapidly,
and does not so soon attack woody fibre,
&c. See TISSUES.

MACHI'LIS, Latr. See PETROBIUS.

MACROBIOTUS, Schultze.— A genus
of Tardigrada (Arachnida), family Arctisca.

Char. Head not furnished with append-
ages ; mouth terminated by a sucker, with-
out palps ; skin soft, with irregular rugae.

M. Hufelandii (PI. 50. fig. 8). Body
cylindrical, colourless j head rounded in
front, with minute coloured eye-spots ;
sucker, pharyngeal tube, and styles well
developed; oesophageal bulb supported by
a solid frame- work of jointed pieces; legs
equal ; claws two, bifid, the point of each
again bifid; movement tolerably quick;
size 1-85 to 1-35".

The most common species ; found upon
mosses growing on walls, stones, at the foot
of trees, &c.

M. Oberhduseri. Dark brown; colour
distributed unsymmetrically in spots, and
forming five longitudinal bands ; no eye-
spots ; claws three, — one simple, terminal,
and forming a short filament ; the two
others hooked, the interior one double or
bifid, the posterior simple ; movement very
active ; length 1-100 to 1-85".

M. ursellus. Claws three, none fila-
mentous.

M. Dujardinii. Claws two, bifid.

BIBL. Doyere, Ann. Sc. Nat. 2 se*r. xiv.,
xvii. and xviii. ; Dujardin, ibid. x.

MACROCY'PRIS, Brady.— An Ostra-
code, allied to Bairdia, among the Cypriiltr,
with long, smooth, pointed valves, and
characterized by short setae on the upper
antennae and rudimentary postabdominul
rami. Living in the North Sea (M. minna,
Baird); fossil in the Chalk (M. siltyua,
Jones).

BIBL. G. S. Brady, Linn. Tr. xxvi. 391.

MACROGONID1A.— A name applied to
the larger form of ciliated zoospore found
in many Confervoid Algce, associated with
a form much smaller, distinguished as
MICROGONIDIA. See ZOOSPORES and HY-

DRODICTYON.

MACROSPORES, or MEGASPORES.
See SPORES.

MAC'ROSPO'RIUM, Fr.— A supposed
genus of Dematiei (Hyphomycetous Fungi J,
growing upon decaying vegetable matters,
corresponding to Septosporium, Corda, and
Helmisporium, Duby. Several species are
British. M. Cheiranthi, Fr., is common on
wallflowers and stocks j M. Brassicce, Berk.,
on cabbage-leaves ; M. sarcinula, on gourds ;
and M. concinnum, on rotting decorticated
willow twigs. We have found one species
among the OIDIUM of the vine-fungus.

Fig. 440.

Macroaporium bulbotrichum.
Magnified 200 diams.

Tulasne shows that they are conidiiferous
forms of a Sphaeriaceous genus. The spores
of different species of Macrosporium were a
very prominent feature in the organisms
observed in deposits from the air at Cal-
cutta.

BIBL. Berk. Br. FL ii. pt. 2. 339 ; Ann.
N. H. i. 261, pi. 8. fig. 10, vi. 435, pi. 12.
fig. 21; Fries, Summa Veget. 501; Si/st.
Mi/col, iii. 274 ; Corda, Ic. Fung. i. 175,
176, 188; Tulasne, Ann. Sc. Nat. 4 ser.

MACROTHRIX.

[ 487 J

MAIZE.

-v. 109 ; Cunningham, Mic. Exam, of Air,
Calcutta, 1873.

MAC'ROTHRIX, Baird.— A genus of
Entomostraca, of the order Cladocera and
family Daphniadas.

Char. Five pairs of legs ; beak directed
forwards ; superior antennae of considerable
size, one-jointed, and pendulous from the
beak ; interior antennae two-branched, pos-
terior branch four-, anterior three- jointed,
and with a very long filament arising from
the end of the first joint ; a .black spot at
the root of the superior antennae.

M. laticornis (PI. 19. fig. 25). Shell
oval, smooth, anterior margin strongly
ciliated ; eye areolar.

Found in ponds.

M. roseus. Eye without an areola ;
superior antennas longer and more slender
than in the above.

Probably a variety of the last. Found
in Scotland.

BIBL. Baird, .Br. Entom. 103; Norman
& Brady, Mon., Nat. Hist. Tr. Northumb.

MAJDOTHE'CA, Du- pj^ 441 §
mortier (Jungermannia,
L.). — A genus of Jun-
germannieae (Hepaticae),
containing two British
species: — one, M. platy-
phylla (fig. 441), com-
mon on walls, rocks, and
trees ; the other, M. Ice-
vigata, found on alpine
rocks. The sporange is
borne on a short stalk,
globose, and bursts by
four convex valves, from
which the elaters are
quite free. The globose
persistent epigone is seen
in the figure inside the Madothecaplatyphylla,
two-lipped perigone. Magn" 5 dmm8'

BIBL. Endl. Gen. Plant. Suppl i. 1341 j
Hooker, £r. FL ii. 125, JSrit. Jungermann.
pis. 35, 40, and Supp. pi. 3 ; Ekart, Synops.
Jungerm. 52, pi. 3. fig. 24, pi. 6. fig. 44.
MAGNESIA, SALTS OF.
Ammonio-phosphate of magnesia or triple
phosphate. This salt is frequently met with
in animal secretions which have undergone
decomposition, also in calculi. The most
common forms are prismatic, and figured in
the group a, b, PI. 13. fig. 1 j but their va-
rieties are endless. Those of the above
group are frequent in decomposing urine,
blood, faeces, &c. Those in group c are
occasional in urine. Those of group d are

found in the contents of the vesiculge semi-
nales. The forms e and /are rare. Fig. 2
a, b, represents the so-called penniform
crystals, or rather groups of crystals (prisms)
occasionally found in urine. Fig. 3 repre-
sents the stellate form, occasionally found
in urine; sometimes the minute and imper-
fectly formed crystals of fig. 4 are met with
in the same liquid.

The crystals belong to the rhombic system.
The prismatic crystals were formerly re-
garded as consisting of a neutral, and the
feathery of a bibasic salt ; but the composi-
tion of the two is the same, and the variation
in form depends upon the conditions under
which they are produced.

The prismatic forms may be prepared by
allowing urine to decompose spontaneously,
or by diluting this secretion with water and
gradually stirring-in very dilute solution of
ammonia in small quantities at a time j the
penniform crystals by adding excess of solu-
tion of ammonia to very dilute solutions of
the phosphate of ammonia and sulphate of
magnesia ; and the feathery forms by adding
excess of ammonia to urine. The prismatic
crystals form a beautiful polarizing object.
Sulphate of magnesia (Epsorn salt). When
crystallized upon a slide from an aqueous
solution, the prisms of this salt, mounted
in balsam, form an interesting polarizing
object ; they are also analytic.

£ or ate of magnesia fused into a bead
before the blowpipe is a beautiful obiect
(Sorby).

Urate of magnesia. See UBIC ACID.
BIBL. That of CHEMISTRY, and Phil. Mag.
1852, iii. 373.

MAG'NETITE. See ROCKS.
MAGNIFYING POWER. See MEA-
SUREMENT.

MAGOSPH^ERA, Haeckel.— A genus of
Catallacta (Protista) ; according to Kent, a
Flagellate Infusorian.

BIBL. Haeckel. Jenai. Zeit. 1870 ; Kent,
Inf. 323.

MAHOGANY.— The wood of various
species of Swietenia (Nat. Ord. Cedrelaceaa).
Cross sections' of this well-known wood
form good objects for showing the structure
of WOOD with low power.

MAIZE. — Indian corn, Zea Mays, L. —
One of the family of Grasses producing
seeds used as corn. The seeds, or rather
caryopses, are remarkably firm, being of a
horny texture in the outer part of the sub-
stance, while the central mass is more cr
less brittle nnd soft. The solidity of the

MALLOMONAS.

[ 488 ]

MARCHANTIA.

grain results from the outer cells of the
albumen being densely filled with starch-
grains (PI. 46. fig. 3), which, by pressure,
assume a parenchymatous form and cohere
together firmly. In the centre they are
loosely packed in the cells, and then are of
rounded forms (figs. 5 & 6). Figs. 1 to 4
represent successive stages of development
of the starch-grains in the protoplasmic
mass originally filling the cells, but finally
almost wholly displaced. See STARCH.

MALLO'MONAS, Perty.— A genus of
Cilio-flagellate Infusoria.

Char. Body oval, elliptic or discoid, with
brown or greenish contents ; surface covered
with long non-vibratile hairs ; a single long
anterior flagellum.

2 species j marsh-water.

BIBL. Perty, Inf. 170 ; Kent, Inf. 464.

MALPIGHIAN BODIES. See KIDNEY.

MANDIOCorMANIHOT. SeeCASSAVA.

MANILLA HEMP.— One of the most
delicate of vegetable fibres used for textile
fabrics, yielded by the liber of the fibro-
vascular bundles of Musa te.rtilis, a kind of
banana common in the Philippine Islands
(PI. 28. fig. 7). It is manufactured into
" Manilla handkerchiefs " and " Manilla
scarfs," consisting of a delicate muslin.
These are often erroneously stated to be
made of the fibre of some kind of Pine-
apple. See TEXTILE SUBSTANCES.

BIBL. Hooker's Journ. Sot. 1849, i. 28.

MARANTACE^E.— A family of Mono-
cotyledonous Flowering plants, to which
belong the true West-Indian arrow-root
plants (see ARROW-ROOT), and the Tous-
les-mois plants, species of CANNA. These
substances consist of the starch (PI. 46.
figs. 18, 25, & 26) obtained from the tube-
rous rhizomes of the plants (see STARCH).

MARATTIA, Swartz.— The typical ge-

Fig. 442.

Fig. 443.

. Marattia.

Fig. 442. Side view of a sorns.
Fig. 443. Indusium with the

sortis removed.
Magnified 12 diams.

nus of Marattiaceous Ferns. Tropical (figs.
442 & 443). Hook, Syn. 440.

MARATTIA'CE^B.— An order of Ferns,
approaching the Polypodiaceee in general

habit, but more resembling the Ophioglos-
sacese in their sporanges, which are destitute
of an annulus, and often so fused together
as to form a multilocular sac. Gen. :

Angiopteris. Caps, very close together,
opening by a lateral slit.

Marattia. Capsules concrete, opening
by internal slits.

Dancea. Caps, concrete, opening by api-
cal pores.

Kaulfussia. Caps, concrete, in raised
circular masses, openings internal.

MARBLE. See ROCKS.

MARCHAN'TIA, Micheli.— A genus of
Marchantieae (Hepaticae), Liverworts. The
most common species is M. polymorpha.
It is a little plant, not uncommon upon the
earth of damp shady courtyards, the borders
of springs, &c., extending itself in bright-
green thin lamellae of irregular lobed outline,
attached to the soil by radical hairs arising
on the lower surface. The frond presents
an upper and lower epidermis, with an
intermediate parenchyma; and the lobes
are traversed by a kind of midrib. The
upper surface is marked by raised lines
which cross each other very

leaving between them lozenge-shaped spaces
(fig. 444), in the centre of each of which

Fig. 444.

Marchantia polymorpha.

Lobe of a frond.
Magnified 10 diameters.

occurs a stoma, leading to an intercellular
space in the parenchyma. The stomata of
Marchantia are circular, and consist of six-
teen cells, arranged so as to form four rings,
one upon another, each ring being composed
of four cells ; they may be best explained
by comparing them with a chimney com-
posed of four courses of bricks, each con-
sisting of four bricks laid together to enclose
a square. The parenchyma is composed of

MARCHANTIA.

[ 489 ]

MARCHANTIA.

several layers of cells, which contain much
chlorophyll. The inferior epidermis is
clothed with radical hairs, which exhibit a
remarkable spiral marking-, arising from the

E rejection of a spirally deposited secondary
iver in the interior of the tube.
The fronds do not readily develop spo-
ranges in shady places; but when exposed to
the light, they are produced at the ends of
the ribs, at the base of the terminal notches

Fig. 445.

Marchantia polymorpha.

Plant with antheridial receptacles (male).

Nat. size.

of the lobes. The male structures are pro-
duced on different plants from the female ;
but both are borne on peculiar stalked re-
ceptacles. The first appearance of one of
these receptacles is as a little green papilla
surrounded by reddish scales, at the end of
one of the principal ribs. As it enlarges, it
pushes its way through the scales ; and the
rib on which it is borne elongates to form
a pedicel, on which it is raised up perpen-
dicularly above the surface of the frond,

Fig. 446.

Marchantia polymorpha.

Plant with fertile receptacles (female).

Nat. size.

ultimately acquiring the form of an ex-
panded cap. In the male receptacles it has
a sinuate margin (fig. 445) ; and in the female
the border is developed into eight or nine
thick cylindrical lobes (fig. 446).

The male receptacle is concave above,
with papillae consisting of the mouths of
flask- shaped cavities, in each of which is
formed an antheridium (fig. 447). These

Pig. 447.

Marehantia polymorpha.

Section through an antheridial receptacle, showing

flask-shaped cavities containing the antheridia.

Magnified 25 diameters.

antheridia are oval cellular bodies lodged in
the expansion of the cavity, with a lono*
neck projecting upward through the mouth
of the flask-shaped excavation. The cells
of the interior of the lower part of the an-
theridia produce spermatozoids (PI. 40. fig.
SSJ). The lower surface of the receptacle is
clothed with membranous processes and
hairs.

The female receptacles are somewhat

Fig. 448.

Marchantia polymorpha.

A sporangial receptacle seen from below.

Magnified 5 diameters.

MARCHANTIA.

[ 490 ]

MARCHANTIA.

convex above ; and on the under surface of
the base of each lobe are found delicate
membranous processes with toothed mar-
gins. The membranes of each two adjoin-
ing lobes form a perichcetium (fig. 448)
alternating with the lobes, concealing be-
tween them the archeyonia, which are at-
tached by their bases, and have their mouths
pointing' downwards. The archegones of

Fig. 448*.

Marchantia polymorpha.

Archegonia in various stages.

Magnified 100 diameters.

Marchantia are flask-shaped sacs with a
long slender neck (fig. 448*), containing
in their cavity a cell (germ-cell), which
after fertilization becomes developed into an
oval cellular body, the young sporangium.
In the course of the development of this, it
soon fills the cavity of the archegone, which
then begins to grow with it, and subse-
quently forms a loose sac around it — the
epiyonium — finally ruptured at the point, so
as to exhibit four or five teeth or valves,
which become recurved (fig. 449). Mean-
Fig. 449.

Marchantia polymorpha.

Vertical section of Fig. 448, showing sporanges in situ,

bursting to discharge the spores and elaters.

Magnified 10 diameters.

while another envelope grows up around
the epigone, appearing at first as a mere

ring surrounding it (fig. 448*), but
ultimately rising up so as to enclose it,
remaining open however at the summit;
this is the perigonium. In its young stages
the sporange is a mere oval mass of poly-
gonal cells ; but a distinction may soon be
detected between a cortical or peripheral
layer and the internal mass. The cells of
the former remain firmly united into a
membrane forming the wall of the sporange.
These cells grow so as to assume an elongated
form, and when mature exhibit internally a
spiral-fibrous secondary deposit (PL 40. fig.
35), analogous to that of the cells of the
anthers of Flowering plants. The cells of
the internal mass present at an early period
the appearance of a large number of fila-
ments radiating from the centre of the
sporange to the wall. These soon become
free from each other ; and it may then be
perceived that some are of very slender
diameter, and others three or four times aa
thick. The slender ones are developed at
once into the long elaters (PI. 40. tig. 36)
characteristic of this genus, containing a
double spiral fibre, the two fibres, however,
coalescing into one at the ends (fig. 37).
The thicker filaments become subdivided by
cross partitions, and break up into squarish
free cells, which are the parent cells of the
spores, four of which are produced in each
(PI. 47. figs. 10-13). The spores of M. po-
lymorpha have but a single coat ; and their
contents are bright yellow when mature.
When they germinate, the contents are
converted into chlorophyll ; and the growth
commences by the production of a tubular
process from one side of the spore.

Fig. 450.

Marchantia polymorpha.

A collection of grmmae in their involucre.

Magnified 25 diameters.

It has been mentioned that M. polymorpha
1 does not fruit freely in the shade. Under

MARCHANTIE.E.

[ 491 ]

MARSILEACE.E.

these circumstances it produces gemma,
consisting of little, compressed, oblong
masses of cells, of green colour, capable of
reproducing the plant. These are found,
when mature, in elegant cup-like struc-
tures, with toothed borders, sessile on the
upper face of the frond (figs. 446, 450).
The cup seems to be formed by a develop-
ment of the superior epidermis, which is
raised up and finally bursts and spreads
out, laying bare the gemmse, produced from
the internal parenchyma. The gemmae
consist at first of a single cell, which di-
vides so as to present an upper and a lower
(stalk-) cell ; the upper multiplies until it
becomes a cellular mass (fig. 451). The

Fig. 451.

Marehantia polymorpha.

A vertical section of the same, with nascent gemmae.
Magnified 50 diameters.

development of this structure presents much
analogy to that of the sori of the Ferns with
their iudusia and sporanges.

The Marehantia also increase by innova-
tions, or lobes of the frond becoming de-
tached from those on which they originate.

These plants form most interesting ob-
jects of microscopic investigation, in all
parts of their structure.

BIBL. Hook. Br. Fl. ii. pt. 1. 105 ; Engl
Bot. pi. 110; Mirbel, Mem. Acad. Paris,
xiii. 337, 375 ; Nageli, Linncea, xvi. 1842 ;
Henfrey, Dev. of Spores fyc., Linn. Tr. xx.
103, pi. 11 j Thuret, Antheridtes, Ann. Sc.
Nat. 3 ser. xvi. 72, pi. 12 ; Gottsche, Bot.
Zeit. 1858, Suppl. ; Strassburger, Jahr. iviss.
Bot. vii. 409 ; Sachs, Bot. 354.

MARCHANTTEyE — A family of Liver-
worts or Hepaticse. — Brit. Genera : Mar-
ehantia, Fegatella, Rebouillia, Lunularia.
See HEPATICJE.

MARGAEIC ACID and MARGARINE.
— The former general ingredient of the fatty
matters of both the animal and vegetable
kingdom, when crystallized from hot alco-
hol, forms minute needles, either isolated

or in groups (PI. 11. fig. 16 a). The crys-
tals differ from those of stearic acid, which
form lanceolate single or aggregated plates
(PL 11. fig. 16).

Margarine crystallizes from a hot alcoholic
solution in fine needles, mostly grouped or
branched, sometimes surrounding globules
of oleine, or formino; bulb-like aggregations
of needles (PL 11. tig. 15). It is sometimes
found crystallized within the cells of fatty
tissue (PL 11. fig. 15 a).

Margaric acid is now regarded as a mix-
ture of palmitic and stearic acids, and
margarine as a combination of these acida
with glycerine.

BIBL. That of CHEMISTRY.

MARGIN ULI'N A, D'Orb.— A Nodosa-
rine Foraminifer, elongate, equilateral,
curved or spiral in its earlier portion;
chambers globular or compressed ; orifice
rounded, marginal. Nodosaria raphanus
becomes Marginuline with an eccentric
aperture (PL 23. figs. 30-32); and, by gradual
modifications, Marginulina passes into Cris-
tellaria, with which Williamson unites it.

Common in existing seas ; and fossil from
the Trias upwards.

BIBL. Williamson, Rec. Foram. 30 ; Mor-
ris, Br. Foss. 37 ; Parker & Jones, Ann.
N. H. 3. xii. 432; Carpenter, Intr. For.
163.

MARSIL'EA, L.— A genus of Marsilea-
ceaB (Flowerless Plants), growing in mud,
by a creeping rhizome, from which arise
erect filiform leaf-stalks, supporting a com-
pound four-lobed blade ; at the bases of the
leaf-stalks arise also stalked capsules, cham-
bered in the interior, being divided by one
perpendicular and many horizontal septa;
in these chambers are found sacs (sporanges)
containing the spores. This plant agrees in
all essential respects with PILULABIA. See
MARSILEACE^;.

MARSILEA'CE^E.— Afamily of Flower-
less plants possessing a slight leafy stem ;
composed of a small number of plants, of
minute dimensions, but of great interest in
a physiological point of view. They are all
aquatics, some growing in the mud in and
around ponds, others floating on the surface
of stagnant waters. They all bear distinct
spore-fruits or sporocarps, seated on a stalk
arising from the stem. These contain spo-
ranges or spore-sacs, differently arranged in
the different genera, but agreeing in this
respect, that they contain spores of two
kinds, macrospores and microsporus, analo-

MARSIPELLA.

[ 492 J

MASTOGONIA.

gous to the two kinds of spore in Lycopodi-
aceae, but differing in their mode of develop-
ment.

Pilularia globulifera is the only British
representative of this family.

BIBL. Hofmeister, Vergl. Unters. 103,
pis. 21 & 22 ; Henfrey, Tr. Br. Assoc. 1851 ;
Ann. N. H. 2 ser. ix. 447 ; Hanstein, Mo-
natsb. Ak. Berlin, 1864, Ann. N. H. 1864 ;
Sachs, Bot. 444 (fig.).

MARSTPEL'L A, Norm.— A delicate are-
naceous Foraininifer, related to Astrorhiza.
(Norman, Ann. N. H. 5. i. 281 j Brady, Qu.
Mic. Jn. xix. 17.)

MARY'NA, Griiber.— A genus of Holo-
trichous Infusoria. Bodies cup-shaped,
with a funnel-shaped cleft neck ; terminal
on the ends of a branched zoary. M. socialis,
marine (Kent, Inf. 520.).

MASTIGAMQE'BA, Schulze.— A genus
of Flagellate Infusoria.

Char. Amoeba-like, changeable, creeping,
emitting pseudopodia, with an anterior fla-
gellum. Four species; freshwater. M.
aspera (PI. 53. fig. 22). (Kent, Inf. 221.)

MASTIGOB 'RYUM. See HEBPETIUM.

MASTIGOCER'CA, Ehr.— A. genus of
Rotatoria, of the family Euchlanidota.

CJiar. Eye single and cervical; tail-like
foot styliform j carapace prismatic, with a
dorsal crest.

M. carinata (PI. 43. fig. 46, side view).
Foot as long as the body ; freshwater ; entire
length 1-72".

BIBL. Ehrenberg, Infus. p. 460.

MASTIGOC'LADUS, Cohn.— A genus
of Confervoid Algae, allied to Sirosiphon.

Char. Filaments moniliform, dichoto-
mously ramose, without sheaths. Secondary
branches with cylindrical cells, among
which are some elliptical; forms a fleshy,
spongy layer.

M. lammosus (PL 52. fig. 9), in warm
springs.

BIBL. Rabenh. Fl Eur. Alg. ii. 284.

MASTIGONE'MA, Schwabe.— A genus
of Rivulariaceae.

Char. Filaments tufted, articulated, elon-
gate, with thin ends, sheathed; apex of the
sheath open. M. plana, an Irish and Scot-
tish species.

BIBL. Rabenh. Fl. Eur. Alg. ii. 226.

MASTIGOPH'ORA, Hincks,= Lepralia
pt. (Hincks, Poly*. 278).

MASTIGOTHRIX, Kiitz— A genus of
Rivulariacese.

Char. Filament single, bent, flagelliform,

ending in a produced hyaline process,
sheathed and jointed ; on freshwater
Algae.

M. ceruginosa (PI. 52. fig. 10).

BIBL. Rabenhorst, Alg. ii. 225; Kiitz.
Phijc. Genet: 232.

MASTOGLO'IA, Thwaites.— A genus of
Diatomacese.

Distinguished by the Navicula-like frus-
tules, the hoops of which are furnished with
loculi, immersed in a jnammillate frond.

Five British species, marine and fresh-
water.

M. lanceolate (PI. 51. fig. 26). Valves
lanceolate, elliptical, ends acute ; loculi
8-30 ; in brackish water.

M. Danseii = Dickieia Darnell, Thw.

BIBL. Smith, Brit. Diat. ii. 63; Thwaites.
Ann. N. H. 1848, i. 171.

MASTOGO'NIA,Ehr.— A doubtful genus
of fossil Diatomaceae.

Char. Frustules single ; valves dissimilar,
angular, mammiform, orbicular at the base,
free from umbilical processes, not cellular,
angles radiating.

The (eight) species are interesting from
the structure of the two valves of the f pus-
tules differing. Thus in one, M. Crux (PI.
18. fig. 23 a) the angles and rays are four
in one valve, but seven in the other j in

Fig. 452.

Fig. 453.

Fig. 454.

Matonia pectinata.
Fig. 452. Part of a fertile pinna. Magn. 3 diams.

Fig. 453. Indusium opened at the side, showing thecse
in situ. Magn. 25 diams.

Fig. 454. The same with the thecae removed. Magn.
25 diams.

MATONIA.

[ 493 ]

MEASUREMENT.

M. actinoptychus (PI. 18. fig. 23 6) the
angles and rays are nine in one valve, and
thirteen in the other, and so on. Diameter
from 1-1600 to 1-300".

M. hexauona (PI. 18. fig. 25).
BIBL. Ehrenb. Ber. Berl Akad. 1844;
Kiitz. Sp. Alg. 25.

MATO'NIA, JR. Brown.— A genus of
Cyathese (Polypodiaceous Ferns).

M. pectinate (figs. 452-454) Exotic.
(Hook, Syn. 45.)

MAURAN'D YA.— A genus of Scrophula-
riaceee (Dicotyledons), the testa of the seed
of which is composed of cells with spiral-
fibrous deposits, forming an elegant micro-
scopic object.

MEASUREMENT and MEASURES. — In
this article we shall consider the method
of measuring the magnifying power of a
microscope, of ascertaining the dimensions
of objects, and shall give a sketch of the
standard measures in which the dimensions
of objects are expressed.

Measurement of the magnifying power of
a microscope. — The apparent size which an
object appears to possess under a micro-
scope will vary according to the power of
the object-glass and of the eye-piece used,
and the length of the body of the micro-
scope ; and it is a good plan to determine
the measurements once for all in the case
of the various object-glasses and eye-pieces,
keeping them written upon a card, so that
they may be readily accessible.

The apparatus requisite consists of a
glass micrometer-slide graduated into thou-
sandths of an inch, each tenth division being
marked by a longer line ; or two separate
slides, one graduated into thousandths, the
other into hundredths of an inch ; and an
ivory scale, graduated into inches, tenths,
and hundredths.

The simplest method is that by double
sight, as it is called. The micrometer-slide
is placed upon the stage, the lines brought
into focus, and the image of one of the
interspaces, as seen upon the stage with the
open eye not used in looking through the
microscope, is measured with compasses.
By then dividing the measure of the image
of the space by the known measure of the
unmagnitied space, the quotient is the
required magnifying power. Thus, if the
space on the micrometer-scale is equal to
the l-100th of an inch, and the image of
the magnified space corresponds to 5-10ths
of an inch, the space is magnified 50 times :

The same result may be obtained with
the aid of the camera lucida, by placing the
microscope horizontally, and its axis at a
distance from the table equal to the distance
between the focus of the eyepiece and the.
stage ; the breadth of the image of a division
is then measured as before ; and this is the
best and most certain method.

A most important point in relation to
this subject is that the joint of the micro-
scope shall be furnished with a stop or pin
(INTRODUCTION, p. xv), by which the body
may be placed horizontally at once, so that
all objects which are drawn under . the
same object-glass and eyepiece may be
magnified to the same extent, the degree
being determined by the second of the
above methods.

The obvious use of being acquainted
with the magnifying power of a microscope
is that objects under examination may be
viewed by the same power as that with
which figures of them have been made, so
that the structure or appearance of the
objects in the two cases may be compared.
In the above estimation of the magnifying
power, one dimension only is taken 'into
account, viz. the breadth or diameter; and
this is the ordinary manner in which the
magnifying power is stated; objects are
then said to be magnified so many dia-
meters, or so many times linear.

Measurement of the size of objects. — This
is effected with the aid of a slide micrometer
passed through two slits in the eyepiece
above the stop, and at the focus of the upper
glass of the eyepiece. The breadth of the
spaces between the lines must be such as to
give an even and minute fraction of an inch.
The value of the spaces will vary with the
power of the object-glass and eyepiece ; so
that it must be determined in each case,
and recorded. For measuring small objects,
the breadth of the spaces in the eyepiece-
micrometer may be such that twenty of
them correspond to l-1000th of an inch
in the stage-micrometer slide, so that the
value of each division will be the l-20,000th
part of an inch. It is seldom that we have
to measure objects so small as this ; but the
small size is of great advantage, because in
most cases it will happen that the margins
of the objects will coincide exactly with
some of the lines, whereby the chance of
error in computation will be avoided. For
larger objects, the spaces of the eyepiece-
micrometer may be coarser.

The method of measuring scarcely requires

MEASUREMENT.

[ 494 ]

MEASUREMENT.

further explanation. Supposing, however,
that the divisions of the stage-micrometer
are equal to l-1000th of an inch, and
those of the eyepiece-micrometer equal to
1 -20,000th of an inch (t. e. twenty of them
cover one space in the former), an object
brought into focus and covering five of the
spaces of the eyepiece-micrometer, will be
l-4000th of an inch in diameter; and so
for other dimensions. When the objects
are large, the compasses and the ivory scale
will suffice for their measurement ; but
sometimes this may be conveniently done
under a low power* for the l-100ths of an
inch are not very clearly discernible to all
eyes.

In measuring objects, they must be co-
vered with thin glass, and not immersed in
too much liquid.

It is a matter of great difficulty, under
high powers, to adjust accurately the divi-
sions of the eyepiece-micrometer to those
of the stage-micrometer, or to the margins
of objects, by means of the movable stage ;
a very ingenious apparatus has been con-
trived by Jackson to overcome the diffi-
culty. It consists of a little brass frame,
in which the eyepiece-micrometer slides
from side to side, the motion being com-
municated by the end of a screw working
against one end of the slide, and resisted at
the other by a spring ; and as the magni-
fying power with which the divisions of
the eyepiece-micrometer are viewed is
small, "the adjustment is easily and accu-
rately effected.

Hartnack's diagonal scale is very useful ;
and very minute investigations and mea-
surements may be taken with it and
with Jackson's eyepiece-micrometer to
1-1 00,000th of an inch.

Other micrometers, as the "cobweb-
micrometer," are made ; but as they are
very expensive, we shall pass them over.

Some authors express the measurement of
objects by means of a ruled scale appended
to the figures or plates of them, the scale
consisting of divisions of a stage-micrometer
of known value traced off under the same
power as the objects themselves; or some-
times the divisions are ruled over the figures.
These methods are very objectionable, be-
cause the size of the objects cannot be
ascertained without measuring with com-
passes and calculation, which is almost as
bad as the size being omitted altogether.

Whenever figures of objects are given,
the magnifying power with which they are

drawn should always be expressed in num-
bers near the figures.

Measures. — The measures in which the
dimensions of objects are expressed .should
consist of parts of an English inch, and not
of a line. On the continent, fractions of a
millimetre, or of a Paris, or Prussian line are-
used. When fractions of a millimetre are
adopted, this is usually denoted by the
addition of mm to the figure or figures.

The following data will be found useful
in reducing the foreign to the English mea-
sures : —

A millimetre = 0-0393707 English inch ;
or rather less than l-25th of an English
inch.

A centimetre = 0-393707 Eng. inch j or
rather more than l-3rd Eng. inch.

A Paris line = 0-088815 Eng. inch ; or
rather more than 1-1 1th Eng. inch, to which
vulgar fraction it is nearest.

To convert a foreign into the Engli>h
measure, the former must be multiplied by
its unit- value ; thus, 0'25mm (millimetre) X
0-0393707=0-009842675 Engl. inch. But
in most cases a few decimal places only
need be observed. In this way, however,
we get a rather long sum, which may be
avoided by the use of the following Table.

Table for conversion of foreign into English
measures.

Millimetres

Old Paris lineBJ Pru,uian lines

into"
English inches.

into into
English inches. English inches.

1

•039370

•088815

•08/J817

2

•078741

•177630

•171633

3

•118132

•266445

•25745

4

•157483

•355260

•343267

5

•190853

•444075

•429083

6

•236224

•532890

•51490

7

•275595

•621705

•600717

8

•314966

•710520

•686532

9

•354337

•799335

•77235

in which the numbers in the first (or left-
hand) column correspond to the denomi-
nations expressed in the uppermost (head)
line of the three broader columns, while
the fractions opposite these numbers denote
their values in parts of the denominations
of the lowermost (head) line. Thus, 1mm—
0-039370 Eng. inch; 3^ = 0-118112; 2
Prussian lines = 0-171633 Eng. inch, and
so on. In using this Table, the decimal

MEDULLA.

[ 49.5 ] MEDULLARY RAYS.

fraction to be converted into parts of an
English inch must be broken up into its
decimal parts, and each valued separately
from the Table ; thus, to convert 0'75mm into
a fraction of an English inch —

.-, T 1 1 v
the Table)'

07mm _ 0-027oo95 )
0-05"° = Q.QQ196868 f
075mm _ 0-02952803 Eng. inch.

The only circumstance which requires
attention in the use of this Table is the
position of the decimal point. Thus, in the
above measure of 0'75mm, which, when
broken up, makes 07mri and 0'05mm, if the
first value (07) had been 7'0, the value in
Eng. inch would have been, according to
the Table, 0 275595 Eng. inch ; but this is
10 times too much, or = 7 whole milli-
metres ; hence the shifting of the decimal
point, and so on. To express the mode of
proceeding by rule, — the decimal point in
the fraction of an English inch given by
the Table should be shifted to the left, and
as many ciphers added as there are decimal
places in the foreign measure.

Harting introduced a new measure, the
T^ooth of a millimetre = -000039 in., called
a inicrornillimetre, expressed by p.. This
and its multiples are often used in foreign
works. The p is nearly equal to the -y^
of an English inch. But we agree with
Frey, that its use possesses no advantage.

Throughout this work the foot and inch
and their fractional parts are expressed for
brevity by placing respectively one or two
acute accents on their right side ; thus, one
foot is denoted by 1', one inch by 1", and
T\yth of an inch by 1-10".

MEDUL'LA OF PLANTS. — The name
formerly applied to the pith of Dicotyledons
(fig. 455 M), from a supposed analogy with

Fig. 455.

Horizontal section of a yearling shoot of a Dicotyh
don. M, medulla; EM, medullary rays; T, medullar
sheath. Magnified 25 diameters.

the medulla spinalis of animals. It affords
excellent sections of regular parenchyma-
tons tissues, as in the elder and in the tall
annual stems of many of the larger peren-
nial herbaceous plants. It sometimes be-
comes curiously chambered as it grows
older, as in the walnut and the jasmine ;
very frequently, however, it decays after a
time, leaving the centre of the stem hollow ;
this same hollow condition occurs early in
fistular stems, such as those of the Um-
belliferae, from the pith being torn up by
rapid expansion of the wood. The Mono-
cotyledons do not generally possess a defi-
nite pith ; the cellular mass, in which the
isolated FIHRO-YASCULAR BUNDLES are
imbedded, answers to a diffused pith, or
rather to the pith and medullary rays col-
lectively. It may be seen well in sections
of the flowering stem of lilies (fig. 456 M).

Fig. 456.

Horizontal section of the flowering stem of a lily.
M, medulla ; F, flbro-vascular bundles.
Magnified 5 diameters.

A more definite medulla occurs in the stem
and leaves of the rushes and sedges, where
also the cells are often elegant radiating
forms, leaving large air-canals between
them (PL 47. fig. 18). The pith of a Dico-
tyledonous stem loses itself gradually in
the terminal bud, where it is confounded
with the nascent wood and cortical layers.
In this stage its cells possess an active
vitality, which, however, is soon lost.

MEDUL'LARY RAYS.— The processes
of cellular tissue extending outwards from
the pith, between the fibro-vascular bundles
of a Dicotyledonous stem in the first year
of growth (fig. 455 RM), together with
additional interposed rays formed between
the older in each succeeding annual laver
of wood (fig. 457, 1, 2, 3, 4). The tissue of
these rays generally becomes much com-
pressed during growth ; but their size and
the degree of development differ much in

MEDULLARY SHEATH. [ 496 ]

MELANCONIEI.

different cases. In radial sections of Dico-
tyledonous wood they often appear distinctly
to the naked eye, from the direction of their
cells being different from that of the woody
fibre, and therefore reflecting light dif-

PC

Fig. 457.

Section of a four years' old shoot of the Cork oak. M, pith
1, 2, 3, 4, medullary rays of successive years ; P. C, liber layers
8, cork layers.

Magnified 20 diameters.

ferently ; this causes the "silver grain" as
it is called of oak panels, &c.; in tangential
sections of the trunk, the ends of the me-
dullary rays usually appear as short, more
or less regular, narrow streaks.

MED'ULLARY SHEATH.— The earliest
layer of fibro-vascular tissue developed in a
Dicotyledonous stem, consists ordinarily of
spiral vessels, these forming the foundation
of the wood-bundles (fig. 455 T). As the
latter stand in a circle round the pith, their
internal vascular layers of course form col-
lectively a continuous cylindrical envelope
to the pith ; this is called the medullary
sheath. It is absent in some Dicotyle-
donous stems, for example in the Oroban-
chaceae.

MEDU'S^E. See ACALEPHJE.

MEE'SIA, Hedw.— A genus of Bartra-
mioid Mosses; one species, M. uliginosa
(= Bryum trichodes), certainly British;
another, M. longiseta, doubtful.

MEESIA'CEvE.— AtribeofBartramipid
Mosses, containing two genera, of which
there are but few British representatives.
See MEESIA and PALUDELLA.

MEGALOT'ROCHA, Ehr.— A genus of
Rotatoria, of the family Megalotrochaea.

Char. Eyes two, red, sometimes disap-
pearing with age.

Rotatory organ two-lobed or horse-shoe-
shaped ; teeth in rows.

M. albo-favicans, E. (PI. 44. fig. 1).
Colourless and unattached when young,

yellowish and grouped in radiant clusters
when old; freshwater; length of individuals
1-36"; of the clusters 1-6".

The ova remain some time attached to
the parent by a cord.

M. velata, Gosse.

BIBL. Ehr. Infus. 396; Gosse,
Ann. N. H. 1851, viii. 198 ; Pritch.
In/us.

MEGALOTROCH^E'A, Ehr.— A
family of Rotatoria.

Char. Neither envelope nor cara-
pace present ; rotatory organ simple,
notched or sinuous at the margin.
Three genera :

Eyes none Cyphonautes.

Eyes present

Eye one Microcodon.

Eyes two Megalolrocha.

BIBL. Ehr. In/us, p. 394.
MEGAM'ERUS, Duges.-A genus
of Trombidina (Acarina).

Char. Palpi long, free, with a claw ;
mandibles forcipate; body constricted;
COX89 distant ; legs ambulatory — femora,
especially of the fourth pair, very large,
seventh joint short.

Several species. They live in damp
shady places, and move rapidly.

M. celer (PI. 6. fig. 33: a, labium ; b,
palp). Minute; abdomen oblong; the sides
narrowed posteriorly, covered with hairs,
and with three terminal setae; labium bifid ;
mandibles with a movable, elongated, pointed
and curved claw.

PI. 6. fig. 33 c, mandible of M. roseiis.

BIBL. Duges, Ann. Sc. Nat. 2 se*r. ii. 50;
Gervais. Walck. Arachn. iii. 169 ; Murray.
EC. Ent. 115.

MEGAP'ORA, Hincks, = Lepralia pt.
(Hincks, Pohjz. 171.)

MEGU'RA, Buckt— A genus of Aphidrc.
Black, eyes red ; on Vicia sepium. (Buck-
ton, Aphid., Ray Soc. i. 188.)

MELAMPSO'RA, Cast.— A genus of
Uredinei (Coniomycetous Fungi), distin-
guished by producing two distinct kinds of
spores — summer and winter spores. The
species are very common on the willow,
birch, poplar, &c., forming yellow or orange
spots upon the leaves. (Cooke, Handb.
522 ; Tulasne, Ann. Sc. N. 4. ii. 94.)

MELANCONI'EL— A provisional family
of Stylosporous Fungi, distinguished from
Sphseronemei by the perithecium being ob-
solete or altogether wanting. The spores,
which vary much in the different genera,
are ultimately protruded in the form of

MELANCONIOI.

[ 497 ]

MELOPHILA.

tendrils or otherwise. They are all mere
forms of Spheeriacei.

MELANCO'NIUM, Lk. — A supposed
genus of Melanconiei (Stylosporous Fungi),
so called from forming a kind of black rust
on branches of trees, reeds, &c. Several
species have been found in Britain. The
commonest is M. bicolor (JDidymosporium
elevatum, Br. Fl.), on twigs of birch. Fries
places also Cryptosporium vulgare here.
These plants are forms of Sphaeriacei. See

CONIOMYCETES.

BIBL. Berk. Brit. Flor. ii. pt. 2. p. 357 ;
Ann. N. H. vi. p. 438 ; Fries, Summa Veg.
p. 508 j Tulasne, Ann. d. Sc. Nat. 4. ser. v.
p. 109.

MEL'ANINE. — The black or brown pig-
ment met with in the choroid and uvea j in
the rete mucosum of man, especially the
negro, and animals ; in hair, feathers, &c.;
and in the blood in malaria. These pig-
ments are derived from heematine and
hseinoglobine, and exist usually in the
form of very minute granules. They are
insoluble in water, alcohol, ether, and
acids; but are sometimes soluble in alkalies
or solution of chlorine. The lungs and
bronchial glands often contain a black pig-
ment, which is unacted upon by these re-
agents, and is derived from carbonaceous
matter admitted through the respiratory
organs. (Rindfleisch, Path. Hist. 167;
Hoppe-Seyler, An. Chim. 240.)

MELANOGAS'TER, Cd.— A genus of
Hypogaeous Gasteromycetous Fungi. Two
species occur in this country, under beech,
Lombardy poplars, &c. M. variegatus (fig.
64, p. 92) is sold in the market at Bath
under the name of Red Truffle, but it has
none of the fine flavour of the real Truffle.
M. ambiguus is very fetid, smelling like
assafoetida.

BIBL. Tul. Fung. Hyp. t. 2. f. 4, 5 ; Berk.
Outl. 293 ; Cooke, Handb. 356.

MELANOTHE'CA, Fee.— A genus of
Pyrenodei (Lichenaceous Lichens).

Char. Thallus scarcely any; apothecia
verrucaroid, numerous, confluent ; hymenia
scarcely distinct ; perithecium black ; spores
8, variously divided. Two British species,
on trees. (Leighton, Lich. Flora, 498.)

MELAS'MIA, Le>. — A supposed genus
of Sphaeronemei (Coniomycetous Fungi),
but apparently only a Stylosporous form of
RHYTISMA. M. acerina occurs on the
leaves of the sycamore, forming black spots,
sometimes as much as 1-2" in diameter.

BIBL. Berk. Ann. N. H. 2 ser. v. 456 ;

LeVeille", Ann. Sc. Nat. 3 se'r. v. 276 ; Fries,
Summa Veg. 423.

MELASPI'LEA, Nyl.— A genus of Gra-
phidei (Lichenaceous Lichens).

Char. Apothecia black, superficial, artho-
noid; spores 1-septate ; paraphyses distir ct.
Five species. (Leigbton, Lich. Flora, 436.)

MELICER'TA, Schrank.— A genus of
Rotatoria, of the family Floscularisea.

Char. Bodies each in an isolated tubular
carapace or urceolus ; rotatory organ four-
lobed ; eyes two, at least when young.

M. ringens (PI. 44. fig. 3; fig. 4, animal
removed from the sheath; fig. 6, jaws).
Carapace conical or cylindrical, brownish,
composed of numerous rounded or discoidal
bodies agglutinated together ; body colour-
less. Length of carapace 1-36 to 1-24".

Frequently found attached to water-
plants, especially Potamogeton cruauf.

BIBL. Ehr. Infus. 404; Williamson,
Micr. Jn. 1852; Gosse, Tr. Mic. Soc. 1851,
iii. 62 ; Bedwell, Jn. Mic. Soc. 1878, 176 ;
Ann. N. H. 1881, viii. 448.

MELI'OLA, Fr. — A genus of Ascomyce-
tous Fungi, belonging to the division Peri-
sporiacei.

All the species are exotic, occurring on
various leaves, and distinguished bv their
jtate

sporiaia.

BIBL. Leveille, Ann. Sc. Nat. 1846, v.
266; Mont. Cuba Crypt. 327.

MELOBE'SIA, Lam.— A genus of Coral-
linaceae. Nine British species, on rocks and
other Algae (Harvey, Mar. Algce, 107). The
capsules (ceramidia) form little blunt cones,
scattered over the crusts, and containing
tufted tetraspores as in Corallina.

MELOLON'THA, Fabr. (Cock-chafer).
— A genus of Coleopterous Insects, family
Melolonthidse.

The structure of M. vulgaris, the common
cock-chafer, has been elaborately studied
and described.

BIBL. Suckow, Naturg. d. Maikafers;
Straus-Diirckheim, An. comp. d. Insect, j
Westwood, Introd.

MELOPH'ILA, Nitzsch (Melophagm,
Latr.). — A genus of Dipterous Insects,
family Hippoboscidae.

Char. Head posteriorly received in an
excavation of the thorax ; wings and halteres
absent ; last joint of the tarsus largest.

M. ovinu$, the sheep-tick (PI. 35. fig. 23).
Common upon sheep. Antennae small, sunk
in an eye-like cavity of the head ; eyes small,
oval, resembling two groups of ocelli ; setae

2K

MELOSIRA.

[ 498 ]

MEMBRANES.

three, enclosed in two sheath-like, hairy,
unjointed organs (labial palpi), resembling
otherwise those of Pulex, and arising from
the sides of a triangular labium. Legs
robust ; tarsi with two stout serrated claws,
each having at its base a blunt process ;
accompanying the claw is an elegant feathery
tarsal brush ; and on the under side of the
last tarsal joint is a bilobed pectinate organ.

BIBL. Lyonnet, Anat. et les metamor. ;
Gurlt, Magaz.f. d. gesam. Thier. 1843, ix. ;
Westwood, Introd. ; Curtis, Er. Entom. 142 ;
Pufour, Ann. Sc. Nat. 1845, iii. ; Leuckart,
Fortpflanz. der Pupiparen.

MELOSI'RA, Ag. (Gallionella,~Eh?).—
A genus of Diatomacese.

Char. Frustules cylindrical, discoidal or
subspherical, united into jointed filaments.

Hoops often very broad, to adapt them-
selves to the breadth of the new irustules.
In some species a narrow projecting ridge
or keel encircles the valves near their ends.
Valves covered with dots, which are mostly
very minute and invisible under ordinary
illumination ; in the side view they some-
times have a radiate arrangement. In some
species the margins of the ends of the frus-
tules (side view) have coarse and distinct
radiating striae.

This genus has been subdivided by
Ehrenberg and Kiitzing into : — Lysigonimn,
in which the keel is present ; and Gallionella
(proper), in which this is absent. Again, by
Thwaites into : — Aulacosira, in which the
frustules are cylindrical, surrounded trans-
versely by two furrows, with rounded (con-
vex) ends, but no line for division ; Orthosira,
in which the frustules are exactly cylindrical
(with flat ends), exhibiting the transverse
line of division, and with spherical or sub-
spherical internal cavities; and Melosira
(proper), in which the frustules are convex
at the ends, and have the central line of
division.

Numerous British species.

* Marine.

M. nummuloides, Kg. (PI. 17. fig. 5 a;
b, a frustule more magnified). Prepared
frustules colourless, distinct keel present ;
valves without markings under ordinary I
illumination; breadth 1-1500 to 1-1200".

This common species forms long, slightly
curved chains, and, on account of the great
breadth of the frustules, shows well the
various stages of subdivision. The filaments
are sometimes stipitate.

M. Borrerij Grev. Prepared frustules
dark brown, ends rounded, entire surface

punctate (ordin. ilium.), no striae nor keel j
breadth 1-850 to 1-500".

M. Dickiei (Orthosira Dickiei, Thw.)
(PI. 17. fig. 15: 0, front view; 6, side view).
Filaments short, frustules nearly colourless,
ends flat, no striae nor keel (ord. ilium.),
valves thickened so as to render the cavity
of the fruetules rounded ; breadth 1-1500 to
1-1200".

The remarkable sporangia formed in this
species (PI. 10. fig. 9) are noticed under
DIATOMACE^;, p. 249.

** freshwater.

M. (Orthosira') variant (PI. 17. fig. 6,
front view; a, side view). Frustules colour-
less, ends slightly convex and striated at the
margin (ord. ilium.), keel absent; breadth
1-1500 to 1-1200". The end view of the
frustules resembles that of Cyclotella.

Formation of sporangia shown in PI. 10.
fig. 8 a ; 6, sporangial frustule.

M. arenaria. Ends of frustules flat and
striated at the margin (ord. ilium.), the striae
appearing also in the front view ; keel
absent ; frustules broader than long ; breadth
1-660 to 1-260".

M. crenulata, Kg. (Aulacosira crenulata,
Thw. ; M. orichalcea, Ralfs) (PI. 10. fig. 7 a,
forming sporangia; 6, c, sporangial frus-
tules). Differs from the last in its less
diameter, and the frustules being two or
three times as long as broad; breadth
1-1400".

BIBL. Kiitz. Bacill 52, Sp. Alg. 27;
Ralfs, Ann. N. H. 1843, xii. 346 ; Thwaites,
ibid. 1848, i. 168 ; Smith, Br. Diat. ii. 54 ;
Rabenh. Alg. ii. 37 ; O'Meara, Q. Mic. Jn.
ix. 150.

MELOXAN'THUS, Buckt.— A genus of
Aphidae.. M. salicis. Black, legs orange,
antennae 7-jointed; on the willow. (Buckton,
Aphid., Ray Soc. ii. 21.)

MEMBRANES, UNDULATING. — These
are said to be simple membranous bands,
one margin only of which is attached, the
other being free and exhibiting an undu-
latory motion. They are allied to and
answer the same purpose as cilia. They
are described as occurring upon the sper-
matozoa of salamanders and tritons; as
forming longitudinal processes in the water-
vessels of some Anellida, as the Turbellaria ;
also as existing in some Infusoria, as Tricho-
dina, and some Rotatoria. Some authors
have regarded them as consisting of rows of
cilia or, a .spiral fibre, and not membranes.
They are most easily examined in the sper-
matozoa of the triton, in which we believe

MEMBRANIPORA.

[ 499 ]

MERfDION.

the appearance of an undulating membrane
arises from the existence of a fibre coiled
around the spermatozoa, and undulating
throughout its length (PI. 50. fig. 17).
This opinion is based upon the circumstance
that if the coiled fibre be detached from the
proper filament of a spermatozoon or sper-
matozoid, no margins of the (lacerated)
membrane can be detected other than that
visible at first, and which really represents
the coiled fibre. This, however, is an in-
teresting subject for further investigation.
Siebold, who has paid most attention to it,
remarks that Trypanosoma Grubii, a sup-
posed entozoon found in the blood of frogs
and fishes, is not an independent animal,
but simply an undulating membrane swim-
ming freely.

BIBL. Siebold, Sieb. und Kb'll. Zeitschr.
Bd. ii. 356, and the Bibl. therein.

See Mucous and SEROUS MEMBRANES.

MEMBRANIPORA, Johnst.— A genus
ofmarinePolyzoa,familyMEMBRANTPORiD^3.

Several British species; usually found in-
crusting sea- weeds, more rarely shells and
stones.

M.pilosa (PL 41. fig. 18). Orifices of the
cells with one long hair, and several spinous
teeth. Verv common.

MEMBR ANIPOREL'LA, Blainv., =Le-

aliaj pt. (Hincks, Polyz.\

MEMBRANIPOR'ID.E.— A family of
Cheilostomatous Infundibulate Polyzoa.

Distinguished by the expanded, incrust-
ing, stony polypidom, and the horizontal
quincuncial cells. Genera :

Membranipora. Cells open in front, with
raised margins.

Lepralia. Cells closed in front, poly-
pidom spreading circularly.

BIBL. Johnston, Br. Zooph. ; Busk, Cat.
Mar. Polyz. ; Gosse, Mar. Zool. ii. 16 ;
Hincks, Polyz. 127.

MENI'PEA, Lamx. — A genus of Infun-
dibulate Cheilostomatous Polyzoa, family
Cellulariadse.

Char. Cells oblong, tapering downwards,
not perforate behind, with one or two sessile
birds'-heads in front below the orifice. Two
British species.

M. ternata (Cellidaria ternata, Johnst.).
Cells elongated, greatly tapering down-
wards, 3 in each internode, with a stalked
operculum protecting the orifice ; operculum
expanded, entire, two spines on the upper
margin ; anterior birds'-head single.

BIBL. Johnston, Br. Zooph. 335; Busk,
Cat. 20 ; Hincks, Polyz. 36.

MENIS'CIUM.— A genus of Grammi-
tideae (Polypodiaceous Ferns).

10 sp. ; tropical. (Hook., Syn. 390.)

MENISCOS'TOMUM, Kt.— A genus of
Holotrichous Infusoria. Like Paramecium,
but mouth lateral, lunate ; with a vibratile
membrane. 1 sp. ; fr. wat. (Kent, Inf. 539.)

MENIS'PORA, Pers.— A genus of Mu-
cedines (Hyphomycetous Fungi), one species
of which, M. lucida, Corda, is recorded as
British, growing on decayed wood.

BIBL. Berk, and Broome, Ann. N. If.
2 ser. vii. 101 ; Corda, Ic. i. pi. 4. fig. 223.

MENOID'IUM, Perty. — A genus of
Flagellate Infusoria.

Char. Small, crescentic, thicker on the
outer margin, colourless, or greenish.

M. pellucidum, freshwater ; movement
jerking and revolving, 1-670 to 1-430".

BIBL. Perty, Lebensf. 174.

MENOPON, Nitzsch.— A subgenua of
LIOTHEUM (Anoplura); with the head
semilunar or trapezoidal, but without a deep
lateral sinuosity. The species infest poultry,
the partridge, quail, &c.

MEREN'CHYMA.— A name applied by
some authors to the form of vegetable cel-
lular tissue where the cells are of circular,
ellipsoidal, or irregularly rounded outline;
ordinarily known as lax parenchyma.

MERID'ION, Leibl.— A genus of Diato-
macese.

Char. Frustules (in front view) wedge-
shaped, united laterally so as to form seg-
ments of circles or spiral bands. Fr. wat.

Frustules in side view obovate, and fur-
nished with coarse transverse stria? visible
under ordinary illumination, which extend
into the front view.

Kiitzing distinguishes Meridian, in which
the frustules form a spiral (helical) band,
from Eumeridion, in which they form a con-
volute band.

Meridion circulare, Ag. (PI. 17. fig. 7 :

a, front view ; b, side view). Frustules in
side view simply obovate, forming a spiral
(helical) band or filament ; length of frus-
tules 1-600 to 1-375".

Meridion constrictum, Kg. (PI. 16. fig. 28,
filament flattened, and frustules (front view)
separated by drying ; a, convolute filament ;

b, side view). Frustules in side view con-
stricted near the broad end, attenuate to-
wards the narrow end, and attached to a
hemispherical stipes or cushion.

BIBL. Kiitz. Batill. 41. Sp. Alg. 10;
Ralfs, Ann. N. H. 1843, xii. 457 ; Smith,
Br. Diat. ii. 5 ; Rabenh. Alg. i. 295.

2K2

MERISMOPJSDIA.

[ 500 ]

MESODINIUM.

MERISMOP^E'DIA, Meyen.-A genus
of Confervoid Algae, consisting of minute
cells, arranged in fours and multiples, form-
ing a quadrate layer or plate. Several
species are described ; but their relation to
Gonium is obscure. Sarcina is placed in
this genus by Rabenhorst ; but Sarcina
forms a cube. See SARCINA and GONIUM.
(Rabenhorst, Fl. Alg. ii. 56.)

MERIZOMY'RIA, Ktz.— A genus of
Rivulariaceae.

C/tar. Filaments moniliform, upper cells
subulate, basal cells contained in a mucous
matrix, and constituting an amorphous
thallus. Freshwater.

BIBL. Rabenh. Fl. Alg. iii. 224.
MERMIS, Duj. — A genus of Entozoa.
M. nigrescens resembles Gordius, but dif-
fers from it principally in the vulva of the
female being transverse and situated near
the anterior end of the body, whilst in Gor-
dius this is placed at the posterior end.
Eggs black.

It is found in the newly dug-up damp
earth of gardens, and in the intestines of
insects.

BIBL. Duj. Ann. So. Nat. 2 s6r. xviii.
129, and ffelminthes, 294 ; Siebold, Ent. Zeit.
1842, 146; Meissner, Sieb. and Roll. Zeit-
schrift, 1853.

MEROT'RICHA, Mer.-A genus of Fla-
gellate Infusoria. Free, oblong, green ; fla-
gellum single, ventral; with anterior tri-
ehocysts. 1 sp., freshwater. (Kent,/w/. 249.)
MERU'LIUS, Hall. Dry-re t.— A genus of
Hymenomycetes (Basidiomycetous Fungi),
distinguished by the veiny or sinuously
plicate folds of the hymenium, these folds
not being distinct from the flesh of the
pileus, and forming angular or serrated pores.
M. lachrymans is the dry-rot fungus. The
mycelium is composed of filaments creeping
in the substance of the infected wood, dis-
organizing and feeding on this as it decays..
The mass is at first white and cottony, form-
ing an effused pileus from 1 to 8" broad ;
subsequently ferruginous or deep orange.
The irregular folds finally discharge a
watery liquid, whence the name.

The most efficacious remedies against dryr
rot are creasote and carbolic acid. Cor-
rosive sublimate, though at first efficacious,
seems to lose its virtue after a time.

Several species of the genus have been
found in England in addition to M. lachry-
mans.

BIBL. Berk. Br. Fl. ii. pt. 2, 129 ; Sow-
erby, Fungi, pi. 113.

MESOCARTUS, Hassall (Spharocarpug,
Kiitz.). — A genus of Zygnemaceae (Confer-
void Algae), with evenly distributed cell-
contents, producing in conjugation a cross
branch, in which is formed a round spore.
It often happens that all the successive
members of a long series of cells conj ugate
with another similar series, so as to produce
a ladder-like body, the " rounds " of which
are formed of the transverse processes (tra-
beculce, Kiitz.). The onlv kind of repro-
duction yet observed is tnat by the spores
formed in the transverse branch from the
conjoined contents of two cells ; but it is
possible that zoospores and encysted con-
ditions of these occur, as in SPIROGYRA and
MOUGEOTIA. The stellate encysted bodies
found in most of the allied plants have been
seen in M. scalaris by Thwaites. Thwaites
also observed a division of the contents of
the spore into four parts, such as occurs in

M. scalaris, Hass. (fig. 138, p. 204).
Sterile filaments 1-1800 to 1-1440" in dia-
meter, 6 times as long ; sporanges oval or
round. Hass. pi. 42.

M. depresses, Hass. Sterile filaments
1-2880 to 1-2400" in diarn., 6 to 8 times
as long ; spores globose or elliptical. Hass.
pi. 44. fig. 1.

M. intricatus, Hassall, is apparently the
same as M. scalaris ; all the other forms
may be brought under M. depi-cssus.

BIBL. Hassall, Alg. 166, pis. 41-45;
Kutzing, Sp. Alg. 435; Tab. Pliyc. v.
(Spheerocarpus), pis. 5-7 ; Thwaites. Ann.
N. H. xvii. 262.

MESOCE'NA, Ehr.— A doubtful genus
of Diatomaceae, according to Ehrenberg
and Kutzing.

The bodies referred to this title consist of
single siliceous rings, oval or angular frame-
works, without a centre, and mostly with
external and sometimes internal spines ari-
sing from them ; many are fossil.

Whether they are spicula of Echiiioder-
mata or not, remains to be decided. Dia-
meter from 1-750 to 1-400".

M. octogona, Ehr., PI. 25. fig. 1.

BIBL. Ehrenberg, Ber. Berl. Ak. 1840 ;
Kutzing, Bacitt. 139, Sp. Alg. 142.

MESO'CHRA, Boeck.— A genus of Co-
pepodous Entomostraca, close to Cantho-
camptus. 2 species ; brackish water. (Brady,
Copep. ii. 62.)

MESODIN'IUM, Stein. — A genus of
Peritrichous Infusoria. Free, ovate, snout-
like in front, with a ring of setose cilia

MESOGLOIA.

[ 501 ]

METOPIDIA.

2 species; freshwater and marine. (Kent,
Inf. 635.)

MESOGLO'IA, Ag.— A genus of Chor-
dariaceae (Fucoid Algee), with filiform,
much-branched, gelatinous fronds ; the axis
of the filaments composed of interlacing
longitudinal cells, with gelatinous interposed
matter ; the periphery of radiating, dicho-
tomous, coloured filaments. The fructifi-
cation consists of unilocular and multilocular
sporanges; the former are ovate sacs (fig.
458) occurring attached to the ramuli of

Fig. 4,58.

Mesogloia vermicularis.

Peripheral ramuli, unilocular sporanges and the flla-
menta upon which the jointed sporanges arise.
Magnified 50 diameters.

the periphery ; the latter are produced by
ramifications of other ramuli surrounding
them (fig. 458). Both kinds produce cili-
ated zoospores, which germinate. M. ver-
micularis (figs. 458, 459), an olive-green

Fig. 459.

Mesogloia vermicularis.

Portion of a filament.

Magnified 10 diameters.

or yellowish frond, 6" high, is common on
rocks and stones between tide-marks. M. vi-
rescens, a smaller species, is not uncommon.

BIBL. Harvey, Mar. Alg. 47, pi. 10 B ;
Phyc. Brit. pis. 31 & 83 ; Thuret, Ann. Sc.
Nat. 3 ser. xiv. 237, pi. 27.
> MESOT^'RIUM, Nag.— Probably iden-
tical with Palmoglcea. (Archer, Qu. Mic.
Jn. iv. n. s. 109.)

METACY'PRIS, B. & R.— One of the
Cytheridce : carapace tumid and cordate ;
upper antennae long and setose. Lakes and
rivers of England, Ireland, and Holland.

BIBL. Brady and Robertson, Ann. N. H.
4, vi. 19 ; ix. 51.

METACYS'TIS, Cohn.— A genus of
Holotrichous lufusoria.

Char. Free, ovate or elongate, ringed,
vesicular behind.

M. truncata, among decaying marine
algae. (Kent, Inf. 511.)

METAMORPHOSES OF TISSUES.— The
degenerations of the tissues, characterized
by an alteration in their quality and impair-
ment of function. They are "divided into
metamorphoses and infiltrations. The meta-
morphoses are characterized by the direct
change of the albuminoid constituents of a
tissue into a new material, which is usually
followed by the destruction of the histo-
logical elements, and the softening of the
intercellular substance. They include fatty,
rnucoid, and colloid degeneration.

BIBL. Green, Path, and Morb. Anat.

METEORITES.— In transparent sections
of small fragments of meteorites, many
mineral substances may be recognized here
and there ; but the microscope and even
polarized light fail to distinguish the kinds
of crystals. ^ It is best to examine the
bruised debris; and minute crystals may
be sorted out, and removed for microscopic
examination.

BIBL. Maskelyne, Proc. Roy. Soc. 1870

METOPI'DES, Quenn.— Like Metopus,
but with two or more posterior setaa. M.
contorta, freshwater. (Kent, Inf. 582 )

METOPIDIA, Ehr.— A genus of Rota-
tori a, of the family Euchlanidota.

Char. Eyes two, red, frontal; foot forked ;
carapace depressed or prismatic; anterior
and upper part of head naked or uncinate j
no hood. ^= Lepaddla with two frontal
eyes. Lorica closed beneath.

M. triptera (PL 44. fig. 7). Carapace
ovate, accurately trilateral, crested on the
back. Freshwater ; length 1-288 to 1-144".
Four other species.

METOPUS.

[ 502 ]

MICROCOLEUS.

BIBL. Ehr. Infus. 477 ; Gosse, Ann. N.
H. 1851, viii. 201.

METO'PUS, Clap, et Lach.— A genus of
Heterotrichous Infusoria, fam. Bursarina.

Char. Buccal fossa oblique and elongate,
anterior part of the body prolonged ; ante-
rior cilia stronger than those of the rest of
the surface. M. sigmoides (PI. 52. tig. 11).
BIBL. Claparede et Lach. Inf. 254.
METRID'IA, Boeck.— A genus of Co-
pepodous Entomostraca. M. armata, ma-
rine. (Brady, Copepoda, i. 79.)

METZGE'RIA, Raddi.— A genus of Pel-
lieae (Hepaticae), comprehending Junger-
tnanniafurcata, L., and J. pubescent }Sch rank,
growing on trunks of trees, rocks, &c. in
very moist places. The fronds of both are
linear-dichotomous,membranous and ribbed.
M.furcata is smooth above, hairy beneath ;
M. pubescens hairy on both sides and larger.
BIBL. Hook. Br. FL ii. pt. 1. 131 ; Br.
Jungerm. pis. 55, 56, & 73 ; Endlicher, Gen.
Plant. Supp. 1. 1338; Hofmeister, Vergl
Untersuch. 10, pi. 4.

MICA. — This mineral substance, which
is often erroneously called talc in the shops,
was formerly used for covering mounted
objects, but is now replaced by thin glass.
It is, however, occasionally useful in apply-
ing a red heat to objects, as Diatomaceae,
&c., where it is required not to change the
position of the object. It often contains
crystalline and crystalloidal inorganic mi-
neral substances, as metallic oxides, &c., of
interesting appearance.

Thin plates of mica are used also in bring-
ing out colours in objects with polarized
light. See POLARIZATION, and ROCKS.

MICRASTE'RIAS, Ag.— A genus of
Desmidiaceae (Confervoid Algae).

Char. Cell single, lenticular, deeply
divided into two-lobed segments; lobes
inciso-dentate (rarely only bidentate), and
generally radiating.

Sporangia spherical, with stout spines
(PL 14. fig. 12).

Numerous British species (Ralfs).
M. denticulata (PL 14. fig. 11, undergoing
division ; fig. 12, sporangium). Cell cir-
cular, surface smooth ; segments five-lobed ;
lobes dichotomously divided, ultimate sub-
divisions truncato-emarginate, with rounded
angles. Length 1-113". Common.

M. rotata (PL 14. fig. 13). Cell circular,
smooth ; segments five-lobed ; lobes dicho-
tomously incised, ultimate subdivisions
bidentate. Length 1-91". Common.
BIBL. Ralfs, Br. Desmid. 68; Lobb, Tr.

Mic. Soc. 1861; Dixon, Mic. Jn. 1859;
Archer, Pritchard's Infm., & Mic. Journ.
1862 ; Bailey, Smith. Contr. ; Rabenh. Alg.
iii. 187.

MICROCLA'DIA, Grev.— A genus of
Ceramiaceae (Florideous Algae), containing
one rare British species, M. glandulosa (PL
4. fig. 7), with a dichotomously branched,
filiform, compressed frond 1 to 2" high, of
a bright rose colour. Its fructification con-
sists of (1) roundish, sessile involucrated
favellae with spores, and (2) tetraspores
(tetrahedrally arranged) imbedded in the
ramules.

BIBL. Harvey, Mar. Alg. 160, pi. 22 B ;
Phyc. Br. pi. 29 ; Grev. Alg. Br. t. xix.

MICROCOC'CUS.— A genus of Schizo-
mycetes, distinguished by the minute or-
ganisms being globular instead of linear.
The species have been divided into 3 groups.
The chromogenous : as M. prodigiosus,
which is blood-red, and frequently occurs
on Fungi, cooked provisions, red milk, &c.
(see BLOOD ON BEEAD) ; M . luteus, cyaneus,
violacetis (elliptical), aurantiacus, on cooked
potatoes and hard white of egg; and M.
chlorinus on egg. The zymogenous, pro-
ducing vaiious kinds of fermentation, as
M. crepusculum = Moiias c., Ehr. ; M. urea,
in Torula-foiTn, 2-8, in urine, converting
the urea into carbonate of ammonia, and
decomposing hippuric acid. And the patho-
genous, by some considered globular Bac-
teria, producing contagious diseases : as M.
vaccinfe, in vaccine and yariolous matter;
M. diphtheriticuSj oval, in twos or more,
sometimes in colonies ; M. septicus (Micro-
sporow,Klebs), in the tissues and vessels in
pyaemia and septicaemia ; M. bombycis, in
the intestines of silkworms ; and others,
very doubtful, in the blood and sputum of
measles, in scarlet fever, typhus, glanders,
and syphilis. Collarium, Lk.. seems, at least
as regards some species, to be identical.

BIBL. Butt. Soc. Imp. d'Agric. 2 ser. vii.
727; Comptes rendus, 1852, 119; Colin,
Beit. i. 109, and ii. 148; Magnin, Bacteries;
Hallier, Phytopath.

MICROCO'DON, Ehr.— A genus of Ro-
tatoria, belonging to the family Megalotro-
chaea.

Char. Eye single; no carapace; foot styli-

form. Jaws two, each with a single tooth.

M. clavuK (PL 44. fig. 8). Body compa-

nulate, foot equalling or exceeding the body

in length. Fr. wat. Length 1-288 to 1-216".

BIBL. Ehr. Infus. p. 395.

MICROCO'LEUS, Desmaz. (Cht/iono-

MICROCYSTIS.

[ 503 ]

MICROTHECA.

blastm, Kiitz.). — A genu8 of Oscillatoriaceee
(Coiifervoid Algae), with fronds forming
strata on moist ground, paths, mud, &c.
These plants may be described as bundles
of Oscillatoria-fil&meiits enclosed in a com-
mon gelatinous sheath, which is simple or
irregularly dichotomously branched, and
forms twisted interwoven masses. The
structure of the filaments appears to be
identical with that occurring in OSCILLA-
TORIA, described under that head ; the fila-
ments oscillate : the mode of origin of the
enclosing sheath is obscure j but it would
appear to be formed of the gelatinous half-
dissolved outer membranes of the enclosed
filaments. No formation of spores or goni-
dia has been described. M. repens, Harv.
(PI. 8. fig. 9 a, the open end of a sheath),
is very common on damp paths, &c., its
sheaths are branched ; M. anguiformis,
Harv., occurs on the mud of brackish
pools; its sheaths are said to be simple.
M. gracilis, Hassall, said to be found in
similar situations, has no character attached
to it.

BIBL. Harvey, Mar. Alg. 227, pi. 26 D ;
Phyc. Br. pi. 249; Hassall,^. 260, pi. 70;
Kiitz. Tab. Phyc. i. pis. 54-58.

MICROCYS'TIS, Kiitz.— A genus of
Palmellaceae (Confervoid Algae), composed
of crowded minute spherical cells, enclosed
in a common envelope, forming solid fami-
lies. M. protog&nita (PI. 3. fig. 12), bluish
green, in long-kept water.

BIBL. Kiitz. Sp. Alg. 208; Tab. Phyc.
pis. 8, 9 ; Rabenh. Alg. ii. 61.

MICROGLE'NA, Ehr.— A genus of In-
fusoria, family Monadina, E.

Char. Tail absent ; body truncated in
front, with a single flagelliform filament ;
one or two red eye-spots present. Fresh-
water.

Probably the spores of Algae.

M. pimctifera (PI. 31. fig. 43 a). Body
yellow, ovate, subconical, attenuate poste-
riorly, two red eye-spots accompanied by
a blackish frontal spot ; length 1-620".

M. monadina (PI. 31. fig. 436). Body
ovate, equally rounded at both ends, bright
green ; eve-spot red and single ; length
1-1150 to* 1-620".

BIBL. Ehr. Infus. 25 ; Kent, Inf. 403.

MICROGONID'IA. See MACROGONIDIA.

MICROGRO'MIA, Hert.— A genus of
Reticularian Rhizopoda. The pseudopodia
of different individuals unite, so as to pro-
duce colonies. ( Hertwig, Arch. mik. An.
x. Suppl. 1.)

MICROHALO'A, Kiitz.— A genus of Pal-
mellaceae (Confervoid Algae), consisting of
microscopic gelatinous patches, floating in
water, crowded with minute green gonidia.
M. Ichthyoblabe (quite distinct from CLA-
THROCYSTIS) occurs in Britain ; and Has-
sall's Sorospora virescens belongs here. Pro-
bably a Chlorococcus.

BIBL. Kiitz. Sp. Alg. 207; Tab. Phyc.
pis. 6, 7 j Hassall, Alg. 326 ; Rabenh. Alg.
lii. 60.

MICRO'MEGA, Ag., = SCHIZONEMA pt.

MICROM'ETER. See INTRODUCTION,
p. xxviii, and MEASUREMENT.

MICROPE'RA,Lev.— A genus of Sphas-
ronemei (Stylosporous Fungi), of which
one species is described as British, M. dru-
pacearum (Cenanyium Cerasi, Junior, Fr.,
Sphceria dubia, Pers.), growing on dead
branches of the cherry-tree. It forms
whitish tubercles which split the bark trans-
versely, composed of somewhat cylindrical
conceptacles, conjoined at the base, the
white mealy ostiole projecting; the linear
spores are yellowish and curved at the
apex.

BIBL. Berk, and Broome, Ann. N. H.
2 ser. v. 380 ; Leveille, Ann. So. Nat. 3 se"r.
v. 283 ; Br. Flora, ii. pt. 2. 211.

MICROP'ORA, Gray,= Membranipora
pt. (Hincks, Polyz. 173.)

MICROPOREL'LA, Hincks, = Lepralia
pt. (Hincks, Polyz. 204.)

MI'CROPYLE (of Animals). See OVUM.

MICROSCOPE.— The first Section of
the INTRODUCTION consists of remarks upon
the microscope and microscopic apparatus.

MICRO-SPECTROSCOPE. See SPEC-
TROSCOPE.

MICROS'PORA, Thuret,= <Wm>«pt

MI'CROSPORES.— The small kind of
spores produced by Lycopodiaceae and Mar-
sileaceae in contradistinction to megaspores
or maorospores. When sown, they pro-
duce sperm-cells and spermatozoids.

MICROTHAM'NION, Nag. — A genus
of Cha&tophoracese.

Char. Filaments much branched, rigid,
jointed, narrow ; joints longer than broad,
slightly tumid. Propagation by zoogonidia.
Freshwater.

BIBL. Rabenh. Alg. iii. 365.

MICROTHE'C A, Ehr. —A marine organ-
ism of doubtful nature.

It consists of yellow, flattened, rectan-
gular (side view) bodies, with four equi-
distant spines projecting from each end ;
the colour arises from the contents; no

MICROZYMES.

[ 504 ]

MILLON'S TEST.

transverse line of division; entire length
1-216".

BIBL. Ehr. Infus. 164.

MI'CROZYMES, Bechamp.— The term
applied to the minute particles or organisms
producing fermentations, especially the
pathogenous. Most of these bodies are
considered to be forms or spores of Schizo-
mycetes, referable to the genera Bacterium,
Bacillus, and Micrococcus. Being very
minute, they are with difficulty separated
from the other constituents of the liquids
in which they occur; and the process
adopted by Chauveau and Sanderson to
isolate and prove the action of the vaccine
microzymes may be pointed out. The
vaccine matter was placed in a very small
test-tube, a little water gently addea. The
layer of leucocytes which subside first, was
separated, and on vaccination found to be
inactive. The remaining- liquid was allowed
to stand, when the soluble albuminous con-
stituents diffused into the water, but the
solution was innocuous ; the zymome-layer
was however found to be active.

BIBL. Bechamp, Comp. rend. 1868, Qu.
Mic. Jn. 1868, 274 ; Sanderson, Privy Coun-
cil Rep. 1869, 232; Hallier, Phytopathol.
1868; Roberts, Q. M. Jn. 1877, xvii. 307;
Klein, Qu. Mic. Jn. 1878, xviii. 170.

MIELICHHOFE'RIA, Hornsch.— A ge-
nus of Bryaceous Mosses, containing one
British species, M.nitida. sometimes referred
to Weissia (fig. 81, p. 121).

MILI'OLA, Lamarck. — An extensive ge-
nus of Imperforate (Porcellaneous) Fora-
minifera, in which the chambers grow alter-
nately on two or more sides of the long
axis of the suboval shell : if on two sides,
they form Biloculina(B. ringens, PI. 23. fig. 3)
and Spiroloculina (Sp.planulata, PI. 23. f . 7),
many and thin in the latter, few and thick
in the former ; if on three sides, they form
Triloculina (Tr. trigonula, PI. 23. fig. 4). Ir-
regular development of the edges of the
chambers gives rise to the many Quinque-
loculine varieties (Quinqueloculina seminu-
Inm, PL 23. fig. 6; Q. Brongniartii, fig. 6) —
from three to eight chambers being visible
on one side, and from two to six on the
other. Uniloculina ( U. indica, PI. 23. fig. 2)
is possibly a young or arrested Miliola.
Cruciloculina has a cross-slit opening, whilst
the others have usually a crescentic aper-
ture, owing to the presence of a tongue
(homologue of the septum) ; but it may be
round and produced.

In its young or Adelosine stage, Miliola

differs from Cornuspira by its segmental
stricture. See M. obesa junior, Sclmltzo,
PI. 23. fig. 1. HATJERINA and FABULAKIA
are closely allied genera.

Fossil in ah1 formations from the Trias
upwards ; and common in existing- seas,
chiefly in shallow water (M. seminulum,
PI. 23. fig. 5).

BIBL. Williamson, Rec.For. 78; Schultze,
Org. Polyth. 57; Parker, Tr. Mic. Soc.
n. s. vi. 53; Parker & Jones, Ann. N.
H. 2, xix. 299; Carpenter, Introd. For.
74.

MILK. — This liquid consists of a solu-
tion of caseine and certain salts, holding in
suspension minute globules of fatty matter
(butter).

The fluid portion possesses no microscopic
peculiarities. The globules are very nume-
rous, round, and vary in size from mere
molecules to 1-3000 or 1-2000" in diameter.
Each is surrounded by a pellicle or coat of
caseine, which prevents the globules from
fusing into each other. If a portion of a
drop of milk be placed upon a slide, and the
thin glass cover be moved to and fro, the
coat of caseine will be ruptured, the globules
of oil will become confluent, and shreds of
the coats will be visible. If acetic acid be
added, the coats will be acted upon, and the
confluence also produced. The same effect
occurs naturally in sour milk ; hence in this
the globules are often much larger than the
above dimensions, and irregular in form,
frequently becoming elongated and united
in twos, so as to bear some resemblance to
the young state of a fungus.

The milk first secreted after parturition,
called the colostrum, differs considerably
from the normal liquid. The fatty globules
contained in it vary greatly in size, often
being very large, and existing within iso-
lated or aggregated epithelial cells, some of
them resembling exudation-corpuscles.

Peddie's paper on the human milk in
relation to medical practice, is well worthy
of perusal.

BIBL. Kolliker, Mik. An. ii. ; Donne,
Cours de Micros. ; Wagner, Hand. d. Phy-
siol. art. Milch ; Peddie, Ed. Mn. Jn. 1840,
and CHEMISTRY.

MILK- VESSELS. See LATICIFEROTJS

TISSUE.

MILLON'S TEST, or TEST-LIQUID.—
This is a strongly acid (nitric and nitrous)
solution of proto- and pernitrate of mercury,
made by dissolving metallic mercury in its
weight of strong nitric acid, with the aid of

MILNESIUM.

[ 505 ]

MNIOIDE.E.

heat. It gives a red colour to certain sub-
stances, gently boiled in it.

The following substances and tissues are
coloured red by the test : albumen, caseine,
chondrine, crystalline, epidermis, feathers,
fibrine, gelatine, gluten, horn, legumine,
proteine, silk, wool.

The following, when pure, are not co-
loured : cellulose, chitine, cotton, gum (ara-
bic), linen and starch.

BIBL. Millon, Compt. Rend. 1849, or
Chem. Gaz. 1849, vii. 87.

MILNE'SIUM, Doyere. — A genus of
Arachnida, of the order Tardigrada (Colo-

". Head with two very short palpi-
form appendages at its anterior and lateral
parts ; mouth terminated by a sucker sur-
rounded by palps ; skin soft, transversely
furrowed ; legs four pairs ; rings of the body
divided into two segments.

M. tardigradum (PI. 50. fig. 9). Mouth
surrounded by six minute unequal palpi,
symmetrically arranged, diminishing in size
from the upper to the lower part; head
rounded in front when the mouth is re-
tracted ; eye-spots tolerably large and gra-
nular; pharyngeal tube much dilated, styles
very small, bulb elongated and pvriform,
without an internal framework ; body trans-
parent, attenuated at both ends, especially
the posterior ; skin pale brownish yellow ;
three anterior pairs of legs nearly equal, the
fourth very short, resembling two tubercles,
with scarcely a trace of annuliform division ;
claws four, two terminal, and in the form of
elongated filaments hooked at the end, and
each supported on a distinct tubercle ; two
inferior and internal, the anterior divided
into three strongly curved hooks, the pos-
terior into two ; hooks or terminal filaments
of the fourth pair longer than those of the
first three. Movement active. Length
1-50 to 1-40".

BIBL. Doyere, Ann. Sc. Nat.

MIMOSEL'LA, Hincks.— A genus of
Ctenostomatous Polyzoa, fam. Vesiculariidae.

Char. Zoary confervoid, jointed, and
branched ; cell's ovate, opposite, with a basal
joint; animals with eight tentacles and a
gizzard.

M. gracilis. Branches erect, arising from
a creeping fibre. On sea-weeds.

BIBL. Hincks, Polyz. 555.

MINERALOGY, APPLICATION OF THE
MICROSCOPE TO. — The following substances
may be recognized in transparent minerals
or blowpipe beads, by means of the cha-

racteristic absorption-bands seen in the
spectrum, even when they are much co-
loured by the oxides of iron, manganese, or
nickel, viz. didymium, erbium, uranium,
cobalt, chromium, copper, manganese, and
jargonia. In one method the substance is
fused with borax or microcosmic salt, so as
to give a clear bead, and the spectrum is
examined by means of the spectrum eye-
piece. In the other method, the saturated
borax bead is kept hot over the lamp, so
that crystals may be deposited in it. Many
kinds of crystals may be thus distinguished.
See SPECTROSCOPE and ROCKS.

BIBL. Sorby, Qu. Mic. Jn. 1869, 182.

MIRROR OF SCEMMERING. See
INTRODUCTION, p. xxii.

MISCHOCOC'CUS, Nag. A genus of
Palmellacese.

Char. Thallus gelatinous, branched ; the
terminal cells of the branchlets in pairs or
fours. In boggy pools.

M. confervicola (PI. 52. fig. 12).

BIBL. 'Rabenht. Fl. Alg. Eur. iii. p. 54.

MISTLETOE. See VISCUM.

MITES. — The animals usually included
under this term are species of Acarina.

MITOPH 'ORA, Perty — A genus of Cilio-
Flagellate Infusoria. Free, ovate, with"fc
lateral row of parallel stout cilia, and a long
terminal flageHum. M. dubia, freshwater.
(Perty, Lebens. 153.)

MNIA'CE^E.— A tribe of Mnioide»
(Mosses), of Bryoid habit, but with firm,
rigid, and usually undulated leaves, mostly
increasing in size toward the top of the
stem. British genera: Cinclidium, Geor-
gia, Mnium, and Timmia.

MNIADELPHA'CE^E.— A family of
Pleurocarpous Mosses, with the leaves ar-
ranged in four or more series, and composed
of parenchymatous cells, mostly equally
hexagonal and Mnioid, very smooth, pellu-
cid, destitute of a distinct primordial utricle,
the lowest decurrent on the stem at the base,
larger, spongy, lax, mostly beautifully dark-
tinged, never single, slender. Brit, genus :

DaUonia. Calyptra mitre-shaped, bell-
shaped, elegantly fringed at the base. Pe-
ristome double (Neckeroid) : outer, sixteen
narrow, subulate, trabeculate teeth, reflexed
when moistened ; inner, an equal number
of similar cilia, alternating with the teeth,
devoid of a basilar membrane.

MNIOI'DE^E.— A family of operculate
Mosses, ordinarily of acrocarpous habit, but
sometimes pleurocarpous, with broadly oval,
spathulate, ov4 or lanceolate, flattish leaves,

MNIUM.

[ 506 ] MOLECULAR MOTION.

having a very prominent, thick dorsal nerve.
The base of the leaves composed of some-
what parallelogrammic cells, rounded-hexa-
gonal or with equal walls towards the apex,
very full of chlorophyll, or with the pri-
mordial utricle mostly very conspicuous, or
much thickened, firm, rarely papillose. This
family is divided into two tribes: MNIA-
CE^E and POLYTRICHACE.&:.

MNI'UM, Dill. — A genus of Mniaceous
Mosses, of acrocarpous and pleurocarpous
habit, including many Brya of the British
Flora. Among the commonest is M. hor-
num=£ryum hornum, L.

MOCHA STONES. — The varieties of
chalcedony known under this name contain
a number of bodies (mineral dendrites)
which have been mistaken for plants.

Compare AGATE, SILICA, and FLINT.

BIBL. K. Miiller, Ann. N. H. 1843, xi.
415.

MOH'RIA, Swartz.— A genus of Schizae-
aceous Ferns.

M. thurifraga (fig. 4GO) ; Cape. (Hook.
Syn. 436.)

Fig. 460.

Mohria thurifraga.

A pinnule with sporanges.

Magnified 25 diameters.

MOI'NA, Baird. — A genus of Entomos-
traca, order Cladocera, and family Daphni-
ada.

Char. Head rounded and obtuse ; supe-
rior antennae of considerable length, of one
piece, and arising from the front of the head
near the middle; inferior antennae large,
fleshy at the base, and two-branched, one
branch three-jointed, the other four- jointed ;
legs five pairs. Freshwater.

M. rectirostris (PI. 19. fig. 23). Cara-
pace almost straight or but slightly rounded
behind.

M. brachiata or Iranchiata. Carapace
greatly rounded behind.

BIBL. Baird, Br. Entomos. 100; Grobben,
Entw., Jn. Mic. Soc. iii. 77.

MOIST CHAMBER. — Introduced by

Recklinghausen, improved by Schultze and
others ; it enables the object under micro-
scopic examination to be placed in a space
saturated with moisture, and to be examined
without or with the intervention of thin
glass. Also it enables an immersion-lens to
remain with its water in contact with thin
glass over an object in any liquid for a con-
siderable time. The simplest form is that
of a large glass ring cemented to a broad
glass plate : a thin and flexible caoutchouc
membrane is fixed to the ring and to the
object-glass by india-rubber rings. The
growing-slide mostly answers the same pur-
pose. See Frey, Mik. 63; Rutherford,
Hist. 150 ; Dallinger and Drysdale, M. M.
Jn. xi. 97.

MOLECULAR MOTION.— When ex-
tremely minute particles of any substance
immersed in water or other liquid are exa-
mined under the microscope, they are seen
to be in a state of vivid motion. A little
gamboge or Indian-ink mixed with water
will exhibit the phenomenon distinctly
enough. The minute particles or molecules
are seen to move irregularly, to the right
and left, backwards and forwards, as if re-
pelled by each other, until the attraction of
gravitation ultimately overcomes the force
upon which their motion depends, when
they sink to the surface of the slide. This
applies to the molecules of those substances
which are heavier than water. In the case
of those which are lighter than water, or
the liquid in which they are immersed, the
molecules ultimately become adherent to
the thin glass covering the slide.

This motion is in no way connected with
evaporation, for it takes place equally when
this is completely prevented, just as when
it is not. Neither light, electricity, mag-
netism nor chemical reagents exert any
effect upon it. Heat is the only agent
which affects it ; this causes the motion to
become more rapid. Hence it might be
attributed to the various impulses which
each particle receives from the radiant heat
emitted by those adjacent. Or, as it takes
place when the temperature is uniform, may
it not arise from the physical repulsion of
the molecules, uninterfered with by gravi-
tation, hence free to move ? The effect of
heat would then be explicable, because this
increases the natural repulsion of the parti-
cles of matter, as in the conversion of water
into vapour.
Molecular motion plays a part in some

MOLGULA.

[ 507 ]

MONADIXA.

common phenomena. Thus, it prevents
turbid water from becoming rapidly clear by
repose ; by its agency also the disaggregated
particles of animal or vegetable matter are
diffused throughout the mass of the liquid.

The microscopist should become ac-
quainted with the appearance of particles in
molecular motion, as it might give rise to
error; and it often occurs in animal and
vegetable cells. Thus particles under its
influence might be mistaken for monads ; or
particles moved by cilia might be regarded
as merely exhibiting this molecular motion.

Two circumstances appear most favour-
able for its production and continuance, in
addition to the augmentation of tempera-
ture, viz. a very finely divided state of the
matter, and the specific gravity of the matter
and the liquid in which it is suspended being
as nearly as possible coincident.

BIBL. Brown, On, Active Molecules (pri-
vately printed); Duj. Observ. au Mic.;
Griffith, Med. Gaz. 1843 ; Delsaulx, M. Mic.
Jn. xviii. 1 ; Hartley, ib. 8 ; Jevons, Qu. Jn.
Sc. 1878, 167 j Ord, Jn. Mic. Soc. 1879,
656.

MOL'GULA, Forbes. — A genus of Tuni-
cate Mollusca, of the family ASCIDIAD^E.

Two British species : M. oculata, adherent,
bluish or purple, mottled with orange, 2^" in
diameter ; and M. tubulosa, free, in sand.

BIBL. That of the family.

MOL'GUS, Duj ., = Bdella pt. 2 species ;
on marine sands. (Dujardin, Vlnstitut, 1842,
316 ; Gervais, Apt. 158.)

MOLLUSCA.— Every portion of the
structures of the Mollusca offers objects of
interest to the microscopist. The motion
of the cilia, the structure of the lining
membrane of the viscera, the spermatozoa,
the ovular growth and the nature of the
sensory organs can be easily investigated.
Remarks upon certain interesting structures
occurring in the Mollusca will be found
under TONGUE, SHELL, SNAILS (WATER-),
MUSSEL, OYSTER, and OVUM. The calca-
reous concretions, crystals, and spicula met

with in the integument or mantle of some
mollusca are curious.

BIBL. Siebold, Vergl. An. and the co-
pious BIBL.; Vogt, Zool. Brief e; Adams,
Recent Mollusca] Forbes and Hanley, Br.
Mollusca ; Woodward, Shells ; Jones, An.
Kingdom, and Cycl. of An. and Phys. ;
Huxley, Comp. Anat., and EngL Cyclop. ;
Deshayes, Hist. Nat. Moll. ; Turton, Br.
Shells, by Gray ; Jeffreys, Br. Conch, (figs,
of all species, mar. and frw.) ; Rimuier, Br.
Id. and freshwater Shells.

MONACTI'NUS, Bail.— A genus of Des-
midiaceae = MONACTINIUM, Braun.

Distinguished from Pediastrum by the
marginal cells having one horn only.
Species : — M. octonarius : marginal cells
eight, central none. M. duodenarius (PL 36.
fig. 28) : marginal cells twelve, central
three.

BIBL. Bailey, Smith. Contr. 1853, 14;
Rabenh. Ala. lii. 71.

MONADI'NA.— A family of Infusoria,
according to Ehrenberg's system, but con-
sisting of a heterogeneous group of imper-
fectly examined bodies.

Char. Carapace absent ; no expansions ;
locomotive organs consisting of one or more
flagelliform filaments or cilia at the anterior
part of the body.

Ehrenberg distinguishes nine genera :

A. Tail none.

a. K"o lips.

a. Swimming.

a. No eye-spot.

Single 1. Monas.

Grouped 2. Uvella.

ft. Eye-spot present.
Single.
* Flagelliform filaments

one or two 3. Microglena.

** Flagelliform filaments

four or five 4. Chloraster.

*** Flagelliform filaments

numerous 5. Phacelomonat.

Grouped 6. Glenomorum.

b. Soiling 7. Doxococnts.

b. Lips present 8. Chilomonas.

B. Tail present 9. Bodo.

Dujardin divides them thus :

MONADLN-A.

moving throughout its whole length 1. Monas.

.

ior prolongation .................. 3. Chilomonaa.

Two equal filaments terminating the curved angles of the anterior end ........................... 6. Trepomonas.

Four equal filaments in front, and two thicker ones behind ............................................. 7. Hexamita.

A second filament arising from the same spot as the flagelliform filament, but thicker,

trailing and retracting ............................................................................................. 8. Heteromita.

A filament and vibratile cilia ............. .......................................................................... 9. Trichomonas.

................................................................................... 10. Uvella.

ups originally fixed at the end of a branched polypidom or stalk .............................. 11. Anthophysa.

9 _a f Groups always free, revolving
=£ Exl G'rouPs originally fixed at the

MONADS.

[ 508 ] MONOCOTYLEDONS.

Dujardin's characters are : — animalcules
without an integument, consisting of a glu-
tinous, apparently homogeneous substance,
susceptible of becoming agglutinated to
other bodies, and so drawn out and altered
in form, with one or more flageUiform fila-
ments as locomotive organs, and sometimes
lateral or tail-like appendages.

BIBL. Ehr. Infus. 1; Duj. In/us. 270;
Dallinger, M. M~Jn. xiii. 185 ; Cienkowski,
chultze's Arch. xii. 227.

MONADS are species of Monas, or other
Monadina.

MONAS, Mull. — A genus of Infusoria, of
the family Monadina.

M. Dauingerii. Ovate, pointed, no nucleus
nor contractile vesicle ; length 1-4000". In
fish- (cod) macerations. Propagation by
transverse fission ; and by spores after con-
jugation and encystment. The germs of
these monads survive a temperature which
destroys the adults.

M. vinosa, E. Ovate, uniformly rounded
at each end, of a red-wine colour, motion
slow and tremulous. Length 1-12,000 to
1-6000".

Found upon the sides of glass vessels in
which decaying vegetable matter has been
kept, on the side next the light.

M. lens, D. (PI. 31. tig. 44 a). Body
rounded or discoidal and tubercular. Breadth
1-5200 to 1-1800".

One of the most common organisms in
animal and vegetable infusions. We have
found one common in animal infusions
(PI. 31. fig. 44 6), perhaps the same as the
above ; but it possesses usually two fila-
ments : on the left side is one without fila-
ments, but with the body drawn out from
adhesion to the slide.

M. attenuata, D. (PI. 31. fig. 44 c). Body
ovoid, narrowed at the ends, nodular, un-
equal ; filament arising from the anterior
narrowed portion. Length 1-1600". Very
abundant in fetid films floating on water
containing decaying freshwater Algae.

M. prodigiosa, see MICROCOCCUS.

Several other species ; many probably
consisting of the zoospores of Algse, or the
swarm-germs of other Infusoria.

BIBL. Ehr. Infus. 3-, Duj. Infus. 279;
Kent, Inf. 232.

MONE'RA, Haeckel.— A group of Pro-
tista, forming the simplest of all organisms,
the protoplasm or sarcode constituting the
whole structureless body; nuclei and cell-
membranes are never developed. The Mo-
nera are subdivided into Gymnomonera and

Lepomonera. The Gymnomonera do not
pass into a quiescent or resting condition,
and do not surround themselves with a
covering, and propagate by fissiparous divi-
sion. The Lepomonera pass into a resting
stage, and surround themselves with a co-
vering for the purposes of reproduction —
breaking up into spore-like bodies, which,
on escaping, resemble the parent form.

BIBL. Cienkowski, Schnitzel Arch. 1865,
i. 203 ; Haeckel, Zeit. wiss. Zool 1865, xv.
360 ; Gener. Morph. Jenai. Zeit. 1868, iv. ;
Wright, Qu. Mic. Jn. 1869.

MONOCER'CA, Bory.— A genus of Ro-
tatoria, of the family Hydatinaea.

Char. Eye red, single, cervical; foot-like
tail simply styliform.

Gosse mentions a second eye situated in
the breast of one species. Ehrenberg de-
scribes three species, to which Gosse adds
two.

M. rattus, E. (PI. 44. fig. 9). Body ovate-
oblong; forehead truncate, unarmed; foot
styliform, as long as the body. Aquatic.
Length 1-120".

BIBL. Ehr. Infus. 422; Gosse, Ann. N. H.
1851, 199.

MONOCOTYLEDONS. — One of the
classes of Angiospermous Flowering Plants,

Fig. 461.

Reduced view of a stem of a Palm, showing the per-
pendicular and horizontal section, in which the fibro-
vascular bundles F.V are seen isolated in the medullary
parenchyma.

so called from the structure of the embryo
contained in the seed, which in a large num-
ber of cases is of microscopic dimensions,
and always requires the use of the simple
microscope for its dissection. Some of the
families placed under this head have usually
an acotyledonous embryo, as Orchidaceae ;

MONOGRAMMA.

[ 509 ]

MONSTRILLA.

but these possess the character of the class
in all other respects. Among the most im-
portant of their other characters is the iso-
lated condition of the fibre-vascular bundles
forming the woody structures (see TISSUES,
VEGETABLE). This character, mostly very
evident both in perpendicular and horizon-
tal sections of the stems, is illustrated by
figs. 456 & 461.

MONOGRAM'MA, Schk.— A genus of
Grammitideae, consisting of small grass- or
rush-like plants, the simplest in structure
of all the Ferns. Several species, tropical.
(Hooker, Synops. 374.)

MONOL'ABIS, Ehr.— A genus of Rota-
toria, of the family Philodintea.

Char. Eyes two, frontal; tail-like foot
with two toes ; horns absent.

Two species.

M. gracilis (PL 44. fig. 10). Body slender,
no cervical process nor respiratory tube;
teeth two in each jaw ; freshwater. Length
1-240 to 1-144".

BIBL. Ehr. Infus. 497.

MONOR'MIA, Berkeley.— A genus of
Nostochaceae (Confervoid Algae), with a
definite, linear, convoluted frond, enclosing
a single moniliform filament ; differing from
Nostoc in the convoluted frond being devoid
of the common membranous pellicle. Mo-
normia intricata occurs in gelatinous
masses, about as large as a walnut, of a
reddish-brown colour, floating in slightly
brackish ditches. When the spermatic cells
are quite mature, the definite outline of the
linear frond is almost lost, and there is little
to distinguish the plant from Trichormus,
except the peculiar convolutions of the
moniliform filament; the frond then also
assumes a greenish tint.

BIBL. Berk., Glean, of Br. Alga, t. 18 ;
Ralfs, Ann. N. If. ser. 2. vol. v. pL 8. fig. 1 j
Harvey, Phyc. Br. t. 256 ; Hassall, Algae, t.
75. fig. 11. Nostoc intricatum, Meneghini,
Anabcena intricata, Kiitz., Tab. Phyc. i. t. 94.
fig. 1 ; Rabenhorst, Alg. ii. 183.

MONOSI'GA, Kt.— A genus of Choano-
$agellate Infusoria.

Char. Bodies naked, solitary, sessile or
stalked, with a single tiagellum, and an an-
terior funnel-shaped collar composed of sar-
code. Nine species, freshwater and marine ;
1. 1-5000 to 1-2500". (Kent, Infus. 329.)

MOXOSPI'LUS, Sars. — A genus of
Lynceidse (Entomostraca).

Char. Carapace of series of superimposed
valves; head depressed; no compound
eye.

BIBL. Norman and Brady, Mon. Nat.
Hist. Tr. Northumb.

MONOSTE'GIA, D'Orb. ; MONOTHA-
LA'MIA, Schultze. — Instituted as an order;
but one-chambered Foraminifera are found
in most of the chief families, and therefore
cannot constitute a separate group. Thus
Proteonina, Squamulina, Cornuspira (PL 23.
fig. 13), Vniloculina (PL 23. fig. 3), Tro-
chammina (PI. 23. fig. 14), Saccammina,
Astrorhiza,Lagena(¥\. 23. figs. 22-27), Ovu-
lites, Orbulina (PL 24. fig. 1), and Spirittitia
(PL 24. fig. 5) are either usually or constantly
unilocular.

MONOSTRO'MA, Thuret.— A genus of
Ulvaceae (Confervoid Algae), of which M.
bullosum (Ulva bullosa, Roth) is the type,
distinguished from Ulva by consisting only
of a single layer of cells, and these being
roundish (mostly grouped in fours), im-
bedded in an apparently homogeneous ge-
latinous membrane (PL 9. fig. 1 a). This
plant is reproduced by zoospores formed
from the cell-contents, and discharged by
bursting of the cell-wall (fig. 1 6, c). They
have four cilia.

Currey has described, under the name of
M. roseum, a plant which we think scarcely
referable here, but rather to MICROCYSTIS.

BIBL. Thuret, Ann. Sc. Nat. 3 sfo. xiv.
225, pi. 21. figs. 1-4 ; id. Mem. Soc. Sclent,
de Cherbourg, ii. 1, 1854.

MONOSTY'LA, Ehr.— A genus of Rota-
toria, of the family Euchlanidota.

Char. Eye single, cervical ; tail-like foot
simply styhform ; carapace depressed.

Four species : three, Ehrenberg ; and one
other, Gosse.

M. quadridentata (PL 44. fig. 11). Cara-
pace yellowish, fore part of head deeply
cleft in four horns; freshwater. Length
1-120".

BIBL. Ehr. Infus. 459; Gosse, Ann. N. H.
1851, viii. 200.

MONOTOS'PORA, Corda.-A genus of
Dernatiei (Hyphomycetous Fungi), of which
one species has been found in England,
growing on dead bark of the yew. M. me-
galospora, Berk, and Br. Filaments erect,
simple, straight, nearly equal, articulated.
Spores terminal, obovate, even, -00133 to
•0014" long. Fries regards this genus with
doubt.

BIBL. Berk, and Broome, Ann. N. H.
2 ser. xiii. 462, pi. 15. fig. 11 j Fries, Sum.
Veg. 497.

iMONSTRIL'LA, Dana. — A genus of
Copepodous Entomostraca. M. Anglica',

MONTAGNITES.

C 510 ]

MOSSES.

Weymouth. (Lubbock, Ann. N. II. 1857,
xx. 401 ; Brady, Cop. iii. 37.)

MONTAGNITES, Fr. — A genus of
Agaricini (Hymenomycetous Fungi), distin-
guished by the dry gills which project after
the universal volva breaks off from the
edge of the pileus.

One species occurs in the south of France
and Algeria, another in Texas, and a third
in Siberia, in dry sandy soil; extremely
interesting as connecting the Hymenomy-
cetes with the Gasteromycetes.

BIBL. Fr. Ep. 241 ; FL Alg. t. 21. f. 2.

MONU'RA, Ehr.— A genus of Rotatoria,
of the family Euchlanidota.

Char. Eyes two, frontal ; foot simply sty-
liform. Carapace somewhat compressed
and open beneath.

Two species.

M. dulcis (PI. 44." fig. 12). Carapace
ovate, obliquely truncate and acute behind ;
eyes distant. Length of carapace 1-280".

BIBL. Ehr. Infus. 474.

MOOR'EA, J. & Kirkby.— A fossil Os-
tracode, known by its suboval depressed
valves, with raised margins. Found in
Silurian and Carboniferous rocks.

BIBL. Jones & Holl, Ann. 2V. H. 4. iii.
225.

MORCHEL'LA, Dill— A genus of Asco-
mycetous Fungi, distinguished by its stipi-
tate receptacle, which is deeply folded and
pitted.

Four species occur in this country, amongst
which M . crassipes is the giant of the genus.
The species are esculent, and largely im-
ported. They are very abundant in some
parts of India, especially in Kashmir. They
often occur on cinder walks and burnt soil.

BIBL. Grev. Crypt. FL tab. 68, 89 ; Berk.
Outl. t. 21. f. 5 ; Cooke, Handb. 655.

MORPHIA. See ALKALOIDS, p. 31.

MORPHO, Fabr.— A genus of Exotic
Lepidopterous Insects.

M. Menelaus. The scales from the wings
of this beautiful insect are sometimes used
as TEST-OBJECTS.

MORTIEREL'LA.— A genus of Muce-
dines, with branched threads like a cande-
labrum, on the underside of which spo-
rangia are produced ; zygospores have also
been found. Moulds of great elegance.
Martensella, an allied genus, has pectinate
sporangia. (Coemans, Bull. Ac. Belgiq. xv.
544 ; Bary & Woronin, Beit. 4 ; Brefeld, iv.

LOSSES, MUSCACE^E.— This order of
floweiiess plants is distinguished from the

Hepaticse by the vegetative structure and
by the sporanges. In one group alone
(Hypopteryyiece) is the stem clothed with
leaves, accompanied by amphigastria (sti-
pule-like leaflets), in the manner of the
loliaceous Hepaticse (fig. 355, p. 409) : and
here the sporange is a stalked urn-shaped
body, with a deciduous lid, and like those
of the Mosses generally ; and this Jun-
germannia-like leafy stem is erect, and not
procumbent as in Jungermannia itself. In
all other Mosses the leaves clothing the
stem are arranged in a spiral order around
the stem, so as to give the vegetative struc-
ture a very characteristic aspect. On the
other hand, the Andraeaceae, which have
a valvate capsule, have spirally-arranged
leaves.

The stem of the Mosses is a slender
thread-like wiry structure, wholly com-
posed of cellular tissue, without vessels ; but
the external layer has an epidermoid cha-
racter, while the central portion is com-
posed of elongated cells. In one section of
the Mosses this stem terminates in a spo-
range, and these are called Acrocarpous
Mosses; in others the sporanges spring from
lateral branches, and the ter-
minal bud of the stem elon- Fig. 462.
gates the stem year after year ;
these latter are called Pleuro-
carpous Mosses. In some of the
genera the sporanges are borne
terminally on short special
branches, as in Sphagnum,
Mielichhoferia, part of Fissi-
dens, Guembelia fontinaloides
(tig. 289, p. 366) ; these are
termed Cladocarpous.

The leaves are of simple
structure, usually composed
of a single layer of cells, the
forms of which are used as
characters by systematic Mus-
cologists. They are either all
alike in a leaf, and filled with Ephemerum
chlorophyll, and in these cases
may be either parmchymatous
(PI. 47. fig. 19) or prosenchy?
matous (PI. 47. fig. 20). In other cases two
sorts of cells occur arranged in a peculiar
way ; some, smaller, containing chlorophyll,
form a kind of network, the meshes of which
are occupied by large uncoloured cells (see
SPHAGNUM and LEUCOBRYUM).

The margins of the leaves are frequently
serrated ; and the upper surface is occasion-
ally papillose, or covered with rough points.

Magn. 50 diams.

MOSSES.

MOSSES.

Many of them have one or more distinct
nervules, composed of elongated cells, often
not reaching- the apex of the leaf.

The leaves often differ on different parts
of the stem ; and we hence have radical,
cauline, and perichcetial or involucral leaves,
the last ordinarily forming a kind of rosette,
in the midst of which the reproductive or-
gans are produced. SCHISTOSTEGA exhibits
two forms of stems, with two kinds of folia-
ceous structure : the stems which terminate
in a sporange have leaves only at the upper
part, and these arranged in eight rows
standing crosswise on the stem, like ordi-
nary leaves ; the barren stems have two
rows of leaflets arranged in one plane on the
stem, like the leaflets of a compound leaf
(such as that of the Acacias) of Flowering
plants. The stem-leaves of many genera
exhibit wing-like structures, hair-like ap-
pendages, or peculiar forms of curvature
(tigs. 242-246, FISSIDENS); others, like

Fig. 463.

Fig. 464.

Barbula chloronotus.
Fig. 463. Leaf with cellular filaments at the tip. Magn.

30 diams.
Fig. 464. Leaf with cellular filaments crowded on the

midrib, with an awn-like prolongation.

Magn. 20 diams.

certain Barlults (figs. 463-466), have col-
lections of cellular filaments on the upper-
side.

The outer leaves surrounding the repro-
ductive organs are called perichcetial, and
sometimes they form the only envelopes ;
sometimes, however, a few small leaves,
differing very much from the above, form
the immediate envelopes of the archegones ;
and these perigonial leaves, forming the
perigone, are developed after the reproduc-
tive organs themselves (as is the case also

with the perigone of the Hepaticae). The
perigonial leaves either overlap and cover-in
the reproductive organs, or they are keeled
at the base and turned back above, so as to
expose the organs of reproduction (PoLY-
TRICHUM).

The Mosses have no roots, their function

Fig. 466.

Barbula chloronotus.

Fig. 465. Cross-section of 463. Magn. 50 diams.
Fig. 466. Cross-section of 464. Magn. 50 diams.

being performed by root-hairs or rhizoids,
usually brown.

The young reproductive organs consist
of antheridia, and archegonia or pistillidia,
which are found either together (fig. 467),

Fig. 467.

Fig. 468.

Bryum nutans.
Fig. 467. Inflorescence of antheridia and archegonia.

Magn. 25 diams.
Fig. 468. Spermatozoids from antheridia. Magn. 600

diams., the cilia omitted.

or on different parts of the same plant, or on
different individuals of the same species.

Fig. 469.

Mnium arcticum.

Antheridial inflorescence.

Magnified 25 diameters.

To these structures the term inflorescence is
applied. The antheridia occur either with
the archegones in one perigone (fig. 467) or

MOSSES.

[ 512 ]

MOSSES.

in the axils of the upper leaves of the stem,
which terminates in a perigone containing
archegones ; or they have a special perigone
(fig. 4G9), either on the same plant, or on a
different one from that which bears the
archegones. The antheridia are globular,
oval (fig. 467), or elongate membranous
sacs composed of cellular tissue, red or

Fig. 470.

Fig. 471.

Fig. 472.

Fig. 473.

Fig. 470. Cosoinodon pulvinatus. Capsule enclosed in

the calyptra, with the vaginule below.

Magn. 10 diams.
Fig. 471. Orthotrichum Hutchinsii. Capsule covered

by the calyptra, with the vaginule below.

Magn- 10 diams.

Fig. 472. Ditto. Calyptra, Magn. 25 diams.
Fig. 47i>. O. stramineum. Vaginule. Magn. 25 diams.

yellow when ripe, filled with minute cells?
which escape by the bursting of the apex
of the sac ; and these cells exhibit a fibre
coiled in their interior, which circulates
rapidly, even before the expulsion from the
antheridium, and after a time breaks out of

its cell (fig. 468, and PI. 40. fig. 33), and
moves rapidly in the water under the mi-
croscope (see ANTHERIDIA). The anthe-
ridia are generally accompanied by cellular
filaments which have received the name of
paraphyses (fig. 23, p. 57) ; no physiological
office is attributed to these ; but the anthe-
ridia are the male organs.

The archegone of the Mosses (figs. 30, 31
(p. 71), 467), like that of the Hepatic®
(excepting Anthoceros), is a flask-shaped
cellular case, the epigone, containing an
embryonal cell at the bottom of its cavity.
This embryonal cell becomes gradually de-
veloped by cell-division into a conical body
elevated on a stalk, which at length tears
away the walls of the flask-shaped epigone
by a circular fissure, and carries the upper
part upwards as a hood, while the lower
part remains as a kind of collar round the
base of the stalk (figs. 470-472) ; the latter
is termed the vaginula (fig. 473) ; the cap-
like portion carried upwards on the spo-
range is called the calyptra (figs. 470-472).
The sporanye, elevated more or less by the

Fig. 474.

Fig. 475.

Fig. 474. Tayloria serrata. Dimidiate calyptra. Maim

25 diams.
Fig. 475. Funaria hygrometrica. Section of young

capsule, showing the columella. Maan.

50 diams.

development of its stalk (seta or peduncle},
is gradually converted by internal changes
into a hollow urn-like case, usually with a
stalk-like column (columella) running up
its centre (figs. 50, 475), the space between
the central column and the side walls be-
coming filled with free spores, which are
minute cells with a double coat, the outer
of which exhibits elegant markings (see
SPORES). In some cases this hollow case
does not burst naturally, but the spores

MOSSES,

C 513 ]

MOSSES.

escape by its decay (ASTOMUM, fig. 60).
In the ANDIL?EACE.E (fig. 11, p. 41) the
sporange bursts by vertical slits, so as to

Fisr. 476.

Fig. 477.

Fig. 476. Coscinodon pulvinatus. Fragment of peri-

stome. Magn. 100 diams.
Fig. 477. Barbula flavipes. Fragment of peristome.

Magn. 100 diams.

be divided into valves, as in the Junger-
manniese, and there is no column in the
sporange here j but the valves do not sepa-
rate at their summits, and the character of
the leafy stem at once distinguishes these

Fig, 478.

Fig. 479.

Fig. 478. Phascum serratum. Sessile sporange enclosed
by few leaves. Magn. 15 diams.

Fig. 479. Pottia trtmcata. Operculnm separating from
the sporange. Magn. 10 diams.

Mosses from the Hepaticse. The ordinary
ccur.se, however, in the Mosses is the forma-
tion of a horizontal slit near the top of the

sporange, so that the upper part falls off like
a lid (operculum, fig. 479).

The sporange of the Mosses exhibits a
very complex anatomical structure, which
we have not space to enter into very mi-
nutely : it will suffice to state that the
lower part next the peduncle is sometimes
enlarged into a thickened mass, called the
apophysis ; sometimes the peduncle is veiy
long, sometimes very short (Phascum, fig.
478), so that the sporange is hidden in the
perichsete ; finally, the mouth may either
exhibit a smooth edge (fig. 479), or a single

Fig. 480.

Cinclidium arcticum

Part of double peristome, the inner processes united
into a plaited membrane in the centre.

Magnified 100 diameters. . ...

(figs. 476, 477) or double (figs. 483; 484)
fringe of veiy variously constructed teeth,
which are of great service in discriminating
the genera. When the mouth of the spo-
range is naked, the Mosses are called gym-
nostomom, when furnished with only a
single row of teeth haploperistomous. When
a double peristome exists, the outer con-
sists of teeth, the inner of processes or cilia
(fig. 483) or of both (E-rt/um). The teeth
sometimes arise directly from the mouth of
the sporange, sometimes are seated on a
basal membrane, sometimes connected to-
gether irregularly (FUNAKIA, fig. 259, p.
342), or by regular bars (GUEMBELIA, fig.
291, p. 366), or the whole of the inner circle
may be conjoined entirely (BUXBAUMIA,
iig. 93, p. 126) or at the tips (fig. 480) into
a membrane, or by a number of cross bars
into an open trellis (fig. 484). . The. outer
rows of teeth are continuations of the inner
layers of tissue of the sporange (fig. 481) ;

2L

MOSSES.

[ 514 ]

MOSSES.

where an inner circle occurs they are con-
tinuations of the spore-sac ; the outer wall
of the sporange is, as it were, continued by
the operculum. Ordinarily these do not
separate directly from each other when the
lid falls off, since one or several layers of
elastic cells, forming a ring (annulus, fig. 482)
round the mouth, split out from between
the sporange and its lid, and cause the latter
to fall off.

The spores are developed in a distinct
epore-sac, which has one layer next the wall
of the capsule, and an inner layer next the

Fig. 481.

Fig. 482.

Fig. 481. Kacomitrium fasciculare. Section of margin
of sporange, with a tooth of the peristome.
Mogn. 100 cliams.

Fig. 482. Bryum ctespiticium, annulus. Magn. 100 diams.

Fig. 483. Orthotrichum diaphanum. Portion of double
peristome, the outer composed of teeth,
the inner of cilia. Magn. 50 diams.

Fig. 484.

Neckera antipyretica.
Double peristome, the inner composed of teeth united
by cross bars, forming a trellis.

Magnified 100 diameters.

columella. The top of the columella ex-
pands into a kind of pseudo-operculum in
Polytrichum. In Phascaceae the columella
is absorbed.

Allusion has been made to the sexual im-
port of the antheridia and archegonia. In
the reproduction of the Mosses the spores
produce a confervoid filament or protonema,
from the sides of which the young plants
with stem and leaves shoot ; and on these
the antheridia and archegonia are formed.
From the embryo-cell of the fertilized
archegonium arises the sporogonium, in
which the spores are formed.

The Mosses exhibit a variety of forms of
vegetative multiplication. The lower part
of the stem often sends out horizontal
branches, which root and produce buds
(fig. 485), from which arise new leafy stems ;

Fig. 486.

Polytrichum undulatum.

Creeping filaments with innovations.

Magnified 5 diameters.

and in this way, patches of moss frequently
increase to a great size.

They also produce confervoid filaments,
which exhibit tuberous thickenings, a form
of gemma (figs. 488, 489), which may be
detached from each other like bulbils, so as
to propagate the plants without any sexual
reproductive organs.

The protoplasm of these confervoid fila-
ments also forms Amoeboid bodies, and
gonidia or ciliated zoospores (Hicks).

Gemma or minute cellular tubercles,
capable of development into new plants,
are likewise met with in other situations,
as in the axils of leaves, on the surface, the
margins (fig. 490), or at the tips (figs. 486,
487) of the leaves or the stems (fig. 491) :
these are formed of only a few cells at the
time they fall off, and illustrate well the

MOSSES.

[ 515 ]

MOSSES.

Fig. 486.

Fig. 487.

Orthoti'ichum phyllanthum.

Leaves with gemmae at the tips.

Magnified 25 diameters.

independence of the individual cells forming
the organs of these plants, where, tinder
peculiar circumstances, a single cell of the
tissue may be developed so as to lay the
foundation of a new plant.

In the following arrangement of the
Mosses we follow Miiller. The order Mus-

Fig. 488.

caceae is first divided into two suborders
according to the habit of growth :

ACROCARPI. Mosses with the fruit-
stalk terminating the stem, or short special
branches (Cladocarpi).

PLEUROCARPI. Mosses with the fruit-
stalk produced only from lateral buds.

Synopsis of the Families.
ACROCARPI.

* Schistocarpi. Capsule without a lid
(operculuni), opening by longitudinal
fissures.

ANDRJEACE^:. Capsule splitting into
four valves.

** Cleistocarpi. Capsule without a lid,
bursting open irregularly.

BRUCHIACE^. Cells of the leaf (areola-
tioti) parenchymatous, looser at the base,
not papillose, dense.

PHASCACEJE. Areolation of the leaf
parenchymatous, dense, filled with chloro-
phyll, more or less papillose.

EPHEMERE-E. Areolation of the leaf
parenchymatous, everywhere lax, not papil-
lose.

Fig. 490,

Fig. 491.

Hedwigia ciliata.

Creeping filaments with tuber-like gemmae.
Fig. 488, magnified 50 diameters.
Fig. 489, magnified 20 diameters.

Fig. 490. Orthotrichum Lyellii. Leaves with mar-
ginal gemmae. Magn. 50 diams.

Fig. 491. Aulacomnium undulatum. Gemmae in the
place of the capsule. Magn. 20 diams.

2L2

MOSSES.

[ 610 ]

MOSSES.

*** Stegocarpi. Capsule bursting by a lid.

Distichophylla. Leaves arranged in two
straight roios.

a. Leaves regularly vertical.
SCHISTOSTEGE^E.

b. Leaves regularly subvertical.

DBEPANOPHYLLEJE.

c. Leaves horizontal.

DJSTICHIACE^:. Areolation of the leaves
parenchymatous, minute ; leaves without
appendicular laminae.

FISSIDENTEJE. Areolation of the leaves
parenchymatous ; leaves produced into ap-
pendicular laminae at the back and point.

Polystichophylla. Leaves arranged in
three or more straight alternating
rows.

a. Leaves exhibiting narrow green cells, forming a reti-
culation between larger diaphanous cells.

LEUCOBBYACE^E. Leaves composed of
several layers of columnar, empty, paren-
chymatous cells; the 'intercellular' green
cells three- to four-angled, interposed be-
tween the empty cells in a single curved
row.

SPHAGNACE^;. Leaves composed of a
sir.gle stratum of empty prosenchymatous
cells, with intercellular green cells interposed
between all the empty cells. Cladocarpous,
branches fasciculate.

b. Leaves without ' intercellular ' cells.
a. Leaves not papillose.

1. Loosely areolated.

FUNABIOIDEJE. Areolation of the leaf
parenchymatous, lax, containing much chlo-
rophyll.

DISCELTACE^. Areolation of the leaves
rhomboid-prosenchymatous, destitute of
chlorophyll, empty, fuscescent.

BUXBAITMIACEJE. Areolation of the leaf
hexagonal or polygonal, very minute, dark-
coloured, destitute of chlorophyll.

2. Densely areolated.

MNIOIDE^:. Areolation of the leaf in
parallelograms at the base, round-hexago-
nally parenchymatous towards the apex ;
very full of chlorophyll, or more frequently
thickened (very rarely papillose).

BBYACE^. Areolation of the leaf prosen-
chymatous, ordinarily rhomboidal, abound-
ing with chlorophyll.

DICBANACEJE. Cells of the leaf prosen- '

chymatous, very often intermixed with
parenchymatous cells (rarely scabrously pa-
pillose), alar basilar cells ordinarily crowded
and ventricose, or flat and much more
loosely reticulated than the upper cells.

LEPTOTBICHACE^S. Cells of the leaf
rhombic at the base, rectangular or both
mixed further up, smooth, without proper
alar cells.

b. Leaves papillose.

BABTBAMIOIDE^:. Cells of the leaves
parenchymatous, square, ordinarily nodu-
lose or scabrous with papillae at the trans-
versal sides, never opaque.

POTTIOIDEJE. Cells of the leaves paren-
chymatous, square, ordinarily covered on
all sides with papillae above 'the base, but
smooth and pellucid at the base.

DIPHYSCIACEJE. Leaves of two kinds ;
the cauline with the cells densely hexa-
gonally parenchymatous, abounding with
chlorophyll, the perichaetial leaves with the
cells destitute of chlorophyll and more
loosely reticulated.

PLEUROCARPI.

Distichophylla. Leaves arranged in
two opposite rows.

PHYLLOGONIACEJE.

Tristichophylla. Leaves (twanged in
three rows, appearing like three, erect,
of two forms.

HYPOPTEBYGIACEJE. Cells of the leaf
everywhere prosenchymatous, equal.

Polystichophylla. Leaves arranged in
four or more rows.

MNIADELPHACFJE. Cells of the leaf
parenchymatous, Mnioid.

HYPNOIDEJE. Cells of the leaf prosen-
chymatous, rhombic or rounded.

feiBL. Hooker, Taylor, and Wilson, Bryol.
Brit. ; Bruch and Schimper, Bryol. Eur. •
Schimper, Cor. Bryol. Eur. 1855; Flora,
1850, 681 ; Hedwig, Theoria general. ; Bri-
del, Bryol. Universa ; Miiller, Syn. Muse,
frond. ; Dillenius, His. Muse. ; Lanzius-
'Beninga, Nova Acfa, xxii. 555 ; Hofmeister,
Vergl. Unters. 1837 : Ber. Sachs. Gesell
Wws. 1854; Flora, 1855, 434; Valentine,
Linn. Tr. xviii. 490; Hicks, Linn. Tr. xxiii.
1862,567; Braithwaite, Mosses; Stevenson,
Myc. Scot. 1879 ; Tripp, Br. Mosses, fgs. of
spec. ; Hervey, American Sea-mosses, 1881 ;

MOTH, CLOTHES.

[ 517 ]

MOUTH.

Sachs, Bot. 359 ; Janczewsky, Bot. Zeit.
1872.

MOTH, CLOTHES. See TINEA.

MOTHER CELL, or PAHENT CELL, the
term commonly applied to the cell in the
interior of which a new generation of cells
is developed.

MOTHER-OF-PEARL. See SHELL.

MOUGEO'TIA.— A genus of Zygnema-
cese (Confervoid Algas), distinguished by
the conjugation of the filaments taking place
without the formation of transverse pro-
cesses, the conjugating filaments being ge-
niculately bent. There is still obscurity as
to the mode of reproduction of the plants of
this genus. According to Vaucher, a spore
is formed in one of the conjugating cells,
without transfer of contents, and this, ger-
minating in situ, breaks out from the pa-
rent cell. Hassall says the plants are re-
produced by zoospores ; this has been con-
firmed by Kiitzing, who, together with
Itzigsohn, has observed the formation of
small rounded re sting-spores in the joints,
which underwent segmentation and deve-
loped a number of smaller cells, the ultimate
fate of which was not observed. All this
tends to prove that the reproduction agrees
with that of Spirogyra, where we have : —
1. large conjugation-spores, sometimes ger-
minating in situ, producing iii some cases
new filaments, in others zoospores ; 2. zoo-
spores produced immediately from the con-
tents ; and 3. what appeared to be encysted
forms of these (see SPIROGYRA).

M. genvfvexa, Ag. (fig. 139, p. 205). The
cells are about 1-720" in diameter in
large specimens (M. major, Hass.), and
about three or four times as long ; in smaller
specimens (M. gemtflexa, Hass., M. gracilis,
Kiitz.) the diameter is about 1-200", the
length of the cells five or six times as great.

In fig. 139 the lowest filament does not
belong to the genus: but the method of
conjugation of Mougeotia is seen in the one
above.

M. leer's, Archer, is an Irish form.

BIBL. Vaucher, Conf. d'eau douce, 79,
pi. 8; Hassall, Alg. 171, pi. 40; Kiitz. Sp.
Alg. 43 5 Tab. Phyc. v. pis. 1-3 and 36;
Itzigsohn, Bot. Zeit. xi. 081, 1853 ; Rabenh.
Alg. iii. 255 ; Archer, Qu. Mic. Jn. 1867.

MOULDS and MILDEWS. — These
names are generally applied indifferently to
a multitude of Hyphomycetous, Phycomy-
cetous and Coniomycetous Fungi; but some
of the more common ones are especially
distinguished. Thus ordinary ' blue mould '

of cheese, &c. is ASPERGILLUS glaucus\
another still more common blue or green
mould is PENICILLIUM glaucum ; various
species of OIDIUM and ERYSIPHE are known
as the mildews of the Hop, Vine, Rose,
&c. The mildew of wheat is PUCCINIA
graminis.

MOUNTING. See PRESERVATION.

MOUSE, HAIR OF (PL 1. fig. 3 ; PL 29.
figs. 27, 28). See HAIR OF ANIMALS and
TEST-OBJECTS.

MOUTH. — The mucous membrane of
the mouth, which becomes continuous with
the skin at the lips, is furnished with very
numerous conical or filamentous papilla3
resembling those of the skin, sometimes
simple, at others branched, and a number
of mucous glands.

Its epithelium is of the pavement kind,
consisting of several layers of delicate cells ;
these are roundish in the deeper, flattened
and polygonal in the superficial layers.

Epithelial cells of the mucous membrane of the human
mouth : a, large, 6, smaller cells ; c, one with two nuclei.

Magnified 350 diameters.

The glands, distinguished, according to
their situation, as the labial, the buccal, and
the palatal glands, are rounded, about 1-36

MOUTH.

[ 513 ]

MUCEDINES.

to 1-6" in size, and open by short excretory
ducts into the mouth. They consist of
glandular lobules enveloped in areolar tissue
with elastic fibres, the whole being sur-
rounded by a firmer portion or capsule, and
a branched duct. The lobules are composed
of a number of convoluted canals or lobular

Fig. 493.

Human racemose mucous gland from the floor of the
cavity of the mouth, a, areolar coat ; 6, excretory duct ;
c, glandular caeca; d, lobular ducta.

Magnified 50 diameters.

ducts, with simple or compound caeca or
glandular vesicles, each consisting of a

Fig. 494.

The ducts of the lobules have a coat of
connective tissue, with networks of fine
elastic fibres, and a single layer of cylindrical
epithelial cells.

Fig. 495.

Diagram of two lobular ducts of a mucous gland, a, common duct ;
6, lobular branch; c, glandular vesicles in situ; d, the same separated,
and the ducts unfolded.

Magnified 100 diameters.

basement membrane and a single layer of
angular epithelial cells. The latter separate
very readily; and then the caeca appear filled
with a granular mass-

Two glandular vesicles of a human racemose mucous
gland, a, basement-membrane; b, epithelium, side
view ; c, the same in surface view.

Magnified 100 diameters.

The mucous liquid of the mouth con-
tains, in addition to detached epithelial
cells, very transparent corpuscles, about
1-2000 to 1-1500" in diameter, consisting
of a delicate cell-wall, a nucleus, with a
number of minute moving molecules. We
have figured these among the TEST-OBJECTS
(PI. 1. fig. 5). They are called mucous or
salivary corpuscles. Kolliker regards them
as a form of exudation corpuscles : and this
view is probably correct ; for they may occur
in the secretion of any mucous surface, and
have no special connexion with the salivary
glands : we have found them in myriads
in the urine.

The secretion of the mouth frequently
contains very slender filaments of a fungus
(LEPTOTHRIX), with species of Monas and
of Vibrio.

BIBL. Kolliker, Mik. An. ii. ;
Sebastian, Rech. An. s. I. gland,
labial. ; Webb, Qu. Jn. Med. Sri.
1857; y?*Td,Todcr8Cycl.An.&c.'j
Klein in Strieker, Hist. i.

MUCEDINES.— A family of
Hyphomycetous Fungi, forming
moulds and mildews upon living
or decaying animal or vegetable
substances, and contributing to
their decomposition, character-
ized by a flocculent mycelium
bearing erect, continuous or sep-
tate, simple or branched, tubular
p«llucid filaments, terminating
in single spores or strings of spores, which
soon separate from each other, and lie
among the filaments of the mycelium.
This tribe includes a number of the most

MUCEDINES.

[ 619 ]

MUCEDINES.

interesting of the microscopic fungi, noted
for their destructive influence upon organic
bodies which they attack. The species of
Botrytis, Oidium, &c. spread with won-
derful rapidity as mildews over the herba-
ceous parts of vegetables and moist vege-
table substances generally; in the former
situations their spores enter the stomata,
their mycelia ramifying among the subjacent
cells, and carrying decomposition and decay
into all the soft structures. They are most
abundantly developed in a close, damp at-
mosphere. The mycelia of other kinds, as
of PENICILLIUM, growing in liquids con-
taining organic matter, or upon decaying
vegetable substances, produce remarkable
chemical decompositions, causing a fer-
mentation of the medium in which they
exist.
See PENICILLIUM and FERMENTATION.

Synopsis of British and nearly allied Genera.

A. Fertile filaments (pedicels) simple or
branched, terminating in single spores or
a very short row.

* Spores simple.

Botrytis. Pedicels erect, septate,
branched ; branches and branchlets septate ;
spores solitary, on the tips of the branch-
lets, which are either racemose, umbellate,
cymose (Polyactis), paniculate, verticillate
(Acrostalagmus), spicate (Haplaria) or ca-
pitate.

Peronospora. Like Botrytis, but the
pedicels without septa; often producing
resting-spores.

Verticillium. Pedicels erect, septate, with
whorled branches terminating in a solitary
spore or a short row of spores.

Acremonium. Pedicels short, subulate,
branches from a horizontal filament, bearing
single smooth spores.

Zyyodesmus. Like the last, but with
echinulate spores.

Oidium. Pedicels simple, short, erect,
clavate, septate, bearing usually one, some-
times two more or less oval spores.

Fasidium. Pedicels very short, pulvinate.
Spores elongate, fusiform.

Menispora. Pedicels erect, septate, bear-
ing fusiform or cylindrical spores, at first
joined in bundles.

Sceptromyces. Pedicels erect, geniculate,
verticillately branched ; branches short, race-
mose ; spores in grape-like bunches.

** Spores septate.

Brachycladium. Pedicels branched above,
septate, moniliform; branches and branchlets
forming a sporiferous capitulum; spores
transversely septate.

Trichothecium. Pedicels interwoven in
tufts, the central erect, fertile ; spores acro-
genous, didymous, free, commonly loosely
heaped together.

Cephalothecium. Pedicels simple, con-
tinuous, bearing a terminal head of didymous
spores.

B. Erect filaments (pedicels) terminating in
strings of spores.

* Spores simple.

Penicillium. Pedicels erect, septate, peni-
cillately branched above ; branches and
branchlets septate ; strings of spores attached
to the tips of the branches.

Sporotrichum. Pedicels erect, simple or
slightly branched, septate and articulate,
articulations remote, inflated ; spores simple,
usually found collected in heaps among the
filaments.

Briarea. Pedicels erect, septate, with
terminal moniliform chains of spores,
crowded into a head.

Gonatorrhodon. Pedicels erect, septate,
with chains of spores in a terminal head
and in whorls at the joints.

** Spores septate.

Dendryphium. Pedicels erect, septate,
unbranched ; strings of spores attached in a
bunch to the apex ; spores septate.

Dactylium. Pedicels erect, septate,
branched above; strings of septate spores
attached singly or in pairs to the apices of
the branches.

C. Fertile filaments (pedicels} inflated at
the tips or at various points in their
length, with projecting points or warts
on the inflations, bearing

* Simple spores.

Aspergillus. Pedicels continuous, erect,
simple filaments, inflated into a little head
at the summit; bearing moniliform chains of
spores, crowded into a capitulum.

Rhinotrichum. Pedicels erect, septate,
sometimes sparingly branched, the apices
clavate, cellular, bearing scattered points
supporting simple spores.

MUCOK.

[ 520 ]

MUCOIl.

Papulaspora. Pedicels, short lateral
"branches from a creeping filament, termi-
nating in cellular heads beset with simple
spores on the areolae.

Rhopalomyces. Pedicels erect, not septate,
terminating in cellular heads, with simple
spores on the areolae.

Stachylidium. Pedicels erect, articulated,
whorled-branched above ; branchlets geni-
culate and articulate ; spores subpedicellate,
accumulated in little capituliform heads
inserted at the tips of the branches.

Gonatobotrys. Pedicels erect, septate,
with joints swollen at intervals, the swollen
joints bearing globular heaps of spores on
short spines spirally arranged.

Acmosporium. Pedicels erect, septate,
branched above; branches and branchlets
forming a cyme, thickened at the apex, and
furnished with globular canitules covered
all over with points j spores simple, attached
on the points of the capitules.

Haplotrichum. Pedicels erect, septate,
terminating above in a continuous, simple,
solitary, sporiferous head ; spores simple.
, Actinocladium. Pedicels erect, septate,
umbellately branched at the summit ; spores
simple, accumulated at the tips of the
branches.

Botryosporium. Pedicels erect, septate,
with short spine-like branchlets above, spi-
rally. arranged, and terminating in four or
five short points, which, support globular
heads of spores.

**

Spores septate.

Arthrobotrys. Pedicels simple, septate,
with joints swollen at intervals, the swollen
joints clothed with spines bearing didymous
spores, which are collected into globular
heaps.

Some of the species are mere conditions
of perfect Fungi, as Hypoxylon and Claviceps.

In several genera, sexual union like that
in Tuber and Peziza takes place.
; MU 'COR, Micheli. — A genus of Mucorini
(Phycomycetous Fungi), forming a common
mould on paste, decaying fruits, or other
vegetable matters. The general character
is that of an interwoven mass of hori-
zontal branched filaments, sending down
little root-like ramules, and pushing up
erect, not septate, fertile filaments, which
branch at the base in a stoloniferous man-
ner, and thus form loosely grouped tufts.
At the summit of the erect filaments, a
globular vesicle is formed, which soon be-

comes cut oft' by a septum. Its contents
become divided into a large number of
spores ; and the septum at the base becomes
meanwhile pushed up or protruded into the
centre of the vesicle so as to form a kind of
" core," called the columella. After a time
the vesicle (peridiole) bursts and discharges

Fig. 496.

Fig. 497.

Mucor ]Vf u< cdo.
(Aseophoia foim.)

Fig. 496. Nat. size, growing on a leaf.
Fig. 497. Single fertile filaments, with the columella
collapsed, and fallen like a cap over the end. Magn. 50

its spores ; the pressure of the turgid colu-
mella apparently hastens the bursting. The
dehiscence takes place either by a circular
slit just above the base of the columella,
leaving this alone, surrounded by a narrow
ragged collar (Mucor), or the peridiole
bursts above and disappears by solution,
and the columella collapses upon the pedicel
(Ascophora, fig. 497). The membrane of
the peridiole of M. tilucedo, and perhaps of
other species, is clothed with minute spines.
The erect filament is sometimes simple,
sometimes branched. It has been conjec-
tured, though on what grounds is uncertain,
that the columella may become converted
into a second peridiole, by being shut off by
a septum which is converted into a new
columella.

It has been imagined that ACHLYA is
only an aquatic form of Mucor] and this-
seems not improbable ; however, the expe-

MUCOK.

[ 521 ]

MUCOKINL

ri merits we have made on this point have
hitherto given negative results.

The species of Jfrucor described by authors
are pretty numerous; but we think consider-
able allowance for variation should always
be made in this genus. RHIZOPUS, Ehr. =
Mucor when distinctly stoloniferous. It
seems very doubtful whether HYDROPHORA
should be separated from Mucor. Conju-
gation takes place in one or two species.

* Fertile filaments simple.

M. Mucedo, L. (figs. 496, 497). Myce-
lium byssoid, peridiole and spores globose,
at first white, ultimately blackish. (This
includes Ascophora Mucedo, Tode.) Ex-
tremely common. Sowerby, Fungi, pi. 378.
fig. 6 ; Greville (Ascophora} ,'Cn/pt. Fl. pi. 269.

M. caninus, Pers. Mycelium byssoid,
peridiole globose, ultimately yellow or fer-
ruginous ; spores globose or elliptic. Very
common on excrement of dogs and cats in
wet weather. Grev. Sc. Crypt. Fl. pi. 305.

M . fusiger, Lk. Mycelium byssoid. Peri-
diole globose, ultimately black ; spores spin-
dle-shaped. On decaying fungi.

M. clavatus, Lk. Mycelium byssoid. Cla-
vate apices of the fertile filaments simply
penetrating the globose peridiole ; spores
globose, at first white, then brown, at
length black. On rotten pears ; possibly
only a state of M. Mucedo or the following.

M. amethysteus. Mycelium thick, white,
closely interwoven. Peridiole at first white,
then pale yellow, then crystalline and pure
violet, finally violet-black or brownish j
spores globose, filled with globose spori-
dioles (?). Fertile filament 1-40" high.
On rotten pears with the foregoing.

M. delicatulus, Berk. Mycelium form-
ing a thin velvety stratum. Very minute ;
fertile filaments short ; peridioles globose, pale
yellow ; spores globose. On rotting gourds.

M. succosus, Berk. Mycelium forming
small, pulvinate, yellow, spongy masses.
Peridiole very minute, globose, yellow, at
length olive ; columella minute. On dead
shoots of Aucuba. Berk. Ann. N. H. vi.
pi. 12. fig. 15.

** Fertile filaments branched.

M. ramosus, Bull. Mycelium woolly.
Fertile filaments racemose. Peridioles glo-
bose, yellow, then bluish-grey or reddish-
brown. On rotting fungi. Bulliard, pi. 480.
fig. 3.

M. suUilissinms, Berk. Mycelium creep-
ing, filaments exceedingly slender. Fertile

filaments branched, the short patent branches
each terminating in a globose peridiole ;
spores oblong, elliptical. A mildew of
onions. Berk. Hart. Jn. iii. 97. figs. 1-5.

BIBL. Berk. Br. Flora, ii. pt. 2. 332;
Ann. N.H.vi. 433 ; Hort. Jn. iii. 91 ; Fries,
Summa Veg. 487 ; Syst. Myc. iii. 318 ; Fre-
senius, Beitr. z. Mycologie, heft i. 4, 1850 ;
v. Tieghem, Ann. Sc. N. 1875, i. 5 : Brefeld,
Flora, 1873.

MUCORI'NL— A family of microscopic
Phycomycetous Fungi, constituting the
moulds, &c. common on most decaying
vegetable and animal substances, consisting
of a filamentous mycelium, forming flocks
and clouds in or on decaying matters, bear-
ing vesicles, on erect pedicels or sessile,
filled with minute sporules, discharged by
the rupture of the vesicles (peridioles).
These plants correspond among the theca-
sporous Fungi to the Mucedines among the
acrosporous or free-spored orders. The
peridiole consists of the terminal cell of an
erect filament, enlarged like the head on a
pin, into a globular vesicle. At first the
cavity of this vesicle communicates with
that of the pedicel ; but a septum is soon
formed ; in some genera this septum is flat,
in others projecting into the interior of the
peridiole like the " punt" of a bottle, form-
ing a hemispherical or cylindrical columella.
While this columella rises in the peridiole,
the latter becomes filled with spores, form-
ing thus a polysporous sporange; and it
bursts to let them escape.

The manner of bursting of the sporange
and the form of the central column vary
much, and afford generic characters. Thel-
actis presents a remarkable peculiarity : each
filament terminates in a sporange containing
a great number of spores, while at its base
it gives origin to whorls of branches, the
terminal cells of which remain sterile.

Syzygites exhibits conjugation of its
branches, like that of the Zygnemaceze.

Some observations of De Bary tend to
show that the genus Eurotium only repre-
sents certain conditions of Aspergillus. In
some cases the lower threads are enor-
mously developed, where, from excessive
moisture, the fruit cannot be produced.
Two different forms of fruit occasionally
occur in the same thread, as in Ascophora
elegans.

Synopsis of British Genera.
Phycomyces. Peridiole pear-shaped, se-
parated from the apex of the erect pedicel

MUCOUS CORPUSCLES. [ 522 ]

MUSCA.

by ail even joint; opening by an umbilicus.
Spores oblong, very large. Filaments cses-
pitose, tubular, continuous, and shining.

Hydrophora. Peridiole subglobose, mem-
branous, dehiscent, at first crystalline, aque-
ous, then turbid, and at length indurated,
persistent. Columella absent; spores simple,
conglobated.

Mucor. Peridiole subglobose, separating
like a cap (leaving an annular fragment
attached) from the erect, simple, continu-
ous pedicel, or bursting irregularly ; colu-
mella cylindrical or ovate, spores simple.

(?) Acrostalagmus. Peridioles globose,
with a columella, at the points of doubly
verticillate branches from an erect pedi-
cel.

Pilobolus. Peridiole globular, separating
like a cap from the short stalk composed of
a single cell, attached on a unicellular rami-
fied mycelium ; columella conical ; spores
very numerous, free in the peridiole.

Syzygites. Filaments erect, simple, very
much branched above, branches and branch-
lets di- or trichotomous, fertile branches
forcipate, bearing pairs of opposite internal
clavate branches, which subsequently coa-
hsce.

MUCOUS CORPUSCLES. See MOUTH.

MUCOUS MEMBRANES.— Those in-
ternal canals and cavities of the body which
open externally, as the alimentary canal,
bladder, &c., are bounded by what may be
regarded as internal prolongations of the
skin, called mucous membranes.

They consist of four layers: — 1, an inner-
most or epithelial layer, corresponding to
the cutaneous epidermis ; 2, a subjacent
structureless basement membrane, which is
not always separable and demonstrable or
present; 3, a layer of variable thickness,
consisting of connective and elastic tissue,
well supplied with blood-vessels and nerves,
often containing numerous small glands,
frequently furnished with conical or filiform
processes termed papillae or villi, and some-
times traversed by muscular fibres. These
three layers form the proper mucous mem-
brane ; and are supported by, 4, an outer-
most submucous layer or coat, composed of
the same elements as the last, but much
more lax in structure, and frequently con-
taining fatty tissue.

The mucous membranes are usually very
vascular; and injected preparations of them
are very beautiful, and to some extent cha-
racteristic.

The size and form of the epithelial cells

are to a certain extent also characteristic,
especially those of the uppermost layer;
and a knowledge of the peculiar structure
in individual cases is of use in determining
the source of morbid mucous products mixed
with epithelial cells.

See the special articles.

MUCRONEL'LA, Hincks, = Zepr«Zmpt.
Zoary incrusting ; cells with a rounded or
semicircular orifice, and an anterior tooth.
Several species; on rocks, shells, and sea-
weeds. (Hincks, Polyz. 360.)

MUCUS. — Natural mucus contains no
essential morphological elements. As ordi-
narily met with, it often, however, exhibits
some epithelial cells, mucous corpuscles,
and numerous granules; and the peculiar
mucous matter has a striated or fibrous
appearance, mostly produced artificially.
The abnormal elements are principally those
of inflammation.

BIBL. See CHEMISTRY, ANIMAL.

MUD. — The organisms found in mud are
very numerous ; they consist principally of
Diatomaceaa and other minute Algae. The
surface of mud is often covered with yel-
lowish or greenish layers, composed almost
entirely of these organisms. The most
beautiful and most numerous forms of Dia-
tomacese are found in the mud of sea-water,
or that of tidal rivers. On exposing a bottle
of mud and water to the light, they will
rise to the surface of the mud, some adher-
ing to the side of the bottle next the light,
and can then be easily separated. The sur-
face of freshwater-mud frequently appears
of a blood-red colour, from the presence of
Tubifex rtvulonim.

M'UREX'IDE. See AMMONIA, PURPU-

RATE OF.

MURIATE OF AMMONIA. See AM-
MONIA, HYDROCHLORATE OF.

MU'RIFORM. — The term applied to
flattened six-sided cells placed one above
the other in one or more rows, like bricks
in a wall.

MU 'SA, Tournef. — A genus of Musacere
(Monocotyledonous Flowering Plants), com-
prising the Bananas and Plantains. The
fibro-vascular bundles of Musa aftbrd ex-
amples of spiral vessels with numerous
spiral fibres (see SPIRAL STRUCTURES).
Musa textilis affords the fibre called Manilla
hemp (see PI. 28. fig. 7). See FIBROUS
STRUCTURES.

MUS'CA, Linn. — A genus of Dipterous
Insects, of the family Muscidae.

Among the well-known species, all of

MUSCACE^E.

[ 523 ]

MUSCLE.

which have been formed into new genera,
we may mention :

Musca domestica, L., common house-fly.
Third joint of antennae thrice the length of
the second ; style plumose, eyes reddish
brown, front of head white, the rest black ;
thorax blackish grey with four longitudinal
black bands, abdomen blackish brown above,
with blackish elongated spots, pale yellow-
ish brown beneath.

M. carnaria, L. (Sarcophaga, Meigen),
the flesh-fly. Antennae feathery; head
golden-yellow in front, eyes reddish ; thorax
grey, with black longitudinal lines; abdomen
black, with four square white spots on each
segment ; all the body strewed with black
hairs. Viviparous, 1-2" long.

M. Ctesar, L. (Lucilia, Donov.). No
spots, abdomen green, with a metallic lustre.

M. vomitoria, L. (CaUmhorat Donov.),
bluebottle or blow-fly. Head yellowish,
golden or white, eyes brown ; thorax black ;
abdomen shining blue with black stripes
and long black hairs.

The larvae are known as gentles. The
ova or larvae are deposited upon animal or
vegetable substances, mostly in a state of
decay, upon which they live.

Several parts of the species of Musca are
of general microscopic interest, — as the
proboscis (PI. 33. fig. 29) with its two fleshy
lobes (c), kept expanded by a beautiful and
elastic framework of modified tracheae ; the
setae or lancets (6), which are modified
maxilla, sometimes rudimentary, with their
palpi (a) at the base ; the remarkable an-
tennae (PI. 33. fig. 20) ; the elegant tarsus
(PL 34. fig. 7 a), with its terminal spine,
pulvilli (figs. 7, 8 & 9) and claws ; and the
rudimentary wings or halteres (INSECTS,
p. 432).

Musca pumtlioms (Chlorops, Meig.) de-
posits its eggs in the young wheat-grain,
which is consumed and destroyed by the
larvae.

Many other members of allied families of
Diptera, commonly known also as flies, are
of microscopic interest, on account of their
oral setae or lancet-like organs.

BIBL. Westwood, Intr.; Macquart, Ins.
Dipt. ; Meigen, Syst. zweiftiig. Insect. ; Keller,
Stubenfliege ; Suffolk, Mn. Mic. Jn. i. 331 ;
Lowne, on the Bloic-fly.

MUSCA'CE/E. See MOSSES.

MUSCARDINE. — A disease in silk-
worms, in which the whole of the sebaceous
matter is exhausted, and the blood greatly-
altered, by a species of mould, Sotrytis

I bassiana, which is perhaps too near Botrytis

! diffusa, Grev. A few of the spores placed
on the back of a healthy silkworm are
sufficient to impregnate the whole body.
It takes its name from the resemblance of
the diseased caterpillar to a peculiar kind
of pastile.

BIBL. Balsamo, Gaz. de Milan, 1835 j
Bibl. It. xxix. 1835; Robin, Veg. Par. 560;
Guerin, Seric. 1849, 1850, 1851.

MUSCLE. — Muscular tissue forms the
greater portion of the flesh of animals.

It occurs in two principal forms ; one of
which is termed organic, unstriated, or
unstriped muscle; the other, voluntary,
striated, or striped muscle.

Unstriated muscle. — This consists of more
or less elongated, somewhat spindle-shaped,
narrow fibres (p. 74, fig. 35), having the
import of cells, and hence often called fibre-
cells ; they are, however, solid. Each con-
tains an elongated nucleus, brought to light
by acetic acid, and exhibiting a reticular
appearance. The fibres are of variable
length (from about 1-580 to 1-250"), and
1-5000 to 1-3500" in diameter. They oft*':,
appear longitudinally fibrous within; and
the cell -wall is transversely wrinkledk
They sometimes exist singly in the midst
of connective tissue ; at others they are
united into rounded or flattened bundles,
and surrounded by an imperfect kind of

I sarcolernma, composed of connective tissue

i with elastic fibres.

Fig. 498.

Unstriated muscular fibres from the casophagus of a
pig, after treatment with dilute nitric acid.
Magnified 10 diameters.

They occur most abundantly in the hol-
low viscera, as the stomach, the intestines,
the bladder, and the uterus ; but they also
exist in other situations, as the spleen

MUSCLE.

MUSCLE.

trachea and bronchi, the dartos, the arteries,
veins, and lymphatics, the prostate gland,
fallopian tubes, urethra, villi of the small
intestines, the skin, iris, and beneath the
long-pleura, &c.

Striated muscle. — The structure of striated
is more complex than that of unstriated
muscular tissue. It consists of a number
of very slender fibres, called fibrillae, con-
nected into bundles, termed primitive bun-
dles or fasciculi, each of which is enclosed
in a sheath or sarcolernma. The primitive
bundles are again united into secondary and
tertiary bundles, the whole being bound
together by a mass of connective and elastic
tissue surrounding each of them, and form-
ing the perimysium. This arrangement is
best seen in a transverse section (fig. 499).

Fig. 499.

Transverse section of a portion of the stern o-c)eido-
ma'toideus: a, outer perimysium; ft, inner perimy-
eium ; c, primitive and secondary muscular bundles.

Magnified 50 diameters.

Fig. 500.

. Transverse section of the muscular fibres or primitive
bundles of the human gastrocnemius: a, sarcolemma
and interstitial connective tissue ; b, section of fibrillae
and intermediate substance.

Magnified 350 diameters.

The primitive bundles are from about
1-1000 te 1-200" in diameter, and of a
rounded or polygonal form (fig. 500). Their
surfaces are marked by a number of trans-
verse striae, which forms the most charac-
teristic appearance of the tissue. They also
exhibit irregular longitudinal striae, which
are the indications of the component fibrillae
(PI. 22. fig. 35).

Fig, 501.

1 j

Portion of a primitive bundle treated with acetic
acid: a, sarcolemma ;6, single nucleus; c, twin nuclei
surrounded by granules of fat.

Magnified 450 diameters.

The sheath or sarcolemma, when separated
from the muscular substance by treatment
with water, acetic acid, and alkalies, in
which it is insoluble, forms a structureless,
transparent and smooth membrane. It is
perhaps most easily seen in the muscle of
fishes by simple dissection (PL 50. fig. 18).
On its inner side are numerous spindle-
shaped or lenticular nuclei (fig. 501).

The ultimate or primitive fibrillae in man
are about 1-20,000" in diameter, and each
exhibits numerous regularly alternating
light and dark portions (PL 22. fig. 36 b) ;
the relative positions of the two may, how-
ever, be made to change by altering the
focus ; but the dark bands are more highly
refractive than the white. The ends of the
fibrillae are distinguishable in transverse
sections of the primitive bundles; and their
lateral margins are perfectly straight.

Different views have been taken of the
structure of the fibrillae, and, in fact, of the
general structure of muscle. Thus the ulti-
mate fibrillae have been described as monili-
form or beaded (PL 22. fig. 36 c) ; this ap-
pearance, however, arises from an optical
illusion, connected either with imperfection
in the object-glasses used, viewing the
object in too much liquid, or the use of too
low an object-glass, and too high an eye-,
piece.

MUSCLE.

[ 525 ]

MUSCLE.

Fig. 502.

A, a primitive bundle,
magnified 350 diame-

It often happens, especially when muscle
has been kept in spirit, that it separates trans-
versely into a number of flat disks (fig.^502) ;
hence it has been viewed as consisting of
these disks. Again, as
under certain conditions
it separates longitudi-
nally into fibrillae and
transversely into disks,
it has been supposed to
consist of primitive par-
ticles or * sarcous ele-
ments' united end to
end as well as laterally.
We admit the existence
of the primitive fibrillse
as original components
of muscle, though there
can be little doubt that
the fibrillse are not ho-
mogeneous, and of uni-
form constitution either
chemical or physical.
On carefully examining
them at different foci,
it is seen that those por-
tions of isolated fibrils

which appear dark when ters, partly separated

the margins of the fibrils {J^ ^^ mo?e

are best in focus, are magnified, end view.

more highly refractive
than the intermediate portions, as shown
by the greater luminosity they acquire on
altering the focus of the object-glass; and
that this focal effect does not arise from a
lenticular form of the parts is evident from
the straight condition of the margins of the
fibrils. Hence these more highly refractive
parts probably constitute the proper mus-
cular substance, connected in the direction
of their length by a different kind of sub-
stance, which becomes brittle under the
action of spirit, whilst the former does not ;
for the line of separation into the disks
occurs through the less highly refractive
portions. And that these compound fibrils
naturally exist, is shown by their being dis-
tinguishable in a primitive bundle without
the use of reagents, or even of mechanical
means.

It has always been supposed that the ulti-
mate fibrils are composed of cells arranged
end to end ; and the appearance represented
in PI. 22. fig. 36 a, which is sometimes met
•with, might countenance this notion. But
whenever it is seen, there is imperfect defi-
nition, from the presence of too much liquid,
or some other cause; for we have never

observed it when the object was properly
arranged and examined.

On examining the tibrillse under a very
high power, each white band is seen to be
divided by a faint dark line, Krause's line or
membrane, which is regarded as a trans-
verse partition, the compartments being
occupied by the true muscular substance ;
and it is through this line, that the fibrils
separate into the disks (PI. 22. fig. 36 d) ; or,
often the same part appears bounded at each
end by a transverse dark line (fig. 36 b), or
both parts are traversed mesially by a trans-
verse dark line. In some instances we have
noticed a very delicate constriction, which
would account for these appearances; but
the explanation of this we have failed to
discover.

The dark portions of the various fibrilL-e
of the primitive bundles being opposite to
each other, gives rise to the coarser dark
strise seen under a low power. But it often
happens that by pressure or manipulation
this natural relation is destroyed, the direc-
tion of the striae is altered, and sometimes
those of one bundle are made to alternate
with those of the next. Hence arises an
appearance of transverse or spiral fibres
(PL 22. fig. 35) ; but none such really exist
in muscle.

Muscle consists chemically of a proteine
compound called syntonine, resembling
fibrine in many of its properties. By pressing
muscles a liquid is obtained, contaiuiDg some
peculiar organic substances.

The unstriated and the striated muscular
fibres have the same chemical composition.

In regard to the development of muscle,
it appears that muscular fibre proceeds from
cells which elongate, each becoming fusi-
form, and at the same time increasing enor-
mously in thickness; the nucleus also in-
creases, and the cell-contents become striated
to form the muscle.

The muscles are very vascular. The
smaller branches of the vessels mostly run
parallel to the primitive bundles in the
perimysium, and anastomose by transverse
or oblique branches.

The bundles of transversely striated mus-
cular fibres in many of the lower animals,
and in the heart of man, are found to branch
and form networks. This may be well
observed in the muscles of the tongue of
the frog.

Schafer points out that the dark bands of
the muscular fibrils of certain insects, as
Dytiscus marginalis, are traversed by nume-

MUSCLE.

[ 526 ]

MUSCLE.

rous very slender parallel longitudinal mus-
cle-rods (PI. 22. fig. 36 e). These extend at
either end into the adjacent white bands,
terminating in knotted ends; forming a row,
running transversely across each white
band.

When muscular fibres are examined by
polarized light, the sarcous elements are
seen to be anisotropous or doubly refractive,
while the intermediate substance is iso-
tropous.

They are also well supplied with nerves ;
these mostly (always, Beale) terminate in a
plexus of looped branches (fig. 603).

Fig. 603.

Termination of the branches of a nerve in a portion
of the omohyoideus muscle, treated with caustic soda :
a, meshes of the terminal plexus ; 6, loops ; c, muscular
fibres.

Magnified 350 diameters.

In the Insects and Reptiles the nerves
terminate in granular nucleated swellings,
spread over the muscular bundles; their
sheaths becoming continuous with the sar-
colemma, the nerve-fibres branching off in
various directions.

Muscle undergoes important changes in
disease. Wounds are filled up with connec-
tive or tendinous tissue. In atrophy and
fatty degeneration, the bundles become
smaller, softer, more readily broken up, the
transverse striae and fibrillae indistinct, or

apparently absent, and contain yellowish or
brown pigment-granules, with more or less
numerous globules of fat (PI. 38. fig. 14 a),
and sometimes a large number of nuclei or
small cells.

Muscular fibres with nerve-ends from Lacerfa viridii.
A. Been in profile : P P, the terminal nerve expansion
or plate ; SS, its support or base, consisting of a granu-
lar mass with nuclei. B. The same, seen in a perfectly
fresh muscular fibre.

The interfascicular connective tissue is also
sometimes increased in amount, and fatty
tissues developed in it; or the muscular sub-
stance is partially absorbed, and the sarco-
lemma contracting gives the bundles a
moniliform appearance (PI. 38. fig. 146).
In tetanus, the fibres become varicose and
often ruptured, and the striae closer.

The muscular tissue of the lower Verte-
brata and some of the Invertebrata agrees
essentially in structure with that of man ;
but the sarcolemma is often much thicker,
the fibrillse larger, and the nuclei contained
within the substance of the bundles, and
sometimes arranged in regular linear series.
The margins of the bundles are also some-
times uneven, and rounded at regular inter-
vals (PI. 22. fig. 35), giving the appearance
of their being surrounded by fibres.

In many of the lower members of the In-
vertebrata, although the substance of the
body is voluntarily contractile, no trace of
fibres or bundles can be detected.

The so-called muscle-corpuscles are placed
in the interior of the fibre in the muscles
of the heart ; and they are to be met with in
Amphibia, Fishes, and Birds in the same
position.

MUSHROOMS.

[ 527 ]

MYRIANGIUM.

To obtain the separate fibrillae of striated
muscle, the tissue should "be macerated for
about two hours in alcohol. This removes
fatty matter, and renders the fibrillae more
easily separable by dissection with mounted
needles. The fibrillae are very minute;
hence a very small portion of the tissue only
should be taken for examination. That of
fishes, the cod or the skate, or of reptiles,
the frog, is the best for the purpose. Or,
the bottom of a glass vessel is covered with
chlorate of potash, slightly moistened with
water, and four parts of nitric acid added.
The whole is shaken, and a portion of muscle
buried beneath the crystals with a glass rod.
In half an hour, the inuscle is removed and
placed in water, and strongly shaken, when
it separates into the fibrillae (Kiihne).

The unstriated muscular fibres are best
seen in muscle which has been treated with
dilute nitric or muriatic acid (1 part acid to
4 water). This renders them more opaque,
and often curiously tortuous or spiral(fig.498).

BIBL. Bowman, Todd's Cycl. art. Muscle,
and Phil.Tr. 1840-41 ; Lebert, Ann. So. Nat.
3 se*r. xiii. ; Krause, Arch. An. u. Phys. h. v.
646, 1868; Moxon, Qu. Mic. Jn. 1866, 235;
Doyere, Ann. Sci. Nat. s6r. 2. 1840 ; Kuhne,
Brucke, Arnold, and Strieker, Strieker's Hist.
vol. i. 1870; Quain's^tw. ; Brucke, Bau d.
Muskel, Wiener Denkschr. xv. 79; Heppner,
Schultze's Archiv.v. 1869; Schafer,PM Tr.
v. 163, 429, 1873 ; Beale, How $c. 1880 j
Nasse, Quergesfr Musk. 1882 ; Frej,Hist. 301.

MUSHROOMS. See AGABICUS.

MUSSEL. — The species of Mollusca
commonly known as mussels are of interest
to the microscopist, on account of their ali-
mentary canal containing Diatomaceae ; the
same applies also to other marine and fresh-
water Mollusca, as well as other animals
living upon these minute Algse.

If it be required to obtain the valves only,
the entire animal may be dissolved in hot
nitric acid, and the residue washed as usual
in preparing the Diatomaceee.

The gills of the common marine mussel,
Mytihis edulis, are well adapted for the
examination of the cilia and ciliary motion.

Mussels also frequently contain the nurses
and larvae ( Cercarue) of Distoma and other
Trematoda.

One of the Acarina, Hydrachnaconcharum,
is found in the pallia! cavity or beneath the
outer lamella of the branchial plates of the
Naiadeae ( Unio, &c.).

BIBL. Dickie, Ann. N. H. 1848, i. 322 ;
Vogt, Ann. Sc. Nat. 3 ser. xii.

MUSTARD.— The best mustard consists
of the ground seeds of Sinapis nigra (Cruci-
ferse) ; but those of S. alba are largely em-
ployed. The structure of these grains is very
different from those of the substances most
commonly employed for adulteration, — for
example, wheat-Hour, which is known by
its starch-granules. Inferior samples con-
tain variable quantities of the husk of the
seed, which may be detected by the micro-
scope. Mustard is generally coloured arti-
ficially, especially when adulterated with
white meals, by means of TUBMEBIC, the
peculiar colour-cells of which are readily
recognizable. See PI. 2. fig. 11 ; and Hassall,
Food and Adulteration, 123.

MYCE'LIUM.— The vegetative part of
the Fungi as distinguished from the fruit.
Many fungi in a barren state have been
described as genera, Himantia, Ozonium,
Xylostroma. Mushroom-spawn is simply
the mycelioid state of Agaricus campestris.
The mycelium sometimes penetrates deeply
into wood, rendering it of various colours,
as green by Peziza ceruginosa, red by Corti-
cium sanguineum, yellow by Hypoxylon
luteum.

BIBL. Berk. Outl 39 ; Crypt. Bot. 262.

MYCETOZO'A. See MIXOMYCETES.

MYCOIDEA.— A genus of doubtful affi-
nity, allied to Chroolepus', propagated by
zoospores, also by sexual union, like Pythium
and some other Saprolegnise. 1 sp. ; on the
leaves of Camellia, in India (Linn. Tr. 2nd s.
i. 301, figs.).

MYCOP'ORUM, Hot. — A genus of
Lichenaceous Lichens. 3 sp., rare (Leighton,
Lich. Flo. 437).

MYELOPLAX'ES. See BONE, p. 111.

MYLITTA, Fr.— A genus apparently of
Tuberacei (Ascomycetous Fungi).

Mylitta australis, the native bread of the
Australians, has not been found with perfect
fruit ; but the structure is apparently that
of Tuberacei. The other species are doubtful,
and perhaps mere root-tubercules.

BIBL. Cd. Ic. ; Berk. Ann. N. H. 1839, 326.

MYOBIA, Heyd. See ACABUS, p. 5.
> MYOCOP'TES, Clap.— A genus of Aca-
rina. M. musculimis, on the body of the
mouse (Olaparede, Zeit. iviss. Zool. 18 ;
Murray, EC. Ent. 325; Megnin, 156).

MYO'MATA and MYXO'MATA. See

TUMOBS.

MYRIAN'GIUM, Mont, and Berk.— A
genus of Myriangiacei (Lichens). M. Du-
riai on ash and elm, rare. (Leighton,
Lich. Fl. 37).

MYRIAPODA.

[ 528 ]

MY1IIONKMA.

MYRIAP'ODA.— A class of Artliropoda.

Char. Wings none ; one pair of antennae ;
legs numerous ; thorax not separated from
the abdomen.

These animals are commonly known as
centipedes, millipedes, or hundred-legs.

Body usually long, cylindrical or flattened,
and consisting of numerous rings, joints, or
somites. Head distinct, and the jointed
legs, with a single claw, arranged on each
side of the body throughout its length. A
few of them are broad, short, and flattened,

Fig. 504.

lulus terrestris. Magnified 4 diameters.

somewhat resembling wood-lice. Behind
the antennae are laterally placed the eyes,
which in some are absent; they usually
consist of a group of ocelli.

The structure of the trophi varies in the
different genera. The labrum is small, and
usually consolidated with the cephalic plate.
The mandibles (PL 35. figs. 25, 26 b) are
often large and powerful, somewhat resem-
bling those of the spiders, and, like them,
traversed by a canal, through which the
duct of a poison-gland passes. The maxillae
are smaller, softer, and furnished with two
palpi. The labium (PI. 35. fig. 26 a) is
often deeply cleft, its anterior and inner
margin elegantly toothed ; and to it are
attached the labial palpi (fig. 26 c). In
some the labial palpi and mandibles are
absent, the labium forming a kind of sheath
or suctorial rostrum.

The internal structure resembles that of
the larvae of insects.

The sexes are separate. The embryo, on
escaping from the ovum, has but few legs,
sometimes three pairs, at others none, the
number being augmented each time the
skin is cast ; the same applies to the ocelli.

The Myriapoda live in dark places, be-
neath the bark of trees, under dead leaves,
stones, &c.

They form very interesting objects when
properly prepared and mounted. The small
ones, when slightly compressed between
two glasses, dried in that position, subse-
quently macerated in oil of turpentine, and
mounted in balsam, become very transpa-
rent, and show the structure beautifully;
the nervous ganglia and cords are often very
distinctly seen in these specimens without
dissection. The abdomen of the longer

specimens should be slit up with fine scis-
sors, and the viscera removed — the integu-
ment being gently compressed, and dried as
above.

BIBL.' Newport, Linn. Tr. xix. ; id. Phil.
Tr. 1841 ; Gervais, Ann. d. Sc. Nat. 2 stSr.
vii. ; Leach, Linn. Tr. xi. ; Jones, TodcTs
Cycl. An. iii. ; Fabre, Ann. d. Sc. Nat.
1855, iii. ; Packard, Amer. Natural. i\. ;
Cope, Tr. Amer. Ent. Soc. 1870 ; Lubbock,
Linn. Tr. 1867; Nicholson, ZooL 310; Pas-
coe, Zool. 90 ; Latzel, Myr. 1880.

MYRIONE'MA, Grev.— A genus of My-
rioneinaceae (Fucoid Algae), consisting of
minute epiphytic plants, forming patches of
short, erect, simple, jointed filaments, spring-
ing from a thin expanded layer of decum-
bent cohering filaments. They are described
as bearing oblong " spores ; " but these are
probably sporanyes producing zoospores, and
it is probable that they are accompanied by
septate sporanges, as in Elachutea.

M. strangulans. Patches convex, con-
fluent j erect filaments clavate ; spores on
the decumbent filaments; forms brown dots
upon Ulva, or little rings round Entero-
morphae.

M. Leclancherii. Circular; erect fila-
ments cylindrical, spores on the decumbent
filaments j in patches 1-12 to 1-4" in dia-
meter ; on decaying fronds of Hhodymenia
and Viva.

M. punctiforme. Patches globose ; fila-
ments tapering to the base ; spores very
narrow, fixed near the bases of the erect
filaments ; on Ceramia and Chylocladia.

M. clavatum', obscure.

BIBL. Harvey, Mar. Alg. 51 ; Grev. So.
Crypt. Fl. pi. 300; Harv. Phyc. Br. pi. 41 A ;
Hook. Br. Fl. ii. pt. 1. 391.

MTRIONEMAOE2E.

[ 529 ]

MYXOMYCETES.

MYRIOXEMA'CE.E — A family of Fu-
coideae. Olive-coloured sea-weeds, with a
tuber-shaped or crustaceous spreading frond,
sometimes minute and parasitical. Ovoid
unilocular, and filamentous multilocular
sporanges attached to the superficial fila-
ments, and concealed among them.

Leathesia. Frond tuber-shaped.

Ralfsia. Frond crustaceous.

Eldchistea. Frond parasitical, consisting
of a tubercular base bearing pencilled erect
filaments.

Myrionema. Frond parasitical, forming
a flat base, bearing cushion tufts of decum-
bent filaments.

MYRIOTHE'LA, Sars.— A genus of
Hydroid Zoophytes.

Char. Polypes solitary, cylindrical, ter-
minating in a conical proboscis, springing
from an adherent chitinous base; tentacles
small, capitate, covering the greater portion
of the body ; gonophores clustering round
the base of the polypes, and containing
fixed sporosacs. M. Phrygia, on stones.

BIBL. Sars, Zool. Reise in Lofoten; Gosse,
Mar. Zool. 19 ; Hincks, Hyd. Zooph. 75.

MYRIOTRICH'IA, Harv.— A genus of
Ectocarpaceaa (Fucoid Algae), consisting of
minute epiphytic plants, forming tufts of
capillary filaments on larger Algae. Fila-
ments simple jointed tubes, set all over with
minute, simple, spore-like ramules, which
again are clothed with very slender, long,
jointed filaments. Fructification composed
of oval unilocular sporanges on the sides of
the main axis, producing zoospores ; pro-
bably also multilocular sporanges exist.

M. claviformis. Main filament with quad-
rifarious ramules, increasing in length up-
wards; fronds 1-2" long, forming tufts on
Chorda lomenlaria.

M.JUiformis. Main filaments very long,
often flexuous, set at irregular intervals
with oblong clusters of minute papilliform
ramules; 1" or more long; on Chorda lo-
mentaria and Asperococcus echinatus.

BIBL. Harv. Phyc. Br.; Mar. Alg. 63;
Hook. Jn. Sot. i. 300.

MYROTHE'CIUM, Tode.— A genus of
Stilbacei (Hyphomycetous Fungi).

M. roridum, Tode, occurs on decayed
plants, fungi, &c. It has no peridium, but
consists of minute subcylindrical spores
seated on a thin base, the whole forming a
subgelatinous mass, which is exactly analo-
gous to the fructifying mass of Phalloidei.

BIBL. Berk. Br. Fl. ii. pt. 2. 323 ; Fries,
Sum. Veg. 448 ; Cooke, Handb. 559.

MYXASTRUM, Haeckel.— A genus of
Monera.

Char. A simple shapeless protoplasm
body without vacuoles, which protrudes
simple or ramifying and anastomosing pro-
cesses. Reproduction by radial fission. The
encapsuled resting body divides into a great
number of germs, whose longitudinal axis
is radially directed towards the centre of
the globular cyst. Each separate germ sur-
rounds itself with a siliceous covering. The
germs issuing from these spore-coverings
at once assume the form of the full-grown
organism.

M. radians. Lanzerote, Canaries.

BIBL. Haeckel, Monog. of Monera (Qu.
Mic. Jn. ix. n. s. p. 342).

MYXODIC'TYUM, Haeckel.— A genus
of Monera. Simple protoplasm bodies with-
out vacuoles ; pseudopodia ramifying, ana-
stomosing, and forming a net. Reproduc-
tion probably by division, each individual
producing new colonies. M. sociale. Bay
of Algesiras.

BIBL. Haeckel, Monera ( Qu. Mic. Jn. ix.
n. s. 339).

M YXOG AS'TRES = MYXOMYCETES.

M YXOMYCE'TES.— A family of minute
Fungi, of curious and interesting structure,
characterized by their development from a
mucilaginous filamentous matrix, out of
which arise sac-like dehiscent sporangia or
peridia, emitting a very remarkable, often
reticulated, filamentous structure, bearing
the spores.

The Myxomycetes grow upon bark of
trees, decayed wood, or on leaves (especially
under certain atmospheric conditions), or on
the ground ; and their evanescent mycelium
consists of diffluent mucilaginous proto-
plasmic filaments of varied form and colour.
In proportion as these acquire consistence,
there is formed a crust common to the
whole mass, divided within into chambers,
or a number of individuals appear separate
from it and associated on a common thal-
lus. In the first case a single peridium is
formed, which may be regarded as a com-
mon peridium if we consider the inner cells
as partial peridia soldered together, while
in the second case each individual has its
own peridium. This peridium, sessile or
stalked, is composed of one or more mem-
branous, papery, or crustaceous coats; in
some cases where there are two coats, the
outer is crustaceous and persistent, or it is
extremely thin and membranous, and breaks
up into deciduous scales. In the outer wall

2M

MYXOMYCETES.

[ 530 ]

MYXOMYCETES.

of some peridia, calcareous crystalloids are
found. The mode of deliiscence varies.
Sometimes an irregular opening is formed
at the summit, as in Physarum ; sometimes
the peridium opens like a little box, as in
Craterium (fig. 145, p. 213) ; sometimes the
upper half falls off, leaving a cup-shaped
base, as in Arcyria ; or the membrane may
be very delicate, and break up entirely into
little scales, which fall off and leave the
capillitium with its spores naked, as in Ste-
monitis. The capillitium or sporiferous
structure is formed of filaments, simple or
branched, free and loose, or anastomosing
so as to form a network (fig. 147, p. 214) ;
in Trichia these have spiral markings, and
resemble the elaters of Hepaticse (PL 40.
fig. 39). The filaments are often elastic,
and when the peridium bursts they rise
from the bottom of it, forming a coloured,
erect or drooping plume (Arcyria). In
many species there is a stalk, columella or
stylidium, in the centre of the capillitium.
The spores appear to be produced upon
these filaments by growing out from them
in the manner of basidiospores. They are
formed in vast numbers, and lie, when com-
plete, on the branches and in the interstices
of the capillitium.

Ju germination, each spore liberates its
entire protoplasm, which exhibits amoeboid
movements, and protrudes pseudopodia,
which anastomose as in Gromia. In some
instances, these amoeboid bodies acquire
cilia, resembling Monads. They then con-
jugate, finally forming a sporangium, in
which the capillitium with its very nume-
rous spores are produced. Some authors
regard these organisms as animal, but this
opinion seems to rest upon partial views.

Synopsis of British Genera.

* TBICHIACEI. Primary mucilage con-
joining several distinct peridia. Filaments
of the capillitium free, entwined, elastic, or
almost absent.

Licea. Peridium subpersistent, mem-
branous, bursting irregularly. Spores in
heaps, with scarcely any filaments.

Perichcena. Peridium persistent, mem-
branous, bursting by a circumscissile slit.
Filaments few, free.

Trichia. Peridium simple, persistent,
bursting irregularly at the summit. Fila-
ments densely interwoven, elastic.

Arcyria. Peridium simple, membranous,
splitting all round at the base, the upper

part very fugacious. Filaments densely in-
terwoven, elastic.

* STEMONITEI. Primary mucilage con-
necting several distinct peridia. Filaments
conjoined into a network, adnate or innate.

Cribraria. Peridium simple, membra-
nous, the upper part falling off. Filaments
adherent in the interior, at length expand-
ing into a free network above.

Dictydium. Peridium simple, subglo-
bose ; very delicately membranous, bur>lin^
indeterminately, leaving the filaments (in-
nate) forming " a cage-like latticed capilli-
tium.

Stemonitis. Peridium simple, globose or
cylindrical, delicately membranous, finally
evanescent. Filaments forming a determi-
nate capillitium, attached to a bristle-like
central columella, and forming a network
around it.

Diacheea. Peridium simple, ovate-oblong,
membranous, detached in fragments, leaving
a radiately reticulate capillitium, with a
floccose grumous pulverulent axis.

Enertlienema. Peridium simple, globose,
membranous, at length evanescent, laying
bare a conical columella with a cup at
the summit, bearing beneath ascending en-
twined filaments.

'* PHYSABEI. Primary mucilage spread-
ing widely, passing into many peridia. Fila-
ments adnate, straight, vague. Spores black.

Craterium. Peridium simple, varied,
papery, persistent, closed by a lid, which
finally falls off. Capillitium somewhat
chambered, formed of crowded filaments,
at length erect.

Physarum. Peridium simple, variable,
naked, membranous, bursting irregularly.
Capillitium floccose; filaments at first joined
into a net or forked.

Didymium. Peridium double ; the outer
bark-like, breaking up into little furfura-
ceous scales or mealy down, the inner mem-
branous, bursting irregularly ; filaments
vague, adnate to the peridium.

Diderma. Peridium double ; outer crust-
like, distinct, brittle, dehiscent, the inner
very delicately membranous, evanescent ;
filaments vague, adnate to the base.

**** ^ETHALINEI. Primary mucilage
producing one peridium.

Spumaria. Peridium indeterminate,
crustaceous, divided into cells by regular
ascending folds, and finally falling away.
No internal filaments.

_ jEthalium. Peridium indeterminate, fra-
gile, falling away, covered with a floccose

MYXORMIA.

[ 531 ]

NAIDINA.

bark externally, cellular internally by means
of filaments conjoined into membranous
layers.

Reticularia. Peridium indeterminate,
simple, naked, fugacious, bursting irregu-
larly, laying bare "branched, reticulated ad-
nate filaments.

Lycogala. Peridium determinate, com-
posed of a double membrane, membranous,
somewhat warty, persistent, bursting at the
summit. Filaments adnate on all sides of
the peridium.

BIBL. Schmitz, Linncea, xvi. 188; De
Bary, Die Mycetozoa, 1864; Hofmeister,
Phys. Bot. ii. 295 ; Cienkowsky, Jahr. wiss.
Bot. iii. 325, 400 ; Kent, Inf. 470 ; Sachs,
JRtf. 265; Cooke, Myxomyc.'l877.

MYXOR'MIA, Berk, and Br.— A genus
of Coniomycetes, containing one species, M.
atrovindis, forming minute cup-like bodies,
on dead leaves of grass. It is allied to
Exciptda, but differs in its concatenate spores
being connected by a slender thread, which
frequently breaks off with them; spores
very gelatinous.

BIBL. Berk, and Br., Ann. N. H. 2 ser.
v. 457 ; Cooke, Handb. 459.

MYXOT'RICHUM, Kze.— A genus of
Dernatiei (Hyphomycetous Fungi), growing
on rotten wood, paper, &c. Three British
species : M. casium, FT. ; M. chartarum,
Kze. ; and M. deflcxum, Berk. They form
little tufts or downy balls, sending off
radiating branched filaments. The spores
are described as occurring collected in
masses about the base of the threads.

BIBL. Berk. Br. Fl. ii. pt. 2. 335; Ann.
N. H. \. 260, pi. 8. fig. 9 ; Fries, Sum. Vey.
502 ; Syst. Myc. iii. 348 ; Church, Ann.
N. H. 1862.

MY'ZUS,Passerini.— A genus of Aphidae.
Four species; on the cherry-tree, peach
and nectarine, red-currant and gooseberry.
(Buckton, Aphides, i. 173.)

N.

NACCA'RIA, End!.— A genus of Crypto-
nemiaceae (Florideous Algee), containing one
rare British species, N. Wiyyhii (PI. 4.
fig. 18), usually thrown up from deep water.
Its rose-coloured frond is 6 to 12" high, and
consists of a branched filiform expansion,
the central axis being about as thick as a
crow-quill, the branchlets quadrifariously
alternate and clothed with ramules about
1-12" long. The cells of the main axis and
branches of the frond are large and empty
in the centre, small and closely packed at

the circumference ; the ramules are com-
posed of jointed dichotomous filaments
having a whorled arrangement, surrounded
by gelatinous matter. The spores are borne
on branches of the filaments of the ra-
mules, the fertile ramules being swollen in
the middle.

BIBL. Harvey, Mar. Alg. 152, pi. 20 D ;
Phyc. Br. pi. 38 ; Greville, Aly. Br. pi. 16.

NAIDI'NA. — A family of Setigera (An-
nulata).

Char. Worm-like, annulate or segmented,
without suckers or soft leg-like appendages ;
segments furnished with partially retractile
bristles or setae, excepting the first three or
four ; head distinct from the body.

Freshwater animals, living among aquatic
plants, or burrowing iu mud. Sexes distinct ;
propagation by ova and spontaneous trans-
verse division. The bristles are moved by
muscles, and answer the purpose of legs;
they are situated on the upper or under
surface of the body, mostly in rows.

The Naidina are remarkable for the sin-
gular process of non- sexual multiplication
which they present before attaining sexual
maturity. A bud is thrown out between
two rings near the middle of the body, and
is developed into a fresh individual ; more-
over the parent body separates at this point,
and becomes two individuals ; and prior to
the detachment of the bud, others are
formed from the same segment.

NaiSj Mull. Four anterior segments
without upper bristles.

N. Scotica. Cylindrical, ends obtuse, the
anterior smooth and cylindrical, the portion
behind it with a double row of thin tufts of
prickles, shorter than the diameter of the
body; mouth and anus terminal; no pro-
boscis ; length 1".

N. serpentina. Cylindrical ; head snake-
like, with a produced lower lip ; eyes two ;
upper bristles subulate, lower forked or
hooked; length about 1£". The lower
bristles with a globular swelling below the
middle ; segments 80-90 ; head with 4 dark
transverse bands.

N. proboscidea. Cylindrical, flattened in
front; first four segments divided by a
stricture from the body, the first or Head
being prolonged into a filiform proboscis;
two eyes; upper bristles simple, lower
forked ; length 1-2"; on the roots of aquatic
plants,

Chcetogaster, Baer. All the segments
without upper bristles.

C. vermicularis. Truncate in front: no

NAILS.

[ 532 ]

NAILS.

eyes; mouth terminal; setae bifid; length
1"; among Lemna, in ditches, and in the
respiratory chamber of the Lymnaeidae.

See TUBIFEX.

BIBL. Schmidt, Midler's Archiv, 1846,
406; Duges, Ann. Sc. Nat. 2 ser. xv. 319 ;
Johnston, Cat. non-par asit. Worms ; Doyere,
Mem. Linn. Soc. Normandy, x. ; Claparede,
Rech. 1861.

NAILS. — These organs, which consist of

modified epidermic formations, are imbedded
posteriorly and laterally in depressions, or
are covered at these parts by a fold of the
skin. The posterior depression (fig. 505 d )
is much deeper than the lateral depressions
(fig. 506 c\

The nail itself consists of the root (fig.
505 0, the body (&), and the free end (wt).
The root extends over that part of the
matrix furnished with the ridges, and is

Fig. 505.

Longitudinal section through the middle of the nail and its matrix, o, matrix and cutis of the back and point
of the finger; b, rete mucosum of the point of the finger; c, that of the nail ; d, that of the bottom of the root-
fold ; e, the same of the back of the finger ; f, epidermis of the point of the finger ; g, its origin beneath the margin
of the nail ; A, epidermia of the back of the flnger ; t, its termination at the upper surface of the root of the nail ;
k, body, I, root, m, free end of the proper nail.

Magnified 8 diameters.

either entirely lodged in the posterior de-
pression of the cutis, or the crescentic por-
tion of it is exposed. The body of the nail
is uncovered except at the sides, which are
overlapped by the lateral folds of the skin.

The portion of the cutis (fig. 506 a) to
which the under surface of the nail, except
that of the anterior free portion, is attached
— the matrix or bed — is covered with ridges
(fig. 506 «) extending from the posterior
part or root of the nail to the convex mar-
gin of the white crescentic portion called
the lunule, where they become larger and
higher, forming plates which run to the end
of the matrix. The margins of the ridges
and plates are covered with short papillae.
The anterior portion of the matrix of the
nail is very vascular.

The under surface of the root and body
of the nail is covered with depressions and
ridges to adapt itself to those of the matrix.

Two layers are distinguishable in the
nails — an under soft layer (figs. 505 d, 506 c,
5075), corresponding to and directly con-
tinuous with the rete mucosum of the skin,
and the upper horny layer forming the true
nail (figs. 506/, 505 k, 507 C). The lower
surface of the latter is furnished with small

ridges (fig. 507 c), which occupy correspond-
ing furrows in the mucous layer.

In minute structure the soft layer resem-
bles that of the cutaneous rete, except in
the deeper layer of cells being elongated
and arranged perpendicularly (fig. 507 6).

The horny portion, or proper nail, con-
sists of epidermic cells, flattened and aggre-
gated into plates or laminae (fig. 507 C).
In the natural state, these cells are undistin-
guishable, except at the root and the under
surface, where the nail is in contact with
the mucous layer — the remainder merely
exhibiting shorter or longer dark lines, re-
presenting the flattened nuclei, or indicating
the existence of the laminae. But if a
section of nail be treated with solution of
caustic potash or soda, the nucleated cells
swell up, and resume their proper form and
appearance.

The blood-vessels of the bed of the nail
form a coarse plexus in the corium of the
matrix, from which loops are given off to
the papillae ; and the proper bed of the nail
has a much finer plexus and loops ascending
to the ridges.

Numerous medullated nerve-fibres lie in
the subcutaneous tissue of the nail-bed, and

NAILS.

[ 533 ]

NASSULA,

Transverse section of the nail and its matrix, a, matrix with its ridges (black) ; 6, cutis of the lateral fold • e,
rete mucosum of the same; d, rete mucosum of the nail with its ridges (white) ; e, epidermic layer of cutaneous
fold; f, proper substance of the nail, with short teeth on its under burface.

Magnified 8 diameters.

lose their medullary sheath at the level of
the corium, and then run vertically to the
surface.

Fig. 607.

Transverse section of the body of the nail. A, cutis
of the matrix.- B, rete mucosum of the nail. C, epi-
dermis of the same, or proper nail, a, plates of the
matrix; 6, plates of the rete mucosum of the nail; c,
ridges of the proper substance of the nail ; d, deeper
perpendicular cells of the rete mucosum of the nail ;
e, upper flattened cells of the same ; f, nuclei of the
cells of the proper nail.

Magnified 250 diameters.

The cutaneous epidermis (fig. 506 e) ex-
tends for a certain distance into the lateral
and posterior depressions of the skin, covers
the anterior portion of the root, the poste-
rior part of the "body, and the lateral mar-
gins of the nails, terminating in a fine layer
which, however, is nowhere directly con-
tinuous with the substance of the nail.

Laminse of a nail after boiling with solution of caustic
soda or potash. A, side view. B, surface view, a, cell-
membranes ; b, nuclei seen from above ; c, the same in
side view.

Magnified 350 diameters.

BIBL. Kolliker, Mik. An. ii. and the JBibl.
therein ; Biesiadecki, Strickw's Hist.

NAIS, Mull. See NAIDINA.

NANNOPUS, Brady.— A genus of Cope-
podous Entornostraca. (Brady, Cop. ii.)

N AB/COTINE. See ALKALOIDS, p. 31 .

NAS'SULA, Ehr.— A genus of Holo-
trichous Infusoria, of the family Trachelma.

Char. Body covered with cilia arranged
in longitudinal rows; mouth surrounded by
a cone of rod-like teeth ; no proboscis nor
ear-like processes.

The gastric sacculi of these animals fre-
quently contain a coloured liquid, derived
from the solution of partly digested Oscilla-
torice.

N. elegans (PL 31. fig. 45; b, teeth).
Length 1-144 to 1-120".

N. aurea (PL 31. fig. 46). Length 1-120".

NAUPLIUS.

[ 534 ]

NECTRIA.

It is questionable how far this genus is
different from Chilodon.

BIBL. Ehr. In/us. 338; Stein, Inf. 248;
Cohn, Qu. M. Jn. 1859 ; Clap, et Lachrn.
Etudes ; Kent, Inf. 494.

NAUTLIUS. See CRUSTACEA, p. 216.

NAVICELL^E. See GHEGAMNA, p.36o.

NAVIC'ULA, Bory.— A genus of Diato-
maceae.

Char. Frustules single, free; valves ob-
long, lanceolate or elliptical, sometimes with
the ends narrowed and produced, rarely
constricted in the middle, furnished with a
longitudinal line or keel, and a nodule in
the middle and at each end; surface of
valves covered with dots arranged in trans-
verse or slightly radiating rows, producing
an appearance of lines, although both dots
and lines are often invisible by ordinary
illumination.

Valves usually symmetrical, and the keel
median ; but in two species the keel is
sigmoid and the valves inequilateral. Some-
times the keel is double. There is mostly
a little space between the rows of dots
(PI. 15. fig. 8), so that these readily exhibit
transverse lines or striae by unilateral oblique
light; but sometimes they are pretty uni-
formly distributed, as in many of the species
belonging to the first section of Pleuro-
siffma.

Species or forms very numerous ; Kiitzing
describes 170, some of them, however, be-
longing to Pinnularia, Pleurosigma, and
other genera. Rabenhorst notices 237 spe-
cies. Many may have been derived from
a frustule of a Schizonema or Colktonema
which had escaped from its gelatinous
envelope I

The formation of sporangial frustules has
been noticed by us in Navicula amphirhyn-
chus, and they are contained in a siliceous
sporangial sheath or case. The process is
sufficiently illustrated by the figures (PI. 50.
figs. 19-24) : fig. 19, side view of the parent
frustule ; fig. 20, front view of conjugating
frustules, with young sporangial sheath;
fig. 21, empty mature sheath ; fig. 22,
crushed empty sheath and parent frustules
in situ ; fig. 23, sheath, one parent frustule
and sporangial frustule in front view ; fig.
24, sporangial frustule in side view.

N. cuspidata (PL 15. fig. 6, side view;
fig. 7, front view ; «, hoop). Valves lan-
ceolate, somewhat rhomboid, acuminate;
freshwater; length 1-350 to 1-200". ^ Valves
slightly iridescent, no striae by ord. ilium.

N. didyma (PI. 15. fig. 9). Valves ellip-

tic oblong, slightly constricted in the middle;
marine; length 1-000 to 1-300". Ends
sometimes broadly rounded, and the con-
striction very deep.

N. rhomboides. Valves rhomboid-lanceo-
late; colourless and not striated by ordin.
ilium.; freshwater; length 1-350". Striae
85 in 1-1000" (8m.).

N. amphirhynchm (PI. 50. fig. 19, side view ;
fig. 22, front view of conjugating frustules).
Valves linear, or nearly so, suddenly con-
tracted near the produced and obtuse ends j
freshwater ; length 1-500 to 1-250".

N. affinis. Valves elliptical, contracted
and linear towards the rounded ends; fresh-
water.

BIBL. Smith, Br. Diat. i. 46 ; Kiitz, Ba-
cill. 91, and Sp. Alg. 69 ; Grev., n. sp., Mic.
Tr. 1866, 84 & 126; O'Meara, pec. forms,
Qu. Mic. Jn. 1872, xii. 283 ; Rabenh. Ala. i.
169.

NEBA'LIA, Leach.— A genus of Phyllo-
podous Entomostraca.

Char. Antennae two pairs, large and rami-
f orm ; eyes two, stalked ; legs twelve pairs,
eight branchial and four natatory ; carapace
large, enclosing head, thorax, and part of
abdomen.

N. bipes (PI. 19. fig. 28). Marine; body
yellowish ; length 3-8".

BIBL. Baird, Br. Entom. 36 ; Glaus, Sieb.
Sf Koll. Zeits. 1872,- 323 ; An. N. H. 1879,
iv. 418.

NECKE'RA, Hedwig.— A genus of Hyp-
noid Mosses.

Elegant little perennial plants, growing
on trunks of trees and shady rocks, having
stems pinnately branched, bearing compla-
nate leaves arranged in eight rows (fig. 484).

N. crispa, Dill., found in mountainous
districts, is a large moss, with stems 4 or 6"
long or more, growing horizontally from a
creeping rhizome.

NECTRIA, Fries.— A genus of Sphaa-
riacei (Ascomycetous Fungi), distinguished
from true Sphcsrice by the free, membranous,
flaccid, brightly coloured perithecium, the
pale papilla, and the gelatinous pale nucleus
expelled in the form of a drop or of white
flocks ; the asci contain eight pellucid
spores. The imperfect forms of these plants
are described as distinct genera. Thus
Tubercularia vulgaris, common on bark of
dying or dead trunks, and on dead twigs of
birch especially, ripens into N. cinnabarina ;
this we have observed ; and it is probable
that other Coniomycetous forms will require
to be reduced in like manner. Nectria

NEMALEON.

[ 535

NEPHB03ELMIS.

includes the following Sphcerice of the
British Flora — cinnabar ina, coccinea, ochra-
cea, aurantia, rosella, citrina, Peziza, san-
guinea, epispliceria, &c. ; and several new
species are described by Messrs. Berkeley
and Broome.

BIBL. Fries, Sum. Veg. 387 ; Berk. &
Broome, Ann. N. H. 2 ser. xiii. 467 ; Cooke's
Handb. 780.

NEMA'LEON, Targioni. — A genus of
Cryptoneniiaceae (Florideous Algae), con-
taining two British species, one, N. mukifi-
dum, not uncommon on shells and stones
near low-water mark. Its frond consists of
a somewhat cartilaginous, simple or once or
twice dichotomous cord, 3 to 6" high and
1 to 2" in diameter, of a dull purple colour.
The cord consists of a dense axis formed of
interlaced longitudinal filaments, clothed
with horizontal, dichotomously-branched
filaments, moniliform and coloured towards
the circumference of the cord. The fruit
consists of :— -favellidia, consisting of glo-
bular masses of spores attached singly to
the filaments of the periphery, with a tri-
chogyne (PI. 4. fig. 12 c) ; and collections
of antheridia, consisting of minute hyaline
cells seated on the peripheral filaments, but
discharging spermatozoids (PI. 4. fig. 12 b).

BIBL. Harv. Mar. Alg. 153, pi. 21 B,
Phyc. Br. pi. 36 : Derbes and Solier, Ann.
Sci. Nat. 3 ser. 'xiv. 274, pi. 35 j Thuret,
ibid. 4 ser. iii. 21.

NEMAS'PORA, Fries.— A supposed ge-
nus of Melanconiei (Coniomycetous Fungi),
the species of which present two forms, one
bearing minute conidia (Nemaspora), the
other spores (Zi&erfeZfo, Desmaz.), and which
probably also will be found to exhibit an
asciferous form. N. crocea, Pers., is common |
on beech trees, N. Rosce on roses aud lilacs.
They are at first minute gelatinous masses
of conidia, coherent into a nucleus under
the epidermis, devoid of a perithecium ; the

rres finally exude as a gelatinous tendril ;
spores are curved and of an orange-
colour. Nemaspora consists really of sper-
mogonous fruits, and Libertella of stylospo-
rous fruits of Asconiycetous genera.

BIBL. Berk. Br. Fl. ii. pt. 2. 355 ; Fries,
Sum. Veg. 413 ; Desmaz. Ann. Sc. Nat. 1
ser. xix. 269.

NEMATHE'CIA.— Wart-like collections
of vertical filaments found on the surface of
the fronds of the Cryptonemiaceae (FLO-
RIDE^).

NEOTTIOS'PORA, Desmaz.— Agenus of
Sphaeronemei(Stylosporous Fungi), remark- I

able from the fusiform spores being fur-
nished with three or four terminal threads.
N. caricum grows upon deid leaves of
sedges, bursting from beneath the epidermis
by a circular black orifice, from which an
orange-coloured (sometimes olive-coloured)
gelatinous mass of spores escapes in the
form of a cirrhus. Diameter of conceptacles
about 1-80".

BIBL. Desmazieres, Ann. Sc. Nat. 2 ser.
xix. 346; Berk. & Broome, Ann. N. H.
2 ser. xiii. 379.

NE'PA, Linn. — A genus of Hemipterous
Insects.

N. cinerea, the common water-scorpion,
is of a dirty brown colour, the body broad
and flat, with two long terminal respiratory
tubes ; anterior pair of legs stout and greatly
elbowed, posterior formed for crawling and
not swimming.

PI. 33. fig. 26 represents the trophi. The
labium (i) is three-jointed, with two small
lobes between the second and third joints ;
the four setae (mandibles and maxillae) are
furnished with teeth, directed towards the
free end (and not as shown in the figure) ;
the lingua or tongue (*) is trifid at the
apex.

The lateral tracheae are dilated opposite
the thorax to form two internal respiratory
sacs. The eggs are oval, and with seven
reflexed filaments at one end.

BIBL. Westwood, Intr. ; Dufour, Hcmip-
teres.

NEPEN'THES, L.— A genus of Nepen-
thaceas (Dicotyledonous Plants), in which
the spiral vessels have four parallel fibres
(see SPIRAL STRUCTURES).

NEPHROCY'TIUM, Nag.— A genus of
Paknellaceae ; consisting of 4-16 minute
renifbrm green cells, enclosed in an ample
envelope. 2 species ; in ditches and boggy
pools. (Rab. Fl. Alg. 52; JSTag. Einzell.
Alg. 79.)

NEPHRO'DIUM, Rich.— A genus of
Aspidieae (Polypodiaceous Ferns, fig. 224.
p. 320). A very large number of species,
cosmopolitan. "Brit. sp. : N. Ftiix-mas,
Thelypteris, Oreopteris (montnnum), rigi-
dum, cristatum, spimdosum (dilatatum), and
eemula.

NEPHRO'LEPIS, Schott— A genus of
Aspidieae (Polypodiaceous Ferns). 7 spe-
cies, tropical. (Hooker, Syn. 300.)

NEPHRO'MIUM, Nyl.— A genus of
Lichenaceous Lichens. Three species; rare.
(Leighton, B. Lick. Fl. 99.)
NEPHROSEL'MIS, Stein.— A genus of

NERIUM.

[ 536 ]

NERVES.

Flagellate Infusoria. Free, solitary ; fla-
gella two, arising from the middle of the
ventral side. N. olivacea, reniform ; length
1-1000" ; freshwater. (Kent, Inf. 405.)

NERIUM. See STOMATA, and LIBER
(p. 461).

NERVES and NERVOUS CENTRES.
— The nervous system is usually regarded
as consisting of two parts — the nerves, which
are divided into the cerebro-spinal and the
sympathetic; and the nervous centres, re-
presented by the brain and spinal cord,
with which must also be placed the ganglia.
These parts are composed essentially either
of nerve-tubes, nerve-cells, or of both these
elements.

The nerve-fibres may be arranged in two
groups, the medullated and the non-medul-
lated.

The medullated nerve-tubes are most nu-
merous in the white portion of the nervous
centres and in the nerves. They are slender,
soft, cylindrical filaments, varying in diam-
eter from 1-20,000 to 1-HOO". When
quite recent, they are transparent and appa-
rently homogeneous (fig. 509, 1), but they
really consist of three distinct parts — an
enveloping membrane or sheath ; a tenacious
liquid, the white substance of Schwann ;
and a soft, elastic, and probably fibrous
axis, the axis-cylinder, or band of Remak.

The outer sheath or tubular membrane
of the nerve-tubes is a thin structureless
transparent membrane (fig. 510, 2, 3 a, 4 a\
containing nuclei. It is very visible and
thick in the nerves of the mesentery of the
frog, and in the electrical organs of the tor-
pedo. It is furnished with annular con-
strictions at regular intervals.

"Within the outer sheath is a hollow
cylinder or tube (figs. 509, 3b, 510, 3b,4b)—
the white substance of Schwann. It is
homogeneous and tenacious in perfectly fresh
nerves, but soon after death becomes coagu-
lated, sometimes externally only, giving a
double outline to the walls of the nerve-
tubes (fig. 510, 4) 511), or becoming granular
externally, and remaining liquid internally.
It is also easily altered by pressure, some-
times escaping in globules or masses of
various forms (myeline), from the ends or
the broken sides of the tubes, at others
accumulating at intervals in various parts
of the tubes, giving them an elegant vari-
cose appearance (fig. 511). It is frequently
called the medullary sheath, and those nerves
possessing it are medullated.

The third structure exists within the last,

in the form of a rounded or flattened, pale,
fibrous band, occupying the axis of the tube,
and called the axis-cylinder (figs. 509, 2 b,
So, 4 a, 5; 510, 1 b); this is the essential
nervous element.

Fig. 509.

Nerve-fibres. 1. From nerves of the dog and rabbit,
in the natural state : a, fine, b, moderate, c, large fibre.
2. From a frog, after the addition of serum : a, drop
forced out by pressure ; b, part of the axial fibre con-
tained in it. 3. From the human spinal marrow, treated
with serum : a, sheath ; b, white substance with a cloxible
outline ; c, axial fibre. 4. Fibre with double outline,
from the human fourth ventricle : a, axial fibre. 5. Two
isolated axial fibres, with a portion of the white sub-
stance adherent to the right-hand one.

Magnified 350 diameters.

These three structures of nerve are some-
what difficult of demonstration. The outer
sheath may sometimes be shown by pressing
the nerve-tube, which forces out the white
substance. Boiling the nerves in absolute
alcohol, with the subsequent addition of
caustic alkali, or in acetic acid, when crys-
tals of fat separate from the white substance
(fig. 510, 1), will answer the same purpose.
Strong nitric acid, and afterwards potash,
causes the white substance to exude; and
the axial fibre being dissolved, the yellow
sheath is left empty and very distinct. So-
lution of corrosive sublimate has also been

NEKVES.

[ 537 ]

NERVES.

recommended. The axial band is best seen
in nerves treated with strong acetic acid, or
cold absolute alcohol, ether, chromic acid,

Nerve-tubes. 1 . From a frog, after boiling with acetic
acid and alcohol : a, sheath ; 6, axial band ; c, crystals
of fat. 2. Isolated sheath of a frog's nerve boiled with
soda. 3. From the human fourth ventricle, after treat-
ment with soda : a, sheath ; b, white substance exuding
in drops : the axial band has been removed in the pre-
paration. 4. Human, treated with soda : a, sheath; 6,
white substance ; the axial band not visible.
Magnified 350 diameters.

. 511.

Human nerve-tubes, showing tubes of various sizes ;
some with a single, others with a double outline ; some
varicose, others with the white substance in a granular
state.

Magnified 350 diameters.

&c., and staining fluids. Osmic acid so-
lution hinders the coagulation of the medul-

lary substance, which is oily and very re-
fractive, and turns it black.

Chemically, the sheath and axial band
consist of a proteine compound, and the
white substance of a mixture of cerebrine
with lecythine.

In the non-medullated nerves the fibres
are of three kinds. The primitive nerve-
fibrils present the simplest form, and are
very fine and thread-like. They are only
visible with powers greater than 500 linear,
and may be traced to their junction with
ganglion-cells and thicker nerve-fibres. No
internal structure can be distinguished ; and
they become varicose here and there with
reagents, such as osniic acid, finally becom-
ing diffluent. They abound in the neigh-
bourhood of the termination of other nerves,
for instance, in the retina (see EYE).

The second kind of fibres have been called
naked axis-cylinders, and are thicker than
the primitive fibrils. They are transparent,
and more or less striated longitudinally,
being composed, like the axis-cylinders of
medullated nerves, of minute longitudinal
fibrils. When connected with nmltipolar
ganglion-cells, this fibrillation is often di-
stinct under the action of reagents. They
have only been traced for short distances j
and it is evident that they and the primitive
fibrils may become covered with a sheath
and merge into the medullated type. The
third kind consists of a thicker or thinner
bundle of primitive nerve-fibrils, according
to the kind of axis-cylinder present, united
together by a structureless, perfectly trans-
parent, extremely thin nucleated tissue —
the tubular sheath of the medullated fibres.

In the cerebro-spinal nerves, the nerve-
tubes are aggregated into bundles, and sur-
rounded by an envelope of connective tissue,
called the neurilemma, in which blood-
vessels ramify, thus corresponding with the
arrangement of the primitive fibrillse of
muscle. Sometimes, towards the termina-
tions of the nerves, the neurilemma appears
as a homogeneous membrane with elongated
nuclei.

Branching or division of all the nerve-
fibres, except the non-medullated primitive
kind, occurs occasionally in and near the
nervous centres and in the nerve-trunks, and
frequently in the periphery. The best
example of peripheral divison is in the
electric eel, where one medullated fibre
divides millions of times to supply the sub-
cutaneous fat-like organ. Division into
fibres may be seen in sections of the spinal

NERVES.

[ 638 ]

NERVES.

cord of the ox treated with carmine and
ammonia.

In the grey, sympathetic, or ganglionic
nerves, the fibres of which are sometimes
called gelatinous fihres, the nerves are paler
than those of most of the cerebro-spinal
nerves, and they are scattered through

Fig. 512.

From the human sympathetic. A. Portion of a grey
fibre treated with acetic acid: a, fine nerve-tubes; o,
nuclei of Remak's fibres. £• Three ganglion-globules,
one with a pale process.

Magnified 350 diameters.

numerous longitudinal non-medullated fibres
(Remak's fibres), containing elongated nuclei
(fig. 512).

N&'ve-cells, nerve-corpuscles, or ganglion-
globules are masses of fibrillar protoplasm,

granular and faintly coloured ; they have a
nucleus and nucleolus. They are most nu-
merous in the cineritious or dark portions of
the nervous centres, and in the ganglia ; but
they are met with in the trunks and termi-
nal expansion of nerves, as the retina, &c.
Some are furnished with a nucleated capsule
(tig. 513, 2 a) ; this is easily seen in the
cells of the ganglia, but with difficulty in
those of the central organs.

They are rounded, elongate, pyriform, or
angular (fig. 513). Some are simple, others
are furnished with one, two, or more simple
or branched processes ; hence they are
described respectively as uni-, bi-, or multi-
polar. Their contents are a soft, tenacious,
but fibrillar mass (fig. 513, 3), consisting of
a clear, homogeneous, proteine basis, and a
number of larger and smaller granules, as
well as a nucleus and nucleolus. In size
they are very variable, from 1-5000 to 1-500".
The granules are sometimes colourless, at
others yellow, brown, or black ; and occa-
sionally these are aggregated to form a
mass.

A number of fine fibres radiating from
the nucleus and nucleolus may be seen
traversing the cell-substance, which con-
tains granular, yellow, or reddish-brown
pigment. Chloride of gold renders the
nucleus very distinct. Beale has shown
that two processes are given off from the

Fig. 513.

"N"erve-cells and fibres from the auditory nerve. 1. Nerve-cell with the origin of a fibre, from the anastomosis
between the facial and auditory nerve in the meatus auditorius externus of the ox: a, cell-membrane ; b, contents ;

Magnified 350 diameters.

NERVES.

[ 639 ]

NERVES.

small end of the bell-shaped ganglion-cells
of the sympathetic in the frog, and that
whilst one pursues a straight course, the

Fig. 514.

Cells from the central grey substance of the human
spinal marrow. Some are connective-tissue cells.
Magnified 350 diameters.

other forms a series of coils around it, both
lying within a nucleated sheath continuous
with that of the ganglion-cell.

Origin of Nerve-fibres. — The ganglion-
cells, whether multipolar or unipolar, are in
continuity with nerve-fibres. Some gan-
glion-cells are merely nucleated dilatations
of the axis-cylinder ; and others, which are
also bipolar, are true ganglion-cells; for the
more or less globular cell-mass is continuous
with the axis-cylinder and with the granu-
lar matter of the medullary matter, but the
tubular sheath of the nerve stops short of
the cell.

Multipolar ganglion-cells are invariably
connected with one medullated nerve-fibre,
which passes off without branching or
diminishing in calibre. Its axis-cylinder is
continuous with the fibrillar structure of the
protoplasm of the ganglion-cell, and it be-
comes invested with the medullary sheath
soon after leaving the cell. The other pro-
cesses either communicate with adjacent
multipolar cells, or break up after repeated
branching into a great number of processes,
which,however, are clearly continuous with
the fibrillar protoplasm of the cell, but are
uncovered by any medullary sheath. Their
ultimate termination is doubtful ; but it is
inferred that many of them become continu-
ous with the axis-cylinders of nerves. So

Fig. 515.

Large cells from the grey cortical layer of the human cerebellum. Magnified 350 diameters.

fibrillar are the processes under reagents,
and so fibrous is the appearance of the gan-
glion cell-mass, deficient as it is of cell-wall,

that it is imagined that the fibrous structure
of the axis-cylinders is continuous with that
of each other through the cell-substance.

NERVES.

[ 540 ]

NERVES.

Doubtless many nerve -fibres originate from
very small cells imbedded in the grey sub-
stance, and which are usually destroyed by
the processes of preparation.

The ganglia (fig. 516) consist of nerve-
tubes either separate or united into bundles,
intermingled with nerve-cells, from which
some of the nerve-tubes arise. The tubes
and cells are imbedded in or supported by a
stroma of connective tissue, sometimes
homogeneous, at others more or less di-
stinctly fibrous, forming an apparent sheath
to the ganglia, and ending in numerous

Fig. 516.

septa, rarely but occasionally forming a di-
stinct envelope to the individual cells; some-
times it consists of elongated, triangular, or
spindle-shaped nucleated cells — in short,
corresponding to connective tissue in various
stages of development.

The finer nerve-fibres are often with diffi-
culty distinguished from fibres of connective
tissue; but the frequent occurrence of nuclei
will often serve to distinguish them.

The nerves are developed from the ele-
mentary embryonic cells, which at first
appear rounded or slightly elongated and

Fig. 617.

Pic 516. Sixth thoracic sympathetic ganglion of the left side of a rabbit, seen from behind, after treatment with
soda T. 2, trunk of sympathetic ; E. c, communicating branches, each bifurcating; Spl. splanchnic branch. S, gan-
glial branch, with large and small branches probably going to vessels; g, ganglion-globules and ganghal fibres.

*££ 517 1 ^nolfon-elobules from a spinal ganglion of a four-months human foetus: a, nucleus in the pale
process of the cell? 2. Nerve-tubes in development, from a two-months human foetus. 3. Cells from the cineri-
tious cerebral substance of the same foetus.

Fig. 518. 1. Two nerve-fibres from the ischiatic nerve of a four-months foetus. 2. Nerve-tubes from a newly-
born rabbit: a, sheath; 6, nucleus; c, white substance. 3. Nerve-fibre from the tail of a tadpole: a, b, c, as above;
at d the fibre has still the embryonic character.

somewhat flattened. In their further growth
they either retain their primitive shape (fig.
517), or send out persistent lateral pro-
cesses, so forming nerve-cells or ganglion-

globules ; or the processes of adjacent cells
unite into nucleated fibres, much resembling
those of the sympathetic system, in which
the white substance and axial fibre of the

NEUROGLIA.

[ 541 ]

NIDULARIACEI.

nerve-tubes are formed as secondary depo-
sits (fig. 518).

In atrophy and degeneration of the
nervous elements, the nerve-cells become
loaded with fat and pigment, and the walls
of the nerve-tubes thinner, brittle, and the
white substance more or less replaced by
granules of fat.

The nerve-fibres are very difficult of ex-
amination, and require a high power. They
may be hardened in chromic acid or Miiller's
liquid. Chloride of gold with the subsequent
addition of very dilute acetic acid, brings to
light the axial fibre ; while the medullary
sheath is darkened by osmic acid.

BIBL. Kolliker, Mik. An. 2 ; Todd, Cycl.
iii. ; Gerlach, Mik. Stud. ; Remak, Monatsb.
Acad. Berlin, 1853 ; Schultze, Struct, nerv.,
1868 ; Lister & Turner, Qu. Mic. Jn. I860,
29 ; Mayer, Strick. Hist. ; Meynert, ibid. ;
Deiters,* Gehirn u. Mark d. Memch., 1865 ;
€larke, Phil. Tr. 1868 ; Beale, Phil. Tr. 1860,
1862, 1863,1864, Croon. Lecture 1865, Qu.
Mic. Jn. n. s. vols. iv. & v., & How ; Cleland,
Qu. Mic. Jn. 1870, 126; Darwin, Qu. Mic.
Jn. 1874, 110; Schmidt, M. Mic. Jn. 1864,
200; Frey, Hist. 624; B3van, M. Mic. Jn.
xvi. 105. "

NEUROGLIA. — A granular connective
tissue, with fine elastic fibres and cells sur-
rounding the nerve-fibres in the brain and
spinal cord.

NEUROP'TERA.— An order of Insects,
containing the Dragonflies (LIBELLULID^E).

NEW-ZEALAND FLAX. See PHOR-
MTUM and TEXTILE SUBSTANCES.

NEWT. See TRITON.

NICOTH'OE, Aud. & Edw.— A genus of
Crustacea, of the order Siphonostoma, and
family Ergasilidse.

N. astaci (PI. 19. fig. 36, fern.) is found
upon the gills of the lobster.

The sides of the body are extended into
two remarkable lobes, containing the ovaries
(«) and the intestinal canal.

BIBL. Baird, Br. Ent. 300; VanBeneden,
Ann. Sc. Nat. 3 ser. xiii.

NIDULARIA'CEL— A small family of
Oasteromycetous Fungi, including the Ni-
dularini or bird's-nest-like Fungi, and the
Carpoboli, which contain only one concep-
tacle. They are curious and very interest-
ing Fungi, growing on the ground among
decaying sticks, dung, &c., bearing upon the
flocculent mycelium yellow or dull-coloured
fruits or receptacles (fig. 519). The ex-
ternal part of the receptacle consists of a
more or less globular or ovate peridium,

which bursts when mature, in the Carpoboli
by a lid or by more or less regular slits, in
the Nidulariui by an orifice which enlarges

Fig. 519.

Fig. 520.

Fig. 521.

Cyathus vemicosus.

Fig. 519. A ripe receptacle. Nat. siae.
Fig. 520. The same, opened vertically.

so that the mouth becomes turned out as a
spreading lip around a cup-shaped cavity
(fig. 519). The Carpo-
boli, containing only
one conceptacle, project
this with elasticity
when ripe. The Nidu-
larini contain many
conceptacles lying like
eggs in a nest (figs.
519, 520), in Cyathus
and Crucibulum (fig.
521) attached by a funi-
culus. The structure
of the conceptacles is
alike in all. The en-
velope of each is triple
(fig. 522); and they
form a cavity lined by delicate filaments
which converge towards the centre, where

Crucibulum vulgare.

A conceptacle detached
from the receptacle.

Magnified 12 diams.

Fig. 522.

Cyathus vernicosus.

A nearly ripe receptacle, cut open vertically, showing
the two halves filled with conceptacles.

Magnified 3 diameters.

their extremities are expanded into lasidia
crowned by four spores (fig. 523), which
are cylindrical and almost sessile. The
filaments being of very unequal length, the

NIDULARIACE1.

[ 542 ]

NITOPHYLLUM.

basidia are intermingled with them in the
cavity of the conceptacle, not forming a
definitely marked layer.

Fig. 523.

Cyathus striatus.

Basidia and spores from the fertile layer of i
conceptacle.

Fig. 524.

Magnified 250 diameters.

Fig. 525. Fig. 526.

Cyathus striatus.

Fig. 524. Vertical section of a young receptacle. Magn.

10 diams.

Fig. 525. Another, more advanced. Magn. 10 diams.
Fig. 526. Another, still more advanced. Magn. 5 diamg.

Synopsis of British Genera.

* CARPOBOLI. Peridium containing only
one conceptacle.

Atractobolus. Perid. simple, cup-shaped,
sessile, closed at first by an umbonate lid.
Conceptacle spindle-shaped, simple, indehis-
cent, projected when ripe from the bottom
of a peridium.

Thelebolus. Perid. simple, sessile, round-
ish, urceolate-inflated ; mouth entire. Con-
ceptacle globose, papilliform, protruded
from the mouth.

Sphfsrobohis. Perid. double, each layer
bursting in a stellate manner, the internal
membrane at length turned inside out, and
projecting the globular conceptacle elasti-
cally.

Peridium with many

* NIDULARINI.
conceptacles.

Crucibulum. Perid. at first globose-capi-
tate, afterwards crucible-shaped, orifice ex-
posing numerous disk-shaped smooth concep-
tacles, each with a globular process beneath,
prolonged into a long, slender funiculus.

Cyathus. Perid. at first obovate or fusi-
form, closed by a veil, then widely open
at the mouth, exposing ten to eighteen
disk-shaped thick conceptacles, umbilicate
beneath, and attached to the walls of the
peridium by a compound peduncle.

Nidularia. Perid. sessile, subglobose,
finally open without evident veil ; concep-
tacles numerous, disk-shaped, nestling in
gelatinous mucus, without a funiculus.

BIBL. Tulasne, Ann. Sc. Nat. 3 ser. i. 41 ;
Schmitz, Linntea, xvi. 141 ; Sachs, Bot.
Zeit. xiii. 823 ; Pringsheini, Jahrb. ii. 199 ;
Eidam, Colin. Beit. ii. 221.

NIPHOB'OLUS, Kaulf.— A genus of Po-
lypodiaceous Ferns, with elegantly articu-
lated veins and numerous naked sori at the
tips of free branchlets ; under surface with
woolly tomentum. = Potypodium pt. (Hook.
Syn. 349).

' NIR'MUS, Nitzsch.— A subgenus of Phi-
lopterm. Like Docophortts, but the trabe-
culae absent or rudimentary. On the black-
cock, grouse, and pigeon.

NITELLA. See CHARACEJE.

NITOPHYL'LUM, Greville.— A genus
of Delesseriacese (Florideous Algse), con-
taining about half-a-dozen British species,
only two of which are commonly met with.
Their fronds are membranaceous, of reticu-
lated (parenchymatous) structure, mostly
rosy red, without ribs, or with irregular ribs
towards the base. The membranously ex-
panded frond of N. punctatum (PI. 4. tig. 6),
4 to 12" high, is either regularly dichoto-
mously divided or parted into two or three
principal lobes, which have a border of
dichotomous wedge-shaped lobes. N. lace-
rum has the frond 2 to 10" high, much
dichotomously divided and marked with
flexuous veins, the segments mostly linear,
waved or fringed at the margins. Fructifi-
cation consisting of spores, tetraspores, and
antheridia. 1. Spore. s sessile on the fronds,
arising from tufted filaments contained in
coccidia ; 2. tetraspores, forming distinct
scattered spots on the frond ; 3. antheridia,
minute cells standing perpendicularly on the
surface of the frond, collected into patches,
only distinguishable by the help of the
microscope.

NITRATE OF POTASH. [ 543 ]

NOCTILUOA.

BIBL. Harvey, Mar. Alg. 116, pi. 15 B ;
Phyc. Br. ; Greville, Alg. Br. pi. 12 j Thuret,
Ann. Sc. Nat. 4 ser. iii. 22.

NITRATE OF POTASH. See POTASH,
Nitrate of.

NITRIC ACID is useful as a reagent,
and for separating the organic matter of the
Diatomacege from the siliceous valves.

NITZSCH'IA .— A genus of Aunulata.

BIBL. Johnst. Non-parasitic Worms,
1855.

NITZSCH'IA, Denny (Liotheum).— A
genus of Anoplura.

N. Burmeisteri is the louse of the com-
mon swift (Cypselus apus~).

BIBL. Dennv, Monogr. Anopl. 230.

NITZSCH'IA, Hass.— A genus of Dia-
tomaceae.

Char. Frustules free, single, compressed,
usually elongate, straight, arched, or sig-
moid, with a longitudinal, not median, ex-
ternal keel (?), and one or more longitudi-
nal rows of puncta ; suture in front view of
frustules not median.

The valves have no nodules; we have
not been able to satisfy ourselves of the
presence of the external keel ; upon the
portions of the valves forming the middle of
the side view of the frustules are one or two
longitudinal rows of slightly elongate dots
or puncta (PI. 17. fig. 10 d), often visible
under ordinary illumin. ; surface of valves
covered with smaller dots, mostly opposite
(not quincuncial) (fig. 10 d), invisible under
ordinary illumination.

The frustules and valves are either linear,
lanceolate, or of intermediate forms, some-
times constricted or beaked.

N. siymoidea (PI. 17. fig. 9 : a, side view;
&, front view) ; length 1-75" ; freshwater.

N. lanceolata (PL 17. fig. 10: «, front
view of frustule ; 6, front view of single
valve ; c, side view of frustule) ; length
1-150" ; fig. 10 d exhibits the two kinds of
markings as seen with the stops. Marine.

N. birostrata, Sm. (PL 17. fig. 11 : a, side
view ; b, front view) ; length 1-70" ; ma-
rine.

N. adcularis (PI. 17. fig. 136); length
1-300"; freshwater.

N. reversa (PL 17. fig. 12); brackish
water.

N. tcenia (PL 17. fig. 13 a) ; length
1-250" ; brackish water.

BIBL. Smith, Br. Diat. 37; Hassall,
Alga, 435 ; Rabenh. Alg. i. 149.

.NOBERT'S LINES and PLATES.—
These consist of parallel bands or groups of

parallel lines, beautifully ruled upon a slide
with a diamond. The bands are of equal
breadth, and the lines in each successive
band are more numerous and closer than in
those of the preceding. In the 20-band
plate, R. Beck determined the distances of
the lines to be as follows, in fractions of an
inch.

Band.

1. l-13000th

2. l-15000th

3. 1 -18000th

4. l-21000th

5. l-23000th

6. l-27000th

7. l-31000th

8. l-36000th

9. l-41000th
10. l-45000th

Band.

11. l-49000th

12. l-52000th

13. l-55000th

14. l-57000th

15. l-59000th

16. l-61000th

17. l-63000th

18. l-65000th

19. l-67000th

20. l-70000th

More recently, a 30-band plate has been
produced, in which the lines are ruled to
over 1-100, 000th of an inch. The exhibition
of these lines requires sufficient magnifying
power, oblique illumination, and large' an-
gular aperture in the object-glass. See
TEST-OBJECTS. Also Frey, Mikr. • Pigott,
Mn. M. Jn. ix. 63; Robin, Mic. 313 ; Brown,
Pr. Roy. Soc. xxiii. 531 (Mn. M. Jn. xv.
273) ; Rogers, Mn. M. Jn. xvi. 74 ; Webb,
ibid. xvi. 171 ; Beck, Micr. 1865. 19.

NOCTILU'CA, Suriray.— A genus of
marine Protozoa, now usually referred to
the Infusoria.

N. miliaris (PL 53. fig. 23) is rounded, of
about the size of a pin's head, with a ten-
tacle-like, transversely striated, curved pro-
process, by means of which it propels itself
through the water. Near its attachment is
the mouth, on one side of which is a tooth-
like projection. The mouth leads by means
of a tubular gullet to an irregular hollow
stomach in the sarcode of the interior of the
animal ; and there is a definite anal opening.
The body consists of a radiating protoplas-
mic network. There is a nucleus; but no
vacuoles have been observed. The part to
which the tentacle is attached is plicate and
depressed, so as to render the body some-
what bilobed ; it has no carapace.

Multiplication takes place by subdivision
and internal gemmation. Sexual union
also takes place, the animals placing their
oral apertures close to one another, a proto-
plasmic bridge being formed, which unites
the nuclei of the two individuals ; the two
Noctilucae then fuse, and the nuclei become

NODOSARIA.

[ 544 ]

NOSTOC.

one. At last a large individual represents
the two. Swarm-spores, which become
tailed, ciliated, and furnished with the tooth-
process, are formed within the conjugated
Noctilucae and escape.

It is phosphorescent, rendering the sea
luminous by night ; but under the micro-
scope the luminosity does not appear to be
uniform, but dependent upon a number of
repeated flashes j it is increased by physical
and chemical agents.

BIBL. Quatrefages, Ann. So. Nat. 3 se"r,
xiv. ; Gosse, Nat. Ramb. ; Krohn, Wieg-
manri's Archiv, 1852; Huxley, After . Jn.
1855; Brightwell, Ann. N. H. 1850, vi.
305 ; Pring, Phil. Mag. 1849 ; Cienkowski,
Schultze's Archiv, 1871 & 1872 ; Carus, Man.
Zool. ; Webb, Qu. Me. Jn. iii. ; Busch, Qu.
Mic. Jn. iii. ; Allman, Qu. Mic. Jn. 1872,
326; Kent, Inf. 397.

NODOSA'RIA, Lamk.— A subgenus of
Hyaline Foramiiiifera. Shell elongate,
straight, rounded, conical or cylindrical,
with distinct or close-set chambers, smooth,
ridged, or spined; orifice terminal, mostly
produced and round (N. raphanm, PI. 23. fig.
29). It passes by curvature into Dentalina
&c., by eccentricity of aperture into Mar-
ginulina &c., and by compression into Lin-
gulina and Frondicidaria.

Found in Carboniferous and Permian
rocks ; abundant in the Trias and Lias, and
in many strata of later date : living in many
seas in rather deep water.

BIBL. D'Orbigny, For. Foss. Tien. 38;
Williamson, Rec. For. 14 ; Morris, Cat. Br.
Foss. 37 ; Parker and Jones, Ann. N. H. 3.
iii. 478 ; Carpenter, For. 161.

NODOSARI'NA, P. & J. — A genus
(strictly a type species) of Hyaline Fora-
minifera. Its chief subgroups are Nodosaria
and Cristellaria, which are one in essential
characters of structure and mode of growth:
GlanduUna, Lingulina, Dentalina, Rirmdina,
Vaginulina, Marginulina, Flabellina, Fron-
dicularia, and others are subsidiary forms.
No line of division can be drawn between
these approximate allies; for the straight,
the curved, and the spiral lose themselves
in each other — the amount of curvature and
of spirality, and the greater or less closeness
of the chambers and of the whorls being
varying characters. The style of ornament,
chiefly longitudinal ribbings, passing into
spines and tubercles, is the same throughout
(see PI. 23. figs. 28 to 39).

BIBL. Parker and Jones, Ann. N. H. 3.
iii. 477 ; Carpenter, Foram. 159.

NODOSINEL'LA, Brady.— One of the
Arenaceous Foramiiiifera, being a Lituoline
isomorph of Nodosaria. Fossil in the Car-
boniferous and Permian rocks. (Bradv,
Monogr. Carb. For., Pal. Soc. 1876.)

NODULA'RIA =Lemanea. — Supposed
to produce poisonous effects. (Beale, How,
£e.281.)

NCEMATE'LIA, Fr.— A genus of Tre-
mellini (Hymenomycetous Fungi) distin-
guished bv the presence of a central nucleus
distinguished from the gelatinous surround-
ing substance. N. encephala is common in
subalpine countries on larch rails, looking
like a small brain, as the name implies.

BIBL. Fr. Ep. 591 ; Berk. Outl. 290 ;
Cooke, Handb. 350.

NOLEL 'LA, Gosse. — A genus of Inf un-
dibulate Ctenostomatous Polyzoa, of the
family Vesiculariidoe.

Distinguished by the erect, subcylindrical
cells, crowded on tubes forming an unde-
fined incrusting mat ; tentacles eighteen,
forming a bell. One species :

N. stipitata.

BIBL. Gosse, Mar. Zool. ii. 21.

NONIONI'NA, D'Orb.— A subgenus of
Hyaline Forarnmifera, subordinate to Poly-
stoineUa. Shell nautiloid, usually sym-
metrical ; many chambers, opening with a
transverse slit at the base (N. crassula, PI.
24. fig. 18). By septal modifications it passes
into Polystomella (P. striato-punctata, and
P. crispa, PL ?4. figs. 19, 20).

Nonionina is not known for certain in
strata older than the Chalk and the Tertiaries.
It still abounds in shallow seas of temperate
latitudes.

BIBL. D'Orbigny, For. Foss. Vim. 109 ;
Parker & Jones, Ann. N. If. 3. v. 102 ; Car-
penter, For. 286.

NORMANDI'NA, Nyl. — A genus of
Pyrenodei (Lichenaceous Lichens).

Char. Thallus squamose, squamulae thin,
rounded; apothecia black, immersed. N.
ketevirens, green, common on damp earth.

BIBL. Leigh ton, Lich. Flora, 440.

NORMANEL'LA, Brady.— A genus of
Copepodous Entpmostracea. N. dubia,
North Sea. (Brady, Copep. ii. 87.)

NOSTOC, Vaucher.— The typical genus
of the Nostochaceae, distinguished from the
allied genera by the definitely formed hard-
ened pellicle or rind enclosing the fronds,
which are composed of a gelatinous sub-
stance (fig. 527) in which are imbedded
numerous more or less beaded filaments
(fig. 528). The filaments are composed of

NOSTOC.

[ 545 J

NOSTOC.

rows of cells (PI. 8. fig. 7) which increase
the length by repeated transverse sub-
Fig. 527.

K"ostoc commune.
Natural size.

division; here and there are larger cells
(«, c) which appear brighter than the rest,
resembling the vesicular cells of the allied
genera. The filaments break up after a
time into short fragments, which by cell-

Nostoc caDruleum.
Filaments. Magnified 200 diameters.

division produce new filaments. The pelli-
cle of the frond bursts, allowing the gela-
tinous mass to escape, and the filaments to
spread abroad in the water ;
tnese consist of short straight- Fig. 529.
ish pieces, which move slowly
along in the direction of their
length; after a time they cease
to move, and a new gelatinous
envelope is formed around each
piece like a transparent sheath.
They soon become enlarged
considerably, and then divide
in the direction of the length of
the filament (fig. 529), which
becomes so disintegrated that
the filament forms a spiral,
by the increase of which
through further transverse
cell-division the mass be-
comes confused, until the de-
velopment of a greater quan- Ma8glSdiams.
tity of the gelatinous matter
makes the filaments more distinct.

The British species of this genus are

Nostoc
verrucosum.
Filaments mul-
tip
sut

found on damp ground, wet rocks, mosses,
&c., and free or attached to stones, in
fresh water (PI. 8. fig. 7). They are very
numerous, and the following only can be
noticed.

* Frond globose or subglobose.

Nostoc minutissimum. Frond globose,
from 1-30 to 1-4'" ; filaments equal, deep
seruginous green, densely entangled j peri-
derm growing brown.

N. lichenoides. Fronds from the size of
a mustard-seed to that of a pea, aggregated
and heaped together; filaments equal,
loosely entangled, seruginous or olivaceous ;
periderm pellucid, colourless, firm.

(3. vesicarium; larger, soft, with a fuscous
distinct periderm, mucous within, some-
times hollow.

N. sphcericum. Frond the size of a pea,
firm, blackish seruginous or somewhat olive-
coloured, soft within ; filaments pale green,
loosely entangled ; periderm firm, colourless
or fuscescent, subopaque. On stones in
mountain rivulets. Meneghini states that,
when dried and again moistened, it emits a
pleasant odour like violets. Hassall thinks
it probably an immature form of N.foli-
aceum.

2V. cceruleum. Frond from the size of a
pea to that of a sloe, soft and slimy, pale
seruginous blue ; filaments unequal, loosely
entwined, joints oblong-elliptical ; periderm
colourless,' pellucid, soft. On mosses in
flowing water or very moist places.

N. pruniforme. Frond the size of a large
round plum, deep aeruginous green, very
soft and watery within ; filaments unequal,
bright aeruginous green, loosely entangled,
joints subdepressed, dimidiate ; periderm
leathery, crystalline ; unattached, in fresh-
water pools or rivulets.

** Frond foliaceotis, irregular, or vesicular.

N. foliaceum. Frond terrestrial, mem-
branous, erect, plaited, olive-green; fila-
ments slender, copious. On clayey ground
constantly moistened by oozing water.

N. commune (fig. 527, & PL 8. fig. 7).
Frond terrestrial, gelatinous, subcoriaceous,
greenish, irregularly plaited; filaments
nearly equal, flexuous, colourless or green,
loosely entangled, the joints loosely con-
joined, distant or geminate, subspherical,
depressed, with a central opaque spot ;
periderm hyaline, growing brown. Gravelly
soils, garden walks, rocks, barren pastures,
&c. ; very common in autumn and winter.

NOSTOCHACE.E.

[ 546 ]

NOTODELPHYS.

N. verrucosum, Vaucher. Frond blad-
der-shaped, softly leathery, fuscous-green ;
filaments spiral, densely entangled, joints
globose ; periderm gelatinous, soft, green
or dirty brown. On stones in streams.

N. variegatum, Moore.

BIBL. The works above quoted; Itzig-
sohn, Bot. Zeit.TLii.SZl (1854); Sachs, Bat.
Zeit. xiii. 1 (1855) ; Thuret, Mem. Societt
de Cherbourg, 1857, Ann. N. H. 3 ser. ii. 1;
Kiitzing, Sp. Alg. 295, and Phyc. gen. 204 ;
Fischer, Nostoc. 1853 ; Hicks, Qu. Mic. Jn.
1861, ii. 90 ; De Bary, Regensb. Fl. 1863 ;
Rabenh. Alg. ii. 161.

NOSTOCHA'CE^E.— A family of Con-
fervoid Algae, forming gelatinous strata or
definitely shaped gelatinous balls or masses,
on damp ground or floating at the bottom
of water; consisting of minute, unbranched,
usually moniliform, microscopic filaments,
tranquil or oscillating, imbedded in a mass
of mucilaginous or firmish substance (the
amorphous matrix is produced by the fusion
of the gelatinous sheaths of the individual
filaments); filaments finally breaking up.
Cells of the filaments of three kinds:—!.
ordinary cells ; 2. vesicular cells or hetero-
cysts, usually large and without granular
matter, frequently with erect hairs ; 3. spo-
rangia or sporangial cells, produced by the
enlargement of the ordinary cells, globular,
elliptical or cylindrical. Reproduction by
spores has been observed in Cylindrosper-
mum by Thuret, who finds that the spo-
rangial cells produce in their interior one
thick-coated spore, which, after a season of
rest, germinates and breaks out from the
sporange to grow into a new cellular fila-
ment.

Synopsis of British Genera.

Nostoc. Phycoma globose or spreading,
gelatinous or coriaceous, containing simple,
curved, and entangled, moniliform, colour-
less or greenish filaments, composed of cells
imbedded in a gelatinous matrix ; hetero-
cysts globose, interstitial, larger than the
other joints.

Monormia. Frond a gelatinous, elon-
gate, curled and convolute sheath, enclosing
a single moniliform filament ; heterocysts
interstitial ; sporangia developed from j rants
most distant from the vesicular cells.

Trichormus. Heterocysts interstitial and
terminal. Sporanges at first formed from
the cells most distant from the heterocysts.

Sphcerozyga. Heterocysts interstitial ;
sporanges from the nearest cells.

Cylindrosporum. Heterocysts terminal ;
sporanges like the last.

Dolichospermum. Heterocysts interstitial ;
sporanges of unequal length, and without
definite arrangement.

Aphanizomenon. Heterocysts none (?) ;
sporanges usually simple and of unequal
length.

Spermosira. Heterocysts interstitial,
single or in pairs ; sporanges as in Trichor-
mus.

Exotic genus : Trichodesmium.

BIBL. Ralfs, Ann. N. H. 2 ser. v. 321 ;
Kiitz. Tab. Phyc. i. 91 ; Thuret, Ann. Sc.
Nat. 2 se>. ii. ; Meneghini, Mem. Turin
Acad. ser. 2. v. 1843 ; Allman, Mic. Jn.
1855; Rabenh. Alg. ii. 161; M'Nab, Qu.
Mic. Jn. 1874, 215*; Sachs, Hot. 251.

NOTA'MIA, Flem — A genus of Gernel-
lariidse, Cheilostoinatous Polyzoa.

Char. Cells placed back to back, facing
opposite directions ; tobacco-pipe-shaped
bird's-heads above each pair. One species :

N. bursaria (PI. 36. fig. 21). An elegant
microscopic object.

BIBL. Johnston, Br. Zooph. 294 ; Busk,
Cat. Polyz., Brit. Mus., 36; Hincks, Polyz.
99.

NOTAS'PIS, Herm.— A genus of Ori-
batea (Acarina). Cephalothorax with
lamellar appendages, tarsi with three
homodactyle claws. N. bipilis, common in
France. (Murray, EC. Ent. 217 ; Michael,
Jn. Mic. Soc. 1880, 177.)

NO'TEUS, Ehr.— A genus of Rotatoria,
of the family Brachionsea.

Char. Eyes absent, foot forked ( = eye-
less Brachionus).

N. quadricomis (PI. 44. fig. 13). Carapace
suborbicular, depressed, scabrous, areolate,
with four spines in front and two behind ;
freshwater ; length 1-10 to 1-70".

BIBL. Ehr. Infus. 602; Pritch. Infus.

NOTH'RUS, Koch.— A genus of Ori-
batea (Acarina). Cephalothorax without
lamellar appendages, tarsi with three hete-
rodactyle claws. N. spiniger, violet-brown,
covered with dirt. N. horridus, in moss.
(Murray, EC. Ent. 219.)

NOTOCHL^E'NA, Brown.— A genus of
Grammitideae (Polypodiaceous Ferns).
Several species; tropical. (Hook. Sun.
370.)

NO'TOCHORD.— The new name for the
Chorda dorsalis.

NOTODEL'PHYS, Allm.— A genus of
Copepodous Entomostraca.

NOTODROMAS.

[ 547 ]

NUCLEUS.

N. ascidicola (PI. 19. fig. 22) resembles
Cyclops in general appearance. The ex-
ternal ovary is a single organ, lying across
the back of the abdomen ; eye single j
marine.

3 other species.

BIBL. AUman, Ann. N. H. xx. 1 ; Baird,
Br. Entom. 237 ; Brady, Copep. i. 141.

NOTOD'ROMAS, Lilljeborg.— An Os-
tracode related to Candona, among the Cy-
pridce. It has long setae on the lower an-
tennae, and two eyes. Its carapace has a
flat ventral surface with limiting ridges;
and with this portion upwards it floats at
the top of sunny pools in Europe and the
British Isles (N. monachus, Miiller), and in
Australia (N. fenestrata, King).

BIBL. Brady, Linn. Tr. xxvi. 379.

NOTOGO'NIA, Perty.— A genus of Eu-
chlanidota (Rotatoria).

Char. Lorica present, dilated posteriorly,
with two pointed processes on each side.
Eyes two, red; jaws curved, strong, with
two or three teeth; caudal setse strong;
between Confervas.

BIBL. Perty, Lebensf. 42.

NOTOM'MATA, Ehr.— A genus of Ro-
tatoria, of the family Hydatinaea.

Char. Free ; eye single, cervical ; tail-
like foot with two toes; rotatory organ
simply ciliated.

In some the rotatory organ is extended
laterally in an ear- or arm-like form.

Ehrenberg describes twenty-three species,
some of which are parasitic, N. petromyzon
and parasita living within Volvox globator,
and N. Werneckii within the vesicles of
Vaucheria ; and divides them into the sub-
genera : — Labidodon, jaws each with a
single tooth ; Ctenodon, jaws each with
several teeth.

Notommata granularis is the male of N.
Brachionus.

Many of the species are large and well
adapted for the study of the internal
structure.

N. centrura (PI. 44. fig. 14 ; 15, jaws and
teeth). Body attenuate at each end, foot
small and hard ; cephalic auricles short ; no
lateral setae ; freshwater ; length 1-36".

BIBL. Ehr. Inf. 424; Duj. Inf. 646;
Pritchard, Infus. 681 ; Hudson. M. M. Jn.
1875.

NOTONEC'TA, L.— A genus of aquatic
Hemipterous insects.

The insects belonging to this genus have
the elytra membranous in the posterior part,
and the body is more or less boat-shaped.

Fig. 530.

Notonecta glauca.
Magnitied 3 diameters.

The hind legs are very long, and when
stretched out resemble and act as a pair of
oars. The Notonectce swim on their backs,
and generally in a slightly inclined position,
on the surface of ponds and ditches. They
descend with great rapidity. They are
very voracious, and live on aquatic larvae,
biting also very sharply. Their mouth-
organs and limbs afford interesting micro-
scopic objects.

N. glauca (the water-boatman) is com-
mon in pools.

NOTOPTEROPH'ORUS, Costa. — A
genus of Copepodous Entomostraca. Two
species ; marine. (Bradv, Copep. i. 141.)

NUBECULA'RIA, Defrance.— An Im-
perforate Foraminifer ; shell opaque, often
sandy, protean, parasitic on shells and algae ;
straight, scale-like, or cervicorn ; chambers
with imperfect base ; at first spiral ; aperture
oval, produced, often lipped. Fossil in the
Trias, Oolite, and Tertiaries; common in
shallow waters of warm latitudes (N. ruaosa,
PL 23. fig. 21).

BIBL. Jones & Parker, Q. J. Geol. Soc.
xvi. 455 ; Carpenter, For. 69.

NUCLEUS AND NUCLEOLUS OF
ANIMALS. See CELL, p. 138.

NUCLEUS and NUCLEOLUS OF
PLANTS. — The term nucleus is applied in
botany to two very different things — first
to the central body of the young ovules of
Flowering plants, and secondly to a pecu-
liar structure met with in the interior of
cells. The first will be described under the
head of OVULE ; the cell-nucleus and nu-
cleolus are treated of in the article CELL,
Vegetable.

Few parts of the minute organization of
plants are more obscure than the structure
and function of nuclei : some authors re-
gard them as of the highest physiological
importance; others consider their import
2N2

NUCLEUS.

[ 548 ]

NUCLEUS.

altogether unknown. The nucleus may be
observed most easily in the parenchymatous
cells of the herbaceous structures and flowers
of Monocotyledons (PI. 46. fig. 28 6), or in
the young cells of the hairs of Flowering
plants generally (PI. 47. figs. 8, 96), or in the
embryo-sacs of ovules (PI. 47. figs. 4-6) ;
in such cases the characters are well defined
and unmistakable. It consists of a lenti-
cular body formed of more or less granular
Srotoplasm, with one or more well- or ill-
etined bright points or cavities (nucleoli} in
the interior. Wherever it appears throughout
the higher plants, it seems to possess the
eaine characters ; but it may be absent in
the cells of many Algae, Lichens, and
Fungi.

Ordinarily nuclei are found attached to
the side of cells, or forming the centre of
radiating protoplasmic filaments (PI. 47.
fig. 9) : sometimes, however, the nucleus is
suspended in the middle of the cavity of
the cell by filamentous processes of proto-
plasm ; in all such cases it forms a kind of
centre for the circulation of the protoplasm
where this exhibits movement (ROTATION),
and it is itself carried about to a certain
extent by the currents.

The nucleoli (PI. 47. fig. 8 ri) of these
larger nuclei are apparently usually more or
less solid granules of a transparent substance,
but sometimes they appear more like minute
cavities.

The nuclei and nucleoli of the lower
plants are exceedingly obscure ; in a great
many cases the so-called nuclei are little
different from the nucleoli of the larger
forms, occupying to the entire cell-contents
the same relation as the nucleoli to large
nuclei, for example, in the spores of Lichens
(PI. 37. fig. 7), Fungi, &c. In the lower
Confervoid Algae the nucleus (or nucleolus)
appears to be represented by the entire cell-
contents (PI. 7), in which one or more well-
defined granules often occur, representing
nucleoli; in certain stages, however, a larger
granule is met with, coloured by chloro-
phyll, which some regard as a nucleus ;
this disappears totally at particular epochs,
and is replaced by starch-granules or oil-
globules. The bright-coloured point, or
" eye-spot," seen very generally in the ZOO-
SPOKES both of Confervoids and Fucoids,
may represent a nucleolus.

Nuclei originate in two ways. The sim-
plest mode is found where they precede free-
cell formation, as in the development of
the germinal vesicles in the embryo-sacs of

Flowering plants. Here the nuclei appear
first as globular, granular, or lenticular
masses, which become gradually defined in
the substance of a collection of protoplasm
accumulated at the upper end of the cell
(PI. 47. tigs. 1-4). This is a spontaneous
isolation of a portion of the protoplasm to
become the foundation of a new cell. We
may compare this with the segmentation of
the entire mass of contents of the cells of
Confervee in the formation of ZOOSPORP:S,
which may perhaps be regarded as at
first free nuclei. In cells multiplying by
division, a division of existing nuclei has
been observed to take place in certain cases,
as in the hairs of Tradescantia (PL 47. tigs.
8 & 9) ; but in other similar cases of division
no nuclei are observed (PI. 47. figs. 10 & 11).
In Tradescantia, the oval parent nucleus fills
up the end of the growing cell, so that the
division of the nucleus is almost synonymous
with the division of the primordial utricle.
But in this case, as in the development 01
cells from free nuclei, as indicated in the
germinal vesicles, the cell-membrane in
expanding draws away from the nucleus,
which remains adherent to or suspended in
connexion with a layer of protoplasm lining
the cell-wall and forming its primordial
utricle. In SPIROGYRA and Zi/ffnema, a
division of the free suspended nucleus pre-
cedes the division of the large primordial
utricle.

Mohl describes a division of nuclei as
occurring in Anthoceros ; and most authors
who have written on the development of
pollen and spores lay great stress on the
influence of the nuclei, which they describe ;
but the import of nuclei in vegetable cells
is certainly still a problem. Some believe
they are the universal agents of production
of new cells ; others that they are not the
agents of this in any case, but, when pre-
sent, may be divided with the cells. Others
imagine that they are merely the original
" mould " of protoplasm on which the cel-
lulose membrane of the nascent cell is de-
posited, and which is left unaltered when
this expands (the phenomena in Spirogyra
are opposed to this). Some of those who
deny their influence in cell-development
believe them to be the vital centres of the
cells in which they exist.

They are best seen in very young cells in
all cases ; in nascent tissues they almost or
quite fill the cavity of the young cells. As
the cells grow older, their history differs in
different cases. Sometimes they persist

NUMMULINA.

[ 549 ]

ODONTELLA.

until the decay of the organ in which they
exist. This happens very generally in the
cells of the flowers, stems, &c. of Monoco-
tyledons ; not uufrequently, in stems and
leaves they become converted into starch or
chlorophyll granules. In other cases they
have a more definite purpose; for in the
vesicles in which are formed the SPERMATO-
ZOIDS of Ferns, Mosses, Hepaticae, Chara-
ceee, &c., these structures appear to be pro-
duced by a metamorphosis of the nuclei.

In examining supposed nuclei of plants,
especially those of lower cellular organiza-
tion, tincture of iodine should always be
applied, to distinguish starch-granules &c.
from true nuclei, which are always coloured
deep yellow or brownish by that reagent,
besides being coagulated, contracted, and
thereby rendered more distinct.

BIBL. R. Brown, Phil. Mag. Dec. 1831;
Nageli, Zeit. iviss. Bot. (Ray Soc. 1845 &
1849); Mohl, Pflanzenzelle, 36, 51; Hof-
meister, Entsteh. d. Embryo, 1849, 7; Braun,
Verjunguny (Ray Soc, 1853, 175); Sachs,
Bot. 45 ; Strassburger, Zellenbildung, 1880.

NUMMULI'NA, D'Orb. I A Hyaline Fo-

NUMMULI'TES,Lamk. j raminifer of
the highest class. Shell lenticular, varying
in convexity and in size (from less than Jg-
to 2^ inches in diameter), composed of
several, overlapping, uniform, whorls of nu-
merous > -shaped chambers in a discoid
spire. These are prolonged towards the
umbo of each face, thus forming Alar
Lobes, either straight (in the Radiatce),
or sinuous (Sinuatce), or inosculating (Reti-
culates). The alae are abortive or absent,
and the spire therefore exposed, in Assilina
and Operculina, unequal and modified in
Amphistegina. The chambers communicate
bv a transverse slit at the base of the
septum, with smaller occasional holes. The
outer chamber-walls (Spiral Lamina) are
thin in the latest, but in the older cham-
bers thickened by successive layers of the
delicate tubuliferous shell. Over the septa
of the median plane (PL 24. fig. 22), and
where the alar septa cross and touch, the
tubuli being obsolete, the shell becomes
translucent (Pillars) ; at the outer margin
(Marginal Cord) also of the whorls the
layers of shell become translucent, and are
traversed by radiating and inosculating
tubes, continuous with canals passing be-
tween the two shell-layers of each septum
(Interseptal Canals), and with the canals
in the margin of the inner whorls. This
Canal-system carries spiral and branching

threads of sarcode through the denser parts
of the shell, which, indeed, in some Polysfo-
meUce and Ccdcarinte appear to be secreted
thereby (Supplementary Skeleton).

Nummulina is rare in the Carboniferous,
Jurassic, and Cretaceous, but very common
in the Lower Tertiary strata ; living in the
North, Red, and Australian seas, but small
(N. radiata, PL 24. fig. 21).

BIBL. D' Archiac et Hairne, An.foss. Num.
Inde, 1853; Carter, Ann. N. H. ser. 2. xi.
161, ser. 3. viii. 320, 366 ; Parker and Jones,
Ann. N. H. ser. 3. v. 106, viii. p. 229 ; Car-
penter, Foram. 262, Microscope, 1858, 510 ;
Brady, Ann. N. If. ser. 4. xiii. 222.

NYCTOTHE'RUS, Leidy.— A genus of
Heterotrichous Infusoria, very near Playio-
toma. 4 species ; in the intestines of Am-
phibia and Invertebrata. (Kent, Inf. 579.)

NYMPELEACE.E. See HAIBS (p. 379).

O.

OAT, Avena sativa (Nat. Order Grami-
nacese, Flowering Plants). — The form of
the starch-corpuscles of the oat is very un-
like that of the other common corn-plants ;
they consist of numerous small polygonal
grains grouped together in roundish or oval
masses (PL 46. fig. 10). See STABCH.

OBE'LIA=Zaom<?cfea pt.

OBISIDA. See ARACHNIDA.

OBJECT-GLASS, or OBJECTIVE. See
INTRODUCTION, p. xvi. & ANGULAR APER-
TURE, p. 47.

OCEL'LI. — The simple eyes or eye-spots
of the Invertebrata ; they are noticed under
the classes.

OCHLOCH^ETE, Thwaites.— A genus
of Chsetophoraceae. O. hystrix, on grasses
in freshwater and brackish ditches.

OCHROP'TERIS, Sm.— A genus of
Pteridese (Polypodiaceous Ferns). O. pal-
lens-, Mauritius. (Hook. Syn. 127.)

OCTAVIA'NA, Tul.— A genus of Gas-
teromycetous Fungi (section Hypogaei) dis-
tinguished by the sterile base of the conti-
nuous or cracked peridium; the easily
divisible byssoid frames and the fruit-
bearing cavities at first empty, then covered
with the rough spores.

BIBL. Tul. Fung. Hyp. t. ii. f. 1 : Berk.
Outl. 292 ; Cooke, Handb. 355.

OCTOSPORES.— Sporangia of Fucaceze,
which subdivide into a cluster of eight cells.

ODONTEL'LA, Ag. — This genus of
Diatomacese is united with BIDDULPHIA,
Biddulphia (Odontelld) aurita undergoing
spontaneous division, PI. 19. fig. 9.

ODONTHALIA.

[ 550 ]

(EDOGONIUM.

ODONTHA'LIA, Lyngb.— A genus of
Rhodomelaceae (Florideous Algae) contain-
ing one British species, O. dentata (PI. 4.
fig. 13), which has an irregularly bipinna-
titid frond, 3 to 12" long, the main axis and
lobes 1-4" wide throughout ; colour deep
wine-red, darker when dried. Frond with
marginal, stalked, ostiolate, ovate ceramidia
with spores, lanceolate stichidia, in which are
contained two rows of ternate tetraspores,
and aniheridia.

BIBL. Harv. Alg. 77, pi. 11 A; Phye. Br.
pi. 34; Greville, Alg. Br. pi. 13, Kiitz. Phyc.
generalis^ 448.

ODONTID'IUM, Kiitz. — A genus of
Diatoinaceae.

Char. Frustules quadrangular, united into
an elongated biconvex filament; linear in
front view; valves elliptical with transverse
continuous striae. Freshwater and marine.

Differs from Dentioula in the elongated
filament, which sometimes, however, con-
sists of only three or four frustules !

O. turyidulum (PL 17. fig. 14 : o, front
view; 6, side view). Valves lanceolate,
obtusish; striae on each valve six; fresh-
water; length of frustules 1-1720 to 1-570".

O. tabellaria,Srmth = Staurosira construens,
Ehr. (PI. 50. fig. 38).

BIBL. Kiitz. Bacill. p. 44 ; Sp.Alg. p. 12 ;
Smith, Brit. Diat. ii. 15 ; Rabenh. Fl Eur.
Alg. i. 116.

ODONTODIS'CUS, Ehr.— A genus of
Diatomacese. See COSCINODISCUS.

Char. Frustules single, lenticular ; valves
circular, alike, without nodules, covered
with dots arranged either in radiating rows
or in excentrically curved lines, and with
erect marginal teeth. Three species; fossil
and in guano.

O. eccentricus (PI. 18. fig. 52).

BIBL. Ehr. Ber. Berl.Ak. 1844, 73; Kiitz.
Sp. Alg. 129 ; Pritchard, In/us.

ODONTOPHORE. — A new name for
the tongue of the Mollusca; and Radula is
another.

ODONTOTRE'MA, Nvl.— A genus of
Lecideinei (Lichenaceous JLichens).

Char. Thallus indistinct. Apothecia
black, thelotremoideo-lecideine or gymno-
tremoid, naked, at first closed, then dehiscing
with a denticulato-ruptured proper margin.

O. lonyius, Nyl. On old rails.

BIBL. Leighton, Lich. Flora, 389.

(ECIS'TES, Ehr.— A genus of Rotatoria,
of the family OEcistina.

Char. Single; rotatory organ single,
with an entire margin; body attached to

the bottom of a fixed cylindrical carapace ;
eyes two, frontal, red, disappearing in ad-
vanced age.

O. crystallinus (PI. 44. fig. 16). Carapace
hyaline, viscid, covered with foreign bodies;
freshwater; entire length 1-36".

Jaws each with three teeth.

BIBL. Ehr. Inf. 392; Pritchard, Inf.;
Davis, Mic. Tr. 1866, 14; Hudson, Jn. M.
Soc. 1881, 1.

(ECIS'TINA, Ehr.— A family of Rota-
toria (small Melicertte, probably).

Char. Animals single or aggregate, at-
tached to the bottom of a gelatinous cara-
pace ; rotatory organ single, with an entire
margin.

A distinct carapace for each animal. . . 1 . CEcittes.
Carapaces aggregated into a sphere... 2. Conochilut.

BIBL. Ehr. In/us. 301.

(EDE'MIUM, Fr.— A genus of Dematiei
(Hyphomycetous Fungi). GE. atrum, Corda,
consists of dense tufts of brown erect fibres,
scarcely branched, and without true septa.
The roundish " spores " are sessile upon the
sides of the erect filaments.

BIBL. Corda, Sturm's Devtschl. Fl. 6,
pi. 9 ; Fries, Syst. Myc. 344 ; Berkeley and
Broome, Ann. N. H. 2 ser. vi. 466.

(EDIPO'DIUM, Schwagr.— A genus of
Splachnaceae (Acrocarpous Mosses), some-
times included under Gymnostonmm. CEdi-
podium Griffithianum, Schwag., the only
species, is remarkable for the peculiarly
thickened fruit-stalk, whence the name of
the genus is derived.

(EDOGONIA'CE^E.— A family of fila-
mentous Confervoid Algpe, remarkable for
the filaments growing by a peculiar mode of
cell-division, accompanied by circumscissile
dehiscence of the parent cell, and by the
zoospores being formed from the whole con-
tents and bearing a crown of numerous cilia.
Two genera :

CEdogonium. Filaments unbranched.

Bulbochcete. Filaments branched and
bearing bristle-cells with a bulbous base.

BIBL. See the genera.

(EDOGO'NIUM,Lrnk. (B-o&/m*,Leclerc,
Vesiculifera, Hass.). — A genus of CEdogo-
niaceae (Confervoid Algas). Some (EcJoyc-
nia are among the commonest and most
abundant of freshwater Algae, occurring in
every pond, ditch, or stream, and quickly
making their appearance in tanks, aquaria,
&c. They may generally be recognized at
a glance by the dense and uniform green
protoplasm, sometimes filling the cells,
sometimes (after dividing) leaving half of the

(EDOGONIUM.

C 551 ]

(EDOGONIUM.

cell colourless and devoid of chlorophyll —
above all, by the annular striae occurring at
the ends of many of the cells (PI. 9. fig. 7 b,
h). The cells have each a large parietal
nucleus (fig. 7 «). The large round inter-
stitial sporangial cell (fig. 7 g) is also a very
distinctive character. The filaments are at-
tached, when young, to stones, plants, &c.
by root-like processes ; and are composed of
rows of cylindrical cells, which multiply
interstitially in a very curious manner.
When a cell is about to divide, an annular
deposit of cellulose occurs around the upper
part of the parent cell. Next the wall of
the parent cell breaks, by a circumscissile
dehiscence, just below the cellulose ring.
The internal cell elongates and removes the
margins of the circular slits from each other,
the upper piece of the parent-cell wall being
pushed up as a kind of cap on the elongating
cell. While the cell is thus being elongated,
its primordial utricle becomes divided below
the line of dehiscence of the parent cell ;
but both the new portions grow, so that the
line of division between the two new cells
at length rises above the margin of the
lower part of the parent cell. The annular
deposit of gelatinous cellulose has mean-
while become stretched or developed over
the space left by the separation of the halves
of the parent membrane, forming an outer
coat to the new cell. After the growth of
the lower cell is finished, the upper one
begins to elongate, until it attains equal
length ; it remains poor in protoplasm and
chlorophyll while growing, but becomes
densely filled when it has attained its full
dimensions. The margins or broken ends of
the parent-cell wall form the annular striae
seen on the filaments (PI. 9. fig. 7 b, g, h) :
at first there is only one at the top of any
given cell; but the next dehiscence takes
place just below this, giving rise to a second,
and so on, until many successive rings are
produced at one spot.

The zoospores or ciliated gonidia (fig. 7 c)
are formed from the entire contents of a
cell, and exhibit a large round nucleus;
fiey escape by a circumscissile dehiscence
of the wall of the parent cell (6) : the fila-
ment, however, does not generally become
quite broken in two ; the portions remain
attached by a strip of the side-wall forming
a kind of hinge ; and the zoospores are not
set free directly, but at first are enclosed in
a very delicate and almost imperceptible
globular envelope, colorable blue by iodine
and sulphuric acid, which appears to dis-

solve very quickly in the water. The zoo-
spores are large, somewhat ovate in form,
with a transparent region at one end, whence
the numerous cilia arise. When expelled,
they move for a time, and then come to rest,
attaching themselves to foreign objects by
the ciliated end, acquiring a membrane,
sending out root-like processes below (e),
and elongating and expanding above into a
longish pear-shaped body. Sometimes the
zoospores do not completely extricate them-
selves from the parent cell, and then ger-
minate in this way in situ, the root-like
processes remaining engaged in the parent
cell. Very often they attach themselves
upon the parent filament to germinate. The
next stage after germination presents two
different classes of phenomena : in the one
case, as a purely vegetative zoospore, the
young plant elongates gradually into a
jointed filament by extension and cell-
division ; in the other it is an androspore,
and becomes an antheridial filament.

The (Edogonia produce large resting-
spores (oospores or oogonia), which are
formed from the entire contents of the
uppermost of two cells developed as above
described. A rupture of the parent-cell
wall takes place at the side during the
development of the spores ; through the
small orifice thus formed the spore-mass
becomes fertilized through the agency of
the little globular bodies produced in the
antheridia (PL 5. figs. 5, 16, 17). Ulti-
mately the spore, while increasing in size,
retracts itself from the walls of its parent
cell (pogoniuni), and lies free in the cavity,
presenting a double coat, the outer of which
is thick and tough ; its contents acquire a
red colour as it ripens. The parent cell of
the spore mostly acquires a globular or
elliptical form, and a red or brown colour,
appearing like a kind of nodule on the fila-
ment ; and the ripe spore, of globular ellip-
tical, or depressed spherical form, is mostly
of greater diameter than the ordinary cells
(PI. 5. fig. 21). The ripe spore, which is
quadruple, escapes by the decomposition or
dehiscence of the parent cell, and is covered
with a hyaline membrane. Each of the
four spores is likewise surrounded by its
cell-membrane. After a short time has
elapsed, the hyaline membrane disappears,
and the four spores lie still and motionless.
Then a change sets in : the cell-membrane
of each spore bursts by means of an annular
slit, and a part separates like a lid. Soon
the cell- contents leave the cell in the form

(EDOGONIUM.

[ 552 ]

(EDOGONIUM.

of a zoospore, which moves with the aid of
a crown of cilia. Aiter a time the motion
ceases, the cilia disappear, and one end of
the zoospore becomes elongated into a root
like the ordinary zoospores. The little cell
thus fixed becomes divided by a transverse
septum. Each spore thus produces four
(Edogonium plants.

The antheridial structures of the (Edo-
gonia are either formed in the ordinary fila-
ments (PL 5. fig. 13), or from dwarf fila-
ments produced from the smaller zoospores
or androspores (PI. 5. fig. 19). In either
case they consist of one or more very short
joints of the filament, formed in the ordi-
nary way, the contents of which divide
into two portions. The cells then dehisce
and allow the new products to escape, which
resemble the vegetative zoospores, but are
much smaller. These new bodies, the
spermatozoids, make their way through the
orifices in the parent cells of the spores and
fertilize their contents (PI. 5. fig. 20).

Some of the larger spermatozoids move
like Amoeba, creeping over the oospore,
until they reach the canal, into which
they enter.

The (Edogonia appear to be sometimes
purely monoecious or dioecious, the single
filaments including either both antheridial
and spore-cells, or only one kind of organ ;
but the most common condition is interme-
diate : the filaments having some joints
converted into sporangial cells, others
giving birth to the androspores, which
germinate into dwarf antheridial filaments,
often sessile on or near the sporanges,
which produce spermatozoids. This con-
dition is termed by Pringsheim gynandro-
sporous.

The systematic arrangement of the
species is difficult on account of the vari-
ability in the size of the filaments. Prings-
heim makes the following arrangement: —

* Spores globular.

t Sporanges opening by a valvular lid.
CE. rostellatum. Sporange oval, spore

globular, not filling the sporange.
theridia 3- or 4-celled. Monoecious.

An-

tt Sporanges opening by a lateral orifice.
\ Monoecious.

(E. curvum. Sporanges depressed, orifice
in the middle line ; spores completely
filling the sporanges, and of the same form.
Antheridia 3- and 4-celled.

(E. tumidulum. Sporange ovate, orifice
in the upper half; spore globular, not
filling the sporange. Antheridia mostly
2-celled.

}| Gynandrosporous.

(E. Rothii. Dwarf male plant straight;
sessile on the sporange, without a spreading
base. Sporange ovate, expanded in the
middle; orifice in the middle line; spores
depressed, filling the inflated part of the
sporange.

(E. depressum. Male plant straight, sessile
on the sporange, with a foot and internal
1-celled antheridia. Sporange depressed,
orifice in the middle line; spores of the
form of the sporange, not filling it.

CE. Braunii. Male plant curved, with a
foot and 1-celled antheridium. Sporange
oval, inflated in the middle ; spore globular,
not filling the sporange.

(E. echinospermum. Male plant almost
straight, sessile on the cell below the
sporange, with foot and outer 1-celled an-
theridium. Sporange oval, orifice in the
lower half; spore globular, spinous.

** Spores oval.

t Sporanges opening by a circular lid.
\ Gynandrosporous.

(E. ciliatum. Male curved, sessile on the
sporange, with foot and outer 1-celled
sporangium. Spores oval, filling the broken
portion of the sporange.

ft Sporanges opening by a latei'al orifice.
\ Gynandrosporous.

(E. apopliysatum. Male plant curved,
sessile below the sporange, and outer 2-
ranked antheridium. Sporange oval, orifice
in the upper half ; spore filling the sporange
up to the cap-like part.

J| Dioecious.

(E. gemelliparium. Male plants more
slender than the female ; antheridia many-
rowed ; pepta of the parent cells perpen-
dicular to the other cell-septa. Sporange
oval, orifice in the upper half, the spore
filling it completely to the cap-portion.
Filaments ending in several almost nyaline
elongated cells, without a terminal bristle.

BIBL. Mohl, Bot. Zeit. xiii. 689 ; De Bary,
Soc. Sc. Nat. Fribourg, 1856 ; Carter, Ann.
N. H. 3 ser. i. 29 ; Hassall, Alg. 195 ; Braun,
Kiitz. Sp. Alg. ; Eabenh. Alg. iii. 347;
Juranyi, Pringsheini's Jahrb. 1873 ; Prings-

OIDIUM.

[ 553 ]

ONCOBRYSA.

heim, Jahrb. i. 1 ; De Bary, Ann. So. N. 4
&€\\ v. 262 ; Sachs, Bot. 281.

OID'IUM, Link (Acrosporium and Sporo-
tn'c/uim, Greville ; Tontla, Corda). — A sup-
posed genus of Mucedines (Hyphomycetous
Fungi), but very probably consisting of
imperfect conditions of plants of more
complex nature. The Oidia have recently
attracted great attention on account of the
extraordinary development of the form
called Oidium Tuckeri on the vines of Eu-
rope and the Atlantic islands. This, how-
ever, like O. leucoconium and others, appears
to be only the conidiiferous mycelium of an
ERYSIPHE or some allied plant ; the parti-
culars of its history are given more at length
under VixE-FuxGUS. Oidium lactis seems
also referable to Torula, or to the myce-
lium of PENICILLIUM. O. abortifaciens,
Lk., is an imperfect state of CLAVICEPS ; O.
albicans, Robin, the fungus of APHTHA,
is probably referable to some other genus
when mature, as Achorion should perhaps
also be included under Penicillium. The
objects described as Oidia consist of delicate
horizontal filaments, creeping over leaves,
fruits, or decaying vegetable and animal
substances (O. lactis at the edges of sour
inilk, O. albicans in the mouth of the hu-
man subject), forming an interlaced fleecy
coat, the horizontal filaments giving origin
to numerous erect, usually short, articu-
lated pedicels, the uppermost cells of which
(or several of the uppermost) expand into
oval bodies (conidia) which become dis-
articulated, and, falling upon the matrix,
germinate and produce new filaments (PL 26.
figs. 8-11).

Oidium leucoconium, Tuckeri, erysiphoides
are white ; O. aureum^fidrum^fructigenum^
and others subsequently become coloured,
and these certainly belong to a different
category.

BIBL. Berk. Hook. Br. Fl. ii. pt. 2. 349 ;
Ann. N. H. i. 263, vi. 438, 2 ser. vii. 178,
xiii. 463 ; Crypt. Bot. 300, 308 ; Fries, Sum.
Vey. 494 ; Fresenius, Beitr. z. Mycol. H. i.
23, ii. 76 ; Le>eille, Ann. Sc. Nat. 3 ser. xv.
109; Grev., Crypt. _F/.pl.73; Robin, Veget.
Par. 2nd ed. 488 ; and the Bibl. of VINE-

FUNGFS.

OIKOM'ONAS, Kt.— A genus of Flagel-
late Infusoria. Exceedingly minute, ovate,
flagellum single ; a thread-like process pro-
truded at will from the posterior part of
the body, serving for attachment. Six
species; in infusions, fresh- and salt-water.
(Kent, Inf. 250).

OIL. — Oils of various kinds are most
abundantly produced by a very large num-
ber of plants, and occur to some extent in
almost all. For the microscopist, it is con-
venient to divide them into essential and
fixed oils. The former are special secre-
tions, and occur in the cells of the GLANDS
and Glandular HAIRS of the epidermis of
those parts of plants exposed to the air and
light. Fixed oils are found principally in
the cells of tissues still physiologically
active in the nutrition of the plants, and
they appear in many cases to have a close
relation with and to form substitutes for
starch. Thus fixed oils occur stored up in
the cells of the perisperms or of the cotyle-
dons of certain seeds in which little or no
starch is produced, as in the Papaveracea,
Cruciferce, Linum, the almond, nut, &c.
Oil may occur also in the pulp of fruits, as
in the olive.

SPORES of Cryptogamic plants and POL-
LEN-grains are remarkable for the oil they
exhibit in their mature condition. It ap-
pears to serve as an indifferent or inert form
of assimilated nutriment.

Oil occurs in the cavity of cells in the
form of minute drops, which may be dis-
tinguished mostly, by the experienced mi-
croscopist, by simple inspection ; but it is
often desirable to prove the nature of the
globules, which may be done by removing
them with benzole, or, in the case of pollen,
by viewing them in spirit of turpentine or
oil of lemon.

OI'THONA, Baird.— A genus of Cope-
podous Entomostraca. O. spiniferus ; marine.
(Brady, Copep., Hay Soc. i. 90.)

OLEAN'DRA, Cav.— A genus of As-
pidiese (Polypodiaceous Ferns). 6 species ;
tropical." (Hook. Syn. 302.)

OL'IGOCLASE. See ROCKS.
" OLPID'IUM, Braun.— Like Chytridium,
but without operculum or rootlet, elongated
into a cylindrical tube ; epi- or entophytic,
on freshwater Algae ; O. simulans, in the
living leaves of the dandelion. (Rabenhorst.
Alff. iii. 282.)

OMPHALOPEL'TA, Ehr.— A genus of
fossil Diatom aceae which agrees with Acti-
noptychus.

O. areolata (PI. 18. fig. 53).

BIBL. Ehr. Ber. Berl. Ak. 1844, 263;
Kiitz. Sp. Ala. 132; Grev. Mic. Tr. 1866,
122.

ONCOBRY'SA, Agardh (Hydrococcus,
Kiitz.). — A genus of Palmellaceae. Fronds
minute, hardish ; cells in rows, the super-

ONCOSPHENIA.

[ 554 ]

OOGONIUM.

ficial ones crowded, forming a cortical layer.
3 species, brownish-green or purplish ; on
submersed wood and mosses. (Rabenh.
Alg. ii. 67.)

ONCOSPHE'NIA, Ehr.— A genus of
Diatomaceae.

O. carpathica. Valves laxly striated, one
end turgid, rounded, and straight ; the other
attenuate and uncinate ; freshwater ; diam.
1-790".

BIBL. Ehr. Ber. Berl. Ak. 1845, 72;
Kiitz. Sp. Alg. 11 ; Rabenh. Alg. i. 296.

ONION, Allium Cepa (Flowering Plants,
Nat. Ord. Liliaceae). — The young bulb of the
onion offers a very good and cheap subject
for the investigation of the development of
spiral vessels, to those who do not object to
its odour ; other bulbs will do equally well.
In the cells of the base of the Ibulb occur
very elegant groups of prismatic crystals
(see RAPHIDES).

ONOCLEA, Sw.— A genus of Dick-
soniese (Polypodiaceous Ferns). Sori dorsal,
globose, on the veins of changed contracted
pinnae of the fertile fronds, and concealed by
their revolute margins. 3 species ; cold or
temperate climates. (Hook. Syn. 45.)

ONYCH'IUM, Kaulf.— A genus of
Pteridese (Polypodiaceous Ferns). Four
species ; tropical. (Hook. Syn. 143.)

ONYCHODROMUS, Stein.— A genus of
Hypotrichous Infusoria. Like Stylonichia,
but the ventral styles linear, and the caudal
setae absent. O. grandis; freshwater.
(Kent, Inf. 766.)

ONYG'E'NEL— A family of Ascomyce-
tous Fungi, containing a few inconspicuous
plants growing upon the feathers of dead
birds, or upon cast-off hoofs and horns. The
flocculent spreading mycelium usually pro-
duces on its surface little white stalk-like
bodies crowned by a globular perithecium.
At first erect and thick, these supports be-
come more slender as they elongate, and
seem to bend under the weight of the light
perithecium (fig. 531). In some species the
perithecium is sessile. The perithecium is
Silled with branching filaments, arising from
the walls of its internal cavity, interlacing
together and bearing at their free extremi-
ties globular cells (asci) containing the
spores (figs. 633, 535). At the epoch of
maturity the perithecium, originally closed,
bursts circularly to wards the base, the upper
part becoming detached under the form of
a more or less regular cap (fig. 532), expo-
sing the spores set free by a solution of the
filaments.

Fig. 531.

Fig. 532.

Fig. 533.

Fig. 534.

Onygena corvina.

Fig. 531. Plants on a feather. Nat. size.
Fig. 532. Single plant with the perithecium dehiscing.

Magn. 10 diams.
Fig. 533. Portion of the sporiferous layer, with asci.

Magn. 350 diams.

Fig. 534. Asci detached. Magn. 700 diams.
Fig. 535. Spores. Mag. 700 diams.

British Genus.

Onygena. Perithecium capitate, at length
slit round the base, and falling off' as an
imperforute cap. Asci borne at the free
ends of filaments forming an entangled mass
in the perithecium, finally free and pulvera-
ceous.

BIBL. Berk. Br. Fl. ii. pt. 2. 322 ; Ann.
N. H. vi. 432, 2nd ser. vii. 184; Tulasne,
Ann. Sc. Nat. 3 s$r. i. 367, pi. 17 ; Greville,
Crypt. Fl. pi. 343 ; Cooke, Handb. 641.

OOCAR'DIUM, Nag.,=7nomerm.

OOCYS'TIS,Nag.— A genus of Palmel-
laceous Algae, probably identical with
Nephrocytium.

BIBL. Rabenh. Fl. Eur. Alg. iii. 52.

OOGO'NIUM.— A term sometimes used
to signify the parent cell of a true female
spore.

OOLITE.

[ 555 ]

OPERCULINA.

OOLITE, or ROESTONE, is the substance
of oolitic rocks, and consists of carbonate of
lime, partly crystallized, partly granular ;
the granules usually include organic remains,
as broken shell, &c. It consists of two
parts, one of which, forming the matrix, is
mostly colourless, often crystalline, and
exhibits a number of round or oval cavities,
each of which contains a nodular granule
of a corresponding form. The nodules are
sometimes coloured, rarely hollow, and
often exhibit concentric rings like those of
calculi, and indicative of the successive
deposition of layers. Sometimes a Forami-
nifer, but more often an organic fragment, or
grain of sand, forms the nucleus of the
grain.

Polished sections of oolite form interest-
ing objects; and where the nodules are
coloured and the matrix colourless, as in
oolite from Bristol, in which the former are
red, the beauty of the appearance is in-
creased.

See ROCKS.

OOMY'CES, Berk, and Br.— A genus of
Pyrenomycetes (Ascomycetous Fungi),
founded on a minute plant growing upon
the leaves of grasses. O. carneo-albus,
(Sphceria carneo-alba, Libert) has pale,
flesh-coloured, tough receptacles 1-18" liigh,
marked with the ostioles of 3-7 perithecia
closely packed within it, bearing resemblance
to the eggs of some insects.

BIBL. Berk, and Broorne, Ann. Nat. Hist.
2 ser. vii. p. 185.

OOSPORE. — A term used to indicate a
spore which is impregnated before germina-
tion, as in (Edogonium ; and also applied to
the larger form of spore in SELAGTNELLA
and ISOETES.

OPAL. — A siliceous mineral. There are
many varieties, thin sections of which
present interesting objects for the micro-
scope and microspectroscope. Wood opal
is wood petrified with hydrated silica, and
is light and not very hard. It exhibits in
some places vegetable structure. Other
opals contain the remains of substances
which may be of vegetable origin, or of
minerals which simulate such organisms.

BIBL. Dana, Mineral. ; Slack, M. Mic.
Jn. 1873, 105 ; Zirkel, Mineral. &c. 112.
See AGATE.

OPALI'NA, Purk. and Val.— The ani-
mals comprised under this title were for-
merly regarded as Infusoria ; but later re-
searches tend to show that many are im-
perfectly developed forms or intermediate

stages of higher animals. They are micro-
scopic, oval or oblong, colourless, covered
with vibratile cilia arranged in regular rows.
Some contain a nucleus, and exhibit con-
tractile vesicles ; but they do not admit
colouring-matters, nor have they a mouth.
In one form an adhesive suctorial disk has
been observed, and in another a hook-
apparatus, probably serving the same end.
They are parasitic within the bodies, usually
the intestinal canal, of earth-worms, frogs,
Planarice, Naides, beneath the gill-plates
of Gammarus, &c.

O. (Bursaria. F.) ranarum, is figured in
PI. 31. fig. 47.

BIBL. Purkinje and Valentin, De mot.
vibr. ; Schultze, Turbell. ; Stein, Inf. ; Cla-
parede et Lachmann, Etudes, 373; Lan-
kester, Qu. M. Jn. 1870, 143; Kent, Inf. 558.

OPEG'RAPHA, Ach.— A genus of Gra-
phideae (Lichenaceous Lichens), growing on
bark of trees, stones, &c. Besides their
linear lirellee, the fronds bear spermogonia,
in O. varia and O. calcarea forming black
spots on the surface, communicating with
little unilocular cavities lined with short
linear sterigmata bearing numerous sper-
matia. Several species.

BIBL. Br. Fl. ii. pt. 1. 147; Tulasne,
Ann. Sci. Nat. 3 s6r. xvii. 207 ; Leighton,
Lick. Flora, 395.

OPERCULAREL'LA, Hmcks,= Cam-
panularia pt. (Hincks, Hyd. Zooph. 193.)

OPERCULA'RIA, Goldfuss.— A doubt-
ful genus of VorticelHna, now included in
Epistylis.

O. articulata, E. Found adherent to Hy-
drophilus piceus and Dytiscus marginalis.
PI. 32. fig. 25.

O. berberina, St. Found upon Noterus
crassicornis, a water-beetle.

Other species, on Entoinostraca, &c.

BIBL. Ehr. Infus. 286; Stein, Infus. ;
Claparede et Lachmann, Etudes, 111 ; Kent,
Inf. 710.

OPERCULI'NA, D'Orb.— ANummuline
Foraminifer. Shell flat, discoidal, many-
chambered ; spire exposed, and whorls
rapidly increasing in width. The shell-
structure of O. arabica, Carter, is described
at p. 330 (PI. 24. figs. 23-26), Rare in the
Chalk, and abundant in many Tertiary beds.
Large and plentiful in the East-Indian and
South seas; common, but small, in the
northern seas.

BIBL. Williamson, Tr. Micr. 8. ii. 159
(" Nonionina ") ; Carter, Ann. N. H. 2. x.
161, 3. viii. 311 ; Carpenter, Phil. TV. 1859;

OPHIDOMONAS.

[ 556 ]

OPHRYDIUM.

For. 247 ; Parker and Jones, Ann. N. H.
3. viii. 229.

OPHIDOM'ONAS, Ehr.— Ageneric name
applied to slender, filiform, spiral (helical),
Vibrio-like bodies, of a brown or red colour,
with obtuse ends, and actively moving
through the water by means of an anterior
flagelliform filament. Ehrenberg places
them among the Infusoria, in the family
Cryptomonadina, and admits two species,
characterized bv the difference in colour.
One was found in fresh, the other in brack-
ish water. Length about 1-570", breadth
1-9000". In some the spire forms only half
a turn, in others two and a half turns.

Probably an Alga. Is it the young state
of Spirulina ?

BIBL. Ehr. In/us. 43, and Ber. Berl. Ak.
1840; Kent, Inf. 244.

OPHI'OCLUS, Hincks.— A genus of
Hydroid Zoophytes.

Char. Stem branching, rooted by a creep-
ing stolon, capsules vnse-shaped; polypes
not retractile; body deeply constricted a
little below the base of the tentacles, which
surround a conical proboscis. Tentaculoid
organs borne on the stem and stolon, highly
extensile. Reproduction by fixed spore-
sacs.

BIBL. Hincks, Brit. Hyd. Zooph. 230.

OPHIOCY'TIUM, Nag.— A genus of
Unicellular Algae.

Char. Cells free, single, vermiculate, ob-
tuse at one end, mucronate at the other.

O. majm (PI. 5. fig. 11), on freshwater
plants.

BIBL. Rabenh. Alg. iii. 66.

OPHIO'DES, Murr.— A genus of Ixodea
(Acarina). Body thin, flat, circular ; on
foreign snakes. (Murray, EC. Ent. 203.)

OPHIO'DES, Hincks.— A genus of Hy-
droid Zoophytes. O mirabilis, on Laminaria
&c. (Hincks, Zooph. 230).

OPHIOGLOSSA'CE^E.— An Order of
Ferns, distinguished from all others by the
characters both of the vegetative and re-
productive structures. Fronds divided into
two parts, one foliaceous and sterile, the
other fertile, neither being rolled up in the
form of a crook. Sporanges destitute of
annulus, and split transversely nearly to the
base.

Ophioglossum. Sporangia sessile, in two
rows, forming a narrow spike.

Helminthostachys. Sporangia in crested
clusters, forming a long loose spike.

Botrychium. Sporangia sessile, in two
rows on the spikes which form a panicle.

OPHIOGLOS'SUM, Linn.— The typic.il
genus of Ophioglossaceous Ferns, repre-
sented by the Adder's-tongue Fern, Ophio-
f/lossum vulgatum. Other tropical species.
(Hook. Si/n. 444.)

OPHIONEL'LA, Kt.— A genus of Peri-
trichous Infusoria. Solitary, elongate,
pesistome as in VorticeUa; contained in a
soft sheath. O. picta ; freshwater. (Kent,
Inf. 734.)

OPHIOTHE'CA, Curr.— A genus of
Myxogastrous Fungi, distinguished by a
simple peridium bursting longitudinally ;
capillitium twofold, viz. hyaline articu-
lated threads, to which the 'spores are at-
tached, and echinulate thicker branched
filaments.

O. chrysosperma occurs on the inner bark
of dead trees.

BIBL. Curr. Qu. Mic. Jn. ii. 240 ; Berk.
Outl. 310 ; Cook, Handb. 402.

OPHRYDFNA, Ehr.— A doubtful family
of Infusoria, corresponding to Vorticelliiia
with a carapace.

Animals grouped in a gelatinous mass ... Ophrydium.

/"Body attached to the bottom \ T...
Animals J of the carapace by a stalk... f •"
single, j Body not \ Carapace stalked ... Cothurnia.

(. stalked. \ Carapace sessile . . . Vaginicola.

BIBL. Ehr. Infus. 291 ; Clap, et Lach.
Etudes, 93.

OPHRYD'IUM, Ehr.— A genus of Peri-
trichous Infusoria, family Vorticellina.

Char. Consists of a colourless, gelatinous,
rounded mass, either adherent or free, con-
taining numerous greenish Vorticdla-\\ke
animals imbedded and somewhat radiately
arranged within it ; freshwater. Length of
extended bodies 1-100" ; size of entire mass
from that of a pea to that of the fist, and
even more.

O. versatile (PL 31. fig. 49, portion near
the surface ; fig. 48, portion expanded by
pressure ; fig. 50, separate animal). The
gelatinous mass or envelope has been de-
scribed as consisting of separate portions or
cells, and again as forming a homogeneous
whole. It somewhat resembles and has
been mistaken for frog's spawn. The body
exhibits annular constrictions and longi-
tudinal folds, and contains scattered chloro-
phyll-granules, and a long, narrow, tortuous
nucleus. A distinct narrow elongated
O3sophagus is present. Ehrenberg remarks
that at first the individual bodies are united
in the centre by filaments, which subse-
quently disappear. The animals undergo

OPHRYOCERCINA.

[ 557 ]

ORBULINA.

the encysting process ; when they leave the
jelly, a posterior ring of cilia is formed, as
in Vorticella, and the animals swim with
the tail first.

This organism bears some resemblance to
Coccochloris among the Palmellaceae, yet it
appears decidedly animal.
O. Eichornii, on Anacharis.
BIBL. Ehr. Infus. 292 ; Stein, Inf. ; Cla-
parede et Lachmann, Etudes ; Kent, Inf. 735.
OPHRYOCERCI'NA, Ehr.- A family
of Infusoria. See TRACHELINA.

OPHRYODEN'DRON, Clap, et Lach.—
A genus of Acinetina.

Char. Acinetina with the suckers at-
tached to a long retractile proboscis.
Six species ; marine.
O. abietinum, on Campanularia.
BIBL. Clap, et Lach. Etudes, 381 j Kent,
Inf. 849.

OPHRYOGLENA, Ehr.— A genus of
Holotrichous Infusoria, of the family Bursa-
rina.

Char. Ovate ; a frontal eye-spot ; cilia in
longitudinal rows; a watch-glass-shaped
vibratile membrane near the mouth. Fresh-
water.

Five species. Stein remarks that, on
treating these animals with acetic acid, the
cilia became converted into a dense network
of curved and geniculate hairs, some as long
as the body.

O. atra (PI 31. tig. 51). Body ovate,
compressed, black, acute posteriorly ; eye-
spot black, marginal ; cilia whitish ; length
1-180".

O. acuminata, brown ; eye-spot red.
O. ftavicans, yellowish ; eye-spot red.
BIBL. Ehr. Inf. 360; Stein, Inf. 240;
Duj. Inf. 506; Lieberkiihn, Ann. N. H.
1856, xviii. 319 ; Claparede et Lachmann,
Etudes, 256 ; Kent, Inf. 532.

OPHRYOSCO'LEX, St.— A genus of
Peritrichous Infusoria. Free, ovate-elon-
gate, with a Vorticella-\ike peristome;
middle of the back surrounded by a row of
stout setae ; a long posterior style-like pro-
cess. 2 species j in the rumen and reticulum
of ruminants. (Kent, Inf. 652.)

OPISTHIOT'RICHA, Perty.— A genus
of Infusoria.

Char. Small, cylindrical or pyriform

Cilia on body fine, those on posterior part

large. O. tennis, in bog-pools.

BIBL. Perty, Lebensf. 150.

OPISTHODON, Stein.— A genus of Hy-

potrichous Infusoria. Free, ovate, dorsally

convex, vertically plane, ciliate ; mouth

near the posterior half, with a cylindrical
rod-fascicle. O. niemeccensis : freshwater.
(Kent, Inf. 749.)

OPISf HOTRICH'IA, Kt.— A genus of
Hypotrichous Infusoria. Free, ovate ;
frontal, ventral, and anal styles as in Oxy-
tricha, also with caudal setae. 2 species ;
freshwater. (Kent, Inf. 785.)

ORBICULI'NA, Lamk.— A genus of
porcellaneous Foraminifera. Discoidal, equi-
lateral, greatly compressed, very variable
according to age ; forming an embracing,
very regular spire when young, subse-
quently growing into a more or less perfect
disk, almost undistiuguishable from Orbito-
lites. Chambers very narrow, curved, and
divided throughout their length into nu-
merous minute cavities (chamberlets) by
perpendicular partitions, transverse to the
spiral coil. Orifices very numerous, round,
in rows along the septal plane on the outer
margin of the shell.

Living in tropical seas (O. adunca, PI. 23.
fig. 19) ; fossil in the Tertiaries.

BIBL. Carpenter, Phil. Tr. 1856, 547:
For. 93.

ORBITOI'DES, D'Orb.— One of the hya-
line Foraminifera, related to Nummulites
and often mistaken for it. Lenticular;
thick or thin ; smooth, granular, or radiate j
composed of a median plane of chamberlets
arranged cyclically, and of very numerous
layers of compressed chamberlets above and
below.

Fossil only ; in the Upper Chalk, and
Lower and Middle Tertiaries.

BIBX. Giinibel, Abh. bayer. Ak. 1868, x.
670.

ORBITOLI'NA. See PATELLINA and

POROSPHJERA.

ORBITOLI'TES, Lamarck (Orbulites).—
A porcellaneous Foraminifer, near Orbiculina,
but distinguished by the chambers being
arranged in concentric circles.

Inhabiting tropical seas.

O. complanatus (PI. 23. fig. 17 ) = Sorites
and Amphisorus, Ehr. j fossil in the Lias,
Chalk, and Tertiaries.

BIBL. Morris, Brit. Foss. 39 : Carpenter,
Phil. Tr. 1856, 181 ; For. 105.

ORBULI'NA, D'Orb.— A hyaline Fora-
minifer, consisting either of a single spheri-
cal chamber, or of a large globular chamber
enclosing a small Globigerine group of
earlier cells. Perforations numerous, minute
and of two sizes ; but single orifice doubtful.
O. universa(P\. 24. fig. 1). Recent, and
fossil as far back as the Lias.

ORGANIZATION.

[ 658 ]

ORIBATEA.

BIBL. D'Orbigny, For. VienS22; William-
son, Eec. For. 2; Carpenter, For. 176;
Alcock, Mem. Lit. Phil. Manch. 3. iii. 178 j
S. Owen, J. Linn. Soc. Zool. ix. 149; Ter-
quem, Mem. Metz, 1862, 432; Brady, Qu.
Mic. Jn. n. s. xix. 75.

ORGANIZATION AND VASCULA-
RIZATION. — Immediate reunion of cut
surfaces may take place without any exuda-
tion ; but in healing by what is termed the
first intention, a substance is present which
glues the edges of the wound together.
This consists of the connective tissue of the
cut surface, infiltrated with blood-corpuscles
and serum, and swollen by the imbibition
of the latter. The next stage of the pro-
cess is the migration of colourless corpuscles
from the dilated vessels in the immediate
neighbourhood. They permeate the whole
of the cementing medium and the adjacent
connective tissue, so that the divided parts
are at length united by a continuous layer
of embryonic tissue. The next step is the
reestablishment of the circulation. Thiersch
found the cut ends of the vessels a few
hours after the injury plugged by a cor-
puscular proliferation and somewhat dilated,
but seldom occupied by a blood-clot. In-
jecting the vessels at this stage with a warm
solution of gelatin, and hardening the speci-
men in alcohol, he found sticking to the
surface of the club-shaped plug of gelatin,
endothelial cells, some detached and isolated,
others undergoing proliferation. Moreover
he found a peculiar configuration of the
surface of the plug, in which were the
radicles of a very beautiful system of inter-
cellular canals, forming a provisional nu-
trient apparatus. The last act is the trans-
formation of that part of the embryonic
tissue which is not employed in the con-
struction of vessels, into fibrous connective
tissue. Should pus be formed in a wound,
healing by the second intention occurs (see
Pus). Pus is given ofi' from the wound,
and from its surface young cells force their
way from countless points ; they are accom-
panied by a fluid mainly transmitted from
the blood, and very rich in dissolved al-
buminous matters. Sooner or later the cells
close up their ranks, and a layer of em-
bryonic tissue is formed, which intervenes
between the parenchyma of the organism
on the one hand and the pus on the other.
Then this embryonal connective tissue gets
thicker, rises into small globular projections
or granulations ; they produce both skin and
cuticle, and new vessels. Along certain

lines running through the parenchyma in
which these new vessels are to be, a closer
aggregation of the cells becomes apparent;
a cord or row of cells becomes visible,
pointing out the form and direction of the
future blood-path. Soon the blood makes
its appearance in the axis of the cellular
cord, and the cells parted asunder begin to
constitute the wall of a new blood-vessel.
As each layer of embryonal tissue is formed
on the surface, rows of cells aggregate as
above, and new vessels are completed. As
the cicatrical tissue contracts after its for-
mation out of the embryonal tissue, and as
it is fashioned at the deepest part of the
wound, first the whole of the raw surface
shrinks and compresses the vessels, obliterat
ting many and reducing the vascularity of
the healing tissues.

ORIB'ATA, Latr.— A -genus of Oriba-
tidae, of which there are several species, on
stones and plants. Some are common.

The position of three species is doubtful,
viz. Acarus conferva, Schr., freshwater,
creeping upon Confervas, &c. ; Oribata de-
mersa, Duj., with a cervical eye, upon
Hypnum inundatum ; and Oribata marina,
a marine species.

BIBL. Gervais, Walck. Apt. iii. 251 ;
Schrank, Ins. Austria, 611 ; Duiardin,
rinstit. 1842, 316; Koch, Deutschl. Crust.-,
Duges, Ann. Sc. Nat. 2. stSr. ii. 46 ; Murray,
EC. JSnt. 217.

ORIBATEA.— A family of Acarina.

Char. Body covered by a hard horny
dark envelope; palpi fusiform, 5-jointed ;
first joint small, second large, inflated and
almost half the length of the entire palpus,
palpi hairy outside only ; mandibles chelate;
body often winged ; no suckers. Genera :

Nothrus. Body elongate, irregularly
quadrilateral, with spinous filaments; legs
of moderate length, thick, tarsi with 3
homodactyle claws.

Belba. Abdomen distinct from thorax,
rounded, inflated; legs long, geniculate,
with 1 claw.

Oribata. Cephalothorax with lamellar
appendages ; tarsi with 3 heterodactyle
claws ; hairs bristle-shaped.

Cepheus. Cephalothorax lamellar : claws
3, alike.

Notaspis. Cephalothorax lamellar, tectum
confounded with it.

Leiosoma. Cephalothorax with plates,
claws 3, heterodactyle.

Pelops. Like Oribata, but hairs flat and
spatula-shaped.

ORXITHOBIUS.

[ 559 ]

ORTHOTRICHUM.

Hermannia. Cephalothorax soldered to
abdomen ; tarsi with 1 claw.

Eremceus. Cephalothorax simple ; tarsi
with 3 heterodactyle claws.

Damceus. Cephalothorax ribbed, legs
longer than the body, 1 claw.

Galumna. Abdomen subglobular, de-
pressed, margins of the pseudothorax
winged ; legs of moderate length.

Hoplophora. As the last, but wing-like
appendages absent ; tarsi 1-clawed.

BIBL. Walckenaers Apteres, 251 ; Koch,
Deutschl. Crustac. ; Duges, Ann. Sc. Nat. ii.
48 ; Dufour, Ann. Sc. Nat. 1 ser. xxv. 289 j
Nicolet, Archiv d. Museum, 1855 ; Michael,
M. M. S. 1879, 225, 1880, 32, 177.

ORNITHO'BIUS, Denny.— A genus of
Anoplura. Like Nirmus, but with 2 horns
to the clypeus. O, cygni, on the swan ; 2
other species.

OROBIAS, D'Eichwald.— A Nummuline
or Fusuline Foraminifer, found in the Car-
boniferous Limestone of Russia ; possibly a
true Nummulina.

BIBL. D'Eichwald, Leth. Ross. i. 352.

ORTHOCERFNA, D'Orb.— A Sticho-
stegian Foraminifer, related to Nodosarina ;
square or triangular in cross section; without
septal furrows ; orifice terminal, simple or
pouting.

Recent in W. Indies, O. quadrilatera (PL
23. fig. 36) ; fossil in the Tertiary, Chalk,
Gault, and Oxford Clay.

BIBL. Carpenter, For. 166.

OR'THOCLASE. See ROCKS.

ORTHODON'TIUM, Schwagr.,=5n/wra,
pt. O. gracile, on sandstone rocks. (Wilson,
Bryol. Brit. 218.)

ORTHOP'TERA.— An order of Insects,
containing the grasshoppers, crickets, &c.

ORTHOSI'RA, Thw. See MELOSIRA.

ORTHOTRICHA'CE^E.— A tribe of
Pottioid Mosses including several British
genera.

a. Papillae, distinct, tuberculate, rarely obso-
lete ; peristome mostly pale, rarely orange-
coloured.

Zygodon. Calyptra dimidiate. Peristome
wanting, simple, external or internal, more
rarely glabrous, without an annulus.

Orthotrichum. Calyptra campanulate,
plaited. Peristome absent, simple, or
double. External of thirty-two geminate
(sixteen, fig. 483) or bigeminate (eight,
fig. 537) teeth, more rarely of sixteen entire,
undivided teeth, granular, fleshy or brittle,
mostly pale, rarely orange-coloured, erect,

afterwards reflexed, arising below the mouth
of the capsule. Internal : eight or sixteen
cilia, simple, hyaline, or rarely resembling
the teeth. Vaginule ochraceous. In-
florescence monoecious or dioecious. Capsule
without an annulus, pyriform, grooved,
rarely glabrous; operculum capitate, conical.

b. Papilla mostly obsolete, rarely distinct]
peristome always coloured, purple, red, or
orange.

Glyphomitrium. Calyptra campanulate,
large, totally enclosing the capsule, deeply
laciniate, plaited. Peristome of sixteen
short, lanceolate, densely trabeculate, entire
teeth, with a central line, in pairs, incurved,
arising below the orifice, orange-coloured,
smooth (fig. 283, p. 360). Inflorescence
monoecious.

Brachystelium. Calyptra as in the pre-
ceding, entirely or almost covering the cap-
sule, mitre-shaped, with long and repeated
laciniations, slightly plaited. Peristome as in
Trichostomum, the teeth more or less split
to the base into two arms. Inflorescence
monoecious.

Guembelia. Calyptra dimidiate, otherwise
like the following (figs. 289-291, p. 366).

^ Grimmia. Calyptra mitre-shaped, laci-
niate, smooth, scarcely exceeding the oper-
culum, or shorter. Peristome simple, teeth
sixteen, lanceolate, with a median line,
trabeculate ; often, however, fissile, hence
very polymorphous, more or less split as far
as the middle into two or four teeth, or into
two arms down to the base (fig. 288, p. 365).
Fig. 536. Fig. 537.

«^T»

Fig. 6bti. Orthotrichum pulchellum. Mara. 15 diams

Fig. 537. Orthotrichum pallens. Fragment of peri-

etome. Magn. 50 diams

ORTHOT'RICHUM, Hedwig._A genus
of Orthotrichaceae (Pottioid Mosses), grow-
ing in round tufts, fertile at the summit, on

OSCILLATORIA.

trees and stones, never on the earth. Bri-
tish species numerous, remarkable for the
apophyses, sometimes having stomata, and
the varied character of the outer peristome,
the thirty-two teeth of which are variously
conjoined, so as to appear thirty-two, six-
teen, or eight. Calyptra mostly covered
with hair-like processes (fig. 472, p. 512).

BIBL. Wilson, Bryol Br. 185 ; Hooker,
Br. Fl. ii. pt. 1. 57 j Venturi. M. M. Jn.
1881, 80.

OSCTLLATO'RIA, Vauch.— A genus of
Oscillatoriaceae (Confervoid Algae), distin-
guished from the allied forms by the simple,
rigid, elastic filaments, forming a stratum
in a common gelatinous matrix. Filaments
enclosed singly in tubular -cellulose sheaths,
open at the ends, from which the fragments
emerge when broken across (PL 8. fig. 8).
The young filaments or growing extremities
are continuous and scarcely striated ; but
by degrees transverse striae appear, some-
times very close together, sometimes dis-
tant, indicating a constriction and final
fission in the substance of the filament,
which, when old, readily breaks at these
places. The internal structure of the fila-
ment is obscure : it seems to be composed
wholly of protoplasmic substance, the joints
not possessing special cellulose coats; but
the substance of the filament, although
apparently solid, seems sometimes less dense
internally, since we have noticed a kind of
hour-glass contraction intermediate be-
tween the striae after the action of thick
syrup (by endosmose) and after desiccation.
The curious rounding-off of the separated
ends of dividing filaments (PL 8. fig. 8,
right-hand figures) seems to depend on some
power of expansion of an outer thicker layer
of the substance of the filament. The mo-
tion of the filaments will be described
under OSCILLATORIACE^J. The filaments
ultimately break up at the striae into di-
stinct joints, which may be regarded as
gonidia. No formation of spores has been
observed. A remarkable and unexplained
appearance is occasionally observed at the
growing ends of the filaments : they appear
crowned by a wreath of cilia ; but these
processes are rigid and motionless.

The species occur on damp ground, on
stones, mud, in fresh water, running or
stagnant, in springs, and in brackish water ;
a few are truly marine. In the following
characters the colour of the strata is given
as seen by the naked eye, that of the fila-
ments as seen under the microscope.

[ 560 ] OSCILLATORIA.

* In fresh water, or on damp earth, &c.
a. Stratum ccruginotis or blue-green.

O. limosa, Ag. Stratum dark green,
glossy, with long rays; filaments green,
1-3300 to 1-3600" in diameter; articulations
shorter than the diameter. At the bottom
of ditches and pools.

O. tennis, Ag. Stratum dark green, thin,
with short rays ; filaments pale green,
1-4200" in diameter ; articulations equalling
or half the diameter. In muddy ditches,
&c. ; at first on the bottom, finally floating.

O. muscorum, Ag. Stratum dark aerugi-
nous-green, 3 or 4' in extent, growing over
mosses in rapid streams ; filaments thickish,
pale blue-green.

O. turfosa, Cann. Stratum pale verdi-
gris-green, glaucous, 1 or 1±' in diameter,
resting on an ochraceous substratum ; fila-
ments hyaline, very slender. On floating
sods in turf-pits.

O. decorticans, Grev. Stratum smooth,
glaucous-green, membranous, peeling off in
flakes ; filaments pale bluish green, very
slender. Damp walls, pumps, &c. ; common.

b. Stratum dutt green, inclining to purple,
black, or brown.

O. nigra, Vauch. Stratum blackish
green (bluish black when dry), with long
radii; filaments pale bluish green, 1-2800
to 1-3000" in diameter ; joints equalling or
a little shorter than the diameter. Ditches
and ponds. Common.

O. autumnalis, Ag. (PL 8. fig. 8). Stra-
tum purplish or greenish black ; filaments
pale dirty bluish green, 1-4000 to 1-5000" in
diameter ; joints shorter than the diameter.
Damp ground, walls, &c. Common.

O. contexta. Carm. Stratum glossy black,
spreading three feet or more, appearing
satiny and striated to the naked eye ; fila-
ments pate green, 1-3000" in diameter; ar-
ticulations largish. On mud ; apparently
common.

O. ochracea, Grev., is probably the same
as Leptothrix ochracea.

** Marine, or in brackish water.

O. littoralis, Carm. Stratum bright aeru-
ginous-green ; filaments deep green, thicker
than in O. ni.gr a ; joints one third the
diameter. Pools on the sea-shore. See
SYMPLOCA.

BIBL. Harvey, Br. Alg. 1st ed. 161;
Mar. Alg. 228; Phyc. Brit. pis. 105, 251 ;

OSCILLATORIACEJS. [ 561 ] OSCILLATORIACE^.

Hassall, Ah/. 244, pis. 70-72 ; Kiitz. Sp. Alg.
237; Tab. Phyc. Bd. i. pis. 38-44 ; Rabenh.
Alg. ii. 95 ; Engelmann, Beweg. Bot. Zeit.
1879.

OSCILLATORIA'CE.E.— A family of
Confervoid Algae, containing organisms of
considerable diversity and not well cha-
racterized at present, owing to the obscurity
of the reproduction. The genus Oscillatoria,
with its nearest allies, is composed of
cylindrical filaments of protoplasmic sub-
stance, invested by a continuous cellulose
sheath or tubular cell-membrane. The in-
ternal (solid ?) filament gradually becomes
transversely striated as it increases in age,
and subsequently breaks across at the trans-
verse lines ; and the fragments readily
escape from the sheaths, since no cross walls
of cellulose are produced (PL 8. fig. 8). These
kinds exhibit clearly the remarkable motion
from which the family takes its name. They
are mostly found upon damp ground, form-
ing wide and irregular strata. Rivularia and
the allied genera have the joints of the fila-
ments more distinct j and the filaments are
coherent into definite fronds, on which they
stand erect or radiate from a centre (PI. 8.
figs. 13, 16). The sheaths often become
complicated, from the internal multiplica-
tion and the persistence of the cellulose
sheaths of several generations one within
another (see PETALONEMA), often gelati-
nously swollen up, and sometimes decomposed
into spiral fibrous structures (PI. 8. fig. 15 ;
see SPIRAL STRUCTURES). Some of the
remaining forms differ considerably from
the above, and are imperfectly understood.
Spirulind (PI. 7. fig. 15) has the filaments
curled spirally; and in the strange plant
Didymolidix (PI. 1. fig. 10) two spiral fila-
ments occur twined together. These last
minute forms generally occur imbedded in a
gelatinous stratum.

The structure of the Oscillatoriaceae,
judging from Oscillatoria, Mi&'ocoleus, and
Lynybya, differs importantly from that
of all other Confervoids. The filaments are
not composed of rows of cells, but, in the
earliest condition, of a cylindrical thread of
^protoplasm, coloured greyish, green, brown,
sor purple in different cases. The ends of
the growing filaments are narrower and de-
void of striae, and have no perceptible cellu-
lose sheath ; when a little older, cross striae
appear, consisting of double rows of granules
or dots, and the tubular cellulose coat is i
evident; finally the striae become distinct
lines (see PI. 8. figs. 8-22). In this stage, |

external violence will cause the filament to
break across at the strise ; and the fragments
then slide along inside the cellulose sheath,
the broken ends always assuming a rounded
form like that of the free extremities (PI. 8.
fig. 8b). When these fragments slide quite
out of the sheaths, the latter appear as con-
tinuous tubes (PI. 8. fig. 8 a), seldom with
any cross markings opposite the strife of the
internal mass. In Lynybya the division
seems to take place in a peculiar manner,
accompanied by an interstitial growth com-
parable to that of ZYGNEMA. In a well-
developed filament, every eighth stria is
strongest, the intermediate fourths rather
lighter, every second one between them
paler still, and the intermediates of these
only just marked; while in Oscillatoria the
striae seem to be gradually less definite
towards the growing apex of a filament.
The filaments appear solid as ordinarily
viewed ; but the endosmose resulting from
placing them in syrup or gum- water causes
them to contract between the stria?, or to
break up into lenticular disks. The ultimate
fate of all the filaments seems to be a sepa-
ration into disks or globular gonidia, by
breaking across at the striae.

In Microcoleus (PI. 8. fig. 9) and many
Rivularice there would appear to be a trans-
verse multiplication like that occurring oc-
casionally in NOSTOC, as the filaments are
found lying side by side in gelatinously de-
composed outer (parent) sheaths. The fila-
ments of the Rwularice are seated on a
large basal cell (PL 8. figs. 13, 16, 18), the
nature of which is not understood.

The remarkable spontaneous motion of
many Oscillatoriaceae presents a considerable
variety of conditions. In Oscillatoria and
Microcoleus the ends of the filaments emerge
from their sheaths, the young extremities
being apparently devoid of this coat ,- their
ends wave backwards and forwards, some-
what as the fore part of the bodies of cer-
tain caterpillars are waved when they stand
on their prolegs with the head reared up.
This motion probably depends upon the ir-
regular contraction of different parts of the
protoplasm. The filaments also emerge
from the tubes and break up ; and the frag-
ments then exhibit an oscillating movement
like that of a balance, together with an ad-
vance in a longitudinal direction. Lynybya
(PI. 8. fig. 10) does not appear to oscillate,
at all events when in long filaments ; Spini-
lina and other forms exhibit only a tremu-
lous oscillation ; Didymohelix probably ac-
2o

OSCILLATORIACE^E. [ 562 ] OSCILLATORTACE^.

quires its double-spiral character from the
entwining of originally distinct filaments,
Leptothrix and the allied genera are very
imperfectly known, and are only included
here from the absence of indications of closer
affinities elsewhere; very likely they are
mycelial filaments of Fungi.

These plants occur on damp ground,
rocks, or stones, and among Mosses and
other Confervas on rocks, stones, &c. in
fresh and salt water, and are allied in some
respects to the NOSTOCHACB^ ; but the
articulations of the filaments of the latter
are all perfect cells with a complete cellulose
wall, multiplying by division in the same
way as the Confervaceae.

Synopsis of British Genera.

A. Oscillatoriece. Filaments transversely
striated or moniliforiu, sometimes spi-
rally curled ; sheathed, or, in the minute
forms, without evident sheaths; exhi-
biting spontaneous oscillating or creep-
ing motion. Increased by transverse
division.

Didymohelix (PI. 1. fig. 10). Filaments
brown, very slender, continuous, curled spi-
rally and twisted together in pairs. No
evident sheaths, but a common investing

Oscilh

nttatoria (PI. 8. fig. 8). Filament?
coloured, continuous, transversely striated,
readily breaking across, with a proper cellu-
lose sheath, oscillating ; collected in strata
and imbedded in a common gelatinous
matrix.

Microcoleus (PI. 8. fig. 9). Filaments as
in OsciUatoria, but collected into bundles
in a common gelatinous dichotomously
branched tubular sheath ; filaments oscil-
lating.

Ccenocoleus. Filaments branched, annu-
lated, contained with their ramifications
within a tough, more or less permanent
sheath which bursts irregularly.

Symploca. Filaments as in Oscillatoria,
but erect and tufted, coherent at then' bases,
bristling above.

B. Lytigbyea. Filaments motionless (?),
oscillarioid, enclosed in a very distinct
sheath, tufted, or forming strata, with
or without an enveloping jelly.

Dasyglcea (PI. 8. fig. 11). Filaments un-
branched, sheathed; older sheaths broad,
cpalescent outside into an amorphous gela-
tinous stratum.

Lynybya (PI. 8. fig. 10). Filaments elon-
gated, distinctly articulated, unbranched,
with distinct convoluted cellulose tube, but
without a gelatinous matrix (motion creep-
ing ?) ; articulations very close.

Liebleinia. Filaments short, erect, tufted,
unbranched, with distinct cellulose coat,
free, without an investing jelly.

Chamcesiphon. Crenothrix.

C. Scytoneinece. Filaments distinctly arti-
culated, simple or branched, motionless^
with distinct articulations and large in-
terstitial (propagative ?) cells ; sheaths
at length softened and swollen, but with-
out a common gelatinous matrix.

Scytonema (PI. 8. fig. 19). Filaments
caespitose, or more rarely fasciculate, with
a double (lamellar) gelatinous sheath,
(mostly) closed at the apex ; branches con-
tinuous by lateral growing out of the pri-
mary filaments, with a knee-like base.

Desmonema. Filaments branched, more
or less coherent j branches of two kinds, pri-
mary branches each with a connecting cell
at the base, secondary branches without
connecting cells; annulated. See TOLY-
POTHRIX.

Aj-thronema (PI. 8. fig. 20). Filaments
distinctly articulated, simple, in short
lengths, overlapping at their ends within
the gelatinous sneath.

Petalomma (PI. 8. fig. 21). Filaments
branched, with the outer sheaths of the
single joints expanded upwards and out-
wards into funnel-shaped bodies, each partly
overlapping its successor, forming a common
obliquely laniellated and transversely barred
gelatinous cylinder.

Calothrix (PI. 8. fig. 22). Filaments very
closely articulated, tufted, with branches in
apposition for some distance, here and there
cohering laterally. Sheaths firm, often
dark-coloured.

Tolypothrix. Filaments free, radiantly
or fastigiately branched, most distinctly
articulated at the bases of the branches*;
branches continuously excurrent, not in ap-
position ; sheaths thin, hyaline.

Sirosiphon. Filaments single, double or
triple, within a distinct common sheath,
very distinctly articulated; branched by
lateral budding, the branches divergent.

Schizothrix (PL ^ 8. fig. 17). Filament. s
branched by division; sheaths laniellated,
thick, rigid,' curled, thickened below, finally
longitudinally divided.

Symphyosiphon. Filaments erect or as-

OSCILLATORIACEJ3. [ 563 ]

OTOGLENA.

ceuding, enclosed in lamellated,hard sheaths,
concreted laterally at their bases, involved
in jelly.

jRhtzonema. Sheath cellular and fur-
nished throughout its length with numerous
branched and anastomosing rootlets (?).
Filaments distinctly annulated, and inter-
rupted here and there by a connecting cell.
Branches in pairs, arising from a protrusion
of the filament.

Fischer a.

D. Rivulariea. Filaments distinctly arti-
culated, with an enlarged basal cell,
mostly attenuated above, connected into
definite or indefinite fronds ; motionless.

Schizosiphon (PI. 8. fig. 13). Basal cells
globose, filaments simple, distinctly articu-
lated, mostly attenuated towards the apex,
sheathed, sheaths connate into groups, hard,
dark-coloured, open and expanded above,
and overlapping so as to form a succession
of ochrese which have the free borders
slit up into filaments or fringes ; also dis-
playing a spiral fibrous structure in dissolu-
tion.

Physactis. Filaments whip-shaped, toru-
lose at the base, sheathed, sheaths simple,
gelatinous, collected into a globose and
solid, or subsequently a bullose-vesicu-
lar frond ; in the globose fronds the fila-
ments radiate from the centre, in the vesi-
cular fronds from the internal or lower
surface of the gelatinous matrix.

Ainactis (PI. 8. fig. 15). Filaments
branched, jointed, with thin sheaths, col-
lected into a solid pulvinate frond, concen-
trically zoned by the dichotomous branching
of the filaments. Sheaths more or less
solidified by carbonate of lime ; sometimes
exhibiting a spiral structure in dissolution.

Rwularia (PL 8. fig. 18). Filaments
with an oval basal cell succeeded by one of
cylindrical form (manubrium), the remainder
short, attenuated in diameter upwards (whip-
shaped) ; sheaths sometimes saccate below,
open (not fringed) above ; forming a slippery
gelatinous frond.

Euactis (PL 8. fig. 16). Filaments whip-
shaped, with repeated ochreate sheaths,
forming fronds in which they radiate, and by
superposition of successive generations form
concentric layers; sheaths cartilaginous,
lamellated, firmly united laterally, dilated
upwards (funnel-shaped), decomposed into
a fringe at the orifice.

Inomeria. Filaments whip-shaped, ver-
tical, parallel ; sheaths obscure, everywhere

decomposed into very slender filaments ;
forming crustaceous fronds, becoming stony.
Petronema. Densely caespitose, erect,
somewhat regularly branched; branches free,
with obtuse rounded apices, and each with
a connecting cell at the base. Filaments
annulated and growing thicker upwards.

E. Leptotricliece. Doubtful Oscillatoriace^.
Leptothrix. Filaments very slender,
neither branched, articulated, concreted,
nor sheathed.

Hypheothrix. Filaments unbranched, in-
articulate, sheathed, interwoven into a more
or less compact stratum.

Symploca. Filaments unbranched, inar-
ticulate, sheathed, concreted into branches,
conjoined at their bases; sheath a simple
hyaline membrane.

OSMIC ACID.— An oxide of the metal
osmium, obtained from platinum-ores. It
is a crystalline, volatile, poisonous substance,
soluble in water, with a powerfully irritating
odour. Its aqueous solution is used for
hardening and colouring certain animal tis-
sues black or dark blue, as fat-cells and
globules, the medulla of nerves, more slowly
the ganglion-cells, the connective-tissue cor-
puscles, Zoophytes, &c. The ordinary
strength is about 90 grains to a pint.
Small pieces of the structures should be
immersed in it, from £ hour to 24 houry,
then well-washed in distilled water, and
mounted in acetate of potash or Farrant's
compound. It is also useful for its remark-
able power of killing Infusoria, Rotatoria, &c.
so suddenly, that the cilia remain extended,
instead of being retracted and undistinguish-
able as with other reagents. (Ranvier, Hist,
teckn. ; Robin, Micr. 220 ; Frey, Mikr.}
OSMO'SIS. See ENDOSMOSB.
OSMUN'DA, Linn. — A genus of Osrnun-
daceous Ferns, represented in Britain by
Osmunda regalis ^(figs. 222, 223, p. 319), the
Royal or Flowering Fern, as it is termed, a
large and handsome plant, found in damp
situations ; not common.

OSMUNDA'CE^E.— An order of Poly-
podiaceous Ferns, characterized by the broad
imperfect annulus on the back of the spo-
ranges. Genera :

Osmunda. Sporangia on metamorphosed
pinnules.

Todea, Sporangia on unchanged pin-
nules.

OSTRACO'DA. See ENTOMOSTBACA.
OTOGLE'NA, Ehr.— A genus of Rota-
toria, of the family Hydatinsea.
2o2

OTOLITHS.

[ 564 ]

OVARY.

Char. Eyes three ; one sessile and cervi-
cal, the two others stalked and frontal;
neither jaws nor teeth present.

O. papillosa. Body campanulate, turgid,
rough with papillae; freshwater ; length
1-96".

BIBL. Ehr. Inf. 453; Pritchard, Inf. 690.

O'TOLITHS.— The crystalline or crys-
talloid particles found in the labyrinth of
the internal ear. They are enclosed in sacs,
appearing as white specks ; and are com-
posed of carbonate of lime, with an organic
basis, which is left after the action of dilute
acetic acid.

OTONYS'SUS, Kol.— A genus of Sar-
coptidse (Anoplura). O.sticlwlasius, on the
bat ; other species. (Maddox, M. Mic. Jn.
1871, 144; Murray, EC. Ent. 317.)

OTOS'TOMA, Carter.— A genus of Holo-
trichous Infusoria.

Char. Ovoid, mouth ear-shaped; anus
terminal ; nucleus long ; contractile vesicles
double. Its cysts have been discovered on
Nitella, and give exit to monadiform beings
approaching the parent shape.

O. Carteri, Bombay.

BIBL. Carter, Ann. N. H. 1866, xvii. 117;
Kent, Inf. 500.

OVA OF ANIMALS. — The germs secretad
by the ovaries. When extruded from the
body, they are generally termed eggs (Eo-GS).
See OVUM.

OVARY. — The organ in which the ova
or germs of the future offspring are formed
and temporarily contained.

The ovary consists of an outer fibrous
capsule, and a parenchyma or stroma.

Transverse section ol' a human ovary at the fifth
month of pregnancy, a, Graafian vesicle of the under,
b, of the upper surface ; c, peritoneum ; d, the tunica
albuginea; in the centre are two corpora lutea; e,
stroma of the ovary.

Tta outer coat, or tunica albuginea, is
firm, white, and intimately connected with

the subjacent stroma: it consists of inter-
lacing bundles of connective tissue with
few elastic fibres.

A layer of columnar or germ-epithelium
covers the capsule, therefore different from
that of the peritoneum, with which it is
continuous at the base of the organ. The
germ-epithelium here and there lines tube-
like inward prolongations (the ovarian
tubes).

The stroma (fi*. 538 e) is composed of
nucleated connective tissue, and in it are
imbedded the Graafian vesicles (fig. 538 a).
They vary greatly in number and size ; the
largest are generally nearest the surface, and
project more or less, so as to give it a nodu-
lar aspect. They are round closed sacs
(tig. 539J. Each possesses two coats ; the

Fig. 539.

G-raaflan vesicle of the pig. a, outer, b, inner layer
of the fibrous coat; c, membrana granulosa; d, liquid
contained in the vesicle ; e, proligerous disk ; f, ovum
with the zona pellucida, yolk, and germinal vesicle.

Magnified 10 diameters.

outer is a fibrous and vascular layer, con-
nected with the stroma by somewhat lax
areolar tissne, which consists of two layers :
the outer composed of ordinary fibrous con-
nective tissue; the inner consisting of young
connective tissue, rich in cells, usually fusi-
form, stellate, or spheroidal, and resembling
amoeboid cells. Lining this is the epithe-
lium of the follicle, which covers the whole
of the inside of the tunica propria, and
forms the membrana granulosa (fig. 539 c).
Next the surface of the ovary this is
thickened and projects in wards, "forming the
proligerous disk, e ; the epithelium is strati-
fied and columnar. The ovum is imbedded
in this proligerous disk.

The cavity of the Graafian vesicle con-
tains a liquid resembling the serum of the
blood ; and in it are found granules, nuclei,
and cells, arising from the disintegration of
the membrana granulo'sa.

When the vesicle bursts, the ovum es-

VIPOSITOR.

[ 565 ]

OVULE.

capes surrounded by the cells of the proli-
gerous disk and the adjacent part of the
epithelium ; the inner surface then becomes
wrinkled, and gives off flesh}' processes
which become yellowish, and form the cor-
pora lutea.

In those animals in which the amount of
stroma present is small in proportion to the
size of the vesicles, the ovaries have a race-
mose appearance.

In many of the lower animals the ovaries
are tubular, the ova lying closely packed
within them.

BIBL. Kb'lliker, Mik. An. ii. ; Siebold,
Vergl. An. ; Todd's Cyclop. An. ; Waldeyer,
Strieker's Hist.] Baifour, Gomp. Embryol.
1880.

OVIPOSITOR See INSECTS, p. 433.

OVULE or OV'ULUM.— The name ap-
plied to the rudiment of the seed of Flower-
ing Plants, produced in the ovary or ger-
men during the development of the flower,
fertilized by the pollen-grains when com-
plete ; and afterwards converted into a SEED
by the development of the EMBRYO and
other secondary structures during the con-
version of the ovary into the fruit. For the
general conditions of the ovules in ovaries,
reference must be made to botanical works.
The ovules make their appearance upon the
placenta as cellular papillae rising up from
its surface, and are at first simple ; this first
development, the main feature of the organ,
is called the nucleus (figs. 540-542). In

Fig. 540.

Fig. 541.

Atropous ovules.
Fig. 540. Young ovule of Chelidonium. «, nucleus;

ch, chalaza.
Fig. 541. Young ovule of mistletoe, consisting of a

nucleus only.

rare cases this remains naked ; but in most
instances one or two coats are produced,
arising as circular folds near the base, and
gradually growing up over the nucleus
(fig. 542), leaving only a small hole or pas-
sage at the apex, leading down to the point
of the nucleus. When two coats are
formed (fig. 543), the inner appears first;
the outer originates later and grows up over

the inner, and it is generally thicker and
more developed. The inner is the secundine
of Mirbel, the outer the primine (figs. 543,
544, 547, S, P). German writers reverse

. 543.

End

- P

Atropous ovules.

Fig. 542. Young ovule of walnut, consisting of a nucleus
2f, with a single coat S ; End, the endostome
or micropyle.

Fig. 543. Young ovule of Pplygonum. F, funiculus;
P, primine (of Mirbel) ; S, secundine; Ex,
exostome ; End, endostome.
Magnified 40 diameters.

these names, resting on the true order of
development. Some term them the integu-
mentum, internum and externum. The inner
is the tegmen, the outer the testa of Brown.
The passage at the apex, leading to the nu-
cleus, is called the micropyle ; sometimes the
orifice in the outer coat is distinguished
from that in the inner coat, and they are
termed respectively exostome and endostome
(fig. 547). While the nucleus and coats
are becoming perfected, one of the cells
situated near the apex of the nucleus takes

Fig. 544.

^^-

Sections of atropous ovule of Polygonum.

P, primine ; S, secundine ; N, nucleus ; SE, embryo-
sac : V.e, PI, nascent embryo.

Magnified 20 diameters.

on a peculiar character, becoming more de-
veloped than the rest, and often causing the
absorption of part, or sometimes the whole,
of the tissue of the nucleus ; it appears at
length as a large sac occupying the centre of
the ovule j this is the embryo-sac (fig. 544).
The base of the ovule is pushed up from
the surface of the placenta during its deve-
lopment so as to appear at length sup-
ported on a stalk of variable length ; this is

OVULE. [ 5'

termed the funiculus (figs. 543 F, 647/) ;
the point of attachment of this stalk to the
body of the ovule (marked by a scar when
the ripe seed separates) is called the hilum.
That region of the interior where the lower
parts of the coat are confluent with the
base of the nucleus, is called the chalaza
(fig. 546 C).

The form of ovules is much anected by
excessive development of their constituent
parts in special directions before the fertili-

Fig. 546.

Section of campylotropous ovule of the wallflower.

C, chalaza; N, nucleus; Dinner coat; P, outer coat.

Magnified 20 diameters.

zation. If all parts grow equally, the com-
plete ovule is erect on the placenta, with its
hilum and also the chalaza turned towards
the latter, and its micropyle at the opposite
free end : such an ovule is technically termed
atropous or orthotropous (figs. 541-545).
Very frequently an excessive growth takes
place at one side of the coats of the ovule,
so that the chalaza is carried up and di-
rected away from the placenta, the micro-
pyle being at the same time turned down
towards the latter ; but as the growth is in
the coats of the ovule, the hilum remains at
the base, near where the micropyle arrives ;
such an ovule is termed anatropous (fig. 116,
p. 157). The hilum is then connected with
the chalaza by a ridge (a kind of adherent
funiculus) called the raphe. In other cases
the form becomes altered by the point of
the ovule turning down, the entire structure
becoming folded or bent upon itself, with-
out disturbance of the relative positions of
the hilum and chalaza, while the micropyle
is brought down, as in the anatropous
ovule, to the vicinity of the hilum. This
form is termed campylotropous (fig. 546).
Other conditions occur less frequently,
among which is the amphitropous form
(figs. 550 & 551).

During these developments the embryo-
sac also undergoes various changes. Some-
times, as in the OrchidacesB, it expands so

] OVULE.

as to obliterate all the tissue of the nucleus,
and appears like a simple sac enclosed by

Fig. 548.

Fig. 549.

Magnified 40 diameters.

Fig. 550. Fig. 551.

Magnified 20 diameters.

Amphitropous ovule of mallow in different stages.
Fig. 551. Section.

the coats; in the Scrophulariaceae and other
orders it produces peculiar lobes or pouches
at various points ; in the Santalacese it grows
out from the summit of the nucleus as a
free, naked, tubular process, &c.

Up to this point the differences in ovules
are such as may be termed secondary ; but
a primary distinction now comes into view,
connected also with a difference in the ex-
ternal conditions, affording grounds for the
division of the Flowering Plants into two
great classes. In the Coniferse and Cyca-
dacese the ovules are developed upon open
carpels, and consequently the micropyle
may receive the pollen-grains immediately,
when expelled from the anthers. Plants
exhibiting this condition are termed GYM-
NOSPEBMS, or naked-seeded. In the Dico-
tyledons and Monocotyledons the carpels
are always closed up into cases or ovaries,
surmounted by a stigma, sessile or elevated

OVULE.

[ 567 ]

OVULE.

upon a style, and the pollen, falling upon
the stigma, produces there its pollen-tubes,
which pass down through what is called
the conducting tissue of the style and upper
part of the ovary, on to the placentae,
whence they make their way to the micro-
pyles of the ovules. Plants exhibiting
these conditions are distinguished as ANGT-
OSPERMS or covered-seeded.

The next phenomena which characterize
the development of the ovules of the An-
giosperms may be briefly given as follows.
The formation of the embryo-sac has already
been described. Shortly before the opening
of the flower, in most cases, this sac is more
or less densely filled with granular proto-
plasm, in which a variable number of nuclei
may be seen (PI. 47. figs. 1-7). About the
time when the pollen-grains are discharged
from the anthers, a number of minute, free,
globular protoplasmic bodies may be dis-
covered in the embryo-sac, usually three
(more rarely one) of these being crowded
into the upper end of the embryo-sac and
constituting what are called the germinal
bodies or masses (PI. 47. fig. 4). Others,
which often occur in the embryo-sac, are
generally collected near the bottom of it;
they are apparently characteristic of par-
ticular families only; in some plants they
are very large, as in the Croats. About
this time the embryo- sac often exhibits
asymmetrical growth, forming pouches or
processes, sometimes at the summit, some-
times at the base.

When the pollen-grains fall upon the
stigma, they protrude their pollen-tubes
(see POLLEN), which pass down through
the conducting tissue, and enter the micro-
pyles of the ovules. When they reach the
apex of the embryo-sac, they either stop,
often swelling a little, or they pass down a
short way over its side (PI. 47. fig. 5) ; very
rarely two pollen-tubes are found engaged
in the micropyle of the same ovule. It is
not absolutely known whether the cavities
of the pollen-tube and the embryo-sac
become actually continuous by absorption
of the walls at the point of attachment ; it
is generally believed not, but we feel some
doubt on this point. The essential point of
the process is the intermixture of the con-
tents of the pollen-tube with the substance
of the germinal body. In the higher
Crypto^amia and in the Algse, the impreg-
nation is of a similar nature ; but there the
germ-masses are fertilized by the agency of
spermatozoids, which make their way to

them, either constituting or carrying the
impregnating matter, which in the case of
the pollen-tube is a liquid, containing fine
granules, but exhibiting no trace of active
spermatic bodies, except that refractive gra-
nules are sometimes seen in active motion
in the end of the pollen-tube.

Soon after the pollen-tube has reached
the point of the embryo-sac, one (rarely
two, giving rise to POLYEMBRYONY) of the
germinal bodies becomes invested by a cel-
lulose membrane (germ-cell}, and usually
changes from a spherical to an oval form, a
transverse septum soon dividing it into two.
Most frequently the elongation continues,
with a successive formation of septa, until
the nascent embryo appears as a rounded or
oval cellule suspended at the base of a
simple confervoid filament (suspensor) ; in
other cases the formation of the first trans-
verse septum is followed by the expansion
into two globular cellules connected by a
narrow neck, the upper, almost devoid of
contents, constituting the suspensor (Pota-
mogeton, Zannichellid) ; in Orchis, the upper
of the first two cells grows upwards and
outwards, as a blind septate confervoid fila-
ment, through and beyond the micropyle of
the ovule. In Tropceolum and Zea the sus-
pensor becomes more complex, by formation
of perpendicular septa. In all cases the
end or embryonal cell, at the point of the
suspensor, which always appears densely
filled with protoplasm, ultimately enlarges,
and by segmentation is converted into the
embryo (PI. 47. fig. 6).

During the early development of the em-
bryo, the embryo-sac is often found more
or less densely rilled with free cells formed
from its protoplasm (endosperm-cells) . These
are frequently absorbed, and disappear du-
ring the growth of the embryo, this ulti-
mately filling the embryo-sac ; while in
other cases they persist and multiply, form-
ing the ALBUMEN of the seed. In the
Nymphaeaceae these cells remain, forming
an inner Endosperm or Albumen, in addi-
tion to that formed from the body of the
nucleus. In other cases (those of exalbu-
minous seeds) the embryo not only displaces
these internal endosperm-cells, but in the
course of its growth causes the absorption
of the tissue of the nucleus, and ultimately
constitutes the entire seed, enclosed only
by the true integuments. The remaining
characters are given under ALBUMEN and
EMBRYO.
Tulasne is in doubt whether the germinal

OVULE.

[ 568 ]

OVULE.

vesicles exist before the pollen-tube enters
the inicropyle. We have certainly seen
them before; but we believe they do not
possess a cellular coat before impregnation.
Observations on the ovule of Santalum
album have led us to conclude that they
receive the influence of the pollen while in
the state of nucleated protoplasmic cor-
puscles, analogous to the unimpregnated
spores of Fucus; and this view has since
been supported by the later observations of
Schacht, although Hofmeister and Radlko-
fer maintain that the germinal bodies possess
a cell-membrane before impregnation.

In the Gymnospermous Flowering Plants
(Conifene, &c.) the ovule, consisting of a
cellular nucleus and a single coat, is placed
upon an open carpel, and its widely-open
inicropyle receives the pollen-grain. At
the period of impregnation, the embryo-sac
is a cavity deeply seated in the tissue of
the nucleus ; it is formed by the coalescence
and expansion of several cells (in the Yew
there are often at first three embryo-sacs).
In the embryo-sac a number of free nuclei
soon appear, and numerous free (endo-
sperm-) cells are formed. In many of the
Abietinese this goes on until the spring
following the impregnation. Ultimately
the embryo-sac is found to have increased
to more than twenty times its original size,
with the endosperm-cells applied in layers
over the inside of its walls, increasing in
number until the cavity is filled up. Then
a certain number of cells (from three to
eight in different genera), situated near the
inicropyle end, but each in the layer next
but one to the wall of the embryo-sac,
become enlarged, and the cells intervening
between these enlarged ones (secondary
embryo-sacs) and the wall of the original
embryo-sac become divided, by two per-
pendicular septa standing at right angles,
into four cells. A central intercellular pas-
sage then appears at the contiguous angles
of these four cells. These new bodies, which
closely resemble the archegonia of the LY-
copODiACE-s:, were called corpuscula by
Brown, who discovered them.

Free cells, or perhaps merely protoplasmic
masses, are next formed in the secondary
embryo-sacs of the corpuscula, several at
the upper, one at the lower end. The pol-
len-tubes now advance, breaking down the
tissue of the nucleus, until their points
reach the corpuscula ; and one then makes
its way down the intercellular canal of
each, to reach its secondary embryo-sac;

the free cell at the base of this (germinal
vesicle) then becomes divided into four col-
lateral cells ; these multiply again ; and sub-
sequently the cellular body (proembryo) so
formed breaks through the base of the
secondary embryo-sac, and grows down in
the substance of the lower part of the nu-
cleus, which is now in a state of semisolu-
tion. The proembryo then separates into
four cords, corresponding to its four primary
cells ; and these filaments (suspensors) ter-
minate in rounded cells, each of which is
an embryonal cell; so that there are now
four times as many rudimentary embryos
as there are corpuscula. Out of all these,
only one ultimately remains and becomes
perfectly developed j the rest are absorbed
during the ripening of the seed. In the
latter, the perfect embryo is found lying in
a mass of albumen formed of the nucleus ;
its radicle, developed at the point of junc-
tion of the suspensor, never becomes very
clearly defined at its extremity, but remains
organically continuous with the albumen.

Other points relating to the development
of ovules will be found under POLYEM-
BRYONY, SEEDS, and CELL-forrnation.

The methods of investigating the deve-
lopment of ovules are simple in their nature,
but rather difficult in practice. The ordinary
plan is to place an ovule between the thumb
and fore finger of the left hand, and with a
very sharp lancet cut it into two unequal
pieces, in the direction of the axis. The
larger of the two being then laid on its flat
side on the finger (by the aid of a mounted
needle), another slice is made so as to leave
a section preserving all the central part of
the ovule. This adheres either to the finger
or the lancet ; and a drop of water should be
placed on it to free it ; then it may be trans-
ferred to a slide with a very fine caruel's-
hair pencil. Examined under a low power
(a half-inch), it will probably be found to
require further dissection, with exceedingly
fine needles, under a simple lens; some-
times mere pressure is of service. For the
minute details, the quarter and eighth ob-
ject-glasses will require to be applied. We
have found ovules which have been kept in
spirit easier to dissect ; when fresh, the cell-
membranes are excessively delicate. It need
scarcely be added that ovules require to be
examined in all stages in order to under-
stand their developmental characters; and
the student must not be disheartened by the
failure of a large proportion of his sections
to afford satisfactory observations.

OVULITES.

569 ]

OVUM.

BIBL. Brown, App. to King's Voyage,
18-2(5; Linn. Tr. 1833; Mirbel and Spach,
Ann. Sc. Nat. 2 ser. xx. 257 ; Mohl, Bot.
Zeit. 1847, 1855; Miiller, ibid. 1847;
Schleiden, Nova Actat xix. 29; Grundz.
Bot. ; Hofmeister, Entsteh. d. Embryo,
1849 ; Unters. holier. Crypt. 1851 ; Abh.
K. sacks. Ges. vi. ; Hanstein, Flora, 1857 ;
Tulasne, Ann. Sc. Nat. 3. xii. 21, 4. iv. 65 ;
Schacht, Beitr. z. An. u. Phys. 1854;
Jahrb. loiss. Bot. i. 1857 ; Bot. Zeit. 1858 ;
Criiger, Bot. Zeit. 1851, 1856; Radlkofer,
Entsteh. des Embryo, 1856; Henfrey, Linn.
Tr. xxi. 7, xxii. 69; Tr. Brit. Asaoc. 1856;
Bentley, Man. Bot. ; Henfrey-Masters, Bot. ;
Chatin, Ann. Sc. N. xix. 1874, 1 ; Sachs, Bot.
558; Strassburger, Zelleribildung , 1880.

OVULITES, Lamarck (Oveolties) .— A
large elegant one-celled Foraminii'er, re-
garded by some as a calcareous Alga ; either
ovoid, sausage-shaped, or like a drumstick ;
shell porous, with, large terminal apertures ;
length 1-25" and more.

Fossil; abundant in the Eocene of Grig-
non, Hauteville, &c., France; rare in the
Miocene of San Domingo.

BIBL. Parker & Jones, Ann. N. H. 3. v.
292, and 1877, xx. 77.

OVUM or ANIMALS. — Several points in
regard to the structure of the ovum, and
the nature of the changes which it under-
goes at different periods of its development,
are in doubt and obscurity.

The first perceptible trace of the ovum
existing within the ovary is formed by a
very minute granule or globule, not sur-
rounded by a cell-wall. This gradually
enlarges; and when it has attained a certain
size, being still very minute, a smaller sphe-
rical globule forms in its interior. The
minute internal globule is t\\Q germinal spot ;
and the external globule is the germinal
vesicle. It appears, however, that in some
cases the germinal spot is formed first, and
the germinal vesicle subsequently. When
these have still further grown, a cell-wall
separated by a slight interspace forms
around the germinal vesicle ; and this inter-
space contains a transparent liquid. Minute
granules then arise in the liquid, which
becomes inspissated; and subsequently a
number of globules of sarcode — yolk-
globules — become perceptible in it ; this
mass forms the yolk ; and the surrounding
membrane is the vitelline membrane. As
the ovum attains further development, al-
buminous layers are deposited upon and
fused with the vitelline membrane, forming

the zona pellucida or chorion (fig. 552 rt),
Fiff. 552.

Human ovum from a Graafian vesicle of moderate
size, a, zona pellucida; b, vitelline membrane and
outer boundary of the yolk ; c, germinal vesicle with
the germinal spot.

Magnified 250 diameters.

which appears as a w^hite ring. The yolk-
globules are sometimes transparent, or
slightly granular; at others they contain
one or several vacuoles, and are frequently
aggregated into little groups. The yolk,
as it approaches maturity, frequently be-
comes coloured. It is usually whitish or
pale yellow in the Mammalia, Reptiles, and
Fishes, bright yellow or reddish in many
Birds, and often green, blue, violet, or red
in the Invertebrata. In the yolk of the
ova of reptiles and fishes, crystalline plates
are met with, consisting of an albuminous
substance, allied to Haematoidine.

Viewing the ovum as a simple cell, the
germinal spot represents the nucleolus. the
germinal vesicle the nucleus, the vitelline
membrane or zona pellucida the cell-wall,
and the yolk the cell-contents.

Some authors consider that the vitelline
membrane is formed after the chorion.

The ovum of man and the mammalia
differs from that of the lower animals in its
remarkably small size, which depends upon
the extremely small quantity of yolk enter-
ing into its composition. The mature ovum
of man and mammalia averages about 1-200
to 1-150" in diameter, being rarely 1-100".
Another peculiarity consists in their ova,
instead of being in immediate contact by
means of their chorion or outer envelope
with the stroma of the ovary, or loose
within the cavity of the latter, AS in other
animals, being enclosed in distinct larger
cells — the Graafian vesicles.

On the escape of the ovum from the ovary,
the phenomena which ensue vary according
to whether the ovum has been impregnated
or not. In both cases the germinal vesicle
and spot disappear; an interspace, filled
with albuminous liquid, occurs between the
yolk and the zona pellucida ; the ovum

OVUM.

[ 670 ]

OVUM,

becomes covered with cilia, and undergoes
a regular motion of rotation; and certain
movements and changes in form of the
yolk-substance, which forms Amoeba-like
processes, have been noticed. In the un-
impregnated ovum, decay and decomposi-
tion subsequently take place.

The essential part of the process of im-
pregnation consists in the penetration of
the yolk by the spermatozoa, and their
subsequent solution in it. This takes place
either through the micropyles or the radiate
canals, or directly into the naked yolk.

In the impregnated ovum, the germinal
vesicle soon disappears, the chorion becomes
thinner, the ovum grows, and the yolk be-
gins to undergo segmentation ; but just
before this process commences, one or two
globules separate from the substance of the
yolk, being apparently pressed out of it,
and occupy the interspace between the yolk
and the chorion; these globules subse-
quently dissolve in the liquid.

In the process of segmentation, at first a
notch or slight indentation appears on some
part of the surface of the yolk; this be-
comes deeper and deeper, so as to encircle
the yolk with an annular depression. Soon
after the commencement of this, a clear
spot appears in the centre of each circum-
scribed portion of the yolk. The depression
becoming deeper, the yolk is divided into
two distinct portions. The process is con-
tinued in the case of each of these in
exactly the same manner, and in that of
the segments arising from their subdivision
also, each simultaneously acquiring a clear
spot, until the yolk appears entirely com-
posed of innumerable small bodies having
the appearance of nucleated cells. Finally
these become very minute, and the yolk
acquires much the appearance it had before
impregnation. Cells then form in the yolk,
as in an ordinary blastema, from without
inwards, and from the spot originally occu-
pied by the germinal vesicle as a centre ;
and from these the tissues of the embryo
are formed.

According to this description, the seg-
mentation is not a process of cell-division
or endogenous cell-formation, and the nu-
clear spots would correspond to portions of
the yolk substance from which the granules
and globules of sarcode were absent. Com-
pare p. 140.

In unimpregnated ova, segmentation takes
place to a certain extent, but irregularly and
incompletely.

In the impregnated ova of some animals,
as in certain of the Batrachia, most fishes
and Cephalopods, the segmentation is only
partial, a portion of the yolk remaining as
at first.

In some of the Mammalia, the zona pel-
lucida is traversed by very fine radiating
lines (canals), which are best seen in ova
immersed in water.

In the lower Vertebrate animals, the ova
are often covered by new layers, secreted
by the ovaries, as in the Batrachia (frog,
&c.), where a thick gelatinous coat is pre-
sent. In the osseous Fishes, the vitelline
membrane is frequently elegantly sculp-
tured, and finely and closely punctate from
the existence of minute canals traversing
its substance. A second coat is also pre-
sent, and sometimes a third or albuminous
layer. In many of the Cyprinoidea, this
layer is represented by small radiate cylin-
ders. In several Fishes, as is so general
amongst the Invertebrata, especially Insects
(Eoos), the vitelHne membrane or chorion
exhibits a facetted or sculptured appearance,
derived from the impression of the epithe-
lium lining the ovarian passages.

In addition to the fine canals traversing
the membranes of the ovum, one or more
large canals or apertures are frequently met
with resembling the micropyles of vegetable
ovules, and receiving the same names; these
are most distinct in the ova of fishes and
insects.

The study of ova and their changes is
very difficult. The most favourable objects
for the purpose exist perhaps in those of the
aquatic Mollusca ; the ova of insects, as the
large species of Musca, of species of Pule.r,
&c. are also easily accessible. Some im-
portant results have been obtained with the
ova of the frog (frog's spawn).

BIBL. Kolliker, Mik. An. ii. ; Thomson,
Cycl. An. art. Ovum ; Newport, Phil. Tr.
1861 and 1853; Siebold, VergLAn.; Meiss-
ner, Sieb. $ Kottik. Zeitsch. vii. 208, 272 ;
Leuckart, Mull. Archiv, 1855 ; Claparede,
Bibl. Univ. Gentve, 1855; Ann. N. H.
1856, xvii. ; BischoiF, Sieb. $ Koll. Zeit. vi.
377; Radlkofer, Befruchtungs. 1857; Bene-
den & Bessels, M. M. J. 1869, 41 ; Kupffer,
M. Mic. Jn. 1869, 47 ; Kowalevski, Mem.
St. Petersb. xvi. 1871 ; Klein, M. M. J. vii.
1872, 193 ; Beale, Tr. Mic. Soc. 1867; How
Sfc. 307; Beneden, FCEuf, 1870; Dallinger
& Drysdale, M. M. Jn. xviii. 86 ; Schafer,
P)-. Roy. Soc. no. 168 ; Kolliker, Entwickel;
Balfour, Comp. Embryol. j M. Baker, Phys.

OVUM.

[ 571 ]

PACHYGNATHUS.

1880; His,Menschl.Emb)yo,lS80; Reichert,
Menschl. Frucht. 1873 ; Girdwoyn, Mai d.
CEufs (fish), 1880.

OVUM OF PLANTS. See OVULE.

OXALATES. See the bases.

OXYR'RHIS, Duj.— A genus of Flagel-
late Infusoria, belonging to the family
Thecamonadina.

Char. Body ovoid - oblong, rugose, ob-
liquely notched in front and prolonged into
a point ; several flagelliform filaments (two,
Kent) arising laterally from the bottom of
the notch.

O. marina (PI. 31. fig. 54). Body colour-
less, subcylindrical, rounded behind; ma-
rine ; length 1-500".

BIBL. Dujard./n/. 347; Pritchard, Inf. 513.

OXYT'RICHA, Bory, Ehr.— A genus of
Hypotrichous Infusoria, of the family Oxy-
trichina.

Char. Closely resembling Stylonychia ;
but the front of the body not produced.

O. pellionella, E. (PI. 31. fig. 52). Body

whitish, smooth, slightly depressed, equally
rounded at the ends, often somewhat broader
in the middle ; head not distinct ; mouth
ciliated; tail with bristles. Freshwater:
length 1-720 to 1-280".

O. ffibba E. (PI. 31. fig. 53). Body white,
lanceolate, obtuse at each end, ventricose
in the middle ; ventral surface flat, with a
double row of setae ; mouth large, rounded.
Freshwater; length 1-240". Other species.

According to Haime7 Oxytricha is the
larva of Aspidisca.

BIBL. Ehr. Inf. 363; Duj. Inf. 416;
Haime, Ann. Sc. Nat. 3. xix. 109 ; Clap, et

family of Hypo-

Lachm. Etudes, 139 ; Kent, Inf. 786.

OXYTRICHI'NA.— A family of ]
trichous Infusoria.

Char. Carapace absent; body depressed,
with vibratile cilia, setse, or cirri, and non-
vibratile styles or hooks. Movement crawl-
ing. Alimentary orifices two, neither ter-
minal.

Genera : —

if

Tvrov^-Tioi ™™
Marginal cirri

l\

I!

/
s, j

... )
(

The anterior part of the body not pro-
longed as a neck, furnished with cirri Oxytricha.

The anterior part of the body neck-like,
and cove red with cirri Stichochceta.

No marginal cirri

/Foot-cirri in regular rows
J longitudinal or oblique

(.Foot-cirri not arranged in rows , Stylonychia.

fw,-f>, ft.™toi f Foot-hooks / No dorsal bristles Euplotes.

J oirn 1 exist i Dorsal bristles Schizopus.

•*) Cim [No foot-hooks Campylopus.

^Without frontal cirri Aspidisca.

BIBL. Ehr. Inf. 362 ; Pritch. Inf. 639 ;
Clap, et Lachm. Etudes, 168.

OXYUR'IS, Rud. See ASCARIS.

OY'STER (Ostrea).— A genus of Lamel-
libranchiate Mollusca.

The gills of O. edulis, the common oyster,
show the ciliary movement ; but it is not so
easily seen in this as in the marine mussel.

The shells of the fry or 'embryo oysters'
exhibit the black cross and an imperfect
set of coloured rings with polarized light.

P.

PACHNOC'YBE, Berk.— A genus of

• • /TT 1 J. T1 *\

have an erect filiform stem, composed of
conjoined filaments, capitulate above, the
head being; pruinose (not fiocculent), with
crowded simple spores. The pedicels are
mostly brownish or blackish, the spores
light-coloured ; the entire plants from 1-24
to 1-6" high. Several species occur on
rotten wood, stems, &c.

BIBL. Berk. Hook. Br. Fl. ii. pt. 2. 333;

Ann. N. H. 2. v. 465; Fries, Sum. Veq.
467.

PACHYG'NATHUS, Duges,— A genus
of Trombidina (Acarina).

Char. Palpi conical, last joint scarcely
forming a claw; mandibles stout, chelate;
body entire, narrowed in front ; coxae dis-
tant ; legs gressorial, sixth joint very long,
seventh very short; anterior legs longest
and stoutest.

> P. velutinus (PL 6. fig. 34), the only spe-
cies. Found in autumn, under damp stones.
Hairs covering the body short, flat, and
curved, giving it a velvety aspect. Body
inflated, narrowed in front, the narrowed
portion with two projecting brownish eyes.
Insertions of the legs in two groups, not
far distant, or from the median line ; second
pair of legs shortest ; in all the sixth joint
very long, the seventh very short and nar-
row (6), as in Tetranychus, Megamerus, and
Raphiynathus ; claws two, large ; rostrum
projecting; palpi (a) short, about twice the
length of the labium ; mandibles very large
and stout at the base. Movement slow.

BIBL. Duges, Ann. Sc. Nat. 2. ii. 54;
Gervais, Walck. Aptfrr. iii. 171.

PACHYMA.

[ 572 ]

PADINA.

PACHY'MA, Fr. — A supposed genus
of Sclerotiacei, but probably a condition of
certain roots, the substance being converted
into pectic acid. It is well known in the
United States under the name of Tucha-
hoo.

BIBL. Fr. Syst. Myc. ii. 242 ; Berk. Int.
Crypt. Bot. 254.

PACHYMATIS'MA, Bowk.— A genus
of marine Sponges.

Distinguished by the fleshy, crust-like,
not cellular nor elastic mass, covered by a
thick skin, and perforated by scattered ori-
fices ; the interior beset with siliceous aci-
cular and stellate spicula. P. Johnstonia.
(BoAverbank, Brit. Sponq., Ray Soc.)

PACHYPHLCE'US, Tul.— A genus of
Tuberacei (Ascomycetous Fungi), with a
common warty integument opening by a
terminal aperture with a distinct base, cla-
vate asci, and spherical s-poridia. Three
species occur in Great Britain.

BIBL. Tul. Fung. Hyp. 130 ; Berk, and
Br. Ann. N. It. xiii. 359, xviii. 79 j Berk.
Outl. 377 ; Cooke, Handb. 743.

PACHYT'ROCHA, Kent.— A genus of
Peritrichous Infusoria. Like Cothurnia,
but with a fleshy pad closing the carapace.
P. cothurnoides ; pond-water. (Kent. Inf.
729.)

PACINIAN CORPUSCLES. — These
curious organs form terminations or appen-
dages of the spinal nerves in the skin and
subcutaneous tissue of the palm of the
hand, the sole of the foot, the fingers and
toes, in the sympathetic semilunar ganglia,
the mesentery, &c.

They are elliptical or pear-shaped, whitish,
and about 1-25 to 1-6" in diameter. Each
consists of from twenty to sixty concentric
layers of connective tissue (fig. 553), sepa-
rated by interspaces, those between the
outer layers being considerable, those be-
tween the inner being small ; each is lined
with epithelium. They surround a cavity
filled with soft, abundantly nucleated and
very easily alterable material, which under-
goes coagulation after death, and into the
interior of which the nerve-fibres penetrate.
They are filled with a clear serous liquid ;
each is also furnished with a stalk, contain-
ing a slender nerve-fibre, which passes into
the central space, in which it terminates,
frequently in two or three branches, each
with a granular tubercle.

The Pacinian corpuscles are met with
also on the nerves of many Mammalia, and
are very numerous in the skin, the beak,

Fig. 553.

A human Pacinian corpuscle, a. Btalk ; b nerve-fi
within it ; c, outer, d, inner layers of the sheath ; e, p
nerve-flbre in the central cavity ; /, its termination.

fibre
pale

Magnified 350 diameters.

and the tongue of birds. They are readily
examined in the mesentery of the cat

BIBI, KolKker, Mik. An. ii. ; Schultze,
Strieker's Hist.

PADI'NA, Adanson.— A genus of Dic-
tyotacese (Fucoid Algse), containing one
species, P. Pavonia (fig. 554), found rarely
in summer and autumn on the south coast
of England. The fan-shaped or reniform
fronds grow in tufts, and are 2 to 5" hio-h
sometimes entire, sometimes cleft (fig. 554)'
They are marked with concentric zones'.
The substance is parenchymatous — the
number of layers of cells diminishing, with
the thickness and solidity, from the base to
the edges. The back of the frond is covered

PADINA.

[ 573 ]

PALMELLA.

by a layer of cells much smaller than the
rest, forming a kind of epidermis, which
ultimately acquires a tluckish cuticular

Fig. 554.

Padina i'avonia.
Frond, one third natural size.

layer. The growing edge of the frond is
rolled backwards (circinate) and fringed.
The fructification occurs in linear concentric
sori, on the coloured zones of the frond.
The pear-shaped spore-sacs (tig. 555) origi-
nate from cells of the epidermal layer, which

Fig. 555.

Vertical section of a frond at a concentric ZOIK-, inr.de
in a radial direction, cutting through the sorus of spore-
sacs and a line of hairs. The indusial layer of cuticle
has been removed.

Magnified 50 diameters.

take on special development, and in the
course of their growth push up and finally
burst through the loosened cuticular layer
which originally clothed them, so that the
latter forms a kind of indusium like that of
the Ferns. The spore-sacs produce each
four spores, which separate after their escape
from the sac. The zones of the sori alter-
nate with zones composed of tufts of jointed
hairs placed in corresponding lines (fig. 555).
Thuret states that he has never found
antheridia hitherto, and he believes that
Agarclh mistook the hairs or paranemata
for them.

BIBL. Harvey, Mar. Alg. 37, pi. 6 C ;
Tliyc. Br. pi. 91; Grev. Alt/. Br. pi. 10;
Agardh, Sp. Alg. i. 112; Nageli, Algensyst.
IfeO, pi. 5 ; Thuret; Ann. Sc. Nat. 4 ser. iii.

12 ; Kiitz. Phyc. gen. pi. 22 ; Al. Braun,
Rejuvenescence, Ray Sac., 1853, 79.

PALMEL'LA, Lyngbye (Red snow and
gory dewr). — A genus of Palmellacece (Con-
lervoid Algse), of which the best known
example is the common P. cruenta (PL 7.
tig. 3 a). This plant, very common on damp
walls in shaded places, appears at first in
the form of rosy gelatinous patches ; these
spread and become confluent until the mass
extends sometimes over a great extent of
surface, as a tough, gelatinous, irregular
mass, of the colour and general appearance
of blood ; when dried up in this state, it
forms a horny, somewhat crumbling stra-
tum ; if placed in water, portions float to
the top in pellucid rosy masses of jelly.

When placed under the microscope, the
frond appears to be composed of a colourless
homogeneous jelly, in which are imbedded
globular cells, single or in pairs (from divi-
sion), of a beautiful rose-colour (fig. 3, a, b) ;
by the application of reagents, these may
be shown to possess a proper membranous
coat (c). The contents of the cells appear
uniformly granular (6, c) ; and it would
appear that, besides increasing by division,
the cells also burst and discharge their con-
tents, since patches of minute granules occur
imbedded in the jelty (lower figs, of 6), pro-
bably de.vtined to grow up into the ordinary
cells. No zoospores, nor the remarkable
phenomena generally that occur in Proto-
coccus, have yet been observed in this, which
appears to be a very distinct genus. The
jelly of full-grown fronds (which appears to
be derived from the gelatinous softening of
the coats of the parent cells of the successive
generations of cells) is often overgrown and
discoloured by minute filamentous struc-
tures, which at first sight seem to belong to
it ; but on the application of a high power
are found to consist of a very minute Nos-
tcchaceous plant, apparently the Anabaina
subtilissima of Kiitzing, or Vibrio bacillus,
Ehr. (PL 7. fig. 21), which we find to occur
commonly among the Palmellaceous AlgaB.
From the examination of specimens of
the true "red snow," brought home by
Captain Parry, we incline to regard this as
a Palmella, distinct generically from the
Protococcns or Hcematococcus pluvialis of
German writers, with which it is commonly
associated. Our specimens consist of a
tough, colourless, gelatinous substance, con-
taining globular cells differing only in size
(PI. 7. fig. 3 d) from those of Palmella cru-
enta ; and in the jelly occur also abundance

PALMKLLACK K.

[ 574 ]

PALMELLACKK

of the minute granules or cells, which are
the discharged contents of the larger cells.
The red cells of the red-snow plant turn
green when exposed to light, if kept moist.
An exactly similar plant has been given us
by Mr. Oliver, from Crag Lough, North-
umberland, in a fresh condition; and we
have never been able to detect any moving
forms in it. Further particulars are given
under RED SNOW and WATER. Several other
species of Palmetto, are described ; but most
of them are too imperfectly known to allow
of definite characters being given ; P. rosea
is perhaps a good species. The forms with
a definite frond formerly placed here (P.
protuberans, botryoides, &c.) will be found
under COCCOCHLORIS.

BIBL. Eng. Bot. pi. 1800 ; Greville, Alg.
pi. 205; Meneghini, Tr. Turin Ac. 2. v.
pi. 6 ; Hassall, Alg. pi. 80 ; Nageli, Alg. 66,
pi. 4D; Kiitz. Sp. Alg. 211; Rabenht.
Aly. iii. 32. See also RED SNOW, and Pno-
TOCOCCUS.

PALMELLA'CE^E.— A family of Con-
fervoid Algse, consisting of gelatinous or
pulverulent masses, growing on damp sur-
faces, in fresh water or in the sea ; composed
of globular or elliptical cells, either more or
less adherent together into a definite or
indefinite pseudo-membrane or frond, or
loosely aggregated within a definitely or
indefinitely formed gelatinous matrix, or
loosely coherent in the form of a pulverulent
crust. Some authors have imagined that
the cells of Coccochloris or Palmella are at-
tached to filaments included in the gelatinous
frond: this seems an error (see PALMELLA).
Yellowish or bluish-green, or red, often
varying from green to red, and vice versa,
during the course of development. In-
creased by cell-division into two or four,
and by ciliated zoospores. Many exhibit
three forms: — 1. active; 2. quietly vege-
tating by subdivision; 3. resting form,
with a tough membrane. We include here,
for the sake of convenience, not only the
true Palmellacese, where there is a frond
composed of a number of cells held together
by mucus, but also all those Unicellular
Algse which, from their mode of increase,
are found living socially or in masses which
appear like Palmelloid plants.

Synopsis of Genera.

* Cells immersed in a colourless gelatinous
frond. f Frond amorphous.

Palmella. Frond a slimy stratum, crowded

with rather large globular green and red
cells, multiplying by division (PI. 7. fig. 3).
Microhaloa. Frond mucoid, floating in
water, densely crowded with minute cells,
multiplying by division, green or red.

tt Frond dejinite.

Glceocapm. Cells enclosed in wide gela-
tinous coats, enclosed in similar wide gela-
tinous parent coats for several generations
(PI. 7. figs. 4 & 13).

Botrydina. Frond globose, the periphery
composed of cells cohering into a kind of
cellular epidermis ; inner cells free (PI. 7.
%. 9).

Coccochloris. Frond gelatinous, globose,
containing numerous distinct cells, all free
(PL 7. fig. 6).

Clathrocystis. Frond gelatinous, at first
globose, then hollow and broken into a
coarse net, crowded with minute cells (PI.
5. fig. 9).

Merismopcedia. Frond very minute, flat,
square, containing cells in families of four,
sixteen, and sixty-four (PI. 7. fig. 12).

Urococciis. Frond composed of striated
gelatinous tubes, formed of the parent cell-
membranes in a single row, with solitary
or binary cells in the ends (PL 7. fig. 7).

Hormospora. Frond a wide, gelatinous,
simple or branched sheath, containing a
single row of cells in twos or fours (fig. 336,
p. 395).

Tetraspora. Frond gelatine us, foliaceous;
cells in fours, becoming free as zoospores
(PI. 7. fig. 10).

Hydrurus. Frond toughly gelatinous,
filiform, containing imbeddecl longitudinal
rows of cells (PI. 7. fig. 8).

Palmodictyon. Frond gelatinous, filiform,
branched; branches anastomosing into a net,
consisting of large vesicular cells, with co-
loured contents which escape as zoospores.

** Cells singk, either solitary or united
small numbers into families (Unicellular

Schizochlamys. Cells free, globular, green,
aggregated in a jelly, each dividing into 2
or 4 portions, set free by the parent cell
breaking into 2 or 4 segments.

Chlorosphcera. A large free globose cell,
with green contents, ultimately dividing
into two cells, each forming a new cell like
the parent, set free by lateral rupture (PI, 5.
fig. 4).

Characmm. A minute attached, pyriform,
fusiform, or rounded, shortly stipitate sac

PALMELL1NA.

[ 675 ]

PALUDICELLA.

containing green protoplasm, which by re-
peated binary division forms a swarm of
active 2-ciliated zoospores escaping by a
lateral or terminal slit (PL 5. fig. 2).

Apiocystis. A simple attached sac with
a stout membrane, with green contents, |
consisting at first of groups of four still j
gonidia, which subdivide repeatedly, and as
the parent sac grows become converted into
innumerable active zoospores, which move
in the parent sac and then break out in a
swarm (PI. 5. fig. 5).

Codiolum. An attached small, long cla-
vate sac, forming a stipes below, filled with
granular green contents, with starch-corpus-
cles, finally converted at once into nume-
rous globose gonidia, escaping by rupture of
the sac (PL 5. fig. 6).

Hydrocytium . An attached minute shortly
stalked oblong sac, with green contents, ancl
a parietal starch-corpsule. Contents finally
divided into numerous 2-ciliated zoospores,
breaking out in a swarm (PL 5. fig. 1).

Ophiocytium. Single or rarely in families ;
composed of a minute cylindrical curved
sac, with a short stipes, free or attached ;
green contents scattered, finally forming 8
gonidia in a row, set free by the circumscissile
rupture of the end of the sac (PL 5. fig. 11).

Sciadium. At first a stalked tubular sac,
with 8 gonidia, which grow from the orifice
in an umbel, finally emitting 2-ciliated zoo-
spores (PL 5. tig. 3).

Chytridium. A minute parasitic globu-
lar or urceolate rooted sac ; cell-contents
colourless, finally converted into 2-ciliated
zoospores (PL 5. fig. 7).

Pythium. Parasitic ; a colourless globu-
lar sac, living in the interior of diseased
Confervoids, often in groups, the neck per-
forating the nurse-plant, emitting active
gonidia (PL 5. fig. 8).

BIBL. Braun, Rejuven., Ray Soc. 1851 ;
Alg. Unicell. 1855; Chytridium, 1856;
Nageli, JEinzell. Algen, 1849; Kiitz. Spec.
Alg. and Tab. Phycol. i. ; Cohn, Nova Acta,
xxiv. ; Rabenh. Alg. iii. ; Cooke, Fresh-
water Alga, 1882.

PALMELLI'NA, Radlk.— A doubtful
genus, allied to Palmella, or probably Fungi.
Thallus fl occulent; cells very minute, some
smaller and globular, others larger, elliptical
or elongate. In the mud of wells and
fountains; and beneath the epidermis of
the scalp !

BIBL. Rabenh. Aly. iii. 35.

PALME'RIA, Grev.— A genus of Dia-
tomacese from Hong Kong.

BIBL. Grev. Ann. N. H. 1865, xvi. 1.

PALMICELLA'RIA, Alder.— A genus
of Escharidae (Cheilostomatous Polyzoa).
Orifice of the capsules with a palmate or
mucronate process, with an avicularium on
its inner aspect. Four species; marine,
deep water. (Hincks, Br. Zooph. 378.)

PALMITIC ACID is a constituent of
most neutral animal and vegetable fats ; it
exists in combination with glycerine, form-
ing palmitine. When crystalline it forms
pearly scales.

PALMODAC'TYLON, Nag.— A sup-
posed genus of Unicellular Algae, germina-
ting spores of a Moss ?

P. varium consists of a group of radiating
single cells, or short multicellular filaments ;
ends rounded; numerous green masses in
each cell. The cell-wall bursting in definite
directions, sets free active gonidia. In
freshwater pools.

BIBL. Nageli, Einzell. Alg. pi. 2. fig. B ;
Rabenh. Alg. iii. 43.

PALMODIC'TYON, Ktz.— A genus of
Palmellaceae (Confervoid Algae). Frond
forming a delicate gelatinous network, com-
posed of single or double rows of large vesi-
cular cells, 1-600 to 1-960" in diameter;
containing a pair of elliptical green cellules,
1-3000" in diameter, which ultimately es-
cape as active zoospores. This genus ap-
pears identical with Trypothcdlus, HOOK.
and Harvey, and is nearly related to HY-
DRTJRUS and TETRASPORA.

P. rtifescens, Ktz., doubtfully referred
here, is larger ; it occurs near Aberdeen.

BIBL. Kiitz. Sp. Alg. 234; Tab. Phyc.
Bd. i. pi. 31 ; Rabenh. Alg. iii. 37.

PALMOGIXEA, Ktz. See Cocco-

CHLORIS.

BIBL. Archer, Qu. Mic. Jn. 1864, 124;
Rabenh. Alg. iii. 116.

PALMOPHYL'LUM, Ktz.— A genus of
Palmellacese (Confervoid Algae). 1 species,
found in the Adriatic.

BIBL. Rabenht. Flor. JEur. Alg. iii.
49.

PALUDEL'LA, Ehr.— A genus of Mee-
siaceae, having only one representative,
which occurs in Britain, P. squarrosa =
Bryum squarrosum, L.

PALUDICEL'LA, Gervais.— A genus of
Polyzoa.

Char. Polyzoary fixed, filamentous, dif-
fusely and irregularly branched, coriaceous,
consisting of a single row of club-shaped
cells arranged end to end ; apertures unila-
teral, tubular, placed near the broad end of

PAMPHAGUS.

[ 576 ]

PAPER.

each cell ; tentacular disk circular, with a
single row of free tentacles.

P. articula'a. The only species; olive-
green ; polypes ascidian. Freshwater ; dia-
meter of filaments about 1-30 to 1-20".

BIBL. Johnston, Br. Zooph. 405 ; All-
man, Ann. N. H. xiii. 331, and Pr. Irish
Ac. 1843.

PAM'PHAGUS, Bailey. — A genus of
Rhizopoda allied to Lieberkuehnia. P. mu-
tabilis is amcebiform, covered with a delicate
elastic integument. Bailey, Amer. Jn. Soi.
xv. ; Pritchard, Inf. 551 ; Claparede et
Lachmann, Etudes, 465; Archer, Qit. M. J.
1871, 101.

PANDORFNA, Bory (PI. 5. fig. 10).—
A genus of Volvocineas (Confervoid Algae),
which we believe to be synonymous with
Eudorina. It exhibits a great variety of
forms, some of which have been described
under the name of P. Morum, others otEud.
eleyans. The most characteristic conditions
are represented in PI. 5. tig. 10. Pandorina
stands midway between Volvox and Ste-
plianosplicera, — consisting of an ellipsoidal
translucent gelatinous sac, containing im-
bedded just within its surface, several zone-
like rows of green pear-shaped gonidia,
whose two cilia penetrate the gelatinous
envelope, and, hanging out free, move the
entire organism by their vibration. Two
distinct forms occur — one with sixteen, the
other with thirty-two gonidia. Where
sixteen occur, there are four zones of four
gonidia, while where thirty-two exist they
stand in four zones of eight, with four at each
end(Pl. 5. fig. 10 a and 6). The gonidia
have a red spot and a vacuole, like those of
Gonium and Volvox. These two forms
occur together; and evidently the difference
arises simply from an additional binary sub-
division of the gonidia in the earlier stages
of development from the spore. They are
often so numerous as to tinge the water of
fresh pools green, like Volvox and Proto-
coccus. They occur of various sizes, from
1-80" downwards.

These forms are multiplied vegetatively
by the conversion of each gonidium into a
family like the parent, each group acquiring
its special envelope and becoming free by
the solution of the parent-envelope. Two
corresponding forms also occur with the
above, with the sixteen or thirty-two goni-
dia closely crowded together, instead of
standing at wide intervals in the large
colourless envelope.

The resting-spores are formed out of all

or part of the gonidia of a family, after
conjugation (h'g. 139*, p. 205). The impreg-
nated gonidia soon acquire a stout special
coat, and their originally green contents
turn red ; they become free by the solution
of the parent-envelope. In germination
they turn green again, and by repeated
division of their protoplasm, form the new
families of sixteen or thirty-two, constitu-
ting the perfect plant.

Fertilization of the gonidia has also been
described as being produced by tho action
of spermatozoids — minute, fusiform, ciliated
corpuscles, produced in large numbers by the
subdivision of certain of the gonidia. 'This
seems doubtful.

BIBL. Ehr. Inf. 53; Duj. Inf. 317;
Henfrey, Mic. Tr. 2. iv. 49; Fresenius,
Mus. Senckenb. ii. 187 ; Cohu, Nova Acta,
xxvi. 1 ; De Bary, Sot. Zeit. xvi., 8upp. ii.
73;Currey, Q. Mic. Jn. vi. 213; Carter,
Ann. N. H. 3 ser. ii. 237; Rabenhorst,
Ale/, iii. 99; Pringsheim, Monatsb. Berl.
Ak. 1869 ; Sachs, Bot. 258.

PANNA'RIA, Del.— A genus of Placodei
(Lichenaceous Lichens). Several species.
(Leighton, Lich. Fl. ]50.)

PANOPH'RYS, DUJ. = FRONTONIA pt.

P. chrysalis (PI. 31. fig. 55). Marine.

BIBL. Duj. Inf. 491 -j Claparede & Lachm.
Etudes, 260.

PANTOT'RICHUM,Ehr.— A genus of
Infusoria.

P. laffenula, E. (PI. 31. fig. 58). Body
ovate, equally rounded at each end, yellow-
ish ; tegument produced in front in the
form of a neck or truncate rostrum ; length
1-1080 to 1-580".

BIBL. Ehrenberg, Inf. 247; Dujard. Inf.
388 ; Clap, et Lachra. Inf. 315.

PAPER. — A few general observations
only can be made under this head. Ordinary
paper, as is well known, was generally manu-
factured from rags of linen or cotton fabrics,
so that it consisted of a kind of felt of the
fibres of cotton or flax ; but in consequence
of the immense demand for paper, other
substances, such as straw, jute, esparto, the
pulped woody fibres of the poplar and pine,
are now largely used. The manipulation
to which the material is subjected, together
with the effect of frequent washing in the
case of rags, affects the characters of the
fibres to some extent ; and the cellulose is
in some cases already brought into that
state in which iodine colours it blue. The
addition of sulphuric acid and iodine colours
the fibres of most papers blue ; and care

PAPER.

must be taken on this account to avoid
errors from the accidental presence of- them
when blotting-paper is used to absorb these
reagents when applied to objects on a slide.
The determination of the nature of the fila-
ments of which a paper is composed, by the
aid of the microscope, requires a thorough
knowledge of the characters of vegetable
fibres. The structure of the various fibres
is noticed under the individual heads. Lat-
terly the use of the fibres of the purple bog
melic-grass, Molinea ccerulea, has been in-
troduced.

Rice-paper, as it is termed, is a totally
different material, consisting of thin layers,
cut by a peculiar operation, of the pith of
Aralia papyri/era, a Chinese Araliaceous
tree : this consists of parenchymatous cel-
lular tissue.

Papyrus, consisting of pressed superposed
laminae of the pith of the Papyrus plant,
Papyrus antiquorum, a kind of Sedge, ex- \
hibits the lax parenchymatous structure
characteristic of similar tissues, as in the
Rushes, &c.

PAPER, METEORIC, and AEROPHYTES. —
The structure of these substances is the !
same as that of the so-called natural flannel
(FLANNEL). They were formerly regarded i
as of meteoric origin. They have been ob-
served in some instances to fall from the
air, having been wafted perhaps many miles
from their place of formation by whirlwinds
and hurricanes.

BIBL. Ehr. Abhandl. d. Berl Akad.
1838.

PAP'PUS.— The free portion of the
calyx of the Composites. It may be
feathery, spiny, membranous, or hairy.

PAPULAS'PORA, Preuss.— A genus of
Mucedines (Hyphomycetous Fungi), con-
sisting of a decumbent articulate mycelium
sending up erect pedicels bearing a cellular
head, each cell supporting an oblong spore.

P. sepedonioides has been found on rice-
paste.

BIBL. Berk, and Broome, Ann. N. H. 2.
xiii. 462 ; Berk. Crypt. Bot. 305, fig. 69 b.

PAPY'RUS.— The pith of the stem of '
the Papyrus antiquorum (modern papyrus :
from P. syriacus), cut into slices, which are j
laid upon one another and pressed so as to \
form a compact stratum. Sections display \
the parenchymatous tissue more or less de- j
formed bv pressure.

PARACY'PRIS, Sars. — A genus of
Cypridce (Entomostraca), near Aylaia and
Potamocywis. One British species, rather j

PARASITES.

common, marine ; also fossil in raised
beaches, &c. (Brady, Linn. Tr. xxvi. 377.)

PARADOXOSTOMA, Fischer.— A ge-
nus of CytlieridcB (Entomostraca). Valves
thin, smooth, elongate, compressed, sub-
ovate or subtriangular ; mouth simple, tubi-
form ; five joints in the lower, six in the
upper antennae, the last very slender.
Marine; 13 British species. P. variabile
very common, fossil in raised beaches, &c.
(Brady, Linn. Tr. xxvi. 456.)

PARAME'CIUM, Hill, Ehr.— A genus
of Holotrichous Infusoria, family Colpodina.

Char. Body compressed, covered with
cilia ; no eye-spot ; mouth lateral and with-
out projecting cirri.

Several species, freshwater and marine.

P. aurelia (PI. 31. figs. 56 and 57). Body
cylindrical, ovate-oblong, rounded or obtuse
at the ends, with an oblique longitudinal
fold extending to the mouth. Length 1-120
to 1-100" ; in vegetable infusions.

This common infusorium shows well the
curious star-shaped contractile vesicles.
Ehrenberg notices in it the periodical occur-
rence of small black crystalline particles at
the anterior end. The depressions on the
surface of the integument (PL 32. fig. 1) are
distinctly seen in the dried animal ; tri-
chocysts are present.

P. chrysalis, E. (Pleuronem'.i crassum, D.
PI. 32. fig. 37, undergoing division) . Body
oblong, cylindrical; oral cilia very long.
Length 1-240".

BIBL. Ehr. Inf. 349; Duj. Inf. 481;
Stein, In/us. ; Claparede et Lachmann, In/us.
265 ; Kent, Inf. 483.

PARAM'ONAS, Kt.— A genus of Fla-
gellate Infusoria. Free, ovate or globular,
one fiagellum, a distinct mouth at its base.
Four species, white, red, or green ; fresh-
water. (Kent, Inf. 370.)

PARAPHY'SES.— The name applied
to more or less delicate- jointed, hair-like
filaments which occur in small numbers
around and between the antheridia and
archegonia of Mosses and Hepaticse (fig. 23,
p. 57, fig. 327, p. 388). The same term is
applied to simple tubular, more or less
clavate cells, occurring in large numbers
among the spore-sacs (asci and thecce) of
the Ascomycetous Fungi and the Lichens
(fig. 40, p. 78; fig. 398, p. 463; PI. 37.
figs. 6, 12).

PARAPONTEL'LA, Br.— A genus of

Copepodous Entomostraca. P. brevicornis,

marine. (Brady, Copepoda, Ray Soc. i. 68.)

PARASITES.— Under this head are in-

2p

PARASITES.

578 ]

PARASITES.

eluded a number of microscopic animals
and plants infesting other animals and
plants, and often nourished at the expense
of their structures or juices. Almost every
animal and plant is subject to parasites,
both in the young and the adult state ; and
in some instances, the parasites are them-
selves infested by other parasites. The
parasite may live on the surface of the
parasitiphore or host, or within its tissues
and in the cavities of its organs ; hence the
division of parasitic animals into epizoa
and entozoa. The commonest parasites
either feed upon the decaying external
skin -tissues, or are nourished at the expense
of the blood and fluids. In some remark-
able instances, as in the cirripeds, the male
appears to live parasitically upon the fe-
male; and in almost every case of para-
sitism there is a complicated life-cycle, often
accompanied by strange adaptations and
degenerations of form, so that often the j
parasite ultimately resembles but slightly its j
free and primitive form. Of the Animal
Parasites, many are not microscopic, but
the following sketch may be useful for
reference. The chief portion belong to : —
The CRUSTACEA, Order Siphonostoma, as
Caligus, Cecrops, Lcemaryus, Nicothoe. The j
ABACHNIDA, Ord. Acarina, as Sarcoptes,
the itch-insect j the Ixodea, or ticks ; the
Gauiasea, on insects ; Trombidium, the
harvest-bug; the Hypoderidee, in birds;
the Phytoptidse, in galls. The Insects,
especially the Anoplura, as Hcematopinus,
Pediculus (the louse), and Phthirius ; Pedi-
cinus', and Trichodectes. The ENTOZOA,
as Tcenia (Ccenurus, Cysticercus, Echino-
coccus) ; Distoma, in the liver; BiUiarzia,
in the human blood-vessels, the ova in the
urine in endemic hsematuria and chyluria ;
the Nematodes, Anyuillula infest, and ster-
coralis, and Dochmius, in tropical diarrhoea ;
Sclerostoma syngamus in poultry, producing
the " ga^es ;" Strongylus pergracilis in the
Grouse-disease. The Infusoria, Opalina,
Trichomonas, &c. ; and the GBEGABINIDA,
Psorospermia in mammals, and insects
(PEBBINE).

These are described under the respective
heads.

The Plants parasitic on animals chiefly
belong to the class of FUNGI, and are tole-
rably numerous ; but many of the forms
which have been described are certainly
not distinct plants. They will be most con-
veniently enumerated under the heads of
the classes of animals infested.

Man and Mammalia.
On the Skin. — ACHOBION Schoenleinii and
PUCCINIA favus, on the hair and in the
follicles, in favus. TBICHOPHYTON ton-
surans, on the hair in plica polonica and
favus; this appears to be a TVww/a-like
growth, probably not a mature plant. TV.?
sporuloides, Rob., occurs in plica ; and Tr.?
ulcerina, Rob., in the pus of ulcers. Micro-
sporon Audouinii occurs in the hair-fol-
liclos in porrigo decalvans ; M. mentayro-
phytes. on the beard &c. ; M. furfur, on the
skin of the chest &c. in pityriasis versicolor.
The occurrence of Mucor mucedo on the
skin, and of an Asperyillus in the external
conduit of the ear, must be regarded us
accidental.

On the mucous surfaces or in cavities. —
SABCINA ventriculi in the stomach ; Tomla
cerevisice (?), ditto. Various species of
LEPTOMITUS, which must be regarded as
imperfect mycelial growths, found in almost
all the cavities of the body. Oidium albi-
cans, the fungus of aphtha, probably a pe-
culiar condition of PENICILLIUM ; Lcj)/<>-
tlirix buccalis, a filamentous growth constant
between the teeth, probably some allied
mycelium.

Birds.

Various species of ASPERGILLUS have
been found in the lungs and air-sacs ; their
introduction would appear to be accidental.
In the eggs of the common fowl, DACTY-
LIUM oogenum occurs not unfrequeutly,
sometimes on the membrane of the yolk,
sometimes on the outer membrane/ just
beneath the shell. — SPOBOTBICHUM brun-
neum, Schenk, in the white of eggs, convert-
ing it into a brownish gelatinous mass.

Reptiles and Fishes.

On the skin of Tritons, as of Fishes,
ACHLYA (Saproleynia) is frequently ex-
tremely developed ; other obscure forms are
also enumerated by Robin. The same author
describes the PSOBOSPEBMI^E as Algse allied
to the Diatomaceae ; but they are pseudo-
naviculae of GBEGABINA.

Berkeley has recorded the occurrence in
Denbighshire, on the scales of goldfish, of a
lichen identical with one which is found on
stones in neighbouring streams.

Insects

are subject to the invasion of various para-
sitic fungi, among the most remarkable of

PARASITES.

[ 579 ]

PARMELIA.

which is the Muscardine of the Silk-worm,
BOTRYTIS bassiana, which sometimes occa-
sions enormous loss to the silk-cultivators.
This fungus grows in or upon any part of
the silk- worm, Bombyx mori, in its larva,
chrysalis, and imago forms. It is not fully
developed until after the death of the insect ;
but if the spores penetrate the body of a
living specimen and this is placed in a damp
and confined atmosphere, the germination
takes place, and a development of the fungus
ensues, which destroys the tissues and organs,
finally causing death. It has been developed
on many other Lepidoptera which have
been inoculated with it ; and even the larvae
of certain Coleoptera take it. It is very
common to find flies in autumn infested
with a fungus, a kind of muscardine of flies :
this belongs to the genus SPORENDONEMA ;
its mycelial filaments ramify in the interior
of the body, and emerge at the articulations
of the segments of the abdomen to bear fruit,
killing the fly. A number of so-called genera
of Fungi and Algae have been described by
Robin and Leidy as occurring in the intes-
tines &c. of insects : these appear to us to
be imperfect organisms (see ENTEROBRYUS,
ARTHROMITUS, LEPTOTHRIX, CLADOPHY-
TUM). Several species of Cwrdyceps infest
the larvae of insects, the mycelium destroy-
ing them and gradually completely dis-
placing the internal organs, while the skin
retains its shape and dries ; the fruit sub-
sequently breaks out from the anterior or
posterior extremity (see SPH^RIA). Some
species of ISARIA, described as parasites,
grow upon dead insects ; but these are mere
conditions of different species of Cordyceps.

The microscopic vegetable parasites of

Plants

are very numerous, all belonging to the class
of Fungi. Much confusion "exists in many
works between the true parasites and mere
epiphytes ; and it is sometimes very difficult
to draw any line of demarcation. Among
the undoubted parasites are all the genera
and species of the familyUREDiNEi, together
with a large portion of the other genera of
Couioinycetes and the Asconiycetous forms
to which they mostly belong. Among the
Hyphomycetes may^especially be cited the
genus PEROXOSPORA, P. infestans being the
potato-fungus. FUSISPORIUM, OJDIUM, &c.
form destructive mildews ; and among the j
ASCOMYCETES, the ERYSiPH^J, and espe- i
cially their inycelia (commonly forming |
spurious Oidia), are well-known pests, j

Further particulars are gi ven under POTATO -
FUNGUS (Botrytis m/£afon0),Yntx-Ft7N<}u8,
and BLIGHT. The organisms described as
Unicellular Algae, under the names of
CHYTRIDIUM and Pythium, are parasitic
on Confervoids.

BIBL. Robin, Veget. Parasit. ; Baeren-
sprung, Ann. N. H. xii. ; Siebold, Wagner's
Hand. d. Phys. ; Hannover, Mutter's Arch.
1842 ; Bennett, Ed. Phil. Tr. xv. ; Archer,
Qu. Mic. Jn. 1872, 366 ; Cobbold, Parasites ;
Leuckart, Mensch. Parasit. 1881 ; Murie,
Mn. M. Jn. vii. 149 ; Maddox, Mic. Tr. 1866 ;
Beneden, Schmarotzer,1876 -, Hallier, Phijto-
pathol. 1868; Kaltenbach, Pftanzenfeinde
(Insects)) 1872; Giebel, JSpvtoa (Insects) ,
1874; Douiion, Par. diar. Cochin- China;
Gurlt,Arch. Naturgesch. 1878, 162 ; Hartig,
PftanzenKr. (Fangi), 1880; Frank, Krankh.
Pft. (Fungi), 1880; Heller, Schmarotzer,
1880 ; Megnin, Paras. 1880 ; Ornierod, In-
jurious Insects, 1881 ; Cohn, Paras. Algce
Beitrage, i. 87 ; Kiichemneister, Parasiten,
1881 ; Bollinger, Pilzkrankh. nied. und
Jwh. Thiere, Bot. Centralblatt, ii. 274 (Jn.
Mic. Soc. 1881, 492) ; Hallier, Zeitschr.
Paras. Kunde.

PAREN'CHYMA. See TISSUES, Vege-
table.

PARKE'RIA, Carpenter. — A large
spheroidal Arenaceous Foraininifer, attain-
ing 3 inches and more in diameter, and
consisting of a chambered conical centre-
piece (primordial chamber-cone) surrounded
by numerous concentric lamellae and their
interspaces, traversed and connected by
radial tubes, all of cancellated (labyrinthic)
structure. Fossil in the Greensand.

BIBL. Carpenter, Phil. Trans. 1869, 721.

PARKE'RIA, Hooker, = CERATO-

PTERIS.

PARME'LIA,Ach. — An extensive genus
of Parmeliaceae, characterized by the spread-
ing, lobed, foliaceous thallus, with orbi-
cular apothecia fixed by a central point
beneath ; spores simple ; growing upon
trees, palings, rocks, stones, walls, &c.
The species with bilocular spores form the
genus Physcia. P. parietina, the yellow
wall-lichen, is one of the commonest plants
of this family, and furnishes a ready means
of observing the structure both of the
apothecia and the spermogonia (PI. 37.
figs. 1-3).

BIBL. Hook. Br. Fl. ii. pt. 1. 202 ; Engl
Bot. pi. 194 ; Sehaerer, Enum. Lich. Europ. ;
Tulasne, Ann. Sc. Nat. 3. xvii. 66, 137 ;
Leighton, Lich. Flora, 114.

PAKMELIACE^E.

]

PATELLIXA.

PARMELIA'CE^E.— A family of open-
fruited Lichenaceous Lichens, bearing ses-
sile shields, the borders of which are formed
by the surface of the thallus. This family
corresponds nearly to the series Bamalodei,
Phyllodei, and Placodei, of the family Li-
chenacei in Leighton's Brit. Lich. Flora.

British Genera.

* Apothecia at first veiled, thallus horizontal :
Peltigeri.

Peltiyera. Thallus foliaceous, leathery
or membranous, spreading, lobed, witn
woolly veins beneath. Apothecia somewhat
circular, adnate on the upper side of the
lobules of the thallus, with a border formed
by this.

Nephroma. Thallus foliaceous, leathery
or membranous, spreading, lobed, naked or
hairy beneath. Apothecia circular or reni-
form, adnate on the underside of the lobules
of the thallus, with a border formed by the
latter.

Solorina. Thallus leathery, membrana-
ceous, veined or fibrillose oelow. Apo-
thecium suborbicular, affixed to the upper
surface of the central lobes of the thallus ;
veil finally forming an evanescent margin.

** Apothecia at first closed, thallus horizontal :
Euparmeliacei.

Sticta. Thallus foliaceous, leathery-car-
tilaginous, spreading, lobed, free and downy
beneath, with little cavities or hollow spots,
often containing a powdeiy substance. Apo-
thecia beneath formed of the thallus, to
which they are appressed and fixed by a
central point, the disk coloured, flat, sur-
rounded by an elevated thalline border.

Parmelia. Thallus foliaceous, membranous
or leathery, spreading, lobed and stellated
or laciniated, more or less fibrous beneath.
Apothecia circular, formed by the thallus,
fixed by a central point, disk concave,
coloured, with an inflexed margin from
the thallus.

Urceolaria. Thallus uniform, crusta-
ceous. Apothecia urceolate, somewhat im-
mersed, the thalline border somewhat di-
stinct.

Lecanora. Thallus crustaceous, spread-
ing, flat, adnate and uniform. Apothecia
circular, thick, sessile and adnate; disk
plano-convex, the border thickish, formed
of the crust, and of the same colour.

Physcia. Thallus cartilaginous, branched
and laciniated, the segments free, generally
grooved beneath, the margins frequently

cili ated . Apothecia circ ular, peltate, formed
of the thallus, the disk coloured and sur-
rounded by an inflexed thalline margin.

*** Apothecia open from the first, thallus
mostly centripetal, vertical or sarmen-
tose, without any In/pothalhts : Usnei.

Cetraria. Thallus foliaceous, cartila-
gineo-membranous, ascending or spreading,
lobed and laciniated, smooth and naked on
both sides. Apothecia circular, obliquely
adnate to the margin of the thallus, the
lower portion being free (from the thai] us) :
disk coloured, plano-concave, with an in-
flexed thalline border.

Roccella. Thallus cartilaginous, leatb TV.
rounded or flat, branched or laciniate.
Apothecia circular, adnate to the thallus,
disk coloured, plano-convex, with a thalline
border, at length thickened and elevated,
and covering a black powder concealed
within the substance of the thallus.

Ramalina. Thallus cartilaginous, gene-
rally branched and laciniated, somewhat
shrubby, generally bearing powdery wnrls.
cottony and compact within. Apothecia
circular, shield-shaped, stalked and peltate,
flat, bordered, entirely formed of the sub-
stance of the thallus, and mostly of the
same colour.

Cornicularia. Thallus cartilaginous,
branched, subcylindrical, fistulose, or nearly
solid and cottony within. Apothecia cir-
cular, terminal, obliquely peltate, entirely
formed of the substance of the thallus, at
length convex, more or less bordered and
often toothed.

Evernia. Thallus somewhat crustaceous,
branched and laciniated, angled or com-
pressed, cottony within. Apothecia circular,
shield-shaped, sessile, with the disk concave,
coloured, and an inflexed border formed by
the thallus.

Ustwa. Thallus somewhat crustaceous,
rounded branched, generally pendulous,
with a central thread. Apothecia circular,
terminal on processes of the thallus, peltate,
nearlv of the same colour, mostly without a
raised border, but ciliated at the margins.

BIBL. See the genera.

PASTE, EELS IN. See ANGUILLULA.

PATELLI'NA, Will.— A genus of Hya-
line Foraminifera, of the Eotaline family.

Trochoid, formed of a low cone of sub-
•_ spiral, semiannular, and annular chambers,
divided into chamberlets. Sometimes in-
crusted with small cells externally, and

PAYOXINA.

[ 581 ]

PEDALION.

always having the hollow face coated or
filled up with superimposed chamberlets,
forming a columnar chamber-structure.

British 'species, P. corrugata (PI. 24.
fig. 8), rare : abundant in tropical seas ; and
of larger size in some Cretaceous and Ter-
tiary strata.

BIBL. Williamson, Rec. For. 46 ; Carter
( Conulites and Orbitolina), Ann. N. H. 3.
viii. 331, 457, 459 ; Carpenter, Introd. For.
299.

PAVONI'NA, D'Orb.— A Hyaline Fora-
miuifer, compressed andflabellifprm; cham-
bers concentric, the last widest, with
numerous marginal apertures. It is a flat
Bigeuerine Textularia. Madagascar, Pacific,
and West Indies.

BIBL. Brady, Ann. N. H. 4. xix. 105 5
Qu. Mic. Jn. n. s. xix. 68.

PAXIL'LUS, Fr.— A genus of Agaricini
(Hymenomycetous Fungi) with the margin
of the pileus involute, the gills decurrent,
anastomosing, and separable from the pileus
and without any trama. Paxillus involutus
is a very common species ; and to this the
characters of the genus more especially
apply. P.pannoides occurs on sawdust in
cellars &c., and is closely allied to Merulius.

BIBL. Fr. Gen. Hym. 8; Berk. Outl.
t. 12. fig. 5; Cooke, Handb. 194.

PEARLS.— These well-known bodies are
formed as secretions from the mantle of
bivalve mollusks, the best being obtained
from the Ceylon pearl-oyster or mussel
(Avicula margaritifera). They occur natu-
rally from the irritation produced by particles
of sand accidentally confined between the
mantle and the shell ; and they are produced
artificially by wounding, the mantle with
pieces of iron wire, &c. Their structure
agrees with that of the shell of the animal
in which they are formed. Sometimes they
consist entirely of nacre or pearly matter,
arranged in close concentric layers; at
others, the interior exhibits the prismatic
structure of shell. When acted upon by a
dilute mineral acid, the lime-salt is removed
from the organic cast of the original, which
is left. They are sometimes found fossil.

See SHELL.

BIBL. Hague and Siebold, Siebold $ Kol-
liker's Zeitschr. viii. 439 & 445 ; Carpenter,
Microscope.

PEB'RINE is the name of a disease
which for the past twenty years has raged
amongst the silkworms in France. In 1853,
the weight of cocoons produced in that
country was 26,000,000 of kilogrammes ; in

1865 it had fallen to 4,000,000. The black
spots which cover the larvse are a frequent
outward sign of the disease; hence the
name pebrine, first applied to the plague by
Quatrefages. It also declares itself in the
stunted and unequal growth of the worms,
in the languor of their movements, in their
fastidiousness as regards food, and in their
premature death. The cause of the disease
is the presence in the internal economy of
the larvse of Greyarinida ; their number is
often enormous. They take possession of
the intestinal canal, and spread thence
through the rest of the body. In particular,
the silk-secreting organs, instead of being
filled with the clear viscous liquid of the
silk, are packed to distention by these cor-
puscles. Pasteur in 1865 made out the
fact that they might exist in an incipient
condition in the eggs and larvae, although
it might be impossible to detect them. In
the moths, if either egg or larva from
which they come should have been at all
stricken, the corpuscles infallibly appear,
and there is no difficult}^ in detecting them.
In eradicating the disease, Pasteur, there-
fore, showed that it was of the greatest
importance to secure eggs from healthy
moths, since the healthy appearance of the
eggs themselves was not sufficient to secure
immunity. The larvse issuing from the
eggs of perfectly healthy moths may them-
selves become infected through contact
with diseased larvse, or through germs
mixed with the dust of the rooms in which
the silkworms are fed.

BIBL. Pasteur, Maladie des vers a soie;
Tyndall, Nature, 1870; Balbiani, Jn. Anat.
1866, 599 ; Robin, Micr. 948.

PECTIN ATEL 'LA, Leidy.— A genus of
freshwater Polyzoa, order Hippocrepia,
family Plumatellidse.

Char. Zoary massive, gelatinous, fixed,
investing ; orifices arranged in irregular
lobate areolas upon the free surface; ova
lenticular, with a ring and marginal spines.

P. magnified. Philadelphia.

BIBL. Leidy, Proc. Ac. Philadelphia,
1851 ; Allman, Freshwater Polyzoa, 81.

PEDA'LION, Hudson.— A genus' of
Rotatoria, family Hydatinsea. P. mirum
has the trochal disk very large, and recembles
Triarthra longiseta. The males are very
small, and deficient in most of the inrnal
organs ; freshwater.

BIBL. Hudson, Mn. Mic. Jn. 1871, 1872 ;
Qu. Mic. Jn. 1872, 333; Lankester, Qu.
Mic. Jn. 1872, 338.

PEDIASTRUM.

[ 582 ]

PELLIA.

PEDIASTRUM, Meven.— A genus of
Desmidiaceae (Confervoid Algae).

Char. Cells aggregated into a usually
circular, minute disk or flattened star, and
generally arranged either in a single or in
two or more concentric series; marginal
cells bipartite on the outside.

Ralfs describes eleven British species.
Interstices of the cells usually hyaline, but
in P. seleneeum these are greenish.

Braun divided the genera into four sub-
genera, which include twenty-nine forms
more or less worthy of being considered
genera.

P. Boryanum (PI. 14. fig. 48). Cells
arranged in one or more circles around one or
two central ones ; marginal cells gradually
tapering into two long subulate points;
notch narrow. Diameter of outer cells
1-2730 to 1-2200".

P. granulatum (PI. 14. fig. 49). Cells
six, granular or punctate on the surface;
lobes of marginal cells tapering. Diameter
of outer cells 1-1850".

The method of reproduction is noticed
under DESMIDIACEJE, p. 244.

BIBL. Rail's, Br. Desmid. 180; Braun,
Rejuv., Ray. Soc. 1853, pis. 3 & 4; Alg.
Unicell Gen. Nova, 64; Rabenh. Alg. iii. 69.

PEDICELLA'RI^E. See ECHINODEB-

MATA.

PI. 45. fig. 3 represents a pedicellaria
from the common starfish ; the stalk is not
figured.

The bird's-head processes of the Polyzoa
(POLYZOA) are analogous organs.

PEDICELLI'NA, Sara.— A genus of
Ctenostornatous Polyzoa, family Pedicelli-
nidae.

Char. Those of the family.

Bodies globose, with a circle of short
tentacles, curled inwards and not retractile ;
placed at the ends of erect slender stalks
springing from a creeping adherent fibre.
3 species.

BIBL. Johnston, Br. Zooph. 381 ; Allman,
Polyzoa, Ray Soc., 19, note; Hincks, Pofyz.564.

PEDICELLINI'D^E.— A family of Po-
lyzoa, containing the single genus PEDI-
CELLINA.

PEDICI'NUS, Gerv.— A genus of Pedi-
culidce; with the antennae 3-jointed, the
fourth and fifth being fused with the third,
the head elongate ; the legs all scansorial ;
abdomen broad. On Quadrumana. (Me*g-
nin, Paras. 76.)

PEDICTJLUS, L.— A genus of Anoplu-
rous Insects, of the family Pediculidas.

Char. Legs all scansorial or prehensile;
thorax large, not constricted from the abdo-
men, which has seven segments ; antennae
five-joir.tcd ; mouth A\ith a fleshy rostrum.

The species are human lice. The colour
varies according to that of the skin of the

nle they inhabit ; being darker in the
tribes.

Rostrum retractile, concealed beneath the
head, forming a soft tubular sheath dilated
at the end, where it is furnished with a
double row of hooks, and containing a horny
tube formed of four setae.

P. capitis. Ashy-white, thorax elon-
gated, quadrate, abdomen ovate, laterally
lobed, segments blackish at the margin.
Length of male, 1-10" ; of female, 1-8".

P. vestimentij bodjr or clothes' louse
(PI. 35. fig. 3). Dirty white, elongato-
ovate ; head much produced ; thorax con-
tracted in front; abdomen with the seg-
ments indistinctly indicated. Length about
1-8".

P. tabescentium, distemper-louse. Pale
yellow ; head rounded ; antennae long ;
thorax large and quadrate; abdomen large,
the segments intimately united. Doubtfully
British.

The extraordinary annoyance stated to
have been produced by these vermin, has
arisen from the want of washing- and puri-
fication of woollen garments.

See PHTHIRIUS.

BIBL. Denny, Anoplur. ; Murray, EC.
Ent. 391 ; Schiodte, Ann. N. H. 1866, xvii.
213; M<§gnin, Paras. 74: Piaget, Pedicul
1880.

PELARGO'NIUM. See POLLEN, RA-
PHIDES, and HAIRS.

PELEC'IDA, Vuj.,=Loxodes, Cl. & L.

P. rostrum (PI. 31. fig. 3fy = Lovodes
rostrum.

PELL^E'A, Lk.— A genus of Pterideae
(Polypodiaceous Ferns). Many species,
tropical. (Hooker, Syn. 144.)

PEL'LIA. — A genus of Pellieae (frondose
Hepaticae). P. epiplnjlla (fig. 556) is not
uncommon in damp shady places, by springs
and wells, where it grows rapidly. Its
pedicels are silvery-white, the capsules pale
brown ; and when the valves are fully ex-
panded, the elaters form an elegant tuft
m the middle. The character of the frond
varies somewhat according to the degree of
moisture of the habitat. The forms called
longifolia and furcigera are now considered
to constitute a distinct species, P. calycina.

BIBL. Hooker, Br. Jung. pi. 47 ; Br.

FELLIES,

088 ]

PELONJBA,

Fig. 550.

PelHa epiphylla.
Magnified 2 diameters.

Flora, ii.pt. 1. 130; Endlicher, Gen. Plant.
Supp. i. £s os. 472-5 ; Ekart, Syn. Jung. 63,
pis. 7 & 13 ; Eng. Sot. Supp.j>\. 2873.

PELLIE'^E.— A tribe of Liverworts or
Hepaticae, nearly allied to the Jungerman-
nieae in the character of the fructification,
but having a lobed thalloid frond, traversed
by a mid nerve, from which the fruit-stalks
arise.

British Genera.

Blyttia. Fructification emerging from the
end of the rib below the apex of the frond,
at length dorsal. Perichsete 4-5-parted ;
lobes torn. Perigone herbaceous, tubular,
the mouth denticulated. Archegones eight
to twenty. Epigone persistent, torn at the
summit. Sporange 4-valved. Antheridia
dorsal, placed on the rib, covered by dentate
incumbent leaflets.

Petalopliyllum. Fructification from the
upper surface of the plaited frond. Peri-
chaete broad, bell-shaped and toothed.
Perigone wanting. Epigone concealed in
the perichsete. Sporange bursting into
irregular laciniae. Elaters often branched.

Fossombroma. Fructification emerging
from the end of the rib below the apex of
the frond, at length dorsal. Perichaete
obconic bell-shaped, the mouth crenate or
dentate. Perigone wanting. Archegones
few. Epigone persistent, torn at the sum-

mit. Sporange circumscissile. Anlheridia
dorsal, situated on the rib, naked.

Metzyeria. Fructification emerging from
the ventral side of the midrib of the frond,
Perichaete ventricose, at length bipartite.
Perigone none. Archegones few. Epigone
persistent, torn at the summit. Sporange
four-valved. Antheridia ventral, placed
on the rib, covered by incumbent dentate
leaflets.

Aneura. Fructification emerging from
the ventral side, near the margin of the
frond. Perichaete short, lobed or torn.
Perigone wanting. Archegones few. Epi-
gone persistent, torn at the summit. Spo-
range four-valved. Antheridia immersed
in the back of special lobes of the frond.

Pettia. Fructification emerging from the
dorsal side of the frond. Perichsete short,
somewhat cup-shaped, the mouth lacero-
dentate. Perigone wanting. Archegones
several. Epigone membranous, accompanied
by a few sterile archegones, at first, at the
lower part. Sporange four-valved. An-
theridia immersed in the surface of the
frond.

Blasia. Fructification at first immersed
in the rib of the frond, then emerging from
the apex. Perichaete andperigone wanting.
Epigone membranous, with few sterile
archegones, at first, scattered toward the
lowest part. Sporange four-valved. An-
theridia immersed in the rib of the thallus,
more prominent below, and covered by
little dentate scales.

Taryionia. Fructification sessile, inferior,
solitary and terminal to the frond. Perichaete
two-valved, splitting vertically. Perigoue
wanting. Epigone delicate, persistent, in-
vesting the sporange until maturity, some-
times evanescent above. Sporange bursting
by an irregular slit, or into fragments. An-
theridia immersed in the rib of the frond
below, covered by papillae.

PELOMYX A, Greef .—A genus of Amoe-
baea (Rhizopoda).

This freshwater organism forms large
brown amoeboid masses, with lobose hyaline
pseudopodia. The ground-substance con-
tains nuclei, hyaline homogeneous highly
refractive, and 'delicate rod-like bodies. It
gives rise to swarms of minute Amoebae,
which become developed into flagellate free-
swimming organisms.

BIBL. Greef, Schnitzels Archiv, 1873:
Qu. Mic. Jn. 1874, 97.

PELON^E'A, Forbes.— A genus of Tu-
nicate Molluscs, of the family Pelonaeadae.

PELOPS.

PENICILLIUM.

Char. Unattached ; feet cylindrical ; ori-
fices without rays, on two equal approximate
warty eminences at the anterior end. They
live buried in mud. Two species,:

P. corrugata. Test deep brown, much
elongated, rudely wrinkled transversely.

P. fflabra. Test greenish yellow, smooth,
pilose, shorter than the last. See TUNI- ;

CATA.

BIBL. Forbes and Hanley, Br. Moll. i.
43.

PE'LOPS, Koch (Acarind). — Differs i
from Oribata in the hairs on the vertex |
being flat or spatula-shaped. (Murray, EC. \
Ent. 218 ; Michael, Jn. Mic. Soc. 1879, 237.) I

PELOPSI'NA, Brady. — A genus of Are- |
naceous Foraniinifera, one- or inany-chani-
bered ; walls thick, composed of mud, with
a long chitinous neck. Living, South Seas.
(Brady, Qu. M. Jn. 1870.)

PELTIDE'A, Hofftn., = Species of PEL-
TIGERA and STICTA.

PELTID'IUM = ALTEUTHA.

PELTIG'ERA, Willd. — A genus of
Parmeliaceous Lichens, characterized by a
foliaceous, usually leathery thallus, with
woolly veins beneath; tne suborbicular
shield-like apothecia arising on the upper
sides of the lobules.

P. caninay a large Lichen, is extremely
common on the ground among: moss in
woods. Two or three nearly allied species
are separated from this by most authors,
but with questionable propriety. Three or
four others are subalpine.

BIBL. Hook. Br. Fl. ii. pt. 1. 218 ; Eny.
Bot. 2229 ; Leighton, Lick. Flor. 101.

PENEROP'LIS, Lamk.— A genus of
Porcellaneous Foraniinifera.

Broad, complanate, and ear-shaped (P.
pertusm, PI. 23. fig. 11), or narrow, subcy-
lindric, and crosier-like (Spirolind) (S.
austriaca, PI. 23. fig. 12) ; striated. The
primordial double chamber is succeeded by
curved chambers in one direction; and as
these vary in transverse extent, sometimes
to even three fourths of a circle, the shell
takes different shapes. The aperture is
single and lobulate in the early chambers ;
cribrate in the narrow, branched in the
nautiloid forms (Dendritina) j and divided
into rows of holes, often tubular, in the
outspread varieties. Living in the Medi-
terranean and warm seas only ; fossil in the
Tertiaries.

BIBL. Williamson, Rec. For. 45 ; Parker
and Jones, Ann. N. H. 3. v. 179; Car-
penter, Phil. Tr. 1859, 2 ; Foram. 84.

PENICIL'LIUM, Link.— A genus ofMu-
cedines (Hyphomycetous Fungi), of which
the species P. f/laucum is at once one of the
most frequent and the most puzzling plants
of the class. This fungus is the commonest
of the constituents of the greenish or bluish
mould formed on decaying vegetable sub-
stances of all kinds, especially on semifluid
or liquid matters. On the surface of liquids
it forms a kind of dense pasty crust, slimy
on the lower surface, and coloured and
pulverulent (bearing spores) above. When
the upper fertile layer is examined under
the microscope, it is found to consist of
pedicels terminating in a repeatedly but
shortly bifurcated pencil, eacli ultimate
branch of which bears a moniliforni row of
spores. The ramification of the pedicels is
not distinctly represented in fig. 557 ; but the
appearance of tne spores is characteristic ;
and the ramifications of the sporophores are
scarcely perceptible in examples growing on
dryish substances. The mode of attach inn it
of the spores is shown in figs. 15 and 16 of
PI. 26. The mycelium consists of inter-
woven articulated filaments, most exten-
sively ramified. The spores appear whitish,
yellowish, greenish, or bluish, according to
age : under the microscope they appear
opaque when mature.

So far there is little difficulty about the
history of these plants j and if the spores of
the above form are sown on a glass slide,
kept moist with an organic
liquid, they will germinate
and ramifv, and under fa-
vourable circumstances bear
thin penicillate tufts of spores
at points which emerge from
the nutrient liquid. But
this same fructification of
P. fflaucum presents itself
invariably under certain cir-
cumstances associated with
the vinegar-plant and the
yeast-plant, toward the close
of the ordinary development
of these fungi. In common
with most observers, we find
that the exhaustion of the
saccharine matrix of the
vinegar-plant is followed in
all cases by the appearance
of crusts of Penicillium-
mould on the upper surface,
whence it would appear that
the vinegar-plant was only the mycelium of
Penicillium. It was asserted, moreover,

Fig. 557.

Penicillium.

A fertile plume
with pencils of
spores.

Magnified 150
diameters.

PEN1CILLIUM.

[ 585 ]

PEPPER.

many years ago, by Tin-pin, that P. glaueum
is the last term of the growth both of the
true yeast-plant (Torula Cerevisice) and of
the milk-yeast (Oidium lactis). We have
found the gelatinous crusts of the vinegar-
plant to contain structures which represent
Torula and Oidium, and to grow like them ;
and we have also observed, in repeated ex-
periments, that beer allowed to stand until
sour, at first appears clothed with a whitish
mealy collection of minute vesicles, repre-
senting the ultimate stage of Torula, and
subsequently this gradually gave place to
gelatinous matter, which at length covered
the whole surface with a tough film, and
fruited as Penicillium glaueum. Hence it
would appear that the yeast-fungus also
is merely a vegetative form of Penicillium
developed under peculiar conditions. This,
however, has been actually proved by
Berkeley and Hoffman (see " Yeast," in
Black's { Encyclopedia of Agriculture').
More is said on this point under VINEGAR-
PLANT and YEAST.

One of the species has become famous on
account of its extremely rapid occurrence
in Paris on the upain de munition," where
the spores must have undergone a degree of
heat equal to that of boiling water.

Several species are enumerated j and we
have given under the separate head of
COREMIUM a form which is merely a con-
fluent growth of Penicillium, producing a
compound pedicel.

P. glaueum, Grev. Mycelial filaments
form a crust-like web, spores green or
bluish. Greville, Sc. Crypt. Fl. pi. 58. fig. 1.
P. crustaceum, Fries. Extremely com-
mon.

P. candidum, Link. Mycelial filaments
woven together, spores white. (Distinct ?)

P. sparsum, Grev. Mycelium lax, spores
white. Sc. Crypt. Fl. pi. 58. fig. 2. Per-
haps not different from the last.

P. fasciculatum, Sommer. Mycelium
scarcely developed filaments all fertile,
trifid at the apex, spores glaucescent.

P. subtile, Berk. Extremely minute, my-
celium creeping, fertile filaments erect, sim-
ple or ternate : chains of spores few, spores
broadly elliptical. Ann. N. H. vi. pi. 14.
fig. 25.

P. roseum, Link. Mycelium effused;
fertile filaments slightly branched, spores
rose-colour.

One species (P. curtipes) has been found
in amber.

BIBL. Berk. hook. Br. Flor. ii. pt. 2.

344; Ann. N. H. i. 262, vi. 437, 2. vii. 102;
Greville, loc. cit. ; Fries, Syst. Myc. iii. 407 :
Sum. Veget. 489. See also YEAST and
VINEGAR-PLANT.

PE'NIUM, Breb.— A genus of Desmidi-
acese.

Char. Cells single, entire, elongated,
straight, and slightly or not at all constrict-
ed in the middle.

Sporangia round or quadrangular, smooth,
not spinous.

At each end of the cells is a rounded
space containing moving molecules.

Several British species (Ralfs).

P. Brebissanii (PL 14. fig. 36). Cells
smooth, cylindrical, ends rounded, trans-
verse median band inconspicuous. Length
1-640 to 1-400".

Common. Sporangium at first quadrate,
but finally orbicular j conjugating cells per-
sistent, or remaining permanently attached
to the sporangium.

P. margaritaceum (PI. 14. fig. 37, empty
cell). Cells cylindrical or fusiform, with
rounded truncate ends, and covered with
pearly granules in longitudinal rows. Length
1-160".

BIBL. Ralfs, Desmid. 148; Archer, Qu.
Mic. Jn. 1864, 179, 1867, 183; Hassall,
Alg. ; Rabenh. Alg. iii. 119.

PENNAT'ULA, Cuv. (Sea-pen). — A
genus of Alcyonaria (Zoophytes).

The spicula form interesting microscopic
objects.

PENTHALEUS, Koch. — A genus of
Trombidina (Acarina). Somewhat elon-
gate ; anterior legs rather long and slender ;
femora of hind legs thickened. P.hcematopus.
(Koch, Uebers. ; Murray, EC. Ent. 121.)

PENTHALO'DES, Murr., =Megamerus
ovalis.

PEPLONYS'SUS, Kol. — A genus of
Sarcoptidse (Acarina). 2 species; yellow-
ish-brown ; on Nycteris and Rhinopoma ;
Egypt. (Kolenati, Site. Ak. Wien, 1858,
74 ; Murray, EC. Ent. 323.)

PEPPER.— Black pepper consists of the
berries of Piper nigrum ; white and decor-
ticated pepper of the same berries with the
outer part of the coats removed. The cel-
lular tissues of the several lamellae of the
husk, and of the albumen or body of the
seed, are tolerably characteristic (PI. 2. fig.
12), and may be known by their appearance
under the microscope from the fragments of
linseed, mustard, &c. with which peppers
are sometimes adulterated. White pepper
is fraudulently reduced with flour, which

PERACANTHA.

f 586 ]

PERIGLISHRUS.

may be detected by the starch-granules —
those existing in pepper itself being exceed-
ingly minute particles ; the same remark
applies to rice and pea-flour, &c. Exces-
sive quantities of the husk-tissue in black
pepper denote that the refuse of the decor-
ticated white peppers has been added. (See
also CAYENNE.)

BIBL. Pereira, Mat. Medico, ; Hassall,
Food and its Adulterations, 42.

PERACANTHA, Baird.— A genus of
Entomostraca, of the order Cladocera, and
family Lynceidae.

Char. Side view of shell oval, the lower
and posterior portion with an acute projec-
tion directed backwards and upwards, and,
as well as the upper extremity of the ante-
rior margin, beset with strong hooked
spines ; beak sharp, curved downwards.

P. truncata (PI. 19. fig. 31). Superior an-
tennae conical j inferior short, the anterior
branch with five setae, one from first, one
from second, and three from last joint ; pos-
terior branch with three setae from the last
joint only ; intestine convoluted, with one
turn and a half ; ova two ; freshwater.

BIBL. Baird, Brit. Entom. 136.

PERANE'MA, Duj.— A genus of Flagel-
late Infusoria, family Euglenia.

Char. Form variable, globular, or inflated
posteriorly and narrowed in front, where it
becomes prolonged into a long flagelli-
form filament; movement slow, uniform,
forwards.

P. ylobulosa (PI. 31. fig. 59). Body almost
globular, more or less drawn out anteriorly,
with oblique wrinkles on the surface ;
freshwater; length 1-1400".

BIBL. Dujard. Inf. 353 ; Pritchard, Inf.
545.

PERANE'MA, Don = SpEUEROPTEitis.

PERFORATA, Carpenter. — The Di-
vision of Foraminifera that possess a vitre-
ous or hyaline shell perforated by tubular
openings for the exit of pseudopodia.

BIBL. Carpenter, Introd. Foram. 149.

PERICH^E'NA, Fr.— A genus of Myxo-
mycetes, consisting of little rounded mem-
branous sacs of brownish or yellowish colour,
generally splitting all round (transversely),
and discharging yellow spores and (few)
free and elastic filaments. The commonest
(P. populina), yellowish and about as large
as a mustard-seed, occurs on fallen poplar
trees ; two others occur in fir-plantations.

BIBL. Berkeley, Hook. Br. Fl. ii. pt. 2.
321; Fries, Syst. Myc. 190; Sum. Veget.
459; Greville, Crypt. Flora, 252.

PERICO'NIA, Tode.— A genus of De-
matiei (Hyphomycetous Fungi), character-
ized by a stem composed of fasciculate com-
pacted threads. Head globose ; spores fixed
on the free apices of the threads. It is
analogous to Pachnocybe. Tulasne states
that it is merely a conidiiferous form of
some Sphceria, Two species occur in this
country.

P. glaucocephala, Cd. ; on decayed linen.

P. calicioides, B. ; on dead herbaceous
stems.

BIBL. Fries, Summa Vey. 168; Berk.
& Broome, Ann. N. H. 2. v. 165 ; Tulasne,
Ann. Sc. Nat. 4. v. 109; Cooke, Handb.
565.

PERIDERM. See BARK.

PERIDER'MIUM, Lk. — A genus of
Uredinei (Hypodermous Fungi), distin-
guished from ^ECIDIUM by the sac-like
perithecium bursting irregularly, as if by a
circumscissile dehiscence. The' type of this
genus is P. (jEcid.} Pint, found on the
leaves and bark of Scotch Firs. The spores
are covered with very numerous small
tubercles. See UREDINEI.

BIBL. Berk. Br. Fl. ii. pt. 2. 374; Tu-
lasne, Ann. Sc. Nat. 4 se*r. ii. 176, pi. 10 ;
De Bary, Brandpilze, 1853, 72.

PERIDINI'NA. — An Order of Cilio-
flagellate Infusoria (see p. 422).

PERIDIN'IUM.— A genus of Peridinina
(Cilio-flagellate Infusoria).

Char. Body with a transverse groove, the
two portions of the facetted lorica nearly
equal.

Those species with a horn-like process,
are sometimes separated as Ceratium.

P.fuscum (PL 31. fig. 11). Brown, not
luminous, carapace ovate, slightly com-
pressed, smooth, acute in front, rounded
behind; freshwater; 1. 1-430 to 1-290".

P. (G) tripos (PI. 31. fig. 12). Yellowish,
splendidly phosphorescent ; carapace urceo-
late, broadly concave, mouth with three
horns, two very long, frontal, and recurved,
the third posterior and straight ; marine ;
length 1-140".

Several other species. See GLENODI-
NIUM.

BIBL. Ehr. Inf. 262; Duj. Inf. 374;
Allinan, Micr. Jn. iii. 24 ; Clap, et Lach.
Etudes, 403 ; Clark, Ann. N. H. 1865, xvi.
270 ; Kent, Inf. 447.

PERIGLIS'CHRUS,Koch. SeePTEROP-

TUS.

The species adhere by the margin of the
body all round.

PERTGONIMUS.

PERISPORIUM.

PERIGON'IMUS, Sara.— A genus of
Atractylidae (Hydroid Zoophytes).

Differs from Atractylis in the simple fixed
spore-sacs being rnedusiform.

On other marine zoophytes, shells, &c.

BIBL. St. Wright, Pr. Roy. Soc. Edin. \
1857, 1858; Ann. N. II. 1861, 180; Alder, |
Trans. Tynes. F. C. v. 230 ; Allnian, Ann.
N. H. 1863,1864; Hincks, Hytl Zooph.SQ.

PERI'OLA, Fries.-P. tomentosa, Fr., i
described as a Sclerotioid Fungus, is an j
obscure, irregular, fleshy body, with a white
villous surface, found growing on potatoes.
It is probably the early form of some unas-
certained species of fungus. This was cha-
racteristic of those forms of potato-rot
which were known before the introduction
of the Peronospora.

PERIP'TEBA, Ehr.— A genus of Dia-
toinaceae.

_ Char. Frustules single, compressed; valves
dissimilar, one being simply turgid, the
other winged or furnished with horns ;
horns sometimes branched and attached to
the extreme margin. Fossil.

Valves not areolar nor punctate under
ordinary illumination. America and Ber-
muda.

P. chlamidophora (PL 50. fig. 41) ; P. te-
tracladia (PI. 18. fig. 66) ; P. copra (PI. 18.
fig. 67).

BIBL. Ehrenb. Ber. Berl. Ak. 1844. 263 ;
Kiitz. Sp. Alff. 25.

PERISPIRA, St.— A genus of Holotri-
chous Infusoria. Free, ovate; mouth an-
terior ; oral cilia extending spirally towards
the posterior end.

P. ovum ; green, = Hoplonhnia ovum ?
(Kent, Inf. 611.)

PERlgPORIA'OEL— A family of Asco-
mycetous Fungi, mostly epiphytic and of
small size, characterized by producing floe-
cose common receptacles (mostly) radiating
from a point, forming patches upon leaves,
&c., in the centre of which are developed
somewhat globular perithecia of obscure
cellular structure, persistent, bursting at
the summit, filled densely with subgelatin-
ous, scarcely diffluent gektine ; sporidia
produced in asci, subsequently often effused,
simple, free, and mixed with the gelatine
in the centre of the perithecium. The my-
celia of these plants, bearing conidial struc-
tures, have been described as distinct fungi,
for example those of Erysiphe as Oidia,
&c. See ERYSIPHE. EUBOTIUM probably
belongs here. British Genera :

Lasiobotrys. Perithecium fleshy-horny,

globular, naked, collapsing at the sum-
mit.

Capnodium. Perithecium fleshy, clavate,
double (the outer cellular, interior hya-
line), mucilaginous, opening by a fringed
mouth ; asci containing' about six spores in
two rows.

Erysiphe. Perithecium membranous,
closed at first, afterwards open, supported
on a persistent radiating mycelium formed
of continuous filaments bifid at their ends.
Asci one to eight, paraphyses none ; spores
definite, ovate.

Pensporium. Perithecium superficial,
at length bursting irregularly. Asci club-
shaped, not mixed with paraphyses. Spores
numerous, ovate.

Chcetomium. Perithecium superficial,
finally open at the mouth, clothed externally
with opaque hairs. Asci clavate, mixed with
paraphyses. Spores simple, ovate.

Ascotricha. Perithecium thin, at length
bursting, clothed with dark, subpellucid,
even, obscurely-jointed hairs. Spores sim-
ple, contained in linear asci. Superficial,
at length free or resting on the investing
thallus, black.

Orbtcula, Cooke. Perithecium seated on
a distinct mycelium, reticulated. Ostiolum
obsolete ; sporidia subglobose ; paraphyses
simple or branched.

PERISPO'RIUM, Fr.— A genus of Pe-
risporiacei (Ascomycetous Fungi), consisting
of minute, globular, free, punctiform sacs,
with fleshy or waxy walls, seated on an
obscure thallus, growing on leaves or stalks ;
finally bursting and collapsing. The spores
are produced in large numbers in swollen
clavate asci (fig's. 558, 559), which are un-
accompanied by paraphyses.

Fig. 558.

Fig. 559.

Perisporium disseminatum.

Fig. 558. A perithecium in vertical section. Maeni-
fled 100 diameters.
Fig. 559. An ascus detached. Magnified 300 diams.

BIBL. Fries, Sum. Veg. 404 ; Syst Myc
iii. 248 ; Berk. Ann. N. H. vi. 432.

PERISTEPHANIA.

[ '588 ]

PETALOPUS.

PERISTEPHA'NIA, Ehr.— A genus of
Diatomaceae, closely allied to Stephana-
discus, differing, however, in having a
parallel (and non-radiate) arrangement of
the granules; and also to Systephania,
which differs only in having intramarginal
teeth. P. eutycha in deep Atlantic sound-
ings ; P. lineata in guano.

BIBL. Pritchard, In/us. 824.

PERITHE'CIUM.— The name applied to
the special envelope, mostly of different
structure from the rest of the thallus or the
receptacle, enclosing the nucleus of the
Angiocarpous Lichens and the Pyrenomy-
cetous Fungi.

PERITH'YRA, Ehr.— A doubtful genus
of Diatomacese. Probably closely allied to
Coscinodiscus. 2 species from the Ganges.

BIBL. Pritchard, In/us. 842.

PERITRO'MUS, St.— A doubtful genus
of Infusoria. (Kent, Inf. 759.)

PERIZO'NIUM, Oohn et Jan.— A genus
of Diatomaceae.

Char. Frustules navicular, free, en-
circled with thick linear zones.

P. Braunii (PI. 51. fig. 42), fresh-
water.

BIBL. Rabenh. Alg. i. 228.

PERO'NIUM, Cohn.— A genus of Mona-
dina allied to Anthophysa. It is parasitic
on the spores of Pilularia, and consists of
a delicate, colourless fibre surmounted by a
globular head which resolves into numerous
narrow cells of a monadiform character.

BIBL. Cohn, Entwick. 158 ; Pritchard,
Inf. 501.

PERONOS'PORA, Ung. See BOTRYTIS,
& Smith, M. M. Jn. xvi. 120.

PEROPH'ORA, Wiegm.— A genus of
Tunicate Mollusca, family Clavelinidae.

Char. Individuals stalked, roundish, com-
pressed ; thorax not marked with granular
lines.

P. Listen. Occurs attached to sea- weeds.
Very transparent, appearing like little specks
of jelly dotted with orange and brown.

BIBL. Forbes and Hanley, Br. Moll. i.
28.

PERTUSA'RIA, DC.— A genus of
Lichenaceous Lichens, having an adnate,
uniform thallus, spreading over bark, rocks,
&c., and bearing wart-like apothecia, finally
exhibiting a depressed pore in their centre,
leading to the one or several cells containing
the thecae. P. communis is very common
on trees.

BIBL. Hook. Br. Fl. ii. pt. 1. 164; Engl.
Bot. pi. 677 ; Leighton, Lich. Flora, 226.

PESTALOZ'ZIA, De Not— A genus of
Melanconiei (Stylosporous Fungi), with
septate spores seated on a long pedicel, and
crested at the apex (fig. 711). Three species
occur in this country. P. Guepini is some-
times very destructive to Camellias. They
are beautiful microscopic objects.

See fig. under STYLOSPOKES.

BIBL. Berk. Outl. 324; Cooke, Handb.
471.

PETALOM'ONAS, St.— A genus of Fla-
gellate Infusoria. Free, ovate, depressed,
flagellum single, long, mouth at the ba.se
of the flagellum.

P. abscissa = Cyclidium dbs., Duj.; other
species ; freshwater. (Stein, Inf. iii. : Kent,
Inf. 371.)

PETALONE'MA, Berk. (Arthrosiplum,
Kiitz.). — A genus of Oscillatoriacese (Con-
fervoid Algae), with a remarkable mode of
growth. The filaments are branched and
cylindrical, with an evident terete, gelatinous,
duplicate sheath (PI. 8. fig. 21). The inner
is thin and follows the filament; the outer
presents oblique striae indicating the inter-
position of lengths of the outer sheaths one
inside another, like a series of nested funnels
or conical cups. This appearance is pro-
duced by the bursting and expansion of
each length of the sheath at the apex alone,
to make room for the growth of the new
cells of the filaments formed at the apex.
This structure is analogous to that occurring
in UBOCOCCUS, where each parent-cell
membrane bursts at one side only to allow
the new one to emerge, thus at length
forming a jointed pedicel. The edges of the
funnels of Petalonema sometimes become de-
composed into curled filamentous processes.

The filaments of P. alatum are green and
striated, about 1-3000" in diameter; the
inner sheath is yellowish, the outer colour-
less and 1-400" in diameter. It forms a
brownish stratum on rocks and stones.

BIBL. Berkeley, Gleanings, 23, pi. 7 ;
Greville, Crypl. Fl. pi. 222; Hassall, Fr.
Alg. 237, pi. 68 ; Kiitz. Spec. Alg. 311 ; Tab.
Phyc. ii. 28 ; Al. Braun, Rejuven., Ray Soc.
1853, 178 ; Rabeiih. Alg. ii. 265.

PETALOPHYL'LUM, Wilson.— A ge-
nus of Pellieaa (frondoso Hepaticae). P.
Ralfsii is an elegant little Liverwort with
the* frond plaited or lamellated in rays from
the origin of the fruit.

BIBL. Engl. Bot. Supp. pi. 2874.

PETAL'OPUS, Clap, et Lach.— A genus
of Amoebaea (Rhizopoda). Pseudopodia
filiform, arising from one point of the sur-

PETALOTRICHA.

PEZIZA.

face, but expanding at the end into a delicate
film. The film and pseudopodia become
globular before retraction.

P. diffluent (PI. 52. fig. 16), freshwater.

BIBL. Claparede et Lachmann, Etudes,
442.

PETALOT'RICHA, K— A genus of
marine Peritrichous Infusoria. Free, at-
tached to the base of a horny carapace by
a peduncle j anteriorly a ring of ciliated
petaloid segments. 2 species. (Kent, Inf.
627.)

PETALS.— The petals of Flowering
Plants afford many interesting microscopic
objects, in the epidermis, glandular and
other hairs, the colour-cells, and the veins
composed of spiral vessels. Entire petals
of small size and delicate character form
good objects when dried and mounted in
Canada balsam. Those of the smaller
Caryophyllaceae, the ligulate corollas of
Composite, &c., are well suited for this.
The larger kinds are studied by means of
sections, like LEAVES.

PETROBIA, Murr.,ss?Wfanye&tf8 cris-
fatus.

PETRO'BIUS, Leach.— A genus of In-
sects, of the order Thysanura, and family
Lepismenae.

P. maritimm has a general resemblance
to Lepisma saccharina ; but it exercises a
leaping movement. The antennae are longer
than the body ; of the setae at the tail, the
middle one is longest. The insect is of a
blackish-brown colour, and is covered with
scales ; the legs are yellowish, and the caudal
setae ringed with white ; the abdomen is
furnished will gill-like processes.

It is found upon the rocky sea-coast.

The scales have been used as test-objects.

BIBL. Gervais, Wakkenaer's Apt. iii.
447; Guerin, Iconogr. Ins. pi. 2. fig. Ijf;
and Ann. Sc. Nat. 2 ser. v. 374.

PETRONE'MA, Thwaites.— A genus of
Oscillatoriaceae (Confervoid Algae). P.
fnth'culosa grows as a frustulose olive-
'brown crust on limestone rocks (not marine),
forming little hemispherical masses ; the
sheaths are thick and cartilaginous, brown
above but colourless at the tips, the proto-
plasm dull green.

BIBL. Engl. Bot. Supp. pi. 2959.

PETER'S GLANDS. See INTESTINES
(p. 440).

PEYSSONELIA, Dene.— A genus of
Cryptonemiaceee (Florideous Algae), con-
sisting of small plants with a depressed
lobed tlialliis (fig. 560), growing overstones,

shells, &.c., attached by the whole under
surface, which produces jointed radical hairs
(fig. 561), especially at the thin margins.

Fig. 560.

Thallus. Nat. size.

Fig. 561.

Peyssonelia squamosa.

Vertical section of a portion through two warts.
Magnified 25 diameters.

The thallus is composed of several rows of
compact parenchymatous cells, and bears
on the concentrically-marked surface warts
composed of radiating rows of cells, among
which occur crucially-divided tetraspores.
P. Dubyi is not uncommon on British
shores j it is 1 to 2" in diameter, roundish
at first, ultimately irregularly lobed, and
dull brownish. Thuret has observed an-
theridia on distinct plants of P. squamosa, a
Mediterranean form j they are jointed fila-
ments collected into wart-like bodies, like
those containing the tetraspores.

BIBL. Harvey, Mar. Ala. 144, pi. 14 D;
Phyc. Brit. pi. '71 j Thuret, Ann. Sc. Nat.
4 ser. iii. 23, pi. 4.

PEZI'ZA, Dill.— A genus of HelveUacei
(Ascomycetous Fungi), containing nume-
rous species, a large number of which grow
upon dead wood, on the ground, among
leaves £c., many brightly coloured. They
are at first closed sacs, which burst at the
summit, and spread out to form a kind of
cup containing asci and paraphyses. Thus
they belong to the Discomycetes of some
anthors.

Tulasne has shown that some of the
have a secondary fructification con-

PHACELOMONAS.

[ 590 ]

PHACOPSIS.

sisting of stylospores ; these have been de-
scribed as species of Dacrymyces. Other
species also produce spermatia ; but this was

Fig. 562. Fig. 563. Fig. 564.

Peziza furfuracea. Small variety.
Magnified 5 diameters.

long since suspected by Fries. (See PI. 27.

%• 18.)

BIBL. Berk. Br. Fl ii. pt. 2. 186 ; Fries,
Summa Veg. 348 ; Tulasne, Ann. Sc. Nat.
3 sǤr. xx. 167 ; Currey, Jn. Mic. Sc. v. 124.

PHACELOM'ONAS, Ehr.— A doubtful
genus of Infusoria.

Char. Tail-like process absent; a red
(eye-) spot present ; mouth terminal, trun-
cate, furnished with eight to ten anterior
long cilia or flagelliform filaments, vacuoles
numerous.

P. pulvisculus. Body oblong, subconical,
attenuate posteriorly, bright green; aqua-
tic j length 1-1150". Occurs in myriads in
pools. Perhaps zoospores of (EDOGONIUM.

BIBL. Ehr. Inf. 28 ; Pritch. Inf. 494.

PHACIDIA'OEI.— A family of small
Ascomycetous Fungi, mostly growing in
large numbers on the half-decayed woody
parts of plants, or on the ground ; consist-
ing usually of dark-coloured indurated or
leathery bodies, solitary or connate, or
seated on a common base, closed at first
and containing a soft nucleus; the outer
case (perithecium) subsequently opening
widely, and presenting a cavity lined with
asci containing spores.

The history of development of these plants
is still obscure ; for many of them are con-
nected with certain of the Coniomycetes as
different stages of one and the same plant.
We describe the genera according to the
existing classifications, noting the new facts
relating to these metamorphic phenomena
in the articles on the particular genera.

British Genera.

* Perithecium open, marginal, closed by a
lid or veil.

Patellariq. Perithecium patelliform, mar-
gined, open, covered with a thin veil con-
fluent with the nucleus. Disk at length
pulverulent, the annulate asci breaking out.

Tympanis. Perithecium cue-shaped, mar-
gined, open, covered by a thin, evanescent
j veil. Disk fixed in the receptacle (proper
stratum}, at length dissolved. Asci filiform,
fixed.

| ** Perithecium (exciprulum) at length open,
connate with the Jloccose receptacle.
Nucleus discoid, ascigerous, placed on
the receptacle.

Cenangium. Perithecium entire, leathery-
horny, opening by a connivent mouth, di-
stinct from the discigerous stratum. Asci
filiform, persistent, expelling the separate
spores with violence.

*** Perithecium entire, dehiscing by closely

connivent slits.

Lophium. Perithecium subsessile, elon-
gated, compressed, bursting by a longitudinal
slit. Asci erect, fixed, cylindrical, persistent ;
sporidia simple, rounded. Thallus crus-
taceous or imperceptible.

**** Perithecium someivhat dimidiate, at
length open, nucleus naked.

Rhytisma. Peritheciu m innate, of irregular
form, opening by fragments breaking off
into a tiexuous slit ; nucleus placentiform,
persistent. Asci erect, fixed; paraphyses
stalked.

Phacidium. Perithecium roundish, simple,
bursting with several teeth at the summit ;
nucleus disk-shaped, in some degree per-
sistent. Asci erect, fixod; paraphyses
stalked.

Hysterium. Perithecium sessile, oval or
elongated, with a longitudinal slit at first
closed, afterwards gauing open ; nucleus
linear, somewhat persistent. Asci erect,
fixed; paraphyses stalked.

Labrella. Perithecium innate, bursting by

a longitudinal slit; asci short, broad and

i obtuse above, attenuated below, mixed with

short flexuose paraphyses; spores few, ovate-

1 oblong, occasionally contracted or septate in

the middle.

PHACID'IUM, Fr.— A genus of Phaci-
diacei (Ascomycetous Fungi), containing
many species growing on dead leaves,
branches, &c. Some of them are common,
as P. dentatum, on oak-leaves.

BIBL. Berk. Br. Fl. ii. pt. 2. 291.
t PHACOP'SIS, TuL— A genus of Micro-
lichens, parasitic on the thallus of Evernicc
and Lecanorce.

PHACOTUS.

[ 591 ]

PHIALINA.

BIBL. Lindsay, Brit. Lich. 318 ; Qu. Mic.
Jn. 1869, 143.

PHACOTUS, Perty.— A genus of Cryp-
tomonadina.

Char. Body round, biconvex, with two or
four filaments. Probably it is one of the
Algae.

BIBL. Pritchard, Infns. 513.
PHA'CUS, Nitzsch, Duj.— A genus of
Flagellate Infusoria, family Thecamona-
dina.

Char. Body flattened and leaf -like, usu-
ally green, with an anterior red (eye-) spot,
a single flagelliforni filament, and covered
with a resisting membranous integument,
prolonged posteriorly like a tail. Fresh-
water.

Dujardin distinguishes this genus from
Euglena, by the constancy of the form of
the body, which varies every moment in
the latter genus.

P. pleuronectes (PL 31. fig. 62). Body
oval, almost circular, green, with slightly
marked longitudinal furrows, and a tail-like
prolongation a third or fourth of its length ;
length 1-630".

P. longicaudm (PL 31. figs. 3 & 63). Other
species.

BIBL. Duj. Inf. 334; Archer, Qu. Mic.
Jn. 1871, 99 ;

PH^EOSPO'RE^E, Thuret. See Fu-

ooo
COIBE^5 p. ooo.

PHALANSTE'RIUM, Cienk.— A genus
of Choano-Flagellate Infusoria. Bodies
ovate, flagellum single, with a basal collar ;
imbedded in a simple or branched gelatinous
zoary. Two species ; freshwater. (Cien-
kowski, Arch. mikr. An. iv. 428; Kent,
Inf. 361.)

PHALLOIDE'L— A family of Gastero-
mycetous Fungi, characterized by the pro-
trusion of a large clavate, columnar, stellate
body, or globular, hollow, latticed frame-
work, from the summit of the burst peri-
dium. The basidiospores must be observed
early here, as they fall off and form a deli-
quescent mass upon the hymenium when
the sporauge is mature. The fleshy struc-
ture protruded from the dehiscent capsule
is composed of spherical cells very loosely
connected : the peridium, which is very
tough, is composed of closely packed, very

t slender, filamentous cells.
BIBL. Berkeley, Ann. N. H. iv. 155 ; Br.
Fl. ii. pt. 2. 226 ; Rossmann, Bot. Zeit. xi.
185.

PHARCID'JA, Korb.— A genus of
Micro-lichens found on the apothecia of

Lecanora. Spores 8 ; 2-4-locular, colourless,
linear, or rod-shaped. (Lindsay, Qu. Mic.
Jn. 1869, 343.)

PHASCA'CEJE.— A family of inopercu-
late Acrocarpous (terminal-fruited) Mosses,
minute, gregarious or csespitose, with a
simple or branched stem. Leaves oblong,
oval, lanceolate or spathulate, concave, with
a thick cylindrical nerve ; the cells of the
leaves parenchymatous, looser at the base,
by degrees denser towards the summit,
mostly papillose. Capsules mostly obliquely
apiculate, with spores larger than in most
Mosses, but not so large as in ARCHIDIUM.
Columella soon vanishing in the smaller
species.

British Genera.

Acaidon. Plants very dwarf, gregarious.
Capsule contained in the closed pericheete.
Calyptra mitre-shaped, dimidiate. In-
florescence monoecious (antheridia on a
distinct branch at the base of the stem) : or
dioecious (antheridia terminal on a distinct
plant), bud-like.

Phascum. Plants csespitose. Perichgete
open. Capsule on a longish stalk, and
mostly obliquely apiculate. Calyptra dimi-
diate. Inflorescence monoecious (antheridia
terminal in a bud on a distinct lateral branch,
or naked and axillary on the fruit-bearing
branch), or dioecious.

PHASCO'LON, Stein.— A genus of
Hypotrichous Infusoria. Free, plano-convex,
broadest in front; pharynx enclosing a
rod-fascicle. P. vorticetta ; freshwater ;
length 1-288". (Kent, Inf. 746.)

PHAS'CUM, L.— A genus of Phascacese
(Acrocarpous Mosses), which is now sub-
divided variously by different authors.
Wilson separates the earlier Ph. alterni-
folium only, under the name of Archidium •
foreign authors further distinguish between
PHASCUM, ACATJLON, EPHKMERUM, and
ASTOMUM. Species retained : Ph. crispum,
cuspidatum, curmcollum, rectum, bryoides.
Ph. cuspidatum is very common on banks,
especially on a gravelly soil.

BIBL. Wilson, Bryol Br. 32; Hooker,
Br. Fl ii. pt. 1. 6.

PHIALI'NA, Bory, Ehr.— A genus of
Holotrichous Infusoria, family Trachelina.

Char. Body finely ciliated, having a kind
of neck crowned with large cilia; mouth
lateral, below the appendix to the neck ;
freshwater.

P. viridis (PL 31. fig. 61). Body oval,
nask-shaped, green, suddenly narrowed in

IMIIALONEMA.

r 592

PHLYCT.KXA.

front and gradually behind, neck short
longth 1-290".

P. vermicidaris. White.

BIBL. Ehr. Inf. 333 ; Clap, et Lach. Inf.
304; Kent, Inf. 519.

PHIALONE'MA, Stein.— A genus of
Flagellate Infusoria. Free, flask-shaped,
oral aperture everted, with a single lateral
flagellum. P. cyclostomum, surface spirally
ribbed or striate; freshwater; length 1-500".
(Kent, Inf. 373.)

PHILODI'NA, Ehr.— A genus of Rota-
toria, of the family Philodinaea.

Char. Eyes two, cervical ; tail -like foot
with horn-like lateral processes.

Ehrenberg describes seven species ; fresh-
water ; in general structure and appearance
closely resembling Rotifer.

P. erythrophthalma (PI. 44. fig. 17).
Colourless, smooth, eyes round, processes
of foot short; length 1-120 to 1-50".

P. roseola is reddish, the eyes oval ;
P. collar is has a projecting cervical ring ;
P. citrina has the middle of the body yel-
lowish ; P. macrostyla has oblong eyes, and
the foot-processes very long ; in P. megalo-
trocha the eyes are oval, and the rotatory
organs very large ; and in P. aculeata the
body is covered with soft setaceous pro-
cesses.

BIBL. Ehr. Inf. 498; Pritchard, Inf.
705.

PHILODIN.E'A, Ehr.— A family of
Rotatoria.

Char. No sheath or carapace; rotatory
organs two, simple, resembling two wheels
when the cilia are in motion.

Body usually cylindrical, or somewhat
spindle-shaped, contractile even so as to
form a ball. In certain states of extension
it sometimes appears pointed in front,
from the presence of a proboscis ; in others
the two ciliated rotatory organs are pro-
truded.

The animals are capable of swimming by
means of the cilia, or of creeping like a
leech, the ends of the body being alter-
nately fixed. The tail-like foot is often
furnished with horn-like lateral processes
and terminal toes.

Ehrenberg distinguishes seven genera : —

A. Eyes absent.

a. "Proboscis and horn-like lateral pro- \ fallidina

cess on the foot present f

|3. Proboscis and horn-like processes )

absent J

a . Rotary organ stalked Hydrtas.

6. Eotary organ not stalked Typhlina .

B. Eyes present.

Eyes two, frontal.

Foot with horn-like processes.

Toes two Eolifer.

Toes three Actmv.ru*.

Foot without horn-like proces- ) -M-nnnlnhi*

ses, but with two toes... \M

Eyes two, cervical Phtiodina.

BIBL. Ehrenberg, Infus. p. 481.

PHILOME'DES, Lilljeborg.— A Cypri-
dinad, witli suboval valves, notched in front,
spined behind, punctate. Upper antennas
6-jointed, longer in the male : natatory
branch of lower antennae 9-jointed, secon-
dary branch setose in the female, cheliform
in the male. Eyes small and pale in female,
large and red in male. 1 British species,
rare.

BIBL. Brady, Linn. Tr. xxvi. 377; Pr.
Zool. Soc. 1871, 291.

PHILOP'TERUS, Nitzsch.— A genus of
Anoplurous Insects, of the family Philo-
pteridae.

Char. Antennae filiform, five-jointed;
maxillary palpi none; mouth with strong
toothed mandibles ; tarsi with two claws.

The species are yeiy numerous, and have
been arranged in six subgenera : Docopho-
rus, Nirmus; Goniocotes, Goniodes, Lipeurus,
and Ch-nithobius. In some of them there are
two movable organs (trabeculse) situated
in front of the antennae.

P. (Docophorus) communis (PI. 35. fig. 5).
Chestnut- coloured, shining, with white
hairs ; head triangular, elongate, anterior
portion much produced; trabeculae very
large, curved ; posterior femora much incras-
sated and toothed below. Length 1-16".

Parasitic upon the Passeres or Insessores.

BIBL. Denny, Anoplur. Monoyr. (Y2.

PHLE'BIA* Fr.— A genus of Hymeno-
mycetous Fungi, intermediate between
Hydnei and Auricularini. The hymenium
is soft and pinched up into crest-like
wrinkles or veins, which do not form di-
stinct pores. Four species are found in this
country, of which two at least are very
pretty when in perfection.

BIBL. Frtyrf.lfyc.i420; Grev.t.280;
Hass. ii. t. 44; Berk. Outl. 263; Cooke,
Handb. 305.

PHLOEM.— The liber-portion of the
fibro-vascular bundles of stems.

PHLYCT^E'NA, Desmaz.— A genus of
SphaBronemei (Stylosporous Fungi), nearly
related to Septoria, differing in the absence
of a proper peritheciurn. P. vayabunda has
been found in Britain.

BIBL. Berk, and Broome, Ann. N. II. '2.

PHLYCT^ENIA.

[ 593 ]

PHOTOGRAPHY.

xiii. 460; Desmazieres, Ann. Sc. Nat. 3.
viii. 16.

PHLYCT^'NIA, Kg.— A genus of Dia-
tomaceae.

Char. Frustules those of Navicida, en-
closed in gelatinous globular cells (masses?).
Marine.

P. minuta. Cells 1-720 to 1-240" in dia-
meter ; length of frustules 1-1200 to 1-600".

P. maritima (Frustulia mar., E.).

BIBL. Kiitzing, /Sjy. Alg. 96 ; Ehrenberg,
Infus. 232.

PHLYCTID'ICJM, Br.— A genus of Uni-
cellular Algae, allied to Chytridium-, con-
sisting of globose or oblong inoperculate
cells, the orifice simple or slightly produced,
either rooted or not ; gonidia with a single
long cilium. Several species; in fresh-
water Algae, &c. (Rabenhorst, Fl. Alg.
iii. 278.)

PHLYC'TIS, Wallr— A genus of Pertu-
sariei (Lichenaceous Lichens). 2 species,
on trees, frequent. (Leighton, Lichen Flora,
237.)

PHO'MA, Fr. — A genus of Sphaeronemei
(Stylosporous Fungi). There are nume-
rous British species, forming small black or
brown pustules upon dead leaves, twigs, &c.
Tulasne regards this genus as formed by
pycnidiiferous states of SPH^RIA. P. uvicola
produces the disease called Anthracose on
the vine.

BIBL. Berk. Br. Fl. ii. pt. 2. 285 ; Ann.
N. H. vi. 263 ; 2. v. 368, xiii. 459 ; Fries,
Summa Veg, 421 ; Tulasne, Ann. Sc. Nat.
4. v. 115 ; Cornu, G-revittea, vii. 18.

PHO'NOLITE. See ROCKS.

PHORMID'IUM, Kiitz.— An obscure
genus of Oscillatoriaceae, the filaments
sheathed, forming a membranous layer;
many species. (Rabenhorst, Fl. Alg. ii.
115.)

PHOR'MIUM, Forst.— P. tenax is the
name of the plant yielding New-Zealand
Flax. It is a Monocotyledonous Flowering
Plant belonging to the order Liliaceae.

PHOR'ODON, Pass.— A gen us of Aphidae.
Two species ; on the hop (Aphis humuli),
the sloe, and the plum. (Buckton, Aphides,
Ray Soc., i. 165.)

PHOSPHORESCENCE and PHOTO-
GENIC STRUCTURES, see Micr. Diet.
3rd edition, 504 ; and the Bibl. therein.

PHOTOG'RAPHY.— Microscopic ob-
jects may be photographed by the ordinary
methods, especially by the collodion pro-
cess, by arranging the microscope so as to
form the optical part of a camera obscura.

The old solar microscopes are examples of
the principle of such an arrangement. Mi-
croscopic cameras have been constructed in
which the lens is replaced by a fitting
carrying achromatic object-glasses, with
the rod bearing the stage and illuminating
apparatus, as in the ordinary stands of com-
pound microscopes. A simpler plan for
those who possess a compound instrument
and a camera, is to remove the lens of the
latter and introduce into its place the eye-
end (with the eyepiece removed) of the
compound body, placed in a horizontal posi-
tion ; filling up the crevice all round with
a piece of black velvet or cloth. Another
method (Wenham's) which dispenses with
the camera, is to operate in a room darkened
by a shutter having an orifice through
which the sunlight may be reflected by a
mirror placed outside, and received either
directly or condensed by a bull's-eye, on the
object lying on the stage of the microscope
placed horizontally, with the eyepiece re-
moved ; a screen placed at a suitable dis-
tance from the eye-end of the tube receives
the image. In operating with this screen,
the object should be focused on a sheet of
card, and then, the light being shut off by
covering the eye-end of the tube, a prepared
paper or collodion plate be substituted ex-
actly in the same place. Means must be
used, by a black cloth or similar contrivance,
to shut off all side light between the orifice
of the shutter and the object-glass. In
this last process, it is possible to obtain
pictures with different parts of the object
not lying in the same plane, by separate
focusing, applying pieces of card suitably
cut to shut off the image at different parts
as required. With very minute objects and
high powers, the achromatic condenser is
used, as well as the bull's-eye.

It is well known that the correction of
the objectives for perfect vision is not the
best for photographic purposes. With high
powers, as the 1-4" object-glass and upwards,
the difference may be neglected, but with
lower powers, an adjustment is required.
Shadbolt finds it sufficient to withdraw the
object-glass a little by the fine movement,
from the object, and gives the following
data for Smith and Beck's object-glass : for
the 4-10", withdraw the objective 1-1000";
for the 2-3", withdraw it 1-200"; for the
If", withdraw it 1-150". Wenham pre-
fers to place a doubly convex lens in the
place of the back stop of the object-glass,
and advises for the 4-10" and 2-3" object-

2Q

PHRAGMICOMA.

[ 594 ]

PHTHIRITJS.

glasses a lens of 5" focus ; for the 1£" a lens
of 8" focus.

Microscopic photographs are best obtained
with solar light ; but artificial light has been
used, as that from camphene or gas for low
powers, the oxyhydrogen light for high
powers, andMaddox has used the magnesium
light. A great point is to secure clean pre-
parations, with the object sufficiently flat to
allow of being clearly focused all over ; this
sets a limit to the utility of the process ;
further, certain objects in which red and
yellow, or yellowish-brown colours exist, do
not transmit the light, or only imperfectly.
It will probably be advantageous to bleach
many objects, as, for instance, insects and
their parts, by long maceration in turpen-
tine, sections of dark-coloured wood by
nitric acid, &c., when they are intended to
be photographed.

The purely photographic manipulation
cannot be given here, but requires the ordi-
nary skill in photography. Lengthened
particulars respecting the application of
photography to the microscope are contained
in the papers referred to below.

BIBL. Highley, Qu. Mic. Jn. i. 178, 305,
and ii. 158 ; Shadbolt, Qu. Mic. Jn. ii. 165;
Wenham, Mic. Tr. 1855, 2. iii. 1 ; Rood,
Qu. Mic. Jn. 1862, 261 ; Hessling and Koll-
mann, Atlas, d. thier. Geweb. 1862 ; Maddox,
Tr. Mic. Soc. 1863, 9 ; ibid. 1865, 34 ; Jn.
Lond. Photo. Soc. 1864 ; Mn. Mic. Jn. 1869,
27 ; Woodward, ibid. 29, vol. iii. 290; Qii.
Mic. Jn. 1870, 380 ; Brit. Jn. Photo. 1866 ;
Moitessier, Photog. Appliquee, 1866; Reich-
ardt and Sturenburg, 1868, Mon.mik. Phot.;
Benecke, Photogr. 1869 ; Hermann, Phot. ;
Gayer, Micro-photogr. ; M. M. Jn. xv. 258 ;
Frey, Das Mik. ; Beale, How $c., and the
notices therein.

PHRAGMIC'OMA, Dumort.— A genus
of Jungermannieae (Hepaticae), containing
one British species, P. Mackaii (Jung.
Mackaii, Hook.), occurring
rarely on trees and rocks, espe-
cially on limestone.

BIBL. Hook. Br. Jung. 63 ;
Ekart, Syn. Jung. 59, pi. 9.
fig. 72 ; Endlicher, Gen. Plant.
Suppl. i. 472-9.

PHRAGMIDTUM, Lk.
(Aregma, Fr.). — A genus of
Uredinei (Ooniomycetous
Fungi), forming rusts very i80iated basi-
common on Rosaceous plants. <*ium with four
*ey appear upon living jgfcJBSL
leaves, breaking through from

Fig. 565.

Phragmidium
bulbosum.

beneath the epidermis, and are chiefly dis-
tinguished from PUCCINIA by the number
of septa which are contained in the spores
or pseudospores. P. bulbosum is common,
forming yellow and brown pulverulent
spots on bramble-leaves (see AREGMA).

BIBL. Berk. (Areffma), JBr. Fl. ii. pt. 2.
358 ; Grev. Sc. Crypt. Flor. pi. 15 ; Tulasne,
Ann. Sc. Nat. 4 s«5r. ii. 180, pi. 9 ; De Bary,
Brandpilze, 1853, 49, pi. 4 ; Fries, Sum. Veg.
507 ; Currey, Q. J. Micr. Sc. v. 117.

PHRAGMOTRICH A 'CE^E.— A family
of Coniomycetes, distinguished from Melan-
coniei by their moniliform chains of spores.
See CONIOMYCETES.

PHRAGMOT'RICHUM, Kze.— A genus

Fig. 566.

i

Fig. 567.

Fig. 568.

Phragmotrichum Chailletii.

Fig. 566. Scale of a spruce-fir cone, with pustules.

Half nat. size.

Fig. 567. A pustule, magnified ]0 diameters.
Fig. 568. Vertical section across a pustule, showing

the chains of spores. Magnified 100 di

of Phragmotrichacese (Stylosporous Fungi).
The plants form little tubercles bin-sling
out from beneath the epidermis, and con-
taining filaments arising from a softish
fibrous stroma. The filaments (basidia)
are interrupted at intervals with cellular
spores (fig. 568), which ultimately separate.
P. Chailletii grows upon the scales of the
cones of Abies exceha. Other species grow
on the poplar and maple.

BIBL. Fries, Syst. Myc. iii. 492; Sum.
Veg. 474 ; Berk. Crypt. Sot. 327.

PHTHIR'IUS, Leach.— A genus of
Anoplura, family Pediculidae.

Char. Legs of two kinds, anterior pair
formed for walking, posterior pairs for
climbing ; thorax large, not distinctly sepa-
rated from the abdomen.

PHYCOMYCES.

[ 595 ]

PHYLLOPHORA.

P. inguinalis (Pediculus pubis). Parasitic
upon man. Length 1-10 to 1-20".

The ova are firmly fastened to the hairs
by a glutinous secretion ; they are urn-
shaped, and furnished with a lid.

BIBL. Denny, Mon. Anopl. 8; Leach,
Zool, Misc. iii. Go ; Megnin, Paras. 75.

PHYCOMY'CES, Kze.— A genus of
Mucoiini (Phycomycetous Fungi), of which
one species, P. nitens, has been found in
Britain growing on the walls of oil-cellars
and on grease. It is olive-coloured, dis-
tinguished from Mucor chiefly by the absence
of a columeila, the pyriform peridiole, and
oblong spores-; but the entire plants are
much larger and of more solid texture.
The fertile filaments of P. splendens, the
only other known species, are as thick as a
horse-hair, and 3 to 4" high.

It is the finest of all the Mucorini, and
was at first considered an Alga, which it
strongly resembles on a superficial exami-
nation, when dry, from its green shining
threads.

Van Tieghem attributes to this a fructi-
fication like that of Syzygites, with which
genus it must ultimately be combined.

BIBL. Fries, Syst. Myc. iii. 3C9 ; Sum.
Veg. 488 ; Berk. Ann. N. H. vi. 433 ; Van
Tieghem, Ann. Sc. Nat. 1873, xvii. 292.

PHYCOMYCE'TES.— An order of Fungi
composed of microscopic plants of very
simple organization, the mycelium being a
by&soid or flocculent mass, bearing simple
vesicular sporanges (peridiola), filled with
minute spores. The nature of the mem-
branous wall of the peridioles is not yet well
ascertained in all the genera, some authors
describing it as merely a veil, others as a
perfect sac formed by the expansion of the
terminal cell of the filament, which is cer-
tainly true in Mucor. According to our
own observations, the spores are formed by
free-cell formation in the peridiole, which
ultimately bursts to discharge the spores.

But the division Antennariei cannot stand ;
AKTENNABIA seems to be merely a form of
CAPNODirM ; and PISOMYXA and PLEURO-
PYXIS are obscure objects of which little is
known.

In the Antennariei the peridioles are ses-
sile on radiating flocci, which sometimes
send processes which grow up and surround
them, or they are attached to the sides of
eiect filaments; these filaments form whitish
or greyish patches, on the leaves of trees
and herbs, bearing a close external resem-
blance to Erysiphe.

The Mucoiini are moulds growing on
decaying organic matter, the mycelium
constituting flocks floating in liquids or
overgrowing damp substances, while the
delicate spore-sacs or peridioles are borne
at the apices of erect stalk-like and often
extremely branched filaments. The genus
Syzyyites exhibits a remarkable peculiarity.
Each spore-sac is formed by means of the
conjugation of two branches of the ramified
fructification (see SYZYGITES).

The later researches on the plants of this
group seem to indicate that, as in most of
the Fungal Orders, much remains to be
cleared up concerning the relations of the
forms. See on this subject the article Eu-
POTITJM, which genus, according to De
Bary's researches, is associated as merely a
second form of fructification, with ASPER-
GILLUS, upon the same mycelium.

PH YL ACTEL 'LA, Hincks, = Lepralia
pt. (Hincks, Polyz. 356.)

PHYLLODE'L— A series of Lichena-
ceous Lichens.

Char. Thallusfoliaceous, depressed, lobed.

BIBL. Leighton, Brit. Lich. Flora, p. 2.

PHYLLOGONIA'CE^E.— A family of
Pleurocarpous Mosses, distinguished by the
peculiar character of the leaves and their
arrangement. The leaves are either in-/
serted horizontally or imbricated vertically,
clasping, and are composed of very narrow
linear parenchymatous cells, appearing
almost confluent into a homogeneous mem-
brane, auricled at the base, with minute,
parenchymatous, thickened alar cells ar-
ranged orbicularly at the auricles, very
smooth j the leaves stand in two opposite
rows.

This family contains only the single small
exotic genus Phyllogonimn.

PHYLLOM'ITUS, Stein.— A genus of
Flagellate Infusoria. Free, ovate ; flagella
two, unequal, united at the basal portion ;
no mouth. P. undulans, freshwater. (Kent,
Inf. 299.)

PHYLLOPH'ORA, Grev.— A genus of
Cryptonemiaceas (Florideous Algas), con-
sisting of several species, with a red, rigidly
membranous, stalked, leaf-like, often dicho-
tomous thallus, the lobes of which are often
proliferous ; from a few inches to a foot long,
growing near low-water mark, or in the sea.
(P. rubens, PI. 4. fig. 4.)

The fructification consists of: — 1. favelli-

dia, scattered over the thallus, containing

minute spores ; 2. antheridia, wart-like

bodies composed of radiating moniliform

2Q 2

PHYLLOPODA.

[ 696 ]

PHYSIOTIUM.

filaments found on distinct plants from the
spores; and 3. tetraspores, collected into
sori either towards the apex of the thallus
or on proper lobes.

BIBL. Harvey, Mar. Alg. 142, pi. 18 A ;

Phyc. Brit, pi." 191 ; Greville, Alg. Brit.

pi. 15 ; Derbes and Solier, Ann. Sc. Nat. 3

se"r. xiv. 277, pi. 37 ; Thuret, ibid. 4 se"r. iii. 18.

PHYLLOP'ODA. See ENTOMOSTKACA.

PHYLLOXE'RA, Fonsc.— A genus of

Aphidae (Homonterous Hemiptera) ; the

species have the fore wings flat on the back,

with 1 simple stigmal, and 2 simple oblique

discoidal nerves ; the antennae 3-jointed.

These insects are notable from the immense
damage they do, in the vinicolous countries,
to the grape-vines. The apterous broods
feed upon the roots of the vine, exhausting
its juices, producing decay of the leaves, and
absence of fruit. In the autumn, the winged
sexual forms are produced, which spread the
malady abroad, by laying their eggs in new
places. P. vastatrix (PI. 53. fig. 7) is the
vine-pest ; but other species occur on the
oak, &c. The insects may be found by
separating the layers of the roots, and
examining them with a good lens, when
they will be seen in all stages, often sur-
rounded with a zone of eggs.

BIBL. West wood, Intr. ii. ; Fatio and
Demole-Ador, Rap. s. 1. Phyll. 1875-76;
Lichtenstein, Ann. Agronom. 1876, ii. 129 ;
Robin, Micr. 1877, 953; Balbiani, Rev.
Scient. 1874; Cornu, Phyll. vast., 1878
(24 plates).

PHYMATOP'SIS, Tul. — A genus of
Microlichens parasitic on the apothecia
and thallus of Usneae.

BIBL. Lindsay, New-Zealand Lich. and
Fungi, 442 ; Qu. Mic. Jn. 1869, 350.

PHYSAC'TIS, Kiitz.— A genus of Oscil-
latoriaceae (Confervoid Algae), improperly
separated from Rivularia, consisting of
freshwater and marine plants, growing on
stones &c., at first globose, and afterwards
vesicular and lobed by peripheral growth
accompanied by gradual decay of the ori-
ginally solid centre. Under this head are
included : —

P. (Rivularia) nitida. Deep olive-green,
tufted and lobed, gregarious ; fronds from
1-12 to 1" in diameter. (R. bullata, Berk.)
Marine,

P. (Riv.) plicata. Diam. 1-12 to 1-2" in
diameter ; deep green. Marine.

P. (Riv.) pwum. Globose, dirty green,
1-12 to 1-2" in diameter. Freshwater.

BIBL. Ktitz. Sp. Ala. 332; Tab. Phyc.

Bd. i. pi. 58; Hassall, Fr. Alg. 262 ; Har-
vey, Mar. Alg. 222 ; Berk. Gleanings, pi. 2.
fig. 1 ; Rabenh. Alg. ii. 206.

PHYSA'RUM, Pers.— A genus of Myxo-
mycetes, containing numerous species
growing on rotten wood, bark, leaves, &c.
They are nearly related to Didymium and
Didcrma, but liave a simple membranous
peridium : the filaments are adnate to the
peridium; but in some spores they are
very few, approaching to the condition of
Licea. Some are sessile, others stipitate
(fig. 569) ; the clustered forms (P. hi/ali-

Fig. 571. Fig

Fig. 670.

Physarum bryophilmn.

Fig. 569. Plants growing on a Plagiochila. Magn. 2
diams.

Fig. 570. A peridium burst. Magn. 25 diams.

Fig. 571. Filaments and spores from the same. Magn.
100 diams.

num and utriculatuni) are removed to
Berkeley's genus BADHAMIA. P. album is
common.

BIBL. Berk. Br. Fl. ii. pt. 2. 314 ; Mag.
Zool. and Bot. i. 49 ; Ann. N. H. vi. 431,
2. xiii. 159 ; Fries, System. Myc. iii. 127 ;
Sum. Veg. 153 ; Greville, Crypt. Fl. pi. 40.
310; Cooke, Grevilka, 1880; Kent, Pop.
Sc. Rev. 1881, and Inf. 470.

PHYS'CIA, Nyl.— Like Parmelia, but
with the spores bilocular ; many species.

PHYSCOMIT'RIUM, Bridel.— A rams
of Funariaceae (Acrocarpous Mosses;, in-
cluding many Gymnostoma of other authors.
P/iyscomitrium pyriforme, Brid.= 6r?/»/fto-
stomum pyriforme, Hedw. Ph. spharicum
is remarkable as having been found only in
one year in one locality in Britain.

This species exhibits a pretty structure in
a vertical section of the immature capsule,
the mass of sppriferous tissue being sus-
pended freely in the middle by cellular
threads.

PHYSIO'TIUM, Nees.— A genus of Juu-
germannieae (Hepaticae), containing one

PHYSODICTYON,

[ 597 ]

PILOBOLUS,

species, P. cochleariforme, a large plant,
growing- in purple tufts 4 to 6" long, on
moors and among rocks in Ireland and the
Scotch highlands.

BIBL. Hook. Brit. Flor. ii. pt. 1. p. 119;
Br. Jung. p. 68 ; Engl. Bot. pi. 2500 ; Ekart,
Synops. Jung. pi. 5. fig. 40 ; Endlicher, Gen.
Plant. Suppl. 1. nos. 472-81.

PHYSODICTYON, Ktz.— A genus of
Algae, consisting of globular vesicles com-
posed of angular parenchymatous cells con-
taining chlorophyll; diameter 1-12". On
rocks and submerged wood. P. graniforme
(PI. 3, fig. 14). (Rabenhorst, Alg. iii. 312.)
PHYSOM'ONAS, Kt.— A genus of Fla-
gellate Infusoria. Rounded, free or fixed by
a slender filament; obliquely truncate in
front; flagella two, unequal ; diam. 1-3000";
freshwater and marine. (Kent, Inf. 263.)

PHYTEL'EPHAS, R. and P.— The ge-
neric name of the Palm yielding the VEGE-
TABLE-IVORY nut.

PHYTOCRE'NE, Wallich.— An Arto-
carpaceous tree with wood of very remark-
able structure. See WOOD.

PHYTOP'TID^E.— A family of Acarina,
the nature of which is ill-understood. The
members are found in the buds and galls of
plants. The galls, which form warts, tu-
bercles, nail-like growths &c. upon the
leaves, and produce distortion of the buds,
were formerly considered fungi, and placed
in the genera Erineum, Phitterium, &c. The
Acari are usually elongate, the body trans-
versely striated, the legs two anterior pairs,
the hinder pairs being replaced by tubercles
or long hairs. They were supposed to be
the larv£e of Tetranychus or other Acarina,
but their eggs are found with them in the
galls. They have not been properly ar-
ranged in genera and species, being usually
referred to the single genus Phytoptus, Duj .
They are often very transparent and easily
overlooked, and sometimes can only be
found by washing the opened galls, and
searching for them in the wash-water.
They are commonly met with in the galls
of the lime, the vine, the willow, the pear,
yew, &c., and are named accordingly P.
tilue (PI. 53. fig. 24), P. vitis, &c.

BIBL. Dujardin, Ann. Sc. Nat. 1857, iii.
15 j Pagenstecher, Verh. Heidelb. 1859;
Frauenfeld, Verh. zool.-bot. Ges. Wien, 1864-
72; Low, ib. 1874; Thomas, Zeitschr. ge-
sammt. Natumv. xxxiii. ; Kaltenbach,
Pjftanz.feinde ; Briosi, M. M. Jn. xvii. 181
(with copious Bibl.); Ormerod, Inj. Ins.
179 ; Murray, EC. Ent. 365.

j ^ PICO'BIA, Hall.— A genus of Trombi-
I dina (Acarina). P. Heeri, in the subcu-
taneous cellular tissue of the woodpecker.

BIBL. Meg-urn, Paras. 248; Haller,
Zeitschr. wiss. Zool. 1877, xxx.

PIGGO'TIA, Berk, and Broome.— A
genus of Sphaeronemei (Stylosporous
Fungi), or perhaps the conidiiferous form of
Dothidea. P. astroidea occurs on the green
leaves of the elm, forming irregular round-
ish, granulated or wrinkled jet-black patches
(sometimes with a yellow border) on the
upper surface of the leaf. Perithecia soon
confluent, bursting by a lacerated fissure.

BIBL. Berk, and Broome, Ann. N. H. 2.
vii. 95, pi. 5. fig. 1.

PIGMENT. See INTRODUCTION, p. xxxiv.
PIGMENT-CELLS of connective tissue
occur in a few isolated spots only in Man
and the higher Vertebrata, but are widely
distributed in Amphibia and Fishes, appear-
ing especially in the skin, the serous mem-
branes, and the tunica adventitia of the
vessels. The pigment is deposited in gra-
nules, which differ in shape and colour.
The pigment-cells of connective tissue are
usually characterized by their beautiful
stellate form and numerous processes. In
Man they occur normally in the eye. The
pigment-granules in Amphibia are collected
in round masses or diffused in the stellate
cells, their movement being evident but
slow. Spontaneous alteration in form of
pigment-cells occurs in the skin of these
animals, and is connected with the change in
colour which they present. See MEL ANINE.
PILA'CRE, Fr.— A genus of Trichogas-
tres (Gasteromycetous Fungi).

This genus must not be confounded with
Onygena, to which it bears a certain resem-
blance. One or two of the species are
remarkable for the strong permanent odour,
resembling that of pigs.

BIBL. Berk, and Broome, Ann. N. H. 2.
v. 365, pi. 11.

PILEOLA'RIA, Cast. See UROMYCES.
PILEORHTZA.— A conical hood on, or
shield or guard to, the tips of the roots of
plants, protecting the nascent tissue. See
ROOT.

PILIN'IA, Kiitz.— A genus of Cheeto-
phoraceous Algae . Filaments erect, j ointed,
tufted, rooting, forming a spongy stratum.
P. rimosa (PI. 3, fig. 15), on submersed
wood ; marine. (Rabenhorst, Alg. iii. 386.)
PILOBO'LUS, Tode.— A genus of Mu-
corini (Phycomycetous Fungi), consisting
of little moulds growing upon dung ; bear-

PILOPHOPtON.

[ 598 ]

PILULAPJA.

ing some resemblance in their structure to
Botrydium among the Algae. The plants
have a stoloniferous creeping mycelium,
from which arise fertile pedicels, each cut
off from the mycelium by a septum ; the
upper part of the pedicel expands into the
•vesicle, which also becomes shut oft' by a
septum ; in the vesicle or peridiole, spores
are next developed by free-cell formation,
and at the same time the septum becomes
pushed up into its interior (as in Mucon)
to form a columella, which ultimately causes
the vesicular peridiole to split off by a cir-.
cumscissile dehiscence just above the sep-
tum ; it is thrown off with elasticity, en-
closing the spores. The development of
P. crystallinus has been studied by Cohn and
Bail. They find the germinating spore to
produce a creeping unicellular mycelial por-
tion, and next a fruit-pedicel, which soon
has the peridiole separated by a septum ;
thus, in its simplest form, this plant consists
of only three cells; subsequently it becomes
complex by the root-cell or mycelium pro-
ducing numerous stolons. P. crysUUKniu is
yellowish at first, the peridiole finally black.
P. roridus, Bolt., a doubtful species, is smaller
and more slender than the last, having an
elongated filiform stem.

BIBL. Berk. Br. Fl. ii. pt. 2. 231 ; Fries,
Sum. Veget. 487; Cohn, Nova Ada, xxiii.
492 ; Bail, Bot, Zeit. xiii. 630 ; Currey, J.
Linn. Soc. Botany, i. 162.

PILOPH'ORON,Tuck.— A genus of Cla-
doniei (Lichenaceous Lichens). P. Jibula,
on wet rocks, rare. (Leigh ton, Lick. Fl. 69. )
PILOT'RICHUM, Pal. de Beauv.— A
genus of Hypnoid Mosses, including some
Fontinales of authors.

Pilotrichum antipyreticum, C. Miill.=
Fontinalis antipyretica, L.

P. squamosum, C. Mull. = /"'. squamosa,
L.

P. ciliatum, C. Mull. = Anccctangium cilia-
turn, Brid., Tar. y. striatum=A. ciliatum,
Wilson.

P. heteromattum, P. d. ^.—Daltoniahete-
romatta, H. and T.

PILULA'RIA, L.— A genus of Marsile-
aceous Plants, containing the only British
representative of the order — P. globuUfera
(fig. 574). This is an inconspicuous plant
growing in mud at the edges of or in pools,
having a filiform creeping stem, bearing
erect filiform green leaves and delicate ad-
ventitious roots, and producing shortly-
stalked globular spore-fruits, about the size
of a pepper-corn. The anatomical structure

of the stem and leaves is simple : they are
clothed with an epidermis possessing sto-
mata ; and a cross section both of the stem
and the leaves exhibits a central vascular
bundle (of spiral vessels) surrounded \\\ a
bheath of brownish cells, while in the deli-
cate cellular tissue intervening between the
central bundle and the epidermis stands a
circle of air-passages separated from each
other by simple raoiaticg cellular septa.

Fig. 572.

Fig. 573.

Pilularia globulifera.

Fig. 572. A vertical section of a spore-fruit. Mncn
5 diameters.

Fig. 573. Transverse section of a spore-fruit. Maen.
5 diameters.

The spore-fruits are hollow cases with an
outer tough cellular coat, and an inner more
delicate coat dippinginat four perpendicular
lines, as far as the centre, so as to form
dissepiments dividing the fruit into four
chambers (figs. 572, 573) ; up the centre of
the outer wall of each chamber runs a raised
ridge, a kind of placenta, whence arise the
sporanges or theca (tig. 673). These are
pear-shaped sacs composed of a very deli-
cate cellular membrane. Those in the upper
part of each chamber contain a number of
minute globular bodies (microspores), re-
sembling pollen-grains, immersed in a gela-
tinous liquid. The sacs in the lower part
of the chamber contain only one body or
spore (rnacrospore) of very peculiar form ;
it nearly fills the theca, is somewhat oval,
and possesses several coats.

In the development of the spores the
small spores are developed in the usual way,
by the formation of parent cells in the
theca, each subsequently producing four
spores. In the thecae which have the sino-le
large spore, a number of parent cells are
originally produced; and these become
divided into four chambers by septa ; but
then all but one of these decay. This pro-
duces four spores; but out of these four,
only one attains perfect development, the
rest being subsequently dissolved and ab-
sorbed to make room for the solitary large
spore. The two kinds of spore in Pihdaria

PILULARIA.

[ 509 ]

PILULARIA.

correspond to the two forms in SELAGI-
NELLA and ISOETES, and to the pollen and
ovules of the Flowering Plants. They are
set free by the dehiscence of the spore-fruit,
and lie at tirst imbedded in the jelly poured
out by the thecae.

In this state the small spores resemble
pollen-grains, having an outer granular, and
an inner delicately membranous coat, — the
outer coat presenting ridges corresponding
to the points of contact in the parent cell.
When set free, the spores soon burst at
these ridges, and the inner coat is slightly
protruded ; this next bursts and discharges
a number of lenticular cells, from each of
which escapes a ciliated spiral spermatozoid.

The mature large spores (fig. 575) are of

Fig. 574.

oval form, and have a thick outer gelati-
nous coat composed of prismatic cells stand-
ing perpendicularly on an inner glassy coat ;
the gelatinous coat is perforated at the
summit by a funnel-shaped opening through
which protrudes a pyramidal elevation of the
second, glassy coat ; the last is lined by a
delicate internal coat containing protoplasm,
starch, oil-globules, &c. Soon after the
expulsion of the spore, cell-formation takes
place inside the pyramidal protrusion of the
outer coat, from the cell-contents of the
spore. The glassy coat next splits at this
point into four teeth, and exposes the cellular
structure (prothallium), which increases in
size, and acquires a green colour. An
archegonium is next formed on this, con-

Fig. 575.

Fig. 578.

Fig. 57a

Fig. 577.

Pilularia globulifera.

Fig. 574. Natural size.

Fig. 575. An ovule spore. Magnified 25 diameters.

Figs. 576 & 577. The same in germination. Magnified 25 diameters.

Fig. 578. Germinating spore more advanced. Magnified 10 diameters.

si sting of a cell (embryo-sac) lying in the
substance at the apex, with a canal bordered
by four papillose cells leading to it. A
spermatozoid fertilizes the free embryo-cell
contained in the archegonium ; and this be-
comes developed into a new plant within
the substance of the prothallmm (fig. 577),
sending out a leaf on one side and an ad-
ventitious root on the other, tangentially to

the surface of the spore. In this stage
(fig. 578) the young plant, with the remains
of the spore, somewhat resembles a germi-
nating Monocotyledonous seed. Finally, as
the young plant increases in size, the rem-
nants of the spore-coat are thrown off.

BIBL. Valentine, Linn. Tr. xvii. ; Hof-
meister, Vergl. Unters. 1851, 103 ; Henfrey,
Ann. N. H. 2. ix. 447; Hanstein, Pilul. #c.

PINE-APPLE.

[ 600 ] PITTED STRUCTURES.

1866, Braun, Monatsb. Berl Ak. 1870;
Sachs, Sot. 444.

PINE-APPLE. See BBOMELIACE^E.

PINNULARIA, Ehr.— A genus of Dia-
tomaceae, family Naviculaceae.

Char. Frustules single, free, longer than
broad ; front view linear or oblong ; valves
navicular, elliptical, lanceolate, or oblong
(side view), with a median line, and a
nodule at the centre and at each end ; sur-
face exhibiting transverse or slightly radi-
ating striae or furrows (costse).

This genus differs from Navicida in the
striae not being resolvable into dots. They
are mostly distinct under ordinary illumina-
tion. In some of the species they are absent
in the middle, leaving a transverse clear
space or band, resembling in appearance the
stauros of Stauroneis. Many species.

P. nobilis (PL 15. fig. 1, side view).
Valves linear, dilated in the middle and at
the rounded ends ; striae , coarse. Fresh-
water and fossil; length 1-100 to 1-70".

P. viridis (PI. 16. fig. 2, side view).
Valves elliptical, somewhat turgid, ends
obtuse ; freshwater ; length 1-600 to
1-220"; common.

/3. Strise parallel, absent from a transverse
band.

P. oblmga (PL 15. fig. 3, side view).
Valves linear -oblong, ends rounded ; fresh-
water and fossil ; length 1-120" ; common.

P. radiosa (PL 15. fig. 4, side view ; fig. 5,
front view). Valves lanceolate, ends some-
what obtuse ; freshwater ; length 1-500" ;
common.

BIBL. Smith, Br. Diat. i. 54, ii. 95 ; Ehr.
Abh. 1840, 20; Donkin, Mic. Jn. 1861, 8;
Pritchard, Inf. 899; Kiitz. Sp. Alg. 81;
Gregory, Diat. of Clyde, 7 ; Q. Micr. Jn.
ii. 28, 98 ; Griin, Wien. Verh. 1860, 524 ;
Rabenh. Alg. iii. 209 ; Pfitzer and O'Meara,
Qu. Mic. Jn. 1872, 386.

PI'NUS, L.— A genus of Conifer* (Gym-
nospermous Flowering Plants), presenting
many interesting points of structure. The
most familiar example is the Scotch Fir
(P. sylvestris) ; but a great number of other
species are cultivated in this country. For
the microscope they yield instructive objects:
— in the wood (PI. 48. fig. 1), composed of
peculiarly pitted cells (see CONIFEBJE) and
traversed by turpentine-reservoirs; in the
BARK, which has a land of false cork ; in
the development of the Gymnospermous
OVULES, and in the structure of the POL-
LEN-grains.

The wood of species of the genus Pinus

frequently occurs in a fossil condition (PL
26. figs. 29-33).

BIBL. See the articles above cited.

PISOM YX' A, CoTd&(Bryocladium, Ktz.).
— A genus of Mucorini (Phycomycetous

Fig. 579.

Pisomyra racodioideu.
Magnified 200 diameters.

Fungi), growing upon leaves. A species
has occurred in Ceylon on the leaves of
Amomum.

BIBL. Fries, Sum. Veg. 406 ; Corda, Ic.
Fung. i. pi. 6. fig. 292 ; Berk, and Broome,
Linn. Jn. xiv. 139, t. x. f. 54.

PISTIL.— The parts of a flower included
in the terms ovary, stjTle, and stigma. It
is in theory composed of modified leaves
or carpels.

PISTILLA'RIA, Fr.— A genus of Cla-
variei (Hymenomycetous Fungi), consisting
of small club-shaped heads which are con-
fluent with the stem. There are about six
species indigenous to this country, of which
that on fern-stems is the most common.

BIBL. Fr. Ep. 586; Berk. Outl. 286;
Cooke, Handb. 342.

PISTILLID'lUM=ARCHEGONiuM, the
female reproductive organ of the higher
Cryptogamia.

PITH. See MEDULLA.

PITHOPH'ORA, Wittr.— An obscure
genus of Algae. (Wittrock, Qu. M. Jn.
1877, xvii. 293; Moore, Jn. Bot. 1877;
M. M. Jn. xviii. 40.)

PITTED STRUCTURES OF PLANTS.
— The secondary deposits of cellulose which
form the layers of thickening of the walls of
vegetable cells are seldom uniform or homo-
geneous in character. In most, if not in all,
cases some special microscopic structure
may be distinguished, either by mere in-
spection or on the application of reagents.
These layers, spoken of more particularly as
to their nature under SECONDARY DEPO-
SITS, may be divided into two classes, com-

PITTED STRUCTURES. [ 601 ] PITTED STRUCTURES.

prehending pretty accurately all the varied
conditions, namely: — the Spiral deposits,
where the secondary layers assume the
aspect of fibres applied upon the inside of
the cell- wall; and Pitted, or, as they are often
termed, Porous deposits, where layers are
applied over the whole internal surface of
the cell, which layers present orifices of dif-
ferent characters, leaving the primary mem-
brane bare, and forming in this way a pit as
viewed from the inside of the cell. When
the secondary layers are comparatively thin,
their presence is often overlooked ; and the
pits have thus often been mistaken for ori-
fices or pores (figs. 580, 581) in the primary

Fig. 580.

Fig. 581.

Pitted cells of Elder pith.
Magnified 250 diameters.

membrane ; but such pores are never origi-
nally present ; the closure of the pit by the
layer of primary membrane may always be
demonstrated in young structures; and when
orifices really do occur in cell-walls, these
arise from the absorption of the primary
cell-membrane converting the pit into a
pore. The best way of demonstrating that
young spotted cell- walls are only pitted and
not perforated, is to apply sulphuric acid
and iodine for the production of the blue
colour in the primary cell-wall.

Simple pits, of no great depth, occur on
the slightly thickened walls of most perma-
nent parenchymatous cells; they may be
seen in the cells of herbaceous stems, in
pith, bark, in the cells of the parenchyma of
leaves, &c. (Figs. 580, 581 j PI. 47. fig. 14.)

In most prosenchymatous wood-cells, or
liber-cells, and in the woody cells of the
stones or shells of fruits and seeds, the pits
are far more clearly evident, and become
more and more distinct (PI. 48. fig. 3), as
the layers of thickening increase in number,
since, by the successive application of these,
the pits are deepened (with the contraction
of the cavity of the cell) until they become
canals^ or tubular passages radiating from
the central cavity (PI. 47. fig. 23). In these
cases it is evidently seen that the pits of
adjacent cells and ducts correspond to each

other at their outer extremity ; and in old
tissues, when the primary cell-walls have
been absorbed, these coincident pits form
tubular canals leading from one cell to
another. It has been observed that two or
more pits sometimes become confluent in
the later internal deposits, so that the in-
ternally simple orifice leads out to several
branches corresponding to the original pits
on the wall of the cell. In rare cases, simple
pits occur on the outer walls of epidermal
cells, as in Cycas (PI. 47. fig. 28).

Pits of the above kinds occur on the
structures called ducts (see TISSUES, VEGE-

Fig. 582. Fig. 583.

Fig. 582. Pitted ducta of Clematis. Magn. 100 diams.

Fig. 583. Side wall of a cell of Pine, with bordv i ed

pits. Magnified 200 diameters.

TABLE), formed of cells applied end to
end and confluent (fig. 181, page 271).
These large pitted tubes (which occur abun-
dantly in most woods, with the exception
of that of the Coniferae) are sometimes
termed bothrenchyma, signifying pitted tis-
sue ; but the character not being exclusively
applicable to them, the name is bad.

In many pitted ducts, and in the pitted
wood-cells of many plants, especially of the
Coniferse, the pits present a greater degree
of complication. The markings on the walls
of the wood-cells of most of the Coniferae,
for example, consist of pits surrounded by a

PITTED STRUCTURES. [ 602 ] PITTED STRUCTURES.

broad rim (fig. 583 ; PL 48. figs. 1, 4, 5); the
portion within the rim projeats somewhat
into the cavity of the cell, and appears like
a lenticular body attached on the wall; hence
the markings were formerly termed the
" glands " of Coniferous wood. In reality,
however, while the pits themselves resemble
ordinary pits, the broad rim, or rather the
circular line outside the pit, depends on a
condition of the cell- wall outside the mem-
brane, and is merely the outline of a lenti-

Fig. 584.

~r.m

Section of Pine wood at right angles to the pitted
walls, p.f, walls of a pitted cell ; c. /, cavity of a cell ;
c. /, lenticular cavity between two adjacent pits ; r. m,
cells of a medullary ray, the pits have no riin here.

Magnified 400 diameters.

cular cavity existing between two adjacent
cells, the boundary of which is visible
through the wall on account of the trans-
parency of the latter : the nature of this
structure is very evident in sections made at
right angles to those which show the bor-
dered pits in face (fig. 584 ; PI. 48. fig. 1 b).
In most of the Coniferae the wood is ex-
clusively composed of large elongated pros-
enchyinatous cells, with bordered pits of
this character on the side walls (that is, on
the walls standing radially or perpendicular
to the bark) ; the pits, however, which lie
on parts of the wall adjoining the cells of

medullary rays, are generally devoid of the
rim.

Similar bordered pits occur very generally
on the walls of the pitted ducts of Dico-
tyledons ; but as the wood is here of mixed
composition, and the ducts adjoin cells as
well as other ducts, independently of the
medullary rays, we often find a greater va-
riety of conditions on the wall of the same
duct, which may have bordered pits when
adjoining another duct, and simple pits, or
pits with a double outline, when adjoining
cells. The pits with a double outline (PI. 48.
figs. 15 6, & 20) are of different nature from
the bordered pits (PL 48. figs. 13, 14, 15 a,
16, 18), the double outline depending; simply
on the fact that the later or more internal
layers of thickening do not reach the edge
of the orifice in the earlier secondary de-
posits, so that the pit is conical, or rather
has sloping edges, the circumference at the
primary membrane being rather less than
that of the margin next the cell-cavity. A
peculiar modification of this unequal mode
of deposit is seen in company with the true
rim or border in many cases (PL 48. figs. 14,
16, 18), where the central spot or original
pit appears in the middle of a slit running
across the circle indicating the border ; this
slit indicates the alteration of the shape of
the gap in the secondary deposits in the
successive layers, and corresponds to the
inner margin of the pit, where this has the
form of an elongated groove or slit, gradu-
ally diminishing to a small round hole
towards the primary cell-membrane (PL 48.
fig. 18 a). Sometimes (PL 48. fig. 18 «, 6)
the two or more slits formed in this way on
contiguous pits become confluent. The last
condition indicates a transition to the more
sparing form of the secondary deposit where
it appears as a modification of a spiral fibre
or fibres; and the later secondary deposits of
pitted ducts do sometimes actually assume
this form, and produce a spiral- librous layer
of thickening inside the layers perforated by
pits. This is the case in TAXUS (PL 48.
tigs. 4), in the Lime (PL 48. fig. 13). and
Mezereon (PL 48. fig. 19 b\ &c.

Hartig and Mohl have described a pecu-
liar kind of pitted tissue formed of cells,
which the former calls Siebrohren, or sieve-
tubes, the latter dathrate cells. They are
thin-walled cells occurring associated with
the prosenchymatous liber^cells of Dicotyle-
dons, and forming part of the vasa propria
of Monocotyledons; having their walls
mi.rked with large shallow pits, the mem-

PITTED STRUCTURES. [ 603 ]

PLAGIOCHILA.

brane of the pits being again very finely
punctate or reticulated ; Ilartig regards the
fine punctuations as holes.

For the guidance of microscopic observers,
we may furnish a series of examples (in ad-
dition to those of the CONIFER^E, PL 48.
figs. 1, 4, 5), of the different kinds of mark-
ing on pitted cells and ducts.

A. Forms where there is no spiral-fibrous
secondary deposit.

a. Bordered pits uniformly distributed,
without reference to adjacent structures ;
Elcpaunm acuminata, Clematis Vitalba (PI.
48. rig. 18).

b. Bordered pits fewer on the walls ad-
joining cells: Acacia lophantha, Sophora
Japonica.

c. Bordered pits on the walls adjoining
ducts, while the walls adjoining wood-cells
have few or no bordered pits, and those
next the medullary rays have pits without
a border : elder, beechj hazel, poplar, alder,
plane, apple, &c.

d. Bordered pits on the walls adjoining
ducts, but with large pits devoid of a bor-
der where adjoining cells : Cassijtha ghibella
(PL 48. fig. 14), Bombaxpentandrum\¥\A&.
tig. 15).

e. A modification of the last, where the
bordered pits have the form of slits as wide
as the ducts when adjoining ducts, while
the walls adjoining cells have large pits
without a border : Chilianthus arboretts
(PI. 48. fig. 17) ; the vine (in a less striking
manner). Erynyium maritimum (PI. 48.
fig. 21) exhibits a condition approaching this.

/. Sieve-tubes or clathrate cells, large thin-
walled cells with round, oval, or elongated
thinner places (pits) on their Avails, the mem-
brane of the pit being finely reticulated or
perforated like a sieve. These are found in
the liber of Dicotyledons, as in Biynonia,
the lime, the vine, elder, pear, &c., and in
the central part of the vascular bundles of
Monocotyledons, as Musa, Asparagus, &c.

B. Forms where a spiral-fibrotis structure is
added after the pits.

g. All the ducts with bordered pits, but
the larger ducts with smooth walls, the
smaller with a spiral fibre : Clematis Vitalba,
Ulmus campestriSj Morus alba.

h. All the ducts closely pitted, with
slender fibres between the rows of pits :
Hakea oleifolia.

i. The larger ducts with pits, the smaller

without ; both kinds with spiral fibres on
the internal surface: Dap/me Mezereum
(PI. 48. fig. 19), Passer ina Jlliformis, Genista
canariensis.

j. The walls adjacent to other ducts
pitted, those next cells with veiy distant
pits, or devoid of them ; all the walls with
fibres : the lime, horse-chestnut, sycamore,
cornel, holly, hawthorn, Prunus Padus, P.
virginiana, &c.

The last set of forms allies these struc-
tures to those characterized peculiarly by
the SpiRAL-fibrous STRUCTURES : and, as
will be indicated there and under S BCOND AR Y
DEPOSITS, the smooth layers of thickening,
such as those between the pits of Ptnus,
may be made to show a spiral structure by
the action of reagents.

For the micro-chemical conditions of
these objects, their development and rela-
tions, see SECONDARY DEPOSITS ; TISSUES,
Vegetable ; and CELL, Vegetable.

BIBL. Works on Structural Botany, and
the Bill, of SPIRAL STRUCTURES.

PLACENTA OF PLANTS.— The region
of the carpel whence ovules arise. Stronu
would be a preferable term.

PLACO'DIUM.— A genus of Placodei
(Lichenaceous Lichens) j 13 species, on
rocks and walls. (Leighton, Lich. Fl. ICO )

PLACOPSIL'INA , D'Orbigny.— Lituolee
of irregular growth and attached, belong to
this subgenus.

BIBL. Carpenter, For. 143.

PLA'CUS, Cohn.— A genus of Holo-
trichous Infusoria. Free, ovate ; surface
indurated, reticular, mouth inferior ; move-
ment rotatory ; length 1-780" : salt water.
(Kent, Inf. 489.)

PLAGIACAN'THA, Claparede.— A ge-
nus of Acanthometrina (Rhizopoda).

Char. The spicula, which are branched
and without a central canal, do not unite
in the centre of the body, but on one of the
sides, so as to form a scaffolding on which
the sarcode rests,- pseudopodia elongating
either at the ends or sides of the spicula to
which they are attached, and which they
unite more or less together.

BIBL. Clap, et Lach. Etudes, 461.

PLAGIOCHI'LA, Nees and Montagne.
— A genus of Jungermannieae (Hepaticae),
containing a number of British species, viz.P.
(Jungermannia,RQok.}asplenioides,spinidosa,
decipiens, resupinata, undulata (tig. 321),
planifolia, nemorosa, and umbrosa, some of
which, especially P. aspknioides (fig. 585),
are among the most frequent and finest

PLAGIODISCUS.

[ 604 ]

PLANARIOLA.

plants of the family, its stems growing from
•°> to 5" long.

BIBL. Hook. Br. Ft. ii. Fl£- 585-
pt. 1, 111; Br. Jung.
pis. 13, 14 ; Ekart, Sijn-
ops. Jung. 6 et seq. pi. 1 ;
Endlicher, Gen. Plant.
Supp. 1, No. 473.

PLAGIODIS'CUS,Gr.
— A genus of Diatoma-
ceae. Allied to Surirella,
but the costae radiating
at the ends. 2 species ;
valves reniform ; Hondu-
ras. (Grunow, M. M. Jn.
xviii. 172, figs.)

PLAGIOG'NATHA,
Duj.— A genus of Rota-
toria containing species
included by Ehrenberg
in the genera Notommata, Diylena, and
Distemma,', distinguished by the arched
back and peculiar jaws.

BIBL. Duj. Inf. 651; Pritchard, Inf.
692.

PLAGIOGRAM'MA. Grev.— A genus
of Diatomaceaj, family Fragilariae.

Char. Frustules quadrangular, united into
a short fascia; valves with two or more
strong, pervious transverse costae, and mo-
niliform generally interrupted strise.

BIBL. Greville, Mic. Tr. 1865, 1866;
Rabenh. Fl.Eur..Alg. i. 117; Pritchard,
Infm. 773.

PLAGIOPH'RYS, Clap.-A genus of
Actinophryina (Rhizopoda).

Char. No carapace, pseudopodia nume-
rous, arising from one point of the surface
of the body. 2 species; freshwater. P. cy-
Imdrica (PI. 52. tig. 17).

BIBL. Clap, et Lach. In/us. 453 ; Archer,
Qu. Mic. Jn. 1871, 146.

PLAGIOPO'GON, St.— A genus of Ho-
lotrichous Infusoria. Free, oval, longitudi-
nally furrowed, oral setae rigid. P. coleps ;
length 1-300' '. (Kent, Inf. 508.)

PL AGIOP'YLA, Stein.— A genus of Ho-
lotrichous Infusoria. Ovate ; mouth ven-
tral, with an undulating membrane ; sur-
face with trichocysts. 3 species j fresh and
salt water. (Kent, Inf. 538.)

PLAGIOT'OMA, Duj.— A genus of Bur-
sarina (Infusoria ciliata).

Parasitic ; in the intestines and their walls
of Vertebrata and Invertebrata, and in the
mucus of Mollusca. 7 species. P. lumbrici,
in the earthworm ; P. coli, in the human in-
testine.

BIBL. Duj. Inf. 504; Clap, et Lach.
Infm. 235.

PLAGIOT'RICHA, Kt.— A genus of
Hypotrichous Infusoria : allied to Oxytriclta.
2 species ; freshwater. ' ( Kent, Inf. '771.)

PLAGIOT'ROPIS, O'Meara.— A genus
of Diatomacese closely allied to Amphi-
prora, Ehr.

BIBL. O'Meara, Qu. Mic. Jn. 1874, 88.

PLANA'RIA, Mull.— A genus of Annu-
loida, of the order Turbellaria, and sub-
order Planarida.

Char. Body soft, flattened, oblong or
oval, not jointed, covered with vibratile
cilia ; neither suckers, bristles, nor leg-like
appendages present.

Some parts of the structure of these ani-
mals have been noticed under ANNULATA
in speaking of the Turbellaria. The mouth
is situated on the under surface of the
middle of the body, at the end of a retrac-
tile proboscis ; there is no anus ; the mouth
leads to a capacious stomach , giving off
dendritically-branched caeca, somewhat as
in one joint of a Tcmia (PI. 21. fig. 14).
Their motion is continuous and gliding,
upon water-plants, or the sides of glass jars.
The anterior part of the body exhibits a
curved row or a single pair of eyes, and
sometimes ear-like projections. They mul-
tiply by division, and the formation of ova,
which are enclosed in a coloured capsule.

Some of the species are very common in
pools, and resemble, at first sight, minute
leeches. P. niyra, which is black, has a
row of marginal anterior eyes, and two
lateral and one mesial projection; length
about 1-2". P. bi-unnea, dusky-brown, with
a dark mesial line ; eyes as above ; length
rather less. P. lactea, cream-coloured,
tinged with pale reddish brown, truncate in
front, -with two slight lateral auricles ; eyes
two or four ; length 1-2 to 3-4". P. torva,
grey or black ; obtuse in front, angles
rounded, centre projecting; eyes two, with
a white halo ; length 1-2". Of the other
species some are marine.

BIBL. Johnston, Non-parasitical Worms ;
Duges, Ann. Sc. Nat. 2. xv. and xxi. j
CErsted, System, d. Plattiviirmer ; Diesing,
Helminth. ; Daly ell, Powers of Creation, ii. ;
Schultze, Naturg. Turbett. ; Huxley, Comp.
An. ; Vaillant, Mn. Mic. Jn. i. 311 ; R.
Lankester, Pop. Sc. Rev. 1867, vi. 388;
Moseley, Phil. Trans. 1877, xvii. 105.

PLANARI'OLA, Duj.— A doubtful ge-
nus of Infusoria.

P. rubra (PI. 31. fig. 65). Aquatic, in

PLANORBULINA.

[ 605 ]

PLATYZOMA.

decomposing vegetable matter ; length I
1-250".

BIBL. Vuj.Inf. 568.

PLANORBULI'NA, D'Orb.— A genus
of Hyaline Foraminifera. Shell spiral,
coarsely porous, subnautiloid or outspread, j
often parasitic; haying from 15 to 200
chambers, with single septa and slight i
rudiments of the canal-system. Aperture j
sometimes produced and lipped. Compla- j
nate (PI. mediterranensis, PI. 24. fig. 10) ;
plano-convex, Truncatidina (T. lobatula, ,
PI. 24. fig. 9) ; rotaliif orm (PI. Haidingerii, \
PI. 24. fig. 6 ; PL veneta, fig. 12) ; or sub- j
uautiloid (Anomalina and Planulina).
Smooth ; limbate (Planulina) ; or granulate. !
In all seas ; fossil in the Carboniferous, ;
Lias, and later formations.

BIBL. Carpenter, For. 206 ; Parker and I
Jones, Phil. Tr. civ. 379.

PLANTA'GO.— The common plaintain ; i
its leaf and hairs furnish excellent exam-
ples of Cyclosis. See Carpenter, Microscope, j
p. 431.

PLANULA'RIA, Defrance.— A notice-
able group of delicate, elongate, flattened
Cristettarice, connecting the nautiloid with |
the marginuline varieties, come under this
name. Recent and fossil.

BIBL. Parker and Jones, Ann. N. H. 3.
v. 114 (crepidula) ; xii. 215 ; 4. viii. 166.

PLANULI'NA, D'Orb.— A subgenus of
Planorbulina j flat, discoidal, subsymmetri-
cal, and with raised margins and septal
lines (limbate). Recent and fossil.
BIBL. Carpenter, Introd. For. 207.
PLASMO'DIUM.— A sponge-like net-
work, formed by the union of the pseudo-
podia of amoeboid bodies.

PLAS'TIDS.— The simplest living forms,
and the most elementary parts of tissues, j
consist of (1) small particles and masses of i
protoplasm without a nucleus or any trace !
of structure (our protoplasts, 1856), (2) of |
similar portions of protoplasm in which a
nucleus has been differentiated. The first
group Hackel terms Cytodes, the second
cells ; and both are grouped under the head
of Plastids.

The cytodes, or the protoplasmic masses
without a nucleus, are : —

Gymnocytodce, or naked cytodes. Such \
are the freely moving Monera, the non- |
nucleated plasmodia of Myxomycetts, and j
of several other Protista, the amoeboid
germs of the Gregarince proceeding from
the pseudo-naviculee, &c.

Lepccytoda, or covered cytodes. These

are plasma-masses without a nucleus, en-
closed in an entire or incomplete membrane
or shell. For example, the encapsuled
resting condition of many jLepo?nonera,mimy
Siphoncea, and numerous other lower plants,
and the so-called non-nucleated cells of
many, higher plants and animal tissues.

The cells or cyta are plasma-masses with
a nucleus, and are divided into : —

Gymnocyta, naked cells. Such are the
naked plasma-masses with a nucleus, but
without a membrane or shell ; for example,
the true Apiosba, the naked zoospores of
Algae, the eggs of Siphonophora, and other
animals, the colourless blood-cells, many
nerve-cells, &c.

Lepocyta, or covered cells. Such are the
cells of animals, plants, and tissues with
nuclei and cell-walls. See PROTISTA,
CYTODE.

BIBL. Hackel, Biol. Studiett, H. i. ; Qu.
Mic. Jn. 1869, 331 ; Hallier, Plastids, 1878.

PLAT'INUM.— The sodio-ehloride of
platinum crystallizes in prisms and plates
which polarize light; while the potassio-
chloride of platinum yields several forms,
which do not polarize light. This reaction
of the soda-salt has been proposed as a
means of distinguishing soda from potash,
or detecting minute quantities of the
former.

BIBL. Andrews, Chem. Gaz. 1852, x. 378.

PLATYCE'RIUM, Desv.— A genus of
Acrosticheae (Polypodiaceous Ferns). 5
species ; tropical. (Hooker, Syn. 425.)

PLATYCHE'LIPUS, Br.— A genus of
Copepodous Entoinostraca. P. littoralis]
brackish water. (Brady, Copep., Ray Soc.
ii. 102.)

PLAT YC 'OLA, Kt.— Like Vaginicola,
but the sheath decumbent, and attached by
one side. Freshwater; several species.
(Kent, Inf. 731.)

PLATYG'RAPHA, Nyl.— A genus of
Graphidei (Lichenaceous Lichens). P. ri-
mata, on ash trees, rare. (Leightoii. Lich.
Flor. 388.)

PLATYS'MA, Hoffm. — A genus of
Ramalodei (^Lichenaceous Lichens). 10 spe-
cies, on rocky mountains &c. (Leighton,
Lich. Fl. 93.)

PLATYTHE'CA, St.— A genus of Fla-
gellate Infusoria. Ovate, with a decumbent
rugose carapace ; flagellum single : length
1-1200" ; on Lemna. (Kent, Inf. 262.)

PLATYZO'MA, Br.— A genus of Glei-
cheuiaceous Ferns. P. microphyllum. Aus-
tralia. (Hook. Syn. 11.)

PLECANIUM.

[ 606 ]

PLEUROSIGMA.

PLEC A 'NI UM, Reuss.— Tertularia with
sandy sh'^ll-tissue come under this heading.

BIIJL. Reuss, SitzHnqub. Wicn, xliv. 383.

PLEOPELTIS, Humb. and Bonpl.— An
exotic genus of Polypodieae (Polypodioid
Ferns), remarkable for the presence of
peculiarly formed so-called paraphyses in
the sori, performing- the function of an
indusium. These bodies are peltate, or
like minute flat mushrooms or umbrellas
expanded over and sheltering the sporanges
(tigs. 586, 587).

Fig. 586.

Fig. 587.

Pleopeltis nuda.

Fig. 586. A sorus, seen from above.

Fig. 587. Vertical section of ditto.

Magnified 25 diameters.

PLEUROCAR'PI.— MOSSES with late-
ral fruits.

PLEUROCAR'PUS, Braun.— A genus
of Zygnemaceae (Confervoid Aluee).

2 species, in* freshwater pools. (Rabenh.
Alt/, iii. 258.)

PLEUROCLA'DIA, Braun.— A genus
of Fucoideoe, group Phaeosporeae. P. la-
cvstris\ freshwater. (Rabenh. Alg. iii. 393.)

PLEUROCOC'CUS, Meneg.— A genus
of Palmellaceae ( Unicellular Algae).

Char. Cells single or collected in glo-
bular or cubical masses, globular or angular
from pressure, with a central nucleus;
cytioderm thick and hyaline ; cell-contents
homogeneous, green or reddish. Multipli-
cation by alternate fission in opposite direc-
tions. "Gonidia formed in special cells.
They present the greatest similarity to the
gonidia of Lichens. Several species =
forms of Protococcus ?

BIBL. Meneg. Nostoch. 38 ; Na'geli, Syst.
124; Rabenh. Alg. iii. 24.

PLEURODES'MIUM, Kiitz.— An ob-
scure genus of Diatoiiiacese, allied to Stria-
teUa ; marine ; Africa.

BIBL. Kiitz. Sp. Alg. 115.

PLEUROM'ONAS', Perty.— A genus of
Flagellate Infusoria.

Char. Reniform, extremely delicate,
small, colourless; flagellum single, from
the concave side of the body, three times
its length. P. jaculans; motion jerking;
stagnant water. (Perty, Lebenxf. 171.)

PLEURONE'MA, Duj.— A genus of
Holotrichous Infusoria, family Colpodina.

Char. Body oblong-oval, depressed, with
a broad lateral orifice, from which a bundle
of long, curved, floating and contiactile
ciliary filaments issue.
^ P. "chrysalis, (crassa) D. (PL 31. fig. 66).
Freshwater. Other species.

BIBL. Duj. Jnfifs. 473; Clap, et Lach.
Inf. 274 : Kent, Inf. 54i>.

PLEUROPH'RVS, Clap.— A genus of
Actinophryina (Rhizopoda).

Char. Body invested with a sheath in-
crusted with extraneous siliceous particles.

P. sphcerica. Freshwater.

BIBL. Clap.etLachm. 7w/?/5.454; Archer,
Qu. Mic. Jn. 1870.

PLEUROPYXTS, Corda.— A genus of
Mucorini (Phycomycetotis Fungi), growing

Fig. 588.

Pleuropyxia microsperma.
Magnified 200 diameters.

upon lejires and stems. This genus is im-
perfectly known.

BIBL. Corda, Icon. Fung. pi. 6. fig. 291.

PLEUROSIG'MA, Smith.— A genus of
Diatomaceae.

Char. Frustules single, free, longer than
broad ; front view linear or linear-lanceolate;
valves navicular, sigmoid, with a longitu-

PLEUBOSIGMA.

[ 607 ]

PLEUROSIGMA.

dinal line, and a nodule in the centre and
at each end.

The median line and nodules consist of an
internal thickening of the valves at the cor-
responding parts ; the line is best seen in
the front view (PI. 15. fig. 16) ; it is occa-
sionally found in a fractured valve, pro-
jecting as a solid highly refractive rod, the
thinner adjacent portions of the valve being
broken away ; for brevity, it may be called
the keel.

The valves exhibit spurious strise, arising
from the existence of rows of dots, of which
we have already treated under DIATOMA-
CEJE. These strise and dots are in most
species very difficult to detect, requiring
the use of "oblique light, and the modern
condensers with the stops ; the principles
which should guide in the search for them
have been explained under ANGULAR APER-
TURE ; the preliminary preparation of the
valves is also essential (DIATOMACE^;, p.
250).

Most of the species are found in salt or
brackish water ; a few in fresh water. They
often abound upon the surface of mud.
Conjugation or the formation of sporangia
has not been observed. The frustules are
sometimes found enveloped in amorphous
mucus, and those of one species have been
found within gelatinous tubes.

Many species have been described, of
which those that have been used as TEST-
OBJECTS will be enumerated. The mea-
surements are mostly those of W. Smith
and R. Beck, with which our own have
coincided very nearly. The species are
arrarged according to the fineness of the
markings, which coincides with the diffi-
culty with which they are detected and
resolved into dots ; and the appended figures
express the number of strife or rows of dots
in 1-1000".

Stria oblique (dots alternate or quin-
cuncial, PL 15. fig. 40).

P. formoswn (PI. 15. fig. 25). Broadly
linear, attenuated towards the ends; sig-
moidure evident ; keel oblique ; length
1-60" ; strise 36. Marine.

P. decorum (PI. 15. fig. 26). Rhomboid-
linear ; attenuated ; sigmoidure very evi-
dent; keel oblique; length 1-90"; strise 36.
Marine.

P. speciosum (fig. 28). Linear-lanceolate ;
sigmoidure resulting from the curvature of
one maigin of each half of the valve, the
opposite margin of each respective half

being nearly straight; keel in each half
forming two curves ; very oblique near the
ends ; length 1-90" ; marine : striae 44. The
halves of the valves somewhat resemble the
blade of a pocket-knife.

P. strigosum (fig. 29). Linear-lanceolate ;
ends rather obtuse, sigmoidure slight ; keel
nearly straight in the middle, curved near
the ends; length 1-90"; striae 45. Marine.
Fig. 40 represents the strise resolved into
dots.

P. quadratum (fig. 34). Rhomboidal, acu-
minate at the ends; sigmoidure evident
towards the ends ; keel curved, nearly me-
dian ; length 1-150" ; marine ; striae 45.

P. elongatum (PI. 15. fig. 31, and PI. 1.
fig. 18). Linear-lanceolate, acuminate ; sig-
moidure slight, uniform ; keel median ; length
1-80" ; marine ; strise 48.

P. riyidum (fig. 30). Linear-lanceolate,
obtuse at the ends ; sigmoidure slight ; keel
nearly median; length 1-70"; marine;
strise 48.

P. angulatum (PI. 15. fig. 33). Rhomboid-
lanceolate or angular-lanceolate ; sigmoidure
evident; keel nearly median; length 1-110";
marine; striae 52. PI. 1. fig. 16 represents
a valve with the striae resolved into dots ;
PI. 15. fig. 41 represents the dots very
highly magnified ; and PI. 15. fig. 46 exhi-
bits the appearance of hemispherules, which
some authors consider to form the tnie
structure.

PI. 15. fig. 33 a represents a specimen
with the endochrome and nucleus.

/3 (fig. 336). Simply and narrowly lan-
ceolate, ends acute.

7 (fig. 33 c). Ends beaked; abruptly
flexed.

P. cestuarii (fig. 35). Lanceolate ; ends
abruptly tapering, short and beak-like ; sig-
moidure evident ; keel not median ; length
1-250" ; marine ; striae 54.

P. intermedium (fig. 36). Narrowly
linear-lanceolate, acute ; sigmoidure none,
! or merely indicated by a slight inequality
in the opposite margins of the valves : keel
nearly straight and almost median ; length
1-140"; marine; striae 55.

ft P. nubecula. Ends obtuse; slightly
more lanceolate, and shorter ; marine ;
striae 55.

P. delicatulum (fig. 32). Very narrowly
linear-lanceolate ; sigmoidure evident ; keel
nearly central; marine; length 1-130":
stria/ 64.

P. obscm-um (fig. 27). Linear, attenu-
ated near the ends ; sigmoidure slight ;

PLEUROSIGMA.

[ 608 ]

PLEUROXUS.

principally arising from the curvature of
one margin of each half of the valve ; keel
not median, especially near the ends ; ma-
rine ; length 1-200" j striae 75.

Stria longitudinal and transverse (dots
opposite, PI. 15. figs. 39, 42).

In most of the following species or forms
the dots are not equidistant in the longitu-
dinal and transverse rows.

P. striyilis (tig. 12). Linear -lanceolate ;
siginoidu're evident ; keel nearly median,
flexure double; marine; length 1-75";
striae : longitudinal 40, transverse 36.

P. balticum (fig. 10). Broadly linear,
narrowed at the ends ; sigmoidure apparent
at the ends only and produced principally
by the curvature of one margin only ; keel
not median, flexure double ; marine ; length
1-80" ; striae, both sets, 38. Fig. 39, piece
of valve, showing dots.

]3. Gradually tapering towards the ends ;
striae obscure.

P. Hippocampus (fig. 13). Narrowly
lanceolate, gradually attenuated towards
the broad, very obtuse ends ; sigtnoidure
evident ; keel 'nearly median ; marine or
brackish water ; length 1-100" ; striae : lo.ig.
32, tr. 40.

P. attenuatum (fig. 15. PI. 1. fig. 17).
Linear-lanceolate, with obtuse ends; sig-
moidure slight ; keel nearly median ; marine
and freshwater ; length 1-1 20" ; striae :
long. 30, tr. 40.

P. lacustre (fig. 18). Linear-lanceolate,
ends rather obtuse j sigmoidure evident ;
keel almost median; freshwater; length
1-130" ; strise, both sets, 48.

P. tenuissimum (fig. 24). Narrowly linear,
attenuate towards the ends; sigmoidure
evident; keel nearly central; freshwater;
length 1-180" ; strife, both sets, 48.

P. Spencerii (fig. 17). Linear-lanceolate ;
sigmoidure evident ; keel nearly median ;
freshwater ; length 1-200" ; striae : long. 55,
tr. 50.

P. littorak (fig. 19). Lanceolate, ends
somewhat prolonged ; sigmoidure evident ;
keel median; freshwater; length 1-180";
striae : long. 24, tr. 50. Fig. 42 represents
the dots upon part of a valve.

P. acuminatum (fig. 14). Linear-lan-
ceolate, acuminate ; sigmoidure evident ;
keel median; freshwater; length 1-150'';
striae : lotfg. 40, tr. 52.

P.fasoiola (fig. 21). Linear-lanceolate ;
with linear baak-like ends ; sigmoidure evi-

j dent j marine ; length 1-200" ; striae': long.
! (?),tr.64.

P. prolongation (fig. 23). Very narrowly
linear-lanceolate, acuminate, with linear
beak-like ends ; sigmoidure present in the
ends only ; keel nearly median ; marine ;
length 1-200 ; striae : long. (?), tr. Go.

P. distortion (fig. 20). Lanceolate; ends
slightly produced and beak-like ; sig-
moidure evident ; keel central ; marine ;
length 1-300''; striae: long. 65, tr. 75.

P. macrum (fig. 22). Very narrowly
linear-lanceolate ; ends produced into long
beak -like processes; sigmoidure produced
by the ends of the beaks only ; keel median ;
length 1-100"; marine; striae: long. (?),
tr. 85.

BIBL. Hassall, Freshwater Alga, 435;
Smith, Brit. Diatom, i. 01 ; Kiitzing, Sp.
Alg. and Bacttl. ; Rabenhorst, Alg. i. 230
(46 European species); and the BIBL. of

DlATOMACEJB.

PLEUROST AU'RUM,Rab. = Stauroneis
united into filaments.

BIBL. Rabenh. Alg. i. 258; O'Meara,
Qu. Mic. Jn. 1872, 387.

PLEUROT^E'NIUM, Nageli.— A genus
of Desniidiaceae, consisting of species of
Closterium, Docidium, and Penium.

BIBL. Rabenh. Fl. Eur. Alg. iii. 140.

PLEUROT'RICHA, Stein. — A genus
of Hypotrichous Infusoria. Like Stylo-
nychia, but without caudal setae, with
larger ventral set*e, and the anal styles in
two groups. 3 species ; freshwater. (Kent.
Inf. 782.)

PLEUROT'ROCHA, Ehr.— A genus of
Rotatoria, of the family Hydatinaea.

Char. Eyes none ; a single tooth in each
jaw; foot forked ( = Hydatina with uni-
dentate jaws).

P. gibba (PI. 44. fig. 18). Body ovate-
oblong, truncate in front ; toes small, turgid.
Freshwater ; length 1-216".

BIBL. Ehr. Infm. 418 ; Gosse, Ann. N.
H. 1851, viii. 199.

PLEUROX'US, Baird. — A genus of
Entpmostraca, of the order Cladocera, and
family Lynceidae.

Char. Anterior part of shell prominent
above, obliquely truncate below ; first pair
of legs very large ; beak sharp, curved
downwards. * Freshwater.

P. triganellus (PI. 19. fig. 32). Beak
long, sharp-pointed, slightly curved down-
wards ; inferior antennae short and slender,
anterior branch with four setae, one from
the first joint, one from the second, and two

PLOCAMIUM.

[ 609 ]

PODISOMA.

from the last ; posterior branch with three
setas, all arising from the last joint.

P. uncinatus. Beak curved upwards at
the end ; 3 sharp spines at anterior inferior
ansrle of shell ; inferior antennae as the last.
P. hamatus. Beak blunt and strong,
slightly curved downwards; first pair of
legs with a curved claw at the end. ? Male
of P. trigonellus.

BIBL. Baird, Brit. Entomostr. p. 134.
PLOCA'MIUM, Lamouroux. — A genus
of Delesseriaceae (Florideous Algae), con-
taining one species, P. coccineum (PI. 4.
fig. 10), the commonest of our red sea-
weeds, with a delicate flat feathery thallus,
from 2 to 12" high, growing in bushy tufts
on rocks or other Algse. The fruit consists
of : — 1. coccidia, spherical, stalked or sessile
tubercles, at the .sides or in the axils of the
ramules, filled with angular spores ; 2. an-
theridia, which occur in inconspicuous flat
patches, composed of short erect cells, upon
the surface of distinct plants ; and 3. sti-
chidia, lateral or axillary, simple or branched
pods containing a single or double row of
linear (transversely parted) tetraspores.

BIBL. Harvey, Mar. Alg. 19; Phyc.
Brit. pi. 44; Grev. Alg. Brit. pi. 12; Thuret,
Ann. Sc. Nat. 4 ser. iii. 19.

PLCEO'TIA, Duj. — A genus of Infusoria,
family Thecamonadina.

Char. Body diaphanous, with several
longitudinal ribs or keels in the middle, and
a rounded perfectly limpid margin. Two
anterior locomotive filaments, one flagelli-
form, the other trailing and capable of
arresting the movement of the body.

P. vitrea (PI. 31. fig. 67). Marine; length
1-1200". Movement slow.
BIBL. Duj. Infus. 345.
PLCESCO'NIA, Vul., = Euplotes, Ehr.
PLUMATEL'LA, Lamk.— A genus of
freshwater Polyzoa, order Hippocrepia,
family Plumatellidae.

Char. Zoary confervoid, branched, tubu-
lar, branches distinct ; tentacular disk cre-
scentic ; ova elliptical, with a marginal ring,
but no spines.

P. repens. Zoary irregularly branched ;
cells subclavate, without a longitudinal fur-
row or keel ; tentacles about 60 ; tentacular
membrane dentate ; ova broad.
a. Adherent throughout.
(3. Attached only at the base.
P. fruticosa. Irregularly branched, at-
tached at the origin only ; cells cylindrical,
and destitute of furrow, but obscurely
keeled ; ova elongated.

P. corattoides. Attached at the base only ;
tubes dichotomous, densely tufted, desti-
tute of furrow and keel; tentacles about
60 ; ova broad.

BIBL. Allman, Freshiv. Polyz. 92 ; Ann.
N. H. 1844, xiii. 330 ; Johnston, Br. Zooph.
402; Parfitt, Ann. N. H. 1866, xviii. 171.

PLUMULA'RIA, Lanik.— A genus of
Hydroid Zoophytes, family Plumulaiiidae.

Char. Polypidom plant-like, rooted, sim-
ple, or branched, feathery ; cells small, uni-
lateral, usually seated in the axilla of a
horny spine; egg-vesicles scattered. Ten
British species.

P. cristata. Stem simple, a single tube,
pinnate; pinnae alternate; cells close, rim
toothed ; vesicles gibbous, girt with crested
ribs.

P. falcata. Stem a single tube, waved,
branched, branches alternately pinnate ;
cells close, shortly tubular, rim entire ; egg-
vesicles oval-oblong; common.

In P. myriophyttum & P. frutescens, the
stem consists of several parallel tubes.

P. pinnata. Linn. Stem a simple tube,
plumose; pinnae alternate, three on each
internode ; cells rather distant, campanulate,
appressed, rim entire ; vesicles pear-shaped,
rini toothed.

P. setacea, Ellis. Stem a single tube,
pinnate ; pinnae alternate, one at each joint ;
joints ringed ; cells very remote, campanu-
late, rim even ; vesicles elliptical, smooth ;
common.

BIBL. Johnston, Br. Zooph. 89 ; Hincks,
Hyd. Zooph. i. 294.

'PLUMULARI'nm— A family of Hy-
droida.

BIBL. Hincks, Hyd. Zooph. i. 279.

PODAXINE'L— A family of Gastero-
mycetous Fungi, none of which are found
in Britain ; they are distinguished from all
allied tribes by a solid column in the centre
of the sporange.

Many of the species grow on the hills of
the White Ant.

BIBL. Montagne, Ann. Sc. Nat. 2. xx.
69; Tulasne, Ann. Sc. Nat. 3. iv. 169;
Currey, Linn. Tr. xxvi. 288.

PODISO'MA, Link.— A genus of Uredi-
nei (Hypodermous Fungi), growing upon
the living leaves and branches of species of
Juniper; the filamentous mycelium creeping
beneath the epidermis, and sending up a
fleshy, stalk-like, tremelloid body (fig. 589),
composed of agglutinated filaments (fig. 590)
terminating in bilocular spores (or two
spores adherent together), each of the cells

PODOCORYNE.

[ 610 ]

PODOSPHEXIA.

having two or four pores, through which
the internal membrane is protruded in ger-
mination.

Fig. 589.

Fig. 590.

Podisoma Juniperi.

Fig. 589. Branch of Juniper with clavate fructification
protruded from beneath the bark. Nat. size-

Fig. 590. Vertical section through a fruit, showing
the filaments terminating in bilocular spores. Magnified
50 diameters.

Four species are described as British : P.
Juniperi-communis, P. Jun.-sabina, P.folii-
colum (on the leaves of J. communis), and
P. fuscum on Pinus halepensis and oxy-
cedrus.

It has been supposed, but perhaps with-
out sufficient grounds, that the Podisoma
of Savine is a condition of Rccstelia cancel-
lata.

PODOCOR'YNE, Sars. — A genus of
Hydroid Zoophytes. 2 species ; on stones
and shells, deep water.

BIBL. Sars, Faun. Lift. Norv. i, 4, t. i. ;
Allman, Ann. N. H. 1859, 1864 ; Hincks,
Hyd. Zooph. 27 ; Agassiz, Sea-side Studies,

1871.

PODOCORYN'ID^E.— A family of Hy-
droid Zoophytes.

Char. Polypes sessile, with a single
whorl of filiform tentacles around the base
of a conical proboscis ; mouth simple. Gen. :
Podocoryne and Corynopsis.

BIBL. Hincks, Hyd. Zooph. 27.

PODOC Y' ATHUS, Kt— LSkePodophrya,
but with two kinds of tentacles, prehensile
and suctorial. P. diadema, marine, length
1-600". (Kent, Inf. 827.)

PODOC YS 'TIS, Ktz.— A genus of Dia-
tomacese, Cohort Surirelleae.

Char. Frustules sessile, cuneate; valves
convex, obovate, with a median line, trans-
verse continuous, and intermediate granular
strise.

P. americana, Bailey (PI. 51. fig. 7)
The only species ; marine = P. adriatica
JLtz.=Doryphora elegans, Roper.

BIBL. Bailey, Smith. Contr. 1854 j Ktz

Bac. 62 ; Roper, Mic. Jn. ii. 284 j Rabenht.
Alg. i. 60.

PODOC YS'TIS,L6v. = Melampsora. See
UKEDINEI.

PODODIS'CUS, Kg.— A genus of Dia-
tom acese.

Char. Frustules single or concatenate,
with a marginal stalk ; valves circular, con-
vex. Marine. No markings visible under
ordinary illumination.

P. jamaicensis (PI. 17. fig. 16). Stalk
elongate, weak. Diameter 1-840".
BIBL. Kiitz. Bacill. 51 ; Sp. Alg. 26.
PODOPH'RYA, Ehr.— A genus of Aci-
netina.

Char. Suckers simple, capitate, in bun-
dles or on the surface, neither on a trunk
nor ramified ; body without a shell, pedun-
culated. Several species, freshwater and
marine; P.fixa (PI. 30. fig. 5, a & b).

BIBL. Ehr. Inf. 305; Clap, et Lach. Inf.
381; Kent, Inf. 813; Gegenbaur, Morph.
Jahrb. 1875.

PODOSI'RA, Ehr.— A genus of Diato-
maceae.

Char. Frustules concatenate, with a la-
teral stalk; valves circular, punctate, con-
vex. Marine. Stalk attached to the centre
of the valves.

P. hormoides (PI. 19. fig. 34). Frustules
2 to 6, depressed-spheroidal, connected by
isthmi or stalks ; hoops obscurely punctate.
Diameter 1-650".

P. Montagnei (Melosira globifera, Ralfs).
Frustules usually 2 ; hoops striate. Diaiii.
1-600".

P. maculata, Smith, Diat.
P. compressa, West, Pritch. Inf. 815.
P. Items, Gregory, Mic. Jn. vii. 85.
BIBL. Kiitz. Sp. Alg. 26; Smith, Br.
Diat. ii. 53 ; Rabenh. Alg. i. 37.

PODOSPHE'NIA, Ehr.— A genus of
Diatomaceae.

Char. Frustules attached, sessile, wedge-
shaped in front view ; ends indented so as
to produce a black line (vitta) in the front
view ; valves convex, obovate, with a lon-
gitudinal median line and transverse striae,
but no nodules. Marine.

The strise consist of rows of dots, some-
times distinct by ordinary illumination, at
others not so.

P. Ehreribergii (PL 17. fig. 17). Frus-
tules truncate at the end in front view;
valves somewhat acute at the ends ; length
1-240".

P. Lyngbyei. Fr. truncate in front view ;
valves rounded at the end ; length 1-350".

PODOSPORIUM.

[ 611 ] POLARIZATION OF LIGHT.

Three other British species.

BIBL. Smith, Br. Dial. i. 82; Kiitz.
Batill. 119; Rabenhorst, Alg. i. 110.

PODOSPO'RIUM, Lev.,= Mdampsora.
See UBEDIXEI.

PODOSTOMA, Clap, et Lach.— A genus
of Amcebsea (RHIZOPODA).

Char. Bodies amoeboid, with 2 kinds of
pseudopodia, one the ordinary, the others
terminating in a flagellum.

P.JUigerum, among aquatic plants.

BIBL. Clap, et Lach. Inf. 441 : Kent.
Inf. 224.

PODU'RA, L. — A genus of Insects, order
Thysanura, family Podurellse.

The original genus has been greatly sub-
divided. In its extended signification, the
characters consist in the thorax being di-
stinct from the abdomen, and in the presence
of a forked tail, bent under the abdomen
when not in use, and enabling the animals
to move by springing or jumping, whence
the common name of spring- tails applied to
them.

They are of a leaden appearance, and
found in shady damp places, as under flower-
pots or stones, in cellars, &c., and are about
1-20 to 1-10" in length. They may be
caught by placing a little flour upon a
piece of paper in their haunts.

Fig. 591.

Pod ura.
Magnified about 15 diameters.

The body is covered with scales (PI. 1.
fig. 12), which are used as test-objects.
Those of the so-called P. plumbea, which is
now described as a Lepidocyrtus, are usually
recommended ; but the most common Po-
dura is not this species. This, however, is
a matter of little importance, because the
scales of several species, belonging to even
different genera, are similar both in form
and markings.

See SCALES OF INSECTS and TEST-
OBJECTS.

BIBL. Gervais, Walckenaer's Aptires, iii.
and the Bibl ; M'lntire, Mn. Mic. Jn. i.

203 ; 1870, 1 ; Beck, Mic. Tr. 1862, 84 ;
Lubbock, Thysanura, Ray Soc.

PODURHIP'PUS, Megn.— A genus of
Thysanura, fam. Podurellse. P. pityriasicus ;
body fusiform, black, legs paler ; producing
pruricro in horses. (Megnin, Paras. 104.)

PLEUROCHILID'IUM,Stein.— A genus
of Holotrichous Infusoria. Free, no cara-
pace, subreniforni, mouth with a narrow
undulating membrane. P. strigilatum,
among Lemnce. (Kent, Inf. 540.)

POLARTSCOPE.— A term employed to
designate a polarizing apparatus, consisting
of a polarizer and analyzer. See INTRO-
DUCTION, p. xx.

POLARIZATION OF LIGHT. — The
phenomena exhibited by microscopic ob-
jects, when viewed by polarized light, are
perhaps the most beautiful and interesting
of those connected with the use of the
microscope. The extreme brilliancy, trans-
parency, and variety of the colours deve-
loped cannot be equalled ; much less can
they be represented by illustrations, although
the figures in PL 39 may give some idea of
the manner in which they are arranged in
certain objects.

The ordinary arrangement of the parts of
the polarizing apparatus scarcely needs de-
scription,— the polarizer being placed be-
neath the object and the analyzer above it,
the polarizer and analyzer usually consisting
of two Nicol's prisms, although two plates
of tourmaline are sometimes used. Some
artificially prepared crystals exert a power-
ful polarizing action, and may be used either
as polarizers or analyzers, or as both ; among
these the salt of QUININE called Herapa-
thite occupies the first place. Others form
interesting analyzers, some of which have
been noticed under ANALYTIC CRYSTALS
and DICHROISII.

Numerous salts and other crystalline
bodies, which powerfully depolarize the
already polarized light, and exhibit beauti-
ful colours, are mentioned under their re-
spective heads ; some of these may be enu-
merated here — as the oxalate of ammonia,
of soda, and of chromium and ammonia,
the oxalurate of ammonia, the acetate of
copper, chlorate of potash, the prismatic
form of the ammonio-phosphate of mag-
nesia, the ammonio-phosphate of soda, the
sulphates of cadmium and of magnesia,
selenite, salicine, fused santonine, uric acid,
&c.

Many animal bodies and tissues also
possess considerable depolarizing power, and
2n 2

POLARIZATION OF LIGHT. [ C12 ] POLARIZATION OF LIGHT.

form beautiful microscopic objects — as
horse-hair, portions of feathers, sections of
quill, of hoof. horn, fish-scales (salmon),
&c.

The influence of vegetable structures on
polarized light has been thoroughly investi-
gated by Mohl, whose interesting account
we are able to confirm, and a brief notice of
it is desirable here; but the observations
apply equally to the more feebly anisotro-
pous tissues of animals. As it is desirable
to obtain as much light as possible, a glass
prism is preferable to the ordinary mirror
for illumination ; Nicol's prisms are better
than tourmaline or Herapathite for the pola-
rizer and analyzer ; and the latter should
be as large as possible. Further, the light
emerging from the polarizer should, if
possible, be condensed by an achromatic of
large aperture ; or the condensation may be
effected by a hemispherical flint-glass lens,
5 lines in diameter, havdng its plane face
turned towards the object. The object-
glasses must be of large angular aperture ;
a power of 4-10" is sufficient for most
objects; but 1-4", and even 1-8" object-
glasses may be made to transmit sufficient
fight. It is requisite to provide plates of
the doubly-refracting substances mica and
gypsum, mounted so that they can be in-
serted between the polarizer and the con-
denser, and revolved horizontally while so
placed. Those of mica are used for de-
tecting weak degrees of doubly-refracting
power, being of such thickness as to give a
grey field with a white or black object
when the prisms cross. The thin laminae,
of which six may be provided, from the
thinnest possible up to 1-20'", should be
cemented with Canada balsam between
glass plates. For obtaining colours, plates
of gypsum, similarly mounted, are best.
Mohl prefers such as give a red field, and
provides plates of different thickness, giving
the reds of the different orders of Newton's
rings.

It is easy to ascertain whether an organic
body shows positive or negative colours,
by comparing its colour, when seen with a
plate of gypsum in a certain definite posi-
tion, with' the colour given under the same
circumstances by a strip of glass brought
into a state of tension by slight bending, or
with the colours of a suddenly-cooled glo-
bule of glass. In this way the author de-
termined that the fibres of a spiral vessel
displayed negative colours, and the laminae
of a starch-corpuscle positive colours, and

then applied these organic structures, by
comparison, for ascertaining the properties
of other objects. The objects to be exa-
mined should be mounted in a liquid or
other substance rendering them as trans-
parent as possible, such as glycerine, Canada
balsam, or an essential oil.

When ordinary globular or cylindrical
cellular tissues are viewed by cross sections,
their substance is seen to be doubly refrac-
tive ; for when the prisms cross, the circular
sections of the cell-walls appear like rings
of bright light on a black ground, but with
the ring divided into four quadrants by dark
stripes, as if a black cross lay over it; when
the prisms are placed parallel, the parts of
the section previously bright appear dark,
and vice versa, on a bright field. If a sec-
tion of polyhedral cellular tissue is viewed
in the same way, the appearances are
somewhat different, since the cut edges
are here straight lines, variously inclined
towards the prisms ; those which are per-
pendicular to the prisms are invisible,
while those standing obliquely are bright
in their whole length. In general, cell-
membrane acts more powerfully on the
light the denser its substance, and soft col-
lenchymatous tissues are far less powerfully
doubly-refractive than wood-cells. When
the cells have the walls much thickened, it
is common for the primary cell-membrane
to be much more powerfully refractive than
the secondary layers. The' influence of cel-
lulose membranes upon polarized light is
not much affected by bleaching them with
nitric acid and chlorate of potash (Schultze's
reagent). It has been supposed that the
remarkable effect produced by the epidermis
of Equisetum hyemak is attributable to the
silex present; but Mohl finds the action
greatly weakened by destroying the organic
matter by a red heat. But this heating
does not remove the power there, nor in
the Diatomaceae, of which Mohl confirms
Bailey's statement, in contradiction to Eh-
renberg, that various species of Navicula,
Synedra, Pletirosigma, and Melosira are de-
cidedly doubly refractive.

Very remarkable phenomena are pro-
duced when the polarized light is made to
pass through plates of mica or selenite. In
the first place, thin plates of mica often
allow of the discovery of a doubly-refracting
power too feeble to be detected by the
prisms alone — the degree of illumination of
the object being slightly different from that
of the field on which it is viewed. But the

POLARIZATION OF LIGHT. [ 013 ]

POLLEN.

most important matter is the revelation, by
the use of the selenite plates, of the exist-
ence of positive and negative characters,
like those of positive and negative crystals,
in the chemically distinct constituents of
vegetable tissues.

Let us suppose that between the lower
prism and the object is placed a plate of
seleaite giving a red field ; the plate is then
rotated so that its neutral axes are at an
angle of 45° with the prisms. A section
of a cylindrical vegetable cell will be seen
to be divided into four quadrants : the two
alternate quadrants, whose middle lines cor-
respond to the neutral axes of the selenite,
are either blue or green, the other two
yellow or red : if the selenite is then rotated
so that its neutral axes are perpendicular to
the prisms, the colours will be all lost ; but
on continuing the rotation, they reappear in
the reverse order — what was blue appearing
yellow, and vice versa. When the walls are
rectilinear, all the cell-walls perpendicular
to one of the prisms will give the colour of
the field, all those which run parallel with
one of the neutral axes of the selenite plate,
or form no great angle with it, will be blue,
those parallel with the other axis yellow.

It is found that vegetable structures fall
into two classes in reference to these colours,
in one of which classes all layers lying ob-
liquely in the direction of a right- wound
screw are tinged blue and yellow, those
oblique in the opposite direction yellow or
red ; in the other class, the colours under
the same conditions are just the reverse ; so
that one class are optically positive, the
other optically negative.

The optically negative are the ordinary
cell-membranes of the internal organs of
plants, whether in their natural condition
or cellulose purified by the help of nitric
acid and chlorate of potash : collenchyma,
horny endosperm-cells, the gelatinous cells
of Algae, &c., all agree in this property.
Optically positive colours are given by cell-
membranes of periderm and the cuticular
layers of epidermal cells. The contrast of
the positive and negative colours of the
cuticle and other parts of the cell-wall is
well seen in the epidermis of Aloe. The
diversity of colouring under polarized light
here corresponds to the diverse behaviour
under treatment with iodine after macera-
tion in solution of potash (SECONDARY
DEPOSITS).

The longitudinal sections of all behave
like the cross sections ; but the appearances

are not so clear. When side views of the
surface of cells are obtained, the phenomena
are very varied ; but these are best seen in
vessels or ducts when the thickening layers
are in the form of spiral bands. Thus, if
one of the spiral .vessels of Musa is placed
(its spiral somewhat drawn apart) with its
long axis perpendicular to one of the prisms,
the fibres on the upper side turn to the left,
those on the under side towards the right ;
and when the selenite plate is interposed,
they exhibit the complementary colours.
When the side walls of cells have obscure
striation, as in the cells of Conifers, the
liber-cells of Apocynese, &c., the membrane
gives evidence of "its fibrillar structure by
the yellow or blue colour developed with
the selenite plate. If fibres of a spiral
vessel cross at right angles, and they are
pressed together, they neutralize one another
where they cross : when the prisms are
used alone, the crossing points are black,
the rest of the fibres white ; when the
selenite plate is interposed, the crossing
points exhibit the colour of the field, and
the uncrossed portions of the fibre are blue
or yellow according to position.

The vicinity of a round bordered pit, as
in the wood-cells of Piniis, exhibits a black
cross when seen perpendicularly by polarized
light. The black cross and the colours ex-
hibited by starch are well known. Chloro-
phyll does not seem to act on polarized
light, nor the primordial utricle of cells,
except a trace when contracted by weak
alcohol.

The polarization apparatus is exceedingly
useful for the detection of crystals (RAPHI-
DES) in vegetable tissues, when they are so
small as to be easily overlooked j and the
larger kinds form beautiful objects with,
and often without the selenite plate.

BIBL. Herschel, Encycl Metrop. art.
Light ; Pereira, Lect. on Pol. Light, by B.
Poivell; Brewster, Optics; Erlach, Beobacht.
iib. organ. Element, bei polar. Licht, Milllers
Archiv, 1847 ; Valentin, Untersuch. 1861 ;
Lobb, Qu. Mic. Jn. viii. 107; Carpenter,
The Microscope ; Beale, How fyc. j JDavies-
Matthews, Mounting fyc.

POLLEN.— This name is applied to the
coloured pulverulent substance familiar to
every one as occurring scattered in the in-
terior of full-blown flowers ; it is produced
in the anthers, the (usually) stalked club-
shaped organs which stand in one or more
circles between the floral envelopes and the
pistils, and is discharged from them when

POLLEN.

[ 614 ]

POLLEN.

ripe, in order to fertilize the ovules. When
slightly magnified, the pollen of most
flowers appears to consist of granules, of
different size and colour in different plants ;
hence the individual particles are called
pollen-grains or granules (PI. 40). Exami-
nation under a sufficient magnifying power
shows that the simple or typical forms of
pollen-grains are single free cells filled
with fluid matter: more complex forms
occur in many cases, which, however, may
be simply characterized as simple pollen-
grains, permanently coherent into definitely-
formed groups.

The pollen-grain may be examined as to
its form and stucture, its contents, and its
development.

The forms of simple grains presented in
different plants are tolerably varied — sphe-
rical (PL 40. figs. 8-10, 22, 23, 25) and
elliptical (figs. 6, 11, 29) being perhaps
those most common ; but besides these, nu-
merous geometrical forms occur, such as
tetrahedral (fig. 14), polygonal (figs. 16, 27,
28), cubic (fig. 19). But it must be noted
here that the forms frequently vaiy accord-
ing as the pollen is viewed dry or in fluid,
since the elliptical and allied forms often
expand into a spherical form, when they
absorb liquid (figs. 18 & 20 «, 6, c). The
explanation of this will be given presently.
The external appearance is further greatly
influenced by minor peculiarities of form,
such as ridges, spines and processes of dif-
ferent kinds ; these, however, are referable
to the structure of the outer coat.

The ordinary structure of the coats or
the cell-wall of the pollen-grain is that of
a delicate internal cell-membrane, with an
outer, thick and resisting layer, which may
be regarded as the CUTICLE of the inner or
proper membrane of the cell. In a few
cases the inner membrane alone exists, as
in the cylindrical pollen-cells of Zostera
and some other aquatic plants. In other
cases the outer or cuticular coat presents a
more complex structure, and two, or, it is
said, even three layers may be distinguished
in it ; these, however, seem to be merely a
lamination of the outer coat. The condi-
tions in some of the Coniferae are different
from this, and will be alluded to presently.
The inner membrane is exceedingly deli-
cate and homogeneous : in ordinary spherical
or oval grains it accurately lines the outer
coat ; in some of those forms which present
processes of various kinds, such as (Enothera,
it seems to us that the inner coat does not

extend into these processes in the mature
pollen. The outer coat exhibits, as to sur-
face, every variety of appearance, from
smooth, through granular and spiny, to
pseudo - cellular arising from reticulated
ridges; in addition to this, the processes
just alluded to give a very peculiar aspect
to many kinds of pollen. Besides these, we
find in all cases markings appearing like
pores, or others like slits (which become
furrows when dry), or both together, and
these in varying number in different cases.
The colour of the pollen presents great dif-
ferences; although usually yellow, it may
be whitish, red (Verbascimi) , blue (Epilo-
bium angustifolium) , even black (tulip) : this
colour resides in the outer coat. The outer
coat also exhibits, in the majority of cases,
a secretion upon its surface, of a viscid cha-
racter, usually described as oily, but appa-
rently consisting of a viscid matter not
readily soluble in water, remaining from
the dissolved parent cells. It would seem
to be the substance which holds together
the pollen-grains in those cases where it
consists of waxy masses, readily breaking
up into small fragments (Ophrydeous Or-
chids). In the Onagraceae the pollen-grains
are loosely connected by slender viscid fila-
ments, which appear to be derived from
the same source.

The more detailed explanation of the
character of the pores &c., the projecting
processes, and the compound conditions of
pollen will be understood better after a
sketch of its development.

The anther, in which the pollen is formed,
consists in its younger stages of a minute,
solid, cellular- papilla or cylindrical body.
At an early period a distinction becomes
manifest in its cells : a single vertical row,
lying in the position of the axis of each
pollen-chamber (or loculus), presents a
different aspect, from its cells exceeding the
surrounding ones in size ; and these rows
undergo a special development to produce
the pollen-grains, while the surrounding
layers are developed into the tissues forming
the coat or wall of the anther, and its mid-
rib or connective (see ANTHER). The cells
of the primary row multiply by cell-division
with the general increase in size of the
anther (figs. 592-594), until at length they
form relatively large masses of cellular
tissue composed of large squarish cells
filled with granular contents, well defined
as constituting a distinct tissue from the
walls of the pollen-chambers. A new

POLLEN.

[ 615 ]

POLLEN.

Fig. 592.

Fig. 593.

Cl

Fig. 594.
CL Ci CM

Vertical sections of a cell of a yonng anther of the
Melon, showing the gradual separation of the regions.
CE, epidermal cells ; CI, cells of the wall of the anther;
Ci, cells lining the loculi; CM, cells from which the
pollen is developed.

Magnified 100 diameters.

change then takes place : the contents of
each cell secrete a layer of cellulose, which
does not adhere to the wall of the parent
cell to form a layer of secondary deposit,
but lies free against it, so that a new free
cell is formed within each old one, nearly
filling it. The walls of the old cell (form-
ing a connected parenchymatous tissue)
then dissolve, so that the new cells be-
come free, no longer merely in their parent
cells, but in a cavity which is to constitute
the pollen-chamber or loculus of the anther.
These free cells are the parent cells of the
pollen of authors. A new phenomenon soon
occurs in these. These parent cells divide
into four by ordinary cell-division, either
by one or by two successive partings by
septa at right angles to each other but both
perpendicular to an imaginary axis (as when
an orange is quartered), or by simulta-
neously-formed septa which cut off por-

tions in such a manner that the new cells
stand in the position of four cannon-balls
piled into a pyramid (tetrahedrally ). These
new cells are the special parent cells of the
pollen j and in each of these the entire pro-
toplasmic contents secrete a series of layers,
which in the ordinary course, by the solu-
tion of the primary walls of the special

Fig. 596.

Fig. 597.

Pollen-grain of the Melon in various stages of de-

velopment.

Magnified 100 diameters.

parent cells upon which they were applied,
become the walls of free cells, which con-
stitute the simple ordinary pollen-cells.
These subsequently increase in size ; and
their outer laminae assume the characteristic
form and appearance while free in the
chamber of the anther (figs. 595-597).

In referring the peculiarities of many
kinds of pollen to circumstances connected
with the development, it may be noted in
the first place, that the mode of division of
the parent cells into quarters often influ-
ences the ultimate form of the pollen-grain :
thus, when the division is by two planes at
right angles, the original form of the pollen-
grain will be elongated, and the ripe grain
will probably be elliptical, while, when the
division is " tetrahedral," the grains may
retain the form thus produced, or be slightly
modified and become polygonal, or, as is
more common, they expand more readily
than the others into a sphere. But there is
no absolute rule here ; we find even the
tetrahedral and the polar division occur
together among the parent cells of the same
anther. In the next place, a compound
condition of the pollen-grains (PI. 40. figs.
7, 17) is readily explicable by referring it to
an arrest of the process of subdivision ; so
that if the walls of the special parent cell
do not dissolve, the pollen-grains will be
left in groups of four ; and if the parent
cells do not become singly detached in the

POLLEN.

[ 616 ]

POLLKX.

antecedent process of solution, the grains
may be still developed in the same order
and manner and remain connected in greater
or smaller ma-ses or groups, each enclosed
in its special parent cell, itself connected
•with a number of others of the same gene-
ration by the persistence of the walls of the
cells in which the parent cells were deve-
loped. This explains the compound pollen
of the Acacias (PI. 40. fig. 25), and, as an
excessive form, the waxy pollen-masses
which occur in the Orchidacese and Ascle-
piadaceae. It is sometimes stated that the
pollen-grains of these compound forms are
merely connected together by the viscid
substance remaining from the solution of
the parent cells ; but this would render such
cohesions indefinite in character, instead of
being regular ; at the same time it will be
understood that the solution may have ad-
vanced so far that the grains merely hold
together slightly, and may readily be sepa-
rated. This is not the case, however, with
the majority of compound pollen-grains.
When pollen-grains do become free, the
viscidity of their surface is probably refer-
able to the dissolved parent cells.

The metamorphoses of the outer coat or
cuticle of the pollen-grain are very remark-
able, and not yet at all understood; the
granulations (PI. 40. figs. 11, 12), spines
(figs. 8, 9, 22, 26), reticulations (figs. 13, 23,
27, 28), &c. characterizing mature grains
make their appearance in the interval be-
tween the solution of the special parent
cells and the bursting of the anther, while
the pollen-grains lie free within the latter ;
their production is accompanied by a gene-
ral growth and expansion of the pollen-
grain. We have observed that the outer
coat is often deposited as a very thick layer
inside the special parent cell, and that, when
the latter dissolves, the outer coat of the
pollen-grain is also in a softened condition,
and becomes stretched by the expanding
inner coat, finally forming a comparatively
thin layer on the ripe grain (e. g. in Tra-
descantia). The mode of origin of the
markings, like those on SPORES and on the
cuticle of Helleborus &c. (see EPIDERMIS),
is altogether unknown ; probably all the
cases are referable to one cause.

It has been mentioned that the mature
pollen-grain exhibits pores or slits. We
believe they should rather be regarded as
thinner places in the outer membrane. Their
number and position varies much, as will
be indicated presently on referring to some

of the principal types of form of pollen.
The slit-like markings are generally ac-
companied by a peculiar shrinking of the
pollen when dry, the coat collapsing at
the thin places, so that grains of this
kind appear oval or angular, not clearly ex-
hibiting the slits (which then become fur-
rows) ; but they swell out and display the
latter clearly when placed in water or di-
lute acids (PI. 40. figs. 18 & 20). ^Vhen
the so-called pores exist, they are either
like simple pores (PI. 32. fig. 10), or they
may be provided with little disk-like pieces
or lids, which fall off and leave them bare
when the pollen-tube is formed (figs. 13 &
22). In all cases, however, we believe that
the outer coat is extended over the whole
surface, and that the slits and dots are
merely thinner places ; moreover, in certain
cases (Leschenaultia, a quaternate pollen)
we have seen the thickening layers of the
young pollen-grain, inside the parent cell,
exhibit pits (exactly comparable to those of
ordinary pitted cells) at the places corre-
sponding to the future pores, and, curiously
enough, in some cases at least, the pits of
adjacent pollen-cells corresponding, although
in the mature expanded compound grains
they were far separated. Sometimes the
lids are found at trie end of short projecting
processes (PI. 40. fig. 22). The pollen of
(Enothera and allied genera exhibits remark-
able conditions, which have been mistakenly
described. The form of the grain is that of
a depressed sphere with three large equi-
distant truncated cones projecting pretty
nearly in the same plane. The outer coat
is thick, except at the ends of the conical
masses ; and two laminae are distinguishable
(PI. 40. fig. 14). The outer coat thins otf
towards the end of each process. It ap-
pears to us that the inner coat or true
pollen-membrane does not extend into the
processes at all, but is globular, and that a
semifluid deposit occupies the space between
the inner coat and the outer, in the cavity
of the tubular processes. Now, supposing
such a deposit to become hardened and,
after circumscissile fission, pushed off as a
plate by the advancing pollen-tube, instead
of giving way and expanding, we should
have the lid occurring in Cucurbita Pepo
(PI. 40. fig. 22) and other cases.

Is has been stated that the pollen is the
agent of fertilization of the ovules in the
Flowering plants. When scattered from
the anthers, that portion of the pollen
which falls upon the stigma (and frequently

POLLEN.

[ 617 ]

POLLEN.

other portions falling upon nectaries or
secreting surfaces) swells slightly, and ger-
minates as it were, sending out a delicate
tubular process from one or more of the so-
called pores or slits (PI. 40. fig. 30), which
processes (the pollen-tubes) insinuate them-
selves between the loosely packed cells of
the stigma, and, continually elongating,
make their way down the style and along
the conducting tissue to the ovules. In the
Coniferae the pollen-grains fall directly upon
the micropyle of the naked OVULE, and
send their pollen-tubes into it. The pollen-
tube is produced by the development of the
inner or proper coat of the pollen into a
tubular filament. When pollen-grains are
placed in dilute sulphuric acid or in syrup
(sometimes in water), they absorb liquid,
swell, and their contents partly exude from
pores &c.j either to a slight extent, as a
little "hernia," as it were, of the inner
membrane, or in large quantity in a worm-
like, irregular mass ; in the latter case the
coagulation of the surface often produces a
pellicular coat. These exuded masses are of
course distinct from the true pollen-tubes
produced under natural conditions.

The fluid contents of the pollen-grains
consist of a granular viscid protoplasm, with
minute starch-granules and (apparently)
oil-drops, making together what has been
called the fovilla, which increases in density
as the pollen ripens. The starch-granules
exhibit molecular motion in the pollen-
tube, and still more clearly when they
escape by rupture. The granular contents of
the pollen-cell, which are always rendered
opaque by the action of water, are gradually
transferred to the pollen-tube as it elongates.

Connected with this point is the pecu-
liarity exhibited by the pollen of the Coni-
ferse. In the Abietinese the form of the gra-
nules is very peculiar — elongated, curved,
and with bulging ends ; and, according to
Schacht, a distinct internal cell exists, at-
tached at one side in the cavity of the ordi-
nary pollen-cell, this internal cell dividing
and growing out as the pollen-tube when
the pollen-grain comes upon the ovule.
The pollen of the Cupressineae is spheroidal ;
but free cellules appear to be formed in the
pollen-tubes during the f ertilizatiou. These
conditions, which are not yet satisfactorily
cleared up, indicate a relation to the sper-
matozoid-producing spores of the Marsilea-
cese, &c., analogous to that between the
Gymnospermous ovules and the ovule-spores
of those Cryptogamic families.

It has been imagined that the form and
structure of the pollen-grains might have
some relation to the general structure of
the plants, and might serve as an indication
of systematic position and affinities. But
there appears to be no definite relation ;
very varied pollen occurs within the limits
of the same family, and very similar pollen-
grains in families widely distant. There
appears, however, to be a certain relation
within the limits of genera. It may be per-
haps generally stated that the Monocotyle-
dons have frequently one pore or furrow ;
the Grasses often three pores, as is the case
with many Dicotyledons, many of which
have more, while a large number of the
families of the latter division exhibit both
pores and slits. As microscopic objects, it
is most convenient to class the forms arti-
ficially, or according to structure ; and we
give a brief list of the principal varieties
arranged under this point of view.

The pollen-grains of Zostera, Zanichellia,
and other submerged aquatic plants, have
no cuticle or outer coat ; all other known
forms possess one or more outer layers.

A. Outer coat without furrows or pores.

a. Outer coat granular : Strelitzia Regince,
Calla palustris, Crocus sativus, fyc.f
Asarum ewop&um, Laurus nobilis, fyc.,
many Euphorbiaceae.

b. Outer coat with papillae : Canna indica.

c. Outer coat with cell-like reticulations :
Ruettia formosa (PI. 40. fig. 23), R.
strepens, Tribulus terrestris.

In Periploca grceca (PI. 40. fig. 15) and
Apocynum venetum (fig. 7) grains of this
kind are connected in fours in one plane ;
in some Luzulee tetrahedrally.

B. Outer coat presenting longitudinal fur-

rows (or folds).

* One furrow (the form of most Mono-
cotyledons).

a. Outer coat finely granular : common
in Monocotyledons • among the Dico-
tyledons, in Myrica ceri/era. Magnolia
grandiflora, Liriodendr'on tulipiferum,
$c.

b. Outer coat granular, spiny : Nympluea
alba.

c. Outer coat with cell-like reticulations :
Hemerocallis fulva, and other Monoco-
tyledons.

POLLEN.

POLLEN.

d. Outer coat with irregular reticulations :

Alstrccmeria Curtisiana.
Among the Orchideae are found quater-
nate grains belonging to this group.

** Outer coat with two furrows : a rare
form, occurring in species of Ponte-
deria and Amaryllis, Tamus commu-
nis and elephantipes, Tigridia pavo-
nia, Calycanthus jftoridus, fyc.

*** Outer coat with three longitudinal
furrows.

a. Outer coat granular. One of the com-
monest forms: Quercus Robur, Viola
odorata (PI. 40. fig. 6).

b. Outer coat with short spines : Cactus
flagellifonnis, Viscum album.

c. Outer coat with cell-like reticulations :
Statice (PI. 40. fig. 29), various Cruci-
ferae.

Outer coat with more than three
furrows.

a. Four : very rare as normal, Houstonia
cceruka, Cedrela odorata] occasionally
occurring where three is the normal
number, as in Solanum tuberosum.

b. Six : some of the Labiatae and Passi-
floreae (PI. 40. fig. 20), Ephedra dista-
chya, Heliotropium grandtflorum.

c. A large number of furrows : many
Rubiaceae, e. g. Sherardia arvensis (PI.
40. fig. 18).

The pollen of the Pines is related to this
group, also that of Nymphcea Lotus, Victo-
ria regia, and other plants, where the fur-
rows or thin places occupy the greater part
of the wall, and the outer coat forms only
segmental pieces. In Thuribergia alata
(PI. 40. fig. 24 a) a remarkable appearance
arises from the furrows running in a curved
or spiral direction.

C. Outer coat with pores.

* A single pore : Grasses, Sedges, Ty-
pha angustifolia, Sparganium ra-
mosum.

** Two pores : Colchicum, and a few
other Monocotyledons; also Brous-
sonetia.

*** Three pores.

a. Outer coat granular : Dipsaceae, Urti-
cacese, Onagraceae [here the pores form
projecting processes (PI. 40. fig. 14) ;

and in Morinda persica this is still more
the case] ; Cucumis sativus.

b. Outer coat with cell-like reticulations :
many Passifloreae — with large lids, P.
cceruka (PI. 40. fig. 13), alata, fyc.
#*** Four pores.

a. Pores on the equator : Pistacia tere-
bintlius, Campanula rotundifolia, fyc.

b. Pores not equatorial : Passiflora ker-
mesina, Impatiens Balsamina (PI. 40.
fig. 21) (Noli-me-tanyere).

***** More than four pores,
t Distributed regularly.

a. On the equator : Alnus glutinosa, Ul-
mus campestris, Collomia linearis, Cam-
panula Speculum.

b. All over the grains : Basella alba (PL
40. fig. 19).

ft Scattered irregularly.

a. Outer coat slightly granular : many
Nyctagineae, Convolvulaceae, Chenopo-
diaceae, Alsineae, Alisma Plantayo (PI.
40. fig. 10), Plantago lanceolata, Riles
nigrum, Cactus Opuntia, fyc.

b. Outer coat granular and spiny : Cucur-
Uta Pepo (with lids, PL 40. fig. £>),
Malvaceae (fig. 26).

c. Outer coat with cell-like reticulations :
Polygonum amphibium, pei'sicaria, Co-
bcea scandens.

Compound porous forms occur in some
of the Onagraceae, and in Drimys Winteri,
where four grains are conjoined tetrahe-
drally. In the Mimoseae groups of eight
or sixteen (PL 40. fig. 25) occur in various
forms. In Leschenaultiaformosa the grains
are quaternate, lying in one plane.

D. Outer coat with both furrows and pores.

* Grains rounded or depressed, with
three depressions, each with a pore :
most Dipsaceae and Geraniaceae
(sometimes only two occur, PL 40.
fig- 22).

** Three furrows and three pores.

a. Outer coat granular : a very common
form among Dicotyledons.

b. Outer coat spiny : most Compositae.

c. Outer coat with cell-like reticulations ;
rare : Syringa vulgaris, Ligustrum vul-
gare, Grewia occidentalis, and other
species.

POLLEN.

[ 619 ]

POLYCYSTINA.

*** Outer coat with more than three
furrows, each with a pore. Some-
times abnormally, instead of three,
but normally in most of the Boragi-
nacese and Polygalaceae.

**** Six to nine furrows, three con-
taining a pore : Lythraceae, Mela-
stoniaceae, Combretaceae.

***** Three or four furrows, with six

or eight papillae : Neurada procum-

bens, fyc.
****** Three furrows and three papillae

not in the furrows : Carolinea cam-

pestris, SfC.

Starch-corpuscles exist in the fovilla of
some pollen-grains in the form of very small
grains which are stained blue by iodine.

Related compound forms occur in the
Ericaceae and Epaciidaceae, where the grains
are tetrahedrally arranged (PI. 40. fig. 17).
Other aberrant forms occur in which the
single grains are cubic or dodecahedral ;
and in the Cichoraceae polyhedral forms of
complicated character are common (figs. 16,
27, 28).

Mature pollen-grains should be observed
dry (as opaque and transparent objects), and
in water or glycerine ; in some cases, in oil ;
treatment with acids is also useful in making
out structure. In observing the develop-
ment of pollen, it is necessary to wet the
object with a solution of sugar or gum;
otherwise the appearances are altogether
changed through endosmotic action.

BIBL. Nageli, Entwick. des Pollens, 1842,
and on Cell-formation, Ray Society, 1846,
1847 ; Hofmeister, Sot. Zeit. vi. 1848 ;
Gieswald, Linncea, xxv. 81 ; Schacht (Coni-
ferae), Beitrag z. Sot. 1854; Saccardo,
Nuovo Giorn. Sot. 1872 ; Hassall, An. N. H.
1841 & 1842 (pis.) ; Smith, M. M. Jn. xvii
9 (figs.); Edgeworth, Pollen, 1877 (446
figs.), & M. M. Jn. xviii. 190; Qu. M. Jn
1880, xx. 19; Warming, HansteirfsBot.Abh
1873.

POLY AC 'TIS.— Separated from Botrytis
on account of the dark, quasi-carbonizec
flocci.

POLYARTHRA, Ehr.— A genus o
Rotatoria, of the family Hydatinaea.

Char. Eye single, cervical ; foot absent
body with six cirrhi or fins on each side.
Jaws each with a single tooth.
P. platyptera (PI. 44. fig. 19). Body
ovato-subquadrate, fins ensiform serrate
freshwater ; length 1-190".

P. trigla. Fins setaceous; freshwater
ength 1-190".

BIBL. Ehrenberg, Infos, p. 440.
POLYCLI'NUM, Sav.— A genus of Tu-
nicate Mollusca, of the family BOTBYLLID.S:
[p. 115).

P. aurantium. Consists of little rounded
orange masses, fixed to rocks by a short
and thick peduncle.

BIBL. Forbes and Hanley, Br. Moll i.
14.

POLYCOC'CUM, Sant.— A genus of
Micro-lichens, parasitic on the prothallus of
Stereocaulon condensation.

Char. Spores eight, small, bilocular,
brown.

BIBL. Lindsav, Qu. Mic. Jn. 1869, 343.
POLYCOC'CUS, Kiitz.— Probably be-
longs to Microcystis (Rab., Alg. ii. 55).

POLYCO'PE, Sars.— A bivalved Ento-
mostracon of the Cladocopa group. Upper
and lower antennae both natatory and seti-
ferous ; two pairs of posterior limbs, the
first natatory, the second branchial; no
eyes ; no heart ; intestine imperforate.
Valves circular, thin, smooth, or orna-
mented. Marine ; recent and fossil.
BIBL. Brady, Linn. Tr. xxvi. 470.
POLYCYS'TINA, Ehr.— A family of
Radiolarian Rhizopoda.

The animal bodies are contained in shells
of various forms (PI. 39. figs. 23-31).
These are rounded, conical, oval, radiate,
star-shaped &c., often furnished with spines
and other processes, and sometimes con-
stricted so as to give them a jointed ap-
pearance. The shells are siliceous, every-
where perforated by coarse, rounded or
angular foramina; and at one end, some-
times at both, is a larger aperture. The
animal matter is olive-brown or yellowish.
The Polycystina have been found on nearly
every ocean-bottom. Ehrenberg found
them at Cuxhaven, and in the Antarctic
seas ; Bailey in the depths of the Atlantic ;
Miiller in the Mediterranean, and Hackel in
the Adriatic ; Wallich in the Indian Ocean;
and Wyville Thomson, Carpenter, and
Gwyn Jeffreys in the deep-sea soundings of
the North Atlantic. The siliceous skeletons
or shells accumulated in thick deposits
during the last geological periods ; and
myriads of these exquisite microscopic forms
may be obtained from many strata in Sicily,
Greece, Oran, Bermuda, Richmond, Vir-
ginia, and Barbadoes. They are rare in the
Chalk.

BIBL. Ehr. Monatsb. Berl Ak. 1846,

POLYCYSTIS.

[ 020 ]

POLYNEMA.

1850; Microg. 1854; Miiller, Thalass. #
Polycyst., Abh. Ak. Wiss. Berlin, 1858;
Haeckel, Radiolarien, 1802 ; Furlong, Qu.
Mic. Jn. i. 1801-64; Claparede et Luch-
mann, Inf. 434; Wallich, Tr. Mic. Sac.
n. s. xiii. 7o ; Thomson, Deep Sea, 98.

POLYCYSTIS, Kutz.-See CLATHRO-
CYSTIS. Is a Microcystis.

POL YC YS'TIS, Le veillS ( Uroci/stis,
Hallier). — A genus of Ustilagiuei (Hypo-
dermous Fungi), including several of the
old species of Uredo ; P. colchici, P. paral-
lela, and P. violce are British. See USTILA-
GINEI.

POLYE'DRIUM, Nag.— A genus of
Unicellular Algae.

Char. Cells single, 3-4-8-angular, the
angles more or less produced. Several
species, in freshwater pools. P. longi-
sjnnum (PI. 3. fig. 13).

BIBL. Rabenh. Aly. iii. 01 ; Archer, Qu.
Mic. Jn. 1871, 90.

POLYEM'BHYONY.— This term is ap-
plied to a phenomenon occurring sometimes
jegularly, sometimes abnormally in the de-
velopment of the ovules of Flowering Plants.
In the Angiosperrnous plants it is usual to
find several germinal masses in the unferti-
lized embryo-sac (see OVULE); but ordinarily
only one of these becomes impregnated and
developed. Occasionally, however, more
than one commences the course of develop-
ment into the embryo, as in the Orchidacese,
and more especially in the genus Citrus: in
most cases all but one become subsequently
obliterated; but in the orange this is not
the case, and ripe seeds are met with con-
taining more than one embryo. We have
met with them in other cases.

Another kind of polyembryony occurs in
the Santalacese. Viscum has two or three
embryo-sacs ; these may all have their ger-
minal masses fertilized, and the develop-
ment of the embryos may go on to a certain
point, until one takes the lead and the
others disappear.

In the Gymnospermia (Coniferae and Cy-
cadaceas), as described in the article OVULE,
there may be one or more (Taxus) primary
embryo-sacs, in which are produced several
corpuscida, with secondary embryo-sacs;
further, the germinal masses of these, after
fertilization, produce suspensors, which
branch at their lower ends, and each pro-
duces four rudimentary embryos, all but
one of them vanishing during the ripening
of the seeds. Our space only admits of a
brief notice of these interesting phenomena,

on which much interesting information will
be found in the works referred to below.

BIBL. Meyen, On Impregnation and Poly-
embryomj, Taylor's Sc. Mem. iii, 1 ; Brown,
Ann. N. H. xiii. 368 ; Mirbel and Spach,
Ann. Sc. Nat. 2. xx. 257 ; Criiger, But. Zcif.
ix. 57 ; Gelesuoff, Ann. Sc. Nat. 3. xiv. 189,
and the works of Hofmeister cited under
OVULE.

POL Y^GAS'TRIC A.— According to Eh-
renberg's system, the Infusoria were sub-
divided into the Polygastrica and the Rola-
toria. The so-called Polygastrica now cor-
respond to the Infusoria; the Rotatoria
forming a distinct class.

POLYI'DES, Ag.— A genus of Crypto-
nenriaceae (Florideous Algre), containing
one British species, P. rotundus (PI. 4.
fig. 3), having a branched frond 4 to 6"
high, consisting of repeatedly dichotomous,
purplish-brown, solid fibres, about l-'JO" in
diameter. The fibres present a central layer
of longitudinally arranged filamentous cells,
and a cortical layer of perpendicular, dicho-
tomous filaments, formed of elliptical cells
internally, terminating at the surfa- -e in
minute moniliform rows. The fructification
consists of: — 1. favellce bearing spores, con-
tained in superficial wart-like bodies, com-
posed of colourless articulate filaments ; 2.
tetrahedrally divided tetraspores, embedded
in the peripheral filaments of the cortical
layer of the frond. Antheridia have not
yet been observed.

BIBL. Harvey, Mar. Alg. 146; Pliyc.
Brit. pi. 95 ; Greville, Al<j. Brit. pi. 11.

POLYKRIKOS, Butschli.— A genus of
Holotrichous Infusoria. P. iSchwurtzii,
marine. (Kent, Inf. 508.)

POLYMORPHPNA, D'Orb.— A genua
of Hyaline Foraminifera. Inequilateral,
oblong or elongate, globose or compressed
(PI. 23. fig. 40, P. communis; fig. 42, P.
oblonga ; fig. 43, P. compressa] ; chambers
often numerous, alternate in two rows,
slightly embracing, but always more so on
one side than the other ; orifice round, at
the summit of the last chambers, radiate.
Sometimes the later chambers have branch-
ing, tubular apertures (P. Orbignii. PI. 23.
fig. 41).

Many species in all seas ; fossil from the
Trias upwards.

BIBL. Williamson, JRec. For. 70; Car-
penter, For. 166 ; Brady, Parker, and Jones,
Linn. Tr. xxvii. 197.

POLYNE'MA.— A genus of Hymenop-
terous insects. The perfect insect is aquatic

POLYCECA.

[ 621 ]

POLYPI.

in its habits, swimming by means of its
wings. It lays its eggs inside those of
Dragonflies.

BIBL. Lubbock, Linn. Tr. 1863 j Metam.
Insect. 37.

POLYCE'CA, Kt— A. genus of Choano-
flagellate Infusoria. Like Salpinyceca, but
the carapaces united into a branched zoary.
P. dichotoma, marine. (Kent, Inf. 360.)

POLYOM'MATIJS, Latr.— A genus of
Lepidopterous Insects, of the family Lycae-
nidae.

Char. Antennae terminated by a con-
tracted knob ; tarsal claws minute ; wings
not tailed.

The (thirteen) species are small butter-
flies, the upper surface of the wings of a
beautiful blue colour, the under side grey
or brownish, and with numerous eye-like
spots.

The scales upon the under surface of the
wings of P. argiolus and P. argus have
been proposed as test-objects. They are of
two kinds — one resembling in structure the
ordinary scales of insects, the other of a
battledore form (PI. 34. figs. 20 & 21). See
SCALES of INSECTS and TEST-OBJECTS.

The species are figured in Westwood's
British Butterflies.

POLY^PHE'MUS, Mull. — A genus of
Cladocerous Entomostraca, family Poly-
phemidae.

Char. Head distinct from the body ; ab-
domen long, slender, and projecting exter-
nally from the shell.

P. pediculus (PI. 19. fig. 29). The only
species. Freshwater.

BIBL. Baird, Brit. Entomostr. Ill ; An.
N. H. 1877, xix. 119 ; Claus, Polyph. 1877.
POLYPHRAG'MA, Reuss. — A. large
stichostegian Arenaceous LitKola, with nu-
merous short chambers and cribrate septa.
Fossil ; Cretaceous. Saxony and Bohemia.
BIBL. Von Reuss, Geinit^s Elbthalgebirge,
I. iv. 139.

POLYPI.— A group of Zoophytes, com-
prising the Actinaria and Hydroida. Body
rounded or cylindrical, with a distinct
rnouth, surrounded by retractile non-ciliated
tentacles or radiating lobes: individuals
usually aggregate; gemmiparous and ovi-
parous.

The polypes are usually enveloped in an
external (PI. 41. figs. 46, 12, & 14), or
supported by an internal axial skeleton
(PL 41. fig. 6), called the polypidom. This
is either horny, leathery, or calcareous.
Most polypes are united into smaller or

larger groups by the polypidom, which
often possesses an elegant plant-like form
(PL 41. fig. 15). The tubular or cup-
shaped processes or cavities in which the
body of the individual polypes is contained,
form the polype-cells or capsules ; they are
sometimes furnished with a kind of lid.

The structure of the calcareous polypi-
dom s has not been satisfactorily deter-
mined. They are usually traversed by vas-
cular canals, and appear in some cases at
least to consist of aggregated and fused
spicula.

The polypes are rarely free, or capable of
fixing themselves by a disk at the base of
the body, as in Hydra, being usually fixed
at the bottom of the polype-cells, the poly-
pidoms being attached by a rooting base to
some foreign body. Imbedded in the outer
parts of the soft substance of the body,
especially the tentacles, are stinging organs
(PL 41. fig. 22), resembling in general those
of the Acalephae.

In many, distinct muscles are present ;
but the fibres are not transversely striated,
although frequently exhibiting wrinkles. In
some polypes, the substance of the body
consists entirely of sarcodic substance. In
many, both the integument and the sub-
stance of the body contain calcareous spi-
cula (PL 41. figs. 7, 27, & 28).

The alimentary apparatus consists of a
mouth and a simple gastric sac, the food
being admitted and the undigested portion
rejected from the single aperture, except in
one genus, where the anus is separate. The
oral orifice is usually surrounded by a ring
of contractile arms and tentacles, which are
hollow internally, and communicate with
the cavity of the abdomen ; sometimes the
tentacles are distributed over the surface of
the body.

The simple gastric cavity is usually sepa-
rated from the cavity of the body j where-
by a larger or smaller abdominal cavity is
formed, which is usually prolonged into
the hollow arms, and in many polypes
living in colonies passes into the canals
traversing the interior of the polypidom, so
that the abdominal cavities of the indi-
vidual polypes are all brought into con-
nection by these canals. Sometimes longi-
tudinal partitions run like a mesentery
from the outer to the inner surface of the
abdominal walls, thus dividing the abdo-
minal cavity into chambers. The bottom
of the gastric cavity is provided with one
or more spontaneously closeable openings,

POLYPI

[ 622 ]

POLYPODIACE^E.

by which it communicates with the abdo-
minal ca.vity. The gastric cavity is covered
with ciliated epithelium, which is continued
through the gastric apertures into the ab-
dominal cavity, and here not only covers
the outer surface of the stomach and the
septa, but also the inner surface of the ab-
dominal walls, the cavities of the arms, and
the canals of the polypidom.

The walls of the ' stomach are variously
coloured, white, yellow, or brown, from the
presence of aggregations of pigment-cells
(liver cells), which probably perform the
function of a liver, as there is no glandular
appendage corresponding to a liver pre-
sent.

A peculiar circulation takes place in most
polypes, by the to-and-fro motion of a
nearly transparent liquid containing minute
colourless corpuscles, in the abdominal
cavity. In the colonial polypes, this circu-
lation continues through the canals which
traverse the polypidoms, from one abdo-
minal cavity to the other.

The propagation of the polypes takes
place : oy spontaneous division, which is
mostly longitudinal and rare ; the forma-
tion of gemmae or buds, which is very com-
mon, the individuals either separating ^ or
remaining attached ; and by the formation
of ova. Most of the gemmae become deve-
loped into ordinary polype-cells, and so
produce the growth of the compound orga-
nism. But in many polypes, some of them
grow into large cells, of different form from
the common polype-cells, constituting the
ovarian vesicles, or capsules (PI. 41. figs.
14 b and 16 b). In these, the gemmae,
which are developed within them, and
which are often called ova, gradually be-
come bell- or disk-shaped, and assume the
form of Acalephce-, and on escaping from
the vesicles, swim about freely, subsequently
either becoming directly developed into
new polypes, or acquiring sexual organs
and producing ova.

In other (simple) polypes, distinct sper-
matic and ovi-sacs occur in the parent
animals; either together in the same ani-
mal, and external (Hydra), or separately in
different individuals and internal (Actinia,

&c.).

The ovum-embryo of the polypes is
usually more or less elongate-oval, coated
with cilia, and moves about on its long
axis like an infusorium. After a short
time, it fixes itself to some object, the cilia
disappear, and the tentacles of the polype

are protruded ; as these polypes increase by
gemmation, new colonies are formed.

The formation of coral reefs and islands
by the skeletons of polypes is well known.

The new names of the Polype-structures
will be found in the Art. HYDROIDA, and
Hincks's ' Zoophytes.'

POLYPODIA'CE^E. — An order of
Ferns, divided into 13 families by the cha-
racters of the sporanges.

Synopsis of the Families.
* Sori with an indusium (except Alsophila).

CYATHEJE. Sporanges numerous, sori on
a raised receptacle, with a somewhat ob-
lique annulus.

DICKSONIE^E. Sori globose, on the back
or apex of a vein ; indusium subglobose,
free, at length bursting irregularly, more
frequently cup-shaped, entire or with 2
lips.

HYMENOPHYLLEJE. Sori terminal or
marginal from the apex of a vein ; recep-
tacle elongate, often filiform, and more or
less exserted, clothed with sessile orbicular
subpeltate compressed capsules, with a
transverse ring opening vertically.

DAVALLIEJE. Sori rounded, marginal or
submarginal, covered by a reniform or
rounded scaly indusium open at the apex,
fastened broadly at the base, and open at
the sides.

LINDSAYE^, Sori in a line at or near
the end of the frond, inner valve of indu-
sium membranous, the outer formed of the
margin of the frond.

PTERIDE^E. Sori marginal, linear or ob-
long ; indusium of the same shape as the
sorus, formed of an altered and reflexed por-
tion of the frond, opening inwardly.

BLECHNE^;. Sori linear or oblong, dor-
sal, parallel with the midrib and edirr of
the segments, not close to the latter ; indu-
sium shaped like the sorus, superior, open-
ing towards the midrib.

ASPLENIE^!. Sori attached to the veins,
oblique or subparallel to the midrib, linear
or oblong. Indusium shaped like the sorus,
when single, opening towards the midrib,
sometimes double.

SCOLOPENDEIE.S;. Sori as in Aspleniese,
but the indusia arranged in pairs and open
towards each other.

AspiDiE^E. Sori dorsal, subglobose,
rarely elliptical ; indusium superior, shaped
like the sorus, fixed either by the centre or
a sinus.

POLYPODIES.

[ 623 ]

POLYSTOMELLA.

** Indusium absent.

POLYPODIES. Sori on the back of the
lobes, round or rarely oblong, not more
than twice as long as broad.

GBAMMITIDES. Sori on the back of the
lobes, more than twice as long as broad,
usually linear.

ACBOSTICHES. Sori spread over the
under surface or rarely both surfaces of the
frond, not confined to the veins.

POLYPODIES.— A family of Polypo-
diaceous Ferns; contains the single genus
Poll/ podium.

POLYPODIUM, Linn.— A genus of
Ferns with naked sori, of which there are
several indigenous representatives, P. vul-
gare, the Oak-Fern, being- one of our com-
monest species. Exceedingly well adapted |
for examination of the structure of the sori
and sporanges in this family.

POLYPOR'EI. — A family of Hymeno-
mvcetous Fungi, characterized by bearing
baddiospores lining tubes, pores, or pits,
on the underside of a stalked or sessile
j> ileus, or fleshy cap or disk. The basidio-
spores are seen by horizontal sections from
the undersurface of the pileus. (See BA-
SIDIOSPORES and HYMEXOMYCETES.)

BIBL. Berk. Fruct. of Fungi, Ann. N. H.
i. 81 ; LeYeille", Ann. Sc. N. 2. viii. 324.

POLYSAC'CUM, D. Cd.— A genus of
Trichogastres (Gasteromycetous Fungi),
having a common peridium filled with
peridiola ; the spores mixed with threads.
One species only occurs, and Tery rarely in
this country. Abroad they grow on exposed
sand. One of the species has been used in
dyeing. -P. crassipes, p. 349, fig. 269.
"BIBL. Fr. Syst. Myc. iii. 54; Berk.
Outl. 304; Sow. t. 425; Cooke, Handb.
375.

POLYSEL'MIS, Duj.— A doubtful genus
of Infusoria, of the family Euglenia.

Char. Oblong or variable in form, with
several anterior flagelliforrn filaments, and a
single red eye-spot.

Probably the zoospore of a Confervoid
Alga.

P. viridis (PI. 31. fig. 68) resembles a
Euylena of an oblong form with the ends
rounded ; one of the filaments is longer than
the three or four others which surround its
base. Freshwater ; length 1-650".
BIBL. Dujardin, Infus. 370.
POL YSIPHO'NIA, Grev.— An extensive
genus of Rhodonieleee (Florideous Algae) or
Red sea-weed.s, with cylindrical, more or less

Fig. 598.

articulated fronds, the joints consisting of a
circle of longitudinally arranged cells sur-
rounding a central cell, like the wood-
bundles of a young Dicotyledonous stem
surrounding the pith, so that the transverse
section presents the appearance of a rosette.
The number of peripheral cells varies among
the 300 different species of this genus, from
four to twenty-five ; the British forms
mostly have four and six. In some of the
species a kind of rind is formed subsequently,
by a growth from the base of the joints
analogous to that which occurs in BATRA-
CHOSPERMUM and CALLITHAMNION. The
fructification consists of: — 1. ceramidia, urn-
shaped or ovate, attached to the sides of
branches, containing nume-
rous pear-shaped spores at
the base ; 2. tetraspores on
distinct plants, formed in the
swollen central cell of dis-
torted branches (fig. 598) ;
these are gonidia and develop
a thallus ; and 3. antheridia,
elongated whitish sacs, col-
lected in great numbers at
the summits of the branches,
accompanied by a dichoto-
rnous .hair, and sometimes
prolonged into a hair-like
process at the summit. Nageli
describes the spermatozoids
as consisting of a spiral fila-
ment. Thuret states that
they are merely hyaline glo-
bules, about 1-5000" in dia-
meter, without active motion.
The British speciesareplaced
in two subgenera — Oligosi-
phonia, where there are but
four or rarely five peripheral
cells, and Po/y*e)?A0ma, where
there are six or more.
Twenty-six species are de-
scribed, many of which are common.
fastigiata, PL 4. fig. 20.)

BIBL. Harvey, Mar. Alg. 82, pi. 12 A ;
Thuret, Ann. Sc. N. 3. xvi. 16, pi. 6 ; Nageli,
Zeitsch. wiss. Sot. 1846, 207, pis. 6 & 7 ;
Henfrey-Masters, Sot. 433.

POLYSTOMEL 'LA, Lamk.— A genus of
Hyaline Foraminifera. Shell free, regular,
equilateral, biconvex, sometimes compressed,
often dorsally keeled; spire embracing;
chambers with a single cavity, straight or
arched, meeting at the umbilicus and fur-
nished with transverse pits between the

Magn. 50 diams.

(-P-

POLYTHALAMIA.

[ 624 ]

POLYTRICIU M.

sutures or over them. Orifices numerous,
arranged along the margin of, or forming a
triangle at, the upper part of the last cham-
ber. Polystomella passes into Nonionina,
through P. striato-punctata (PI. 24. f. 19),
common in cold seas.

P. crispa (PI. 24. fig. 20) is common in
temperate seas. P. craticulata is of tropical
growth. P. macella (Faujasina) is unsym-
metrical and starved. Many fossil forms.

BIBL. D'Orbigny, For. Vim. 121 ; Wil-
liamson, Foram. 39 ; Morris, Br. Fossils, 40 ;
Parker & Jones, Ann. N. If. 3. v. 103 ;
Carpenter, For. 276.

POLYTHALA'MIA. See FORAMINI-

FERA.

POLYT'OMA, Ehr.— A genus of Fla-
gellate Infusoria, family Monadina (Hydro-
morina).

P. uvella (PI. 31. fig. 69, undergoing di-
vision), the only species, is oblong or oval,
obtuse at the ends, colourless, furnished with
two flagelliform filaments ; it has no cara-
pace. Fresh or decomposing water ; length
1-2200 to 1-960"; size of body when the
division is nearly complete, 1-400".

As it increases in size it assumes a wrinkled
or mulberry appearance, and this indicates
the approaching division into many sections,
whence the name.

BIBL. Ehr. Inf. 24 ; Schneider, Ann. N.
H. 1854, xiv. 321 ; Pritchard, Inf. 136 &
504 ; Kent, Inf. 301.

POLYTRE''MA, Blainville.— A protean
parasitic Foraminifer of the Rotaline family ;
scale-like, globular, or arborescent, with
cancellated structure. P. miniaceum is
widely distributed in the Mediterranean and
other warm seas.

BIBL. Carpenter, For. 235; Schultze,
Wiegm. Arch. 1863, 81 ; Ann. N. H. 3. xii.
409 ;' Carter, ibid. 4. xvii. 185 ; 5. v. 440.

POLYTKICHA'OEJS. — A tribe of
Mnioideae (operculate Mosses of usually
Acrocarpous habit).

Genera.

Catharinea. Calyptra narrowly hood-
shaped, subscabrous at the apex, rather hairy
within. Peristome simple, composed of
thirty-two teeth, arising from a narrow,
cellular basilar membrane, ligulate, mem-
branous, white, with many percurrent,
reddish, inarticulate filaments, somewhat
incurved, scarcely hygroscopic, firm. Colu-
mella dilated at the apex into a drum-like
epiphragm. Capsule equal. Inflorescence
monoecious or dioecious.

Fig. 599.

Polytrichum. Calyptra dimidiate, but
appearing campauulate on account of a
quantity of very close hairs descending from
it as a long villous coat ; otherwise resem-
bling the preceding genus.

POLYT'RICHUM, Dill. — A genus of
Polytrichaceous Mosses, variously defined by
different authors. In the British Flora, it in-
cludes the forms separated in this work under
CATHARINEA, which in the ' Bryologia Bri-
tannica ' are divided between Atrichum and
Oligotrichum. The species of Polytrichvin
comprised in our definition are distributed in
the same work under Pogonatum (those with
a round capsule and thirty-two teeth) and
Polytrichum proper (those with a square or
prismatic apophysate capsule (fig. 600 ), and
usually twice as many
teeth). P. commune is
one of our finest Mosses,
common on heaths,
moors, and mountain
tracks, varying some-
what under the differ-
ent physical conditions.
The stems are from
6" to 1' long, and the
fruit-stalks 2 or 3".
The stems are almost
of woody texture, the
leaves large and firm.
The calyptra is densely
covered with hairs.
Wilson remarks that
the true structure of the
sporange and columella
of Mosses may be most
easily learned from
the study of this
genus. The columella
is seen (figs. 601, 603),
to be separated from
the spores by an
inner layer of the spo- Polytrichum commune,
rangial membrane. The
diaphragm attached
to the apices of the
teeth of the peristome is
the dilated apex of the columella (fig. 603).

The peristome (fig. 602) is composed of
ligulate obtuse teeth, connected by a mem-
brane at the base, continuous with the inner
layer of the wall of the capsule. These
plants are also exceedingly well adapted for
the examination of the male inflorescence
and spermatozoids. They are all dioecious ;
and the male plants (fig. 604) are readily
distinguishable by the cup-shaped inflores-

Plants in fruit.
One half natural size.

POLYTRIOHUM.

[ 625 ]

POLYZOA.

cence, composed of scale-like leaves and
paraphyses surrounding a number of subu-
late sacs constituting the antheridia. The
male flowers of P. commune tfuwiperinum, &c.

Fig. 600.

Fig. 601.

Polytrichum commune.

Capsule with operculum. Section of young capsule
Magnified 10 diameters.

showing the plaited spo-
rangial membrane.

are found everywhere on heaths in spring.
The antheridia may be readily extracted un-
der a simple lens, and, when placed in water

Fig. 602.

Fig. 603.

Polytrichum commune.

Fragment of peristome. Columella with section

Magn. 100 diams. of tne apophysis.

Magn. 25 diams.

under the compound microscope, soon (if
ripe) burst at the summit and dis charge the
spermatozoids ; these usually escape still
enclosed in their parent cells, which when
first discharged cohere in a gelatinous mass ;
but the ciliated spermatozoids (PI. 40. fig.
33) escape and swim actively in the water.

They require at least an eighth object-glass
for examination ; and the cilia are seen most
clearly after drying the object, or treating
it with tincture of iodine.

Fig. 604.

Fig. 605.

Polytrichum commune.

Male inflorescence. Innovation from male

One half nat. size. inflorescence.

Magn. 5 diams.

BIBL. Wilson, Bryol Brit. p. 205 et sea. :
Thuret, Ann. Sc. Nat. 3. xvi. 26. pi. 14.

POLYZO'A or BRYOZOA.— A class of
Animals, belonging to the subkingdom
Mollusca.

Char. Polypif orm, aggregate ; individual
bodies microscopic, contained in horny or
calcareous cells, often connected by tubular
stems, forming a usually branched zoary ;
mouth surrounded by long, ciliated, uncon-
tractile tentacles ; mouth and anus separate,
but near each other. Marine and fresh-
water.

They are found everywhere on the sea-
shore, either rooted to, or forming a crust
upon submerged rocks, stones, shells, &c.
The individual is called a polypide ; and
the aggregate or colony constitutes a
ccencecium or polyzoarium ; it is usually
of a whitish or brownish colour, of a
horny or calcareous texture, and consists
either of cells or cups simply aggregated
(PL 41. figs. 17, 20), or connected by tubu-
lar stems, and often arranged in elegant
plant-like forms (PI. 41. fig. 5 a). The
stems are divided into compartments by
perforated septa (PI. 41. fig. 5 /), through
which thread-like filaments of the sarcode

2s

POLYZOA.

020 ]

POLYZOA.

The cells are of various forms, mentioned
under the genera, and they are often furnished
with bristles or spines. At the orifice of
each cell the tentacles and more or less of
the body of the animals are protruded. In
the marine or Infundibulate order, the struc-
ture of the cell-mouth is used as a charac-
ter,— those in which it is terminal and simple
(PI. 41. fig. 30) forming the Cyclostomata ;
and those in which it is subterminal, curved,
and furnished with a movable lid, the
Cheilostomata (PL 41. fig. 56); whilst in
the Ctenostomata there is a comb-like cir-
cular fringe of bristles connected by a mem-
brane surrounding ths cell-orifice, visible
when the body is partly protruded. Most
are fixed j but Cristatella is free and loco-
motive, having a discoid base.

Curious appendages are found attached
mostly to the cells of the polyzoaries. The
first are called bird's-head processes or avi-
cularia (PL 41. fig. 56*, and fig. 26).
They consist of a body (fig. 26 d), a hinge-
or lower -jaw-like process (fig. 26 e), and a
stalk (/). They are attached by the stalk
to the interior of a round hollow process,
projecting slightly from the surface of the
pol'yzoary (fig. 26 a). The body is divided
by an oblique ridge (fig. 26 d) on its inner
surface into two chambers. The lower
portion is moved up and down by an
elevator and depressor muscle (fig. 26 c).
During life the motion is constant; and it
continues long after the death of the animal.
These bodies appear analogous to the pedi-
cellaria of the Echinoderinata.

The second kind, called vibracula, consist
of a hollow process (fig. 5 d, 6), from which
a vibrating filament (fig. 5 d) projects.
The interior of the process is filled with a
contractile substance which moves the
filament.

The body is usually oblong or elongate.
At its anterior end is a ring or disk (lopho-
phore), upon which the tentacles are placed ;
this is perfect in the Infundibulata, but
deficient at one part, or horse-shoe shaped
in the Hippocrepia (PL 41. figs. 3 c & 9).
The tentacles are hollow, closed at the end,
uncontractile, coated externally with cilia
on the sides next each other, and communi-
cate with the cavity of the body through
apertures in the disk. In most of the Hip-
pocrepia, the tentacles are surrounded at the
base by a transparent cup -like membrane
(ca&^r), prolonged somewhat upon each ten-
tacle, and mostly dentate at the margin.

Digestive System. — The mouth is situated

in the middle of the tentacular disk (PL 41.
fig. 3 c), and is closeable in the Hippocrepia
by an epiglottis-like hollow valve (epittom&)t
which is absent in the Infundibulata; at the
base of this valve is an aperture which per-
forates the disk to open into the abdominal
cavity. The mouth terminates in a pharynx
(PL 41. fig. o e, /), and oesophagus (tig.* 18,
6, d), often of considerable length, which i.s
sometimes succeeded by a strongly muscular
gizzard. Next comes the stomach (tigs.
5 e, b, 18 /), often very capacious, and
with an appendix (fig. 18 e), and finally the
intestine (fig. 18 g), which terminates out-
side, but close to the disk (fig. 5e} c). Thus
the alimentary canal is bent upon itself, the
two orifices being very near each other.

The alimentary canal consists of three
coats — an inner rugose, composed of cells
with brownish contents, and representing a
liver; a middle, composed ol colourless
nucleated cells ; and an outer, thin, cellular
coat, probably containing muscular fibres.
The mouth and more or less of the upper
portion of the alimentary canal are ciliated.

The walls of the cavity of the abdomen,
the interior of the disk and of the tentacles
all communicate, and are filled with a clear
liquid, in which irregular particles float,
and in which a constant rotatory motion
exists, produced partly by muscular action,
and partly by cilia. This liquid corresponds
to a chylaqueous iluid, and performs the
chyliferous, sanguiferous, and respiratory
functions ; for there are no distinct respira-
tory organs, nor blood-vessels.

The muscular system is well developed,
the fibres being transversely striated — the
principal, or retractors, arising from the
bottom of the cells, and being inserted into
the sides of the oesophagus, so as to exert
a retracting action upon the body. There
are also parietal rnusdes, which are in the
form of circular bundles running transversely
round the cell; they project the polypide.

The nervous system consists of an oval
ganglion placed between the oral and anal
apertures, and giving oft' branches to the
tentacles, alimentary canal, &c. ; and there
is stated to be a nervous connexion between
all the cells of a zoarium, called the colonial
system.

Reproduction. — The Polyzoa are propa-
gated by gemmation, and by the agency of
sexual organs.

Two kinds of gemmation occur. In the
first, the gemmae are developed externally
from the parent cells, and usually near the

POLYZOA.

[ 627 ]

PONTIA.

orifice, but often from the stem ; these
gemmae, on attaining their full development,
remain attached to the parent, thus forming
the compound organism. In the second,
they are formed internally, as buds upon
the fimiculus, which is a process passing
from the testis to the stomach. Afterwards
they become free within the abdominal
cavity, from which they escape at an orifice
near the disk, according to Beneden, al-
though this is denied by Allman. The
latter kind, which are often called ova,
have an external hard coat, exhibiting the
appearance of a marginal ring, and are often
of a dark colour ; their development is not
dependent upon impregnation, and they
seem to correspond to the winter ova of the
Entomostraca &c. : Allman proposes the
name statoblasts for them. The sexual
organs, which usually exist together in the
same individual cell, consist of a roundish
ovary, attached by a short peduncle near
the orifice of the cells ; whilst the testis is
a rounded irregular mass attached to the
funiculus. The ova, which are first set free
in the abdominal cavity, are ciliated and
swim freely.

Four modes of reproduction in the Poly-
zoa have been described, three of them
taking place in an asexual way :— 1. The
growth of the whole colony by buds which
are external ; 2. The reproduction by eggs
formed by internal buds of the endocyst ;
3. The production of new polypides and
eggs in empty cells (zooecia), by brown
bodies which are produced out of the
former polypide of the cell by retrogressive
metamorphosis j 4. Sexual reproduction by
eggs and spermatozoa.

The Polyzoa are divided into two orders :

Order I. HIPPOCBEPIA (PhylactoUemata).

Tentacular disk horse-shoe shaped or bi-
lateral; mouth with an epistome; mostly
freshwater.

Order II. INFUNDIBULATA (Gymnolcemata).

Disk circular, or nearly so ; epistome ab-
sent ; mostly marine. 3 suborders :

Cyclostomata. Cells with a simple round
orifice.

Clieilostomata. Orifices of cells fitted
with a thin, membranous or calcareous
plate ; with a curved mouth, furnished with
a moveable lip.

Ctenostomata. Orifices surrounded by a
circle of setae.

BIBL. Johnston, Br. Zooph. 253; Busk,
Mar. Polyzoa, Brit. Mus. ; Fossil, Pal. Soc.
1859; Farre, Phil Tr. 1837; Dumortier
and Beneden, Mem. Ac. Brux. 1850 ; Han-
cock, Ann. N. H. 1850, v. ; Allman, Freshw.
Polyzoa, Ray Soc. ; Gosse, Mar. Zool ii. 1 ;
Miiiler, Wieg. Archiv, 1860, 311; Huxley,
Invertebr. ; Smitt, Qu. Mic. Jn. 1871, 155 ;
Miiiler, Reich, fy D. ReymendSs Ai'chiv,
1860; Claparede, Sieb. $ Koll Zeit. 1871,
137; Norman, Qu. Mic. Jn. 1868, 212;
Hyatt, Pr. Essex Institute, U. S. A. 1868 ;
Nitsche, Sieb. $ Koll Zeit. 1870; Barrels,
Embryol. 1877 ; Hincks, Polyzoa, 1880.

POM'PHOLYX, Gosse.— A genus of
Rotatoria, family Brachionaea. P. compla-
planata ; freshwater. (Gosse, Ann. N. H.
1851, viii. 203.)

POMPHOLYX'OPHRYS, Archer, Hy-
alolampe, Greef. — A genus of freshwater
Rhizopoda.

Char. Rhizopod composed of two distinct
sarcode regions, the inner a dense coloured
globular sarcode mass, the other colourless,
and bearing a number of separate hyaline
globular structures ; these are disposed in a
layer around the inner globe, which latter
gives off slender non-coalescing pseudopodia.
BIBL. Archer, Qu. Mic. Jn. 1870, p. 105.
PONTEL'LA, Lubb.— A genus of Cope-
podous Entomostraca. P. Wollastoni, Wey-
mouth. (Ann. N. H. 2. xx. 406; Brady.
Cop. i. 73.)

PON'TIA, Fabr.— A genus of Lepidopte-
rous Insects, of the family Papilionidae.

This genus contains some of the com-
monest butterflies, as P. brassicce, the large
cabbage-butterfly ; P. rapa, the small cab-
bage-butterfly; and P. napi, the green-
veined white" butterfly.

The form and structure of certain scales
existing upon the under side of the wings
of the males are curious ; and the markings
were formerly found so difficult to render
distinct, that the scales were used as test-
objects.

In the male P. brassicce the upper surface
of the anterior wings is free from spots,
whilst in the female there are two black
spots in that situation. The peculiar scales
are represented in PI. 34. fig. 24; fig. 26
exhibits a portion of the wing with the
ordinary scales.

In P. rapce and P. napi the anterior wings
of the males have a single spot upon the
upper surface, whilst there are two upon
each wing in the females. The peculiar
scales bear considerable resemblance in the

2s2

PONTOCYPRIS.

[ 028 ]

PORPHYRIDIUM.

two species (PI. 34. fig. 23 a, scale of P.
rapes ; fig. 23 6, portion of wing, showing
the points of attachment of the two kinds
of scales).

The scales may be separated by gently
pressing the under surface of the wings
against a slide.

See SCALES of INSECTS and TEST-OBJECTS.

BIBL. Westwood, Brit. Butterflies.

PONTOCY'PRIS, Sars.— An Ostracode,
near Argillcecia among the Cyprida, with
fragile pod-like valves, higher in front than
behind ; no branchial appendage on the
second pair of jaws ; upper antennae long
and setiferous. 3 British species, rather
common.

BIBL. Brady, Linn. Tr. xxvi. 384.

POPPY.— The seeds of Poppies (Pa-
paver, L., Nat. Order Papaveraceae) are ele-
gant opaque objects under a low power, the
testa being pitted so as to produce a reticu-
lated surface (PI. 39. fig. 14).

PORCELLID'IUM, Claus.— A genus of
Copepoda. 4 species, among Laminariee,
&c. (Brady, Copep., Ray Soc.)

PORIF'ERA. See SPONGIDA.

POROCYC'LIA, Ehr.—A genus of Dia-
tomaceae closely allied to LIPAROGYBA.

BIBL. Pritchard, In/us. 823.

PORODIS'OUS, Grev.— A g;enus of Dia-
tomaceae, fam. Melosirse. (Rabenht. Alq. i.
35 ; Greville, Mic. Tr. 1863, 63 ; 1865, 46.)

PORO'NIA, Fr.— A genus of Spheeriacei
(Ascomycetous Fungi), consisting of a corky
stroma, which is flat or hollowed out at the
top, and studded with the ostiola of the
perithecia. The only British species is not
uncommon on horse-dune:.

BIBL. Fr. Syst. Myc. li. 330 ; Berk. Outl
385; Cooke, Handb. 791; Tul. Carp. ii.
27, t. iii.

POROSPELE'RA, Steinm. — Small glo-
bular fossils, common in the chalk, known
as Orbitolinte, formerly referred to Sponges
and Foranainifera, now found by Carter and
Steinmann to have Hydractinian structure ;
calcareous, with reticular tissue and radiate
tubes. (Steinrnann, Palceontographica, 1878,
xxv. 120.)

POROUS STRUCTURES OF PLANTS.
— What are ordinarily called porous tissues
in vegetable anatomy are described in ac-
cordance with their real nature under the
head of PITTED STRUCTURES. True pores
do, however, occur in the walls of vegetable
cells, from secondary or ultimate changes in
their character. They are seen in the cells
of the leaves of Leucobryum and Sphagnum

(see SPHAGNACE.&:). Other regular orifices
are produced in the walls of the cells of
many of the zoospore-producing Confervtc,
as Conferva, Cladophora, Enter omorpha, &c.
(see PI. 9). The wall of the sporangial cell
of Achlya presents analogous openings ; and
according to Cohn, pores are produced in
the spore-cells of SPHJEROPLEA to admit
the spermatozoids. The pits and the inter-
stices between reticulated fibrous secondary
deposits are often changed into true holes
in old cells, but this is the result of decay
of the primary membrane ; it takes place
very early however, at the contiguous ends
of SpiRAL-fibrous and PITTED CELLS coa-
lescing to form ducts, changing the septum
formed by the adjoining ends into a kind of
grating, or irregularly torn diaphragm.

PORPE'IA, Bail— A genus of Diato-
maceae, closely allied to BIDDULPHIA. Gulf-
stream.

BIBL. Pritchard, Inf. 350 j Rabenht,^.
i. 315.

POR'PHYRA, Ag.— A genus of Por-
phyraceae (Florideous Algae), with an ex-
panded, membranous, shortly-stalked frond,
composed of a single layer of cells approxi-
mated in fours, the contents purple or red.
Fructification consisting of: — 1. scattered
sori of oval spores ; 2. octospores immersed
in the frond ; and 3. antheridia, on the
same or distinct plants. P. laciniata and
vulgaris are common on our coasts.

BIBL. Harvey, Mar. Alg. 261, pi. 25 A ;
Thuret, Ann. Sc. Nat. 4. iii. 6 ; Janczewski,
Mem. Soc. Cherbourg, xvii. 345.

PORPHYRA'CE^E.— A tribe of Flori-
deous^ Algae (according to Thuret), of low
organization, forming Ulvoid membranous
fronds or strata of Confervoid filaments, of
a purple or red colour. They are placed
among the Ulvaceae by most authors, but
differ in the absence of the zoospores and
the presence of tetraspores (octospores) and
antheridia. They are marine, — Porplyra
growing on rocks and stones, Bangia the
same, or parasitic upon Zostera, Algte, £c.

British Genera.

Porphyra. Frond plane, membranous,
very thin, of a purple colour, with oval
spores in sori, and tetraspores (square)
scattered all over the frond.

Bangia. Frond filiform, tubular, com-
posed of numerous radiating cells in trans-
verse rows, enclosed within a continuous
hyaline shea th.
PORHPY RID'IUM = Palmella cruenta.

POKRIGO.

[ 629 ]

TOTTIOJDE^.

PORRI'GO. SeeFAvus.

POTAMOOY'PBIS, Brady.— One of the
CypridfB ; valves reniform, thick, right
larger than left ; upper antennae with very
short setae ; post-abdominal rami rudimen-
tary. 1 British species.

BIBL. Brady, Nat. Hist. Tr. North. $
Durham, iii. 365.

POTASH, AND ITS SALTS.

Caustic Potash.— The strength of the
solution may be that of the Liq. Potasste
of the Pharmacopoeia. But we prefer a
stronger solution made with 1 drachm of
the potassa fusa or stick-potash of the
shops, and 1 fluid oz. of water. The solu-
tion should be allowed to settle, and the
clear portion poured off into one of the
test-bottles (!NTR, p. xxvii).

Some remarks are made upon the action
of potash in the INTR,, and others under
the heads of the tissues, &c. On treating
organic substances with this reagent, the
cystic-oxide-like crystals of the carbonate
(PI. 10. fig. 26) will frequently be formed.

Chromates of Potash. — The bichromate is
used in the preparation of the chromate of
lead for injection. Its crystals polarize
well. The neutral chromate is also some-
times used for preparing injections. See

PREPARATION.

Nitrate of potash, nitre, or saltpetre. —
This salt is dimorphous : it usually crystal-
lizes in six-sided prisms with dihedral sum-
mits, or in other forms belonging to the
right-rhombic prismatic system. But some-
times it assumes the form of obtuse rhom-
bohedra, resembling those of nitrate of soda,
and referable to the rhombohedric system.

The crystals exhibit very beautifully the
phenomena of ANALYTIC CRYSTALS.

POTATO-FUNGUS. See BOTRYTIS.

POT'TIA, Ehr.— A genus of Pottiaceous
Mosses, including some of the Gymnostoma
and Weissice of Hedwig and others. Wilson
separates as Anacalyptce the species with a
peristome (fig. 606).

Fig. 606.

POTTIA'CE^E.— A tribe of Pottioi

Pottia caespitosa.
Fragment of peristome.
Magnified 50 diameters.

Synopsis of Genera.

Pottia. Calyptra dimidiate. Peristome
simple or wanting ; if present, composed of
lanceolate articulate teeth, simple or with a
longitudinal line, rugulose and somewhat
fleshy.

Trichostomum. Calyptra dimidiate. Peri-
stome simple, sixteen teeth, each split to the
base into two cilia, or irregularly and there-
fore into more than two, erect, stiff, and
not twisted.

Barbula. Calyptra dimidiate- hood -
shaped. Peristome simple, ciliiform ; cilia
thirty-two, solitary or approximated in
pairs on a more or less exserted basilar
membrane, split into two cilioles behind,
very long, articulate-rugulose, twisted to
the' left, rarely to the right, in one or several
spires, hygroscopic. Cells of the operculum
and calyptra twisted in the same way.

Ceratodon. Calyptra dimidiate. Peri-
stome simple ; teeth sixteen, connate at the
base into a cellular membrane, split into
two long, nodosely articulated dark-coloured
arms, paler on each side, densely trabeculated
at the lower part. Capsule thick-skinned,
shining, nodding, with a somewhat nodose
collum; annulate.

Weissia. Calyptra dimidiate. Peristome
simple or wanting ; if present, composed of
sixteen lanceolate or subulate, entire or
cribrose, equidistant teeth.

POTTIOI'DE^E.— A family of Acrocar-
pous operculate Mosses, but sometimes
Pleurocarpous by innovating branches.
Leaves of varied form, with a terete nerve ;
cells parenchymatous, hexagonal or squa-
rish six-sided, looser at the base, sometimes
very lax, more or less pellucid, often ex-
ceedingly transparent, large, fragile, rigid,
foraminate, bearing on the upper side soli-
tary papillae or confluent papillae (hence
often truncate and tuberculate at the apex),
placed in the middle of the cell ; cells
mostly full of chlorophyll, often very small
and thickened. Capsule erect, rarely in-
clined, oval, elliptic or pear-shaped oblong,
smooth or striate, the operculum mostly
conical or beaked.

This family is divided into three tribes :

CALYMPERACE^E. Basilar cells of the
leaves rigid, hyaline, often very brittle,
more or less ample, empty, distinctly fora-
minated.

POTTIACE^E. Basilar cells of the leaves

PRASIOLA.

[ 630 ]

PREPARATION.

soft, pellucid, longer, mostly empty, rarely
containing a persistent primordial utricle.

ORTHOTRICHACEJE. Basilar cells of the
leaves with only the very lowest soft, the
upper mostly thickened, rarely pellucid and
normal.

PRASPOLA, Meneghini.— A genus of
Ulvacese (Confer void Algee), separated from
Monostroma by the arrangement of the
quadrigeminate cells of the frond in lines,
with wide intercellular walls ; from Ulva
by the existence of only a single layer of
cells, and from both by the absence(?) of
a reproduction by zoospores ; from Schizo-
yonium by the frond consisting of expanded
plates. The species are included under
Ulva (the terrestrial forms) in the 23r. Flora
and Harvey's Alga, ed. 1. They have been
carefully examined by Jessen, who finds
the fronds proliferous at the margins ; the
tf spores " he describes as consisting of mo-
tionless cells formed of the entire contents
of the ceUs of the frond, set free by the
solution of the parent cell. The reproduc-
tion of this group seems to us to require
further investigation. Jessen includes here
P. cdtophytta (PI. 3. fig. 19), crispa,fur-
furacea, and a form which he names P.
stipitata, differing from the last chiefly
in the narrowly wedge-shaped, stipitate
character of the frond : probably the last
three constitute only varieties of one species.

BIBL. Jessen, Prasiola Money. 1848;
Harvey, Br. Aly. 171 ; Hassall, Alg. 297,
pis. 77, 78 ; Kiitz. Sp. Aly. 472 ; Rabenht.
Aly. iii. 308.

PREPARATION of microscopic objects
for examination and preservation. — Some
remarks on the former point will be found
in the INTRODUCTION, p. xxxii ; and under
many of the general and special articles,
such as Diatoruaceae, Ovule, &c., directions
are given. A few general remarks may
still however be made in this place.

The parts of bodies or objects are usually
separated by the mounted needles under a
dissecting microscope, or by means of sec-
tions, according to the nature of the views
which it is desired to obtain. With regard
to the former operation, it need be merely
observed that it is generally to be per-
formed under water, in a watch-glass, glass
cell, or other convenient holder.

The preparation of sections is a more
complicated process. Soft parts of animals
are best sliced by means of a Valentin's
knife ; but firmer structures, such as horn,
may be cut with a sharp razor. Vegetable

structures in general are^ sliced with a
razor, which must be kept very sharp, and
rubbed on a strop frequently while in use,
and always before putting away. Fresh
stems, thick leaves, &c., may be simply
held in the fingers ; thin objects, such as
leaves, petals, &c., are best placed in a split
cork or piece of carrot, the halves of which
are kept together by insertion in the neck
of a vial or a test-tube, which at the same
time serves as a handle. Sometimes it is
advantageous to immerse objects, especially
soft or very small ones, in thick mucilage
of gum-arabic, and to allow this to dry
until tough enough to be cut by the razor ;
the slices are freed from gum by immersion
in water. Dry objects, such as wood, dried
leaves, seeds &c., must be softened by soak-
ing in water before slicing. Small firm ob-
jects, such as softer seeds, are mostly sliced
when fixed in a bit of white wax or
stearine, which may be done by placing
them on the surface of the latter, and
stirring them into the substance melted by
the application of a hot wire. Most sec-
tions of vegetable objects are obscured by
air-bubbles engaged in the intercellular pas-
sages, &c. In old wood and similar objects
immersed in liquid, the air is readily driven
out by heat; in fresh structures, where
heat may coagulate or dissolve matters, the
air may be allowed to dissolve or escape by
itself, which requires time, or it may be
removed by exhaustion under an air-puinp.

Sections of wood, &c., which are to oe
mounted in liquids, should be soaked for
some little time in spirit or turpentine, to
remove resins, &c. The Section-cutter is
used for slicing such objects; but this is
not of much use except when large numbers
of very perfect sections of the same kind
are required for purposes of sale, &c.

It need scarcely be said that sections
require to be made in various directions in
studying objects bv these means. Thus
stems should be sliced horizontally, and
perpendicularly both parallel and at right
angles to the medullary rays. When work-
ing with high powers, it is necessary to be
on our guard against appearances of stria-
tion or fibres which may be produced by the
fine notches in the cutting instrument.

The structure of laminated shells, &c.,
may often be seen in fragments broken off
by the point of a knife. But sections of
bone, shell, &c., are best made bv sawing
off thin pieces with a frame-saw having a
watch-spring blade, grinding them down

PREPARATION.

[ 631 J

PRESERVATION.

upon a water-of-Ayr or some other stone, i
and polishing: them upon a clean leather
hono or strop with putty -powder and
water, finally upon a dry hone alone.

Sections of very hard substances, as
agate, &c., are so easily made by jewellers,
that a description of the process is scarcely
necessary. They are cut by means of a j
rotating* circular iron plate, its margins
being coated with a mixture of oil and
diamond-dust. They are then ground upon
a plate of metal with emery-powder and j
water, and polished upon a flat surface of j
pitch with putty-powder and water.

In grinding and polishing sections of
hard structures, it is often requisite to
cement them to a slide with Canada bal-
sam, heat being applied until tiia balsam
has become so hard as to iix the section
firmly to the slide. As soon as one side
has been polished, the section is removed !
from the slide, the balsam being rendered
soft by heat, the polished side cemented to
the glass, and the other side polished. The
balsam may afterwards be separated from
the section by maceration in oil of turpen-
tine, benzole, &c.

The more delicate animal tissues require
hardening before section. This is usually
produced by freezing in the section-cutter ;
or by maceration in chromic-acid mixture
(15 grs. of chromic acid to the pint of
water, with £ a pint of methylated spirit),
bichromate of potash (180 grs. to the pint),
osmic acid, or Miiller's liquid (composed of
220 grs. of bichromate of potash, 90 grs. of
sulphate of soda, and a pint of distilled j
water). These liquids require to be poured
oft' and replaced until the tissue is suffi-
ciently hardened.

Great care is required in the interpreta-
tion of the appearances presented by minute
objects or portions of tissue, as to the
influence of the liquids in whieh they are
immersed ; even water often totally distorts
then* natural appearance, as in the case of j
pollen, &c. And in animal tissues, the
liquid of the allantois, blood-serum, or
iodized serum or albumen (p. 441), are
often useful as corresponding nearly to the
liquid in which they are naturally im-
mersed, and so producing but little change.

Besides these methods of preparation,
there are those which enable the observer
to keep sections or minute plants and animals
under continuous examination without be-
coming dry, to provide a proper and equable
or even higher temperatures to parts or the

whole of organisms, and to add gases to the
fluid surrounding the object. Reckling-
hausen's moist chamber fulfils the first
requirement ; and Strieker's slide, which is
heated by means of the galvanic current, is
most useful in producing constant amounts
of heat. Strieker's gas-chamber, slide, and
its conducting tubes enable carbonic acid,
oxygen, hydrochloric acid, or any other gas
to be applied to the fluid under examination.
A substitute for those complicated pieces of
apparatus, may be made by procuring a flat
strap-shaped piece of metal, to be fixed upon
the stage, with an aperture near one end corre-
sponding with that in the stage. The slide
is placed upon this, and a feeble flame of a
spirit-lamp applied to the other end, will
serve to produce the gentle heat required to
set in motion or continue the amoeboid
movements of organisms.

The preparation of many objects requires
the process of dyeing or STAINING.

BIBL. Beale, flow fyc. ; Carpenter, Mi-
croscope ; Frey, Mikr. ; Strieker, Hist. ;
Gerlach, ibid. ; Rutherford, Hist. ; Mouchet,
Mn. Mic. J. iii. 75; Fletnrning, Schultze's
Archiv, ix. 123 ; Gronland, Cornu, and
Rivet, Prep. Micros. (Botanical), 1871, Qu.
Mic. Jn. 1872, 82; L. Clarke, Phil. Tr.
1851 ; Minot, Mn. M. J. xviii. 97 ; Meyer,
Arch. Mik. An. xiii.; Moseley, Qu. Mic. Jn.
1872, 374, 379; Pritchard, Qu. Mic. Jn.
1872, 380; Ranvier, Hist, tech.-, Marsh,
Section-cutting ; Betz, Schultze's Archiv, ix.
101 ; Qu. Mic. Jn. 1873, 343 ; Gibbs, Hist.
1880.

PRESERVATION of microscopic ob-
jects.— Under this head we shall consider
the arrangement of microscopic objects for
permanent preservation, supposing that they
have been prepared (PBEPABATION) in
such manner as to render this possible.

Dry objects, or those which exhibit their
structural peculiarities in the dry state. —
These are sometimes mounted alone, at
others when immersed in some preservative
compound.

In the dry and uncovered state, they are
occasionally mounted upon disks of cork,
leather, or pasteboard, the surface upon
which the object is to be placed being black-
ened by a coating of very fine lamp-black
mixed with warm size or gum-water, or by
a piece of dull black paper pasted upon it ;
the simplest way of making the disks is to
paste black paper upon thick soft leather,
and cut out the disks with a punch, like gun-
wads. The object is fastened to the disk with

PRESERVATION.

[ 082 ]

PRESERVATION.

a little solution of marine glue in naphtha,
or with gum. The disks are sold in the
shops. They are usually transfixed with a
])in, by which they may be fixed in the
forceps under the microscope, and may be
fastened to the bottom of a box lined with
sheet-cork when not in use. The advantage
of this plan is its simplicity ; its greater dis-
advantage, however, is that the objects are
liable to injury, and become covered with
dust. It answers very well for common
objects, seeds, minute lichens, &c. ; but
when the objects are of value, they should
be mounted in a cell.

The cell may be made of a square piece
of card-board or pasteboard, of suitable
thickness, with a hole punched in the mid-
dle, fastened to a slide by marine glue or
Canada balsam — the object being fixed to
the slide by a little of either of the above
cements, and a thin glass cover cemented to
the card-board. Or the whole may be fast-
ened together with paste — first a piece of
black paper upon the middle of tne slide,
then the perforated square, next the object,
and lastly the cover. The square of paste-
board may be replaced by a glass ring, a
perforated square of glass, or a piece of
sheet gutta-percha.

When the objects are minute or very
thin, the square of pasteboard may be dis-
pensed with, and they may be mounted thus :
they are to be laid upon a slide, and a cover
of thin glass placed upon them ; a piece of
paper larger than the cover, with a portion
cut from the middle larger than the object,
is then covered with paste, and a minute or
two allowed to elapse, that the paper may
become thoroughly imbued with it, the
superfluous paste being removed with the
paste-brush; the paper with the pasted side
downwards is then laid upon the cover and
the adjacent portions of the slide, and gently
pressed with a cloth, that it may be accu^-
rately applied to the glass surfaces. The
whole is then allowed to dry. The principal
point in this process is the complete removal
of the superfluous paste before the paper is
applied. If this be not effected, it will be
drawn by capillary attraction between the
cover and the slide, and reaching the object,
will spoil it.

A very secure method of mounting dry
objects which are not altered by heat, con-
sists in laying a ring or square of black
japan upon a slide, the thickness of the
layer being adapted to that of the object,
and applying a pretty strong or long-con-

tinued heat until the cement becomes per-
fectly hard when cold. The object is next
placed within the ring, a cover laid on, and
heat applied until the cement becomes liquid.
Gentle pressure then brings the cement and
the margins of the cover into contact ; and
when the cement becomes cold, the cover is
firmly fixed to the slide.

Another method of fastening the cover to
the slide is by the use of electrical cement
and balsam (CEMENTS, p. 150) mixed with
1 or 2 parts of tallow.
Many dry objects can be well preserved by
Mounting in Canada Balsam. — When this
is to be done, care must be taken that they
are thoroughly dry ; otherwise they will ac-
quire a milky appearance, from being sur-
rounded by minute drops of water. Some
objects in drying curl up or become de-
formed, although their minute structure
may not be essentially changed ; this may
be prevented by confining them between
two slides tied together with thread, or held
together by india-rubber rings, sealing-wax
applied at the two ends, or by a folded strip
of orass with the ends riveted. If the ob-
jects be of tolerable size, they are then
soaked in oil of turpentine kept in an oint-
ment-pot covered with a lid, for some hours,
or even days, until the air is entirely dis-
placed from them by the turpentine. The
latter will often also remove the colouring-
matter from some objects, as parts of insects,
which may or may not be desirable ; hence
the duration of the process must vary
accordingly. A clean slide is then warmed
over the flame of a spirit-lamp, or upon a
stove, and some clear balsam placed in the
middle of it, and rendered more liquid by
further gentle heat; the object is next care-
fully removed from the turpentine with for-
ceps, drained and laid upon the warm
balsam. Some more balsam is then allowed
to fall from the warm wire (BALSAM)
upon the object ; and when this is well
covered with it, a warmed cover is gently
laid upon its surface. The superfluous bal-
sam then escapes at the sides of the cover ;
and this should be aided by gentle pressure.
The slide is next maintained at a gentle heat
upon a warm mantelpiece, or a piece of tin-
plate, until when allowed to cool, the bal-
sam is perfectly hard. As soon as this is
the case, the superfluous portions are cut
away or scraped off" with a knife, the sur-
faces of the glasses cleaned from any residue
by a cloth wetted with turpentine or ben-
zole, and some sealing-wax varnish applied

PRESERVATION.

[ 633 j

PRESERVATION.

to the edges of the cover and the adjacent
portions of the slide.

The success of the operation depends
mainly upon two circumstances, viz. the
object having been thoroughly dried, and
the exclusion of air-bubbles. The former
constitutes no difficulty, time being all that
is required ; but the latter requires that the
object shall previously have been thoroughly
moistened with the turpentine, and that the
balsam shall have been added to the object,
when laid in the balsam uj)on the slide,
before so much of the turpentine has evapo-
rated as will allow air to enter any minute
cavities in the object. The heat applied
should also be gentle ; and if the direct flame i
of a spirit-lamp be used, its application
should be made rather to some portion of
the slide near that upon which the object is
placed, than directly beneath the object. If
much heat be applied, bubbles of the vapour
of the turpentine will often disfigure the
object for a time; but these will vanish as
the object becomes cool.

If air-bubbles have found their way into
the object, the slide must be macerated in
oil of turpentine until the balsam is dissolved
and the object liberated, and a fresh mount-
ing made.

If the object be large, it must be mounted
in a cell. A glass ring (sold in the shops)
of suitable thickness must first be cemented
to the slide by balsam; more balsam is
then added until the cavity is filled, the
object next added, and the cover applied.

If the object be minute, its removal for
maceration in the turpentine is not requisite,
and might entail the loss of the object. It
must then be laid upon a slide, a drop or
two of turpentine added, and the whole
warmed until no air-bubbles are visible.
The cover is then removed, most of the tur-
pentine drained off, balsam added from the
warmed wire, and the cover applied as be-
fore : or balsam niav be placed upon the slide
near the margin of the applied cover ; and
on applying a continued gentle heat it will
find its way under the cover, and replace
the turpentine as it evaporates.

If air-bubbles remain in parts of a minute
object, a cover should be applied, turpentine
added, and the slide held over a lamp until
the turpentine boils, and the bubbles dis-
appear on cooling. The cover is then re-
moved, most of the turpentine allowed to
evaporate, the balsam added, and the cover
re-applied. Gum dammara may be used
in the same manner as Canada balsam.

Gum and Glycerine. — Objects which can-
not be conveniently dried may be mounted
in a solution of gum-arabic in glycerine ;
the manipulations are much the same as
with balsam, except that no heat is re-
quired. Glycerine jelly is often used.

Mounting in Liquid. — The structure of
many objects is so altered by drying that
they require to be mounted in some preser-
vative liquid. These, if of considerable size,
must be mounted in glass cells.

The cells may consist of glass rings, i. e.
portions cut transversely from pieces of glass
tubes, of various sizes, according to the
dimensions of the objects. In using these,
the ring is first warmed in the flame of a
spirit-lamp, being held by steel forceps ; one
of the ground surfaces of the ring is then
covered with marine glue or balsam pre-
viously melted in the same flame ; the sur-
face of the slide to which the ring is to be
cemented is then heated in the flame, and
whilst it is hot the surface of the ring coated
with the melted cement is applied to it, and
the ring pressed firmly, so as to displace
the superfluous portions. When cold, these
are to be removed with the point of a knife;
sometimes a little solution of potash, oil of
turpentine, or naphtha is required for this
purpose. The cell is then complete, ex-
cepting the lid or cover, which consists of
a circular plate of thin glass, of slightly less
diameter than that of the outer margin
of the glass ring. The cell is now to be
filled with the preservative liquid, the object
placed in it, and the cover applied, being
made to slide over the upper surface of the
ring, so as to displace any excess of liquid,
and prevent the admission of air-bubbles.
If the quantity of liquid first put into the
cell be not sufficient, more must be added,
until slight excess is present; the superfluous
portions may be removed by a piece of blot-
ting-paper, and the margin of the cover and
ring very carefully wiped clean with a silk
handkerchief, so that the surfaces may be
free from all traces of the preservative liquid.
The exposed parts of the upper surface of
the glass ring, and the adjacent margins of
the cover, are then to be coated lightly with
one of the liquid cements, by means of a
camel's-hair pencil ; and when the first coat
is dry, another must be laid on, so that the
edges of the cover and the adjacent parts of
the glass ring may be firmly cemented toge-
ther, and the cell completely closed, to pre-
vent the evaporation or the contained liquid.
The important points in this process are,

PRESERVATION.

[ 634 ]

PRESERVATION.

that the heated cement used to fasten the
ring to the slide must accurately coat every
portion of the two surfaces in apposition,
and that the surfaces to which the liquid
cement is applied must be perfectly clean
and dry, so that the cement may come into
contact with the surfaces of the glass.
Rings of India-rubber and gutta-percha are
very useful instead of glass.

When the objects are very large, the
rings may be conveniently replaced by cells
constructed of slips of glass, arranged so as
to constitute four sides of a box, the bottom
of the box being formed by the slide, and
the top by a plate of thin glass : the pieces
should be cemented together by marine
glue.

Smaller cells may be made with marine
glue, melted, dropped upon a slide and flat-
tened whilst warm with a piece of wetted
glass, the superfluous portions and central
portion cut away with a knife. Should the
marine glue become loosened from the slide,
it may be re-fastened by heat ; and if the
upper surface be not perfectly flat, it may
be made so by grinding with emery-powder
and water upon a plate of metal or upon a
stone.

Minute objects may be mounted in liquid
in a variety 'of ways, the choice of which
will vary with their nature. They are
generally mounted in shallow cells, the
sides of which are formed by varnish.

The old method consisted in placing
the object upon a slide, adding a drop or
two of the preservative liquid, applying the
glass cover, adding more of the liquid, or
removing excess with blotting-paper, until
the space between the slide and cover was
accurately filled, then applying to the mar-
gin of the cover and the adjacent portions
of the slide a coat of some liquid cement, as
gold-size, asphalt solution, black japan, &c.
Objects thus mounted keep well for a time;
but the cement soon apparently runs into
the space between the cover and the slide,
and the object becomes spoiled. It is often
requisite, however, to mount an object in
this way, which may be lying upon a slide,
perhaps in some peculiar position which it
is important for it to retain ; when this is
the case, the electrical cement with balsam
and tallow should be used; and there is less
fear of change, provided spirit be not used
as the preservative liquid.

Whenever it is possible, then, a cell- wall
should be previously formed, by laying a
ring or square of one of the liquid cements

upon the slide with a camel's-hair pencil,
and applying a continued heat until it be-
comes thoroughly hard when cold. The
cements generally used aro : — asphalt solu-
tion ; gold size with which a little finely
powdered litharge has been well mixea,
immediately applied, as it soon hardens ;
sealing-wax varnish ; solution of marine
glue in naphtha, or of Canada balsam in
benzole or chloroform, or the balsam alone.
Allport's liquid marine glue is very useful.
If the upper surfaces of the rings or squares
formed of these compounds, when thoroughly
dry and hard, be not perfectly flat, they
may be made so by grinding alone, or with
emery and water, upon a piece of metal,
marble, or a stone. The object is then
placed in the cell, the preservative liquid
added, and the cell closed as above de-
scribed.

The following are the most important
preservative liquids and compounds : —

Thwaites's liquid is thus prepared : to
16 parts of distilled water add 1 part of
rectified spirit, and a few drops of creosote
sufficient to saturate it; stir-in a small quan-
tity of prepared chalk, and then filter. With
this liquid mix an equal measure of camphor-
water, and before using, strain through fine
muslin. Used for preserving freshwater
Algae, as having but little action upon the
endochrome.

Haifa's liquid. — Prepared with bay-salt
and alum, of each a grain, distilled water
1 oz. ; dissolve. Forms a readily prepared
substitute for the former in the preservation
of the Algae (Desmidiacese).

Hantzsch, quoted by Carpenter, produced
a fine preservative medium for minute
A.lgae ; composed of 3 parts of alcohol, 2 of
distilled water, and 1 of glycerine ; and the
object, laid in a cement-cell, is covered with
a drop, and placed under a bell-glass. Al-
cohol and water evaporate, and leave the
glycerine: more is added time after time,
and the cell is thus filled.

Acetate of alumina. — 1 part of the salt to
4 parts of distilled water. Topping finds
this the best preservative for delicate vege-
table colours.

Distilled water. — Very often us°d for
preserving Algae ; but perhaps camphor-
water would be better.

Camphor-water is prepared by digesting
distilled water with a lump of camphor.

Spirit and water. — Proof-spirit is prepared
by mixing 5 measures of rectified spirit
with 3 of distilled water. It is frequently

PRESERVATION.

[ 035 ]

PRESERVATION.

used for preserving' animal structures, or-
gans, injections, &c. Delicate preparations
may "be kept in a mixture of 1 part of
spirit with 5, or even 10, parts of water,
Dilute spirit should never be used as a pre-
servative when it can possibly be avoided,
on account of its action upon the cements.
Methylated spirit is very useful, on account
of its cheapness and strength ; may be used
when diluted in preserving large specimens
of animal tissue.

Creosote water is prepared by filtering a
saturated solution of creosote in rectified
spirit, mixed with 20 parts of water. It is
recommended for preserving preparations of
muscle, cellular tissue, tendon, cartilage, &c.
Arsenious acid. — A preservative liquid is
made of this substance by boiling excess of
the acid with water, filtering the solution,
and adding 2 parts of water. It is a very
good preservative of animal tissues. Arse-
nite of potash, 1 part dissolved in 160 of
water has been found useful for preserving
the primitive nerve-tubes.

Corrosive sublimate. — A dilute solution of
this substance is useful in the case of the
blood-corpuscles, nerve, muscular fibre, &c.
Salt (chloride of sodium) and water, 5 gr.
to the ounce, was long since recommended
for the preservation of tissues, but is not
much used, because fungi are apt to grow in
it, which might, however, be prevented by
saturating it with camphor by digestion.
Corti has found a tolerably concentrated
solution the best preservative for the delicate
structures and nerve-cells of the internal
ear. Carpenter recommends sea-water, with
one tenth part of alcohol and one tenth of
glycerine, for preserving the delicate marine
organisms.

Carbonate of potash. — 1 part dissolved in
from 200 to 500 of distilled water, is a good
preservative of the primitive nerve-tubes.
Solution of acetate of potash is also useful.

Glycerine. — This is the most valuable of
all liquids for vegetable preparations, which
may be closed air-tight or not at pleasure.
Dissections covered with a glass may be
left in it from day to day, remaining un-
changed and always ready for examina-
tion. Objects may be mounted in it, as
with chloride of calcium. It is one of the
most valuable fluids for the preservation
and preparation also of animal tissues.
Camphor- water and naphtha and water may
be added.

Glycerine and Gum (FarranCs com-
pound).— Pure gum-arabic I oz., glycerine

1 oz., water 1 oz., arsenious acid 1^ grain;
dissolve the arsenious acid in the water,
then the gum, without heat, add the gly-
cerine, and incorporate with great care to
avoid forming bubbles.

Gum-water (see CEMENTS). — The solu-
tion should be very thick, so as to flow with
difficulty from the end of a wire. It may
be used like balsam, but without heat. The
residue is very apt to crack when dry ; this
may be prevented by applying a thick coat-
ing of varnish around its margins.

Chloride of calcium (CALCIUM, chloride
of). — Objects may be mounted in this solu-
tion without closing the cell, by pasting
two narrow strips of paper transversely upon
a slide, leaving a greater interval than the
breadth of the object ; the latter is then laid
upon the slide, a small quantity of the solu-
tion added, and a cover applied. The solu-
tion must not touch the paper. The cover
may be fixed to the paper on the slide by
the electrical cement with balsam and tallow.
It is best, however, to close the cell.

Chloride of zinc. This is an excellent pre-
servative of animal tissues for microscopic
examination. It exerts a slight coagulating
action, but this is not sufficient to seriously
impair the peculiarities of the objects, and
large portions of all structures which may
require to be examined should be kept in it.
The ordinary strength is 20 grs. of the fused
chloride to the 1 oz. of water. A lump of
camphor should be kept floating upon the
surface of the solution in the stock-bottle.

Goadby's solutions. — These are of three
kinds. The first (A) is made with — bay-
salt (coarse sea-salt) 4 oz., alum 2 oz., cor-
rosive sublimate 2 grains, boiling water 1
quart. This is too strong for most pur-
poses, and is only to be employed where
great astringency is required to give form
and support to delicate structures.

The second (B) is made with — bay-salt
4 oz., alum 2 oz., corrosive sublimate 4 gr.,
water 2 quarts. This is recommended for
general use, and as best adapted for perma-
nent preparations. Mr. Thwaites uses it for
marine Algae j but we have found chloride
of calcium answer for this purpose, and it is
much more secure. Schultze recommends
it for preserving Medusa, Echiuodermata,
Annelid larvae, Entomostraca, Diatomacese,
Foraniinifera, and Polycystina, both the
hard and the soft parts, and advises the
use of glycerine afterwards to produce
transparence.

When carbonate of lime exists in the

PRESERVATION.

[ 636 ]

PRESERVATION.

E reparations, as in the Mollusca, the fol-
)wing (C) should be used :— take of bay-
salt 8 oz., corrosive sublimate 2 grains,
water 1 quart. Marine animals require a
stronger liquid (D) of this kind, made by
adding about 2 oz. more salt to the last.

Pacini's modification is made with corro-
sive sublimate 1 part, chloride of sodium
2 parts, glycerine 13 parts, and distilled
water 113 parts. The mixture should be
kept for two months ; and in use, 1 part
should be diluted with 3 parts of water, and
filtered. It is good for the preservation of
blood-corpuscles, nerves, ganglia, and
morbid cell-structures.

Salicylic acid. Edwards found that a
saturated solution kept Volvox well.

Deane's compound. — This is made with —
gelatine 1 oz., honey 5 oz., water 5 oz.,
rectified spirit \ ox., and 6 drops of creosote.
The gelatine is soaked in the water until
soft, the honey added, the mixture then
boiled, and when it has cooled somewhat,
the creosote mixed with the spirit added ;
lastly, it is filtered through fine flannel.
This is used warm.

That preservative liquid should always be
chosen which exerts least action upon the
structure of the object which it is requnded
to preserve.

If drying the object does not destroy its
peculiar structure, and the object is not very
transparent, the balsam should be used.

If the structure be destroyed by the pro-
cess of drying, and the object be not impaired
by endosmosis, the chloride of calcium or
glycerine is best. Other circumstances may
render these preservatives desirable: thus
the minute parts of the mouth of the Aca-
rina are best seen and preserved in balsam,
whilst the general form of the body is best
retained when the animals are immersed in
chloride of calcium or glycerine.

Objects to be mounted in a preservative
liquid should be placed in a watch-glass.
If they are alive they maybe placed in water,
and as much of this as possible should be
poured off or removed with a pipette or
blotting-paper, and the preservative liquid
added, and this operation repeated that the
water may be entirely displaced.

The liquid cements used to close the cell
should be applied in several layers, each
being allowed to dry before the next is
applied.

The preservative liquid must not be capa-
ble of exerting any action upon the cements
used in making or closing the cell.

If chloride of calcium or glycerine be used
as the preservative liquid, when the first
coat of liquid cement used to close the cell
has become dry, the slide and cover should
be washed gently with a sponge and di-
stilled water, then dried with blotting-paper
or a silk handkerchief, and the next coat of
varnish applied.

The great difficulty is to permanently
preserve moist objects; for whatever may
be the cement used, watery liquids almost
invariably escape in time, although the pre-
parations may remain good for some years.
No perfect cement is known, which on
thoroughly drying retains its hold on the
slide. Objects mounted in glycerine keep
best ; but in many instances the structure is
entirely destroyed by it. This difficulty may
be often overcome, by adding very diluted
glycerine to the object at first, replacing it
gradually by stronger as the water evapo-
rates, until at last the object becomes really
mounted in pure glycerine.

Many moist objects may also be mounted
in balsam or dammara-solution, by first
macerating them in weak alcohol, then in
stronger, next in oil of cloves, and finally in
balsam.

Even objects mounted in balsam are not
safe ; for when the balsam becomes really
dry, it separates from the slide, and air runs
in. Balsam thinned with turpentine, and
gradually added, perhaps with the aid of
gentle heat, will, however, restore the ori-
ginal condition. And the cement around
older objects should be varnished occa-
sionally with dilute balsam or dammara-
benzole solution.

The deeper the cell, the less the chance
of the object being spoiled.

As soon as objects are mounted, the slides
should be labelled with a square or circular
piece of paper pasted upon them, the name
and other particulars being expressed in
writing. The name &c. may also be
written upon slides with a diamond : but
the paper labels should always be used;
otherwise much time will be lost in search-
ing for and distinguishing particular objects
in the cabinet.

For preserving dried plants from mould
and insects, the old method was to brush
them with a solution of a grain or two of
corrosive sublimate dissolved in an ounce
of spirit. The " Kew mixture" for the
same purpose, is made with corrosive sub-
limate and crystallized carbolic acid, of each
\ oz., methylated spirit a pint. Perhaps

PRIMITIA.

[ 637 ] PRIMORDIAL UTRICLE.

|- of this strength is sufficient for general
use. The same may be applied to insects
in the cabinet, by means of a hair-pencil.
Berkeley points oat that carbolic acid alters
the colour of some fungi.

BIBL. Treatise upon the Microscope
(IxmoD.) ; Corti, Sieb. und Kott. Zeit. iii.
134; Goadby, Amer. J. xiii. 15; Davies-
Matthews, Mounting ; Mohl, Bot. Zeit. xv.
249 ; Beale, How ; Carpenter, Microscope ;
Frey, Mikr. ; Strieker, Hist. ; Heys and
Hepworth, Tr. Mic. Soc. 1865 ; Lawrence,
Qu. Mic. Jn. 1859, 257 ; Walmsley, Mn.
Mic. Jn. i. 380; Bastian, ibid. i. 94;
Mouchet, ibid. iii. 75 ; Bachrnann, Anf. mik.
Prdparat.

PRIMI'TIA, J. & H.— A small fossil
Ostracode with suboblong valves, impressed
with a variable furrow or pit in the medio-
dorsal region. Forty species in the Silurian
rocks of Britain, Europe, and America.

BIBL. Jones & Hall, Ann. N. H. 3. xvi.
415.

PRIMORDIAL UTRICLE.— This term
indicates a peculiar portion of the contents
of the cellulose sac constituting a vegetable
cell. »As the formations comprehended
under this name are of great importance in
the development of vegetable cells, a little
detail must be entered into in explaining
the subject.

If a cell of the pulp of any succulent
fruit, a cell of yeast, or cells in sections
taken from the delicate nascent tissues of
any growing part of plants, are placed in
water, the entire contents will soon be seen
to retract from the cellulose wall, leaving a
clear space, filled with transparent liquid,
between the latter and a sharply defined
line bounding the contracted or coagulated
contents (PI. 47. figs. 1, 2, 10-12). The
addition of tincture of iodine makes the
conditions still more clear. If the parent
cells of pollen-grains or spores are treated
thus, just before the development of the
cellulose wall of the special parent cells (see
POLLEN), the four portions of the contents
of the parent cell contract and separate, and
each portion, containing its own granular
structures and nucleus, appears bounded by
a well-defined line (fig. 607). This well-
defined line presents in this condition the
appearance of a delicate membrane or pel-
licle enclosing the entire contents. The
action of acids, or spirit, and iodine, reveals
the existence of a similar set of conditions
in all actively vegetating cells ; and in most
cases a more or less thick viscous layer of

the protoplasm is found lining the cellulose
wall before the application 01 the reagents.
Since the line indicating the boundary of
the contents cannot be distinctly seen until
the contents have retracted from the cellu-
lose wall, and since the protoplasm is always
coagulated by the action of the reagents, it

Fig. 607.

Fig. 608.

CM.

p

Fig. 607. Parent cells of pollen-grains just after the
separation of the contents into four portions, treated
with iodine. CM, the parent cell. P, the protoplasmic
portions, each with a nucleus and a well-defined outline
at the surface of the primordial utricle. Magnified 250
diameters.

Fig. 608. Cells of Protococcus multiplying. The green
granular contents are bounded by the definite outline
of the primordial utricle : the primary and secondary
cellulose parent-cell membranes are represented as
separated from each other. Magnified 400 diameters.

is a subject of discussion whether the film
forming the well-defined line on the surface
of the contracted contents is a true struc-
ture, or only a pellicle produced by the
coagulation of the surface of the protoplasm,
just as a "skin" forms over size, or other
similar substances when they dry up in the
air. Very young cells often appear filled
with a dense protoplasm (young antheridial
cells of Cryptogamia, embryo-sacs of many
flowering plants, cells about to produce
zoospores in the Confervoids, &c.), which
may produce numerous new cells by merely
breaking up into separate portions; and
thus the function of the primordial utricle
is shared by tKe entire mass of contents.
Young cells of nascent tissues, presenting
this condition at first, acquire the primor-
dial utricle afterwards, simply by the dense
contents becoming excavated as the cell-
wall expands, and following this in its
growth, so that the originally dense homo-
geneous mass becomes a hollow sphere
with the centre occupied by watery cell-
sap; in other cases the originally homo-
geneous protoplasm becomes excavated by
numerous water-vesicles, and thus honey-
combed, until it forms a mere reticulation
of protoplasmic threads upon the wall or
stretched across the cavity. The proto-
plasmic layer lying upon the wall of the

PRITCHARDIA.

[ 638 ]

PROSTHEMIUM.

cell presents a complex arrangement in
some cases : Braun correctly distinguishes
three layers in Hydrodictyon ; there are
three in Chara, where the intermediate one
contains the chlorophyll-granules, and the
innermost forms the circulating mass; a
distinct layer is left after the discharge of
the zooapores in Cladophora, &c. Thus, as
explained under the head of CELL-forina-
tion, the primordial utricle or formative
protoplasmic layer is the active agent in
cell-division, and the layer forming the
surface of the isolated portions of contents
of parent cells produces the new cell-wall
in all cases of free-cell formation, whether
taking place in parent cells, or, as in the
case of the zoospores of Algae, after escape
from the latter. Strassburger describes
the primordial utricle as being radiately
striated, especially when treated with osmic
acid.

In many of the Algae, some of the indivi-
dual cells regularly exist for a certain period
as masses of protoplasm devoid of a cellulose
coat, as, for example, the spores of Fucus \
and its allies, and the active zoospores of
Conferyoids; and these bodies, although
presenting a well-defined outline, do not
appear to have a properly developed mem-
brane on the surface, which merely appears
to be denser than the semifluid central por-
tion. These bodies withdraw themselves
evidently from the definition of a vegetable
cell as ordinarily given; nevertheless they
constitute all the essential living part of a
vegetable cell, and indicate most clearly
the undoubted fact that the cellulose walls,
that is to say all the really solid and per-
manent portions of vegetable structure, are
mere skeleton or shell for the protoplasmic
or nitrogenous structures.

BIBL. Mohl, Bot.Zeit.\\. 273; Vcrmischte
Schrift. 362; Henfrey, Ann. N. H. xviii.
364; Nageli, Zeitschr. wiss. Sot. 1844 &
1846; Braun, Verj'iing., Hay Soc. 1853,
121 ; Cohn, Nova Acta, xxii. 605 ; Prings-
heim, Bild. d. Pftanzenzelle, 1854 ; Hartig,
Bot. Zeit. xiii. 393 ; Criiger, ibid. 601 ; Sachs,
Bot. 43 ; Henfrey-Masters, Bot. 495.

PRITCHAR'DIA, Raben— A genus of
Diatomaceae, comprising certain species of
Nitzschia and Synedra. (Rabenht. Alg. i.
162.)

PROBOSCEL'LA, Kt. — A genus of
Holotrichous Infusoria. Elongate-clavate,
compressed, with aii apical hook; mouth
ventral ; an undulating membrane between
the front and mouth; with one or more

caudal setae. P. vermina ; marine length
1-250".

PROEMBRYO.— The term applied to
the structure first produced from the ger-
minal vesicle of Flowering Plants, after im-
pregnation, consisting of the suspensor and
the embryonal cell at its extremity. The
proembryos of the Gymnosperms are espe-
cially remarkable (see OVULE). The same
term is often incorrectly applied to the pno-
THALLIUM, the cellular structure first pro-
duced in the germination of the spores of
the higher Flowerless Plants.

PROROCEN'TRUM, Ehr.— A genus of
Cilio-flagellate Infusoria.

Char. No eye-spot ; carapace smooth,
terminating in a point in front; flagellum
single.

P. micans (PI. 31. figs. 70 & 71), ovate,
greatly compressed ; length 1-430".

BIBL. Ehr. Inf. 44 ; Clap, et Lach. Infus.
411 ; Kent, Inf. 461.

PROR'ODON, Ehr.— A genus of Holo-
trichous Infusoria, family Trachelina.

Char. Body covered with vibratile cilia,
truncate in front ; mouth with a cylinder of
teeth ; freshwater. Species numerous.

P. teres (PI. 31. fig. 72). Body ovate,
terete, white. Length 1-140".

BIBL. Ehr. Inf. 315; Clap, et Lach.
Infus. 318 ; Kent, Inf. 491.

PROSEN'CHYMA. See TISSUES, Ve-
getable.

PROSTHE'MIUM, Kunze. — A genus
of Melanconiei (Coniomycetous Fungi),
growing upon the branches of trees, form-
ing circular depressed spots ; the perithecia

Fig, 609.

Prostheminm betnlinum.

Spores and paraphyses seen in a vertical section of frut.
Magnified 200 diams.

enclose erect articulated filaments bearing
radiating tufts of two or three septate spores
(fig. 609). P. hetulinum occurs upon the
bark of the branches of the birch tree. The
species are mere forms of Sphceriacei.

PROTAMCEBA.

[ 639 ]

PROTOCOCCUS.

BIBL. Berkeley, Brit. Flor. ii. pt. 2. p.
297.

PROTAMCE'BA, Haeckel.— A genus of
Protista.

Char. A simple shapeless protoplasm-
bodv without vacuoles, with simple pseudo-
podia, not ramifying nor anastomosing ; re-
production by fission.

Species. Protamceba primitiva. Proto-
plasm-body of 0-03-0*05 millim. diameter,
continually varying in form, with one or
several (3 to 6) peripheral pseudopodia.
Processes short, rounded, obtuse, finger-
shaped, at most as long as the diameter of
the central body. Freshwater, near Jena.
(Haeckel, Gen. Morphol. 1866, i. 133.)

PROTEA'CE^E. -A family of Dicotyle-
donous plants, mostly from New Holland
or the Cape, shrubs or small trees (Banksia,
Grevillea, Hakea, &c.), of remarkably rigid,
evergreen habit. The coriaceous leaves are
well suited for the study of the epidermal
structures; and the stomata have interesting
peculiarities (see STOMATA). The epider-
mis is often scurfy with scattered hairs,
some of which are of curious forms (PI. 28.
fig. 29).

PROTEONTNA, Williamson.— A simple
Arenaceous Foraminifer ; a feeble Lituola of
the Haplophragmium group.

BIBL. Williamson, For am. 1 j Carpenter,
For. 309.

PROTEUS.— An old name applied to
certain Infusoria, as Amoeba &c. Also a
genus of Amphibia with large blood-cor-
puscles.

PROTHAL'LUS on PROTHALLIUM.
— The structure resulting from the germi-
nation of the spores of the Cryptogainia, in
which the female, and sometimes the male
organs are formed. See MARSILEACE.E,
LYCOPODIACEJE, EQUISETACEJE, and FKKNS.

PROTISTA, Haeckel.— A kingdom of
organic nature supposed to be intermediate
between the animal and vegetable king-
doms, and comprising the so-called lowest
forms of life. It is divided into the follow-
ing groups : —

/ 1. G-ymnomonera (Protogenes, Pro-
tamceba, &c.).

I. Monera. -< 2. Lepomonera (Protomonas, Vavfi-
pyrella,Protomyxa,Myxastrum,
( &c.).

/I. Nudiflagellata (Euglena, Spon-
TT •KMo/roii fa J dylomorum, &c.).

II. Flagellate... 2 Cili*flagellata (/^YKnfrm, Ce-

(. ratium, &c.).

III. Labyrinthulea (Ldbyrinthula).

IV. Diatomea (Bacillaria).

VIII. Protoplasta (Amoeboida).*

{1. Chrysococcacea (Glce-
ocapsa, Merismopce-
dia, &c.).
2. Oscillarinea (Nostocha-
cea,Rivulariacea, &c.).

1. Phycomycetes (Saprolegniece , Mu-

corinece, &c.).

2. Hypodermiee ( Uredince, Ustilagince,

VI. Fungi, -j g Basid'iomycetes (Hymenomycetes ,

Gastromycetes, &c.).
4. Ascomycetes (Protomycetes, Disco-
\ mycetes, &c.)«
VII. Myxomycetes (Mycetozoa).

/I. Gymnamcebae

(Autamaba, &c.).
2. Lepamcebae (Ar-
cella, Diffiugia,
&c.).

3 G-regarirse
^ (Grregarina) .
IX. Noctilucee Noctiluca.

(I. Acyttaria (Monothalamia and

Polythalamia).
X. Eliizopoda. -| 2. Heliozoa (Actinosphcerium').

3. Eadiolaria (Monocytharia and
( Polycytharia).

BIBL. Haeckel, Gen. Morph. ; Mon. Mo-
neren, Jenai. Zeit. 6. iv. 1 ; Biol. Studien,
1 ; Wright and Kirby, Qu. Mic. Jn. 1869 &
1871 ; Kent, Inf. 44.

PROTOCOC'CUS, Ag.— A genus of Vol-
vocineae (Confervoid Algae), at present very
imperfectly known, since without a toler-
ably complete history of the development
of the forms it is impossible to distinguish
the true species of Protococcus from the
young states of the more complicated Pal-
mellaceaB, and even from the germinating
gonidia of the Lichens. As we have limited
it, Protococcus includes those unicellular
Algae which in the aquatic state consist of
single zoospore-like bodies, with a more or
less evident gelatinous cellulose envelope
through which the two cilia protrude.
They move actively, and are multiplied by
division during the active state. Finally
they settle down into a resting-stage j and
they may then increase by vegetation so as
to form granular patches. Mostly, however,
those which settle down turn red and ac-
quire a thick coat, passing through a stage
of rest before they germinate again, appa-
rently requiring to be dried up first. When
they germinate, they frequently produce
many generations of still forms before the
active ciliated forms reappear, especially
when placed on damp surfaces, and not in
water. When placed in favourable circum-
stances, the resting-f orms (even after several
years) recommence the course of vegeta-
tion, reacquiring the green colour by de-
grees in the course of several generations of
vegetative cells. The contents of the red

PROTOCOCCUS.

[ 640 ]

PROIOMYCES.

form appear to consist partly of oil-glo-
bules ; in the green form the protoplasmic
substance is coloured by chlorophyll; and at
a certain stage contains starch.

We have traced P. viridis through all
these stages, as represented in PI. 7. fig.
2 a-y : a most elaborate monograph of P.
pluvialis by Cohn goes to establish the same
conclusion, that the genus Hcematococcus is
founded on states of Protococcus. The P.
viridis of our figures is undoubtedly Clila-
midomonas, synonymous with Diselmis, Du-
jardin. This form appears at first sight
nearly allied to Euglena-, but there are
striking differences in the appearance and
movements of the active forms, and the
vegetative forms are somewhat different.
It may be remarked, however, that the
zoospores of Protococcus viridis, allowed to
dry upon a slide, often turn red and look
just like small Astasice (PI. 7. fig. 2#).

We have remarked under PALMELLA,
that the Polar red snow appears to be a
Palmella (PI. 7. fig. 3d), although this
species has been called Protococcus and
Hcematococcus nivalis ; and it appears to us
that Shuttleworth and others have con-
founded this with Protococcus pluvialis.
Hassall's species of Hcematococcus, nos. 8 to
19, with the exception of H. vulyaris (Chlo-
rococcum) (PI. 7. fig. 1), are probably con-
generic with our P. viridis.

Our P. viridis makes its appearance com-
monly on damp earth, sand, &c., forming a
greenish coat of no perceptible thickness;
and the zoospores (Chlamidomonas) occur
constantly in standing pools in spring and
autumn, tinging the surface of the water
bright green, and, as they settle to rest,
forming a kind of green scum at the mar-
gins, constituting the green matter of
Priestley. Cells of resting-fonn 1-2400"
in diameter. P. pluvialis colours water red
in like manner ; it occurs on mountains,
especially in melted snow-water. Cells of
reating-form 1-1250 to 1-625" in diameter.
Similar colorations, however, are produced
by various other organisms (see WATER}.

It may be observed that when the active
forms of P. viridis and P. pluvialis divide
without coming to rest, they produce forms
which are undistinguishable from many of
Ehrenberg's species of Polygastrica. When
they acquire a loose cellulose coat before
losing their cilia, they represent Gyges ; at
other times they resemble Chlorogonium,
Uvella, Polytoma, Monas, Bodo, &c.

BIBL. Harvey, Br. Alg. 1. 180 ; Hassall,

Fr. Ala. 321 ; Meneghini, Tr. Turin Ac. 2.
v. 1 ; Cohn, Nova Acta, xxii. 605, Ray Soc.
1853, 514; Von Flotow, Nova Acta, xx.
414; Braun, Verjunyuny, Ray Soc. 1853,
206 ; Nageli, Einzelliye Algen ; Kiitzing, Sp.
Alg. 196 ; Tab. Phyc. i. ; Rabenh. Alg. iii.
56 ; Cooke, Fr. ivat. Algce, 1882. See also
RED SNOW.

PROTODER'MA, Ktz.— A genus of Ul-
vacese (Confervoid Algae).

Char. Cells forming a thin ineinbrano-
crustaceous expansion ; they are roundish
angular. P. viride (PL 3. fig. 18), fresh-
water; on stones; cells 1-300".

BIBL. Ktz. Phyc. Gen. 295 ; Rabenht.
Alg. iii. 307.

PROTOG'ENES, Haeckel.— A genus of
Protista.

Char. A simple shameless protoplasm body
without vacuoles, which protrudes ramify-
ing and anastomosing processes, and repro-
duces itself by fission. Protogenes primor-
dialis. Body sometimes globular,from 1-200-
1-25" diameter, sometimes extended and
flattened out, with irregular outline, to 1-10"
diameter; pseudopodia exceedingly nume-
rous, over a thousand, very fine, with very
numerous ramifications and anastomoses.
Mediterranean.

BIBL. Haeckel, Zeitschr. iviss. Zool. xv.
1865, 360.

PROTOHY'DRA, Greef.— A genus of
Zoophytes. Like Hydra', but simpler in
structure, as it has no tentacles. Reproduc-
tion by transverse fission ; nematophores and
pigment-cells present.

BIBL. Greef, Sieb. u. Kdll. Zeit. i. 1870;
Qu. Mic. Jn. 1870, 297.

PROTOM'ONAS, Haeckel.— A genus of
Protista.

Char. A simple protoplast, without
vacuoles, simple or ramifying pseudopodia.
Reproduction by zoospores, which combine
into meshes or plasmodia.

Protomonas amyli. In decaying Nitella.
(Haeckel, Gen. Morph. vol. ii. 23, Qu. Mic.
Jn. 1869.)

PROTOM'YCES, linger.— A genus of
Fungi, the affinities of which are very
doubtful ; placed in Ascomycetes by Sachs,
but apparently forming a degraded branch
of Phycomycetes. They grow in the inter-
cellular passages of leaves and leaf-stalks.
According to De Bary, these Fungi consist
of ramified filaments creeping between the
cells of soft tissues, and swelling up at inter-
vals (apparently where they meet an inter-
cellular space large enough), to form globular

PROTOMYXA.

[ 641 ]

PROTOZOA.

spores : a filament with several spores in
course of division appears like a varicose
tube ; it is septate, however ; and when the
globular spores are mature, they have a
double coat; in P. macrosponts the diameter
of the ripe spore is about 1-5000". When
advanced in age, the mycelium appears to be
whollv converted into spores, which become
free. The existence of these Fungi is ren-
dered more or less evident externally by
w.irtv projections of the epidermis, finally
bursting. Unger describes four species — P.
macrosponis occurring on JEyopodium and
Angelica, P. endoyenus (Galii) occurring on
Gcdiuin mollugo, P. microsporus on Ranun-
culus repens, and P. Paridis on Paris qua-
dnfolia. De Bary found a species on Me-
ni/anthes, with oval spores 1-800" long- and
1-1300" broad. A species (P. cancomitaw)
has lately been found on exotic Orchids.

BIBL. "linger, Exanthem. d. Pftanz, 341 ;
Da Bary, Brandpilze, 15, pis. 1 & 2, and
Beitmge,\. 1864; Leveille, Ann. So. Nat. 3.
viii. 374; Tulasne, ibid. vii. 112; Fries,
Sum. Veq. 517.

PROTOMYX'A, Haeckel.— A genus of
Protista.

Char. A simple shapeless mass of proto-
plasm, with vacuoles, which protrudes rami-
fying and anastomosing pseudopodia. Re-
production by zoospores, forming plas-
modia.

Protomyxa aurantiaca, orange-red ; resting
condition globular, with a thick structure-
less covering. Zoospores pear-shaped, with
a strong flagellum at the pointed end, at first
moving like the zoospores of the Myxo-
mycetes, afterwards creeping like an Amoeba.
On empty shells of Spinda ; Canary Islands.
(Haeckel, Gen. Morph. ; Bronn, Klass. fyc.)

PROTOMYXOMY'CES, Cunn. — A
genus of Myxomycetes. P. coprinarius, in
the intestines of man, cows &c. ; amoeboid
bodies not uniting. (Cunningham, Qu.
Mic. Jn. 1881 ; Kent, Inf. 472.)

PROTOPLASM.— The name applied by
Mohl to the colourless or yellowish, homo-
geneous or granular viscid substance, of
nitrogenous constitution, which constitutes
the formative substance in the contents of
vegetable cells, in the condition of gelatinous
strata, reticulated threads, and nuclear aggre-
gations &c. It is the same substance as that
termed by Dujardin in animals SARCODE.

Protoplasm is the simplest form which
organized matter can assume, and which,
without any other material peculiarities
except a certain softness, transparency, and

jelly-like condition, is capable of contracting,
expanding, and assimilating. It is common
to the animal and vegetable kingdoms.
See CELL, SARCODE, and PRIMORDIAL

UTRICLE.

PROTOSPON'GIA, Kt— A genus of
Choano-flagellate Infusoria. Ovate, imbed-
ded in a gelatinous matrix ; flagellum single.
P. Haeckelii ; length 1-3000' ; freshwater.
(Kent, Inf. 363.)

PROTOZO'A.— A Subkingdom of the
Animal Kingdom, characterized by the
absence of distinct organs, the form and
simple organization being reduced to those
of a cell (Siebold). If the above definition
be adopted, it must be remembered that the
cell may be represented by the cell-contents
only ; and these we believe to constitute the
essential part of a cell (see Edition 1856),
which is now generally admitted.

The Protozoa form the lowest group of
the Animal Kingdom. They are mostly
minute, and aquatic, consisting of a mass of
gelatinous protoplasm or sarcode. This is
usually granular, often containing minute
globules of fat, sometimes minute crystalline
particles. Sometimes one or more nuclei
are present, often they are absent. The body
is naked in some, in others it is enveloped
in a carapace or shell, which may be simply
membranous, calcareous, as in the Forami-
nifera, or siliceous, as in the Polycystina and
AcanthometrcB. Movement is effected by
pseudopodia, which are short and stout, or
long and slender, processes of the protoplasm,
sometimes branching and anastomosing to
form meshes or plasmodia ; by cilia ; or by
flagelliforni filaments. There is no proper
gastric cavity. The food-particles are in the
lowest forms entangled and brought to the
body by the pseudopodia, as in Amceba and
Actinophrys &c., or ingested from all parts
of the surface ; while in many Infusoria there
is a distinct mouth and anus. Contractile
vesicles supposed to represent a circulatory
apparatus are sometimes, but not always
present. Reproduction is produced by fission,
by conjugation, or by the breaking-up of the
nucleus.

The Protozoa approach closely the lower
and simpler forms of the Vegetable Kingdom ;
and very different views are held as to the
characters by which they may be distin-
guished, and the organisms which belong to
the two kingdoms.

An older character was, that animals
subsist upon ingested organized matter,
while plants prepare their food from un-

2x

PSAMMOSP1LKKA.

PSILOTE^E.

organized materials, as carbonic acid and
ammonia. The other, that animals absorb
oxygen and evolve carbonic acid, while
plants evolve oxygen, cannot be applied
generally in the case of these microscopic
organisms. But certain Protozoa have no
mouth, and cannot admit food-particles like
Amoeba, nor can organic matters be eudos-
mosed by them. Movement has in late
years been shown to be a property of proto-
plasm, limited where a cell-wall is present,
yet it may be said to be universal. Stein
and Kent consider the presence of a contrac-
tile vesicle to form a distinctive- character ;
but its existence in Volvox, we think must
invalidate this view.

The chemical property of the protoplasm,
that of animals swelling and dissolving in
solution of potash or ammonia, while that
of plants is apparently unaffected, has also
been called in aid ; and this really appears
to be the best individual test. Little atten-
tion has been paid to this part of the question,
so that the older views must remain, until
further experiments have been made. See
ANIMAL KINGDOM, and the heads of the
Classes.

BIBL. Siebold, Vergl. An. i. ; Koch, Icon.
Hut. 1865 ; Gabriel, Gegenlaurs Morph.
Jahrb. 1875 ; Mereschowski, Russl. Arch,
mik. An. 1878, xvi. ; Butschli, fironn's Xlass.
#c.; Kent,/*/. 1880,31.

PSAMMOSPILE'RA, Schultze. — An
Arenaceous Foraminifer, round, free or
attached, made of coarse sand-grains and
fine cement ; common in deep seas. (Brady,
Qu. Mic. Jn., new ser. xix. 8.)

PSECA'DIUM, Reuss.— A globose or
Glanduline Marginulina. Fossil.

BIBL. Reuss, Sits. Ak. Wien, xliv. 368.

PSEUDOCALA'NUS, Boeck.— A genus
of marine Copepoda. 2 sp. (Brady, Copep.,
Ray Soc. i. 44.)

PSEUDOCH'LAMYS, Clap, et Lach.—
A genus of Arcellina (Rhizopoda). P. ni-
tella ; carapace brown, pseuaopodia broad
and short ; in ponds. (Claparede et Lachm.
Inf. 443.)

PSEUDOC YC'LOPS,Brady.— A genus of
rnarineCopepoda. 2sp. (Brady, Co/we, i. 81.)

PSEUBOCYTH'ERE, G. O. Sars.— One
of the Cytherida-, valves very thin, obliquely
quadrangular ; five joints in upper, seven in
lower antennae, which are long and have
long setaB ; no eyes. 1 British species.

BIBL. Brady, Linn. Tr. xxvi. 453.

PSEUDODIFFLUGIA, Schlurn, — A
genus of Arcellina.

Char. Shell membranous, ovoid or ovo-
globular, smooth or striped spirally, with a
wide round opening whence issue pseudo-
podia. (Pritchard, Infusoria, p. 557.)

PSEUDOGON1DIA — A term applied to
bodies appearing in the interior of cells of
Algae, which are obscure in their nature,
being either metamorphosed and isolated
masses of protoplasm, or parasitic bodies
resembling monads. They are apparently
connected with the objects called CHYTIU-
DIUM and PYTHIUM. (Cienkowski, Prinys-
heim's Jahrb. Sot. i. 371.)

PSEUDOG'RAPHIS, Nyl.— A genus of
Microlichens parasitic on Lecanorae.

Char. Spores colourless or becoming
brown, 4-6-locular, sometimes becoming
submuriform ; slightly blue with iodine.

BIBL. Lindsay, Qu. Mic. Jn. 1869, 352.

PSEUDOPO'DIA are the processes of

Ctoplasm which are protruded from the
ies of the RHIZOPODA, serving for loco-
motion and the prehension of food.

PSEUDOS'PORA, Cien.— A genus of
Flagellate Infusoria. Body naked, swimming
or creeping; flagella two, equal ; no mouth.
P. volvoets, on and in Volvox: length
1-1250". (Kent, Inf. 304.)

PSEUDOSPORES. — The apparent
spores of Uredinei and Tremellini, which
germinate and produce the real reproductive
spores, which are then called spuriola.

PSICHOHOR'MIU M, Ktz.— This genus
consists of species of Conferva, whose iila-
ments are more or less incrusted with oxide
of iron or carbonate of lime.

BIBL. Rabenh. Fl. Evr. Alg. iii. 324.

PSILO'NIA, Fr.— A genus of Sepedoniei
(Hyphomycetous Fungi), consisting of little
compact tufts of twisted filaments, at
first covering the fusiform, globose, or oval
spores, which arise from the wart-like pro-
tuberances on the central filaments, and
soon become free. They are found on dead
wrood or on reeds. P. nivea, which is com-
mon on the bark of beech-trees, is the
product of an insect, AdeJgesfagi.

BIBL. Berk. Br. Fl. ii.'pt. 2. 353 ; Ann.
N. H. 2. viii. 179 ; Fries, Sum. Veg. 495.

PSILOTE^E.— A family of Lycopodia-
ceous plants, distinguished by their many-
celled sporanges, varying much in habit and
external appearance.

Synopsis of Genera.

Psilotum. Sporanges sessile, three-celled,
busting imperfectly into three valves by a
vertical crack, filled with mealy spores.

PSILOTE.E.

[ 043

PTERIDEJ3.

Tmesipteria. Sporanges sessile, three-
celled, bursting imperfectly into two valves
by a vertical crack, tilled with mealy spores.
" Isoetfs. Sporanges imbedded in the bases
of the leaves, and adnate at the back, not
valvate, with several transverse septa ; con-
taining two kinds of spores (in distinct spo-
rangia).

Fig. 610.

Psilotum triquetrum.
Nat. size.

Fig. 611.

Fragment of a branch of Psilotum triquetrum.
Miigniflcd 10 diameters.

PSILOT'RICIIA, St.— A genus of lly-
potrichous Infusoria. Body oblong, tlatu-ncd,
with 2 rows of long ventral, and a peripheral
row of setae, but no styles. P. dCMmmoftf,
freshwater. (Kent, Inf. 672.)

PSILOTUM, Swartz. (Lycopodium » n-
dum, L.). — An exotic genus of Pailotese (Ly-
copodiacere), remarkable for their trilocular
capsules and minute leaves (tig. 611).

PSORO'MA, Nyl.— A genus of Lichena-
ceous Lichens, with large distinct gonidia.

BIBL. Leighton, Lich. Flora, 14',).

PSOROP'TES, Gervais.— A genus of
Arachnida, of the order Acarina, and family
Acarea.

Char. Body soft, depressed, with rigid
hairs beneath, and on the legs.

Parasitic upon the horse and sheep, and
the ox.

P. equi (PI. 6. fig. 18), itch-insect of the
horse. Found upon the scaly crusts formed
upon the body. Mandibles elongate, didac-
tyle, each terminated by two teeth ; palpi
three-jointed, and adherent to the labium ;
ventral surface covered with parallel undu-
lating rugae; at the end of the body are
two fleshy lobes, terminated by a tuft of setse.

BIBL. Heriug, Nov. Act. xviii. 585; Ger-
vais, Walckenaer^s Apttres, iii. 266 ; Uujar-
diu, Micr. 147; Murray, EC. Ent. 307;
Me'gnin, Paras. 189.

PSOROSPERMLE.— These bodies were
discovered by Mu'ller, and appear to repre-
sent the pseudo-navicula3 of the Gregarince
of fishes.

They are microscopic, oval, depressed, or
discoidal corpuscles, with or without a tail,
exhibiting no movements, and consisting of
a tolerablv firm outer coat, containing one
or two oolong contiguous vesicles at that
end of the body opposite the tail. They are
about 1-2500 to 1-2000" in length, and are
contained in immense numbers in minute
cysts, in almost every part of the body of
fishes, as upon the gills, in the muscles, and
between the coats of the eye, in the swim-
ming-bladder, &c. Sometimes they are
imbedded in a ramified sarcodic mass.

Diameter of the cysts on the pike 1-50 to
1-25" ; of the corpuscles, length 1-2000",
breadth 1-3500". See PEBRINB.

BIBL. Miiller, Archtv, 1841. 477, 1842.
193; Creplin, ibid. 1842. 61; Dujardin,
Helminthes, 643; Leydig, Mutt. Archiv,
1851, 221, Mic. Jn. 1853, i. 206; Robin,
Vtgtt. Parasit. 2. 291.

PTERID'E^.— A family of Polypodia-
ceous Ferns. Genera :

2x2

PTERIDE^E.

[ 644 ]

PTEROPTUS.

Adiantvm. Sori marginal, linear or glo-
bose, numerous and distinct, or confluent.
Indusium shaped liked the sorus, formed of
the reflexed margin of the fronds, with the
capsules beneath.

Ochropteris. Sori marginal, transversely
oblong, at the apices of the lobes of the
segments. Indusium the same shape as the
frond, formed of its reflexed margin.

Lonchitis. Sori marginal, in the sinuses of
the frond, reniform or elongated. Jndusium
shaped like the sorus, membranous, formed
of the frond.

Hypolepis. Sori marginal, in the sinuses
of the frond, small, subglobose, uniform.
Indusium formed of the reflexed margin,
membranous.

Cheilanthes. Sori terminal or nearly so on
the veins, at first small, subglobose, after-
wards confluent. Indusium formed from
the changed reflexed margin, roundish, or
confluent, not quite continuous.

Cassebeera. Sori terminal on the veins,
globose or oblong, not reaching beyond the
branches of a single vein. Indusium in-
serted within the margin, and separate from
it, shaped like the sorus.

Onychium. Sori on a continuous linear
receptacle, connecting the apices of several
veins. Indusium parallel with the margin
of the segments, linear, opposite, pressed
over the sori, the edge nearly or quite
reaching the midrib.

Llavea. Sori linear, occupying the
whole length of the changed pod-like seg-
ments of the upper part of the frond. In-
dusium the same shape, rolled over and
concealing them.

Cryptogramma. Sterile and fertile fronds
usually different, from the same root ; sori
terminal on the veins, at first subglobo.«e, then
confluent, the continuous indusium formed
of the changed inrolled margin of the frond.

Pellcea. Sori intramarginal, terminal on
the veins, at first dot-like or decurrent on
the veins, then running into a line. Indu-
sium formed of the more or less changed
edge of the frond, continuous, sometimes
very narrow.

Pteris. Sori marginal, linear, continuous,
occupying a slender filiform receptacle in
the axis of the indusium. Indusium the
shape of the sorus, usually membranous, at
first covering it, then spreading.

Ceratopteris. Sori placed on two or three
veins which run longitudinally down the
frond, and which are nearly parallel with
both the edge and the midrib. Indu-

sium formed of the reflexed margin of the
frond, those of the two sides meeting at the
midrib.

Lomaria. Sori linear, continuous, lon-
gitudinal, and occupying the space between
the midrib and the edge. Indusium mem-
branous, formed of the revolute margin of
the frond.

PTERIS, Linn.— A genus of Pteridese
(Polypodiaceous Ferns), represented by one
indigenous species, Pteris aqidlina, the com-
mon Brake Fern ; numerous tropical species.
(Hooker, Syn. 153.)

Fig. 612.

Pteris.

A pinnule with marginal indusiate sori.
Magnified 10 diameters.

PTEROCOM'MA, Buckt— A genus of
Aphidse. P. pilosa, on willow-twigs. (Buck-
ton, Aphides, Ray Soc. ii. 142.)

PTERODI'NA, Ehr.— A genus of Rota-
toria, of the family Brachionaea.

Char. Eyes two, frontal; foot simply
styliform. At the end of the tail-like foot
is a suctorial disk; jaws with the teeth
either arranged in a row, or two teeth only
in each.

Three species; two freshwater, one
marine.

P. patina (PI. 44. fig. 20). Testula mem-
branous, orbicular, crystalline, roughish
near the broad margin ; a depression pre-
sent between the rotatory lobes. Fresh-
water; length 1-120".

BIBL. Ehrenberg, Infus. 516 ; Pritchard,
Inf. 711.

PTEROP'TUS, Dufour. — A genus of
Acarina (Arachnida), family Gamasea.

Char. Body depressed ; last joint of palpi
longest; legs stout, with short joints.

P. vespertilionis (PI. 6. fig. 39). Found

PTERYGIUM.

[ 645 ]

PUCCINIA.

upon bats. Several species have been de-
scribed.

BIBL. Gervais, Walckenaer's Apteres, iii.
227 ; Duf our, Ann. Sc. N. xvi. 98, xxv. 9 ;
Koch, Deutschl. Crustac.; Murray, EC. Ent.
175.

PTERYGIUM, Nyl.— A genus of Colle-
maceous Lichens. 2 species, on calcareous
rocks. (Leighton, Lichen Fl. 12.)

PTERYGO'NIUM, Sw. — A genus of
Mosses. See NECKEBA.

PTILID'IUM, Nees.— A genus of Jun-
germanniese (Hepaticse), containing one ele-
gant British species, P. ciliare, frequent on
heaths and rocks in subalpine districts, but
rarely found in fruit.

BIBL. Hooker, Br. Fl ii. 126; Br. Jung.
pi. 65 ; Ekart, Jung. pi. 5. fig. 36.

PTILO'TA, Ag. — A genus of Ceramiacese
(Florideous Algae), with flat feathery fronds
a few inches high; of a deep red colour,
growing on Laminariae or Fuci, or on rocks
between tide-marks. The fructification
consists of: — 1. clustered roundish favellce
containing spores, terminating the ultimate
pinnules, and surrounded by an involucre
of subulate ramuli, or naked ; 2. tetrahedral
tetraspores on short pedicels fringing the
pinnules. Antheridia have not been ob-
served. P. plumosa (PI. 4. fig. 16).

BIBL. Harvey, Mar. Alg. 159, pi. 22 A ;
Phyc. Br. pi. 70 ; Greville, Alg. Br. pi. 16 ;
Nageli, Algensystem, pi. 6. figs. 38-42.

PTYCHOG'RAPHA, Nyl.— A genus of
Graphidei (Lichenaceous Lichens). 1 sp.,
on decorticated mountain-ash. (Leighton,
Lich. Fl. 392.)

PTYCHOS'TOMUM, St.— A genus of
Holotrichous Infusoria. Free, ovate, un-
symmetrical, mouth ventral. 2 species, in
the intestines of Annulata (Tubifex}, and
Mollusca (Paludina). (Kent, Inf. 541.)

PTYGU'RA, Ehr.— A genus of Rotatoria,
of the family Ichthydina.

Char, Eyes none; no hairs upon the
body ; tail-like foot cylindrical, simply trun-
cate.

Teeth three in each jaw ; anus situated
at the end of the tail-like foot.

P. melicerta (PL 44. fig. 2 L). Body terete-
clavate, turgid in front, hyaline; mouth
with two little hook- like horns ; cervical
process single and smooth. Freshwater ;
length 1-144". Ehrenberg questions whe-
ther this is not a young form of another
genus.

BIBL. Ehrenberg, Inf. 387 ; Hudson,
Mn. M. Jn. xiv. 165.

PTYXID'IUM, Perty.— A genus of Eu-
chelia. It should probably be included in
LEUCOPHBYS.

BIBL. Pritchard, Infusoria, p. 615.

PUCCIN'IA, Persobn.— A'genus of Ure-
dinei (Hypodermous Fungi), containing
numerous parasitical species, growing upon
the leaves and other herbaceous parts of the
higher plants, forming "mildews," and with
their Uredinous forms, "rusts" &c. These
Fungi have received considerable attention
lately from Tulasne, De Bary, and others ;
and it appears that the genera Uredo and
others have no distinct existence, but are
preparatory forms of Puccinia and other
genera noticed under UBEDINEI. In the
article ^EciDiuM we have described the
twofold reproductive structures, namely the
spermogoma and the perithecia (figs. 6 & 6 a,
p. 19 ; PI. 26. figs. 1-4), producing respect-
ively the spermatia (supposed to have the
office of spermatozoids) and the spores. In
Puccinia three forms of reproductive organs
occur : first, spermogonia analogous to those
of ALcidium ; then the forms called Uredines
(chiefly of the supposed genus TricJiobasis),
producing globular unilocular bodies, shortly
stalked, and with transparent walls, but
with yellow or orange-coloured contents;
and lastly the true Puccinics, containing
bilocular spores borne on short stalks, and
having a dark-brown integument. The
latter present remarkable phenomena in
germination, which may be best observed
in those which sprout without becoming
detached from the matrix, such as P. gra-
minis, which however remain quiescent
until the spring folio wing their development,
while P. Glechom&jBuxi, Dianthi, and others
germinate in the same summer. The bilo-
cular spores have each one pore (analogous
to the pores of PoLLEN-grains), from which
extends a filamentous process, ultimately
giving rise to four short processes, each
terminating in a pointed process bearing a
sporidium, of more or less curved elliptical
form. About the time when these fall off,
the filament bearing the four processes be-
comes divided by septa into four chambers,
but then appears to die. The sporidia ger-
minate and produce a filament, which, in-
stead of becoming the basis of a mycelium,
reproduces a sporidium smaller than the first.
More is said respecting these remarkable
organisms under the head of UBEDINEI.

The PucdnicB present the following ge-
neral characters: — The spermogonia rare,
scattered on either face of the infested leaf.

PULKX.

[ 046 ]

PULKX.

•with an immersed, ostiolate peridiole, bear-
ing long cilia at the mouth ; pale, orange,
or blackish in colour. The Uredinous fruits
are scattered or grouped in circles, devoid
of a proper peridium, hut surrounded some-
times by thickish cylindrical paraphyses,
very rarely connected below into a mem-
brane, forming a kind of ciliated peridium ;
the stylospores are round and mostly spinu-
lose, with three or four equidistant pores.
The Puccineous fruits are also scattered or
grouped in circles, sometimes containing
only their proper spores, sometimes with
Uredinous spores intermixed, destitute of a
proper peridium, but, like the Uredines,
having sometimes a false envelope formed
of confluent paraphyses ; their spores, form-
ing the chief distinctive character of the
genus, are bttocidar, oblong or globose,
rounded-obtuse or acuminate at the apex,
smooth or spinulose, the upper loculus with
a pore at its summit, the lower with a pore at
the upper end of one side (next the septum).
These plants occur commonly on the
Grasses and many other herbaceous plants,
often changing colour during the summer,
being yellow or orange when the Uredinous
spores are ripe, and afterwards blackish
when the Puccineous form is mature.

The species are very numerous ; but some
of those formerly included under this name
are now removed to other genera, such as
UromyceSj Triphragmium, &c. (See URE-
DINEI.) P. graminis is common on corn
and other grasses (Milde.io) ; among the
other frequent species are P. Caricis, Poly-
gonorum, Menthte, Anemones, Buxi, £c.
Robin describes a Pu-ccima, apparently on
the authority of Ardsten, a Swedish phy-
sician, found upon the human head in FAVUS.
From his description it appears to be a true
Puccinia, and should hold its place (P. Favi,
Ardst.) among the species. But what is
more remarkable, it occurs together with
Achorion Schosnleinii, the latter presenting
itself as a constituent of the cups or crusts,
while the Puccinia occurs afterwards on the
desquamations of the epidermis.

BIBL. Berk. Br. Fl li. pt. 2. 363 ; Ann.
N. H. vi. 439; ibid. 2. v. 462, xiii. 461;
Tulasne, Ann. Sc. Nat. 3. vii. 12 ; ibid. 4. ii.
77, 138 & 182 ; LeVeiUe", ibid. 3. viii. 369 ;
De Bary, Brand.pilze, 36 ; Fries, Sum. Veg.
513 ; Robin, Vtytt. Parasit. 2. 613 ; Bagnis,
Jn. Mic. Soc. 1878, i. 27.

PULEX, Linn. (Flea>— A genus of In-
sects, of the order Siphoraptera (Suctoria
or Aphaniptera), and family Pulicidse.

Char. As there are only the single family
and genus in the order, the characters of
the latter are distinctive.

Head small (PI. 35. fig. 9), compressed,
rounded above, truncate in front, in some
species with an inferior pectinate fringe of
blackish-brown teeth; eyes one on each
side, round, simple, smooth ; behind each
eye is a cavity or depression, at the bottom
of which the antennae are attached ; an-
tennae (figs. 9 a, 12) four-jointed, their form
varying in the different species, the third
joint very minute, and forming the cup-
shaped base of the terminal joint or piece,
which in some species is furnished with
numerous transverse incisions, representing
as many distinct joints; in some the an-
tennae extend out of the depression, and are
carried erect.

Oral appendages (PI. 35. fig. 9 <?) composed
of several parts : 1. (PI. 33. figs. 32 d, 33 d)
The uppermost is single, and consists of a
thin, flattened seta, coarsely toothed on the
upper surface, and traversed throughout its
entire length by a canal, upon the walls of
which a very slender trachea runs, and from
which very minute canals, terminating at
the end of the little teeth, are given ofl'.
This is the suctorial organ, and pei'haps
corresponds to the labrum, but is sometimes
regarded as the lingua or ligula. 2. (figs.
32 /", 33 f} Two quadrangular, narrow, and
elongated, plates, each furnished with longi-
tudinal ribs, and with fine teeth ; these are
the lancets or scalpella, and correspond to
the mandibles. 3. (PI. 33. fig. 32 g} Two
somewhat triangular or leaf-like plates, the
maxilloe ; to which are attached— 4. (PI. 33.
fig. 32 h ; PL 35. fig. 9 d) Two nearly cylin-
drical four-jointed maxillary palpi. 5. (PL
33. fig. 32k; tig. 33 k) Two labial palpi, in
the form of sheaths, four-jointed, thickened
at the back and membranous at the margin ;
these palpi arise from near the apex of —
6. (PL 33. fig. 33 I) A small membranous
labium, with the still smaller mentum (PL
33. fig. 33 m) at its base.

Thorax composed of three segments, each
consisting of an upper (PL 35. fig. 9, c), and
a lower piece ff; from the lower arise the
corresponding legs. The two posterior seg-
ments of 1he thorax are each furnished with
a pair of plates, the hindermost of which is
longest, and nearly covers the sides of the
first and part of the second abdominal seg-
ment (fig. 9, behind /,/) ; these represent
rudimentary wings.

The legs are large, especially the hinder

PULEX.

[ 647 ]

PULEX.

ones, and adapted for leaping. The first
joint or coxa (Y/) is very thick; the second
or trochanter (k) is very smaU ; next come
the femur (2), the tibia (7c), and lastly the
five-jointed tarsus (/), which is terminated
by two curved and denticulate claws, with
a lobe or heel at the base.

The abdomen of the female has nine
distinct rings, the first seven of which are
each furnished with a pair of stigmata (a),
and consist of horny arches with mem-
branous margins. The eighth arch, which
has no membranous margin, is strengthened
by a horny band furnished with fine hairs,
to protect the orifice of the last stigma.
The ninth and last segment, called the
pygidium (fig. 9x and PI. 1. fig. 13), is
somewhat kidney - shaped or two - lobed,
folded on the dorsum, and exhibits twenty-
five to twenty-eight stiff and longish bris-
tles, implanted in the centre of as many
disk-like areolee, each of which is orna-
mented with a ring of rectangular or some-
what cuneate rays. The portions of the
pvgidium between the areolae are studded
with minute spines. The end of the abdo-
men in the female (PL 35. fig. 9) is more
rounded or ovate than that of the male
(fig. 13), which is somewhat turned up-
wards.

In some species the segments of the
thorax and abdomen are furnished with a
posterior pectinate fringe.

The alimentary canal is short and straight;
the stomach cylindrical ; the small intestine
as long as the "stomach, and the large intes-
tine short. Four short and broad Malpighian
vessels open into the lower orifice of the
stomach; and the ducts of two round salivary
vesicles unite to a single canal ascending in
a coiled form on each side of the oesophagus
towards the mouth.

The eggs of the flea are white, elongated,
and viscid outside. The larvae have no
legs ; they are elongated, resembling minute
worms, and very active, coiling themselves
into a circle or spiral, and serpentine in
their movements. The head is scaly, with-
out eyes, and supporting two very minute
antennae ; the body has thirteen segments,
with small tufts of hairs, and at the end of
the last are two little hooks.

The species are numerous (twenty-five,
Gervais) ; but their characters are not well
defined. One species (P. terrestris) is said
to exist under brush-wood; and one (P.
Boleti) in Boleti.

P. irritans, human flea. Pitch-brown ;

head shining, smooth, pectinate fringe ab-
sent ; legs pale ; femora of posterior legs
with hairs inside ; second joint of the tarsi
of the anterior pair of legs and first joint
of posterior tarsi longest. Tarsal joints, in
respective order of greatest length: an-
terior, 2, 5, 1, 3, 4 ; posterior, 1, 5, 2, 3, 4
(Bouche). We have not been able to find
a flea with the above relative length of the
joints of the anterior tarsi.

P. fells, cat's flea (P. canis, Bouche; PI.
35. fig. 9). Pale pitch-brown ; head naked,
shining, smooth, with delicate scattered
dots; coxae and femora almost naked;
fifth joint of anterior tarsi and first joint
of posterior tarsi longest. Tarsal joints:
anterior, 5, 2, 1, 3, 4; posterior, 1, 2, 5,
3,4.

P. canis or serraticeps, flea of dog and fox
(P.fefo, Bouche ; PI. 35. fig. 10, head). Pale
pitch-brown ; head shining, smooth, punc-
tate behind ; lower part of head and pro-
thorax with a pectinate fringe; posterior
tibiae much expanded at the end ; fifth
joint of anterior and first of posterior tarsi
longest. Tarsi : anterior, 5, 2, 1, 3, 4 ; pos-
terior, 1, 5, 2, 3, 4.

P. gallinte, fowl's flea. Pitch-brown,
with shining, smooth, elongated head ; pro-
thorax with a pectinate fringe; first joint
of all the tarsi longest. Tarsi: anterior and
posterior, 1, 2, 5, 3, 4.

P. martis, flea of the marten and dog.
Postero-inferior margin of head and pro-
thorax with pectinate fringe ; tarsi as in P.
canis.

P. sciuri, flea of the squirrel. Head
naked ; pectinate fringe on prothorax, none
upon the abdomen. Tarsi: anterior, 1, 5,
2, 3, 4 ; posterior, 1, 2, 5, 3, 4.

P. erinacei, flea of hedgehog. Head
naked, mesothorax with a fringe. Tar-d :
anterior, 5, 2, 1, 3, 4 ; posterior, 1 , 2, 5, 3, 4.

P. talpa, Curtis, flea of mole (PI. 35.
fig. 24).

P. columba, pigeon's flea. Prothorax
with pectinate fringe, none upon the abdo-
men ; antennas of male erect, those of the
female lying in the depression.

P.penetrans (Rhynchopriori), the chigoe or
jigger. The females burrow in the skin of
the feet ; and the ova, undergoing develop-
ment, enlarge the parent-abdomen to the
size of a pea, causing severe inflammation,
&c. Rostrum very long. Tropical.

P. vespertilionis, flea of the bat (PI. 35.
fig. 11, head); the first seven segments of
the abdomen with pectinate fringes.

PULLENIA.

[ 648 ]

PUSTUL1PORA.

P. pipistrellfs. The two first and the
seventh segments only with teeth.

BIBL. Westwood, Intr. ii. 489; Bouche",
Nov. Act. 1835, xvii. 501 ; Duges, Ann.
Sc. N. 1832, xxvii. 165 ; Gervais, Wakke-
naer's Apt. iii. 362; Denny, Ann. N. H.
1843, xii. 315; Landois, An. d. Hunde-
Flohs, 1867 ; Furlong, Mn. Mic. Jn. 1872,
263 ; Me"gnin, Paras'. 60 ; Taschenberg, D.
Ftihe, 1880.

PULLE'NIA, Parker & Jones.— A mi-
nute, globose, glassy, nautiloid Foraminifer,
near Globigerina ; snowing usually 4 or 5
chambers and a transverse slit-like aper-
ture ; an isomorph of Nonionina. Recent
and fossil.

BIBL. Carpenter, Introd. For. 184.

PUL VINULI'NA, Parker & Jones.— One
of the typical Rotalida. Shell with 7-30
cells; dense and delicately tubuliferous,
often limbate, sometimes prickly, granulate,
and stellate ; usually biconvex (P. repanda,
PI. 24. fig. 16) ; sometimes outspread, and
vermiculate (P.vermicularis, PI. 24. fig. 11);
septa single, little trace of canal-system ;
aperture large, arched or notched ; septal
face often coarsely perforated. Very nume-
rous species, recent and fossil.

BIBL. Carpenter, For. 310; Parker and
Jones, Phil. Tr. civ. 390.

PUNCTA'RIA, Greville.— A genus > of
Punctariaceae (Fucoid Algae), containing
three (one doubtful) British species, P. la-
tifolia, plantaginea, and tenuissima, growing
on rocks and stones, consisting of membra-
nous, olive or brown, ribless fronds, 4 to 12"
long, 1 to 3" broad, having a shield-like
organ of attachment at the base. The fruc-
tification consists of sori scattered all over
the fronds in minute distinct dots, com-
posed of roundish sporanges (producing
zoospores) intermixed with paraphyses;
these sporanges are called spores in most
works.

BIBL. Harvey, Mar. Alg. 41 and Phyc.
Brit. ; Greville, Alg. Brit. pi. 9.

PUNCTARIACELE. -A family of Fu-
coideae. Root a minute naked disk ; frond
cylindrical, or flat, unbranched, cellular,
with ovate sporanges intermixed with jointed
threads in groups on the surface. British
Genera :

Punctaria. Frond flat and leaf-like.
Sporanges scattered or in sori.

Asperococcus. Frond membranous, tubu-
lar, either cylindrical or compressed. Spo-
ranges in dot-like sori.

Litosiphon. Frond cartilaginous, fili-

form, subsolid. Sporanges scattered, almost
solitary.

PUS.— Popularly known as " matter;"
one of the products of inflammatory exuda-
tion.

Its general properties are too well known
to require description. Pus consists of an
albuminous liquid, containing a number of
minute corpuscles in suspension. These
consist of molecules and granules composed
of proteine compounds, fat or the earthy
phosphates, globules of fat of very various
sizes, and the proper pus-corpuscles or leu-
cocytes. Pus-corpuscles (PI. 38. fig. 4) are
spherical, from 1-2500 to 1-3500" in dia-
meter ; presenting a granular appearance on
the surface, and containing a number of
larger or smaller granules and a small
quantity of liquid. They are undistinguish-
able from the white corpuscles of the blood,
and may be considered as leucocytes. They
possess as protoplasmic masses the power
of spontaneous movement ; and migrate in
the tissues. They multiply by division.
When treated with acetic acid, they swell
up, and the granules become excessively
transparent, and ultimately vanish (PI. 38.
fig. 5), leaving from one to five, generally
two or three, round or oval nuclei, which
mostly present a dark margin and light
centre, giving them a cupped appearance,
indicating a diminution of refractive power
in the centre. The cupped centre is some-
times seen in the nuclei without acetic
acid, after the action of water only.

In the pus of chronic abscesses, unhealthy
ulcers, &c. the corpuscles are often few, de-
formed and mixed with numerous granules
of proteine, fatty and calcareous matters,
crystals of cholesterine, of the ammonio-
phosphate of magnesia, and sometimes
monads and vibrios ; exudation-corpuscles
are occasionally present also.

Pyoid corpuscles. — Under this term
Lebert describes a modification of pus-cor-
puscles, consisting of a tolerably transparent
envelope, enclosing from eight to ten or
more small globules (PI. 38. fig. 6). Acetic
acid does not alter them, or at most only
renders them slightly more transparent.
The small globules are composed of a pro-
teine-compound ; for they are soluble in
potash.

BIBL. That of CHEMISTRY, Animal; and
Lebert, Phys. Path.-, Rindfleisch, Path.
Hist. ; Green, Morb. Anat.

See INFLAMMATION.

PUSTULIP'ORA, Blainville.-A genus

PYCNIDIA.

[ 649 ]

PYXICOLA.

of Infundibulate Cyclostomatous Polyzoa,
family Tubuliporidae.

Char. Zoary erect, cylindrical ; cells half-
immersed, arranged on all sides 5 orifices
prominent.

Two British species — P. proboscidea, and
P. deflexa. The latter common on shells
from deep water.

BIBL. Johnston, Br. Zooph. 278 ; Gosse,
Mar. Zool. ii. 8.

PYCNIDIA.— A term applied to the
receptacles enclosing stylospores in the
LICHENS and FUNGI.

PYCNOG'OXUM.— A genus of Podo-
somata, Sea Spiders, which are usually
placed amongst the Crustacea, but by some
authors amongst the Arachnida. They have
no special respiratory organs, and only four
pairs of legs. They sprawl over seaweed,
and hide under stones. There is a pair of
chelate mandibles.

PYCXOPHY'CUS, Kiitz.— A genus of
Fucaceae (Fucoid Algae), containing one
British species, P. (Fucus) tuber culatus; re-
moved from Fucus on account of its cylin-
drical frond, the compact cellular substance
of the receptacles, and the ramified fibrous
pseudo-root. The fructifications, formed at
the ends of the dichotomous lobes of the
frond, are elongate, cylindrical, more or less
tuberculated, and with numerous pores
opening from conceptacles containing spore-
sacs and antheridia (together), resembling
in general those of Fucus. The spore-sacs
are collected at the bottom of the concep-
tacles, the antheridia at the upper part.
See Fucus.

BIBL. Harvey, Mar. Alg. 18 ; Phyc. Br.
89 ; Decaisne and Thuret, Ann. Sc. N. 3.
iii. 5 ; Thuret, ibid. xvi. 10.

PYGED'IUM.— The last segment of the
abdomen of certain insects. It exhibits a
curious structure in Pulex (p. 647) ; the
same is stated to occur also in Chrysopa,
the lace-winged fly, the locust &c. (Davis.
Jn. Mic. Soc. 1879, ii. 252.)

PYRAMID'IUM, Bridel.— A genus of
Funariaceae (Acrocarpous Mosses), allied to
Funaria in habit, but differing in important
points.

Pyramidium tetragonum, Brid. = Gymno-
stomum tetragonum, Schwagr.

PYRENID'lUM, Nyl.— A genus of Col-
lemaceous Lichens.

Char. Thallus minute, stellato-divided ;
apothecia pyrenocarpous, verrucarioid. P.
actinellum ; on chalk. (Leighton, Lick. Fl.
36.)

PYREXODEL— A series of Lichenacei.

Char. Fructification in closed receptacles.

BIBL. Leighton, Lich. Flora, p. 2.

PYREXOMYCE'TES.— That portion of
the Ascomycetous and Coniomycetous Fungi
having a closed, nuclear fruit ; standing
opposed to the Discomycetes, with open
fruits, like the Angiocarpous and Gymno-
carpous Lichens. Now sunk in Sphseriacei.

PYRENOP'SIS, Nyl.— A genus of Col-
lemaceous Lichens. 8 species; on rocks.
(Leighton, Lich. Flora, 14.)

PYRENO'THEA, Fries.— A genus of
Limborieae (Angiocarpous Lichens), con-
taining a number of species separated from
Veri°ucaria, on account of the spores being
free in the perithecia and not developed in
thecae. The bodies taken for spores, how-
ever, are spermatia contained in spermo-
gonia, the sporiferous perithecia being
apparently unknown (see LICHENS).

BIBL. Leighton, Ang. Lichens, 65; Tu-
lasne, Ann. Sc. N. 3. xviii. 217.

PYRSONE'MA, Leidy.— A genus of
Holotrichous Infusoria. Body fusiform,
with a cord-like longitudinal undulating
"border. P. vertens, in the intestine of the
white aut(Termes); length 1-200". (Kent,
Inf. 554.)

PYRULI'NA, D'Orb.— A neat acuto-
pyriform Polymorphina. Fossil in the
Chalk, and German Tertiaries.

BIBL. D'Orbiguy, Mem. Soc. Geol. Fr.
iv. 43 ; Bradv, Parker and Jones, Linn. Tr.
xxvii. 219.

PYTHIUM, Pringsheim.— A supposed
genus of parasitic Unicellular Algae, the
true nature of which, however, is yet
doubtful.

P. entophytum (PI. 5. fig. 8) occurs in
this country in diseased cells of Confervoid
Algae. It consists of minute flask-shaped
bodies, taking the place of the proper cell-
contents, finally pushing the neck-like por-
tion through the wall of the cells, outside
of which it bursts and discharges active (?)
molecules, which Pringsheim regards as
gonidia. P. monospermum grows upon
insects in water, in the manner of Achlya ;
and he refers this genus to the family
Saprolegnieae.

BIBL. Pringsheim, Jahrb. wiss. Bot. i.
289; Carter, Ann. N. H. 2. xvii. 101;
Henfrey, Tr. Mic. Soc. New Series, vii. 25 ;
Currey, Mic. Jn. v. 211 ; Rabenht. Alg. iii.
276.

PYXIC'OLA, Kt,— A genus of Peritri-
chous Infusoria; like Cothurnia, but with

PYXIDICULA.

[ 050 ]

QUININE.

an operculum. Several species ; fresh and
salt water. (Kent, Inf. 725.)

PYXIDIO'ULA, Ehr.— A genus of Dia-
tomacene.

Char. Frustulea single, free or sessile ;
valves circular, convex, hoop absent.

Numerous species have been described —
one f r. wat., one marine, the remainder fossil,
found in America.

Ilabenhorst reduces the species to P. major,
adriatica, and a doubtful form, P. Naeyelii.

P. major (PL 25. fig. 13). Valves' coni-
cal, regularly punctate. Diameter 1-420" ;
freshwater.

P. adriatica. Fr. sessile ; valves near y
hemispherical, free from markings (ord. ill ).
Upon marine Algae. Diam. 1-000' '.

P. minor=Cyclotella operculata.

The bodies represented in PL 25. fig. 12,
found in flint, have been described as P.
globator, Pritch. (not P. ylobosm, Ehr.) ;
they do not, however, appear to belong to
the Diatomaceae.

Kiitzing places Stephanopyxis and Xan-
thiopyxis here.

BIBL. Ehr. Inf. 165, and Her. Berl. Ak.
1844 & 1845 ; Kiitz. Bacill.ol, and Sp. Alg.
21 ; Pritchard, Inf. 482.

PYXID'IUM, Kt.— Like Operctdaria,
but solitary. Two species ; freshwater ;
on Entomostraca and Confervas. (Kent,
Inf. GOG.)

'PYXILLA, Grev.— A genus of Diato-
macene.

BIBL. Grev. Mic. Trans. 1865, 2.

Q.

QUARTZ. See ROCKS.

QUILL. — The quill of feathers possesses
considerable polarizing power; the coloured
bands, however, are so broad that they are
better seen with the naked eye.

See FEATHERS.

QUININE. See ALKALOIDS.

lodo-disulphate, sulphate of iodo-quinine,
Herapathite. — This remarkable salt is pre-
pared by dissolving disulphate of quinine in
strong acetic acid, warming the solution,
dropping into it an alcoholic solution of
iodine carefully in small quantities at a
time, and placing the mixture aside for
some hours, when the crystals separate.

They dissolve in the heated mother-liquor,
also in hot alcohol, being again deposited
on cooling ; but they are not soluble in cold
alcohol or ether.

They are so easily decomposed and altered,
that thev are with difficulty mounted. This

; may, however, be effected by cautiously
i neutralizing the excess of acid in the mother-
liquor by solution of ammonia, taking care
; not to precipitate the excess of the disulphate
j of quinine ; a portion of the liquid contain-
j ing the crystals is then transferred to a slide,
the liquid removed with blotting-paper, and
the crystals dried in a current of cold air.
They are then mounted in Canada balsam,
rendered thin with ether, heat being avoided.
The crystals are of a pale olive-green
colour (PI. 11. fig. 17), and possess a more
intense polarizing power than any other
known substance. The play of colours pre-
sented when they are rolling over each other
whilst contained in a watch-glass, forms a
very beautiful sight, the colours varying
according to the relative positions of the
crystals to each other ; and when the latter
cross each other at a right angle, complete
blackness is produced.

Herapath, who discovered this beautiful
salt, has described a method of making
crystals of sufficient size to replace tourma-
lines or Nicol's prisms. The ingredients
are : — as pure disulphate of quinine as can
be obtained, that from Howard and Kent
being best ; strong acetic acid, of sp. gr.
1'042 ; proof spirit composed of equal bulks
of rectified spirit of sp. gr. *837 and dis-
tilled water ; and tincture of iodine, made
by dissolving 40 grains of iodine in 1 oz. of
rectified spirit. The proportions are :

Disulphate of quinine. . 50 grains.

Acetic acid 2 fluid ounces.

Proof spirit 2 fluid ounces.

Tincture of iodine .... 50 drops.

The disulphate of quinine is dissolved in the
acetic acid mixed with the spirit, the solu-
tion heated to 130° F., and the tincture of
iodine immediately added in drops, the
mixture being constantly agitated.

The compound should be prepared in a
wide-mouthed Florence flask ; and the tem-
perature should be maintained for a little
time after the addition of the iodine, so that
the solution may become perfectly clear,
and of a dark sherry-colour. It should
then be set aside to crystallize in a room of
a uniform temperature of 45° to 50° F.,
and kept from vibration. The latter may be
effected by suspending the flask by the neck
with strong string, attaching this to a hori-
zontal cord stretching across the room from
one wall to the other ; or placing the flask
on a steady support, lying upon a pillow.
The large crystalline plates form upon the

QUIXQUELOCULIXA. [ Ql

surface of the liquid, where they are allowed
to remain for twelve to twenty-four hours,
until they have acquired sufficient thickness.
The flask is then carefully removed without
shaking, and rested upon a gallipot. A
circular cover is next fastened by its edge to
the end of a glass rod with a little wax or
marine glue, and passed beneath one of the
crystalline films, the adherent mother-liquor
removed with blotting-paper, and the film
allowed to dry in a room at a temperature
of 45° to 50° F. The cover and film are
then placed under a small bell-glass, with a
watch-glass containing a few drops of
tincture of iodine. The time required for
the iodizing may be about three hours at
50° F., or less if the temperature be higher.
The film is then covered with a solution
of Canada balsam, in ether, saturated with
iodine by warming with a few crystals of
this substance, and allowing it to cool.

Other films are removed and mounted in
the same manner. Should the films not
separate from the original liquid at the end
of six hours, this must be heated with a
spirit-lamp until the deposited crystals are
dissolved, a little spirit and a few drops
more tincture of iodine added, and the
liquid again set aside.

If the film appear black when removed
on the cover, it is crossed by an adherent or
interposed crystal, which must be carefully
removed.

These crystals are sold ready mounted,
and may be purchased at a very small cost.
Herapath proposes the production of the
crystal of the quinine-salt as a very delicate
test for the presence of quinine. A test-
liquid is first made wTith 3 drachms of
acetic acid, 1 drachm of rectified spirit, and
6 drops of dilute sulphuric acid. A drop of
this is placed upon a slide and the alkaloid
added, and, when it is dissolved, a very
minute quantity of tincture of iodine added ;
after a time the salt separates in little
rosettes.

BIBL. Herapath, Phil. Mag. 1852, iii.
161, iv. 186, and 1853, vi. 171 & 346;
Haidinger, ibid. 1853, vi. 284.

QUINQUELOCULI'NA, D'Orb.— One
of the modifications of Miliola, having its
chambers aggregated on two opposing faces,
as in Spiroloculina, but with their edges
more extended on the one side than on the
other, so that only three chambers are ap-
parent on one side, and five on the other.
Numerous Quinqueloculince occur recent
and fossil. Q. scminulum (PI. 23. fig. 5)

] RALFSIA.

is common in the European seas. Q.
Bronyniartii (fig. 6), having delicate striae,
is not uncommon in warmer seas.

BIBL. Williamson, Foram. 85 (MilioKna) ;
Carpenter, For. 78.

R.

RACO'DIUM. See ANTENNARIA.

RACOMIT'RIUM = TRICHOSTOMUM pt.

RADIOLA'RIA, Miiller.— An order of
Rhizopoda, including the Polycystina,
Acanthometrina, Thalassicollida, and Acti-
nophryina. They possess a siliceous test or
siliceous spicules, a central capsule and
peculiar yellow cells, and are provided with
long, protruding, radiating pseudopodia
which occasionally form meshes. See the
Families and RFIIZOPOBA.

BIBL. Haeckel, Radiolarien, 1862 ; Greef,
Arch. mik. An. 1869, 1875.

RAD'ULA, Dumort. — A genus of Jun-
germanniese (Hepaticae), containing one
British species, .R. complanata (fig. 613),

Fig. 613.

Badula eomplanata.

Leafy shoot with an immature and a burst capsule.
Magnified 5 diameters.

common upon the trunks of trees, every-
where, forming orbicular pale-green patches
closely appressed to the bark.

BIBL. Hook. Br. Jung. pi. 81 ; Br. Flor.
ii. pt. 1. p. 120 ; Ekart, Syn. Jung. pi. 4.
fig. 31; Endlicher, Gen. Plant., Supp. 1.
No. 472. 13 ; Leitgeb, Ber. Wien. Ak. 1871.

RAD'ULUM.— A genus of Hydnei (Hy-
menomycetous Fungi), consisting of a few-
species with irregular compressed teeth or
rude irregular tubercles. -R. orbiculare is
not infrequent on fallen branches of birch
and other trees, assuming various forms.

BIBL. Fr. EL 148; Berk. Outl. 263;
Cooke, Hanrfb. 304.

RALFSIA, Berk.— A genus of Myrione-

RAMALINA.

[ 652 ]

RAPHIDES.

maceae (Fucoid Algae), containing one Bri-
tish species, R. verrucosa (R. deusta, Berk.),
forming dark-brown Lichen-like patches, 1
to 6" in diameter, on rocks between tide-
marks. The fronds are at first orbicular and
concentrically zoned ; they are composed of
densely packed, vertical, simple, jointed fila-
ments. The fruit is formed in wart-like
patches, and consists of obovate sporanges
attached to the bases of vertical filaments.

BIBL. Harvey, Mar. Alg. 49.

RAMALINA, Ach.— A genus of Rama-
loidei (Lichenaceous Lichens), containing
13 British species, of shrubby habit, mostly
growing upon the trunks of trees, bearing
orbicular-peltate apothecia, nearly of the
same colour as the thallus. It. fraxinea,
fastigiata, andfarinacea are common.

BIBL. Hook. Br. Fl. ii. pt. 1. 228;
Tulasne, Ann. Sc. Nat. 3. xvii. 192.

RAMULI'NA, R. Jones.— A tubular
branching Hyaline Foramiuifer, swollen
here and there into chambers, whence the
branches or stoloniferous tubes proceed at
varying angles to other such chambers. R.
aculeata, D'Orb., R. l&vis, and brachiata,
Jones, are known from the Chalk ; R. ylobu-
lifera, Brady, has a wide distribution in the
Atlantic and Pacific.

BIBL. Rupert Jones, Proc. Belfast N. F.
Club, 1875, n. ser. i. 88 j Brady, Jn. Mic.
Sac. n. ser. xix. 272.

RA'NA,Linn. See FROG.

RAPH'IDES.— This name was first ap-
plied to the minute needle-shaped crystals
occurring in great abundance in the tissues
of many plants ; but it is now generally
applied to all the crystalline formations
contained in vegetable cells. The crystals
are either solitary or grouped ; and some-
times the groups are formed on a peculiar
stalked matrix projecting into the cavity of
enlarged cells, forming the organs called
cystoliths.

There are few plants of the higher classes
which do not contain raphides : they are
very abundant in the herbaceous structures
of the Monocotyledons generally, and espe-
cially those of the Aracese, Musaceae, Lilia-
ceae, &c. ; they also abound in the Polygo-
nacese, Cactaceae, Euphorbiaceae, Urticaceae,
&c., among the Dicotyledons. They are
usually found only in the interior of the
cavities of cells, but in some cases they occur
in the intercellular cavities, or in the cell-
walls. They may occur in almost any
part, but are found most extensively in the
steins of herbaceous plants (Monocotyledons

in general and Cactaceae); they also occur
in the bark and pith of many woody plants
(lime, vine) ; leaves likewise frequently con-
tain them in vast numbers (Aracese, Mu-
saceae, Liliaceae, Iridaceae, Polygonaceoe) ;
also sepals (Orchidaceae, Geraniaceee) ; in
the rhubarbs, and also in Umbelliferae, they
occur extensively in the roots, for instance
in the carrot ; and they abound in autumn
in the base of the bulbs of the onion and
other Liliaceae. Raphides are often very
readily discovered and clearly seenin tissues,
by the aid of the polarizing apparatus.

The form of the needle-shaped raphides
is usually that of a square prism with pyra-
midal ends. These ordinarily occur lying
parallel in bundles (fig. 614) ; another com-
mon form is that of rectangular or rhombic
prisms with oblique or pyramidal ends ; the
smaller of these often present themselves in
groups radiating from a centre (fig. 615).
Prisms of similar or of six-sided forms,
octahedra, rhombs, &c. also occur singly or
few together (PI. 48. fig. 28), the larger
ones sometimes nearly filling the cavity of

Fig. 614.

Fig. 615.

Fig. 614. Parenchymatous cells of the stem of Rumex,
containing bundles of raphides. Magnified 400 diaim.

Fig. 615. Parenchvmatous cells of the stem of Beta,
with groups of raphides (Sphaeraphides). Magnified
400 diams.

the cells in which they lie. Rhombic
crystals of oxalate of lime occur in the
parenchymatous cells surrounding the vas-
cular bundles in the bracts of Medicago
trigonella ; and Gulliver has shown the
crystal in each cell of the testa of the elm.
The cells containing the bundles of acicular
raphides in the Araceae also contain a viscid
sap, which causes them to burst, through
endosmose, when placed in water, and dis-

EAPHIDES.

[ 053 1

RATTULUS.

charge the crystals. Turpin erroneously
described these as organs of a special nature,
under the name of Biforines.

Raphides most frequently consist of oxa-
late of lime, especially in the Cactacese,
Polygonaceae, &c. ; carbonate of liine seems
to stand next in the order of frequency,
mostly in the form of granules, only recog-
nizable under polarized light with the
crossed nicols ; then sulphate and phosphate
of linie. Their composition may be ascer-
tained by the appropriate tests for these
salts. It is sometimes difficult to determine
the form accurately, on account of the small j
size ; it is found "advantageous to mount
well-cleaned and partly crushed crystals in
Canada balsam, also to view them rolling
over in alcohol (!NTB. p. xxxiii).

The peculiar crystalline structures called
cystoliths, occur most abundantly in the
families of the Urticaceae (including Moreae)
and the Acanthaceae. They ordinarily con-
sist of a stalked, clavate, and globose, or
irregular linear body, suspended in a greatly
enlarged cell, most frequently situated
beneath the epidermis of the leaf (PL 48.
figs. 26, 27) ; but they also occur in deeper-
seated regions. Their nature and develop-
ment have been followed by several ob-
servers ; and they are found to consist of a
cellulose matrix with carbonate of lime crys-
tallized in a kind of efflorescence upon the
surface. They appear to originate by a little
papilla or column of secondary deposit at
the upper end of the cell, which increases
by successive concentric layers of cellulose
applied on the lower surface, leaving a short
stalk-like portion which remains uncovered
and also free from the crystals which gradu-
allv sprout out from the thickened head.
The crystals may be removed by the action
of acid ; and then the matrix assumes a blue
colour with sulphuric acid and iodine. Payen
imagined the thicker portion incrusted by
the crystals to be composed of numerous
cellules, eacli producing a crystal : this is
erroneous. The cystoliths vary in form :
the clavate kinds may be best observed in
Ficus elastica (PI. 48. fig. 27) and other
species, in vertical sections of the leaf;
globular forms are found in Parietaria offi-
cinalis (fig. 26) and the Hop ; in species
of Pilea they are linear or crescentic, and
suspended by the convex edge.

BIBL. Turpin, Ann. Sc. Nat. 2. vi. 5 ;
Dyer, Qu. Mic. Jn. 1872, 288 ; Quekett, Tr.
Mic. Soc. new ser. i. 20 ; Gulliver, Sci.
Gossip, 1873 ; Ann. N. H. 1865 ; Qu. Mic.

Jn. 1866, 1869, 1873; M. M. Jn. x. 259'
xviii. 143 ; Lankester, Q. M. J. 1863, 243 '•>
Urban, Bot. Zeit. 1873, 266; Sanio, Monatsb.
Berl. Ak. 1857; Hanstein, ibid. 1859;
Holzner, Flora, 1864; Hilgers, Pringsheim's
Jahrb. vi. 1867 ; Rosauoff, Bot. Zeit. 1867 ;
Solms-Laubach, ib. 1874; Pfitzer, Flora.
1872 ; Sachs, Bot. 66.

RAPHIDIOPH'RYS, Archer.— A genus
of Rhizopoda.

Char. Bodies green, spherical, aggregate,
surrounded by a common investment of
cloudy buff-coloured sarcode, containing
slender, hyaline, circular, siliceous spicula.
Pseudopodia arising from the sarcode
between the spicula, long, straight, and very
thin ; they never coalesce.

BIBL. Archer, Freshw. Rhiz.. Qu. Mic. Jn.
1869, 1871.

RAPHID'IUM, Ktz.— A genus of Uni-
cellular Algse. Cells fusiform or cylindrical,
acuminate, straight or slightly curved, with
green cell-contents. The species are those
of Ankistrodesmus, Closterium, Micrasterias,
and Scenedesmus of other authors.

Rabenhorst regards our Closteritim Griff.
(PL 14. figs. 57, 58) as It. aticulare.
BIBL. Rabenht. FL Eur. Alg. iii. 44.
RAPHIG'NATHUS, Duges.— A genus
of Acarina, family Trombidina.

Char. Palpi long, with an indistinct
claw ; mandibles represented by two short
setae inserted upon a fleshy bulb, concealed
by a broad labium ; body entire : coxae
contiguous ; legs but little attenuated at the
ends, anterior longest, last joint longer than
the others.

R. ruberrimus (PL 6. fig. 35 a, labium with
mandibles and a palp ; b, a mandible).
Body oval, slightly depressed, smooth, and
almost free from hairs, rostrum forming a
conical process; eyes two, dark red, one on
each side at the anterior part of the body ;
labium triangular, concave ; setae accom-
panied by a more slender hair-like process ;
pal pi large, inflated, clawof the 4th jointvery
short. Found under stones and on plants.
JR. hispidus. Form, that of the preceding ;
body velvety, with two posterior papillae.
BIBL. Duges, Ann. Sc. Nat. 2. i. 22, ii.
55 ; Gervais, Walckenaer's Apter. iii. 172 ;
Murray, EC. Ent. 114.

RAT'TULUS, Lamarck.— A genus of
Rotatoria, of the family Hydatinaea.

Char. Eyes two, frontal; tail-like foot
simply styfiform ; neither cirri nor fins pre-
sent. Teeth indistinct.

R. lunaris (PL 44. fig. 22). Eyes distant

REBOUILIJA.

[ 054 ]

REPTOMONAS.

from the anterior margin ; foot decurved,
lunate; freshwater; length 1-288".

BIBL. Ehrenberg, Infus. 448 ; Pritchard,
Infusoria, 688.

'REBOUIL'LIA, Raddi. — A genus of
Marchantieae (Hepaticae), founded on Mar-
chantia hemisphcerica, Linn., characterized
by the conical or flattened, !-• 5-lobed stalked
receptacle (fig. 616), the perigone being ad-
herent to the lobes of the receptacle on the
under side, opening by a slit (fig. 617) ;

Fig. 616.

Fig. 617.

Hebouillia hemispherica.

Female receptacles, with the perigone burst.

Fig. 616, seen from above ; Fig. 617, from below.

Magnified 2 diameters.

perichjete none, and the globose sporange
bursting irregularly. The antheridia are
imbedded in sessile, crescent-shaped disks.
The fronds are rigid, with a well-marked
midrib, green above, purple beneath. It
grows on moist banks, or by the side of
mountain-streams.

BIBL. Hook. Br. Fl ii. pt. 1. 108 ; Bis-
choft', Nova Acta, xvii. 1001, pi. 69. fig. 1 ;
Endlich. Gen. Plant. No. 468.

RECEPTACLES FOR SECRETIONS.
See SECRETING ORGANS of Plants.

RED SNOW.— The remarkable pheno-
menon known under this name has been the
subject of very extensive investigation, and
it is well known to be the result of the
enormous development of a microscopic
organism related to Pi'otococcus or Chlami-
dococcus viridis. We are inclined to believe
that more than one form is comprehended
at present under the name of Protococcus or
Hcematococcus nivalts; for our specimens of
Arctic red snow, for which we were in-
debted to the kindness of R. Brown, appear
to belong to the same genus as Palmella
cruenta, as first indicated by Brown, and
confirmed by Sir W. Hooker. Greville's
figures of the Scotch plant closely resemble
this ; but the continental plants described by
Shuttle worth and others would seem conge-
neric with Protococcus, Chlamidococcus, and
Chlamidomonas, since they produce active
zoospores, the forms which Shuttleworth

described as distinct Infusoria, as species of
Astasia. Nearly connected with this con-
tinental snow-plant, if not identical, is the
Protococcus pluvialis, described so elaborately
by Colin, which moreover appears to be
synonymous with the Discercca purpurea of
Morren.

The following is a description of the i
snow, brought home by Capt. Parry, from
our own observation. It may be noticed as
remarkable that, after being' kept so many
years in a moist state in a stoppered bottle,
the structure appears almost unrhn> .
only difference being the assumption «
green colour on the surface of th>
when exposed to light. Frond an indefinite
gelatinous mass densely filled with spherical
cells, about 1-200" in diameter (PI. 7. tig.
3d) ; cells with a distinct membrane, their
contents consisting of numerous tolerably
equal granules, red or green (see ab<>\
Between the large cells lie patches of nii-
nute red granules (as in Palnn-fln cruenta,
PI. 7. fig. 3 a, b), apparently dischai -ged from
the large cells. Bauer and (ireville both
describe this as the mode of propagation of
the plant; but it is probable that the (
also increase by division when acth «
getating.

BIBL. Brown, Appendix t<> Ross's 1.^
Voyage, 1819; Det'andolle, Bihl. miiv.
Geneve, 1824 ; Hooker, Append, to J'urry's
Second Voyage ; Greville, Cn/pl. Fl. pi. i':!! ;
Shuttleworth, JJibl. univ. Geneve, 1840;
Morren, Mem. Acad. L'r/r.rclle*, \i\.
Flotow, Nora Acta, xx. 11; Colin, front
Acta, xxii. 60-">.

RENULI'NA, Blake.— Minute Pubgld-
bular, hollow, calcareous bodies, 1-200" in
diameter, often silicified, entering largely
into the composition of the Coralline Oolite ;
regarded as probably organic by Sorby, and
referred to the Foraminifera by Blake.
(Sorby, Qu. Geol. Jn. vii. 1851, 1 j Blake,
Jn. Mic. Soc. 1876, 262.)

RENULI'TES, Lam. (Xenulfna, Blain-
ville). — A broad, reniform modification of
Vertebralina, one of the Porcellaneous Fora-
minifera.

BIBL. Carpenter, Introd. For. 74.

RE'OPHAX, Montfort.— A simple, uui-
serial subspecies of Lituola, straight or curved,
chambers often angular or nigged in outline.
Abundant in many seas. (Parker and
Jones, Ann. N. H. 3. vi. 346 ; Brady, Qn.
Mic. Jn. n. s. xix. 51.)

REPTOMONAS, Kt— A genus of Rhizo-
Flagellate Infusoria. Creeping; fiagellum

RESERVOIRS.

[ 655 ]

RHABDOSTYLA.

single, pseudopodia arising from the postero-
ventral surface. R. caudata-, in hay-infu-
sions, and decaying grass 5 length 1-1000".
(Kent, Inf. 223.)

RESERVOIRS FOR SECRETIONS
IN PLANTS. See SECRETING ORGANS of
Plants.

RETE MUCOSUM. See SKIN.

RETEP'ORA, Lamk.— A genus of In-
fundibulateCheilostomatous Polyzoa, family
Escharidae.

Char. Zoary leafy, reticular, fragile ; cells
on one surface only, short, and not promi-
nent. Two British species :

R. reticulata. Wavy and convolute, upper
side warty and very porous.

R. Bcaniana. Umbilicate, funnel-shaped,
wavy; interspaces unarmed.

BIBL. Johnston, JBr. Zooph. 353 ; Gosse,
Mar. Zool. 18 ; Hiucks, Polyzoa, 388.

RETICULA'RIA, Bull.'— A genus of
Myxomycetes (Gasteroniycetous Fungi)
characterized by the indeterminate, thin
simple peridium, bursting irregularly, with
the branched, shrubby, reticulated capilli-
tium adherent to it. Several species are
British ; they are rather large plants, grow-
ing over recently felled timber or on hollow
trees, rails, &c., with great rapidity.

BIBL. Berk. Sr. Fl. ii. pt. 2. 308 ; Fries,
Sum. Veg. 449 ; Syst. My col. iii. 83.

RETICULA'RIA, Carpenter.— Rhizo-
poda with long slender pseudopodia, which
meet and reticulate : as in Lieberkuehnia, and
other FORAMINIFERA.

BIBL. Carpenter, Introd. For. 28; Mici-o-
scope, 476.

RETINA. See EYE.

RHABDAM'MINA, Sars.— A relatively
large Arenaceous Foraminifer, usually tri-
radiate, but sometimes with four or even
five hollow rays or tubes, and sometimes
consisting of only the central chamber elon-
gated on two sides, forming one tube swollen
in the middle. R. abyssorum, Sars, At-
lantic and Pacific ; R. linearis, Brady, West
Indies and South Atlantic, at great depths.
(Carpenter, Soiree, Mic. Soc. 1870, 5 ; Brady,
Jn. Mic. Sc. n. s. xix. 37.)

RHABDI'TIS, Duj. See ANGUILLULA.

RHABDOGO'NIUM, Reuss.— A three-
or four-angled Orthocerine Foraminifer.

BIBL. Reuss, Sttz. Ak. Wien, xliv. 367.

RH ABDOLITH ES, Schmidt.— Minute,
subcylindrical, calcareous bodies, about
1-3000" length, usually consisting of a rod
and a terminal circlet of smaller rods
(1-25000"), simple or confluent. Abundant

with coccoliths in the mud of the Adriatic ;
and fossil with the same in the chalk of
Manitoba and Nebraska. Found also in the
ocean-ooze by W. Thomson, and referred
by him to small floating spherules (possibly
vegetables) formed by their attached bases,
and termed by him Rhabdospheres. (Schmidt,
Sttz. Ak. Wien, Ixii. 669, and Ann. N. H.
4. x. 369 j Dawson, Canad. Nat. vii. 256 ;
W. Thomson, The Attlantic, i. 221.)

RHABDONE'MA, Kiitz.— A genus of
Diatomacese.

Char. Frustules tabular, depressed, com-
pound, fixed by a stalk arising from one of
the angles, with interrupted vittae (front
view), vittas capitate ; valves transversely
striate, striee extending into the front view,
and forming numerous longitudinal series.

Marine; upon Algae. Striae visible under
ordinary illumination ; the dark lines or
yittae correspond to more or less complete
internal septa; frustules connected with
each other by gelatinous cushions (isthnii).

Conjugation and the formation of sporan-
gia have been observed.

R. arcuatum (Striatella arcuat., Ralfs)
(PI. 17. fig. 18). Vittae in two marginal
rows, isthmi convex. Length 1-300''.

R.minutum (Tessella catena, Ralfs). Vittaa
in two marginal rows ; transverse striae faint.
Length 1-1200 to 1-960".

R. adriaticum. Vittae forming four rows
(interrupted in the middle, and again
between the middle and the margin on each
side) ; transverse striae distinct ; isthrni con-
cave. Length 1-480 to 1-170".

BIBL. Kiitzing, Bacill. 126. and Sp. Ala.
115 ; Ralfs, Ann. N. H. xi. 455, and xii.
104 ; Smith, Diat. ii. 32 ; West, Micr. Jn.
1858, 186; Arnott, Micr. Jn. 1858, 91:
Rabenht. Alg. i. 305.

RHABDOPLEU'RA, Allman.— A genus
of Polyzoa according to Allman, and of
Hydroida according to Sars. Zoary tubular,
creeping or incrusting, septate, annulate,
bodies with an oral disk. It connects the
two classes, and presents many features of
great interest. Allman considers that its
polypary resembles that of the Graptolites.
Two species, on shells from deep water.

BIBL. Allman, Qu. M. Jn. 1874 ; Sars,
Qu. M. Jn. 1874, 23 j Lankester, Qu. Mic
Jn. 1874, 77; Hincks, Polyz. 577.

RHABDOSTY'LA, Kt.— A genus of
Peritrichous Infusoria. Solitary, like Vorti-
cella, but with a rigid, short pedicle. Seven
species; salt or fresh water. (Kent, Inf
664.)

RHAGADOSTOMA.

[ 656 ]

RHIZOCLONIUM.

RIIAGADOS'TOMA, Korb.— A genus
of Micro-lichens parasitic on the thallus of
Solorina crocea. Spores 2-4, in lanceolate
fugacious thecae, large, simple, becoming 2-
locular, colourless. (Lindsay, Qu. Mic. Jn.
1869, 344.)

RHAPHIDOGL(E'A,Kutz.— Agenusof
Diatomaceae.

Char. Frustules navicular, arranged in
radiating crowded rows in a globose gelati-
nous mass. Marine.

R. micans (PI. 19. fig. 11). Rows of frus-
tules irregular, obsolete ; valves linear-lan-
ceolate, subulate, somewhat acute. Length
1-140".

Three other species.

BIBL. Kutzing, BarilL 10 ; id. Sp. Alg. 97.

RAi'HIUOMONAS, Stein.— A genus of
Flagellate Infusoria. Free, green, Hagellum
single ; mouth anterior, with a defined pha-
rynx ; an anterior row of trichocysts. R.
semen = Monas s.} Ehrb. ; length 1-500";
marsh-water, among decaying Sphaynum.
(Kent, Inf. 391.)

RHAPHONE'IS, Ehr.— A genus of Dia-
tomacese.

Char. Frustules single, quadrangular, na-
vicular ; valves without a median aperture
(nodule?) ; median sutural line longitudinal.
Marine. = Doryphora without a stalk.

Eleven species.

BIBL. Ehrenberg, Ber. Berl. Akad. 1844,

74 ; Kiitzing, Sp. Alg. 49.

"~NOPS,
torift.

RHINOPS, Hudson.— A genus of Rota-

BIBL. Hudson, Ann. Nat. Hist. January
1869.

RHINOT'RTCHUM, Oorda.— A genus of
Mucedines (Hyphomycetous Fungi), cha-
racterized by more or less clavate threads
studded with spicules, to which the spores
are attached, Several species occur in this
country. A very beautiful rose-coloured
species has lately been gathered in rabbits'
dung.

Nematozonum, Desm., differs in bearing
necklaces of spores.

BIBL. Berk. Outl 348; Cooke, Handb.
590.

RHIPIDODEN'DRON, Stein.— A genus
of Flagellate Infusoria. Bodies ovate, con-
tained in elongated parallel, granular tubes,
forming a branched zoary. Two species;
freshwater. (Kent, Inf. 285.)

RHIPIDOPH'ORA, Kiitz.— A genus of
Diatornacese.

Char. Those of Licmophora, except that
the frustules are each furnished with a

distinct stipes ; but as this is not always the
case, the character is of little or no value.
Marine.

Three British species (Smith) ; twelve
others (Kutzing).

R. paradoxa (PI. 17. fig. 19). Stipes fili-
form, dichotomous ; frustules in front view
broadly wedge-shaped, somewhat acute at
the base. Length of frustules 1-540 to
4-480".

RHIZAMTSIINA, Brady.— A thread-like
Foraminifer, or chitino-arenaceous branch-
ing tube (1-50" diam.), forming a tangled
weed-like tuft. H. algaformis, from 2160
fathoms near Juan Fernandez. (Brady, Jn.
M. Soc. n. a. xix. 39.)

RHIZID'IUM, Braun.— A genus of Uni-
cellular Algae, allied to Chytridium. At
first unicellular, then bicellular, and with
delicate multipartite rootlets ; cells oblong ;
fructiferous cells beneath the apex ; zoo-
spores with a cilium. Parasitic in Euglence
and NiidlcB.

BIBL. Braun, Monatab. 1856, 591; Ra-
benht. Alg. iii. 284.

RHIZ'INA, Fr.— A genus of Helvelloidei
(Ascomycetous Fungi), distinguished from
Peziza by the bullate hymenium, con-
cave beneath, and furnished with rooting
fibrils.

Two species have been found in this
country, on sandy banks where the heath
has been burnt.

BIBL. Fr. Syst. Myc. ii. 33 ; Currev, Linn.
Tr. xxiv. 493 ; Cooke, Handb. 664.

RHIZOCLOTsTIUM, Kiitz.— A genus of
Confervaceae (Confervoid Algae), distin-
guished by the decumbent habit and the
short, root-like appendages to the branches.

Kutzing includes here many of our British
Confervas :

R. rivularc, C. Filaments simple, diam.
1-900", fine bright-green bundles 2 to 3 feet
long ; in streams and rivers ; common (Dill-
wyn, pi. 39).

R. tortuosum, Dillw. Filaments simple,
diam. 1-800", rigid, curled and twisted,
forming large strata; in salt-water pools;
abundant (Dillwyn, pi. 46).

R. arenosum, Carm. Filaments simple.
diam. 1-1000 to 1-1800"; in dirty-green
strata ; sandy sea-shores.

R. obtusangulum, Lyngb. (PI. 9. fig. 12).
Filaments branched, diam. 1-1400"; pale-
green, stratified ; sandy sea-shores.

R. riparium (Jergensii, Kiitz.). Fila-
ments branched, diam. 1-1400 to 1-1800".
Apparently not distinct from the preceding.

RHIZOGLYPHUS.

[ 657 ]

RHIZOSELENIA.

On sandy sea-shores ; not uncommon (Engl.
Botany, pi. 2100).

It. impkxum, Dillw. Filaments simple,
diam. 1-2000"; bright green; forming large
strata, on mountain-rocks (Dill. C. im-
plex a, tab. B).

R. arenicolum, Berk. (Kochianum, Kz.).
Filament 1-2000 to 1-2400"; mountain-
rocks (Berkeley, Gleanings, pi. 13. fig. 3).

BIBL. Harvey, Mar. Alg. 206, pi. 24 F ;
Kiitz. Sp. Alg. 385 ; Tab. Phyc. ; JBr. Fl. ii.
pt. 1.354; Dillwyn,.Z?r. Conferva; Rabenht.
Alg. iii. 329.

RHIZOG'LYPHUS. See ACARUS, p. 5.

RIIIZOMOR'PHA.— The name given by
authors to certain mycelioid expansions with
a dark bark, which have been traced to
Polypori and Sphceriacei. Many of the
forms which occur in mines are remarkable
for their luminosity.

BIBL. Berk. Int. Crypt. Sot. p. 266.

RHIZONE'MA, Thw.— A genus of Oscil-
latoriaceae (Confervoid Algae) = Dictyonema,
Kiitz. This curious plant (It. inter ruptum)
differs from its allies by the gelatinous
sheath being composed of distinct cells and
furnished with branched root-like processes,
which anastomose freely. The cell-contents
are deep blue-green, with occasional yel-
lowish interstitial cells.

BIBL. Thwaites, Eng.Bot. Supp. pi. 2954;
Kiitz. Sp. Alg. 321; Tab. Phyc. ii. pi. 40. f. 5.

RHIZOPHOR A'CE^E.— A family of Di-
cotyledonous plants, to which belong the
celebrated Mangrove-trees of the tropics.
They are remarkable for the general occur-
rence of a ramified form of liber-cell (PI. 48.
fig. 31). The long woody radicles pushed
out by the fruits, while still attached to the
parent tree, contain a vast number of these
ramified cells with very thick walls.

RHIZOPHYD'IUM, Schenk, = Chytri-
dium, sp.

RHIZOP'ODA, Duj., or better, Psettdo-
poda, Ehr. — A Class of the animal subking-
dom Protozoa.

Char. Gelatinous, structureless aquatic
animals, mostly minute, locomotive organs
consisting of variable retractile root-like
processes — pseudopodia or false legs ; no
mouth.

The food-particles are drawn into the
body by the pseudopodia, as described under
Actinophrys. The body is sometimes naked,
at others enclosed in a carapace or external
skeleton, which is either chitinous, calca-
reous, or siliceous. A nucleus and a con-
tractile vesicle are sometimes present, some-

times absent. In some, the protoplasm
contains granules and yellow cells; these
have been supposed to be parasitic orga-
nisms, a rudimentary form of liver, .or re-
productive organs. The presence of the
contractile vesicle in some Rhizopoda, and
its absence in others, is entirely opposed to
the view of Stein and Kent, that the
presence of a contractile vesicle is a cha-
racter of anirnality; unless many of the
Rhizopoda be referred to the Vegetable
Kingdom. The Class is divided into four
Orders, thus : —

RETICTJLARIA. Pseudopodia slender,
anastomosing to form meshes. — Foramini-
fera, Lieberkiihnia, Labyrinthula, &c.

RADIOLABIA. Pseudopodia radiating. —
Actinophryina, Acanthometra, Polycystina,
Thalassicolla.

LOBOSA. Pseudopodia short, variable,
not anastomosing. — Amoebaea, Arcellina.

GBEGABINIDA. Pseudopodia absent ;
these are often considered a distinct Class
of Protozoa.

BIBL. Dujardin, Ann. Sc. Nat. i., iii.,iv. ;
Schultze, PolythaL, 1834; Carpenter, Phil.
Tr. 1856, 1859, 1862 ; Huxley, Invertefoata;
Williamson, Tr. Mic. Soc. 1852, 169, and ii.
159 ; Reichert, Ann. N. H. x. 1862, 401 ;
Kclliker, Zeitschr. wiss. Zool. 1849; Lie-
berkiihn, ibid. 1856, 308 ; Carter, Rhizopoda
ofEng. 8f India, Ann. N. H. 1865 ; Tr. Mic.'
Soc. 1849, 174 ; Miiller, Mull. Archiv, 1858 ;
Focke, Physiol. Stud. 1854; Fresenius, Beitr.
z. mikr. Organ. 224; Miiller, Monatsb. Akad-
Berlin, 1856 ; Bailey, Americ. Journ. Sci. xv.;
Claparede & Lachmann, Infus.; Haeckel,
Radiolarien, 1862; Gener. Morphol. ; Archer,
Qu. M. Jn. 1870-78; Hertwig & Lesser,
Arch. mik. An. 1874, x. Suppl.; Schultze,
ibid, x., xi., xiii. ; Hertwig, Radiol. (Histol.)
1876; Wallich, M. M. Jn. xiii. 210; Ann.
N.H. 1877, xix. 158 ; Claus,Zoo%wj; Leidy,
Freshw. Ehiz. N. Amer. 1879 ; Jn. Mic. Soc.
1880, 288; Butschli, Bronn's Klass. $c.
1880 (# the Bibl. therein}-, Cienkowski,
Schnitzels Archiv, 1876, xii. (new genera) :
Pascoe, Zool. 1880, 6.

RHIZOPO'GON, Fries.— A genus of
Hypogaei (Gasteromycetous Fungi). R. ru-
bescens is found in sandy ground. (PL 27.
fig. 8, sporophores).

RHIZOSELE'NIA, Ehr.— A doubtful
genus of Diatomaceae.

Char. Frustules elongate, subcylindrical,

marked with transverse or spiral lines, ends

oblique or conical, and with one or more

long terminal bristles; marine and fossil.

2u

RHODOMELA.

[ 658 ]

RHOICOSPHENIA.

Four British species : R. styliformis, JR.
imbricata, R. setigera, and R. alata.

R. alata (PI. 51. fig. 25). R. americana
(PI. r,o. fig. 46).

The British species were obtained from
Sal pa, Ascidia, and Noctiluca.

BIBL. Ehr. Abh. Berl Ak. 1841, 291 ;
Kiitz. Sp. Ala. 24; Brightwell, Micr. Jn.
1858, 94.

RHODOM'ELA, Ag.— A genus of Rho-
domelaceae (Florideous Algae), containing
two tolerably common British species, with
feathery, inarticulate, branched fronds, the
branches composed of concentric layers of
oblong, colourless cells, with a cortical layer
of minute coloured cells. Colour of R. lyco-
podioides purplish brown, becoming black ; !
height 4 to 18". Colour of R. subfasca \
brownish or reddish ; height 4 to 10". The
ceramidia are stalked on the rainuli, occur-
ring in summer ; the stichidia, with tetra-
hedral tetraspores, occur in a similar situa-
tion in winter ; the antheridia (observed in
R. subfusca) also occur in tufts in the same
position.

BIBL. Harvey, Mar. Alg. 78; Tulasne,
Ann. Sc. Nat. 4. iii. 20.

RHODOMELA'CEvE.— A family of Flo-
rideous Algae. Red or brown sea-weeds,
with a leafy or filiform, areolated or articu-
lated frond, composed of polygonal cells.
Fructification: 1. Conceptacles (ceramidia)
external, ovate or urn-shaped, furnished
with a terminal pore, and containing a tuft
of pear-shaped spores ; 2. antheridia, borne
in tufts in similar situations ; 3. tetraspores
immersed in distorted raniuli or in lanceo-
late receptacles (stichidia), usually in rows.

Synopsis of the British Genera.

Odonthalia. Frolid flattened, linear, with
an obsolete midrib, piunatifid, alternately
inciso-dentate.

Rhodomela. frond cylindrical, inarti-
culate, opaque. Tetraspores contained in
pod-like receptacles (stichidia).

Bostrychia. Frond cylindrical, inarticu-
late, dotted; the surface-cells quadrate.
Tetraspores in terminal pods.

Rhytiphlcea. Frond cylindrical, inarti-
culate, transversely striate. Tetrasjcores in
pod-like receptacles.

Polysiphoma. Frond cylindrical, articu-
lated wholly or in part ; the branches longi-
tudinally streaked. Tetraspores in distorted
ramuli.

Dasya. Frond cvlindrical, the stem inar-
ticulate ; the ramuli articulated, composed

of a single string of cells. Tetraspores in
pod-like receptacles (stichidia'), borne by
the ramuli.

RHODOSPOR'E^. See ALGJE.

RHODYME'NIA, Grev.— A genus of
Rhodymeniaceae (Florideous Atoae), con-
taining seven British species, beautiful,
brightly-coloured sea-weeds, growing on
rocks or larger Algae, having a flat mem-
branous or somewhat leathery frond, ribless
and veinless, of parenchymatous texture.
(R. Palmetta, PL 4. fig. 8.) Most are not
more than 2" high, but R. laciniata and
palmata grow to 10" and 18". The colour
is mostly rose- or blood-red. The coccidia
are formed on the lacerated margins or the
tips of lobes of the frond. The tetraspores
form cloudy spots along the margin, or are
scattered, tetrahedrally divided. The an-
theridia likewise form patches on the sur-
face of the frond, in R. Palmetta a,n& palmata.

BIBL. Harvey, Mar. Ala. 124, pi. 16 A ;
Thuret, Ann. Sc. Nat. 4. iii. p. 19, pi. 3.

RHODYMENIA'CE^E.— A family of
Florideous Algae. Purplish or blood-red
sea-weeds, with an expanded or filiform
inarticulate frond, composed of polygonal
cells; occasionally traversed by a fibrous
axis. Superficial cells minute, irregularly
packed, or rarely arranged in filamentous
series. Fructification : 1 . Conceptacles (coc-
cidia), external or half-immersed, globose or
hemispherical, imperforate, containing be-
neath a thick envelope a mass of spores
affixed to a central column ; 2. antheridia,
collected in flat patches or sori ; 3. tetra-
spores, either dispersed through the whole
frond, or collected in indefinite cloudy
patches. British Genera :

* Frond flat, expanded, leaf -like, dichoto-
nious or palmate.

Stenogramme. Conceptacles linear, rib-
like.

Rhodymenia. Conceptacles hemispherical,
scattered.

** Frond compressed or terete, linear or
filiform, much branched.

tipharococcus. Frond linear, compressed,
two-edged, distichously branched, with an
obscure midrib.

Oracilaria. Frond filiform, compressed,
or flat, irregularly branched ; the central
cells very large.

Hypnea. Frond filiform, irregularly
branched, traversed by a fibro-cellular axis.

RII01COSPHE'NiA,Grunow.— A genus
of Diatoniaceae, = arcuate Gomphonema with

RHOIKONEIS.

[ 059 ]

RICCIA.

a central nodule in tlie curved side. R. cur-
vata (PI. 52. fig. 19).

BIBL. Rabenht. Alg. i. 112.

RHOIKONE'IS, Grun.— A subgenus of
Achnanthidium, comprising two species,
found in the North Pacific.

BIBL. Rabenht. Alg. i. 109.

RHOPALOMY'CES,Corda.— Agenus of
Mucedines (Hyphomycetous Fungi), nearly
allied to ASPERGILLUS, but having the

Fig. 618.

3

Fig. 619.

Khopalomyces nigra.
Fig. 618. Tufts on wood. Nat. size.
Fig. 619. Fertile filaments. Magnified 200 diameters.

spores single (fig. 619), and not in monili-
form series. The single spores are borne
on minute spines (fig. 619, left-hand head).
Thev are mildews growing over decayed
wood, matting, dung, &c. Two new British
species are described by Berkeley and
Broome, found growing together.

BIBL. Berk, and Broome, Ann. N. H. 2.
vii. 96, pi. 5.

RHOPALOSPPHUM, Koch.— A genus
of Aphidse. Six species, on the currant and
gooseberry, Sonchtis, Alisma, Ligustrum,
and Herberts. (Buckton, Aphidce } Ray Soc.
ii. 9.)

RHUBARB.— Garden rhubarb (Rheum
undulatum, and other species) affords, in the
large edible petioles, excellent specimens of
SpiRAL-fibrous STRUCTURES, spiral, an-
nular, and reticulate vessels and ducts : these
are readily isolated by the help of a needle
from a fragment of cooked rhubarb placed
in water on a slide, and are well seen by
polarized light. The petioles and leaves
likewise contain bundles of acicular RA-
PHIDES. The roots also contain
receptacles for a characteristic secretion.

RHYNCHLE'TA, Zenker.— A genus of
Acinetina. Body ovate, free or attached,
with a long anterior suctorial tentacle. R.
cyclopum, freshwater, on Cyclops. (Kent,
Inf. 806,)

RHYNCHOL'OPHUS, Duges, = Enj-
thrcws, Latrreille (not Duges). A genus _ of
Arachnida, of the order Acarina, and family
Trombidina.

Char. Palpi large, free ; labium penicil-
late ; mandibles ensiform, very long ; body
entire; coxas very remote, legs palp-like, i. e.
dilated at the end, posterior very long.

Species numerous ; found in woods, under
leaves, and in mosses.

R. cwereus (PL 6. fig. 40 : a, labium with
palp; b, tarsus; c, plume of labium more
magnified ; d} mandible).

BIBL. Duges, Ann. So. Nat. 2. i. 30;
Gervais, Walckenaer's Arachnid, iii. 175 ;
Koch, Deutschl. Crust. ; Murray, Econ. Enl.
124.

RHYNCHONE'MA, Ktz.— A genus of
ZYGNEMACE^E (which see).

BIBL ; Rabenht. Alg. iii. 229.

RHYNCHOP'AGON, Werneck (Rota-
toii&)=Diglena with a bilobed rostrum!
Two species. (Werneck. Ber. Berl. Ak.
1841, 377.)

RHYNCHOP'ORA, = Lepralia pt. R.

"^^STOHOPBION. See PULEX.

RHYTIS'MA, Fries.— A genus of Phaci-
diacei (Asconiycetous Fungi), growing upon
the leaves of trees and shrubs, forming dark
patches or spots on the surface, breaking
through the epidermis with little scales or
irregular fissures. R. acerinum is exceed-
ingly common, forming large black spots on
the leaves of the sycamore and maple ; the
thecasporous fruit is perfected (on the dead
fallen leaves) in spring ; MELASMIA acei'ina,
which occurs in autumn, appears to be a
preparatory form of this plant. R. salici-
num is common on willow-leaves.

BIBL. Berk. Br. Fl. ii. pt. 2. 290 ; Grev.
Crypt. Fl. pi. 118; Fries, Sum. Veg. 370;
Tulasne, Compt. Rendus, 1852 (Ann. N. H.
2. viii. 118) ; Cornu, Compt. Rend. 1878,
Grevillea, vii. 100.

RICASO'LIA.— A genus of Phyllodei
(Lichenaceous Lichens).

Char. Thallus lobate or laciniate, affixed
by fasciculate rhizinse ; gonidia small, yellow-
green ; spores 1-3-septate. (Leighton, Brit.
Lich. Flora, 112.)

RICCIA, L.— A genus of Riccieee (Hepa-
ticae), consisting of minute green thalloid
productions growing upon damp ground or
floating on water, distinguished from the
allied forms by the capsules being immersed
in the substance of the frond, destitute of
perichsete and perigone, while the archegone
2u2

RICC1A.

[ 660 ]

RIMULINA.

permanently encloses the sporange as an
adherent epigone, bearing a persistent style-
like neck (figs. 621, 622). The antheridia

Fig. 620.

Eiccia fluitans.

Lower surface of a fragment of the frond, with three
imbedded sporanges projecting, their orifices being on
the upper surface.

Magnified 5 diameters.

are globose sacs contained in special cavities,
the orifices of which, narrowed into a neck,
project as short processes from the surface
(cuspides). The epigone being adherent to
the sporange, the spores appear to lie im-
mediately in the cavity of the former when

Fig. 621.

Fig. 622.

Eiccia fluitans.

Fig. 621. Vertical section through the frond and spo-
range contained in its substance.

Fig. 622. Sporange, with persistent epigone, extracted
from the frond.

Magnified 25 diameters.

ripe ; they are unaccompanied by elaters, and
escape by irregular rupture of the epigone.
Several species occur in Britain.

* Terrestrial.

It. glauca, L. Frond without membran-
ous scales below, fleshy, ovate-oblong, two-
to three-lobed, 1-2 to 1" in diameter, the
divisions dichotomous, growing in orbicular
tufts, surface smoothish, punctate, glaucous
green. On banks.

jR. crystallina, L. Differing from the
last chiefly in larger size and lighter colour,
and having large cavernous air-cells opening
widely on the upper surface. Damp mould.

** Aquatic.
R.Jluitans, L. (fig. 620). Fronds with-

out scales below, 1-2 to 2" long, repeatedly
forked, segments linear, notched at the
ends ; when placed on damp earth it pro-
duces radical hairs, (fig. 621-2). Stagnant
water.

-R. natans, L. Fronds with long reticu-
lated scales below, obcordate, 1-2" long, or
with the two lobes again divided; scales
of the lower surface purple. On stagnant
pools.

BIBL. Hook. Br. Fl. ii. pt. 1. 102 ; Bis-
cholf, Nova A.cta, xvii. 909 ; Lindenberg,
ibid, xviii. 361 ; Hofmeister, Vergl. Unters.
43 ; Kny, Jahrb. wiss. Bot. v. : Tr. Mic. Soc.
1880, iii. 125.

RICCIE'^E.— A tribe of Liverworts or
Hepaticae, consisting of delicate, green,
membranous fronds, spreading on the ground
or floating on water. The fruits are always
sessile on the frond, more or less imbedded
in its substance according to the thickness ;
the spores are unaccompanied by elaters.

Synopsis of British Genera.

Spharocarpus. Archegones dorsal, on a
lobed membranous frond, sparingly aggre-
gated. Perichsete obtuse! v conical or pear-
shaped ; perforated at the summit, con-
tinuous with the frond. Perigone wanting.
Epigone crowned by the deciduous style.
Sporange at length free, indehiscent.

Riccia. Archegones immersed in the
frond, scattered, neither emergent nor ex-
posed on the surface until burst. Perichsete
and perigone undistinguishable. Epigone
crowned by the enlarged, long, persistent
style, adherent to the sporange. Sporange
bursting irregularly.

RICE. — This grain is produced by the
grass called Oryza sativa. The seed is
remarkable for the hard character of the
albumen, which is explained at once when
we examine a section under the microscope
(PI. 46. figs. 12 & 13). The ceUs are filled
with very small starch-grains, which are
packed so closely that they assume a paren-
chymatous form and present the appearance
of a continuous tissue (as in maize). The
cohesion of the starch-granules is the cause
of the peculiar grittiness of rice-flour. See
STARCH.

RIMULA'RIA, Nyl.— A genus of Leci-
deinei (Lichenaceous Lichens).

Char. Apothecfa black, rounded, de-
pressed in the centre, dehiscing by a sub-
radiate fissure ; spores simple. (Leighton,
Lick. Flora, 438.)

RIMULl'NA, D'Orb. — A Nodosarine

RIND.

[ 661 ]

ROCKS.

Foraminifer, with, oblique chambers, and a
long slit-like orifice on the edge of the last
chamber. Adriatic. (Parker, J. & B.,
Ann. N. H. 3. xvi. 15.)

RIND.— This word is used to denote a
structure intermediate between epidermis
and bark, — a compound structure consisting
of several, or many layers of cells and even
of distinct forms of tissue, but not present-
ing the characteristic kinds and arrange-
ment which occur in true BARK.

RIVULA'RIA, Roth.— A genus of Oscil-
latoriaceae (Confervoid Algae), subdivided
by Kiitzing, and restricted to the forms in
which there is a distinct manubrium or
elongated cell next to the globular basal
cell. As thus defined, it contains only a
few aquatic species, the rest being trans-
ferred to PHYSACTIS, EUACTIS and allied
genera.

R. angulosa, Roth. Frond floating, glo-
bose, dirty-green ; manubria oblong and
curved, or oblong-ovate and abbreviated ;
filaments torulose at the base, interruptedly
articulated at the apex. Eng. Sot. 968.

R. Boryana, Kg. (PL 6. fig. 18). Frond
globose, greenish brown ; the size of a
cherry ; manubria large ; sheaths yentricose,
colourless, with plaited constrictions; fila-
ments moniliform or interruptedly articu-
late, flagelliforin. fi.jlaccida, smaller, fila-
ments flaccid, not interrupted. Doubtful
species : It, lotryoides, and It. plana.

R. pKcatttj Harv. Frond densely grega-
rious, compresso-plicate, often hollow and
ruptured, dark green : filaments spuriously
dichotomous, attenuated.

BIBL. Kutzing, Sp. Alg. 336 ; Tab. Phyc.
ii. pis. 67, 68 j Harvey, Br. Alg. 1 ed. 150;
Hassall, Ala. 262, pi. 64 ; Eng. Bot. Supp.
pL 2911.

ROBERTI'NA, D'Orb.— A modification
of the Bulirnine form of Foraminifera with
long oblique chambers, 7-10 in the last
whorl, and interdigitating : orifice comma-
shaped. Recent and fossil.

BIBL. Carpenter, For. 196; Parker and
Jones, Phil. Tr. civ. 375.

ROBERTSO'NIA, Br. — A genus of
Copepodous Entomostraca. R. tennis, in
dredgings. (Brady, Copepod., Ray Soc. ii.
25.)

ROBULI'NA, D'Orb.— A common form
of Cristellaritt) in which the orifice is trian-
gular.

BIBL. Williamson, Rec. For. 24 (Cris-
fellan'a} ; Parker and Jones, Ann. JV, H. 2.
xix. 289.

ROCCEL'LA, Ach. — A genus of Rama-
lodei (Lichenaceous Lichens)), growing on
marine rocks, remarkable as furnishing the
dye called orchil or archil. R. tinctoria,
phycopsis, and fwsiformis, the British spe-
cies, grow only in the extreme south of
England.

BIBL. Hook. Br. Fl. ii. pt. 1. 225; Engl.
Bot. pis. 211, 728; Leighton, Lick. Pi.

ROCKS.— Rocks are roughly divided,
according to their origin, into an eruptive
and a sedimentary series. Again, the erup-
tive rocks may be classed in two great
groups, the vitreous and the crystalline ;
the former being in great part structureless,
while the latter consist essentially of cry-
stals. A microscopic examination of the
vitreous rocks, such as Obsidian, pitchstone,
pearlite &c., shows, however, that rocks of
this class are not wholly devoid of structure,
since they almost invariably contain large
numbers of minute crystals (microliths) too
small to be referred with certainty to
any known mineral species, together with
more or less sparsely disseminated crystals
of larger size. The microliths, moreover,
are frequently disposed in approximately
parallel and often tortuous bands ; while
sometimes, bands of structureless matter,
glass of a slightly different colour and den-
sity, are seen to traverse the rock. These
bands, as shown in PI. 42. fig. 8, whether
consisting only of glass, or whether repre-
sented by lines of microliths, are very cha-
racteristic of lava-streams, and are indica-
tive of their fusion and flow. Such struc-
tures are not always apparent to the naked
eye ; and in these cases the microscope often
serves to demonstrate the conditions under
which certain rocks have been formed.

In the examination of the crystalline
rocks, which are essentially built up of
crystals, frequently of different minerals,
and pertaining to various crystallographic
systems, it becomes necessary to determine
their optical characters; and for this pur-
pose the employment of polarized light
affords the best means of discriminating be-
tween them; since, in thin sections of
fine-grained rocks, the application of re-
agents to any particular crystal or grain is
a matter of some difficulty. Before enter-
ing, however, upon the subject of the cry-
stalline rocks, it may be well to take a
glance at a few of the most characteristic
features presented by the vitreous series.

In the Obsidians, pitchstones, pearlites

ROCKS.

[ 662 ]

ROCKS.

and tachylytes, microliths and other minute |
structures are almost always present. Some
of these are mere opaque hairs or threads,
called trichites, strangely bent and twisted
(PI. 42. fig. 3), and concerning whose
mineralogical character nothing definite is
known. Others are fine needles, sometimes
with lateral growths, which, as in the
pitchstone of Corriegills in Airan (PI. 42.
fig. 5), resemble, when highly magnified,
the fronds of ferns. These spicular bodies
or belonites have been referred to augite.
In many of the obsidians and pearlites, the
microliths are minute elongated prisms or
cylinders, and their ends often appear to
be rounded. They commonly form dense
streams, their longest axes lying in approxi-
mately uniform directions, except where
larger crystals occur; and at these points
the streams are deflected and appear to
sweep round the obstacles. In some of the
obsidians and vitreous basalt-lavas, the cry-
stallites exhibit a more or less complex
structure, as in PI. 42. fig. 4, the relation
of which can occasionally be traced to per-
fectly developed crystals. In the pearlites
and in some other glassy rocks, curious
little cracks occur, which separate the rock
into, minute spheroids (PI. 42. fig. 7).
The cracks are seldom continuous all round
the form, but thin away in a very cha-
racteristic manner. There is no nucleus,
and the phenomenon appears to be solely
due to shrinkage upon cooling. The streams
of microliths which often traverse these
rocks, pass without interruption through
this pearlitic structure.

Spherules are sometimes plentifully deve-
loped in vitreous rocks, and result in many
cases from crystallization around a point or
along a line (axiolites) of limited extent.
PL 42. fig. 6 shows parts of two spherules,
in an obsidian from the Lipari Isles, which
have partially coalesced ; and in some speci-
mens they may be found united in coo-
tinuous'strings.

In the felspars and other minerals occur-
ring in certain lavas, enclosures of vitreous
matter are sometimes visible. These are
small portions of the glassy magma which
have been entrapped by the crystals during
their formation. PI. 42. fig. 2* shows glass
lacunae of this kind enclosed within a fel-
spar crystal in one of the lavas of Etna,

The crystalline eruptive rocks consist, p.s
already stated, of crystals or crystalline
grains of various minerals, and it is neces-
sary to study their optical characters in

order to determine them with any preci-
sion. Before entering, however, upon this
method of investigation the student should
become familiar with ordinary hand speci-
mens of the chief rock-forming minerals,
and should acquire some knowledge of the
simple tests, both physical and chemical,
which distinguish the different species. In
the absence of such elementary knowledge,
deductions based solely upon microscopic
observations are sure to be untrustworthy,
if not worthless. The text-books from
which this rudimentary instruction may be
derived are too numerous to need mention.
For the study of the optical properties of
minerals the student may advantageously
consult the works of Dana, Zirkel, Rosen-
busch, von Lasaulx, Fouque", Le"vy, and
other recent contributors to microscopic
petrography.

In a mere sketch of the subject, such as
this must necessarily be, it is impossible to
do more than allude to the microscopic
characters of a few of the most typical
rocks ; and in doing so, we may begin with
a thin slice of granite (PI. 42. fig. 9). The
student doubtless knows beforehand that
he is dealing with a rock composed essen-
tially, of felspar, mica, and quartz. But
there may be more than one species of fel-
spar present, and the mica may also be of
various kinds. To determine the character
of the felspars, he must study their angles
of extinction between accurately crossed
NicoPs prisms j and to do this, it is neces-
sary to employ a microscope with a pro-
perly divided, rotating stage, which can be
centred correctly for any object-glass which
may be used, so that a minute speck in the
preparation can be made to revolve imme-
diately beneath the point of intersection of
two crossed spider-lines set within the eye-
piece. He can, in most cases, ascertain
whether the felspars crystallize in the
monoclinic or in the triclinic system by ob-
serving the character of the twinning in
polarized light. The monoclinic felspars
are usually twinned on what is known as
the Carlsbad type, and show only two dif-
ferently coloured halves or lamellae ; while
the triclinic felspars are striated by nume-
rous twin-lamellse, which polarize in dif-
ferent alternatiug colours; unless, of course,
in either case, the plane of section coincides
with the plane of composition of the twin-
lamellae, i. e. the direction in which the
plates appear to be stuck together. In the
monoclinic felspars, the maximum extinc-

ROOKS.

[ 003 ]

ROCKS.

tion between crossed Nicols either coincides
with the edge formed by the union of the
basal plane and the clinopinakoid, or else
lies at right angles to this edge; while
in the trichnic system the maximum extinc-
tion does not coincide with, or stand
at right angles to the homologous edge ,
formed by the basal plane and the brachy-
pinakoid, but occurs in some azimuth on
one or the other side of those directions,
the angle being determined by rotating the
sta^e upon which the preparation lies. To
facilitate the recognition of the precise
azimuth in which the axes of elasticity lie,
an axially-cut plate of quartz, having a
thickness of 1-6", is inserted between the
object-glass and the analyzer, and the
Nicols should be so adjusted that a uni-
formly violet light pervades the field. A
known crystallographic edge being made to
coincide with one of the spider-lines, the
section is then turned, until a tint is esta-
blished which exactly corresponds with the
tint visible in the field of the microscope
when the preparation is removed. Similar
determinations may also be effected by
stauroscopic methods, which are described
in the works already cited. These means
of ascertaining the position of the axes of
elasticity, are of course applicable to any
minerals which are translucent when cut in
sufficiently thin slices. Tables of the angles
of extinction in the different minerals will
be found in various works on mineralogy.

Reverting to our section of granite, we
may notice that there is perhaps more than
one kind of mica present. One is probably
of a more or less deep-brown colour, and
the plane of the section may be either
parallel with the basal planes of the cry-
stals, thus affording six-sided forms, or it
may cut through the crystals at some angle
to the basal plane. lii the latter case it
will be found, that by rapidly rotating the
polarizing prism, the analyzer being re-
moved, a marked change of colour or tint
occurs, while, if the mica be colourless,
there will merely be a slight change in the
intensity of the light transmitted under
similar conditions. The brown, or in hand
specimens often black, mica is commonly
Biotite, the colourless mica, Muscovite";
but there are many other species of mica,
and in order to know which species is pre- I
sent, it may be needful to have recourse to j
blowpipe analysis or to an examination of
cleavage plates, or of sections coincident |
with the basal plane, in convergent pola- I

rized light. For this purpose two or more
strongly converging lenses are placed above
the polarizer, and are brought just beneath
the preparation. A wide-angle half- or
quarter-inch object-glass should be used in
conjunction with an eyepiece-fitting with-
out lenses, surmounted by an analyzer ; or
better, the arrangement introduced by
Swift, of University Street, Tottenham
Court Road ; in either case, the Nicols being
accurately crossed. To determine the posi-
tive or negative character of the crystal, a
quarter-undulation plate, or a quartz-wedge,
should be employed; but the manner of
using it and the phenomena observed under
these conditions must be looked for in
books specially devoted to such questions.
Again, in a thin section of granite, the
observer will also notice the presence of
more or less quartz. This will appear
colourless and limpid by ordinary trans-
mitted illumination, but in plane-polarized
light it will exhibit strong colours ; and in
convergent light it will, if of suitable thick-
ness, show a more or less perfect inter-
ference-cross. The rotatory polarization of
quartz cannot be observed in ordinary
microscopic rock-sections, which are far
too thin to permit this phenomenon.

Quartz, when examined under moderately
high powers, is usually seen to contain
lacunas partially or wholly filled with fluid,
which is very commonly, but not always,
water. In the partially filled cavities,
bubbles of course exist, the size of which in
relation to the size of their containing cavi-
ties represents the condensation which the
liquid has undergone since its imprison-
ment. On the application of heat the
bubbles contract. The cavities vary greatly
in form ; those shown in PI. 42. fig. 1 are
unusually large. The bubbles in these lacunse
sometimes exhibit spontaneous motion when
high powers are employed.

PI. 42. fig 10. represents part of a section
of Syenite. In this rock, hornblende is
one of the essential constituents. In one of
the patches of hornblende there figured, the
characteristic cleavages are shown, inter-
secting at an angle of about 125°. These
cleavage-planes rim parallel with the faces
of the oblique rhombic prism. In augite,
the corresponding cleavage-planes intersect
approximately at right angles. Hornblende
may also usually be distinguished from
augite by its dichroism, which becomes
evident when the lower Nicol is rotated, the
analyzer being removed. Augite shows, as

ROCKS.

[ 664 ]

HOCKS.

a rule, no dichroism. Augite is a common
constituent of Basalt and other rocks of a
basic character. Fig. 18 shows a section of
a crystal of augite cut transversely to the
principal axis. In fig. 14 are shown the
very peculiar forms of hornblende, which
occur in some phonolites, and which from
their frayed-out ends can sometimes hardly
be recognized as crystals. In fig. 15 some
more hornblende is shown, occurring in a
diorite ; the character of the twinning in the
triclinic felspar is shown in this drawing.
It is in the nature of the felspar that diorite
differs from syenite. The original syenite
of Pliny, from Syene in Egypt, contains
quartz. Many petrologists, however, now
exclude from syenite those rocks in which
quartz is present. The quartzless syenites
are closely related to minette (PI. 42. fig. 11),
in which magnesian mica takes the place of
hornblende. The crystals of mica constitute
the chief features of the rock. The matrix
in which they lie is a finely crystalline mix-
ture of felspar and mica. In the drawing,
the central crystal of mica is cut trans-
versely to the basal plane: the fine striae
representing the direction of cleavage or the
characteristic platy structure of mica. A
crystal of magnetite is also shown in this
drawing. It is a section through an octo-
hedron. Among the minerals which crys-
tallize in the cubic system, Haiiyne and
Noseau are often met with in volcanic rocks,
In PI. 42. fig. 14 some crystals of Noseau
are shown; like all cubic minerals, they
exert no influence upon polarized light.
Haiivne and Noseau exhibit structural pecu-
liarities when examined under high powers,
which cannot be described or figured in this
short article. Fig. 16 represents a crystal
of Olivine in a Saxon basalt: Olivine is
a common constituent of basalt, and some
modern petrographers exclude from basalt
any rock from which olivine is absent : thus
many of the rocks which in England have
always been regarded as basalts, would
under this new arrangement be classed with
the andesites. Olivine being a rhombic
mineral, has its axes of elasticity coincident
with its crystallographic axes. Fig. 17
represents a section of basalt from the
Giant's Causeway, as seen by polarized
light under an amplification of 77 diameters.
The black patch in this drawing indicates
magnetite or titanif erous iron, both of which
minerals are commonly more or less plen-
tiful constituents of basalt. PI. 42. fig. 15
shows a transverse section of a crystal of

Nepheline partly filled with dusty matter.
Nepheline is sometimes met with in basalts ;
this drawing is made from a phonolite. The
phonolites are rocks which essentially con-
tain nepheline. The green crystals in the
drawing are microliths of hornblende.

The rocks Diabase and Gabbro may be
regarded' as varieties or special conditions
of basalt. The latter rock contains diallage
instead of augite ; but these two mineral
species are now regarded by some mineralo-
gists as identical.

The rocks termed Norite and Hypersthe-
nite, contain the rhombic forms of pyroxene,
hypersthene, and enstatite. Fig. 13 is
drawn from, a section of trachyte and shows
crystals of sanidine and oligoclase,the former
a monoclinic, the latter a triclinic felspar.
In the centre is a crystal of sphene or
titanite, which although not a very common
rock-forming mineral, nevertheless occurs
both in plutonic and volcanic rocks.

We now come to rocks of a different class
to those just described. These are known
as metamorphic ; and they are regarded by
some as the result of the alteration of sedi-
mentary rocks by high temperatures existing
at great depths beneath the surface of the
earth, or by the contact or proximity of
eruptive rocks. Others regard them in
many cases as the result of crystallization
from solution, and not by fusion, set up in
sedimentary rocks subsequent to their depo-
sition. Whatever may have been the pro-
cesses by which they have arrived at their
present condition, we find that they consist
of minerals which, in the main, are identical
with those which are met with in eruptive
rocks : thus, gneiss for example, is identical
with granite so far as its mineralogies! con-
stitution is concerned ; but the crystals and
crystalline grains which compose the rock,
are arranged in more or less definite layers
of different mineral character, an arrange-
ment termed foliation. Mica-schist (PI. 42.
fig. 20) is another example of a metamor-
phic rock, and consists essentially of rudely
alternating layers or films of mica and
quartz. Chlorite-, talc-, schorl-, and horn-
blende-schists are rocks of similar structure,
and contain respectively the minerals which
their names imply, together with quartz,
and at times felspars, garnets, &c., while
staurolite, chiastolite, &c. are met with in
certain argillaceous rocks which have also
been subjected to alteration. Quartzite
again is an altered sandstone, and the bed-
ded halleflintas of Scandinavia (PI. 42.

KOCKS.

[ 665 ]

EOCKS.

fio-. 12) are usually regarded as altered
felspathic sandstones, which are identical in
mineral constitution and structure with
the rocks known as felstone, which consist
of a micro-crystalline admixture of felspar
and quartz, and in which the boundaries of \
the component grains are not always clearly i
defined under the microscope. This hazy j
ill-defined granular structure is spoken of
as a crypto-crystalline one; while there is
also another condition of matter having the
same chemical composition in which merely a
nebulous, granular, or faintly-marked fibrous
structure distinguishes it from vitreous sub-
stances, its optical character being similar
to that of glass. This is known as micro-
felsitic matter.

The four drawings which constitute the
lower row in Plate 42 represent sedimentary
rocks, or those which have resulted from
the disintegration of preexisting land, the
degraded materials having been transported
by rivers and deposited in the sea or in lakes.
Sandstones, shales and slates, and lime-
stones, may be regarded as the principal
types of these sedimentary deposits. PL 42.
fig. 21 represents a section of millstone grit
as seen under polarized light. The rock
consists essentially of fragments of quartz
with some fragments of felspar, bound to-
gether by a f erruginous cement. The frag-
ments have probably resulted from the
disintegration of granitic rocks, the mica,
owing to its form rather than its specific
gravity, having been held longer in suspen-
sion, and transported to greater distances in
the old seas in which these materials were
deposited. PI. 42. fig. 22 represents a piece
of Cambrian slate from the Penrhyn quar-
ries in N. Wales. The appearance is that
presented between crossed Nicols. The
general elongation of the constituent particles
in the direction of cleavage, is the result of
pressure, which is further demonstrated by
the frequent distortion of the fossils met
with in these old deposits. Microliths are
also present which have been developed
subsequently to the deposition of the rock.
Similar microliths in other Palaeozoic slates
have been referred by Kalkowsky to anda-
lusite, a silicate of alumina. PI. 42. fig. 23
shows the small spheroidal grains which
occur in the Great Oolite of Lincolnshire.
They are concentric deposits of carbonate of
lime, which often, as in the largest spheroid
in the figure, have a foraminifer as a
nucleus ; in some cases the accretions have
taken place around a grain of sand. The

interstitial matter in these rocks is usually
crystalline carbonate of lime. PI. 42.
fig. 24 is an example of a crystalline, sac-
charoid limestone, statuary marble. It
consists wholly of crystalline grains of
calcite. The twinning of the separate crys-
tals, parallel to a rhombohedral face, is
represented as it is seen by polarized light.
It is impossible in this article to cite
further examples. Volcanic ejectamenta,
which both in their loose and consolidated
states, offer problems of great interest to the
geologist, must pass unnoticed ; but, before
closing this article, it may be worth while
to make a few remarks on the relative
merits of thick and thin microscopic sections
of rocks. In the first place thick sections
are easier to prepare; but in most cases
they are of little or no use to the student,
since the optical properties of the different
minerals cannot as a rule be properly
studied from such feebly translucent pre-
parations. The rotatory polarization of
quartz can of course only be observed in
thick sections taken at right angles to the
optical axis ; and dichroism, when barely
perceptible in certain thin slices, becomes
well marked in thicker ones; but apart
from these advantages which tliick sections
possess, they have others. A thick un-
. mounted section can be submitted to the
action of chemical reagents, and in many
cases may be subsequently washed, ground
thinner, and finally mounted, while much
useful information may be thus gained.
Little objection can also be raised to thick
sections of vitreous rocks, when they happen
to be very transparent, since the crystals
which they contain may then be studied in
their integrity j whereas in thinner sections
we can merely examine slices of them.
Furthermore, in the preparation of very thin
sections there is always the danger either
of stripping out the larger crystals, or of
ultimately wasting labour by grinding away
the whole of the preparation. Thick sec-
tions are best examined by reflected light,
when many important points are often dis-
cerned, which would never be noticed if
transmitted light only were employed. As
a rule, however, it is scarcely possible to
prepare too thin a section of a rock, nor to
over-estimate the value of the thinnest pre-
parations which can be procured; since a
few finishing touches may often permit the
recognition of structure which would other-
i wise pass unnoticed. Most of the lapi-
I daries in this country spoil their sections

ROCKS.

ROOTS.

through not risking their loss or diminution
of size* by those finishing strokes which
render a preparation useful or worthless.
The best sections I have yet seen are those
prepared by Cuttel, of New Compton Street,
Soho. Good rock-sections may also be pro-
cured on the continent, notably from Voigt
and Hochgesang of Vienna, Marchancl
of Paris, and Fuess of Berlin. Machines
for the preparation of rock-sections are
made by Cotton and Johnson of Grafton
Street, Soho, Fuess of Berlin, and others.
Much may, however, be done simply with a
flat cast-iron plate and emery, while a file and
hone will sufhce for the preparation of some
of the softer rocks. Chapters on this
branch of microscopical work will be found
in 'The Study of Rocks/ and in Beale's
' How &c.' Microscopes suitable for this
branch of study, are made by Watson, of
4 Pall Mall, and Swift, of University Street,
Tottenham Court Road.

The student of petrology should, how-
ever, study the great features presented by
rock-masses, and learn to recognize the
large crystals, with which Nature and the
mineral-dealer can provide him, before he
commits himself to microscopic investi-
gation.

BIBL. Zirkel, Mikr. Beschaff. d. Mine-
ralien und Gesteine, 1873 ; id. Mikr. Zusam-
mensetzung d. Basaltgesteine, 1870; id.
Microscopical Petrography, U. 8. Geolog.
Explor. of the 40th parallel, 1876; Vogel-
sang, Die Krystalliten, 1875 ; Rosenbusch,
Mikroskop. Physiographic, 1877 (coloured
plates), and the Bibl. ; Mohl, Basalte und
Phonolithe Sdchsens, 1873; Poussin and
Renard, Caract. mineral, fyc. des roches Plu-
tonniennes de la Belgique et de VArdenne
Franqaise, 1876 ; Boficky, Petrograph.
Stud. Basaltgesteinen Bohmens, 1874; id.
Phonolithgesteine Bohmens, 1873; id. Me-
laphyrgest. 1876; id. Elemente chem.-mi-
krosk. Mineral- und Gesteinanalyse, 1877 ;
(the last 4 works are in the Archiv d. Na-
turwissenschaftl. Landesdurchforschung v.
Bb'hmen) ; Credner, Petrographische Geologic
(JSlemente d. Geologie, 1876) ; Lasaulx,
Petrographie, 1875 ; Geikie, Carboniferous
Volcanic Rocks of the Basin of the Firth of
Forth, Tr. R. Soc. Ed. 1879 ; Fouqu<§ and
Le"vy, Mineralogie Micrographique, Roches
eruptive s Franq., coloured plates and Bibl.,
1879; Sorby, Anniversary Addresses to Geol.
Soc. Lond., 1878-79; Rutley, The Study
of Rocks, 1879; Geikie, Text-Book, 1882.

Numerous papers on Microscopic Mine-

ralogy and Petrology, by Phillips, Sorby,
Allport, Bonney, Ward, Davis, Daintree,
and others, will be found in the Qu. Jn.
Geol. Soc., others in the Jn. Mic. Soc., Tr.
Roy. Soc. Ed., the R. Irish Academy, the
Roy. Irish Geol. Soc., News Jahrb. f.
Mineral., Zeitsch. d. deutsch. geol. Gesellsch.,
Bull. d. 1. Soc. Mineral, d. France, &c.

RCESTE'LIA, Rebent— A genus of Ure-
dinei (Coniomycetous Fungi), closely re-
lated to ^EcimuM, and presenting similar
spermogonia and perithecia ; the chains of
spores of the Rcestelice, however, present a
peculiarity, — having a sterile joint, forming
an isthmus of variable length, between
each spore : the peridium bursts irregularly ;
or (in R. cancellatd) the teeth cohere more
or less for a time, so as to form a kind of
lattice. This genus includes sEcidium cor-
nutum, laceratum, and cancellatum of older
authors, growing respectively on the leaves
of the mountain-ash, hawthorn, and pear.
See yEciDiuM and UREDINEI.

ROOTS.— The structure of roots presents
important modifications ; but these are less
striking than those in stems. In all cases
they have a fibro- vascular axis enveloped in .
a more or less thick cortical parenchyma,
covered when young by a delicate epidermis
devoid of stomata (epiblema), when old by
an epidermal tissue ol corky nature.

The roots of the vascular Cryptogamia
are all adventitious; and their structure
consists merely of a central fibro-vascular
axis, surrounded by a cellular cortex and an
epidermis provided with root-hairs of a
yellowish colour.

Dicotyledons produce an axial root, which
is a direct prolongation of the stem down-
wards ; ana both this and the adventitious
roots frequently developed on the stem have
the peculiar unlimited fibro-vascular struc-
ture found in the stems of this class, and
may become woody and increase by annual
layers like the ascending axis. The axial
root of Dicotyledons, being a direct con-
tinuation of the stem, displays a circular
group of fibro-vascular bundles as in the
ascending axis ; but these mostly converge
at the point of junction of stern and root
(collar), so that the central axis of the pa-
renchyma, the pith, is usually absent, the
medullary rays remaining as in the stem.
Externally, again, there is a difference, since
the liber-bundles vanish and the cambium-
region passes at once into the cortical pa-
renchyma, here colourless and succulent,
and this is clothed by a less prominent peri-

ROOTS.

[ 667 ]

ROOTS.

derm than the stem. The roots of Dico-
tyledons increase in diameter by annual
layers of wood formed in the fibro-vascular
bundles; these, however, are much less
regular in their arrangement than those of
the stem on account of the tortuous course
of the roots ; hence, while the wood of the
roots is often useful for ornamental purposes,
it is comparatively valueless for carpenters'
uses. The branches of the axial root are
originally growths from the apex of the root
thrown off to the sides as it were, and their
woody axis is derived from a division of
that of the main root. The radical of a
germinating Dicotyledon has its pileorhiza,
and grows, in the same way as that of the
Monocotyledons, by development of cells
just behind the apex. Young roots are
covered by a delicate epidermis; and the
cells of this are abundantly produced into
hairs (fibrillse) in many plants, especially in
those growing on light soils ; these fibrils
are deciduous, the delicate epidermis, which
is always destitute of stomata, being gra-
dually converted into a corky layer. Ad-
ventitious roots are very common in Dico-
tyledons, especially the herbaceous peren-
nial kinds, and they alone can exist on plants
raised from cuttings &c. of stems. The
roots originate much in the same way as
those of the Monocotyledons, appearing first
as cellular cones in the region adjacent to
the cambium-layer, with which the fibro-
vascular structure soon becomes confluent.
They break through the rind with a coleo-
rhiza, and protected by a pileorhiza, just as
in Monocotyledons ; but when once formed,
they appear to branch in the same manner
as the axial root, and not by the formation
of secondary adventitious roots.

The radicle of a monocotyledonous embryo
is never developed ; but if a section is made
of the lower part of the embryo, we find one
or more little conical- bodies imbedded in
the parenchyma ; these are the nascent ad-
ventitious roots, which soon appear exter-
nally, breaking their way through the
superficial tissue. The anatomy may, how-
ever, be more easily studied by tracing the
development of the adventitious roots on
the rhizomes of rushes, flags, and other
plants of this class. The roots originate in
the region where the fibro-vascular bundles
of the stem terminate, (and frequently form
a fibrous plexus). They are first wholly
cellular, and consist of three parts : — a
woody axis which soon becomes continuous
with the Hbro-va.scular plexus; a cortical

parenchyma, continuous with the inner part
of that of the parent stem ; and a kind of
conical hood of rather dense cellular tissue
enveloping the end of the root. As the
root grows it pushes the hood forward,
which breaks down the cellular tissue before
it, and finally appears externally. When
the epidermis is ruptured in this way, it
presents a circular free edge standing up
slightly like a collar around the base cf the
free part of the root : this is called the
coleorhiza by some authors. The conical
hood upon the apex of the root, called the
pileorhiza, is more or less persistent in dif-
ferent cases ; in aquatic plants it becomes
greatly developed, as may be seen in the
duckweed (Lemna)r where it forms a long
sheath, appearing as if slipped over the end
of the rootlet. The focus of development
of the root is within the pileorhiza, which is
pushed forward by the continued develop-
ment of cells just behind the apex. The
pileorhiza may be compared to a kind of
shield or guard to the tip of the root, pro-
tecting the nascent tissue, by the expansion
of which it is pushed forwards, itself always
possessing a certain solidity, which enables
it to penetrate between the particles of the
soil.

The centre of the root of a Monocoty-
ledon is occupied by prosenchymatous tissue
with a circle of vessels around it, the whole
enclosed by regular parenchyma, sometimes
by liber-cells and covered by an epidermis.
The ring of vessels spreads out into a kind
of rosette at the base, and anastomoses with
the extremities of the fibro-vascular bundles
of the stem in the fibrous region. Secon-
dary adventitious roots are formed in the
same way in the roots, originating imme-
diately upon the vascular ring and breaking
through the cortical parenchyma. The
woody adventitious roots of arborescent
Monocotyledons differ only in the greater
development of the fibro-vascular struc-
tures; and they emerge from the stem
(palms) in the form of thick conical shoots.
In the thickened adventitious roots of as-
paragus, which perform the function of
tubers, the parenchyma is greatly developed.
In the tuberous roots of Orchids the central
woody axis becomes irregularly expanded
into parenchymatous tissue, driving the
vessels out nearly to the periphery, so that
the characteristic structure is greatly dis-

SLiised. The aerial roots of the epiphytic
rchids have the growing extremities
clothed by several layers of a parenchy-

ROT ALIA.

[ 668 ]

ROTATION.

matous tissue, in which the cells are cha-
racterized by delicate open spiral-fibrous
secondary layers.

Roots grow by cell-development only near
the apex; and interstitial expansion soon
ceases. Old roots of Dicotyledons present
a dense heart-wood like the trunks, the
passage of fluid taking place through the
outer layers. When the older parts of roots
are exposed to the air by removal of soil,
they acquire a thick corky periderm. The
general structure of the root of Conifers is
like that of Dicotyledons.

BIBL. Henfrey-Masters, Bot. ; Nageli and
Leitgeb, Nag., Wiss. Sot. 1867 ; Hofmeister,
Morphol. d. Geweb. 1865 ; Tieghem, Ann.
Sc. N. 5. xiii.; Sachs, Sot. 165; Olivier,
Rac. Ug. 1882 (50 pis.).

ROTA 'LI A, Lamarck (restricted).— A
typical Foraminifer; shell ammoniform,
neat, finely porous, unequally biconvex ;
with 13-40 chambers, double . septa, and
canal-system ; limbate and often granulate.

Species numerous, both fossil and recent
(R. Beccarii, PI. 24. figs. 13, 14).

BIBL. Carpenter, For. 212; Micr. 546;
Parker & Jones, Phil. Tr. civ. 387.

ROTALI'NA, Carpenter (Rotalina).—
A subfamily of Globigerinida. See FORA-

MINIFEBA.

BIBL. Carpenter, For. 198; Parker &
Jones, Phil. Tr. civ. 378, and Qu. J. G. S.
xxxviii. 103.

ROTATION or C YCLOSIS.— This term
is usually employed in botanical works to
denote peculiar flowing movements of the
contents of vegetable cells ; and it is useful
to retain the word for all cases of the kind,
in order to avoid confusion of these pheno-
mena with the general circulation of the sap.
The term " circulation of the cell- sap " is,
however, often used instead of rotation, and
especially in reference to the cases where it
exnibits numerous distinct currents.

The rotation presents itself in two types,
namely — (1) a rotatory movement of a layer
of protoplasm investing the entire internal
surface of the cell, as in CHARA, &c. ; and
(2) a radiating movement of the protoplasm
in slender currents, from the nucleus out over
the remainder of the cell, with a return flow
towards the nucleus ; but as the nucleus
itself shifts in the latter type as in the
former, the two kinds are scarcely definitely
distinguishable ; they may, however, be
spoken of separately.

The rotation in Char a and NiteUa has
been long known ; a similar movement oc-

curs in many water-plants, such as Vallis-
neria, Hydrocharis, Anacharis, Slratiotes,
Sagittaria, Potamoffeton,Ceratophi/llton, &c.,
where it is seen best in the more delicate
foliaceous structures, such as young leaves,
stipules, or sepals, or in the young rootlets.
It has also been observed in the fruit- stalks
of Slasia pusilla and some other Hepaticse.

In the CHAEACE^E the wall of the cells is
lined with chlorophyll-granules, leaving two
oblique or spiral stri8e bare (fig. 125, p. 162) ;
these striae indicate the boundaries of the
ascending and descending currents (marked
by arrows) . The moving substance is a vis-
cid semifluid layer, lying within the chloro-
phyll-layer, and itself surrounding the
watery cell-sap occupying the centre of the
cell. This layer, forming a kind of gelatinous
sac, moves in a spiral course up one side of
the cell and down the other, the motion
being rendered very evident by chlorophyll-
and other granules imbedded in it ; these
appear to be carried along passively by the
stream, the larger slowly, the smaller with
greater rapidity. In VaUisneria, Anacharis,
&c. the chlorophyll-granules and the nu-
cleus are imbedded in and moved with the
flowing protoplasm. If long cells of Chara
are bent or tied round by a ligature, the
circulation is not stopped, but takes place
independently in each half. If a cell of
Chara is cut across, the protoplasm of the
current flowing towards the cut surface
escapes at once, but that of the current
flowing away, goes on to the end of the
cell, turns round, and then flows towards
and out from the wound.

The size of the stream seems to be in in-
verse proportion to the length of the cell,
decreasing as the latter acquires its full
development. The rapidity of the current
varies according to the age of the plant and
the activity of its vegetation. It is most
rapid in hot weather and in sunshine. Arti-
ficial elevation of temperature in the water
in which the plant grows, up to a certain
point, hastens the movement; a heat above
80* Fahr., however, retards it for a time.
A temperature of 112° Fahr. kills the plant,
as also does a cold of about 20°. Darkness
appears merely to exert effect through its
influence on the activity of the vegetation.
Keeping Chara in water exhausted of air
does not stop the rotation until the plant
dies. Most chemical reagents seem to exert
no special action ; only lime-water appears
to stop it in a few moments. A solution of
sugar, or gum, or milk greatly hastens the

ROTATION.

ROTATORIA.

rotation in Vallisneria, so that the proto-
plasm is moved on in waves ; but the pri-
mordial utricle finally dissolves, and the
movement ceases. Passing an electric cur-
rent through the cell stops the current for
a time ; but it recovers itself, just as occurs
after any mechanical interference. If several
cells are injured by cutting or pricking, the
whole rotation stops in young plants, but it
gradually returns as before in the uninjured
cells. Pressure interrupts or stops the mo-
tion for a time only ; when removed, the
current is gradually restored; but actual
injury to the cell stops it for ever.

The rotation which takes place between
the external surface of the green layer and
the outer cell-membrane in Closterium and
other DESMTDIACE^ appears to be of the
same kind as the above.

The circulation in reticular currents, first
observed by Brown in the hairs of the
stamens of Tradcscantia, appears to exist
far more extensively, if it be not even a uni-
versal phenomenon. It has been observed
in the Confervoideae, Fucoideae, Florideae,
Lichens, Fungi, Hepaticae, Equisetaceae,
Lycopodiaceae, and Ferns, and in the most
varied families of Flowering plants. It is
seen most easily in young tissues, especially
such as can be prepared readily without
much mechanical injury,; for example, in
hairs, cells of the pulp of fruits, cells of the
germen of Onagraceae, of the labellum of
Orchids, &c. It generally exhibits the fol-
lowing characters : — In the middle or at one
side of the cell occurs a large heap of pro-
toplasm, in which is imbedded the nucleus ;
from this protoplasm more or less slender
filaments run out over the cavity of the cell,
and as these contain numerous fine granules,
a flowing movement which takes place be-
comes evident by the change of place of the
granules. Attentive examination shows that
these flow out from the central mass and
return to it, and, moreover, that the cur-
rents change their form and direction, and,
lastly, that the nucleus itself moves. This
rotation cannot be observed in very young
cells when the cavity is densely filled with
protoplasm ; but Hofmeister states that he
has seen the entire primordial utricle rotate
in the special parent cell of the spore of
Phascnm cuspidatum. As the young cells
increase in size, vacuoles are formed in the
protoplasni,filled with watery sap ; and these
enlarging and becoming confluent, leave the
protoplasm in the form of a reticulated
mass.

The cause of the motion is evidently
related to the movements exhibited by free

Srotoplasmic bodies, such as ZOOSPORES,
PERMATOZOIDS, the free filaments of Os-
CILLATOHIA, &c. It has been well com-
pared with the movements of the body of
Amoeba, which bear considerable resem-
blance to some kinds of the reticular rota-
tion. The relation existing here is further
borne out by the fact of pulsating vacuoles
existing in Volvox, Gonium, &c., just like
those in the Infusoria.

The actual rotation or movement in a
definite direction is the result of the con-
fining cell-wall on the contracting and ex-
panding protoplasm. It is produced in
Algae during cell-growth.

The rotation in Chara may be observed
by simply placing portions of the plant on a
slide in water. The unincrusted species are
of course most favourable ; but the growing
points of the others are tolerably transpa-
rent. In Vallisneria, detached fragments of
leaves, or even horizontal sections of the
leaf, may be used; in Anacharis, entire
leaves or sepals may be detached and ob-
served. Hairs are frequently more or less
covered with a viscid secretion, which re-
tains air-bubbles about them ; in such
cases, it is often useful to dip them for an
instant in alcohol, and then place them in
water.

BIBL. Varley, Tr. Soc. Arts, xlviii. ; Mic.
Trans. ; Slack, Tr. Soc. Arts, xlix. ; Du-
trochet, Compt. Rend. 1837, 775 ; Becque-
rel, ibid. 784 ; linger, Sitzungsber. Wien.
Ak. viii. 32 ; Mohl, Sot Zeit. iv. 73 ; Ann.
N. H. xviii. 1 ; Hofmeister, Very. Unters.
73; Osborne, Mic. Jn. iii. 54; Branson,
ibid. iii. 260; Wenham, ibid. iii. 250 ; Hen-
frey, Ann. N. H. 3, i. 419; Reichert, Ann.
N.H. 1867, xix. 10; Beale, How $c. 4th
edit. 165 ; Carpenter, Microscope ; Henfrev-
Masters, Bot. 551.

ROTATO'RIA or ROTIF'ERA. — A
Class of the ANIMAL KINGDOM.

Char. Microscopic, transparent animals,
living in fresh or in salt water ; legs absent ;
anterior portion of the body furnished with
one or more retractile, often lobed disks,
upon which are placed usually vibratile
cilia, when in motion presenting the appear-
ance of one or more revolving wheels ; ali-
mentary canal usually distinct, with a den-
tal apparatus, and two orifices ; reproduction
by ova.

Body covered with a firm and usually
smooth skin or integument, sometimes pre-

ROTATORIA.

[ 670 ]

ROTATORIA.

senting indications of segments ; often more
or less enclosed in a carapace (CARAPACE),
which is either secreted by the skin, by the
alimentary canal, or by a special secreting
organ. In some species the skin is fur-
nished with cilia, hairs, or rigid bristles.

In most, there is a tail-like process at the
posterior end of the body called the foot-
like tail, tail-like foot, or false foot ; this is
jointed, and can often be contracted and
extended like a telescope ; it does not form
a direct prolongation of the end of the body,
but arises from and is situated upon the
ventral aspect. It is often terminated by a
suctorial disk, or a pair of claw- or toe-like
processes.

Distinct longitudinal and circular muscu-
lar bands are present ; and they sometimes
present transverse striae.

The rotatory disks or wheel-organs vary
greatly in structure, the varieties forming
characters of the families and genera.

Their margin is usually furnished with
one or two rows of vibratile cilia ; some-
times these are replaced by bundles of non-
contractile elongate cilia (PI. 43. fig. 32),
or the rotatory organ is divided into ten-
tacle-like processes, upon which cilia are
placed (PL 44. fig. 25).

The rotatory disk is the principal organ
of motion, by means of the cilia of which
the animals swim through the water ; some
of the Rotatoria, however, move in a leech-
like manner, by alternately fixing the toe-
like processes and the anterior end of the
body, which in some forms a kind of pro-
boscis (PI. 43. fig. 1).

The nervous system is not well known.
It appears to consist of a ganglion and of
branches given off in various directions.

In many of the Rotatoria, eyes are pre-
sent, mostly red. These appear to have a
cornea and a lens. They sometimes dis-
appear in the adult animals ; and as their
number, position, &c. are used as charac-
ters, when absent in the adults, they must
be looked for in the young or the ova,
either within tlie carapace or adherent to
the body.

Alimentary apparatus. — Behind the mouth
is sometimes a distinct conical pharynx,
but nearly always a rounded muscular giz-
zard containing the jaws and teeth. In the
pharynx are occasionally seen two undula-
ting lines, presenting a flickering appearance,
the indications of cilia or undulating mem-
branes. The jaws are constructed mostly
-after two forms. In one of these they con-

sist of two knee-shaped pieces (PI. 43. fig.
24), — to the posterior portion of which
muscles are attached, whilst the anterior,
which passes inwards at a right or obtuse
angle to the former, ends in a single point
or in several teeth (fig. 26). In the other,
the jaws have the form of stirrups (fig. 17),
with their bases turned towards each other,
upon which two or more teeth are placed.
A third single or compound intermediate
piece forms a support (figs. 24, 26), upon
which the food acted upon by the jaws
is triturated. In some species the jaws
and teeth are very complex in their ar-
rangement.

The alimentary canal is usually short and
straight, but sometimes curved. Its walls
are very thick, and lined with ciliated epi-
thelium. The stomach forms a distinct
expansion (PI. 43. fig. 27 c) ; this is suc-
ceeded by an intestine, the termination of
which corresponds to a cloaca, receiving the
expelled contents of the reproductive organs
and so-called water- vessel system, and open-
ing at the base of the foot. In some Rota-
toria a second expansion or stomach is situ-
ated below the upper one.

The walls of the stomach and intestines
frequently contain brown or yellow cells,
representing a liver ; and at the commence-
ment of the stomach are two or more caecal
appendages, probably corresponding to a
pancreas (PI. 44. fig. 14).

In the male Rotatoria, the alimentary
canal is entirely absent.

Vascular system. — Distinct bloods
are apparently not present in the Rotatoria ;
but on each side of the body, in most of
them, runs a narrow straight or wavy band,
containing a slender vessel (PI. 43. fig. 18 a;
PI. 44. fig. 14 b). Anteriorly, these vessels
give off branches, the terminations of which
are not well known. By some thev are said
to open into the abdominal cavity, by others
to terminate as caeca. Attached to the walls
of these lateral tubes, or situated within
them, are pear-shaped or oval corpuscles
(PI. 43. fig. 18 a; PL 44. fig. 14 c), which
exhibit a flickering appearance from the
action of cilia connected with them, and
which open into the cavity of the abdomen.
Posteriorly, the tubes terminate in an ac-
tively contractile sac, which opens into the
cloaca. In regard to their function, these
tubes have been variously viewed as water-
vessels, testes, and kidneys. Ehrenberg con-
sidered them j).s connected anteriorly with
a certain projecting organ (PL 44. fig-. 14 a

ROTATORIA.

[ 671 ]

RUCKER1A,

situated usually in the cervical region (PI. I
43. fig. 3 ; PL 44. fig. 17), denominated the i
calcar or respiratory tube, and terminated
by a retractile tuft of non-vibratile cilia
(fig. 5 «). They have no relation, how-
ever, with this, which corresponds to an
antenna. Huxley proved that they are
part of a water-system.

Beneath the integument of the Rotato-
ria, a kind of irregular circulation, varying
with the motions of the body, or a simple
molecular movement of minute granules, has
been noticed. These granules are probably
situated in the abdominal cavity j in which
also sarcodic globules, sometimes free, at
others connected by filaments, have been
observed.

Reproduction.— -The Rotatoria are propa-
gated by means of sexual organs, and are
unisexual. The female organs consist of
one or two longer or shorter ovarian sacs or
ovaries, situated towards the posterior end
of the body in the abdominal cavity, the
oviduct terminating in the cloaca, or at a
distinct vulva. The ova are of an oval
form, and are sometimes smooth externally
and soft. The winter-ova are larger an'd
darker than those hatched during the sum-
mer, and the outer coat is thick and hairy
or tubercular. The winter-ova which re-
main so long attached to the posterior part
of the body are probably gemmse ; they
sometimes remain adherent to the cloaca
for a time, and in a few instances they are
hatched within the ovary.

The testis is situated at the posterior
part of the body, and consists of a wedge-
shaped body, with a muscular duct opening
externally.

Many of the Rotatoria are remarkably
tenacious of life ; and some of them are
stated to have revived after having been
kept dry for several years.

Perfect desiccation destroys the Rotifers,
but they will last a long time with a very
slight amount of moisture.

The families of the Rotatoria are thus
distinguished : —

Ciliated margin of rotatory disk simple or continuous.
Margin entire. Holotrocha.

Carapace absent Ichthydina.

Carapace present CEcistina (?).

Margin undulate or excised. Schizotrocha.

Carapace absent Megalotrochsea.

Carapace present Floscularisea.

Rotatory disk divided or multiple.

Divided into several parts. Polytrocha.

Carapace absent H jdatinaca .

Carapace present Euchlanidota.

Divided into two parts. Zygotrocha.

Carapace absent Philodinaea.

Carapace present Brachionaea.

See ALBERTINA.

They are found wherever water exists,
provided it be not in a state of putrefaction,
— thus in pools, on moist earth, mosses, in
gutters, &c., and even in the cells of mosses
and algae.

BEBL. Ehr. Inf. j Dujard. Inf. ; Siebold,
Vergl An. ; Dalrymple, Phil. Tr. 1849, 331 ;
Huxley, Micr. Trans. 1852, i. 1 ; William-
son, Micr. Jn. i. 1 j Cohn, Siebold und Kol-
liker's Zeitsch. vii. 431 ; Gosse, Tr. Micr.
Soc. iii. ; id. Ann. N. H. 1851, viii. 198
(several new genera and species) j and 1850,
xviii. 333; Pritchard, Inf. ; Schmarda, Neue
Rotatoria, 1861 ; Mecznikow, Sieb. und Koll.
Zts. 1865 ; Qu. Mic. Jn. 1666, 34 & 240 j
Claparede, An. N. H. 1868, i. 309 ; Schloch,
Rdderthiere, 1869 j Cubitt, M. M. Jn. vi.
168, viii. 5 ; Hudson, M. M. Jn. xiii. 45 j
Pascoe, Zool.

ROT'IEER, Guv.— A genus of Rotatoria,
of the family Philodineea.

Char. Eyes two, situated upon the pro-
boscis ; foot furnished with lateral horn-
like processes, and with two terminal toes,
giving its end a bifurcate appearance j fresh-
water,

It. vulyaris (PI. 44. fig. 23). Body fusi-
form, white, gradually attenuated towards
the foot-, length 1-48 to 1-24".

This is one of the commonest of the
Rotatoria, and has long been known as a
favourite microscopic object under the po-
pular name of the wheel-animalcule. The
anterior and upper part of the body termi-
nates in a proboscis, ciliated at the end, and
upon which the eyes are placed ; the two
rounded lobes of the rotatory organ are
placed laterally. Behind, and at the root
of the proboscis, is the calcar.

In R. citrinus, the middle of the body is
yellowish, the horns of the foot long, and
the eyes round. In R. macrurus, the body
is suddenly narrowed into a long foot. In
R. tardus the body is gradually attenuated,
but somewhat deeply constricted into seg-
ments.

BIBL. Ehr. Infus. 484 ; Pritchard, Inf. ;
Grenadier, M. Mic. Jn. 1870, 44.

ROTIF'ERA. See ROTATORIA.

RUBEFAOTION OF WATER. See
WATER.

RUCKE'RIA.— A genus of Composite.
The pericarp possesses HAIRS of an inter-
esting structure.

RUELLIA.

[ 672 ]

SALICORNARIA.

BIBL. Decaisne, Ann. Sc. Nat. 2. xii.
251 ; Ann. N. H. vi. 257.

RUEL'LIA. — A genus of Acanthaceous
plants. The testa of the seed of Ruellia
formosa exhibits a peculiar kind of HAIR
'(PI. 28. tig. 21).

RUST OF PLANTS. See BLIGHT.

RUTILA'RIA, Gr.— A genus of Diato-
macese. Frustules compressed, forming a
short filament ; valves elliptical, elevated at
the angles, with a central no'dule, termina-
ting in two short processes ; margin spinous.
3 species ; in the Barbadoes deposit. (Gre-
ville, Tr. Mic. Soc. 1866, 124.)

RYE. — The grain of Secak cereale. See
STARCH.

RYLAND'SIA, Gr. & Ralfs.— A genus
of Diatomaceae. Frustules simple, disk-
shaped, areolar ; valves with two opposite
smooth rays, dilated at their base, not
reaching the centre. It. biradiata, Barba-
does deposit. (Greville, Qu. Mic. Jn. 1861,
67.)

RYTIPHLCE'A, Ag.— A genus of Rho-
domelacese (Florideous Algae), containing
four British species, mostly common, having
pinnately branched, filiform or compressed
fronds, transversely striate and reticulated ;
the articulate axis is composed of a circle of
large elongated tubular cells surrounding a
central cell, the whole enclosed by a kind
of rind of several layers of small coloured
cells. Colour mostly dull red or brown.
Fronds from 2" to 4" or 6" high. Cera-
midia scattered on the ramules of some
plants ; antheridia tufted in the same situ-
ations on others ; and tetrahedral tetra-
spores occur imbedded in a double row in
stichidia, borne on distinct plants. R. pinas-
troides (PI. 4. fig. 11).

BIBL. Harvey, Mar. Alg. 80 ; Grev. Alg.
Br. ; Derbes and Solier, Ann. Sc. Nat. 3.
xvi. 275 ; Thuret, ibid. 4. iii. 20.

S.

SACCAM'MINA, Sars. See LITUOLIDA.

SACCOG'YNA.— A genus of Junger-
rnanniese (Hepaticae) founded on Junger-
mannia viticulosa of Linnaeus ; it is re-
markable on account of the subterraneous
fleshy perianth, in which character and in
habit it is allied to Calypogeia. It is found
among mosses, especially in alpine districts.

BIBL. Hook. Br. Fl. ii. pt. 1. 121 ; Br.
Jung. pi. 60 ; Ekart, Syn. Jung. pi. 1. fig. 6;
Endlicher, Gen. PI. Supp. 1. No. 472-23.

SAC'CULUS, Gosse.— A genus ofRota-
toria, of the family Ichthydina.

Char. Eye single, frontal j body free from
hairs, and without a foot ; rotatory organ a
simple wreath ; alimentary canal very large ;
jaws set far forward, apparently consisting
of two delicate unequal lateral pieces, and
a slender central portion, very evanescent ;
eggs attached behind after deposition.

8. viridis. Length 1-150" ; freshwater.

BIBL. Gosse, Ann. N. H. 1851, viii. 198.

SADLE'RIA, Kaulf.— A genus of Blech-
neae (Polypodiaceous Ferns) . Two species ;
arborescent; Sandwich Islands. (Hooker,
Syn. Fil. 187.)

SAGENEL'LA, Brady. —A simple,
branching, Arenaceous Foraminifer, at-
tached to Nulli pores, forming a network
with its anastomosing branches (1-200" to
1-65" in diameter). Admiralty Islands.
(Brady, Qu. Jn. Mic. Sci. n. s. xix. 41.)

SAGO. — Farinas obtained from a variety
of tropical plants are known by this name ;
but the true East-Indian sagoes are ex-
tracted from the central part of the trunks
of Palm-trees belonging to the genus Sagus,
natives of the Moluccas. In PI. 46. fig' 23,
is figured the starch of a sago obtained
from the Museum at Kew; but it is un-
certain whether this is the produce of a
8agus ; its grains resemble those of some
East-Indian Arrow-roots (PI. 46. fio-. 18).
See STARCH.

SAGRI'NA, D'Orb. (SAGRAINA, Reuss).
See UVIGERINA.

SAL A 'CIA, Lamx. — A genus of La-
foeidae, Hydroid Zoophytes.

Char. Stem erect, composed of aggregated
tubes, branching, rooted. Cells cylindrical,
sessile, without operculum, adnate for the
greater part of their length, on all sides of
stem and branches in regular longitudinal
rows. Ovicells scattered on the stein and
branches. Polypes long, cylindrical, with
a conical proboscis.

S. abietina. Deep water off Northumber-
land coast. (Hincks, Hyd. Zooph. 211 )

SALICINE.— The alkaloid of the willow
and poplar.

The so-called circular crystals of this
substance (PL 39. fig. 9) form a beautiful
polarizing object. The largest crystals are
obtained by fusion.

SALICORNA'RIA, Cuv.-A genus of
Cheilostornatous Polyzoa.

Char. Surface divided into rhomboidal
or hexagonal spaces by ridges surrounding
the cells ; avicularia disposed irregularly. °

SAL1CORNARIIDJ5.

[ 673 ]

SAND.

S. farciminoides. On old shells, &c. from
deep water, not uncommon.

BIBL. Johnston, Br. Zooph. 355 ; Busk,
Cat. Mar. Polyz., Brit. Mus., 16 ; Heller,
Verhandl. zool.-bot. GeseUsch. Wien, xvii.
1867, 85 ; Hincks, Poly*. 104.

SALICORNARrilbE.— A family of
Infundibulate Cheilostomatous Polyzoa.

Char. Polypidom erect, branched, jointed;
branches cylindrical, dichotomous, with the
cells on all sides. One genus :
SAL i CORN ARIA.

SALIVA and SALIVARY GLANDS.
— These organs, consisting of the parotid,
the submaxillary, and the sublingual glands,
agree essentially in structure with the race-
mose mucous glands (MOUTH), of which
they may be regarded as aggregations.

Their ducts consist of connective tissue,
with numerous very dense networks of elas-
tic tissue. Wharton's duct contains un-
striped muscular fibres.

The salivary corpuscles are noticed at
page 518.

SALMON-DISEASE. See ACHLYA.
SALPI'NA, Ehr.— A genus of Rotatoria,
of the family Euchlanidott.

Char. Eyes single, cervical ; foot forked ;
carapace closed on the ventral surface, and
furnished with spines or horns at the ends.
Freshwater.

The carapace resembles a three-sided
box with convex sides, flat and closed
beneath, and often scabrous.

S. redunca (PL 44. fig. 24). Carapace with
two curved horns in front upon the ventral
surface, smooth, posterior end with three
horns; dorsum cleft, gaping. Length of
carapace 1-216 to 1-144".
Five other species.

BIBL. Ehr. Inf. 469 ; Pritchard, In/us.
SALPIN'GIA, Coppin.— A genus of
Cheilostomatous Polyzoa, of the family
Eucratiidse.

Char. Erect, branched; cells elongate,
with spines and trumpet-shaped processes ;
orifice lateral. One species :

S. Hassallii. On filamentous fud; rare.
BIBL. Coppin, Ann. N. H. 1848, ii. 273.
SALPINGCE'CA, J. Clark.— A genus of
Choano-Flagellate Infusoria. Single, in a
fixed sessile or stalked, ovate or flask-
shaped carapace. 29 species, marine and
freshwater ; attached to Algae, shells, &c.

S. amphoridiwn (PI. 53. fig. 25). Fresh-
water, on Conferva &c. : length 1-3350".
( J. Clark, Mem. Bost. Soc. i. 1868 ; Kent,
Inf. 340.)

Fig. 623.

SALTS. See CRYSTALS.
SAL' VIA, L. — An extensive genus of
Flowering plants, of the Nat. Ord. Labiataa,
including common sage, and many species
cultivated for the beauty of their flowers.
They are interesting to the microscopist
both on account of the glandular hairs,
containing the essential oils, and the spiral-
fibrous structures found in the HAIRS of the
pericarp (PI. 28. fig. 23) and the hairs of
the stigma.

m SALVIN'IA, Mich.— A genus of Mar-
sileaceae, growing floating on the surface
of stagnant water (not British).

The fructification resembles that of Mar-
silea and Pilularia, except that the anthe-
ridia and sporangia are contained in sepa-
rate sacs, and also attached to a sort of
central cellular stroma. The prothallium
of Salvinia produces several archegonia.
See MARSILEACE^E and PILULARIA.

SAND, BRAIN-. — Brain-sand, or the acer-
vulus cerebri, is found
in the pineal gland and
the choroid plexus,
sometimes also in the
pia mater, the arach-
noid membrane, and
the walls of the ven-
tricles.

It consists of single,
or aggregated and no-
dular, rounded, dark
bodies,l-2500to 1-200"
in diameter, sometimes
also forming club-
shaped, cylindrical, or
reticular masses. It is
principally composed
of carbonate and
phosphate of lime, and,
like other concretions,
leaves an organic cast Magn- 35° diame-
of the original form,
after the salts have been removed by a di-
lute acid.

BIBL. Kolliker, Mikr. Anat. ii.
SAND, SEA-. — This often contains
interesting microscopic objects, as Fora-
minifera, spicules of sponges, minute shells
of the Mollusca or their fragments, portions
of the skeleton of the Echmoderniata, &c.

The various bodies may be separated
from the washed and dried sand with a
mounted bristle.

The sand or powder which may be
separated by pressing or shaking newly
imported sponges, and which is sometimes

Brain-sand from the
pineal gland, in bundles
of areolar tissue.

SANDSTONE.

[ 674 ]

SARCODE.

called sponge-sand, is very rich in the above
organic bodies, especially the Foraininifera.

SANDSTONE. See ROCKS.

SAN'IDINE. See ROCKS.

SAP. — A name vaguely applied to the
watery juices contained in living plants.
Sap flowing from wounds may contain
various organized substances, such as starch-
granules, chlorophyll-globules, protoplasm,
and also raphides ; but it cannot be said to
have any proper microscopic characters.

SAPROLEG'NIA. See ACHLYA.

SARACENA'RIA, Defrance.— A short,
thick, triangular modification of Cristdlaria.
Recent and fossil. (Parker and Jones, Ann.
N.H. 3. xii.217.)

SAR'CINA, Goodsir.— A curious organ-
ism, formerly placed among the Palmel-
lacese from considerations relating to its
structure, but which, from its habitat and
general characters, is now referred to the
Schizomycetous Fungi. Sarcina ventriculi
(PI. 7. fig. 5 a and b) is sometimes found in
great abundance in the vomited contents of
the stomach of the human subject, also in
the stomach after death, where no disorder
had appeared during life. It consists of
minute, cubical, oblong, or even irregular
masses, of considerable consistence, com-
posed 'of four, eight, sixteen, sixty-four or
more, squarish cells contained in a tough
transparent frond, apparently composed of
the cell-membranes of these cells. The
cells are always most closely connected in
groups of four, which stand a little more
apart from each other in the secondary
groups of sixteen ; these again have a
stronger line of demarcation between them
when they are collected into tertiary groups
of sixty-four (PL 7. fig. 5 a, b). the size
of the primary cell% of nuclei of Robin
appears to vary slightly ; we find their
diameter about 1-16,000"; they have a
slight brownish tint, which imparts a colour
to the whole mass. Iodine colours the
fronds brown ; alcohol contracts them a
little. Nitric acid does not dissolve them,
even when heat is applied. Alkalies cause
the fronds to break up into their constituent
components. The plant appears to increase
by the division of the contents of its ulti-
mate cells into four and the formation of a
new membrane around each portion, the
groups remaining attached a longer or
shorter time according to circumstances.
Berkeley has in vain tried to get it to ger-
minate in sugar and water.

It is stated to have been found also in the

lung, and the pus of pulmonary abscess, the
blood, the urine, the faeces, and in the sto-
mach of the rabbit. According to Ferrier,
it is normal or constantly present in the
blood of man and animals ; and may be
readily obtained by keeping blood in tubes,
stopped with wool, for a week or ten days,
at a temperature of 100°.

We have never found it, except in the
contents of the stomach.

Robin and Rabenhorst place Sarcina in
the genus Merismop&dia ; but its cubical
form and the absence of chlorophyll at once
separate it.

BIBL. Goodsir, Ed. Med. and Sura. Jn.
1842, 430; An. and Path. Obs. 1845; Na-
geli, Einz. Alg. 2 ; Robin, Veg. Parasit. 331 ;
Rossmann, Flora, 1857, 641 ; Stephens,
Ann. N. H. 2. xx. 514 ; Ferrier, Qu. Mic.
Jn. 1872, xii. 163 ; Lorstofer, Wien. Jahrb.
1872.

SARCOCH'ITUM, Hass.— A genus of
Infundibulate Ctenostomatous Polyzoa, of
the family Alcyonidiidae.

Char. Incrusting, covered with perforate
prominences in which the cells are im-
mersed; ova scattered singly throughout.
One species :

S. polyoum. On Fucus serratus.

BIBL. Hassall, Ann. N. H. 1851, vii. 484;
referred to Alcyonidium.

SARCODE.— A term applied by Dujardin
to the gelatinous, homogeneous, diaphanous
proteine substance occurring abundantly in
very young animals, the larvse of insects,
embryos of the Vertebrata, worms, zoo-
phytes, &c. ; it is synonymous with proto-
plasm. It constitutes the whole of some
of the lower animals, as the Atncebce. It
may be readily studied when exuding from
around the body of the intestinal parenchy-
inatous worms, as Distoma, Cysticercus,
Tcenia, &c., or almost any of the Infusoria,
placed alive in water between two plates of
glass. In the course of a short time, the
bodies of the animals are seen to be bordered
with a row of projecting diaphanous glo-
bules (PI. 32. fig. 2 a), frequently more or
less pressed together, which after a time be-
come separated and float in the liquid, espe-
cially if it be shaken. Spherical cavities
or vacuoles are soon perceptible in these
globules of sarcode (PI. 32. fig. 26), the
nature of which is readily determined by
comparing the refraction of the light at
their circumference with that at the circum-
ference of the globule.-* themselves ; for on
elevating the object-glass, the centre of the

SARCONYSSUS.

[ 675 ]

SARCOSCYPHUS.

vacuoles becomes darker, and the centre of j
the globules becomes brighter ; whilst on
approximating the object-glass, the reverse
taKes place. The spontaneously produced
cavities continue to enlarge and increase
in numbers, until some of the globules !
appear perforated in all directions. Ulti-
mately the globules become so altered by |
the action of the water, that they form a
thin granular or wrinkled layer, resembling
coagulated albumen.

The protoplasm of vegetable cells corre-
sponds to the sarcode of animal structures.
In certain cells it exists in two forms as
regards density, the outer portion being
firmer than the inner; or it may become
entirely liquid. In many of the lower
organisms, and probably most cells in their
youngest state, it is glutinous, and in the
former, permanently remains so.

When existing in cells and the lowest
animals, it appears to constitute the essen-
tial part of their structure, and is capable
of performing all the functions carried on
by the tissues of the higher or more per-
fect organisms. It also appears that the
cell-theory, in so far as it attributes the
principal importance to the cell-wall, is
founded upon error — the cell-wall merely
forming a protection to the sarcode or pri-
mordial utricle of plants, and the sarcode,
or protoplast as it might be called, of ani-
mals, enabling them to carry on their
essential functions uninterrupted by sur-
rounding influences (1st Ed. 1856).

BIBL. Dujardin, In/us, p. 35.

SARCONYS'SUS, Kol— A genus of
Ixodea, with the terminal joint of the
palpi rounded or oval ; 4 species ; on bats.
(Kolenati, Sit*. Ak. Wien, 1860, 576 ; Mur-
ray, EC. Ent. 195.)

SARCOPSILLUS, Westw.— A genus of j
Aphaniptera. One species, on the fowl.
(West wood, Ent. Mn. Mag. 1875, xi. 246.)

SARCOP'TERUS,Nitzsch.— Asubgenus
of Sarcoptes. In the two anterior pairs of
legs, the suckers are replaced by claws, and
in the posterior by hairs. AS', nidulans, in
birds. (Murray, EC. Ent. 314.)

SARCOPTES, Latr.— A genus of Arach-
nida, of the order Acarina, and family Acarea.

It is, by some authors, considered a family,
being divided into several genera, as Sarcop-
tes, Symbistes, Sarcopfents, Myobia, Oto-
nyssus, Listrophortts, Myocoptes, and Der-
maleiclms.

S. scabiei (Acarus scabiei, PI. 6. tig. 16) ;
the itch-insect of man.

Body soft, white, oval-oblong or rounded ;
ventral surface with transverse and undula-
ting rugae; dorsal surface with marginal
irregularly concentric rugae, the central
space with numerous short and conical pa-
pillae and stouter but short protuberances
or spines arising from an annular base ; at
the sides and upon the surface of the body
are also scattered setae. Head small, some-
what narrowed in front j mandibles toothed.
Anterior two pairs of legs separated from
the posterior by a considerable interval ;
legs short, the anterior two pairs with aceta-
bula or adhesion-disks and five- join ted, the
posterior three-jointed, the last joint termi-
nated by a long seta and without acetabula.
Length of female 1-100 to 1-75".

The females burrow in the skin, in which
the oval eggs, 1-120" in length, are laid;
these are hatched in about ten days, and
the young have only six legs.

Male only about half the size of the
female, and with acetabula to the hinder-
most pair of legs.

The irritation produced by these mites
and their ova is the cause of the itch.

They should be searched for at the end of
one of the red streaks or burrows, which are
often visible to the naked eye ; the ova are
frequently present in the pustules. They
are most easily found by examining the
skin with a power of fifty to seventy dia-
meters, attached to a firm but moveable
arm, and with the aid of a good bull's-eye
condenser.

The entire animals may be preserved in
glycerine or solution of chloride of calcium ;
the parts of the mouth should be dried and
mounted in Canada balsam.

Other varieties or species occur upon ani-
mals, as the dromedary, the chamois, the
dog, sheep, rabbit, &c.

BEBL. Bourguignon, Traite de la Gale
(abstract in Ed. Monthly Journ. 1852, Ix.) ;
Gervais, Walckenaer 's Insect., Apt. iii. 268,
and Ann. Sc. Nat. xv. 9 ; Hering, Ej'titz-
milben d. Thiere, Nov. Act. xviii. 573 ; Du-
ges, Ann. Sc. Nat. 2. iii. 245 ; Furstenberg,
Krdtzmilben ; Murray, EC. Ent. 291 ; M<%-
nin, Paras. 158.

SARCOS'CYPHUS, Corda.— A genus of
Jungerniannieae (Hepaticae). S. Ehrharti
(Jung, emaryinata, Ehrh.) is a remarkable
species, of dark purple, almost black colour,
growing frequently in wet places, on rocks
of mountainous districts.

BIBL. Hook. Brit. Flor. ii. pt. 2. p. 114;
Brit. Jung. pi. 27; Ekart, Synops. Jung.
2x2

SARGASSUM.

[ 676 ]

SCALES.

pi. 7. fig. 56, and pi. 13. fig. 113 ; Endlicher,
•Gen. Plant. Supp. i. nos. 474-1.

Fig. 624.

Fig. 625.

Sarcoscyphus Ehrharti.

Fig. 624. Perichaete and perigone opened, showing the
young sporange emerging from the epigone. Magnified
25 diameters.

Fig. 625. Perichsete and perigone opened, showing the
ba~<> of the seta surrounded by the epigone. Magnified
10 diameters.

SARGAS'SUM, Ag.— A genus of Fuca-
cese (Fucoid Algae), gulf-weeds, known
from the allied sea-weeds by its stalked
globular air-vessels. The receptacles are
small, linear, and mostly clustered at the
base of branches, and pierced by numerous
pores leading to conceptades, containing
spore-sacs and clusters of antheridia (see
FUCACE.E).

BIBL. Harvey, Brit. Mar. Alg. p. 14,
pi. 1 A; Greville, Alg. Brit. pi. 1.

SCALAR1FORM' VESSELS. See
SPIUAL STKUCTUKES.

SCALES OF FISHES.— These bodies
were formerly regarded as epidermic forma-
tions, analogous to the nails, &c. of the
higher animals, which later observations
have shown not to be the case.

Each scale is contained in a distinct sac
of the skin or cutis, covered externally with
its pigment-layer and epidermis. The cutis
itself consists of interlacing fibres of areolar
tissue with formative cells. The pigment-
layer is composed of elegant pigment-cells
with long processes. Immediately above
the upper surface of the scales lies a very
fine membrane, distinct from the cutis, ^in
which the impressions of the irregularities
of surface existing upon the scales are
visible.

In some fishes, as the eel, the scales do
not project beyond the surface ; hence the

eel is commonly supposed to possess no
scales. They are easily seen, however, in a
dried piece of the skin, mounted in balsam,
covered by the skin with its pigment-cells
(PI. 22. fig. 19), the whole forming a very
beautiful object.

In many of the common cycloid fishes, as
the roach, dace, &c., the scales project pos-
teriorly from the surface, carrying before
them the thinner and closely applied outer
layer of the cutaneous sac, whilst the ante-
rior portion of the sac extends into or is
formed by the under portion of the cutis.
In these fishes also, the portion of the cutis
situated beneath the posterior projecting
portion of the scales contains a large num-
ber of very thin and minute crystals, to
which the silvery lustre of the skin is owing,
and which often exhibit very beautifully the
colours of thin plates.

The signification of the various parts of
structure of the scales has not been satis-
factorily determined ; hence we must con-
fine our remarks to simply pointing out the
structural peculiarities.

Most scales consist of two portions, — an
under, composed of numerous layers made
up of very line fibres taking various direc-
tions, and best seen by scraping away the
upper portion of the scale after, maceration
in dilute acid (PL 22. fig. 11 a). The upper
portion consists of concentric plates, the
margins of which give rise to the concen-
tric lines so frequently seen in the scales
(PL 22. figs. 6, 10, 22, 23, &c.). These lines
correspond to the margins of the layers, and
often present a nodular or crenate appear-
ance (fig. 11 b) ; and towards the middle
of the scales they are frequently interrupted
and irregularly curved (tig. 11 c). The <ub-
stance of the upper portion appeal's to be
structureless.

In a transverse section, the projecting
margins of the laminae belonging to the
upper portion of the scale are seen as so
many teeth (PI. 22. fig. 12.)

Many scales also exhibit radiating lines
(PI. 22. fig. 23), corresponding to furrows
in the upper portion of the scales; these
are sometimes closed above, so as to form
tubes, and have been regarded as nutritive
canals.

Near the centre of some scales, as those
of the perch, are numerous rounded corpus-
cles or solid bodies, imbedded in the sub-
stance of the upper portion of the scales
(PI. 22. figs. 6 a & 7). At the posterior
portion of the same scales are often seen

SCALES.

[ 677 ]

SCALES.

spine-like processes (figs. 6 b & 9), with
rounded or angular bodies, resembling the
last in appearance, arranged in rows at their
bases (fig. 8).

The scales of the eel appear to be princi-
pally composed of similar bodies, differing
only in form, and arranged in concentric
rows (PI. 22. figs. 20 & 20 a). They are
solid, impregnated throughout with calca-
reous matter, which is left after incinerating
the scales, retaining the original form of the
bodies (tig. 21).

In the scales of some fishes, particularly
those of extinct genera and species, lacunae
and canaliculi resembling those of bone
(PL 22. fig. 1 c), with Haversian canals, are
met with. A vitreous or enamel-like layer,
having the structure of dentine, is also met
with in the form of an external coating.

The structure of the spines or spine-like
scales of the skate is curious. The larger of
them consist of a button-like base, sur-
mounted by a sharp process (PL 22. fig. 3).
The outer and lower part of the base is
opaque-white, and consists of an imperfectly
fibrous tissue with large areolae (tig. -37).
The spine is hollow, the cavity being con-
tinuous with that of a rounded body, partly
immersed in the white substance (PL 22.
fig. 3 a). The cavity is filled with a pulp,
consisting of lax areolar tissue with minute
cells; whilst its walls are composed of a
hard substance traversed by branched canals
resembling those of dentine (fig. 4). The
substance of the smaller spines (fig. 2)
exhibits the same dentinous structure
(fig. 5).

PL 22. fig. 10 represents one of a longi-
tudinal row of scales extending along the
middle of the side of the body of most
fishes, and traversed by a tube (a), formerly
supposed to give exit to the mucous secre-
tion of the surface, which view has lately
been thrown into doubt. The tubes are
visible to the naked eye, and produce the
lateral line, as it is called.

The scales of fishes contain a large amount
of inorganic matter, composed principally of
phosphate of lime, but mixed with the car-
bonate. The organic basis consists of a
cartilaginous substance.

Some years since, Agassiz founded a
classification of fishes upon the structure of
the scales, having found that with differences
in the scales other great and important di-
stinctions were in harmony. The system
has been found of eminent service to the
geologist ; although later researches have

shown that scales presenting the charac-
teristics of those belonging to fishes of dif-
ferent orders in this system have been
found upon the same fish.

The arrangement was as follows : —

Scales enamelled.

Ord. 1. Ganoid fishes. Those the skin
of which is regularly covered with angular
thick scales, composed internally of bone,
and externally of enamel. Most of the
species are fossil, the sturgeon and bony
pike being recent.

Ord. 2. Placoid fishes. Skin covered irre-
gularly with large or small plates or points
of enamel. Includes all the cartilaginous
fishes of Cuvier, except the sturgeon ; as
examples may be mentioned the sharks and
rays. Many are fossil.

Scales not enamelled.

Ord. 3. Ctenoid fishes. Scales horny or
bony, serrated or spinous at the posterior
margin. Contains the perch and many other
existing species, but few fossil.

Ord. 4. Cycloid fishes. Scales smooth,
horny or bony, entire at the posterior mar-
gin ; as the salmon, herring, roach, and
most of our edible and freshwater fishes.

Most of the fossil fishes belong to the
first two orders, and most of the recent to
the third and fourth.

BIBL. Agassiz, Ann. Sc. Nat. 2. xiv. ;
Mandl, Ann. Sc. Nat. 2. xi., xii., xiii. & xiv. ;
Reade, Ann. N. H. 1838, ii. 191 ; Miiller,
Wiegm. Archiv, 1843, 298; Vogt, Zoolog.
Briefe, ii. ; Williamson, Phil. Tr. 1849,435,
& 1851 ; Salbey, Struct, and Growth of
Scales of Fish, Ann. N. H. 1870, v. 67.

SCALES OF INSECTS. — The fine dust
which adheres so readily to the fingers on
handling a butterfly or moth consists of a
number of microscopic flattened bodies,
called scales or feathers, upon which the
beautiful colours and opacity of the wings
depend, the membranous wing itself being
transparent and colourless.

These scales have always been favourite
microscopic objects, both on account of the
beauty and variety of their forms, and the
curious markings found upon them. The
manner in which they are attached is best
examined in the wing of a butterfly. Each
has a narrow portion at its base, forming a
pedicle or stalk. The stalks are implanted
into small and short tubes or cups (PL 34.
fig. 23 b\ denominated the squamuliferous
tubes, the orifices of which are directed
backwards. Around the points of attach-
ment of the cups to the wings, the surface

SCALES.

[ 678 ]

SCALES.

exhibits a number of irregularly radiating
rugae or folds of the upper membrane of the
wing (PI. 34. fig. 26). The cups are arranged
in more or less regular transverse rows.
Each scale is composed of two superficial
laminae, enclosing a central lamina of struc-
tureless membrane, the surface of which is
highly polished.

The scales are variable in form, both in
difTerent insects and in different parts of
the same insect, being oval, oblong, cordate,
obcordate, or cuneate, &c. (Pis. 1 & 34) ;
sometimes they are filiform or capillary
(PI. 34. fig. 27). Their free end is rounded,
truncate, toothed, or terminated by a num-
ber of hair-like processes ; and they are ar-
ranged like the tiles of a roof, overlapping
each other (fig. 26).

The interesting markings seen upon the
scales vary considerably in different insects.

The most common, as seen by transmitted
light, are longitudinal, simple, continuous,
parallel or slightly radiating dark striae or
lines (PL 1. figa. 6, 7, 8, 9 a) . These are met
with upon the scales of nearly all butter-
flies and many other insects. In some in-
sects the striae are not simple and conti-
nuous, but are made up of rows of smaller
striae in twos or threes meeting at an angle
(PL 34. figs. 28 b, 30 & 31)'. In others they
are composed of a number of bead-like dots,
or are interrupted, still preserving their ge-
neral longitudinal direction (PL 34. fig. 24) ;
or they are slightly undulate or irregular,
and give off short lateral branches (figs. 23 a
& 29). In others, again, they present dila-
tations in certain parts of their course (figs.
20 & 21).

These longitudinal striae consist of eleva-
tions or ridges upon the surface, probably
representing folds of the upper layer or
membrane of the scale. They often project
slightly from the free end of 'the scale (PL
34. figs. 3 & 22); and when moistened,
bubbles of air may not unfrequently be
found imprisoned between the surface of
the scale and the cover, which, being con-
fined between two of the ridges, assume an
oblong form. They sometimes contain air,
which may be displaced by liquid (PL 34.
fig. 21). We have never been able to de-
tect tracheae in these folds or in the scales.
A minute conical point or spine sometimes
occurs in each of the dilatations when pre-
sent (fig. 20 a).

In the scales of Podura (PL 1. fig. 12),
the striae consist of longitudinal rows of
minute wedge-shaped bodies.

In addition to the longitudinal striae, on
most scales, especially when examined by
unilateral oblique light, are seen a number of
minute transverse striae (PL 1. figs. 7 & 9 «).
These are neither indications of ridges nor
depressions, but arise from the existence of
a number of pigment-granules situated be-
tween the two layers of the scale ; and the
appearance of striae has the same origin as
that in the case of the valves of the Diato-
maceae. This point is best examined in
brown or other dark-coloured scales. If
perfectly direct light be transmitted through
one of these scales, the transverse striae
vanish, their place being occupied by the
distinct and isolated granules of pigment
(PL 1. fig. 9 6) ; the scale should also be
immersed in balsam or liquid, to diminish
the effects of the refraction arising from the
inequalities of the surface of the scale. On
then transmitting unilateral oblique light
through the scale, the appearance of trans-
verse striae may be easily produced.

The colours of the scales of insects arise
partly from iridescence, partly from the pre-
sence of pigment ; in general, the brilliant
colours depending upon the former, and the
more sombre hues upon the latter. The
darkness of the longitudinal striae is caused
by refraction ; for scales containing no pig-
ment appear perfectly white by reflected
light, although the striae may be very dark.

Upon certain scales, other irregular, more
or less transverse curved striae exist (PL 34.
figs. 3 & 22) ; these appear to consist of
wrinklings or folds of the under membrane
of the scale.

In examining the scales of insects, they
should be viewed both in the dry state, and
immersed in water, or oil of turpentine;
and both by transmitted and reflected light.
When the insects are pressed against the
slide to remove the scales, a number of
globules of oil adhere simultaneously to the
slide ; and when the cover is applied, the
scales often become partially or entirely
covered with the oily matter, producing an
appearance as if the upper layer of the scale
were removed, and rendering the markings
so pale and indistinct as to be apparently
absent. The appearance of transverse striae
is best produced by turning the mirror to
one side, so as to reflect unilateral light.

A brief notice of some interesting insects
in respect to the structure of their scales is
given under the individual heads, as Cun-
cuuo, LEPISMA, MOBPHO, PODURA, Po-

LYOMMATUS, PONTIA, TlNEA, &C.

SCALES.

[ 679

SCHISTOSTEGE.E.

See also TEST-OBJECTS.

BIBL. West wood, Intr. fyc., and Brit.
Butterflies-, Deschamps, Ann. Sc. Nat. 2.
iii. Ill ; Diij. Obs. au Micros. ; Ratzeburg,
Die Forst-Insekten ; Siebold, Vergleich.
Anat. ; Pigott and M'Intire, M. M. J. 1870,
iv. 321 ; ib. 1871, v. 3 j Watson, ib. ii. 73
& 314; Anthony, ib. 1872, vii. 1 & 250;
M'Intire, M. M. Jn. iii. 1 ; Maddox, M. M. J.
v. 33 ; Woodward, ib. v. 149 ; Beck, Qu. M.
Jn. 1864, 2 ; Mn. Mic. Jn. iv. 252; Wonfor,
Qu. Mic. Jn. 1868, 80 ; Slack, Mn. Mic. Jn.
vii. 48 ; Pigott and Beaumont, Proc. Roy.
Soc. 1873, 222; Wenham, Mn. Mic. Jn.
1874, 75 ; Woodward, ib. xv. 253.

SCALES OF PLANTS.— Under the head
of HAIRS, mention has been made of scales
(lepides) occurring on the epidermis of
plants. They consist of flat, usually more
or less circular plates of cellular tissue, the
cells presenting a radiated arrangement
from the centre, by which they are ordi-
narily attached; the margins are usually
toothed or fringed more or less regularly by
the prolongation of the free ends of the
cells. They are closely related to stellate
hairs, such as those of ivy, of Deutzia (PL 28.
figs. 26*, 27), &c., and may be regarded as
more highly developed forms of these. They
are particularly remarkable on the epidermis
of certain plants which exhibit a kind of
scurfy surface, for example
the Eleagnaceae (fig. 626),
the Bromeliaceoe, some
Rhododendra, and the
lower surface of the leaves
of many ferns ; they must
be distinguished in the
last case from the ramenta
of the stems, which are
attached by the base, and scale of the epidermis
not by a central pedicle. of Hippophae rham-

BIBL. See HAD* and a"B«,fc- .
EPIDERMIS.

SCAPHID'IODON, Stein.— A genus of
Hypotrichous Infusoria. Free, convex above,
flattened and ciliated below, pointed behind ;
mouth with a cylinder of teeth. 8. navi-
cula; marine; length 1-240". (Kent, Inf.
750.)

SCARID'IUM, Ehr.— A genus of Rota-
toria, of the family Hydatineea.

Char. Eye single, cervical, rotatory organ
armed with a hooked bristle in front ; foot
forked, very long, adapted for leaping.

Lateral processes of jaws bifurcate, so as
to present two teeth each.

S. longicaudum (PI. 44. fig. 27). Foot as

Fig. 626.

i long as or longer than the body, toes shorter
! than the foot; freshwater, length 1-72".

BIBL. Ehr. In/us. 439 ; Prit. Inf. 686.

SCENEDES'MUS, Meyen.— A genus of
Desmidiaceae.

Char. Cells fusiform or oblong, arranged
side by side in a single row of from two to
ten, after division forming two alternating
rows ; division oblique ; terminal cells often
lunate, or with a bristle at each end.

Several species (Ralfs).

8. quadricauda (PI. 14. fig. 50), Cells
generally four, oblong, rounded at the ends,
in a single row, terminal cells with a bristle
at each end. Common ; length of cells
1-1120".

8. obliquus (PI. 14. fig. 51.) Cells ellip-
tico-fusiform, after division arranged in two
distinct and generally oblique rows, end
cells lunate. Length 1-1670".

S. obtumis (PI. 14. figs. 53 & 54, just after
division). Cells three to eight, ovate or
oblong, all alike, arranged in one row, or
after division alternately in two rows. Com-
mon ; length 1-2330 to 1-1960".

BIBL. Ralfs, Brit. Desmid. p. 189.

SCEPTRONE'IS, Ehr.— A genus of
Diatomaceae. Frustules those of Synedra,
but the valves cuneiform. Several species,
marine and fossil. (Ehrenberg, Ber. Berl.
AU. 1844, 264; Grunow. M. M. Jn. xviii.
169.)

SCHIS'MA. — A genus of Jungerniannieaa
(Hepaticse), founded on a rare British form,
8. (Jung.) juniperina, /3. ewopcea, found
among rocks on the mountains of Scotland,
Ireland, and Wales. It grows 3 to 6" high,
and is rarely found in fruit.

BIBL. Hook. Br. Fl. ii. pt. 1. 124, Br.
Jung. pi. 4 ; Ekart, Syn. Jung. pi. 8. fig. 62 ;
Endlicher, Gen. Plant. Suppl. 1. No. 472.

SCHISTOSTE'GE^E.— A family of oper-
culate Acrocarpous(terminal-fruited) Mosses
of gregarious habit. Stem naked below,
foliaceous in two manners above ; sometimes
frond-like or fern-like, composed of leaves
attached vertically and connected at the
base, with dense areolations consisting of
rhomboidal prosenchymatous pellucid or
green cells; sometimes with small leaves,
like those of other Mosses, horizontal and
arranged quincuncially. All the leaves
nerveless and flat. Capsule without an
annulus, very minute, globular-oval, with a
! very small convex operculum (figs. 627-
630). British genus :

SCHISTOSTBGA. Calyptra cylindrically

SCHISTOSTEGE.E. [ 680 ]

SCHIZOCHLAMYS.

bell-shaped. Inflorescence dioecious, plants
similar.

The only species of this genus, the elegant
little Sch. osmundacea, Web. and Mohr (Sch.

Fig. 627.

Schiotobtegu osmundacea.
Leaves of barren branches. Magnified 50 diameters.

pennata, Hook, and Taylor), occurs here and
there in Great Britain. The name was
derived from what appears to have been an
erroneous observation of Hedwig, who de-
scribed radiating fissures in the operculum,

Fig. 628.

Fig. 629. Fig. 630.

Schistostega osmundacea.
Fig. 628. A plant and fruit. Magnified 10 diameters.

Fig. 629. Open capsule with operculum. Magnified
50 diameters.

Fig. 630. Young capsule opened, showing the colu-
mella. Magnified 50 diameters.

which do not exist in living specimens.
The germinating confervoid prothallium of
this moss was described by Bridel as an alga,
under the name of Catoptridium smarag-
dinum ; A gardh described it as a Protococcus
(smaragdinus) j and it was long supposed to
be phosphorescent : this appears to be an
error : tichistoslega grows on the roofs of
sandy caves and similar places j and the

luminous appearance seems to arise from
the condensation and reflection of the little
daylight admitted, by the pellucid convex
cellules of the prothallium.

SOHIZ^E'A, Smith.— A genus of Schi-
zseaceous Ferns, of curious and elegant struc-
ture : several species : exotic (figs. 081.
632).

Fig. 631.

Schizaea dichotoma.
Fig. 631. A fertile pinna. Magnified 5 diameters.

Fig. 632. A pinnule with sporanges. Magnified 25
diameters.

SCHIZ^EA'CE^E.— An order of Poly-
podiaceous Ferns.

Char. Sporangia 2-valved, opening down
the side, crowned by a complete operculiform
ring ; indusium none. Genera :

Schizcea. Sporangia sessile, in 2-4 rows,
covering one side of close distichous spikes,
which form separate fertile segments at the
apex of the fronds.

Anemia. Sporangia small, very numerous,
forming a copiously branched panicle, di-
stinct from the leafy part of the frond.

Mohria. Sporangia sessile, on the bark
of the leafy frond, near the edge.

Trochopteris. Sporangia small, sessile,
placed irregularly round the edge on the
under side of the slightly contracted lower
lobes of the leafy frond.

Lygodium. Sporangia solitary, or casually
in pairs, in the axils of large imbricated
clasping involucres, which form spikes, either
in separate pinnae or in lax rows along the
edge of the leafy ones.

SOHIZOCH'LAMYS, Br.— A genus of
Palmellaceae (Confervoid Algse). S. gelati-

SCHIZOGONIUM.

[ 681 ]

SCIIIZOMYCETES.

nosa (PI. 3. fig. 16) is found growing upon
aquatic plants or floating free, in little gela-
tinous masses composed of globular . green
cells, 1-2000" in diameter, surrounded
by a hyaline cell-membrane. The remark-
able peculiarity in this genus is the splitting
of the hyaline membrane into two or four
equal parts by regular, clean dehiscence, the
internal cell-mass becoming divided at the
same time or remaining unchanged. By
frequent repetition of this splitting, the
internal cell acquiring a new coat each time,
the cell becomes surrounded by a number
of fragments of the old coats, held together
by a gelatinous matter.

Zoogonidia produced by the division and
subdivision of the cell-contents. Macro-
gonidia and microgonidia exist.

BIBL. Braun, Verjiingung, Ray Soc. 1853 ;
Kiitz. Sp. Alg. 891 • Eabenh. Alg. iii. 32.

Fig. 633.

Schizogonium murale.

Filaments of frond in various stages of development.
Magnified 300 diameters.

SCHIZOGONIUM, Kiitz.— A genus of
Ulvacese (Confervoid Algae), nearly related
to Prasiola, distinguished by filiform fronds,
which, when youno;, present only a single
row of cells, but subsequently, by collateral
subdivision, have two, four, or eight parallel
rows. Of the species given by Kiitzing, the
following appear to be British :

S. murale (Bangia velutina, Ktz., olim)
(fig. 633). Fronds of a single row of cells
1-2400 to 1-2160" in diam. ; double, 1-1440
to 1-1260" ; triple, 1-720"; cells half as long
as broad, dull green. On damp earth and
walls, common.

S. percursum (Enteromorpha, Ag.).
Frond with a double row of cells, 1-1200 to
1-900" in diam. ; length of cells equal to the
breadth; bright or pale green; collapsed
when dry. Marine.

S. Icetevirew (Bangia, Harv.). Frond
with a simple row of cells, 1-1800 to 1-1440"
in diam., rigid ; with a double row, 1-600' ' ;
bright or yellowish green. Marine.

Bangia lacustris, Harv., is given as a
doubtful species.

BIBL. Kiitz. Sp. Alg. 350, Tab. Phyc. ii.
pis. 98, 99 ; Harvey, Brit. Alg. 1. 172, and
Marine Alg. 211.

SCHIZOLO'MA, Gaudichaud, = Lind-
say a, pt.

SCHIZOM'ERIS, Ktz.— A genus of Ul-
vacese (Confervoid Algae).

Char. Thallus capillary, flattened upwards,
fixed by a callous base; growth by cell-
division, first in one and then in two direc-
tions, so as to form cell- groups of fours. S.
Leibleinii (PI. 3. fig. 17) ; freshwater.

BIBL. Rabenh. Fl. Eur. Alg. iii. 311.

SCHIZOMYCE'TES, Nag.— An order of
Fungi.

These organisms consist of very minute,
mostly colourless cells, or filaments, occur-
ring in organic liquids, or upon organic bodies,
from which they derive their nourishment,
and the decomposition or putrefaction of
which they produce by their vegetative
growth. They are sometimes globular, at
others cylindrical, more or less distinctly
jointed, straight, undulate, or spiral. They
were formerly supposed to arise from spon-
taneous generation; also to be the early
forms of Mucedines &c., but their develop-
ment in this direction has not been traced.
Some are motionless, others move by cilia,
or internal undulatory motion. In some
cases, they secrete a gelatinous material,
which unites them into rounded masses,
constituting the so-called zoogloea-forms.
They are all insoluble in potash or ammonia.
They are reproduced by transverse division,
or by sporangia and spores ; i. e. certain of
the cells or joints are more persistent, and
offer more resistance to outer agencies.

They are stated to cause phosphorescence
upon decomposing fish.

The knowledge of these organisms is very

SCHIZONEMA.

[ 682 ]

SCHIZOXYLON.

incomplete, and it appears that mere pro-
ducts of decomposition of higher organized
bedies, and crystalline precipitates and crys-
talloids of carbonate of lime have been in-
cluded among them.

Some are recognized as the zymotic
agents in the production of disease, as Ty-
phus and Typhoid Fever, Splenic Fever, £c.
Five genera are admitted : Micrococcus, cells
globular, indefinite ; Sarcina, cells in cubes ;
Bacterium, cells or joints single or in twos,
short; Spirillum, fibres undulate, short, in •
flexible; Spirillum, fibres spiral, flexible ;
Spirochtste, fibres helical, long.

See the genera, and the BIBL. of those
articles.

SCHIZONE'MA, Ag.— A genus of Dia-
tomacese.

Char. Frustules short, straight or sigmoid,
resembling those of Navicula, aggregated in
longitudinal rows in a filiform, simple or
branched, slender and lax gelatinous frond.
Marine.

Sporangia or sporange-like bodies (sper-
matia) filled with frustules, occur within the
substance of the sheaths. This form, of
brood-sporangia, as they might be called,
appears to resemble that occurring in the
Desmidiacete (PI. 10. fig. 3 A).

The species in which the frustules are
contained in simple tubes, form the genus
Colhtonema ; those in which the tubes are
enclosed in outer tubes, the genus Micro-
mega (PL 17. fig. 8). Rabenhorst includes
all in the genus Schizonema.

Species very numerous ; Smith describes
seventeen as British.

8. Dillwynii (PI. 19. fig. 12). Frond hya-
line, tufted, wavy, lubricous, bright green,
much branched ; end branches short, nume-
rous, patent, attenuate, and somewhat acute ;
frustules towards the base of the frond
remote and scattered, towards the ends
crowded, oblong-truncate in front view;
valves lanceolate, 1-1020'' in length.

BIBL. Kiitzing, Bacitt. Ill, 8p. Alg. 97 ;
Smith, Br. Diat. ii. 71 ; Rabenhorst, Alg.
i. 265.

SCHIZONEU'RA, Hartig.— A genus of
Aphi dae . 6 species, including Aphis laniyera ;
on the apple, black currant, fir, elm, plum,
&c. (Buckton, Aphid., Ray Soc. iii. 88.)

SCHIZOPHYL'LUM, Fr.— A genus of
Agaricini, characterized by the gills splitting
along the edge and becoming revolute.

S. commune is one of the commonest exotic
Fungi, and is rare in this country, except
introduced accidentally on foreign wood.

BIBL. Fr. Obs. i. 103 ; Sow. 1. 183 ; Grev.
t. 61 ; Berk. Eng. Fl. v. 130 ; Cooke, Handb.
16.

SCHIZOPOREL'LA, Rmcka, = Lepralia
pt. Orifice of the cells semicircular or
rounded, inferior margin with a notch.
Several species. (Hindis, Polyzoa, 237.)

SCHIZ'OPUS, Clap, and Lach.— A genus
of Hypotrichous Infusoria.

Char. Marginal cirri absent, frontal cirri
and uncini present, also dorsal styles. 1 sp.
S. norvegicus, (PI. 52. fig. 20); marine.
(Claparede et Lachmann, Inf. 182.)

SCHIZOSFPHON, Kt.— Bodies as in
Stichotricha, but situated in the ends of a
branched zoary. S. socialis ; freshwater.
(Kent, Inf. 778.)

SCHIZtoSI'PHON, Kiitz.— A genus of
Oscillatoriaceae (Confervoid Algae), contain-
ing Calothrix scopulorum, fascicidata, and
perhaps other species of Harvey's ' Manual.'
Another British species has also been de-
scribed by Caspary, S. Warrenite (PI. 8.
fig. 13) ; this extends over large surfaces of
maritime rocks, in dull blackish-green tufts
of variable size, from 1-4 to 1-2" in thick-
ness. The erect filaments are fastigiately
branched («), the basal cell of the branches
broader and hemispherical (c) ; ochreal
sheaths obscure (b), frequently exhibiting a
spiral-fibrous structure in decay (d, e) ; apices
of the branches much attenuated.

BIBL. Kiitz. Sp. Alg. 326, Tab. Phyc. ii.
pi. 47 ; Harvey, Mar. Alg. 224 ; Caspary,
Ann. N. H. 2. vi. 266, pi. 8 ; Rabenhorst,
Alg. ii. 232.

SCHIZOTHE'CA, Hincks, = Lepralia
pt. Two species. (Hincks, Polyzoa, 283.)

SCHI'ZOTHRIX, Kiitz.— A genus of
Oscillatoriaceae (Confervoid Algae), of which
two British species, growing over maritime
rocks, have been described.

S. Cresivcllii(P\. 8. fig. 17). Tufts 1-2 to
3-4" high, olive-coloured ; filaments curled,
1-3600" in diameter at the base, 1-12000" at
the summit, in twisted bundles, penicillately
corymbose above.

S. Smithii (Coleonemd), Thw. Stratum
dense, dirty red ; filaments closely entwined,
more or less laterally concreted, 1-9600 to
1-8400" in diameter'; sheaths lax, multipli-
cate, the internal prolonged and exserted.

BIBL. Kiitz. Sp. Alg. 320, Tab. Phyc. ii.
pi. 40 ; Harvey, Mar. Alg. 223, pi. 26 B,
Phyc. Brit. pi. 190.

SCHIZOX'YLON,Pers.— A genus of PI*,
codei (Lichenaceous Lichens). One species ;
on oaks, rare. (Leighton, Lich. Flora, 390.)

SCHULTZE'S FILMS.

[ 683 ]

SCLEROTIUM.

SCHULTZE'S FILMS. See SILICA.

SCHULTZE'S TEST.— This was origin-
ally proposed by Pettenkofer as a test for
bile ; but Schultze found that it reacted also
with several other substances, and especially
the proteine compounds. In this application
it is often of use in discriminating one kind
of tissue or substance from another. It con-
sists in treating the matter with strong sul-
phuric acid, and then adding a little syrup.
The characteristic reaction is the produc-
tion of a purplish-red colour. The best
method of proceeding is to wash the sub-
stance in question, then to moisten it with
a drop of syrup, and finally to add the acid.

The tissues and substances affected by
it are muscular tissue, both striated and
unstriated ; nerve-tubes and cells ; the cor-
puscles of blood, pus, and mucus ; epithelial
and epidermic scales ; hairs ; feathers; horn ;
whalebone ; and the cellular portions (cell-
contents ?) of Fungi and Algae.

Those in which the reaction is not pro-
duced are areolar tissue, elastic tissue, gela-
tine and chondrine, chitine, silk, cellulose,
gum, starch, and vegetable mucus.

BIBL. Schultze, Liebigs Annalen, 1849,
CJiem. Gaz. viii. 98.

SCHULZE'S TEST.— This consists of a
solution of chloriodide of zinc, and is used as
a test for cellulose, which it colours blue.

The original directions given for its pre-
paration are indefinite ; they are as follows :
— dissolve zinc in muriatic acid, evaporate
the solution with excess of zinc until it ac-
quires the consistence of syrup, and dissolve
in this enough iodide of potassium to satu-
rate it ; iodine is then added, and the solu-
tion diluted with water if necessary.

Radlkofer recommends zinc to be dis-
solved in muriatic acid, the solution to be
evaporated at a temperature but little above
that of boiling water, when a liquid of about
2'0 sp. gr. is obtained. This is diluted with
water until its sp. gr. is 1'8 ; if its original
sp. gr. was 2'0, 12 parts by weight of water
must be added to 100 parts of the solution.
In 100 parts of this liquid, 6 parts by weight
of iodide of potassium are to be dissolved at
a gentle heat, and the mixture heated with
excess of iodine until the latter is no longer
dissolved, and violet fumes become percep-
tible over the liquid.

This reagent has the consistence of strong
sulphuric acid, and is pale yellowish-brown.
It must be kept in a well-stoppered bottle.

BIBL. Schulze, .F/ortf, 1850, 643; Schacht,
Mikroskop. 30 & 197 ; Radlkofer, Liebitfs

Annalen, xciv. 332, Chcm. Gaz. 1855, xiii.
372.

SCIA'DIUM, Al. Braun.— A genus of
Unicellular Algse. The young plant is
attached to foreign bodies, and consists of a
cylindrical cell («), in which are produced
eight gonidia ; the top of the cylinder fall-
ing off like a cap, the gonidia emerge and
form an umbel of similar cylinders (&), the
bases of which stick in the primary cell.
Each new cell repeats the process, so as to
form a compound umbel ; but the gonidia
of the third generation (c) are set free, form-
ing the primary cells of new families.

S. arbuscula (PI. 5. fig. 3); on freshwater
Confervoideae &c. Rabenhorst unites this
genus with Ophiocytium.

BIBL. Braun, Alg. Unicett. 48; Currey,
Mic. Jn. vi. 212 ; Rabenhorst, Alg. iii. 66.

SCI'RUS, Herm.,=^c7e//«pt.; including
the species with apparently a head and neck.
5 species, found among mosses, on insects, &c.
(Murray, EC. Ent. 144).

SCLEREN'CHYMA. See TISSUES,
VEGETABLE.

SCLEROCHI'LUS, Sars.— One of the
Cytheridce, with smooth, hard, elongate,
bean-shaped valves ; lower antennae 5-
jointed ; upper 6-jointed, with long setae ;
eye single. One living British species;
common. (Brady, Linn. Tr. xxvi. 455.)

SCLERODER'MA, P. — A genus of
Trichogastrous Fungi having a firm peri-
dium, which bursts irregularly, containing
large granulated spores separated in masses
by floccose veins.

Four species have been found in this
country, one of which when young is sub-
stituted for truffles, though without any of
the fine aroma.

BIBL. Fr. Syst. Myc. iii. 46 ; Berk. Outl.
t. 15. f. 4 ; Cooke, Handb. 374.

SCLEROT'ICA. See EYE (p. 310).

SCLERO'TIUM, Tode.— A large collec-
tion of fungoid structures were formerly
gathered together under this name, among
others the preparatory form of the ERGOT
fungus. They are now all regarded as
consisting of the mycelia of fungi in an
imperfect state. The sckrotioid state exists
when the mycelium forms hard tubercular
masses. Analogous masses of mycelial
structures occur, in a pulpy condition, in
the Vinegar-plant; in a filamentous con-
dition, in those fungi forming large masses
of barren byssus, &c. ; in other cases, as in
some of the Myxogastres, the structure is
membranous.

SCOLIOPLEURA.

[ 684 ] SEBACEOUS FOLLICLES.

BIBL. LeVeiUe", Ann. Sc. N. 2. xx. 218;
Berkeley, Hort. Jn. iii. 97 ; Fries, Sum.
Veg. 477.

SCOLIOPLEU'RA, Grunow.— A genus
of Diatomaceee. Frustules those of Na-
vicula or Pinnularia^ with the median line
and hoop curved.

BIBL. Grunow, Wien. Verh. 1860;
Rabenh. Alg. i. 228.

SCOLOPEN'DRIUM, Smith, Hares-
tongue. — A genus of Scolopendrieae (Poly-
podiaceous Ferns), represented by the indi-
genous species Sc. vulgare (fig. 221, p. 319).

SCOLOPENDRIEJ5. — A family of
Polypodiaceous Ferns ; containing the single
genus Scolopendrium.

SCRUPA'RIA, Hincks. — A genus of
Eucratiidse (Polyzoa). S. clavata, on other
Polyzoa. (Hincks, Polyz. 21.)

SCRUPOCELLA'RIA, Van Beneden
(Cellularia, Johnst., pt.). — A genus of Chei-
lostomatous Polyzoa, of the family Cellula-
riidaB.

Char. Cells with a vibraculum behind,
and a sessile avicularium at the upper and
outer angle; orifice spiuous. Five species.

S. scruposa. Cells without an operculum.
Common on Algae, &c.

S. scrupea. Cells with a stalked reniform
operculum.

BIBL. Johnston, Br. Zooph. 336; Busk,
Ann. N. H. 1851, vii. 83; Hincks, Polyz.
43.

SCUTELLID'IUM, Clans.— A genus of
Copepoda. 2 species, on Laminaria. (Brady,
Copep. ii. 175.)

SCUTOVER'TEX, Mich.— A genus of
Oribatidae (Acarina), allied to Erem&us.
S. sculptus, brown-black. (Michael, Jn. Mic.
Soc. 1879, ii. 241 ; 1880, 177.)

SCU'TULA, Tulasne. — A genus of Coc-
cocarpeae (Gymnocarpous Lichens), para-
sitic, found upon Peltigera canina.

BIBL. Tulasne, Ann. Sc. Nat. 3. xvii. 118;
Lindsay, Qu. Mic. Jn. 1869, 140.

SCYPHID'IA, Duj.— A genus of Peri-
trichous Infusoria, family Vorticellina.

Char. Body oblong or campanulate, nar-
rowed at the base, which is very contractile,
covered with a reticular integument.

8. rugosa (PL 31. tig. 74). Body with
oblique striae or rugae, not numerous ;
freshwater; length 1-550". Four other
species.

BIBL. Clap. &Lach./rc/. 116; Kent./w/.
658.

SCYP'HIUS, Koch.— A genus of Trom-
bidina (Acarina). S. diver sicolor, very

minute, in damp moss, under decaying
leaves, £c.

SCYTO'MONAS, Stein.— A genus of
Flagellate Infusoria. Free, ovate, form
persistent, flagellum single, no mouth. S.
pusilla; freshwater; length 1-1000". (Kent,
Inf. 241.)

'SCYTONE'MA, Berk.— A genus of Os-
cillatoriaceae (Confervoid Algae), especially
distinguished by the mode of branching of
the filaments. We can only make out with
certainty one British species of the genus as
now restricted, S. Myochrous (PI. 8. fig. 19),
which grows in alpine bogs and rivulets,
and is composed of decumbent filaments
interwoven into a dark- brown stratum.

BIBL. Harvey, Br. Alg. 1. 155 ; Hassall,
Alg. 235, pi. 68 ; Kiitz. Sp. Alg. 303, Tab.
Phyc.

Fig. 634.

Compound sebaceous eland, IVom the nose, opening
upon the surface with a hair-follicle, a, b, c, as in the
next figure ; d, lobules of the compound gland ; e, hair-
follicle (root-sheath) ; /, the hair.

Magnified 50 diameters.

SEBACEOUS FOLLICLESon
GLANDS. — These organs exist pretty

SEBACEOUS FOLLICLES. [ 685 ] SEBACEOUS FOLLICLES.

generally in the skin, and secrete a fatty
matter. They are mostly seated close to
the hair-follicles, into which their ducts
usually open. They vary in form, some

Fig. 635.

Simple sebaceous follicle, from the nose, a, glandular
epithelium, continuous with b, the rete mucpsum ; c,
contents of the gland, consisting of cells containing fat,
with free fatty matter.

Magnified ."0 diameters.

Fig. 636.

Glandular vesicle of a sebaceous gland, a, epithelium'
ontinuous with the glandular cells b, containing fat.

Magnified 250 diameters.

Fig. 637.

Cells rom the glandular vesicles and the sebaceous
secretion, o, small nucleated cell, containing but little
fat, and resembling an epithelial cell ; 6, cells abounding
in fat, without evident nuclei ; c, cell in which the fat-
globules are becoming confluent; d, cell containing a
single drop of fat ; e,f, cells from which part of the fat
has escaped.

Magnified 350 diameters.

being simple pouches or depressions of the
skin, whilst in others the deeper part of the
pouch is branched, so as to constitute a true
racemose gland. The narrower portion, or
duct, is variable in diameter ; it usually
opens into the hair-follicle, rather above its
middle, but sometimes upon the surface of
the skin itself.

Each gland consists of an outer coat of
connective tissue, forming a more or less
thick membrane in proportion to the size of

Fig. 638.

Development of the sebaceous follicles in a six-
months' foetus, a, hair ; b, inner root-sheath ; c, outer
root-sheath ; d, rudimentary follicle.

Magnified 250 diameters.

Fig. 630.

a, b, c, d, as above, but in a more advanced stage.
Magnified 250 diameters.

SECONDARY DEPOSITS. [ 686 ] SECONDARY DEPOSITS.

the gland ; this is derived either from the
hair-follicle or the cutis, according to the
situation ®f the gland. It is lined by layers
of roundish or polygonal, epidermic or
epithelial cells, the outermost of which
are closely connected, so as to form one or
more membranous layers, and contain few
or no globules of fat ; whilst the inner ones
are larger, and almost filled with these glo-
bules.

The development of the sebaceous glands
commences at the end of the fourth or in
the fifth month. The glands at first consist
of solid depressions or outgrowths of the
rete mucosum of the skin, or the inner
root-sheath of the hairs ; the inner cells
then become filled with fat, loosened, and
are finally evacuated through that part of
the immature gland which in its subsequent
development forms the duct.

BIBL. Kolliker, Mik. An. i. 180 ; Biesia-
decki, Strieker's Hist.

SECONDARY DEPOSITS OB
LAYERS OF VEGETABLE CELLS. — The
structures known by this name are spoken
of under CELLS, in a general point of view,
and in detail under PITTED and SPIRAL
STRUCTURES. A few remarks may be given
here, connecting the phenomena included
under the last two heads.

It is well known that the original or
primary cell-wall, the layer of cellulose by
which the cell first becomes really consti-
tuted as a closed membranous sac, is, so far
as our present instruments enable us to
judge, devoid of detailed structure : it is a
homogeneous pellicle. This has a power of
extension by interstitial nutrition, which
leaves no traces in the perfect membrane,
enabling the cell to increase in size. But
the increase in solidity is effected by a
different process, leaving distinct evidences
of its occurrence, namely by an application
of successive thin layers of cellulose mem-
brane, more or less completely all over the
inside of the primary membrane, giving the
cell-wall a laminated character, either evi-
dent in the natural condition, or capable of
being demonstrated by the aid of macera-
tion or corrosive applications.

No cell which is to form part of a perma-
nent tissue remains long without receiving
secondary layers upon its walls. In certain
cases the wall exhibits in its natural state
merely the laminated structure, without
any markings (PI. 47. fig. 24) ; but in the
majority of cases, where the secondary de-
posits are considerable, these layers exhibit

markings of very peculiar characters. As a
general rule, the layers present themselves
under two different types, according to the
extent to which they cover the primary
membrane. In one case they are applied as
a general layer over the wall, absent merely
at dot-like or slit-like points, where they
leave the primary wall uncovered, and thus
give rise to a pitted condition as seen from
the inside of the cell. Successive layers
leaving the same spots bare, the pits become
gradually deeper, and form canals running
through the thick cell-wall to the primary
membrane (see PITTED STRUCTURES) (PI.
47. fig. 23).

Another curious condition of the secon-
dary deposits has been pointed out by Hartig
and Monl, where large patches or spots upon
the cell- wall, especially at its base, are left
bare by the thicker secondary layers, and
become coated with a thin layer perforated
by minute orifices, as if riddled with holes,
or reticulated; this is called a sieve-tube
or clathrate tissue.

In the other case, the secondary deposits
are more sparing in quantity, and are ap-
plied over lines forming a definite pattern
upon the primary membrane, in which a
spiral course in the direction of the long
axis of the cell is more or less evident;
infinite modifications of this type occur,
which are treated of under the head of
SPIRAL STRUCTURES (PI. 48. figs. 7, 9).

In certain less common cases we fina the
earlier secondary layers exhibiting the pitted
character, while others later-formed produce
spiral-fibrous thickening, as in Taxm, the
lime, and other cases (see PITTED STRUC-
TURES, PI. 48. figs. 4, 13, 196).

The last-mentioned cases point to a rela-
tion between the spiral-fibrous and the
pitted layers, which appears really to exist,
lor in a great number of cases it is possible
to distinguish a spiral structure in the
membranous layers of pitted cells, or even of
cells where the layers of thickening merely
exhibit the laminated structure without any
pits or fibrous markings. Thus, in the liber-
cells of the Apocynaceae (PI. 48. fig. 30),
the thickened Avails appear under a low
power homogeneous, while under higher
magnifyingf-power, and especially by the
help of acids, we may detect an evident
though delicate spiral structure. The action
of acids reveals a similar spiral arrangement
of the constituent molecules, in the cotton
hair (PI. 28. fig. 1), and in most liber-cells
(figs. 2, 5, 25), in many wood-cells, as of

SECONDARY DEPOSITS. [ 687 ] SECRETING ORGANS.

Pinus, &c. The membranes forming the
sheaths of many of the Oscillatoriacese
(PI. 8. figs. 13 d, e, 16) exhibit a spiral-
fibrous structure when undergoing dissolu-
tion ; and an analogous condition may be
detected by the help of reagents pretty
generally in the cell-walls of the tubular
Confervse. All these phenomena seem to
indicate a fundamental identity in secon-
dary layers of all kinds, to which we direct
attention under SPIRAL STRUCTURES ; but
it is convenient to keep the PITTED and
SpiRAL-fibrous structures distinct.

The mode of formation of the secondary
deposits is not clearly known : some imagine
them to be precipitated from the cell-sap
upon the walls ; others, and apparently with
more reason, believe that they are attributable
to the agency of the PRIMORDIAL UTRICLE,
continuing its action after the formation of
the primary membrane. Criiger goes so far
as to consider the spiral markings, &c. as
dependent on the RoTATiON-currents of the
protoplasm. There can be little doubt of
the mistaken character of Trecul's view,
which regards the spiral and other fibrous
thickenings as folds of the primary wall
thrown inwards.

The secondary deposits appear to be always
composed of some modification of cellulose.
Mohl has investigated this point very
thoroughly ; and we have followed him over
much of the ground. The cellulose, how-
ever, loses its distinctive character with
age, either by infiltration with foreign
matters, or by a slight chemical metamor-
phosis, so that old secondary layers do not
readily become blue when sulphuric acid
and iodine are applied; but as a general
rule the cellulose reaction may be obtained
by using a preliminary treatment. All in-
ternal structures, such as wood-cells, liber-
cells, stones of fruits, &c., should be boiled
in nitric acid, washed, dried, and tincture of
iodine applied; then, if again dried and
wetted with water, they turn blue. Ex-
ternal structures, such as epidermal cells,
cork, and the like, require boiling with solu-
tion of potash.

Secondary deposits present considerable
difference in their consistence and degree of
development in different cases. In most
wood- and liber-cells they are abundant in
quantity, in some cases almost filling up
the cavity (PI. 47. fig. 27) ; here they are
hard, and! appear to be in that state of the
cellulose-compound which may be distin-
guished as lignim. The same condition

prevails in the stones of fruits, bony shells,
the gritty tissue of pears, &c. j and the less
abundant secondary substance of spiral-
fibrous tissues appears to be in the same
state. The secondary layers of parenchy-
matous cells are usually rather soft and
elastic, and often turn blue with sulphuric
acid and iodine alone ; those of the collen-
chymatous tissue beneath the epidermis of
many herbaceous plants, such as the Che-
nopodiaceae, &c., are abundant in quantity,
but of somewhat cartilaginous texture.
Those of the larger Algae, and of the thallus
of the larger Lichens, approach to the same
condition, while the fleshy and horny AL-
BUMEN of many seeds contains abundant
deposits of analogous character (PI. 47.
figs. 21-23) ; in the latter the composition
is sometimes of amyloid, approaching starch,
stained blue by iodine alone, and more or
less soluble in dilute sulphuric acid. The
secondary layer of epidermis and corky layers
differs again, being usually more sparing in
quantity, but very firm and elastic, and
strongly resisting decomposing agents ; the
composition appears to be of that modifica-
tion of cellulose called suberine.

BIBL. Mohl, Vegetable Cell, 1852, Hot.
Zeit. 1847, 97, Taylor's Scientific Memoirs, 2.
i. 95 ; Schacht, Pflanzenzelle, 1852 ; Criiger,
JBot . Zeit. xiii. 1855, 601 ; Trecul, Ann. Sc.
Nat. 4. ii. 273 ; Wigand, IntercelMar-sub-
stanz, 1850 ; Mulder, Phys. Chem. ; Henfrey-
Masters, Bot.

SECRETING ORGANS OF PLANTS;
RESERVOIRS OR RECEPTACLES for SECRE-
TIONS.— The structures falling under this
head have been in part treated of under the
heads of GLANDS and LATICIFEROUS TIS-
SUE ; but there still remain certain organs
of analogous character, which could not be
properly included under either of the above.
The name of receptacle or reservoir for
peculiar secretions is ordinarily applied to
groups of cells, of variable, but most fre-
quently elongated prismatic form, contain-
ing special secretions, either in their ca-
vities or effused into their intercellular
passages, traversing in the form of cords or
bundles the parenchymatous or prosenchy-
matous tissues. They are almost special
characteristics of families, and by no means
frequent; the Coniferae, the Cycadacea3,the
Aloineous Liliacese, the Polygonaceaa, Com-
positae, Umbelliferae, Amygdaleous Rosacese,
Leguminosae, &c. afford striking examples.

In the Coniferae the turpentine-reservoirs
are very remarkable ; and to a certain extent

SK(TIO\S.

SKKDS.

they render it piiS-ib!e ID determine (he

genii,- by their arraii/eiiienl. In /'////« I liey

Con; i t . ,|' bllll<lle nf elollgatl ,il|e<|

cells, running through the wood parallel ID
the a\i.-of (ho Stem. These 1 hill-Will I cells

an- densely tilled \\ it h I n i -pent ine ; in .-nine
cases the cells of the medullary rays ar(
likewi e Idled \\ilh turpentine, and, I. \dl •

1 he.,c, pei-jn ndieiilar ill I ercel I II I;.

the latter form of turpentine-canal M chiefly
met \\il.h in the bark. Turpent in,
also exist in the leaves of the < Jonifera-, the
scales of the cone,, Ac.

Tin , .if t he Aloe^ nre bundles

of pn.-matic Cells accompanying ll .
lar bundles of the leaves ami itemt, TJm
colouring-matter of tlie root uf rhubarb is
contain' d in c. 1 1 - of iinj,.-i feel medullary
rays. The .structure of the balsam
voirs of the m\ rrh tree, \t>. |,;,., Moi b . n
thoroughly studied. Tlie resin- and oil-
canals of the I mbellifenn are of gre.,1 im-
portance; but the former, chiefly occurring
in the roots, an- imperfect I \- known. The
of the iriiifs (wtf(p) consists of
excavations in the cellular tissue,
tilled \\ ith oil. ( 'anaU containing od.
rous oils occur in home of the ( 'ompo.-iia'.
li'e.-iin-cannls occur also in the common lime,
(iiim-canals, consisting of simple ,,r
})rnnched intercellular passages with a spe-
cial coat of small secreting colls, occur in
the leaf- talks of ('ycudacea', the bark ..f
the Aniyt/thlfrr/;\\n>. stems of the .MalvilCCCe,
( 'aetaeea-, \c. Structures of similar nature
contiiiu the milks juices of certain plants, as
the Anacurdiacea- ; and t hese appea r t .. be
dilli'ivnt from the ordinary LSII x \. s<>ls.

I'.i in.. Meyen, -Vc/v/. -Ori/ane d. Jy/
1887,18; linger, .///. wid I'/iyn. <ltr I'/lnii-
zen, 18/55,204; \. 'lie^-hem, An. /S'c. Aft/.
1*7^, xvi.; Sachs, lint. 71).

SUCTIONS. See I'nKi-AirviioN'; and
for SchieH'erdecki r's section-cut! er,*SV7/ ////.-., '.s
Arch. 187(5, xii. 1)1 ; a modilication, Kiddy,
(J><. Mic. Jn. 1877, xvii. U6; and Lewis,
M. ,)/..///. \vii.;U)0.

SMMDS. These III-H interesting oltjeds
for microHCOpic exaininntion in respect to
many dillerent cluiracteri:-tics. Among
them may be mentioned lir^f the vnriety of
beautiful markings upon the surface, \\hich
render almost all >eds, like the c-lytra, of
beetles, interesting opaque objects for ob-
servation with n low po\\er. A few .-trik inn-
forms lire lepresented ill IMate .".H. li

JH ; and we give a list of kinds easily to be
obtained.

Lychnis,
StcUorio,

/(V.SVY/,/.

A ifnl'niiut.
I'i' I nn in.

nyotoyaimts,

<SV III/TI rii 1/1,1.

fit f /ft.
Cii/i/ifirix. Xili'itr (IM.

Brioa, /•:/<//;,«•. i<;. i; ,

AnaaaiKt, (;<'»iirr<t. Dimitlm* < ri. ;;:>.

Orolxui,-/,,'. !;<</<,, iin. li;.-. | .', i.

/.inarm. l)<'li>liininin. J'n/>n/-f /• ( I'l. .'!'.».

( 'Inroiiin. Kr/;,/i/,/i/{i//'n. li^. M).

M> . ni'runnllicinum. Jig. |H).

The foil owing are Well s< en \\-hen mounted
nl objects in Canada b,il>am.

Hi. Mnnnli;,/!!!.

Orchis. Hi/dm nij <-ii.

The i,-*i,i or outer skin of some of the
hitler (al.o l!< (/nn in ), \\ hen r'ino\ed from
the seed and viewed with a hi-h pov, ,
hibita elegant pitted ceil,. Theaur&oeol

the 1 . d ,,|' ( ',,/.„ n i . meals u ilh little .s, jd, s
'ing of pyriform colls containiii"- a
spiral fibre (I'l. L'S. |j,r. j(),.

The surface ,,f \aiious seeds, such us Cnl-
li'inin and /•'///•///«, and the pei it arp of ma ny

ed like fi nits, .-iich as that ol A//// /*/ ai.il

•nn in, pi-. M-nl i.-niarkable II AIKH.

'I he stones of plums or ch.iii. . >
called shell of the Cocoa-nu! and
fruits, exhibit remarkably thick SIM OKI) Oil
DBPOtlTfi

The examination of the structure nf ripe
seeds is a matter of great importance in
botany. The inrestigation wiU MUT much
according to circumstance*, Where si

are large, the micro, cope is only reijiiii d
for the examination of their li — lies; h;il
.-•mall . .ids must be examined by dis.-ection
\\ith needles under the simple mi<

or by sections, \\ hi, ! i easily made

by lixill;..' I he D||, mil , e(| into n, piece nf

wax. Seeds have two coats, the testa and
//<//, or external and internal membrane,

and, in-curding as the seed is or is nnt albu-
minous, an albumen enclosing theembrM,,
or an embryo of larger size immediately
invested by the coats. The chanu ters of
the Ai.nr.MKN mid LMIUIYO will be found
under these heads, as also other particulars
under ( )\ i I.K. l'!iiibr\os n.iv either . Moiio-
colylodonous or Dicotyledonous; sometimes,
however, the two cotyledons are s,,lder,d

together more or less '« plelely. in the

Conifer^ and certain genera of Dicotyle-

8EIROSPORA,

|

don, us Aiii/iosperms. :is Xc/ifzo/>cf<i//ni>. the
cot\ ledons appi ;ir to he lour. six. or QBOW
in niimlier ; hut tin- observations of l)u-
chartre show that there exist only two —
bifid, iriliil. en- mnltilid cot \ ledons. In
Other Cases, a- in O/v///-s tin- emhiyo remains
imperfectlv de\ eloped. ;ind appears :is a
mere cellular mass in tin- ripe seed before
germination: this is destitute of alhumen ;
hut in ( h-ofi(i>ic/n' :in amorphous embryo IS
found imhedded in tin- albumen.

Mini., (iriit-ntf inn-ks <>n /infant/.

SLlKOS'l'ni; A. llarv. A genus of (V-
ramiaceie ( MiorideoiK AlgM'i, containing oae

rare species, ,S'. (i'ri//i(/isiint<i, -,\ lit tie crimsoii

feathery sear-weed.oompqiea of sinrle jointed

tubes, {ho joints being fra versed by artjcu-

hilrd filami -ills. The spores an- unknown;

hill Illi- I, /ntSfinrt'fi. \\ ll'u'll srl'\r lodislill-

piisli this |)l:nit rn.in tin- (\illitlnunnin. occni'
in l<Tinin:il h.'iidcd fltrings, being formed
out of tin- raiuidi.

Mi i-.i.. Harvey, Mar. Al<j. 170.
SK'.irs, l\ocli,= rrV/;/^/.wx, pt. (Koch,
r^r.v. 1L': Murniy, AV-. lint. 104.)

SELAGINEL'lJA, !>«• Beaov.— ATODUI

of L\co|Hidi:ic.';c, disi iii^uished from Li/r,,-
jHHliuin hy 111-1 presence ,,f two kinds of
f-)i<,ivs iini'i I In- dissimilar habit.

This p:onus includes only one of our
native ('lull-mosses, S. .^>///n,sv/s ( Li/r. xc/df/i-
noi<h'*}\ l)ilt most ol'tlie so-called LyOMKNWI,
in»\v so e\lensi\ely cultivated in Wnrdian
OMBt, i'eni-hoiisrs. \-c., liclon«r to this di\i-
S'IIMI (ti-. l'^'s,p. 481). The principal parti-
culars relating to these plants, especially
Ihe reiuarl\ahl<' history of thereproducti. in hy
Ilie spores, are niven under LYCOPODIA-

Mir.l.. See |,NC(.|'(t|.|A' '

SKI.KMTK. rrhis well-Known mineral
8uhst:ince consists of crystsiHi/.-d hydrate,!
sulphiitc of lime. Its crystals belong to the

ohliqne prisn: in : and tin1 colours

exhibited bv thin laminre, into which they
may be easily split, are very beautiful under
p.'hiri/ed light. Polarizinff cry.-tals :ind
;mic sulistiinces. in \\hieh the Ihickness
is not suited to the production of distinct
colours under the polariscope, may be made
to exhibit them by placing a plate of sele-
nite heiie;ith the object. For this purpose,
the phite is usually kept mounted in Canada

hals;im. See Pol.AIM/ATHiN.

SI-;LK;I-: IMA. r.r. & Sch.— A g.-nus of

'u-liacroii-i Mo- es, including cerlain
- of authors : ha\ii:Lr th«> leaves seta-

on-. ;md the ••:ipsiile< pyrifomi.

Si;M)TM<:KA, Woods.— A genus of

|

Juager ntaanieA | Hep*tic»), mostly tropical;

• Mil- species of which. -V (Jii)HJ.) /( /1,.,/x/V.

occurs rarely in the mountains of the S.W.
of Ireland (de\oid of fruit ).

•'•MM.. 1 1. .ok. llr. /•'/. ii. pt. 1. IL>({; /.V.
./*/////. plJ'.C.; MKart, .S'////. ,Ju,nj. pi. VI. f. 108;
Kndlicher. Gen. Vlanl. Supp. L;No. 473 H'.

SMN !•;•( '!( ). The surface of the acheenia
or seed-like fruits of the common groundsel
(Senteio nift/tin*) is sparingly clothed with
!l\ii;sofa peculiar character. These ap-
l>ear to consist of two M>III {cylindrical cells
a implied to--ether by their flat faces, so as to
form a Kind of tube with a vertical septum.
\\ hen placed ill water they expand some-
what, and the contents are expolfed from the
ends, consisting of an indistinctly spiral-
fihrou.s structure, \\hidi untwists' ami ex-
pands by the absorption of water, to twice
or three times the length of the hair . in a
manner comparable in some degree to the
h'ha\iour ot the contents of the hairs of
AC\MHA< i:.i:. (Lei-.rluon.-4wn. N. H. vi.

L'.V.'.I

S I ; I ' !• I )( )M ML— A family of Ilyphomy-
ceious I'ungi, consisting of a hetexogeneoQi

assemhla-'e of imperfectly Known genera,

and differently defined bv differanl authois.
Those nvnera'we have include.l in onr list
are enumerated in Lindley's ' X'e^vtahle
Kingdom;' but 1-Vies includes Oiilhnn and
others. '1'he general cliara< (er of the fjimily
is, that the plants produce spores 1\ ing im-
mediately umm the decumhent tilaiuents
of the mycelium, or upon short pedicels.
Genera;

Arfntrniin*. luitophytic; tilaments creep-
ing1, persistent; spores springing from the
middleof the filaments, simplest length free,
spinous.

Hr/)itinninm. Filaments woolly, septate,
exanescent ; spores o'lohosc, connate, scabrous,
stalked, solitary, at len; ih heaped to^ciln-r.

I-'itfiin/mrinni. Spores fusiform or cylin-
drical, glued toget her in heaps resting on t he
gelatinous matrix.

J-:/i<></,,iiuin. Spores heaped, oblong, api-
culate, septate, adnate to the matrix, inter-
wo\en \viil, the ell'iised, entangled, slender
filaments of the mycelium.

/'.fi/ttnirt. Spores simple, pellucid, not
glued together, at first covered by the con-
verging tilaments of the mycelium.

Mnnotituftnra. Epiphytic"; filaments creep-
• an. scent; spores globose, solitary,
terminal, at length free.

A.<t, roplinra. Filaments creeping, ranmli
branched, the fertile terminating in a spiral

SEPEDONIUM.

[ 690 ]

SERTULARIIDJE.

coil, composed of about 3 joints, one of
which swells into a rough-coated spore.

Zygodesmus. Filamentscreeping, branched,
with short ram uli bearing echinate spores, the
pedicels with a lateral indentation looking
like a joint.

SEPEDO'NIUM, Link.— A genus of Se-
pedomei (Hyphomycetous Fungi), contain-
ing two species, growing upon decaying
Fungi. & chrysosperma has golden-yellow
spores, S. roseum red ones. The first is
common. The species are all forms of
Sphseriacei.

BIBL. Berk. Br. Fl. ii. pt. 2. 350 ; Fries,
Sum. Veg. 497 ; Grev. Crypt. Flor. pi. 198.

SEPIA, Linn. — A genus of Cephalopoda.
The structure of the dorsal internal shell of
S. officinalis, the cuttle-fish, called the cuttle-
bone or sepiostaire, presents a curious struc-
ture. It is oval, flat, convex, horny outside,
the interior being calcareous and composed
of numerous friable, horizontal, parallel, cal-
careous plates, separated by innumerable
minute perpendicular flattened columns,
with transverse thickenings at pretty regular
intervals, producing a striated appearance.
When mounted in balsam, it forms an in-
teresting polarizing object.

SEPTONE'MA, Corda.— A genus of To-

Fig. 640,

rulacei (Coniomycelous Fun-
gi), related to ~Torula, and
connecting this in some mea-
sure with Dendryphium. S.
spiloma, forming green tufts
on old rails, has been found
in Guernsey. Several spe-
cies are recorded as French
by LeVeiUe", one forming
patches on vine-leaves, the
others on the potato. The
chains of septate spores soon
break up.

BIBL. Corda, Ic. i. & ii. ;
Fries, Sum. Veg. 504; Le"-
veille", Ann. Sc. Nat. 3. ix.
261 ; Berkeley and Broome,
Ann. N. H. 2. v. 461 ; Berk. Septonema viride.
Lond. J. Bot. iv. t. 12. fig. 5. Magnified 150

SEPTO'RIA, Fr.— A ge- diameters.

nus of Sohaeronemei (Coniomycetous Fungi),
but probably in reality consisting of pre-
paratory forms of Sphcerice. They grow
upon the leaves of plants, the fusiform sep-
tate or inarticulate thread-like (( spores "
oozing out from a pore in the form of a
tendril.

S. Ulmi and S. Oxyacanthce are common ;
numerous other species are recorded.

BIBL. Berk. Br. Fl. ii. pt. 2. 356 ; Berk,
and Br. Ann. N. H. 2. v. 379, xiii. 460 ;
Tulasne, Ann. N. H. 2. viii. 117, 4. v. 115.

SEPTOSPO'RIUM. See MACROSPO-
BIUM.

SERIALA'RIA, Lamarck. — A genus of
Vesiculariidae (Polyzoa). S. lendiyera, the
only British species, is not uncommon on
Fuci, near low-water mark. (Hincks, Poh/z.
515.)

SEROUS MEMBRANES.— These con-
sist of the same elements, arranged in the
same number of layers as in the Mucous
MEMBRANES. The thickness of the layers,
however, is considerably less, the fibrous
elements are finer, and the epithelium forms
a single layer onlv of polygonal cells. The
communication of the lymphatics with the
so-called stomata is noticed at p. 485.

BIBL. That of TISSUES, ANIMAL.

SERRA'TOR, M^gnin. See ACARUS,
p. 5 (Me"gnin, Paras. 144).

SERTULAREL'LA, Gray.— A genus of
Sertulariidse (Hydroid Zoophytes).

Char. Cells biserial, alternate, with a
toothed orifice and an operculum composed
of several pieces. 8. rvgosa (formerly Ser-
tidaria r., PI. 41. figs. 11 & 12); common
upon Flustrce, Fuci, &c. at low-water mark.
(Hincks, Br. Hydr. 234.)

SERTULA'RIA, Linn.— A genus of Hy-
droid Zoophytes, family Sertulariidae.

Char. Polypidom plant-like, fixed by its
base, variously branched, the branches
formed of a single tube, denticulated or ser-
rated with the cells, and jointed; cells alter-
nate, semialternate, or opposite, biserial,
sessile, urceolate, with everted apertures ;
ovarian vesicles scattered.

Many of these elegant zoophytes, which
would at once be referred to the vegetable
kingdom by any casual observer, are com-
monly found on the sea-coast, either loose
or attached to shells, sea-weeds, &c.

S.pumila (PL 41. figs. 13 & 14). Cells
opposite, approximate, shortly tubular, the
top everted, with an oblique somewhat mu-
cronate aperture ; vesicles ovate ; common
on Fuci near low-water mark.

S. operculata (PL 41. figs. 15 & 16). Cells
opposite, inversely conical ; aperture patu-
lous, obliquely truncate, pointed on the
outer edge, and with two small lateral
teeth ; vesicles obovate.

BIBL. Johnston, Brit. Zoophytes, 61 ;
Hincks, Hydr. Zooph. 259.

SERTU'LARITD^.— A family of Hy-
droid Zoophytes.

SETOSELLA.

691 ]

SHELL.

Char. Capsules quite sessile on a horny
polvpidom ; egg-germs contained in scattered
deciduous capsules. British genera :

Halecium. Polypidom plant-like ; stem
consisting of several parallel tubes ; cells
shallow cups, on opposite sides, alternate,
one under each joint.

Sertularia. Plant-like ; stem simply tu-
bular, branched, jointed; cells vase-like,
alternate or in pairs, on opposite sides, with
everted rims.

Reticularia. Polypidom an investing net-
work of horny tubes, immersed in a homo- •
geneous horny crust; cells short curved
projections of the tubes, with simple round
orifices.

Coppinia. Parasitic, massive, hairy ; cells
long, tubular, often curved, arising at irre-
gular distances (generally at the angles of
junction) out of a cellular basis, the aper-
tures of the cells or spores of which are often
themselves covered in by a lid perforated
by a small tubular orifice.

Thuiaria. As Sertularia, but the cells
closely pressed to or imbedded in the surface
of the" stem and branches.

Antennularia. Simple or branched, j ointed,
with slender hair-like whorled branchlets ;
cells small cups on the inner side of the
branchlets ; egg-vesicles seated in the angles.

Plumularia. Simple or branched, feathery ;
cells small, usually in the angles formed by
horny spines on the inner side of the branches;
egg-vesicles scattered.

BIBL. Hincks, Hydr. Zooph. 233.

SETOSEL'LA, Hks.— A genus of Poly-
zoo= Membranipora pt. S. vulnerata, on
very small stones in deep water. (Hincks,
Polyz. 181.)

SHEEP-TICK. See MELOPHTLA.

A species of Trichodectes (sphcerocephalus)
is also found as a louse upon sheep.

SHELL OF ANIMALS. — In this article
we shall notice the various substances com-
prised under the term shell, in its common
acceptation. See PI. 45. figs. 1-16.

Egg-shell. — As an example of the struc-
ture of the egg-shell of birds, we may select
the shell of the egg of the common fowl.

This is lined internally by a loosely ad-
herent layer of a thin yet firm albuminous
membrane, called the membrana putaminis.
It consists of a number of very slender
fibres, interlacing in various directions. In
imperfectly formed or soft eggs, as they are
called, the fibres present thickenings at irre-
gular intervals, resembling, on the whole,
the nuclear fibres of elastic tissue with the

remains of their formative cells still visible.
On macerating the shell in dilute muriatic
acid, an outer layer of this membrane, in-
separably adherent in the natural state to
the inner surface of the shell, may be
detached.

The membrane may be heated to boiling
in solution of potash without undergoing
solution, and is insoluble in acetic acid ; but
it is coloured by Schultze's test.

The substance of the shell consists of nu-
merous masses of secretion, or protoplasts,
impregnated with calcareous matter. In
soft eggs, these form rounded, loosely ad-
herent masses (PI. 45. fig. 12), may easily be
detached from the surface of the egg, and
contain but little calcareous matter; whilst
in the perfect egg they are somewhat angu-
lar from mutual pressure, and abound in
calcareous granules having an imperfectly
radiating arrangement (PI. 45. fig. 13) ; this
is most easily perceived in the inner por-
tions of the shell.

The structure of the shell of the ostrich
presents a curious variety. In a section
parallel to the surface (PI. 45. fig. 14) the
protoplast structure is visible, but the cal-
careous matter is arranged in the form of
triangular plates, often fused together, and
leaving angular interspaces. The perpen-
dicular section is represented in PL 45.
fig. 15. The former section constitutes an
interesting polarizing object.

Tortoise-shell. — This substance is an epi-
dermic formation, structurally resembling
horn, in so far as it consists of epidermic
cells flattened and united into numerous
superimposed plates. The long-continued
action of solution of potash (from twenty-
four to forty-eight hours), and the subse-
quent addition of water, are necessary to
resolve tortoise-shell into its component
cells.

Shells of the Mollusca. — The structure of
these shells varies in the different orders,
&c. of the class ; and a knowledge of the
respective varieties has been used as an aid
to the recognition of fossils, and the de-
termination of the affinities of the genera,
families, &c.

In the bivalve Mollusca, two kinds of
structure may be distinguished, an outer
prismatic or fibrous, and an inner lami-
nated.

The outer prismatic portion consists of
flattened masses or plates of crowded polv-
gonal prisms, placed sometimes perpendi-
cularly, sometimes obliquely to the surface
2Y 2

SHELL.

of the inner layer. These prisms are trans-
parent, and polarize light, possessing a crys-
talline structure, although their forms are
not crystalline but those resulting from
mutual pressure. Transverse sections of
the prismatic structure exhibit a cellular
appearance (PI. 45. figs. 4 & 11 a) ; and a
somewhat similar appearance is presented
by perpendicular sections (figs. 5 and 11 &).
The prisms are pretty easily separable in
the lines of mutual contact, and often form
several superimposed strata. They fre-
quently contain pigment, either uniformly
diffused through their substance, or in gra-
nules. They also sometimes appear trans-
versely striated.

The inner laminated portion, which some-
times constitutes the entire shell, is either
white or presents the brilliant iridescent
tints of nacre or mother-of-pearl. It is
often called the nacreous portion, or nacre,
and when polished forms the mother-of-
pearl of the shops. Under the microscope
it exhibits a number of fine lines or grooves,
running in various directions, and probably
corresponding to the edges or intersections
of the strata or laminae of which this por-
tion of the shell is composed ; and it is to
the interference of light ensuing at the sur-
faces of these grooves that the iridescent
colours are usually owing.

In some shells (Terebratulce) there are
tubes traversing the substance perpendicu-
larly (PI. 45. fig. 7) or obliquely, or forming
branched horizontal channels (fig. 9 a, b) ;
in the latter case they are sometimes con-
nected with rounded cavities (fig. 9 a).

In some Gasteropoda, as Cyprceo, the
outer portion of the shell consists of three
layers of similar prismatic structure, but
with the prisms in each layer in alternately
contrary directions. The same may be seen
in some of the outer layers of oyster-shell,
except that the prisms are nearly horizontal
or slightly oblique. But in the Acephala
generally, the structure corresponds to the
inner portion of that of the Cephalophora.

Shell consists of an organic basis, in which
calcareous matter, principally composed of
carbonate of lime, is deposited; and by
digesting it with dilute muriatic acid, the
latter may be removed, an organic cast of
the original being left. On treating a thin
plate of nacre in this way, Carpenter found
that the iridescent colours remained visible
until the membrane was stretched and the
supposed folds obliterated, when they va-
nished ; hence this author concludes that

[ 692 ] SHELL.

the edges of the folds were the cause of the
interference of light producing the colours.
It appears to us, however, objectionable to
this view, that the same structure and
colour are produced by laminated calcareous
and organic matter artificially formed ; that
they are also present after tne edges of the
folds must have been ground awav, as in
sections; and that the colours, in 'the in-
stance mentioned, might have been those of
a thin plate, and some of the colours of
iridescent shell are known to be those of
thin plates. It may be stated here that
Carpenter considers the lines or striae in
nacre to be produced by the edges of folds
of a single layer of membrane, arranged so
as to He over each other in an imbricated
manner. The same author views the shell
of the Mollusca as corresponding to the
epidermis of the higher animals, calcified.

The outer prismatic layers of shell are
secreted by the borders or margins of the
mantle, whilst the inner laminated portions
arise from the outer surface. The growth
of shell is not uninterrupted or constant, but
periodical; hence the laminated arrange-
ment of its constituents.

In some portions of the shell of the
oyster, &c., the calcareous matter assumes
the form of distinct rhomboidal or hexago-
nal crystals (PI. 45. fig. 10). These appear
to be deposited in the inner laminated por-
tion ; and when detached they leave angular
spaces corresponding to them in form. In
the tooth of the shell of Mya, groups of
radiating prisms are present, forming an
elegant microscopic object.

The prisms existing in the outer portion
of shells have been supposed to represent
cells filled with calcareous matter; they
have also been regarded as consisting of
aggregations of epidermic cells, the trans-
verse striae (in Pinna) corresponding to
thickenings of the cell-membranes where
the layers come into contact ; and the folded
membrane has been compared to a basement
membrane. It is probable, however, that
shell should be regarded as a simple secre-
tion from the mantle, and as corresponding
in structure to egg-shell.

Shell of the Crustacea. — The hard portion
of the integument of the Crustacea, alluded
to at p. 215, possesses a laminated struc-
ture, corresponding to periods of growth,
and giving rise to the appearance of trans-
verse parallel lines in a perpendicular section
(PI. 45. fig. 16). The substance is traversed
by numerous straight, or slightly wavy,

SIAGONTHERIUM.

[ 693 J

SILICA.

very slender tubes (PL 45. fig. 16), resem-
bling those of dentine.

Shell of Echinodennata. — The perforated
structure of the homogeneous basis forming
this substance has been already noticed
(p. 274). In the spines of Echinus, Cidaris,
&c., the calcareous network consists of
slender fibres with large areolas at intervals,
arranged in a somewhat regular pattern, and
traversing a solid homogeneous substance,
which is thus divided into a number of ribs
or pillars. The transverse section of these
is seen in PL 45. figs. 6 & 6 a.

Carpenter regards the calcareous network
as corresponding to the fibrous structure of
the cutis of the higher animals, calcified.
This view does not, however, account for
the intervening substance.

The method of procuring sections of shell
is noticed under PREPARATION.

BIBL. Carpenter, Tr. Brit. Association,
1844 & 1847 ; Ann. N. H. 1843, xii. 376 ;
Gray, Phil. Tr. 1833; Deshayes, Todd's
Cycl. An. Sfc. iv. 556; Bowerbank, Tr.
Micr. Soc. 1844, i. ; Lavalle, Ann. Sc. Nat.
3. vii. ; Siebold, Vergl. An. ; Brewster,
Phil. Tr. 1814, and Optics, 1853; Wood-
ward, Shells ; Williamson, Qu. Mic. Jn. viii.
35 ; Carpenter, The Microscope, 1881, 666.

SIAGONTHE'RICJM, Perty.— A genus
of Enchelia, Body ovate, very minute,
colourless, with an antero-lateral tuft of
reflexed cilia. S. tenue, in bog-water.
(Perty, Inf. 150.)

SI'DA, Baird (Daphnia, auct.). — A genus
of Entomostraca, of the order Cladocera,
and family Daphniidse.

Char. Anterior branch of inferior an-
tennae two-jointed, posterior three-jointed
and with a row of spines at its anterior
margin ; legs six pairs.

8. crystattina (PL 19. fig. 27). The only
species; freshwater.

Daphnella belongs here.

BIBL. Baird, Brit. Entom. 107.

SIDEROLI'NA, Lamk. — Another name
for CALCARINA. (Carpenter, For. 199,
223.)

SIDY'NUM, Sav.— A genus of Tunicate
Mollusca, of the family BOTRYLLID^E.

S. turUnatum. Amber or orange. On
the underside of shelving rocks. (Forbes
and Hanley, Br. Moll. i. 13.)

SIEVE-TUBES.— These are thin-walled,
elongated cells, united end-to-ecd in rows,
the intervening transverse portions, or bases
of the cells, forming perforated sieve-like
plates j the sides next other sieve-tubes are

also sometimes perforated. The protoplasm
of the cells passes through these perfora-
tions, forming minute fibres.

Sieve-tubes are found in the liber of
Dicotyledons, and in the fibro-vascular
bundles of Endogens. They may be most
easily obtained from the stems or leaf-stalks
of Cucurbita pepo, Calamus Rotang, Pota-
mogeton natans, Bignonia speciosa, Vitis
vinifera, &c. Sachs recommends that their
longitudinal sections be treated with so-
lution of iodine until the cell-contents are
rendered brown, and the subsequent addition
of sulphuric acid; this dissolves the cell-
wall and sieve-plates, allowing the slender
protoplasmic filaments to be distinctly seen.

BIBL. Sachs, Sot. 89 ; Henfrey-Masters,
Bot. 487; Wilhelm, Bot. Centralblatt, i.
908, Jn. Micr. Soc. 1881, i. 72.

SILICA. — This inorganic substance is
most abundantly met with in the mineral
kingdom, in the form of earth, sand, or di-
stinct crystals. The crystals belong to the
rhombohedral system, usually forming six-
sided prisms, terminated by six-sided pyra-
mids. The mineral forms are noticed under
AGATE, including chalcedony, and under
ROCKS.

In the animal kingdom, it is met with
especially in the Protozoa, forming the
spicula and elegant siliceous shells so
well-known as microscopic objects, and
which are noticed under the heads of the
classes, genera, &c.

In the vegetable kingdom, silica is a con-
stant constituent of the epidermis of the
Graminacese, the Equisetacese, and certain
Algse, especially the valves of the Diato-
maceae.

Chemically it is distinguished by its inso-
lubility in boiling nitric acid, and its inde-
structibility by a red heat.

If, as Schultze first pointed out, some
sulphuric acid be added to a mixture of
powdered fluor-spar and sand, in a wide-
mouthed flask, with a short tube of mois-
tened blotting-paper in the neck, the fluo-
ride of silicium, which is evolved, is decom-
posed, and silica is deposited in films upon
the paper. If these are washed in distilled
water, dried, and examined under the mi-
croscope, they are found to consist of
minute crystalloid hemispheres of silica,
often pointed, and grouped into plates. The
finer ones present considerable resemblance
to the markings of the finer valves of the
Diatomacese, when so minute as to be only
visible by their lenticular foci or their dif-

SILK.

[ 694 ]

SIPIIONACE^E.

fraction-spectra, whence they were con-
sidered to represent and explain the forma-
tion of the siliceous structure of the valves,
and have been called Schultze's iilms. The
coarser ones have no resemblance whatever
to the coarser markings of the Diatomacese.
Their relation to the valves of the Diato-
maceae has been referred to under DIATO
MACE^E.

Silica has but little action upon pola-
rized light; in fact, Schultze states that the
apparent depolarization is due to refraction.
The selenite-plate will, however, render it
more evident in many instances in which
it is feeble.

BIBL. Works on Chemistry; and Schultze,
Verh. Naturh. Vereins. preuss. Rheinlande,
xx. 1, Qu. Mic. Jn. 1863, iii.

SILK. — This valuable substance is se-
creted in Insects, especially the silkworm,
by two glandular organs, described under
INSECTS, Spinning Organs.

The fibres of which it is composed are
cylindrical or somewhat flattened, solid,
tolerably highly refractive, and free from
structural markings of any kind.

Chemically, silk consists of a proper silk-
cylinder, consisting of fibroine and forming
the principal part of the fibres, surrounded
by a coat of albumen, upon which is a layer
of gelatine. The fibres also contain a small
quantity of fat and colouring-matter.

Fibres of silk may easily be distinguished
from those of linen or cotton by the appli-
cation of Millon's or Schultze's test, both of
which colour the silk, but neither of them
the linen or cotton. The test for cellulose
is equally applicable to the same purpose.

SIMULTANEOUS BUNDLES. See
VASCULAR TISSUE.

SIPHOCORY'NE, Buckt— A genus of
Aphides. (Buckton, Aphid, ii.)

SIPHONA'CE^E.— A family of Confer-
void Algse, either marine, freshwater, or
growing on damp ground ; characterized by
the individual fronds being composed of
large branched cells, the contents of which
expelled in various forms serve for the
reproduction. The fronds mostly have a
more or less compound character, either
from regular ramification, or by a kind of
stoloniferous multiplication at the base of
the cells ; and in Hydrodictyon, which seems
best placed in this family, the cells are
always connected together by their extre-
mities, so as to form a net-like frond. In
the majority of the genera the cell -contents
are green. The modes of reproduction

exhibit considerable diversity, and are pro-
bably still imperfectly known in most of the
genera. Codium and Bryopsis are repro-
duced by the discharge of the contents of
certain cells in the form of numerous small
ciliated zoospores. Vaucheria is increased
by large elliptical solitary zoospores, covered
with vibratile cilia ; in Hydrodictyon the
cell-contents are converted into a multitude
of ciliated zoospores, which unite to form a
new net or frond before leaving the parent
cell ; while in Botrydium the cell-contents
are said to he discharged in the condition
of motionless gonidia ; but we imagine this
point is not quite certain. In addition to
the gonidial reproduction, spores have been
discovered in Vaucheria^ and will probably
be found in the rest. In Vaucheria they
occur in special branch-cells ; here, however,
accompanied by antheridial cells, which pro-
duce spermatozoids, fertilizing the sporan-
gial cell. Spores have not yet been ob-
served in the other genera; but it is to be
expected that they will be found in them
also. More particular details on the very
interesting genera of this somewhat hetero-
geneous family will be found under their
respective heads. British genera :

Codium. Filaments green, branched,
closely interwoven into a spongiform frond,
producing biciliated zoospores in sporangia!
cells borne on the sides of the erect clavate
branches; marine.

Bryopsis. Filaments green, free, pin-
nately branched, producing two- or fuiir-
ciliated zoospores in the extremities of the
branches ; marine.

Vaucheria. Filaments green, more or
less branched, continuous, producing in
their apices large solitary zoospores covered
with cilia ; also bearing lateral globose spo-
rangial cells and hook-like autheridial cells
or horns; marine or freshwater, and still
more commonly on muddy ground, damp
garden-pots, &c.

Botrydium. Frond a spherical green
vesicle seated on a ramified filamentous
base, the cavity of the whole continuous;
the ramified base producing new vesicles,
sporanges, by stoloniferous growth. Mul-
tiplied by the granular contents of the vesi-
cle discharged by a rupture at the summit.
On damp, mostly clayey ground subject to
floods.

Hydrodictyon. Frond a green bag-like
net, with usually pentagonal open meshes,
formed of cylindrical cel-ls connected by
their ends. Keproduced by ciliated zoo-

SIPIIONIXA.

[ 695 ]

SKIN

spores formed in the u link "-cells, uniting
toovther and forming a perfect miniature
net before escaping from the parent cell.

See also Pv nur\i.

SIPHONI'NA, Keuss.— A low form of
Planorbulina, having open-mouthed tubes
leading off the pseudopods from the cham-
bers, and large-necked septal orifices. Re-
cent and fossil in the Mediterranean area.
(Parker and Jones, Ann. N. If. 3. xi. 94.)

SIPHONOPH'ORA, Koch.— A genus of
Aphidie. Species numerous, on a variety of
plants. S. rosce = Aphis r. (Buckton, Aphi-
d<e, i. 104.)

SH'HONOPH'ORA.— An Order of Hy-
dro-medusae ; the oceanic Hydrozoa. (Hux-
ley, Phil. Tr. 1849.)

SI PHONOS 'TOM A (Parasite, orPrecilo-
poda). — An Order of Crustacea.

Char. Body often almost entirely enclosed
in a buckler, consisting generally of one,
sometimes of two pieces ; mouth suctorial ;
legs formed for walking or prehension, or
partly branchiferous and fitted for swim-
ming. Parasitic upon fishes, &c.

These animals (PL 19. figs. 7, 23, 24, 36,
and PL 20. fig. 1), which often present the
most extraordinary forms, are found mostly
affixed to the gills of fishes by means of
hooks, arms, or suckers, arising from or
consisting of modified foot-jaws. In some,
the cephalothorax is distinct from the abdo-
men, and the head is more or less distinct
from the thorax ; whilst in others the body
presents more of a worm-like form, is occa-
sionally ringed or segmented, and sometimes
exhibits simple or branched lateral lobes or
processes. The antennas are mostly rudi-
mentary. Flattened elytriform dorsal ap-
pendages are sometimes present. The ros-
trum is conical, tubular, and furnished with
two setaceous or styliform mandibles. The
alimentary canal is straight, without a
gastric expansion, and its orifices at the two
ends of the body. In some, branchial plates
form the respiratory organs; but in most
the same office is performed by the skin.

The sexes are distinct, although they are
not known in all the species. The males
are smaller than the females. The ova are
often attached to the lower part of the body
of the females, either contained in external
ovaries, or simply glued together by the
secretion from a special gland, and forming
long, cylindrical, straight or convolute ap-
pendages. The young animals have but few
legs, swim freely, and frequently resemble
the young of Cyclops.

BIBL. Baird, Br. Entomostr. ; M.-Ed-
wards, Hist. Nat. Crust, iu.; Siebold, Very I.
An.

SIROC'ROCIS, Kiitz. — Probably the
mycelium of a fungus.

BIBL. Kiitzing, Sp. Ah/, p. 153.

SI ROGO'N I UM, K iitzing.— 8. notabile =
Mesocat-pus notabilis, Hass. ; S. sticticum =
Spirogyra (Zt/ynema, Hassall) stictica; S.
breviarticulatum = Spirogyra curvata.

SIROSl'PHON, Kiitz.— A genus of Os-
cillatoriaceae (Confervoid Algae), which
should perhaps have been placed under the
older name of Hassallia. This genus is
principally distinguished by the solitary
branches passing off from the sides of the
rather rigid filaments, the branches arising
from longitudinal division and lateral growth
of interstitial cells. The plants are black,
and found on wet moors, rocks, &c. Two
species seem to be established — S. ocellata
(PI. 8. fig. 12), and S. compacta ; Leigh-
ton places the latter among the Lichens ;
others appear doubtful.

BIBL. Hassall, Alg. 231; Kiitzing, Sp.
Alg. 315, and Tab. Pkyc. ; Leighton, Lich.
Fl 9 ; Rabenhorst, Alg. ii. 285.

SKELETON LARVA.— The larva of
Corethra plumicornis, a dipterous insect, of
the family Tipulidae.

It is very transparent, and shows well the
internal structure.

BIBL. Westwood, Insects, ii. 515 ; Prit-
chard, Micr. lllustr. 50.

SKELETONS 'MA, Grev.— A genus of
Diatomaceae.

& Barbadense, in the Barbadoes deposit.
(Grev. Micr. Tr. 1865, 43.)

SKIN OB INTEGUMENT OF ANIMALS.

Three parts are distinguishable in the skin :
an outer or cellular, forming the epidermis ;
an inner fibrous, or cutis vera ; and an inter-
nal or subjacent, known as the subcutaneous
cellular tissue. The two former constitute
the skin proper.

The cutis vera or corium (fig. 641 c) con-
sists of connective and elastic tissue, with
fat-cells, blood-vessels, nerves, absorbents,
and unstriated muscular fibres. The fibres
of the connective tissue are variously inter-
laced and united into interwoven bundles,
forming a tolerably dense and firm tissue,
with small areolas, and sometimes presenting
laminae. The elastic, tissue is less abundant
than the connective, and consists of net-
works of finer or coarser fibres.

The outer surface of the cutis gives off
a number of conical processes or papillae

SKIN.

[ 696 ]

SKIN.

(fig. 641 e)t which are frequently bifid,
lobed, or arise several from a common base.
In many parts of the skin they are arranged
in more or less regular rows.

In certain papillae, the connective tissue
is often homogeneous, especially in the me-
dian portion, where it forms an oval trans-
parent body (fig. 642 a), surrounded by a
layer of imperfectly developed elastic tissue,
consisting of spindle-shaped cells and fibres
taking a horizontal or circular direction,
and giving the oval body a transversely
striated or laminated appearance. These
are called tactile corpuscles, and are most
abundant at the ends of the fingers and in
the lips. See also PACINIAN CORPUSCLES.
The cutaneous papillae are traversed by the
terminal loops of the capillaries (tig. 642 d)
and nerves (tig. 642 c).

The cutis is continuous beneath with the
subcutaneous cellular or properly areolar
tissue (fig. 641 d), which is of a much more
lax texture than the cutis, presenting large

Fig. 641.

areolae filled in most but not all places with
fatty tissue (tig. 641 /).

The cutis is everywhere covered externally
with a thin membrane, and this by the epi-
dermis, which is a semitransparent coat,
containing neither vessels nor nerves, mould-
ed as it were upon the surface (fig. 643)
and filling up the intervals between the pa-
pillae (fig. 644). The variously arranged lines
seen upon its outer surface are depressions
corresponding to those existing upon the
cutis between its rows or groups of papillae.

The epidermis consists entirely of nu-
cleated cells ; and two distinct layers are
recognized in it (tig. 643), an inner forming
the rete mucosum (tig. 643 c), and an outer
or cuticle (tig. 643 d). The rete mucosum
is softer than the cuticle, and is fre-
quently of a brownish colour, from its
cells, especially the deepest, containing gra-
nules of pigment. These cells are not all of
the same form, those immediately applied
to the cutis being somewhat elongated and

Fig. 642.

Fig. 641. Perpendicular section of the skin of the under surface of the end of the thumb, through three furrows,
a, cuticle; 6, rete mucosum; c, cutis vera ; d, upper part of subcutaneous tissue; e, papiTse of the cuds ; f, fatty
tissue ; g, sudoriparous glands ; h, sudoriparous ducts ; i, orifice of the latter. Magnified 20 diameters.

Fig. 642. Papillae from the skin of the under part of the end of the finger, a, axial body ; b, nerve ; c, its ter-
minal loop ; d, d, loops of capillary blood-vessels. Magnified 250 diameters.

SKIN.

[ 607 ]

arranged perpendicularly upon its surface
(tig. 643 b). The next fire so;nnvhat cubi-
cal; and their surface often exhibits fiat
->s or teeth, forming the so-called
" prickle-cells." The cells of the next rows
are polygonal, and contain one or more
nuclei ; "tliey have a distinct cell-wall, and
some have hair-like processes.

The cells of the cuticle are colourless,
tl.itt 'tied, often wrinkled or folded, and
correspond to the pavement epithelium of
the mucous membranes. Between the epi-
dermis and the cutis is situated a basement
membrane, which is easily distinguishable.

In preparing the skin, it may be hardened
by a mixture of chromic acid and alcohol,
and stained with picro-carmiue. By keep-
ing a portion of skin in a digestive liquid, as
pepsine and dilute muriatic acid, the con-
ne tive tissue becomes transparent, and ex-
hibits clearly the muscular and elastic fibres.

In the examination of the skin, sections
must be made with Valentin's knife, and
these treated with acetic acid, solution of
potash, dilute nitric acid, &c. The blood-
vessels are well seen, as regards general

SKIX.
Fig. 643.

Perpendicular section of the skin of the Negro, a,
papillae of the cutis; 6, deepest and most intensely
coloured layer of elongated perpendicular cells of the
rete mucosum ; c, upper layer of the rete ; d, cuticle.

Magnified 350 diameters.

Fig. G44.

Under surface of the epidermis of the palm of the hand, a, ridges corresponding to
d^ .of the cutis; b, ridges corresponding to the furrows between the rowsof papilla
, their broad insertions in the epidermis; e, depressions corresponding to the papilla.'.

Magnified about 20 diameters.

SLATE.

[ 698 ]

SNOW.

arrangement, in injected preparations, some
of which, as those of the pulp of the finger,
form very beautiful objects. The epidermis
is easily separated by maceration.

Fig. 645.

Section of the skin of the heel parallel to the surface,
through one entire ridge of the skin and part of two
others ; showing the arrangement of the papillae in rows
corresponding to the ridges of the cutis. a, cuticle
between the ridges; 6, rete mucosum; c, papillae; d,
portion of the rete mucosum between papillae arising
from a common base ; e, sudoriparous ducts.
Magnified 60 diameters.

The integument of animals is noticed
under the respective heads of the classes.

It must be remarked that the terms epi-
dermis and cuticle are generally used syno-
nymously.

BIBL. Kolliker, Mik. An. i., and Gewebe-
lehre; Todd and Bowman, Phys. An.;
Meissner, Beitr. z. An. u. Phys. d. Haut,
1863 ; Biesiadecki, Strieker's Hist.

SLATE. See ROCKS.

SMARTS, or SMARIDIA, Latr.— A genus
of Acarina, family Trombidina.

Char. Palpi slender, inserted upon a re-
tractile rostrum ; mandibles sword-shaped ;
body entire, narrow anteriority ; coxae stout,
distant, the anterior articulated to a fixed
eminence upon the body ; legs palpatorial,
used also as palpi, the anterior longest.

S. papillosa (PL 6. fig. 36 ; a, mandible).
Body vermilion-coloured, broader in front,
depressed, covered with short cylindrical
papillae rounded at the end. Fusiform
scales replace the papilla* upon the legs,
palpi, and rostrum.

Found upon the trunks of trees, and in moss.

Several other species are found in moss,
upon fallen leaves, and on the debris left
after inundations.

In S. expalpis, Koch, there are no palpi.

BIBL. Duges, Ann. Sc. N. 2. i. 16 & 34 ;
Grervais, Walckenaer's Apt. iii. 173; Murray,
EC. Ent. 149.

SMIT'TIA, Hincks.— A genus of Escha-
ridae (Cheilostomatous Polyzoa),=Ze/>ra/e'a
sp., with the secondary orifice elevated, pro-
duced, and channelled in front. 7 species.
(Hincks, Polyzoa, 340.)

SMUT. See UBEDO.

SNAILS, WATER-.— Most microscopic
observeis, ever anxious to determine the
unknown cause of the curious circulation
or rotation (ROTATION) taking place in cer-
tain water-plants, as Vallisneria, Anacharis^
&c., keep these growing in large glass ves-
sels, as confectioners' jars, or Vivaria.
These plants, and the sides of the vessels,
are however very apt to become overgrown
and obscured by Coufervoid Algae (as (Edo-
gonium), Palmellaceae, &c., which may be
prevented by keeping water-snails in the
water, as species of Limnceus, Physa, By-
thinia, Planorbis, &c. The latter are best
for this purpose (the shell is flat-spiral).
If Desmidiacese, Diatomaceae, Infusoria, &c.
are to be preserved, the snails must be care-
fully excluded, because many of these are
consumed by them, and will not live, as the
bottom of the vessels soon becomes covered,
when snails are kept, with a load of excre-
ment. The characters of the snails are too
long to be given here. The gelatinous masses
of ova are found adhering to water-plants.

See the Bibl. of MOLLUSCA.

SNOW. — The various forms presented by
ice or crystallized water in the form of snow
constitute beautiful although fugitive mi-
croscopic objects.

The crystals belong to the rhombohedric
or hexagonal system. Several hundreds of
forms have been observed, and many of
them figured. Among them may be men-
tioned hexagonal or dodecahedral plates ;
hexagonal prisms, single, arranged in a
stellate form, or terminated by rectangularly
placed plates or secondary groups of needles;
hexagonal pyramids, &c. The angles of
these forms frequently constitute secondary
centres, around which other similar or dis-
similar forms are aggregated. By some
authors these forms are regarded as skeleton
crystals.

'See also RED SNOW.

BIBL. Scoresby, Arctic Regions; Kamtz,

SODA.

[ 099 ]

SPECTROSCOPE.

Meteorolorjie ; Glaisher, Mic. Jn. 1855, iii. ;
Kmmann, Mineraloyie.

SODA. — Kolliker recommends a solution
of caustic soda, in preference to potash, for
the resolution of some of the tissues into
their component elements. We have been
unable to detect any marked difference be-
tween the action of these two solutions ;
and the former has the disadvantage of
lifting the stopper from the bottle by the
crystallization of the carbonate formed; so
that it is with difficulty preserved.

PI. 10. fig. 15 represents the crystals of
oxalate of soda; and fig. 19 those of the
nitrate (UREA).

SODIUM, CHLORIDE OF, or common
salt. — The crystals of this salt belong to
the regular system. The most common
form is the cube terminated by quadrangu-
lar pyramids or quadrangular pyramidal
depressions, rectangular tables, &c. Schmidt
endeavours to show that the primary form
of the crystals is the octahedron, and that
the cubes are twin octahedra. The crystals
do not polarize light. (Schmidt, Entwurf
ein. allg. Untersuch. 90 ; and the Bibl. of
CHEMISTRY.)

SCEMMERING, MIRROR OF.— INTRO-
DUCTION, p. xxii.

SOLENOPH'RYA, Cl. & Lach. — A
genus of Acinetiua.

Char. Sessile and with a membranous
lorica, tentacles simple, in distinct tufts. On
roots of Lemna. (Clap, et Lach. Inf. 389.)

SO'LIUM, Heib.— A genus of Biddul-
phiese (Diatomacese). (Rabenh. Alg. i. 319.)

SOLORI'NA, Ach.— A genus of Phyl-
lodei (Lichenaceous Lichens). 4 species, in
mountainous districts. (Leighton, Licli.
Fl. 106.)

SORAS'TRUM, Kiitz.— A genus of Des-
midiacese.

Char. Frond globular, composed of com-
pressed radiating cuneate cells, bifid at the
apex.

S. spinosum (PI. 3. fig. 22), in stagnant
turf-pools.

BIBL. Kiitzing, Sp. Alg. 195 ; Rabenht.
Ah/, iii. 81 ; Carter, Ann. N. H. 1869.

SORITES, Ehr. See AMPHISORUS and
ORBITOLITES.

SOROSPH^E'RA, Br. — A free, Are-
naceous Foraminifer, with numerous aub-
globular thin-walled chambers (1-5" diam.),
loosely attached, and irregularly crowded.
S. confusa, in the Atlantic and Pacific,
900-2900 fathoms. (Brady, Qu. Mic. Jn.
n. s. xix. 9 j

SOROS 'PORA, Hass.— A genus of Pal-
mellacece (Confervoid Algae) noc clearly
distinguished from Gloeocapsa and Proto-
coccus. (Hassall, Alyce, 309.)

SOROTHE'LIA, Korb.— A genus of Mi-
crolichens, parasitic on the thallus of Plyc-
tis argena. Spores 8, 2-locular, brown.
(Lindsay, Qu.°M. J. 1869, 343.)

SO'RUS.— The name applied to the ag-
gregation of sporanges of the FERNS; some-
times applied also to the groups of spores in
the Florideous Algas.

SPATHID'IUM, l\\).=Leucophrysvt.
SPATHULA'RIA, P.— A genus of Dis-
cornycetes (Ascomycetous Fungi), with a
fertile head running down the stem on either
side. S. flavida is one of our prettiest
Fungi when in perfection.

BIBL. Grev. t. 165; Berk. Outl. t. 21.
fig. 7; Cooke, Handb. 661.

SPECTROSCOPE, OR MICROSPECTRO-
SCOPE. — The spectrum-analysis of coloured
microscopic objects may be effected by
means of one or more prisms in connexion
with the simple or compound microscope.
The prism, or combination of prisms, may
be placed, either beneath the achromatic
condenser, in the body of the microscope, or
in the eyepiece ; and this last arrangement
is usually adopted. Sorby and Browning
have perfected the microscopic eyepiece.

Above the eye-glass of the eyepiece,
which is made achromatic and capable of
focal adjustment for rays of different refran-
gibility, is placed a tube containing five
1 prisms, two of flint glass interposed between
I three of crown glass in such manner that
j the emergent rays which have been separa-
j ted by the dispersive action of the flint-glass
1 prisms are parallel to the rays which enter
the combination. Below the eye-glass, in
the place of the ordinary stop, is a diaphragm
with a narrow slit, which limits the admis-
sion of light. Objects placed on the stage
of the microscope, provided they transmit a
sufficient quantity of light, may then be
examined, and their spectra observed. If it
is desired to compare their spectra with any
other, provision is made for tne formation or*
a second spectrum, by the insertion of a
right-angled prism which covers one half of
the above-mentioned slit and reflects up-
j wards the light transmitted through an
aperture in the side of the eyepiece. For
! the production of the ordinary spectrum,
light is reflected into this aperture from a
1 small mirror carried at the side ; while for
' the production of the spectrum of any sub-

SPERMATIA.

[ 700 J

SPERMATOZOA.

stance through which the light reflected
from the mirror can be transmitted, it is
only necessary to place the slide carrying
the section or crystalline film or the tube
containing the solution in the frame adapted
to receive it. In either case this second
spectrum is seen by the eye of the observer
alongside of that produced by the object
viewed through the body of the microscope,
so that the two can be exactly compared.
Some care is requisite in the arrangement
and number of the prisms according to the
amount of dispersive power required.

Crookes has devised a modification of this
apparatus, in which the prisms and slit can
be withdrawn and replaced without remo-
ving the eyepiece.

The spectroscope is of the utmost value
in microscopic, as in other researches ; but
its study is very difficult, and we have no
space to enter into its minute details.

BIBL. Sorby, Qu. Jn. Sc. ii. 198, Proc.
Roy. Soc. xv. 433, Mn. Mic. Jn. xiii. 198
(blood-stains), and Beetle's How, &c. 269 j
Lockyer, Phil. Trans. 1874, 481, and Spec-
troscope ; Browning, Spectroscope ; Schellen,
Spectroscope-, Proctor, Spectroscope; Hug-
gins, Tr. Mic. Soc. 1865 ; Crookes, M. M.
Jn. 1869, 371; Suffolk, Spectr. Analys.;
Vierordt, Sp. Anal., quant., 1876: Ward,
Jn. M. Soc. 1878, i. 326 (new spectroscope);
Palmer, Mn. M. J. xvi. 277 (measurement) ;
McMunn, Spectr. in. Med. 1881.

SPERMATIA.— The minute corpuscles
supposed to represent spermatozoids in the
LICHENS (PI. 37. figs. 3, 15, 16) and FUNGI
(PL 26. figs. 2, 3, 4).

SPERMATOZO'A OF ANIMALS.— The
form of the spermatozoa varies in dif-
ferent animals (PI. 50) ; but they usually
consist of a rounded or oval body or head,
to one end of which is appended a move-
able filament. This is their form in man
(fig. 25), and the Mammalia generally (figs.
26-28) ; the former exhibit an undulating
membrane (Gibbes). In Birds, the body is
sometimes cylindrical, sometimes spiral or
presenting a zigzag outline (figs. 29-31).

In Reptiles, the body is usually cylindri-
cal and straight ^fig. 33), sometimes spiral;
they are very large in Amphiuma ; but in
some of them, the straight or slightly undu-
lating terminal filament is surrounded by a
spiral fibre or Undulating Membrane (fig. 17).
In some instances, the so-called undulating
membrane consists of adherent portions of
the formative protoplasm.

In Fishes, the spermatozoa are usually

very small, and the body rounded, al-
though in some the body is spiral (fig.
34).

In the Invertebrata, a distinct body and
terminal filament are present in some ;
while in others each spermatozoon forms a
simple filament tapering at the ends (fig. 32).
In some instances, the body seems to exist
as a short cylinder or rod ; in others, the
spermatozoa are represented by simple cells,
or cells with radiating processes.

The development of the spermatozoa is not
agreed upon. In the higher animals, the
protoplasm of the peripheral cells of the
seminal canals grows inwards into finger-
like processes, called spermatoblasts. In
each of these, a nucleus is formed, constitu-
ting the head of the spermatozoon, the pro-
toplasm at the end of the process growing
into the filament, so that each sperniato-
blast produces 8 or 10 speimatozoa. Ac-
cording to Kolliker, they are developed
within the epithelial cells of the tubuli,
nuclei or globules arising within these, in
each of which a spermatozoon is found
coiled up (PI. 50. figs. 35, 36). In some
animals, the spermatozoa are formed in
bundles, the bodies and filaments lying
parallel with and opposite each other
(fig. 37).

Most spermatozoa exhibit active move-
ments, produced by the action of the fila-
ment, whence they were formerly con-
sidered independent animals ; but these
movements are comparable with those of
the ciliated zoospores of the Algse, or the
ciliated epithelium of animals; they are
increased by the addition of caustic potash.

In some animals, tubular sheaths are
secreted around the masses of spermatozoa
while contained in the seminal apparatus,
and called spermatophores. These, when
discharged from the organ, are fixed by the
male to the posterior end of the body of the
female by means of a glutinous secretion.

The spermatozoa are the essential fertili-
zing elements of the liquid in which they are
contained.

Spermatozoa may be best examined and
preserved by washing them with distilled
water, and drying them upon a slide.

BIBL. Kolliker, Mik. An. ii. ; id. Beitr. z.
Kenntn. d. Geschlechts. d. wirb. Thiere;
Czermak, Sieb. u. KolL Zeit. ii. ; Wagner,
Todd's Cycl. iv., art. Semen ; id. Physiology,
by Willis ; Leuckart, Wagner's Handwb'rt.
d . Phys. iv. 819 ; Beneden, An. Comp. ;
Owsiannikofi^ Mn. M. Jn. i. 312; Lankester,

SPERM ATOZOIDS.

[ 701 ]

SPH^RIA.

Qn. Mic. Jn, 1871; St. George, Strieker's
Hist. ii. 141, and the Bill. ; Klein, Hist. ;
Einer, Phys. Med. Ges. Wiirtaburg, vi. 93 ;
Johnston, M. Mic. Jn. xvi. 61 (Amphittmo).

SPERMATOZO'IDS, or ANTHERO-
ZO'IDS.— The terms applied to the struc-
tures produced in the antheridia of the
Cryptogarnia, regarded as analogous to the
spermatozoa of animals, and as the agents of
fertilization of the germ-cell. In the Mar-
sileacese, Lycopodiaceae, Equisetaceae, Ferns
(PI. 40. fig. 34), Mosses (fig. 33), Hepaticaa
(fig. 32), and 'Characece (tig. 31), they are
ciliated spirally-coiled filaments, exhibiting
very active spontaneous motion. In the
Fucoid Algae, they are globular cells bearing
two unequal cilia moving actively. In the
Florideae they are minute globular cells (PL
4. fig. 12 a), and neither cilia nor movement
have been demonstrated. In the Lichens
and Fungi the spermatia (PL 26. fig. 4; PL
27. fig. 23; PL 37. fig. 15) appear to represent
the spermatozoids of the other classes, and
they seem to be devoid of spontaneous move-
ment. The details respecting these bodies
are given under their respective classes.

BIBL. Thuret, Ann. Sc. Nat 3. xiv. 214,
and xvi. 5 ; Schacht, Sperm, im Pflanz.
1864, & Qu. Mic. Jn. 1805.

SPERMOGO'NIA.— The supposed an-
tlieridial structures of LICHENS (PL 37.
figs. 2, 13, 15) and FUNGI (PL 26. figs. 1
and 4).

SPERMOSI'RA, Kiitzing.— A genus of
Nostochaceae, growing in salt marshes,
containing two British species ; known
from the other genera by the disk-shaped
or lenticular cells; but the filaments are
liable to be mistaken for a Nostoc in the
young state.

Spermosira litorea, Kiitz. (PL 3. fig. 20).
Filaments 1-3600" thick, straight] sh, aeru-
ginous ; ordirary cells confluent, very short ;
sporan<?ial cells at first green, depressed-
spheroidal, 1-3000" in diameter, granular,
fuscous when mature ; vesicular cells trans-
versely elliptical, not wider than the ordinary
cells. " In muddy brackish ditches.

S. Harveyana, Thwaites. Filaments
much curved ; cells nearly as long as broad ;
sporangial cells exactly spherical, almost
twice the diameter of "the ordinary cells ;
vesicular cells subquadrate, rather longer
than wide, about as wide as the ordinary
cells. In muddy brackish ditches.

BIBL. Harvey, Brit. Alaer, 233, and Phyc.
Brit. ; Kiitzing, Tab. Phyc. i. ; Rabenhorst,
Alfj. ii. 185.

SPHACELA'RIA, Lyngb.— A genus of
Ectocarpaceae (Fucoid Algae), containing a
number of species, two of which, S. scoparia
and & cirrhosa, are common. They have
jointed,rigid, distichously branched, feathery
filamentous fronds, of an olive colour, a few
inches high, and are especially characterized
by the sphacelfs formed at the ends of the
branches. They multiply by zoospores pro-
duced iminilocular or plurilocular sporangia.
The propagula are produced on the lateral
branches, and are connected by a cell which
may produce several of them. Each con-
sists of a pedicel of three rays and of a
multicellular pair. The rays and pedicel
produce when they come into contact with
those of another Alga, short shields like a
prothallus, of which the peripheral cells
may produce new plants.

BJBL. Harvey, Mar. Alg. 55; Janczewski,
Mem. Soc. Nat. de Cferbourff, xvi. 337.

SPK/E'RIA, Hall.— A genus of Pyreno-
mycetes (Ascomycetous Fungi), now some-
what reduced from its ancient limits, but
still containing a vast number of species,
which it is impossible to treat satisfactorily
within our limits. The forms vary chiefly
in regard to the perithecia, which are some-
times only covered by a veil, and hence
appear superficial on the matrix, while in
other cases they are imbedded in the matrix

Fig. 646.

Bphaeria quaternafau

Three groups growing on a piece of beech wood.
Magnified 20 diameters.

(PL 26. fig. 25), only evident externally by
the black papilla, which is permanent,
becoming indurated, and opening by a pore
to discharge the spores in a fine powder.
Many of the immersed kinds are only evi-
dent externally as minute black points or
dots upon the surface of the leaf, stem, &c.
which they infest ; others are exposed freely
when mature, breaking out from beneath the
epidermis. Sometimes they are solitary,
sometimes associated in small or large
numbers, distinct or confluent. S. quaternata
(fig. 646) is an example of the occurrence
of free perithecia grouped together, mostly
in fours; being decumbent, their ostioles
are collected together, and they perforate
the bark by a little black rugged tubercle.

SPELER1A.

[ 702 ]

SPH^RIACEI.

This is common on beech trees. S. con-
vergent (figs. 647, 648) is an analogous form.
S. elongata (figs. 655-657) affords an example
of those species which are at first immersed
and adnate, and finally burst forth and
become nearly free.

Fig. 647.

Fig. 648.

Sphaeria convergens.
Magnified 20 diameters.

Fig. 649.

i

Sphseria verrucosa.
Magnified 20 diameters.

For species now separated from this genus
see CLAVICEPS, HYPOXYLON, XYLARIA,
HYPOCREA, and NECTRIA.

Certain points of great interest have lately
been ascertained respecting this genus and
its allies, which are mentioned under the
heads of the family and other genera, namely
the coincidence and evident connexion be-
tween true species of Sphceria and various
Coniomycetous Fungi ; for just as Melasmia
is a precursory form of Dotliidea, Tubercu-
laria of Nectria, &c., Cytispora, Septoria,
and other forms precede Sphceria, and many
distinct stylosporous forms are associated,
usually described as belonging to distinct
genera, such as Stilbospora, Sporocadus,
Sphceropsis, &c. Thus these plants seem to
produce three kinds of reproductive organs,
as is now known to be the case with the
Uredinei, viz. : — (1) a form analogous to the
spermogonia of the Lichens (in Sphceria
represented by Cytispora, &c.) ; (2) an
ascophorous fruit, the perithecium of the
true Sphceria ; and (3) a stylosporous fruit,
representing the genera Stilbospora, Sporo-
cadus, &c.

S. Laburni has been found by Tulasne to
exhibit all these stages, namely perithecia
containing asci surrounding a cytispore,
with other conceptacles on the same stroma
resembling the perithecia, but lined with
stylospores instead of asci. Berkeley and

Broome also describe the existence of the
perithecia of Sphceria inqulnam and the
conceptacles of Stilbospora . macrosperma on
the same stroma (PI. 26. figs. 25-28).

It is stated by Tulasne that the spermatia
of the cytisporous forms may be contempo-
raneous with the stylospores brbasidiospores,
but they always precede the ascospores in
their development ; hence there is ground
for supposing that they represent the sper-
matozoids of the higher Cryptogamia.
With regard to the relations of the stylo-
spores, it is possible that they are merely
modifications of the ascospores ; but it
would appear probable that they must be
regarded as real gonidial structures, for
which it may be desirable to retain Fries's
name of conidia, just as that of tetraspores
is retained among the Florideous Algae.
Attention should be directed here to the
complete correspondence between the series
of forms of these genera and those of the
UREDINEI, where, as in PUCCINIA, we
have the spermogonium (cytispore), the
uredo (stylosporous fruit), and the perfect
fruit, (perithecium). See also CONIOMY-
CETES.

Currey has published some extensive
observations on the spores of the Sphcerice.

BIBL. Berk. JBr. Fl ii. pt. 2. 232 ; Ann.
N. H. i. 205, vi. 360, 2. v. 374, vii. 186;
Hook. Jn. Hot. iii. 319 ; Fries, Sum. Veget.
388, Syst. Mycol ii, 319; Tulasne, Ann.
So. N. 3. xv. 375 (Ann. N. H. 2. viii. 117),
4. v. 108, viii. 35; Currey, Mic. Jn. 1855,
iii. 263, Linn. Tr. xxii. 257.

SPH^ERIACEI— A family of Ascomy-
cetous Fungi, containing a vast number of
parasitic plants, mostly of minute dimen-
sions, growing upon leaves, stems, bark,
wood, &c., and sometimes on the bodies of
insects. The essential distinctive character
lies in the globular, ovate, or flask-shaped
conceptacle or perithecium^ containing asci,
which ultimately opens by a pore at its
summit to discharge the spores. These
perithecia occur either solitary or in groups
on an indistinct matrix, growing out from
the epidermis of leaves, &c. (Sphceria) ; or
they are immersed in a tubercular stroma
(Nectria) , while in the larger forms the
stroma becomes developed into an erect
clavate or bushy structure, of fleshy or
horny consistency, the perithecia being
imbedded in the superficial layer of this,
and opening by pores on the surface. Much
remains to be done in reference to the
history of this family, not merely on account

SPHJERIACEI.

[ 703 ]

SPH/ERIACEI.

of the polymorphous characters of the asco-
phorous forms, but from the circumstance
tint it has recently been shown, as was sus-
pected before, that there is a relationship
existing between them and the supposed
genera of Coniomycetous Fungi of similar
habit. These last are in fact mostly forms
of Sphaeriaceous Fungi, as is indicated
under the heads CONIOMYCETES, ASCOMY-

CETES, DOTHIDEA, SPH^RIA, CYTISPORA,

SEPTORIA. Our treatment of this family
is very imperfect, the knowledge of them
being confined to few persons, and much of
it lying scattered in fragments. British
genera :

* Stroma erect.

Clauiceps. Stroma simple, clavate ; peri-
thrciii superficial, in a distinct layer at the
summit of the clavate stroma ; asci tubular ;
spores very long, multiseptate.

Xyhiria. Stroma simple or branched ;
perithecia spread all over, often wanting at
the summit, black ; asci eight-spored ; spores
uniseptate.

Fig. 650.

Fig. 651.

Fig. 652.

Xylaria guianensis.
Fig. 650. A stroma. Nat. size.
Fig. 651. Vertical section of the same. Nat. size.
Fig. 652. Section of a perithecium. Magnified 10 dia-
meters.

Thamnomyces. Stroma branched, shrubby,
or stalk-like ; perithecia formed from the
stroma, more or less naked ; asci tubular ;
spores simple, ovate.

** Stroma between erect and horizontal.
Poronia. Stroma cup-shaped, stipitate

or sessile, margined ; perithecia in the disk,
superficial; ostioleaeven slightly prominent.

*** Stroma horizontal.

Hypocrea. Stroma distinct from the
matrix, tubercular; perithecia immersed;
asci filiform ; spores simple or uniseptate.

Hypoxylon. Stroma distinct from the
matrix, at first covered with a floccose
mealy veil; perithecia black; asci linear-
clavate; spores subseptate, expelled in a
cloud of black powder.

Fig. 653. Fig. 654.

Xylaria grammica.
Fig. 653. Natural size
Fig. 654. Horizontal section. Magnified 5 diameters.

Diatrype. Strorna partly formed from
the matrix, not distinct ; perithecia deep-
seated, produced into a long neck, and
frequently a beak; spores simple and pel-
lucid.

Dothidea. Perithecia undistinguishable
from the stroma ; asci collected into a glo-
bose nucleus with a neck above, leading to
an ostiolate papilla.

Stroma wanting ; the perthecia often
seated on a tuberculous, crustaceous, bys-
soid, macular mycelium.
Nectria. Perithecia free, membranous,
flaccid, brightly coloured, with a pale
Dapilla, nucleus pale; asci eight-spored;
pores pellucid.

SPH.EROBOLUS.

SPH-dERONEMA.

Oomyces. Perithecia erect, several con-
tained in a shining1 sac, free towards the
upper part ; ostiole punctiform ; asci linear ;
spore filiform, very long.

Sphceria. Perithecia black, papilla covered
by a veil or by the matrix, sometimes beaked,
indurated, ostiolate, black ; asci usually
eight-spored j spores usually septate, dis-
charged as a powder.

Fig. 655.

Fig. 656.

Sphseria elongata.

Fig. 655. Erumpent lines of perithrcia. Nat. size.
Fig. 656. Portion of one in end view. Magnified 20

diameters.
Fig. 657. Asci and paraphyses from a perithecium.

Magnified 200 diameters.

SPH^EROB'OLUS, Tode.— A genus of
Isidularini (Gasteromycetous Fungi), con-
sisting of a peridium of several layers, the
inner one of which is suddenly reversed,
and discharges the globose sporangia.

BIBL. Tul. Fung. Hyp. t. 21. f. 11 ; Berk.
OutL tab. 21. f. 2 ; Cooke, Handb. 412.

SPH^EROCAR'PUS, Kiitz. = STAUBO-

CABPUS.

SPHJEROCAR'PUS, Mich.— A genus
of Ricciese (Hepatic®). S. terrestris (fig.
658) is a minute Liverwort growing on the
ground, especially, it is said, in clover-fields.
The fronds are from 1-4 to 1-2" long, palish
green, very thin and membranous, the lower
surface adhering to the ground by radical
hairs. The middle part of the upper surface
bears a quantity of fruits, which consist at
first of archegonia and antheridia, like those
of other Liverworts, surrounded by a cup-
like open pericheete (?), which gradually
grows up over the fertilized archegoniurn
and closes at the top, so as to form a pyri-
form sac, presenting an orifice at the summit.
The archegonium ripens into a globular

sporange, containing spores without elaters,
crowned by a curious little styliform process.
The spores are discharged by irregular rup-
ture. The walls of the sporange are com-
posed of simple parenchymatous cells, with-
out spiral-fibrous layers. While the spo-
range is ripening, the perichaete enlarges
into a loose, obconical, green membranous
sac, through the thin walls of which the
globular sporange is visible (fig. 658).

Fig. 658.

Bphaerocarpus terrestris.

A frond with perichsetes containing sporanges;

one cut open.
Magnified 10 diameters.

BIBL. Hook. Br. Flor. ii. pt. 1. 103 ; Bis-
choflf, Nova Acta, xiii. 150 ; Lindenberp*, ib.
xviii. 496 ; Fitt, Hooker's Jn. Sot. 1847, vi.
287.

SPHJSROOOO'CUS, Stackh.— A genus
of RhodymeniaceaB (Florideous Algas), con-
taining one British species, S. coronopifolius
(PI. 44. fig. 14), having a flat, linear, 'disti-
chously branched frond of crimson colour
and cartilaginous texture, of fan-like outline ;
parenchymatous, with an internal denser rib
and cortical layer; 6 to 12" long. The
unper branches have their margins set with
minute tooth-like processes, about 1-24"
long, in some of which the spherical concep-
tacles are imbedded.

BIBL. Harv. Mar. Alg. 128 j Greville,
Alff. Br. pi. 15.

SPH^EROIDI'NA, D'Orb.— A roundish,
sublobate, hyaline Foraminifer, near Globi-
gerina, but of denser structure, and folded
somewhat like a Miliola. Recent and fossil.

8. austriaca (PI. 24. fig. 4).

BIBL. Carpenter, Introd. For. 185.

SPJLEROM'PHALE.— A genus of Try-
petheliese (Angiocarpous Lichens), nearly
related to Verrucaria.

SPH^ERONE'MA, Fr. — A genus of
Sphaeronemei (Stylosporous Fun^gi), charac-
terized chiefly by the spores which emerge
from the pore becoming glued together into

SPH^ERONEMEI.

[ 705 ]

SPILEROPHORON.

a firm globule. The species, which grow
upon the surface of decaying plants, are pro-
bably only forms belonging to Sphseriaceous
genera.

BIBL. Berk. Br. Fl. ii. pt. 2. 281 ; Ann.
N. H. vi. 363, ib. '2. v. 371 ; Fries, Sum. Veget.
400.

SPILERONEHE'L— A family of minute
Stylosporous Fungi, growing on bark, or
more or less dry stems or leaves, charac-
terized by the conceptacle ordinarily burst-
ing by a pore or ostiole, or a lid, to extrude,
in most cases, a gelatinous ball of filaments
mixed with spores. From recent observa-
tions it appears that the genera do not con-
sist of independent species, but are forms
which occur in combination with Ascoiny-
cetous forms to complete the whole de-
velopment of an individual, — the Sphsero-
nemeous genera constituting the stylospo-
rous or conidial fruits of Sphseriacei, &c.,
corresponding perhaps to the tetraspores
found in the Florideous Algae, which also
possess proper spores (see SPH^BIA).
British genera :

Coniothyrium. Conceptacle free, mem-
branous, opening by an irregular pore at the
summit ; spores globular.

Leptostroma. Conceptacle innate, subum-
bonate in the centre, dimidiate, at length
falling oftj leaving a very thin disk.

Phoma. Conceptacle ostiolate, very thin,
innate, immersed, rounded, with a simple
pore ; spores oblong, simple.

Leptothynum. Conceptacle operculate,
innate, shield-shaped, not radiate-fibrous;
spores spindle-shaped, simple.

Actinothyrium. Conceptacle operculate,
innate, shield-shaped, radiate-fibrous ; spores
spindle-shaped, simple.

Microthecium. Conceptacle indehiscent,
membranous, immersed, endophytic ; spores
simple.

Cryptosporium. Conceptacle membranous,
opening irregularly at the summit ; spores
spindle-shaped, simple.

Sphceronema. Conceptacle horny, innate-
superficial, more or less produced into a
neck, ostiole simple ; spores oblong, simple.

Acrospermum. Conceptacle leathery ex-
ternally, fleshy within, elongate-clavate,
ostiole simple ; spores stick-shaped, simple.

Diplodia. Conceptacle homy, innate-su-
perficial or immersed, perforated by a pore
or irregularly opened or ostiolate, ostiole
more or less produced ; spores ovoid or
ellipsoid, double, then halved into com-
pressed-ternate semieUipsoid sporules.

Hendersonia. Conceptacle fleshy, super-
ficially innate or immersed, perforated by a
pore, opening irregularly or ostiolate, ostiole
more or less produced j spores globose, cylin-
drical, or discoid.

Septoria. Conceptacle horny, innate -im-
mersed, rounded, ostiole simple ; spores
cylindrical, septate.

Vermicularia. Conceptacle bristly, de-
pressed, bursting irregularly ; spores minute,
linear.

Neottiospora. Conceptacles immersed ;
spores appendaged at one end with short
hyaline threads.

Prosthemium. Conceptacle horny, immer-
sed, ostiole simple; spores transversely
septate, verticillate at the apex of their fila-
ments.

Asteroma. Conceptacle very small,
slightly prominent, close, subconfluent,
seated on more or less distinct radiating
fibrils.

Angiopoma. Conceptacles free, mem-
branous, somewhat horny, cup-shaped, de-
hiscing by a circular mouth, provided with
a fugacious epiphragm ; spores affixed at
the base, stalked, septate.

Discosia. Conceptacles innate, somewhat
carbonaceous, at length collapsed and plicate,
ostiole perforated ; spores fusiform, produced
at both ends into a thread-like point.

Piggotia. Conceptacles very irregular,
thin, obsolete beneath, confluent into a ru-
gulose patch, bursting by an irregular crack ;
spores on short stalks, largish, obovate,
somewhat constricted towards the base.

Phlyctana. Conceptacle spurious, formed
by the blackened epidermis; spores fusi-
form, cuspidate, septate, emerging accom-
panied by a gelatinous mass.

Glceosporium. Conceptacle absent ; spores
covered only by the cuticle, which separates ;
spores stalked, longish, elliptical, simple,
exuding a gelatinous tendril.

Dilophosphora. Conceptacle immersed in
a spurious stroma, covered, perforated by a
pore ; spores cylindrical, continuous, crow-
ded at both ends with radiating filiform
appendages.

Sphceropsis. Conceptacle spherical, im-
mersed, subiiinate, astomous, at length (by
the separation of the epidermis) bursting by
circumscissile dehiscence or irregularly.
Spores simple.

SPH^EKOPH'ORON, Pers.— A genus of
Epiconiodei (Lichenaceous Lichens). Thal-
lus erect, shrubby, externally crustaceo-car-
tilaginous, internally solia and cottony.

2z

SPfLEROPHRYA,

[ 706 ]

SPH^EROPLEA.

Apothecia terminal, spherical, tlie perithe-
cium, formed of the tliallus, closed, dehiscing
irregularly. Nucleus globular, internally i
floccoso-cartilaginous, the discharged (black) i
sporidia crowded in the circumference.

S. coralloides (fig. 395, p. 463), and S.fra- \
ffile, common on sand-rocks, among mosses.

S. compactum is rare. The spermogonia
occur at the ends of the more delicate
branchlets of the thallus.

BIBL. Hook. Br. Fl ii. pt. 1, 236 ; Leigh-
ton, Lick. Fl. 48 5 Tulasne, Ann. So. Nat. 3.
xviii. 209.

SPBLEROPH'RYA, Clap, et Lach.— A
genus of Acinetina.

Char. Tentacles simple, radiate ; no sheath
or peduncle ; body free.

S. pusilla, small, spherical; freshwater.
(Clap, et Lach. Inf. 385.)

SPELEROP'LEA, Ag.— A genus of Con-
fervacese of uncertain position, but proba-
bly allied to the Chsetophoracese. It is cha-
racterized chiefly by the formation of the
spores. The plants consist of simple fila-
ments, with long joints, at first containing
green colouring-matter excavated by large
vacuoles, producing a banded appearance
(PL 9. fig. 14 a), the contents in the fertile
cells finally resolving themselves into nume-
rous spiuulose globular spores arranged in
longitudinal rows (b), which become red
when ripe.

The development of the spores of S. annu-
lina has been observed by several authors ;
and Cohn has published an account of the
formation of spermatozoids in distinct cells,
exercising a fertilizing function. The fila-
ments, which always terminate in pointed
hair-like ends, present when actively vege-
tating the excavated or banded appearance
of the green contents above noticed ; the
vacuoles separating the bands of a proper,
colourless, mucilaginous coat. When about
to produce spores the regularity of the bands
vanishes, the vacuoles multiply in number in
the substance of the bands, and the contents
present the appearance of a green froth with
starch-granules scattered through it. After
a time a number of green corpuscles, the
spores, appear in the median line of the cell ;
these assume a stellate shape, with radiating
threads of protoplasm connecting them to-
gether j they soon appear in pairs, separated
by transverse false septa, formed by the
flattened vesicles of the vacuoles. The spores
gradually become better defined, and the
false septa disappear ; then the young spores
present themselves as globular bodies, de-

void at this time of a cellulose coat. From
two to six minute orifices are preceptible at
this time in the partially softened wall of
the parent cell. While these phenomena are
occurring in some of the cells, a different
change takes place in others. The green
bands assume a reddish-yellow colour, their
starch disappears, and they are gradually
converted into myriads of short stick-shaped
bodies, which break apart and u swarin " in
vast numbers, filling the whole cell, moving
actively in all directions. The gelatinous coat
of some of the vacuoles sometimes remains
intact ; and these then lie free in the cavity
of the cell, and are often carried about by
the rapid motion of the corpuscles. Orifices
are meanwhile formed in these cells also,
through which the stick-shaped bodies
(spermatozoids) escape into the water. Their
length is about 1-3000". The hinder end
now appears somewhat swollen, and they
bear two long cilia on the pointed beak — in
fact resembling the microgonidia of the other
Confer voids. Cohn states he has seen them
accumulate around the orifices of the spore-
cells, enter the cavities of these, and swarm
about in the interior, in considerable num-
bers, at length adhering to the young spores.
These resting-spores then acquire a mem-
brane, and under this a second , which is
at first smooth, but afterwards presents a
spinulose or stellate appearance; the first
coat is then thrown off, and a third, smooth
coat appears under the stellate coat, closely
investing the contents. These conditions
resemble those of the spores of SPIEOGYRA
and other Confer voids ; Spirogyra, however,
retains the outer coat until germination.
The green contents of the spores ultimately
turn red. Their size and number in a cell
vary much.

Cohn has also observed the germination
of these spores, which is interesting in se-
veral respects. Their ordinary size is from
1-1200 to 1-1500" ; and they present, as
above mentioned, two coats, the outer ele-
gantly marked ; most authors describe it as
stellate ; Kiitzing asserts that it is spirally
folded. The real fact is, that it is plaited
in the direction of meridians from pole to
pole, and thus appears stellate when seen at
either pole, marked with lines when seen
sideways. The spores do not appear to ger-
minate until the spring following their pro-
duction. The red contents begin to assume
a green colour from the surface inwards,
divided into two, then into four or eight
portions, which break out from the spore-

SPELEROPSIS.

[ 707 ]

SPILEROZYGA.

cell, and swim about as free biciliated zoo-
spores, of globular or shortly cylindrical
form, from 1-2280 to 1-1680" long, either ;
bright red or particoloured red and green, j
the point bearing the cilia, however, always ;
colourless. After a time they become
coated with a cellulose membrane, cease to |
move, and grow into a spindle-shaped body,
the ends prolonged into hair-like points.
The growth appears to be always in the
middle, the hair-like points remaining;
thus the spindle-shape is retained until the
length reaches 1-24' or more, and the first
septum appears in the middle of the filament.

•S". annulina (PI. 9. tig. 14) appears to be
the only well-known form. It is a rare
Conferva, growing on flooded fields ; it
does not seem to have been recorded in
Britain.

For Sph. crispa and punctalis, see ULO-
THBIX.

BIBL. Kiitz. Sp. Alg. 362, & Tab. Phyc. -,
Braun, Verjihufitng, Ray Soc. 1853, 165;
Cohn, Ber. 'Berlin. Ak. 1855 ; Ann. Sc.Nat.
4. v. 187 ; Ann. N. H. 2. viii. 81 ; Cienkowski, |
Bot. Zeit. xiii. 777 ; Rabenht. Alg. iii. 318. j

SPH7EROPSIS,Lev.— AgenusofSphaa- \
ronemei (Stylosporous Fungi), growing
upon stems, &c. ; apparently only stylospo-
rous forms of Sphaeriaceous genera.

BIBL. Fries, Sum. Veget. 419 ; Tulasne,
Ann. Sc. Nat. 4. v. 115.

SPH^EROP'TERIS, Wall.— A genus of
Dicksonieae (Polypodiaceous Ferns). 8.
barbata ; India. (Hooker, Syn. 49.)

SPH^EROSIRA, Ehr. See VOLVOX.

SPH^EROTHE'CA.— A genus of Sphse-
riacei (Ascouiycetous Fungi), closely allied
to Erysiphe. S. pannosa is common on the
leaves and fruits of a rose ; 8, Castagneij on
the leaves of hops &c. (Cooke, Handb. 645 ;
Tulasne, Carp. i. 208.)

SPELEROT'ILUS.— A genus of Crypto-
cocceae, consisting of cells arranged in rows,
connected by mucus, forming a flocculent,
variously divided floating layer. S. natans
(PI. 3. fig. 21), brownish, in organic liquids :
said to purify the water.

BIBL. Rabenht. Alg. ii. 8; Eyferth, Jn.
Mic. Soc. 1881, 97.

SPH^EROZOS'MA, Corda.— A genus of
Desmidiaceae.

Char. Filamentous; filaments flat, fra-
gile, their component cells closely united
by means of minute (glandular) processes,
and deeply divided on each side into two i
segments.

S. vertebratum (PI. 14. fig. 9, front view ;

fig. 10, side view). Cells about as long as
broad ; connecting processes oblique, one on
each side. Length of cell 1-1430". Not
uncommon in ditches.

S. excavatum. Cells longer than broad ;
connecting processes sessile, two on each
side. Length of ceU 1-2570".

After separation, the cells conjugate ; spo-
rangia elliptical. Other species.

BIBL. Ralfe, Br. Desmid. 65; Rabenht.
Alg. iii. 148.

SPILEROZO'UM.— A genus of Radio-
larian Rhizopoda.

It consists of a spherical group of rounded
bodies consisting of sarcode witk distinct
nuclei, surrounded by a zone of siliceous
spiculea, the whole being imbedded in a com-
mon gelatinous matrix. The centre of the
mass is vacuolated; and the whole often
becomes a hollow sphere. (Huxley, Comp.
Anat. ; Carpenter, Microscope.}

SPH^EROZ'YGA, Agardh (Anakena,
Bory, BrtSbisson). — A genus of Nostocha-
ceae, differing from the allied genera only in
the sporangia! cells being separated by vesi-
cular cells. As the sporangial cells are de-
veloped from the ordinary cells, and this
gradually, the vesicular cell will appear at
certain epochs to have a sporangial cell on
one side and an ordinary cell on the other ;
but this arises merely from the fact that
the sporangial cells are developed singly
and successively, first one on one side of
the vesicular cell and then one on the other,
and so on, to whatever number of adjacent
sporangial cells there may be developed on
either side of the vesicular cell ; and those
nearest the latter will therefore always be
the largest, until the whole have acquired
the full size. Ralfs describes seven British
species.

* Filaments moniliform; sporangia elongated,
not turgid.

S. Carmichaelii. Filaments with tapering
extremities; ordinary joints distinct, sub-
quadrate ; sporangial cells oblong ; vesicular
cells spherical.— Rails, Ann. N. H. 2. v. pi.
8. fig. 7 ; Harvey, Phyc. Br. pi. 113 A ; Mar.
Alya, 2. ed. pi. 27. fig. D.

Beloniatorulosa,Carniicha.el ; SpJuerozyga
compacta, Kiitz. ; Anabana marina, Bre"bis-
son ; Cylindrospermum Carmichaelii. Kiitz.
Sp. Alg. 294, Tab. Phyc. i. pi. 99.

Var. tenuissima, with very slender fila-
ments. Forming a tender, very thin stra-
tum of a dark or bluish-green colour, on the
damp soil of salt-marshes flooded at spring
2z 2

SPHAGNACE^E.

[ 708 ]

SPHAGNACE^E.

tides, more rarely in brackish ditches, or
upon decaying marine Algse.

The best distinctive marks of this species
are, the subacute extremities, combined
with the short filament and littoral habit.

S. Jacobi. Filaments elongated, their ends
usually attenuated ; ordinary cells subsphe-
rical; vesicular cells spherical; sporangial l
cells oblong or cylindrical. — Ralfs, /. c. pi. 8.
fig. 8; Eng.Bot. 2826. fig. 2. Forming thick,
bluish-green, gelatinous masses, from which
the filaments issue in long rays. Fresh-
water.

S. elastica (PI. 8. fig. 3). Dissepiments
conspicuous ; ordinary cells quadrate ; vesi-
cular cells elliptic; sporangial cells cylin-
drical, truncate.— Ralfs, L c. pi. 8. fig. 9.
Cylindrospermum elongatum, Kiitz. Tab.
Phyc. i. pi. 99. fig. 3. Forming a tender
stratum, of a deep bluish colour, in bogs.

** Filaments moniliform; sporangia turgid,
much broader than the ordinary cells.

S. Broomei, Thwaites. Filaments elon-
gated ; ordinary cells suborbicular ; vesicu-
lar cells barrel-shaped or elliptic ; sporangial
cells elliptic, catenate. — Ralfs, I. c. pi. 7.
fig. 10. Forming a firmish bluish- or yel-
lowish-green stratum in brackish ditches.

S. Berkeleyana, Thwaites. Ordinary i
cells spherical or slightly compressed ; vesi- '
cular cells spheroidal, compressed, as broad
as the large, turgid-elliptic, sporangial cells.
—Ralfs, L c. pi. 8. fig. 11. In brackish
ditches.

S. Mooreana, Ralfs. Ordinary cells sub-
spherical; vesicular cells barrel-shaped,
much narrower than the large, broadly
elliptical sporangial cells. — Ralfs, /. c. pi. 8.
fig. 12. An Irish species.

*** Dissepiments obscure ; cells longer than
broad.

S. leptosperma (Kiitzing). Filaments
elongated, not constricted at the dissepi-
ments ; ordinary cells longer than broad,
confluent ; vesicular cells elliptic ; sporan-
gial cells linear.— Ralfs, 1. c. pi. 8. fig. 13.
Cylindrospermum leptospermum, Kiitzing,
Tab. Phyc. i. pi. 99. fig. 2. Forming large
shapeless gelatinous masses in still waters,
varying from deep green to yellowish green,
or, when the filaments are comparatively
few, nearly colourless. Distinguished espe-
cially by the "confluent ordinary cells with
obscure dissepiments."

SPHAGNA'CE^E.— A family of Clado-
carpous Mosses, of peculiar habit, growing

in bogs &c., distinguished especially by the
mode of branching, the structure of the
leaves, sporanges, and antheridia, and by
the absence of roots, except in the early
stages of growth.

The stem of the Sphagna is composed of
three layers of cells, — a cortical, a medullary,
and an intermediate prosenchymatous layer,
which finally becomes somewhat woody.
The primary axis is indefinite in its growth ;
the lateral axes, sterile or fertile, are an-
nual. The secondary axes are fasciculate ;
and being pendent or recurved upon the
stem, they fulfil in some measure the func-
tion of roots. The leaves are remarkable for
their cellular structure, being composed of
two kinds of cells — namely, narrow and
elongated cells filled with chlorophyll, con-
joined into a kind of network, the meshes
of which are occupied by large hyaline cells.
The hyaline cells contain, in all but one
exotic species, a spiral or annular secondary
deposit (PI. 48. fig. 25) characteristic of
this family. These large cells also become
opened by regular circular pores at a certain
stage of growth.

The inflorescence is monoecious or di-
oscious. The antheridia are produced singly
in the axils of perigonial leaves at the club-
shaped tips of short branches. They are
pedicellate and roundish, like those of the
Liverworts ; they produce biciliated sper-
matozoids. The archegonia are found about
four together, sessile, in a tuft of perichae-
tial leaves occupying the axis of a fascicle
of branches, the receptacle subsequently
elongating into a peduncle, bearing a glo-
bular capsule, entirely surrounded by the
calyptra. The calyptra is ruptured near the
middle, the lower part persistent and con-
tinuous with the fleshy vaginule, within
which the capsule is seated on a bulb-like
pedicel ; peristome none ; operculum flattish,
thrown off with elasticity. Spore-sac
wanting ; columella short, not reaching the
mouth of the capsule. Spores apparently of
two kinds, some enclosed four together in
parent cells, others smaller, sixteen in one
parent cell; the former fertile, the latter
sterile, occuring either together or in di-
stinct capsules. The spores in germinating
produce a Marchantioid body, very different
from the confervoid mass of ordinary mosses.

British Genus.

Sphagnum, Dill. Character that of the
order. Nine species occur in Britain, some
common on every bog, distinguished by

SPHAGNOCCETIS.

[ 700 ]

SPINAL CORD.

their brilliant yellow-green colour and the
•wet, spongy character of the beds they form.
The leaves are very interesting microscopic
objects.

Rotatoria are sometimes found in the cells
of the leaves. Also upon or within the
same, the carious parasitic Rhizopod —
CMatnydopyxu labt/rmthuloides. This, in the
resting-stage, consists of a laminated thick-
walled cellulose red or green cell. As the
organism grows, it bursts the cell-wall, and
the protoplasm issues in the form of nu-
merous very slender radiating filaments,
along which glide minute fusiform bluish-
green amoeboid bodies. It seems to bear
analogy with the Myxomycetes.

BIBL. Wilson, Bryol. Br. 14; Schimper,
~l>tn. Sc. Nat A. i.313; Braithwaite, Mosses-,
Archer, Qu. M. Jn. 1875, xv. 107 (Chla-
•mydopyxia) ; Husnot, Sphag. Europ. 1882.

SPHAGNOCCE'TIS, Nees.— A genus of
Jun^ermanniesB (Hepaticse), containing one
species, S. (Jung.} Sphagni, an elegant little
plant growing over Sphagnum and other
mosses on bogs ; attaching itself by long
radicles, numerous on the under side of the
procumbent, nearly simple stem. The gem-
miferous branches only have amphigastria.

BIBL. Hook. Br. Fl. ii. pt, 1. 113; Br.
Jung, pi. 33, and Suppl. pi. 2 ; Ekart, Syn.
Jung. pi. 6. figs. 43 & 48.

SPHENE. See ROCKS.

SPHENEL'LA, Kiitz— A genus of Dia-
tonmceae.

This genus appears to consist of the de-
tached frustules of Gomphonema. Kiitzing
describes seven species. S. vulgaris (PI. 19.
fig. 19).

BIBL. Kiitz. Bacill. 83, Sp. Ala. 62;
Rabenht. Ala. i. 282.

SPHENODE'RIA, Schlum.— A doubtful
genus of Arcellina (Rhizopoda).

It is allied to Euglyphe and Trinema.

BIBL. Pritchard, 'infusoria, p. 557.

SPHENOM'ONAS, Stein.— A genus of
Flagellate Infusoria. Free, surface hard ;
flagella two, one long, one short ; a tubular
pharvnx. Two species ; freshwater. (Kent,
/wf.438.)

'SPIIEXOSI'RA, Ehr., Kiitz.— A genus
of freshwater Diatomaceae. DIATOMACE.E:,
p. 244.

S. catena (PI. 17. fig. 26).

BIBL. Kiitzing, Sp. Alg. 68; Rabenht.
Fl. Eur. Alg. i. p. 293.

SPHINCTOC YS'TIS, Hass.,=CYMATO-

PLEUBA, Sm.

SPHINCTRFNA.— A genus of Calyciei

(Lichenaceous Lichens), with little stalk-
like excipula and scarcely distinguishable
thallus, growing on leave's or Pertusaricc.
(Leighton, Lich. FL 38.)

SPICULA (plural of spiculum). — In some
of the lower Invertebrata, firmness is given
to the body by a kind of internal and
external skeleton consisting of a number of
curiously shaped microscopic bodies, many
of which are of a needle-like form, often
containing a cavity, and denominated spi-
cula. They are met with in endless variety
of form in sponges (see SPONGIDA) (PI. 45,
the lettered objects), where they usually
consist of silex, some being of carbonate of
lime. They also occur as anchors &c. in the
Echinodermata (PI. 45. figs. 1 h, i, k, I, and
19 a, b, c), the Foraminifera (PL 23. fig. 24),
and in some of the Zoophytes (Alcyonium)
and Mollusca (Doris), in these instances
being calcareous.

There can scarcely be doubt that spicula
are homologous with the elements of shell ;
but little or nothing is known of their
development. They form very interesting
microscopic objects, on account of their
remarkable forms.

To prepare them, the animal substance
in which they are contained should be
boiled with nitric acid if they are composed
of silex, and with dilute solution of potash
if they consist of lime-salts. They may be
preserved by mounting in Canada balsam.

They are commonly met with in sea-
mud, and as fossils in some rocks.

SPIDERS. See ABACHNIDA.

SPILOC^EA, Fr.— A genus of Torulacei
(Conioinycetous Fungi). S. Pomi occurs
upon apples, in contiguous efrused patches,
from which the epidermis separates in frag-
ments, exposing the simple globular spores,
adherent to each other and to the matrix.

Probably only a state of Cladosporium.

BIBL. Berk. Br. Fl. ii. pt. 2. 360 ; Fries,
Sum. Veget. 482.

SPILONE'MA, Fries.— A genus of Col-
lemaceous Lichens.

Char. Thallus filiform, branched, fruti-
culose, granula gonima large, in transverse
strata. Apothecia lecideine, lenticular.
Spermatia shortly cylindrical. 3 species,
on rocks. (Leighton, Lich. Flora, 10.)

SPINAL CORD.-The spinal cord of
man is that part of the central nervous
system which extends downwards from the
medulla oblongata, occupving much of the
vertebral canal, and terminating in a conical
extremity at the level of the first lumbar

SPINES.

[ 710 ] SPIRAL STRUCTURES.

vertebra. The cord is composed of white
substance, grey substance, and blood-vessels
(PI. 52. fig. 7).

The white substance («) is mostly ex-
ternal, and forms the antero-lateral and
posterior longitudinal columns, besides the
transverse anterior commissure at the end of
the anterior longitudinal fissure. It is com-
posed of nerve-fibres of large and medium
size, of connective tissue, and blood-vessels.
The grey substance (c) is internal, and in
transverse section of the cord presents a
shape which may be roughly compared
with that of the letter H. On either side
there is an anterior and posterior horn or
cornu ; and the median line of the letter is
represented by a soft grey commissure per-
forated by a canal, which is central and
lined with epithelium. Surrounded on all
sides by the white substance, the anterior
and posterior spinal nerves reach their re-
spective cornua Dy crossing at different angles
along two lines on either side of the ge-
neral direction of the nerves of the white
substance.

The grey substance contains a large num-
ber of very fine nerve-fibres, which are
united in a plexiform manner with nerve-
or ganglion-cells ; most of these fibres pass
outwards and become spinal nerves, belong-
ing then to the white substance or to di-
stinct nerves. There is moreover granular
matter with highly refractive globules, and
extremely small nucleated cells surrounding
the nerve-fibres and ganglion-cells. Much
connective tissue exists in the neighbourhood
of the central canal and in the posterior
cornu.

The examination of the spinal cord and
the brain is so difficult and not likely to be
the subject of general investigation, that
we must refer to the BIBL. for further de-
tails.

BIBL. Todd's Cycl. An. $ Phys. ; Lockhart
Clarke, Phil Tr. 1858, 1868 ; Strieker's
Hist. ii. ; Frey, Hist., and the Bibl

SPINES OF ANIMALS.— These are pro-
perly stout rigid and pointed processes of
the integument, formed externally by the
epidermis, and internally of a portion of the
cutis or corresponding structure; but the
term is frequently applied to stout rigid and
pointed processes of the epidermis only.

See HAIRS, and the notices of the struc-
ture of the integument under the heads of
the various classes.

SPIRACLES or STIOMATA of animals.
— The external orifices of the tracheae of

Insects and Arachnida. The respiratory
tubes of these animals have no communica-
tion with the mouth, but terminate exter-
nally in orifices situated upon the surface of
the thorax or abdomen. These are mostly
rounded or elliptical (PI. 35. figs. 3, 7, 8,
and 9 «), sometimes in the form of small
clefts, and are often furnished with a kind
of nioyeable valve, or bounded by a thick-
ened rim ; sometimes a sieve-like structure
(PI. 34. fig. 34) prevents the admission of
foreign bodies, or they are surrounded by
hairs or scales effecting the same purpose.

They are often situated at the lateral
and upper portions of the abdomen, at the
posterior, lateral, and upper part of the
thorax, &c.

See ARACHNIDA, INSECTS, and the
genera.

SPIRAL STRUCTURES OF PLANTS.—
Among the most elegant of the microscopic
objects furnished by the Vegetable King-
dom are the various forms of the secondary
deposits upon the walls of cells, vessels, and
ducts, &c., which present the appearance of
fibres coiled into perfect spirals, or of spiral
fibres either with the coils detached and
forming rings, or with the coils more or less
connected by cross pieces, producing a re-
ticulated structure.

Under the head of SECONDARY DEPOSITS
it is stated that this spiral-fibrous deposit
may be taken as the character of a group of
structures to be contrasted with those struc-
tures described as PITTED ; and that the
essential distinction in the nature of these
two groups lies in the greater extent to
which the primary wall is covered in the
pitted structures. This is not quite absolute
in reference to all spiral-fibrous structures,
as in the true unrollable spiral vessels and
similar organs the coils of the spiral fibres
are often closely in contact, although not
adherent to each other. It has been stated
| that the various forms of the open spiral,
annular, and reticulated deposits are modi-
fications of the simple close spiral ; but this
must be understood only in a morpholo-
gical sense, since there is no actual change
of condition ensuing with age, as has been
assumed by some authors, the fibrous layers
being always originally deposited on the
primary wall in the form and pattern which
they ultimately possess. There appears to
be no real opening of the spirals or break-
ing up into rings, in consequence of the
expansion of the primary wall to which
they are attached,

SPIRAL STRUCTURES,

[ 711 ]

SPIRAL STRUCTURES.

It will be convenient, in the first place,
to speak of the distinct well-marked struc-
tures ordinarily known as spiral cells and
vessels, occurring in the stems, leaves, &c.
of the higher plants, before describing cer-
tain other forms found in special organs,
and to reserve to the end some points re-
lating to the ultimate constitution of the
secondary membranes of cells. Spiral
structures are usually divided into true
spiral, annular, reticulated, and scalariform
organs.

Spiral cells and vessels are perhaps the
most generally diffused of the forms. The
name spiral vessel is given to elongated
cylindrical cells tapering to a point at both
ends, with a spiral-fibrous deposit lining the
primary wall (fig. 659, and PI. 48. figs. 8, 11,
12). The spiral fibre may be either single,
as is most common, double (fig. 659) ; or

Fig. 659.

Fig. 660.

the internal organs they can only be ob-
served in sections, or when extracted by
maceration: in delicate vessels and petals
they may often be observed through the
transparent epidermis. The coiled spiral
fibre is mostly elastic enough to bear
stretching open like a wire spring ; in this
case the primary wall is torn between the
coils, and its ragged edges may sometimes
be detected. The uncoiled fibres are often
seen still unbroken when a hyacinth or
similar leaf is broken across and the pieces
gently drawn apart. Annular vessels closely
resemble the preceding, except that the
fibrous deposits are in the form of detached
j rings (fig. 661) ; they are the rarest forms ;
they are especially remarkable in the Equi-
setaceae. The reticulated, again, have irre-
gular spiral coils or rings connected more
or less by perpendicular or oblique bars
(fig. 662, and PI. 48. fig. 9) into a network.
These two modifications are usually of larger
diameter than the true spiral vessel, and
the reticulated larger (also of later origin in
the organs) than the annular. However,
mixed forms occur not uncommonly, partly
annular, partly spiral or reticulated (fig. 663) .
They are found in similar situations, but
generally do not extend into the more de-
licate organs. Spiral, annular, and reticu-
lated vessels may be prepared in most beau-
tiful forms and large size from portions of
the leaf-stalk of rhubarb, of the stem of the
garden-balsam, the melon, &c.

Fig. 661. Fig. 662. Fig. 663.

Fig. 659. Fragments of spiral vessels from the Melon.
Magnified 200 diameters.

Fig. 660. Magnified diagram of a section of the base
of a leaf-stalk arising from a Dicotyledonous shoot,
showing the position of the spiral vessels in the leaf-
stalk and next the pith of the shoot, the spiral fibres
being uncoiled and a little drawn out.

a number of fibres may run parallel (Mu-
,«a, Nepenthes, Zingiberacece, Marantacece).
These spiral vessels occur as the first vascu-
lar formation outside the pith (MEDULLARY
SHEATH) in almost all the Dicotyledons
(fig. 660), and as the first vascular forma-
tion in the vascular bundles of the stems of
Monocotyledons — also of all other vascular
bundles, forming the ribs or veins of pe-
tioles, leaves, bracts, sepals, petals, &c. In

Fig. 661. Fragment of an annular vessel from the
ified

Melon.
Fig. 662

Magnified 200 diameters.
. Portion of a reticulated vessel from the

Melon. Magnified 200 diameters.
3. Frag

Magnified 200 diameters.

Fig. 663.
the Melon.

ragment of a spiral and annular vessel from

Spiral and other vessels are usually simple

SPIRAL STRUCTURES. [ 712 ] SPIRAL STRUCTURES.

at first (branched spiral vessels do occur,
more rarely), but ordinarily unite together
by a kind of fusion. The conical extremities
overlap to a certain extent (fig. 659) ; and
thus the articulation is more or less oblique.
This fusion is much more evident and com-
plicated in roots, rhizomes, and abbreviated
stems than in stems with developed inter-
nodes. The elementary cells are then gene-
rally much shorter ; and the vessels formed
from them branch out in various directions
through the tissue. This is very well seen
in the roots of many herbaceous plants,
such as the dandelion, chicory, &c., and at
the point of origin of the vascular bundles
of adventitious roots generally.

The above-mentioned confluent spiral
vessels pass insensibly into the ducts, which
are similar confluent rows of cells forming
parts of the solid wood of stems, composed
of cells with flat ends applied together.
They may resemble in their markings the
preceding forms, but in their varied con-
ditions form a series leading towards the
PITTED DUCTS. The scalanform vessels or
ducts (fig. 664, and PI. 48. fig. 10), so called
from the ladder-like markings, are a very
regular form of the reticulated type — this re-
gularity appearing to depend, however, upon
the relation between the markings of the ad-
j acent organs. In the PITTED DUCTS we find
the pits only opposite to other pits, therefore
on the sides adi acent to other ducts or to cells ;
in the scalariforin ducts
a spiral-fibrous deposit
is conjoined into a net-
work by vertical fibres
placed opposite the in-
tercellular passages or
the meeting angles of
contiguous cells or
ducts, leaving regular
slit-like spaces opposite
the cavities of the adja-
cent cells. This form
is especially charac-
teristic of the Ferns ;
but it occurs also com-
monly in the Dicoty-
ledons in a less regular
form, passing quite in-Fragment8ofscalariform
sensibly into PITTED vessels from a Fern.

DUCTS, as in the wood Magnified 200 diameters,
of Eryngium maritimum
(PI. 48. fig. 21). The scalariform vessels
of Ferns are often slightly unreliable.

It is mentioned under PITTED STRUC-
TURES, also, that a combination of the two

Fig. 664.

types sometimes occurs in the same cell.
This is the case in the ducts of the Lime,
Mezereon, and other plants (PI. 48. fie-s. 4,
13, & 19).

Besides the generally diffused spiral and
other vessels and ducts above described,
cells, properly so called (that is, such as
never become elongated very greatly in one
particular direction), belonging to particular
organs and plants, present the same kind of
markings. The ducts and vessels, indeed,
in many cases are formed of very short
cellular elements ; but these may be distin-
guished from proper cellular tissue charac-
terized by spiral secondary deposits. Under
this head may be cited first certain wood-
cells. In the Cactacese, the prosenchyma-
tous tissue of the stem presents remarkable
spiral and annular cells, in which the fibre
becomes so much thickened that it projects
like a riband set with its edge against the
cell-wall (PI. 48. fig. 7). The wood of the
Mistletoe (figs. 665, 666) also exhibits spiral-
fibrous cells : that of the Yew (TAXUS) is
composed of true spiral-fibrous cells and
others with bordered PITS and an internal
spiral fibre in addition (PI. 48. fig. 4). In
the stems of the Leguminosae, parenchy-
matous portions occur in the midst of the
wood, the cells of which exhibit spiral fibres
(Ulex, Spartiutn). The cellular tissue near
the surface of the roots of the epiphytic
Orchids (PL 48. fig. 6) affords another ex-
ample, as also some of the subepidernial
cells of the leaves (fig. 667). The layers of

Fig. 665. Fig. 666. Fig. 667.

Fig. 665. Annular-fibrous cell from the stem of Mistle-
toe. Magnified 200 diameters.

Fig. 666. Cell intermediate between reticulated and
pitted, from the Mistletoe. Magnified 200 diameters.

Fig. 667. Spiral-fibrous cell from the leaf of an Orchid.
Magnified 200 diameters.

cells lining the ANTHERS of Flowering-
plants are characterized by most varied
patterns of spiral markings (PI. 40. figs. 1-5) ;
m these cells, moreover, we sometimes see
the connexion between the fibrous and ho-
mogeneous deposits well illustrated, as the
cells may have one or more sides marked
with spiral fibres, while the remainder of

SPIRAL STRUCTURES, [ 713 ] SPIRAL STRUCTURES.

the wall is covered with a continuous layer.
A similar structure, generally with perfect
spiral fibres, occurs in the walls of the spo-
ranges ofjunycrmminia, Marchantia (PL 40.
fig. 35), and other Liverworts. With these j
are nearly connected the structures called i
ELATERS, which are found mixed with the I
spores in the same plants. These are tu-
bular cells containing a single or double
elastic spiral fibre (PI. 40. figs. 36-38),
exactly analogous to the spiral vessel in
structure. Elaters of similar nature occur
even among the Fungi, as in the sporange
of THICHIA (PI. 40. figs. 39, 40). The ela-
ters of the Equisetaceee (fig. 205, p. 300)
are of different character, consisting of four
short filaments with clavate ends, attached
at one side of the spore and originally
coiled round it, ultimately unrolling with
elasticity. They appear to be formed by
the deposition of a spiral-fibrous layer on
the wall of the parent cell of the spore,
within which the true (single) spore-men-
brane is formed, unadherent ; and when the
spore is ripe, the spiral-fibrous layer splits
up and starts away from the inner coat.
An elegant spiral and annular fibrous struc-
ture is also met with in the large cells of the
leaves of the SPHAGNACEJE (PL 48. fig. 25) ;
this is exactly analogous to the similar de-
posits in the higher plants. Spiral layers
are found, less distinctly, in the radical
hairs growing from the lower surface of the
frond of MARCHANTIA. Nageli regards
them as folds of an inner layer of mem-
brane ; but they appear to be regular secon-
dary deposits.

Lastly, the hairs and similar epidermal
appendages sometimes exhibit spiral -fibrous
deposits. An unreliable spiral fibre is
beautifully arranged in the cells forming
the mealy coating of the seed of Cobeea
scandens (PL 28. fig. 20). The seeds of many
of the Acanthacese (figs. 21 & 24), Collomia
(fig. 22), the pericarp of some of the Labiatae
(fig. 23) and CompositaB (SENECIO) bear
tubular hairs, consisting of cells with a spiral
or annular fibre in their interior (see HAIRS
of Plants). The structure of the hairs of
Collomia, Ruellia, &c. has been much dis-
cussed, but it seems very simple : they ap-
pear to consist of a short tubular cell, upon
the wall of which a closely coiled elastic
spiral-fibrous layer is deposited ; during the
ripening of the seed the primary membrane
undergoes a metamorphosis into a substance
related to amyloid (or bassorine ?), which
softens and swells up when placed in water,

allowing the spiral fibre to extend itself (PL
28. tigs. 21, 22 b, c). Sulphuric acid and
iodine give the swollen gum-like envelope a
purplish tint.

Another and less distinctly marked spiral
arrangement of the substance of the cell-
walls occurs in the form of cracks or gaps
in certain of the layers of the secondary
deposits, running more or less round the
cell, appearing like irregular spiral streaks ;
these are sometimes present in the earlier
secondary layers and not in the later, so
that the " cracks " are covered in by the
latter and converted into canals in the sub-
stance of the cell -wall. These occur in the
wood-cells of Hernandia sonora, in the pros-
enchymatous cells of the vascular bundles
of Caryota urens, Phoenix, Metroxylon, and
probably in other cases. Something similar
may be detected in the wood-cells of Finns
(PL 48. fig. 1), especially after treatment
with boiling nitric acid. In liber-cells a
spiral texture is far more generally evident.
In Vinca, for instance (PL 48. fig. 30), and
other Apocynaceous plants, a delicate spiral
striation of the wall is evident in its natural
state, beautifully regular in its arrange-
ment; a similar 'appearance may often be
detected in the walls of thickened hairs,
especially when acids are applied, as in
Cotton (PL 28. fig. 1 b), particularly in gun-
cotton (fig. 1 c) — sometimes with interme-
diate slits, as in Urtica (fig. 8), &c. ; and
by boiling with nitric acid, a minute spiral-
fibrous structure may be detected in the
secondary layers of the liber-cells of very
many plants, as of Flax (fig. 2 b, c), Coir
(fig. 5 a, b), Bcehmeria (fig. 25 b, c), &c.
All these spiral structures belong to the
secondary deposits of the cells ; they are
mostly distinguishable from those previously
described by being thinner places or lines
left bare, instead of being lines of deposit.

We have observed a somewhat similar
spiral streaking of the walls of Hydrodictyon,
depending on slits in certain of the laminae.
Some of the genera of Oscillatoriaceap, as
Ainactis (PL 8. fig. 15 b) and Schizosiphon
(fig. 13 d, e), also present a spiral-fibrous de-
composition of their cellulose coats when
old ; and we have seen a spiral marking on
the wall of Cladophora, as described by
Mitscherlich. Agardh has stated that he
detected a complicated spiral-fibrous struc-
ture in the cell-wall of Confervas, extending,
however, from one cell to another ; and he
regards this as a proof of the spiral structure
of primary cell-membrane generally; and

SPIRAL STRUCTURES. [ 714 ]

SPIRILLUM.

says he has likewise detected an analogous
spiral-fibrous structure in the primary cell-
wall of the structures of the Phanerogamia.
The delicate striation of the membranes of
the Confervas and slightly thickened liber-
or parenchyma-cells of many Flowering
plants form a desirable object of investiga-
tion for those accustomed to the delicate
observation of the markings of the valves of
the Diatomaceae. The use of reagents,
such as nitric acid and solution of potash,
boiling, maceration, and other means must
be employed for this purpose, controlled
always by a careful observation of the
structures in their natural state and in diffe-
rent stages of development. It is not im-
possible that all secondary deposits may
prove, as Meyen assumed, to have a fibrous
constitution, and true membrane to be con-
fined to the primary walls. One set of
layers, however, seems always to resist the
endeavour to resolve them into fibrils,
namely those of the horny and fleshy AL-
BUMEN of seeds.

As to the mode of the formation of spiral
secondary deposits, little is certainly known.
Criiger attributes them to spiral circulation
of the secreting protoplasm over the cell-
wall in the position of the future fibres ;
but this is a somewhat speculative notion.
Others have asserted that they are formed
by gradual collocation of visible granules ;
this is certainly an error. We have observed
the gradual formation of the spiral band
in the elater of Marchantia, where it is at
first a faint spiral trace with indistinct
edges ; as it grows thicker, the edges become
more and more defined ; and it is produced
originally in the exact position and pattern
which it subsequently retains.

The actively moving spiral filaments or
SPERMATOZOIDS of the Ferns, Mosses, Cha-
racese, &c. have nothing in common, ex-
cept the spiral form, with the structures de-
scribed in this article ; they belong to the
protoplasmic structures or cell-contents, as
is also the case with the spirally-arranged
green contents of SPIROGYRA ; while this
article refers exclusively to cellulose struc-
tures belonging to the cell-wall.

See also CELL, Vegetable; SECONDARY
DEPOSITS ; PITTED STRUCTURES ; and TIS-
SUES, Vegetable.

BIBL. General works on Vegetable Ana-
tomy ; Schleiden, Ann. N. H. vi. 35, 1839 ;
E. Quekett, Tr. Mic. Soc. i. 1 ; Ann. N. H.
xv. 495 ; Mohl, Verm, Schrift. 285, Ann. Sc.
Nat. 2. xvi. 242; Veg. Cell, 14; Agardh,

Cell. Vegetal. 1852 ; Criiger, Sot. Zeit. xii.
57, 833, xiii. 601 ; Caspary, Sot. Zeit. xi.
801; Tre"cul, Ann. Sc. Nat. 4. ii. 273;
Schacht, Pflanzenzelle, 1852 ; Sot. Zeit. viii.
697 ; Unger, Linncea, xv. 385 ; Spencer,
Linn. Tr. xxv. 405 ; Hofmeister, Handb. Sot.
i. ; Sachs, Sot. 22.

SPIRILLI'NA, Ehr.— A doubtful genus
of marine Infusoria, of the family Arcellina.

Char. Shell siliceous, porous, forming a
flat spiral. S. vivipara. Shell microscopic,
hyaline, smooth, containing numerous em-
bryo shells. Found in America. (Ehren-
berg, Abh. Berl. Ak. 1841, 402, 422.)

SPIRILLI'NA, Ehr., Rupt. Jones.— A
genus of Rotaline Foraminifera, near Pulvi-
milina.

Char. Shell hyaline, consisting of a single
elongated chamber, coiled into a flat close
spiral ; orifice simple, as wide as the tube.

Two recent British species, S.perforata
(PI. 24. fig. 5), and margaritifera ; also some
fossil (Jurassic and Tertiary).

BIBL. Williamson, Rec. For. 91; Car-
penter, For. 180 ; Parker and Jones, Ann.
^#.4.^.386; ix. 221.

SPIRIL'LUM, Ehr.— A genus of Schizo-
mycetous Fungi.

"Char. Consisting of a colourless, tortuous
or cylindrical spiral filament.

These very minute organisms, found in
infusions and decomposing liquids, are very
interesting objects on account of the re-
markable character of their corkscrew-like
movements. They multiply by transverse
division, separating into two portions while
in motion. They are jointed or septate, but
the joints are not alwavs easy of detection.
They are insoluble in boiling potash. Their
structure is best examined when they are
preserved in a dry state. They are appa-
rently related to the Oscillatoriaceous Algae,
but are very different from Spirulina, with
which they have been compared. Spiril-
lum bryozoon consists of the spermatozoids
of Mosses.

Like the other Schizomycetes, they pro-
duce decomposition in organic liquids. A
species of Spirocliceta is supposed to be the
cause of relapsing fever, and occurs also in
certain purulent discharges.

8. tenue (PI. 7. fig. 17/).> Filament
slightly tortuous, indistinctly jointed ; spiral
of three or four turns ; movement active ;
length 1-1000" ; diam. 1-12,000".

8. undula (PI. 17. fig. 17 g). Filament
very tortuous, jointed; spiral of one or one
and a half turns ; length 1-1500" ; diam.

SPIROCHJETA.

[ 715 ]

SPIROGYRA.

1-120,000". Perty describes a red and a
black variety.

S. volutam (PI. 7. fig. 23). Filaments
very tortuous, distinctly jointed, with a
cilium at each end ; spiral of three, four, or
more turns; length 1-1400"; diam. 1-14,000".

S. plicatik (Spirochceta plicatilis, Ehr.)
(PL 7. fig. 22). Filament very long, flexible ;
coils numerous ; movement undulating ;
length 1-180" ; diam. 1-12,000".

BIBL. Ehr. Inf. 84; Dujard. Inf. 223;
Rabenht, Aly. ii/72.

SPIROCH^ETA, Ehr. — 8. plicatilis =
Spirillum plicatilc.

SPIROCHO'NA, Stein. — A genus of
Peritrichous Infusoria, family Vorticellina.

S. gemmipara (PL 32. fig. 35) is found
upon the branchial plates of Gammarus
pulexj where also its remarkable Acineta-
form (fig. 36) occurs.

S. Scheutenii is met with upon the feathery
setae arising from the terminal joints of the
post-abdominal legs of Gammarus.

S. tintinnabulwn, on 7V#on-larv86.

BIBL. Stein, Inf. ; Clap, et Lachm. Inf.
132; Kent, Inf. 660.

SPIRODIS'CUS, Ehr.— Under the name
S. fulvus, Ehrenberg places among the In-
fusoria, in the family Vibrionia, a brownish
organism, consisting of a short discoidal or
much- flattened helical spiral, 1-1200" in
diameter, and found in Siberia. It exhi-
bited a slow movement. Ehrenberg's figure
greatly resembles that in PL 40. fig. 34 (the
upper two), without the cilia, and magnified
200 instead of 400 diameters. (Ehr. Infus.

Fig. 668.

>PIROGY'RA (Zygnema, Agardh in
part) (fig. 668). — A genus of Zygneinacese
(Confervoid Algaa),
mostly very elegant,
and all very interest-
ing on account of their
structure and modes
of development. They
are green filaments,
floating unattached in
standing fresh water.
They consist of jointed
tubes — that is, rows of
cylindrical cells, some-
times of considerable
size, in the interior of
which the green co-
lou~attSr is a,- S'»^™T
ranged in one or more mamenta conjugating,
spiral lines running Magnified 200 diameters, j

round the walls, these

spiral lines presenting bright points at inter-
vals along their course (PL 9. figs. 17, 26, 27).
The green lines consist of bands of proto-
plasm coloured by chlorophyll. The bright
points are in some stages composed of
globules of similar substance ; but generally
they are occupied by starch-granules im-
bedded in the protoplasm j smaller starch-
granules also occur at certain stages
throughout the green band. A remarkable
lenticular nucleus is also present, suspended
in the centre of the cell by threads of proto-
plasm running out to the primordial utricle
lying against the cell-wall. Sometimes this
nucleus is placed with its faces towards the
side wall (S. nitida, PI. 9. fig. 26) ; sometimes
it appears to be placed with its faces
looking up and down, as it presents the
appearance of a narrow ellipse when seen
sideways (S. pettucida, PI. 9. fig. 27). The
laminated structure of the cell-walls is also
curious, but will be better understood after
a sketch of the mode of development.

The attractive appearance of the Spiro-
gyra and the easily observed phenomenon
of conjugation have caused much attention
to be paid to this genus ; and many points of
their history have been determined. The
cells composing the filaments all multiply
simultaneously when the plant is growing,
each becoming twice its length and divided
into two. It has been certainly observed by
Braun and Priugsheim that the division
is preceded by a division of the nucleus.
From this interstitial mode of growth it is
evident that the walls of the cells of plants
actively vegetating must soon become com-
posed of a number of layers belonging to di-
stinct generations of cells. Thus, supposing
we have an original cell «, this encloses its
progeny, two cells «2 & b ; and when these
divide again and come to enclose respect-
ively a3 & .c and b'2 & d, the parent cell «,
stretched to four times its original length,
still encloses the whole. The laminae be-
longing to the respective generations do not
become very intimately blended; for by ma-
ceration we may cause the outer membranes
to soften and dissolve, and set free the
younger cells intact. The older membranes
seem to have become thinner by stretching,
or by solution, midway between their septa,
since on maceration we may often see them
give way in the middle, and the young cells
slip out* from them, leaving them as short
hyaline tubes with a diaphragm in the mid-
dle. The ends of the cells of some species
present a curious appearance, which might

SPIROGYRA.

[ 716 ]

SPIROGYRA,

be compared to the "punt" of a bottle,
produced by a circular fold thrown in from
the cross septum. It is attributed to the
excessive growth of the membrane of the
young cells, confined in space by the outer
parent-membrane. The filaments of Spiro-
gyra are consequently very instructive in
reference to vegetative cell-formation. In
some cases the half-dissolved parent-cell
membranes form a delicate but well-
defined gelatinous coat on the tube (PI. 9.
fig. 27s).

The reproduction of this genus exhibits,
besides the proper conjugation, other phe-
nomena, the import of which is not yet fully
determined. The conjugation itself has been
observed by almost every microscopist. It
consists essentially in the production of
papillary elevations on the contiguous walls
of the cells of two filaments lying side by
side, the growth of these papillae until they
come into contact, and their coalescence
so as to form a canal of communication be-
tween the two cells (fig. 668 ; PI. 9. fig. 18).
When this is accomplished, the contents of
one of the cells (the contents of both having
meanwhile lost their characteristic arrange-
ment on the cell-walls) pass through the
cross tube into the other cell, when the
contents of both become blended and form
an ellipitical free body (PL 9. fig. 18), which
acquires cellulose integuments and becomes
a spore or zygospore, lying free in the parent
cell. This process is accompanied by the
death of the parent filaments, conjugation
often taking place in the majority of the
cells : the spores are sometimes set free by
decay of the parent cell-wall ; but very often
the latter remains undissolved until the
germination of the spore (PI. 9. fig. 19).
A modification of this mode of conjugation
(PI. 3. fig. 24), occurs in some cases appa-
rently as an abnormal process; for it has
been observed (Braun) taking place in species
which conjugate as above. It occurs in single
filaments 'in which two contiguous cells
produce papillae at the adjoining ends,
growing towards each other and coalescing,
the contents of one of the cells thus passing
into the next cell of the same filament.
Braun calls this "chain-like" conjugation,
in contradistinction to the " ladder-like "
conjugation above described. As the two
forms occur associated, Kiitzing's genus
Ehynchonema and others founded upon this
are of doubtful value.

The ripe spore or zygospore forms an
elliptical body enclosed in three membra-

nous coats, the outer of which is of deli-
cate texture and separated by an interval
from the next, which is brownish and of
firm texture. The inmost coat or true
spore-membrane, is again delicate. The
spores appear to rest through the winter
| after they are formed, and to germinate in
| spring, in which process the middle coat
j of the spore splits at one end, longitu-
dinally, opening by two valves to allow the
inner to grow forth, which bursts through
the outermost sac, in the form of a tube
(PI. 9. fig. 19) which soon acquires the
characteristic appearance of the parent
plants. The contents of the spore are brown
and homogeneous during the stage of rest
(fig. 21) ; in germination they become green
again, and arrange themselves in the spiral
bands (fig. 22), which become more distinct
as the cell elongates.

Certain other occurrences take place in
the cell-contents of the Spirogyrce, the rela-
tion of which to the reproduction is not so
clear as the above. In filaments in an un-
healthy condition, about to decay, such as
are often seen when a collection of them is
placed in a jar of water to keep for exami-
nation, it is not uncommon to see the green
contents gradually lose their spiral arrange-
ment and break up into a number of globular
portions (PI. 9. fig. 28) j we have sometimes
observed these rolling over slowly in the
cell. In one case we have observed the
contents converted into sixteen distinctly
organized biciliated zoospores (PI. 9. fig. 20),
differing only from the ordinary zoospores
of the Confervoids in the almost total
absence of colour. They were somewhat
crowded in the cell, and moved lazily about
in it, the cilia vibrating. It is still more
common to observe the contents of decayed
filaments converted into encysted globules
(PI. 9. figs. 24, 25), which appear to be
a kind of resting-form of the zoospores.
These globules, which have a tough spinulose
coat, have been observed by Pringsheim
as produced from the contents both of
ordinary cells, and abnormally ? from the
contents of a large spore (PI. 9. fig. 23) : the
latter case might give colour to the idea that
this was a sporange, had not its germination
been observed. Pringsheim has further
noticed that actively moving zoospores are
produced from the small encysted bodies ;
perhaps these may fulfil an antheridial
function. Carter has observed in the cells
of Spirogyra the bodies constituting the
genus Pythium, and apparently connected

SPIROGYRA.

[ 717 ]

SPIRORBIS.

with the zoospore-like bodies just described
(see PYTHIUM).

The species of Spirogyra have been
greatly multiplied by authors. The pecu-
liar fold projecting from the septum appears
to us to depend upon age and activity of
growth ; and the length of the joints de-
pends greatly on the stage of growth, as
they continually divide into two equal parts.

Spiral band single.

S. tenuissima. Vegetating filaments 1-3000"
in diani. ; joints four or five times as long
as broad ; spiral band open ; spore oblong-
elliptical (Hassall, pi. 32. figs. 9, 10).

S. longata. Filaments about 1-1000" in
diam. ; joints six or eight times as long ;
spiral lax, spores oblopg-elliptical (Hass.
pi. 31. fig. 394).

S. injlata (S. gastroides, Kiitz.). Fila-
ments 1-1680" in diam. ; joints four or five
times as long ; turns of spiral about five ;
fertile cells ventricose ; spores oblong-
elliptical (Hass. pi. 32. figs. 6, 7).

S. communis (fig. 668). Filaments 1-1440
to 1-2000" in diam. ; joints two or three
times as long ; turns of spiral four, broad ;
spores elliptical (Hass. pi. 28. figs. 5, 6).

S. quinina (PI. 9. fig. 17). Filaments
1-600'' in diani. ; joints once and a half or
twice as long; turns of spiral broad and
dense ; spores elliptical (Hass. pi. 28. fig. 2).
Varies in the length of the joints, which are
sometimes twice to seven times as long.

Spiral bands two.

S. decimina. Filaments 1-720" in diam. ;
joints two to foui' times as long; spiral
bands lax, crossing so as to present the
appearance of the letter X (IHiss. pi. 23.
figs. 3, 4).

S. elongata. Filaments 1-1320 to 1-1200"
in diam. ; joints ten times as long; bands
lax (Berkeley, Gkanings, 12, fig. 2).

Spiral bands numerous.

S. nitida (PI. 9. fig. 26). Filaments
1-360' ' in diam. ; joints twice or three times
as long ; bands four, dense, closely veiled ;
spores elliptical (Hass. pi. 22. figs. 1, 2).

S. maxima. Filaments 1-200 to 1-300"
in diani.; joints equal, once and a half or
twice as long; bands lax; spores globular
(Haas. pis. 18, 19).

S. bellis. Filaments 1-400" ; joints equal
or twice as long ; bands two or three, lax ;
spores rounded; var. 8, spirals condensed
(Hass. pi. 24).

S. pellucida (PL 9. fig. 27). ^ Filaments
1-840" in diam. ; joints four or six times as
long ; bands lax and slender ; fertile cells
ventricose ; spores globose (Hass. pi. 25).

& rimilaris. Filaments 1-2040" in diam. ;
joints three or four times as long; spiral
bands four, broad, dense (Hass. pi. 27).

S. curvatum (Sirogonium stictitum and
breviarticulatum, Kiitz.). Filaments 1-720"
in diam. ; joints four or five times as long ;
bands three or four, slender ; conjugation
direct, without a cross branch, approaching
Mougeotia. (Hass. pi. 26. figs. 1, 2.)

BIBL. Hassall, Alg. 135; Kiitzing, Sp.
Alg. 437, Tab. Phyc. v. ; Pringsh. Flora,
xxxv. 465, Ann. N. H. 2. xi. 210 ; Braun,
Verjilngung, Ray Soc. ; Vaucher, Conferves,
37 ; Agardh, Ann. Sc. Nat. 2. vi. 197 ;
Rabenh. Alg. iii. 232 ; Carter, Ann. N. H.
1880, vi. 207 ; Petit, Spirog. of Paris,
1881.

SPIROLI'NA, Lamk. (SPIBULINA, Ehr.).
— Restricted. The long, narrow, crozier-
like modifications of Peneroplis (P. (Sp.)
austriaca, PI. 23. fig. 12) come under this
title. Fossil and recent.

BIBL. D'Orb. For. Foss. Vien. 137 ; Car-
penter, Phil. Tr. 1859, 10 ; Parker, Jones,
and Brady, Ann. N. H. 3. xv. 230.

SPIROLOCULI'NA, D'Orb. — A sub-
genus of Miliola, among the Porcellaneous
Foraminifera.

Char. Shell regular, equilateral, com-
pressed, oblong, oval, or elongated ; cham-
bers concentric on two opposing faces, in the
same plane, not embracing, all apparent and
with simple cavities ; orifice single, situated
alternately at the two ends of the longitu-
dinal axis, simple or with a tooth, frequently
prolonged into a tube.

% planalata (PI. 23. fig. 7). Many
species, recent and fossil.

BIBL. D'Orb. Ann. Sc. Nat. vii. 298;
Williamson, Rec. For. 82 ; Carpenter, For.
77 ; Parker, Jones, and Brady, Ann. N. H.
4. viii. 248.

SPIROM'ONAS, Perty.— A genus of
Flagellate Infusoria.

Char. Body leaf-like, compressed, rounded
at both ends, and rolled spirally ; with one
or two flagella.

S. volithilis= Cyclidium distortum, Duj.
Kent describes other species. (Perty.
Lebensf. 171 : Kent, Inf. 297.)

SPI'ROPLEC'TA, Ehr. See TEXTULABIA.

SPIROR'BIS, Daudin, Lamk.— A genus
of Annulata, order Setigera.

The elegant little milk-white flat spiral

SPIROSTOMUM.

[ 718 ]

SPLACHNACE^E.

shells of S. naidiloides (communis) (PI. 36.
fig. 29) are frequently met with upon Fucus
serratus, &c. The animal has six pinnate bran-
chial filaments and a pedunculate operculuna.

SPHtoS'TOMUM, Ehr. — A genus of
Heterotrichous Infusoria, family Bursarina.

Char. Body ciliated all over, oblong or
cylindrical and elongated, or flat ; mouth
spiral, with neither teeth nor a tremulous
lamina ; anus posterior ; freshwater.

S. ambiguum (PL 31. figs. 77. 78). Body
cylindrical and elongated, colourless, ob-
tuse in front, truncate behind, prolonged
anteriorly beyond and above the mouth ;
length 1-12".

S. teres. Body linear-fusiform ; length 1-60' '.

BIBL. Ehr. Inf. 332; Dujard. Inf. 514;
Clap, et Lach. Inf. 231.

SPIROT^E'NIA, Brdb. — A genus of
Desmidiacese.

Char. Cells single, elongated, cylindrical
or fusiform, straight, entire, not constricted ;
endochrome spiral.

Division oblique. In one species the
endochrome is spiral at first, subsequently
becoming uniform.

S. condensata (PI. 14. fig. 59). Endo-
chrome forming a single broad band ; length
1-208" ; common.

S. obscura. Endochrome at first forming
several spiral threads, afterwards uniform ;
length 1-240".

BIBL. Kalfs, Desmid. 178 ; Archer, Qu.
Mic. Jn. 1867, 186 ; Rabenhorst, Alg. iii.
145.

SPIRULI'NA, Link.— A genus of Oscil-
latoriaceae (Confervoid Algae), consisting of
minute spirally coiled geeen filaments im-
mersed in a colourless gelatinous matrix,
and having an oscillating motion ; forming
extensive strata in lakes, brackish water,
&c. The intimate structure and develop-
ment of these curious organisms are not yet
well understood; they are supposed to
increase by the filaments breaking across :
in some the filament appears continuous;
in others it has striae, like the Oscillatorice,
appearing beaded when badly defined.

S. Jenneri (PI. 7. fig. 16). Filaments
with striae, 1-6000" in diameter, usually of
eight or ten coils, forming a thin aeruginous
stratum.

8. oscttlarioides (PI. 7. fig. 15). Fila-
ments not striated ; coils 1-7200" in diani. ;
lax. Among Oscillatorice in stagnant pools.

BIBL. Kiitzing, Sp. Alg. 236; Hassall,
Alg. 277, pi. 75 ; Harvey, Mar. Alg. 229,
pi. 27; Phyc. -Br.pl. 105; Ralfs, Ann. N.H.

xvi. 308, 2. viii. 205; Cohn, Nova Acta,
xxiv. ; Rabenht. Alg. ii. 90.

SPLACHNA'CE^E.— A family of Funa-
rioideae (Acrocarpous operculated Mosses),
of broad and densely tufted habit, mostly
found upon dung, with a very much branched,
loosely-leaved stem (fig. 669). Inflorescence
hermaphrodite, dioecious, rarely monoecious.
Antheridial flower a capituliform, terminal
bud. Antheridia large, club-shaped, rather

Fig. 669. Fig. 670.

Splachnum vaseulosum.
Fig. 669. Nat. size.

Fig. 670. Eipe capsule open, dried, and the apophysis
shrivelled. Magnified 20 diameters.

Fig. 671. Fig. 672. Fig. 673.

Splachnum vaseulosum.

Fig. 671. Calyptra. Magnified 20 diameters.

Fig. 672. Young capsule and apophysis. Magnified
20 diameters.

Fig. 673. Vertical section of an unopened capsule with
its spongy apophysis. Magnified 20 diameters.

curved. Archegonia narrow, long-apicu-
late. Peristome, if present, of regularly

SPLACHNACE^E.

[ 719 ]

SPLEEN.

lanceolate, neither obtuse nor trabeculate,
twin, rufescent, rather fleshy teeth. Colu-
mella ordinarily projecting (fig. 670). Cap-
sule on an apophysis (fig. 673), mostly fur-
nished with stoinates.

British Genera.

(Edipodium. Calyptra soft, longish-nar-
row, split almost to the summit, obtuse,
somewhat lacerated at the base. Capsule
subglobose, loosely reticulated, soft, with a
very long colluin arising from a gradually
thickened fruit-stalk, the mouth naked.
Columella dilated at the apex. Inflores-
cence monoecious.

Tetraplodon. Calyptra smallish, hood-
shaped, split to the middle, operculate,
delicate. Capsule apophvsate, oval-cylin-
drical. Apophysis obconical, obovate, or
subovate. Columella scarcely dilated at
the apex. Peristome of sixteen double teeth
in fours, lanceolate, formed of two rows of
cells, connate in pairs at the base, reflexed
when dry, erect and incurved when moist,
much shorter than the capsule. Antheridial
flower sessile in the axil of a leaf, or termi-
nal on a little special branch, in a capituli-
forrn bud.

Tayloria. Calyptra inflatedly conical,
erect, split at one side, constricted at the
base, lacerated around the margin. Peri-
stome arising below the orifice of the cap-
sule, of sixteen or thirty-two teeth j teeth
single, approximated in pairs or coherent,
often very long ; when moist incurved and
involuted, when dry (in the ripe capsule)

Fig. 674.

reflexed, appressed to the capsule or tortu-
ously bent down; very hygroscopic. Inflo-
rescence monoecious. fcolumella mostly
free, exserted from the ripe capsule, flattish*-
apiculate.

Dissodon. Calyptra inflatedly conical,
erect, slit at one side, constricted at the
base and torn or erose. Peristome arising
at the orifice of the capsule. Teeth thirty-
two, connate, in eight bigeminate or sixteen
geminate teeth, lanceolate, smooth, trans-
versely articulate, connivent into a depressed
cone when moist, subincurved when dry.
Inflorescence perfect or monoecious. Colu-
mella included or exserted, flattish.

Splachnum. Calyptra conical, rather
small, entire or slit here and there at the
base. Peristome of sixteen teeth, composed
of a double row of cells, lanceolate, largish,
yellowish, approximated in pairs and to
some extent conglutinated, when dry re-
flexed and appressed to the capsule, when
moist erect and incurved at the apex. In-
florescence dioecious, rarely monoecious.
Columella ordinarily emerging, capitate.

SPLACHNUM, Linn. — A genus of
Splachnacese (see above). & amputtaceum
is not uncommon on the dung of animals on
bogs, is a very handsome moss, with purple
or red capsules. S. vasculosum (figs. 669-
673) is less common, occurring only in high
mountain districts.

SPLEEN. — This organ appears to occur
exclusively in the Vertebrate, but is not
found in the Leptocardia and Myxinoids.
The spleen is covered externally by the

Fig. 675.

Fig. 676.

Fig. 674. Natural size. Portion from the middle of the spleen of an or, washed ; showing the bands and their
arrangement.

Fig. 675. Peculiar fibres from the pulp of the human spleen, belonging to the microscopic trabeculee. Magnified
350 diameters.

Fig. 676. One of the same enclosed in a cell. Magnified 350 diameters.

SPLEEN.

[ 720 ]

SPLEEN.

peritoneum, except at the hilus, where the
vessels are connected with it.

Beneath the peritoneal tunic is a thin,
semitransparent, firm, fibrous coat, which at
the hilus accompanies the vessels, and forms
sheaths around them.

The spleen is traversed by fibrous bands
or trabeculge (fig. 674), which arise from
the inner surface of the fibrous coat and
from the outer surface of the vascular
sheaths, and, being connected with each
other, form a number of irregular meshes
or areolee, in which are situated the splenic
corpuscles and the spleen-pulp. In reptiles
they form stellate expansions, their connec-
tive tissue becoming infiltrated with lyniph-
corpuscles; and the connective tissue in
this modified form occupies all the inter-
spaces of the proper parenchyma of the
organ.

The fibrous coat and the trabeculae consist
of ordinary connective tissue, with mostly
parallel fibres, traversed by networks of fine
elastic fibres, which become continuous with
the coats of the veins. In certain animals,
as the dog, cat, pig, &c., the fibrous coats
and trabeculas contain also unstriped mus-
cular fibres. These do not occur in man,
unless they are represented in the micro-
Fig. 677.

scopic trabeculae by peculiar wavy fibres,
about 1-500" in length, with lateral or
stalked nuclei (fig. 675). Some of these
are found enclosed in cells (fig. 676), from
which they become liberated by the action
of water.

The splenic or Malpighian corpuscles

f. 677) are white rounded bodies, imbed-
in the spleen-pulp, and attached to the
smallest arteries. They vary in size from
1-120 to 1-36", and cannot always be de-
tected. They are either placed upon the
sides of the arterial branch, or situated in
the angles of their bifurcation.

The splenic corpuscles consist of an enve-
loping membrane (fig. 678 a) composed of
connective tissue with fine reticular elastic
fibres, and derived from the arterial sheath.
They are traversed by capillaries and filled
Avith a tenacious grey parenchyma. The
parenchyma consists of cells 1-3000" in
diameter, containing one or two nuclei, and
free nuclei (fig. 104, p. 138). Sometimes
the cells contain globules of fat or blood-
corpuscles j and occasionally free blood-cor-
puscles are met with. When the splenic
corpuscles undergo amyloid degeneration,
they produce the so-called sago-spleen.

"the splenic pulp forms a soft reddish

Fig. 678.

Fig. 677. Portion of a small artery from the spleen of a dog, with one of the branches covered with Maloiehian
bodies. Magnified 10 diameters.

Fig. 678. Malpighian corpuscle from the spleen of an ox. a, wall of the corpuscle; 6, contents; e, wall of the
artery upon which it is situated ; d, its sheath. Magnified 150 diameters.

SPOLVERINA.

[ 721 ]

SPONGIDA,

mass, and consists of three elements — micro-
scopic trabeculse, fibres, or bands, parenchy-
ma-cells, and the smaller blood-vessels — or
of cells and an intercellular substance. The j
trubeculte agree in structure with the larger
ones. The fibres or bands are the termina-
tions of the sheaths of the vessels ; they are
indistinctly fibrous, and free from elastic \
tissue. The parenchyma-cells resemble
those in the splenic corpuscles. Blood-cor-
puscles are found enclosed in cells, from
one to twenty in each, or surrounded by a
transparent substance, their contents exhi-
biting- various changes in colour and con-
sistence. The arteries terminate in elegant
tufts or penicilli, becoming continuous with
a mesh work of capillaries.

The blood-corpuscles from the blood of
the splenic vein frequently contain crystals
of haematoidine.

In the examination of the spleen, the tra-
beculae are best seen after washing away the
pulp with water, the splenic corpuscles by
tearing the spleen or boiling it, either in
the pig or ox. The cells containing blood-
corpuscles must be searched for in the pulp j
unacted upon by water. The muscular fibres
are most evident in the smaller trabeculae,
especially after treatment with dilute nitric
acid (one part to five parts of water).

BIBL. Kolliker, Mik. An. ii. and Todd's
Cycl. An., art. Spleen ; Grav, A. Cooper's
Prize Essay ; Saunders, Goodsir 's Ann. of An.
1851, i. ; Huxley, Qu. Mic. Jn. ii. 1854 ;
Frey, Mikros. ; Miiller, Strieker's Hist, and
the Bibl. therein.

SPOLVERI'NA, Mass. — A genus of
Micro-lichens, parasitic on the thallus and
prothallus of various crustaceous lichens.

Char. Spores 1-2, large, globose-ovoid,
simple, colourless, or yellowish. (Lindsay,
Qu. Mic. Jn. 1869, 344.)

SPONDYLOCLA'DIUM.— A genus of
Deniatiei (Hyphomycetous Fungi), analo-
gous to Arthrobotryum, characterized by the
erect filaments, with whorled multiseptate
spores (PI. 27. fig. 15). (Mart., Fl. erl. 354 ;
Link, Spec. 79; Hoffmann, Fl. germ. ii.
pi. 13.)

SPONDYLOM'ORUM, Ehr.— A genus
of Volvocineae.

S. quaternarium. Cosnobium globose,

composed of 8-12-16 cuneate green cells,
each with a long cilium, and a dorsal red
eye-spot, enclosed in a colourless gelati-
nous envelope (PI. 3. fig. 23). In ditches.
(Pertv, Lebemf. 177; Rabenht. Ala. iii. 98.)
SPONGASTERIS'CUS,Hckl.— A genus

of Radio-flagellate Infusoria, with a silice-
ous perforated carapace. 2 species; marine.
(Kent, Inf. 229.)

SPON'GIDA or PORIF'ERA.— A Class
of Protozoa.

Char. Form variable ; fixed by a kind of
root at the base, or incrusting ; consisting
of a soft gelatinous sarcodic mass, mostly
supported by an internal skeleton, composed
of reticularly anastomosing horny fibres, in
or among which are usually imbedded sili-
ceous or calcareous spicula ; or sometimes
the spicula alone form the skeleton.

The horny fibres forming the skeleton of
sponges, which may be well seen hi any
common sponge, are cylindrical, and vari-
ously united, so as to form a coarse network
with roundish or angular microscopic meshes.
In addition to these generally diffused
meshes or intervals, large (to the naked
eye) rounded apertures or oscula are scat-
tered over the surface of most sponges,
leading into sinuous canals permeating their
substance in every direction ; and between
these are other smaller apertures, just visi-
ble to the naked eye, also the orifices of
canals, which traverse the substance and
communicate with the oscular canals.

In the living sponge, this skeleton is
covered with a glairy or gelatinous, colour-
less, amorphous substance, resembling that
of which Anwebce are composed; the
proportion being variable in the different
genera. This substance appears to be
composed of minute masses, those on the
surfaces being furnished with a long and
slender flagellum, or forming collared
monads; and during life, by means of these,
water entering by the smaller apertures,
and reaching the oscular channels, is ex-
pelled from the oscula in currents, which
may be rendered visible by sprinkling a
little finely powdered charcoal over them.
Hence Clark and Kent refer the Sponges
to the Choano-flagellate order of the Infu-
soria.

The fibres of the common Sponges appear
to be solid under the microscope ; and when
treated with sulphuric acid, they are seen to
consist of two parts, an outer tubular portion,
which is contracted in length by the acid,
and an inner cylindrical thread, which
usually becomes elegantly wavy or spiral,
frequently protruding from the cavity of the
outer portion in broken fibres, and resem-
bling PL 28. fig. 22.

The spicula are of various forms (PI. 45,
lettered figures), and either scattered through

3A

SPONGIDA.

[ 722 ]

SPONGOCYCLIA.

the substance or arranged in bundles form-
ing spurious fibres; sometimes projecting
more or less from the surface (PI. 45. 'fig. 8).
In some sponges they are absent, and in
one genus they are replaced by gravel. The
calcareous spicula exert a much more
powerful action upon polarized light than
the siliceous spicula.

In some sponges, an external membrane
is present ; and this has been observed to
exhibit a reticular or cellular appearance,
from the presence of fine reticular fibres.

Sponges are mostly marine, rarely fresh-
water. In the natural state they often
possess lively colours, which appear in some
instances to arise from the presence of gra-
nules of colouring matter, probably chloro-
phyll, in others from iridescence. They
usually grow in groups upon rocks, shells,
zoophytes, sea-weeds, &c.

Sponges appear to be propagated in four
ways : — by gemmation, from the interior of
the canals ; by the formation of ciliated gem-
mules (swarm-spores) ; by the formation of
true sexual ova ; and by the production of
bodies analogous to " winter-ova."

The ciliated gemmules, which are not of
general occurrence, are yellowish, oval,
narrowed at one end, and covered, except
at this part, by vibratile cilia. They are
mostly formed in spring, and after swim-
ming about for a time, become fixed to some
suitable spot and undergo development.

Of the other reproductive bodies, one
kind consists of roundish or ovate masses
containing spicula and resembling the
parent in structure, either lying loose in its
substance, or adherent to the horny fibres,
and escaping at its death and solution, to
acquire maturity.

The " winter-ova " are round or ovoid
seed-like bodies, with a funnel-shaped de-
pression on the surface communicating with
the interior. At first these lie in a cavity
formed by condensed surrounding substance ;
subsequently a membrane presenting a hex-
agonal reticular structure is formed around
them, upon which a crust of spicula is
afterwards deposited. When expelled from
the body of the parent, they are motionless j
they then swell up, burst, and the minute
locomotive germs escape. These exhibit
Amoeba-like processes, and take on an inde-
pendent life.

The true ova are oval, and scattered
through the general substance ; they have a
distinct outer membrane, with a germinal
vesicle and spot. The spermatozoa have

an oval body and a filament ; they occur in
minute cells, also diffused through the sub-
stance. The germs are ciliated.

Sponges are probably^ nourished by en-
closing Algae &c. in their substance in the
same manner as Amoeba. This has been
seen to take place in the young animals
developed from the winter-ova.

According to the skeleton, the sponges
are divided into three Orders : Myxospon-
yice, in which it is absent (Halisarca); Fibro-
spongice, in which it is horny or siliceous ;
and Caldspongice, in which it is calcareous.

Thread-cells have been found in the
genus Reniera ; and Eimer states that he has
even distinguished in some siliceous forms
something like connective tissue and fusi-
form muscular fibres.

BIBL. Johnston, Br. Sponges ; Bowerbauk,
Br. Spong.) Ray Soc. 1866 ; Huxley, Camp.
Anat.; James-Clark, Amer.Jn.ofSci. 1871 ;
Gray, Pr. Roy. Soc. 1867 ; Lieberkiihn,
Miiller's Archiv, 1856, Ann. N. II. 1868, ii.
236; Thomson, Phil. Tr. 1869, and Deep-sea
Dredging ; Ellers, Sieb.und Koll Zeit. 1871,
xxii. 540; Eimer, Schuttze's Arch. 1872;
Leidy, Amer. Nat. 1870; Agassiz, Butt.
Harvard Coll 1869; Miklucho-Maklay,
Mem. Acad. Petersbourg, 1870; Schmidt,
Spongienfauna Atlan. Geb. 1870 ; Spong.
Kilste Algier, Spong. d. Adriat. Meer. ; Car-
ter, Ann. N. H. 1878, ii. 157 ; ib. 1879, iii.
284, 343 ; ib. 1879, iv. 374 ; Gosse, Mar. Zool.
i. ; Haeckel, Kalkschwiimme,187'^ ; Vosmaer,
Bronn, Klass. $c.t 1882 ; Kent, Inf. 143.

SPONGIL'LA, Lam.— A genus of fresh-
water sponges. Two British species, S.
fluviatilis and S. lactistris.

Found attached to stones, old woodwork,
&c. in still or slowly running waters ; green
or grey. See SPONGIDA.

SPONGIOLES.— Many works on vege-
table physiology still retain the old error
that the extremities of roots are devoid of
epidermis, and that the tissue then presents
an open spongy character, whence the name
of spongioles applied to the absorbing apices
of roots. So far is this from being a correct
account of the conditions, that, in reality,
not only is the surface completely invested
with a continuous epidermis, but the grow-
ing point and principal absorbing surface is
found a little above the absolute extremity,
which is pushed forward by interstitial
growth (fig. 679); See ROOTS.

SPONGOCYC'LIA, Hckl.— A g-enus of
Radio-flagellate Infusoria. Several species ;
marine. (Kent, Inf. 228.)

SPONGOMONAS.

[ 723 ]

SPOREKDONEMA,

Fig. 679.

• "

c D

Longitudinal section of the rootlet of an Orchis.

C, C, Cellular tissue (cambium) in which development
is still going on. FP, Fibro-vascular bundles gradually
becoming organized from above downwards.

Magnified 500 diameters.

SPONGOM'ONAS, Stein.— A genus of
Flagellate Infusoria. Ovate or rounded j
flagella two, equal ; immersed in a gelati-
nous envelope. Four species ; freshwater.
(Kent, Inf. 286.)

SPORAN'GIUM and SPOR'OCARP.—
The term sporangium is applied to the
structure immediately enclosing the spores
of the Cryutogamia. The different forms
and conditions are described under the
classes of Flowerless plants. Abortive spo-
rangia in Ferns, sometimes borne on the
pedicel of the true sporangia, are called spo-
rangiastra. Sporocarp or spore-fruit is the
name given to the capsules or similar organs
which contain the sporanges of the Mar-
sileaceae (see PILULAIIIA).

SPORENDONE'MA, Desm.— A sup-
posed genus of Sepedoniei (more properly
belonging to Saprolegneae). It is a very
common occurrence in autumn to find the
house-fly, dead, adhering to walls, window-
panes, &c., firmly fixed by its proboscis,
and with its legs spread out, thus differing
from dead flies in general, which have the
legs contracted. In about twenty-four
hours after death, a kind of fleshy substance
of a white colour, is found in the form of a
ring projecting between each of the rings,
of the abdomen ; and in a day or two after,

the whole will be found dried, and the
surface of the wall or glass lightly covered
in a semicircle, at about 1-2 to V from the
fly's abdomen, with a cloud of whitish
powder. The whitish fleshy substance is
found on examination to consist of a vast
number of short erect filaments growing
out from the interior of the fly's body, be-
tween the rings ; these filaments contain
large oil-globules, often arranged in a row j
and their having been mistaken for spores
gave origin to the name Sporendonema
applied to this fungus. Cohn has described
its growth somewhat minutely, and chan-
ged the generic name to Empusa, or rather
Empusina, the first of these names being al-
ready occupied. He correctly states that
the vertical filaments terminate in the ab-
domen in a continuous, often branched
tube, and consist therefore of a single tubu-
lar cell. The upper free end, however, be-
comes cut off by a septum ; and the terminal
cell acquires a campanulate form and a
darkish colour ; when ripe, it is thrown off
with elasticity ; and a number of these form
the white cloud above mentioned. Cohn
endeavoured in vain to make them germi-
nate ; and nothing like them was found in
the cavity of the abdomen of numerous
flies in which the filaments were traced in
their earlier stages. From our own obser-
vations, we rather incline to regard them as
peridioles or spore-cases, comparable perhaps
to that of Pitobolus ; or they may be stylo-
spores, like some of those *of the Uredinei,
which after a stage of rest produce an inter-
mediate mycelial structure, and then give
birth to the ripe spores.

The most remarkable point about this fly-
fungus (to which, however, Cohn does not
allude) is the circumstance that, when the
body of the fly with the rings of fungi
freshly developed is placed in water, ACHLYA
prolifera is almost always, if not always,
produced, and apparently from the filaments
which in the air produce the bell-shaped
deciduous body above described. We find
the Achlya with its ciliated zoospores, and
later with its globular sporanges filled with
spores, apparently representing an aquatic
form of the Sporendonema or Empusina.
Cienkowski has recently confirmed the view
that Aclilya is an aquatic form of the present
plant, but Braun denies this ; he states that
he has found a second species of Empusina
on the common gnat (Qulex pipiens).

Sporendonema Casei, Desm., is referable
to TORULA.

3A2

SPORES.

[ 724 ]

SPORES.

BIBL. Berk. Br. Fl ii. pt. 2. 350 ; Fries,
Syst. Myc. iii. p. 435, Sum. Veg. 594 ; Var-
ley, Tr. Mic. Soc. iii. ; Colin, Nova Acta,
xxv. 299 ; Berk, and Broome, Ann. N. H.
2. v. 460 ; Cienkowski, Bot. Zeit. xiii. 801 ;
Braun, Akj. Unicell 105.

SPORES, SPOBULES, SPOBIDIA, SPOBI-

DIOLA, MlCBOSPOBES, MACBOSPOBES, &C. —

A number of nearly connected terms which
are applied to the various organs which
either really or apparently represent, in the
Flowerless Plants, the seeds of the Flower-
ing classes. The names have been mostly
applied with the view of marking slight
distinctions between organs supposed to be
homologous. Of those placed at the head
of this article, the first only should be
retained, the second being merely a useless
diminutive of it, and the third and fourth
being superseded by the more definite no-
menclature now applied to the reproductive
bodies of the Cryptogamia.

It may be desirable perhaps here, if merely
for the sake of explaining the exact meaning
of words constantly used in this work, to
pass in review the various structures com-
prehended under the general name of
Spore.

The definition of the word spore itself, as
commonly used, may be stated thus : — are-
productive body, thrown off by a Flowerless
plant to reproduce its kind, and containing
no embryo at the moment when cast off by
the parent. It is evident from this how lax
is its application.

The highest of the Flowerless plants, the
Marsileaceae and the Lycopodiaceae, produce
two kinds of spore — one destined to produce
sperinatozoids, the other archegonia and
ultimately embryos growing up into new
plants. These are sometimes distinguished
as pollen-spores and ovule-spores or oospores ;
the latter are large sacs with complicated
outer membranes, the former simple cells
with a double coat, like pollen-grains (see

PlLULABIA, ISOETES, and LiYCOPODIACEJE).

The Ferns and the Equisetaceae produce
only one kind of spore, a simple cell with a
double coat, the outer of which is generally
elegantly marked in the former (figs. 232-
236, p. 321), and split up into elastic fila-
ments or elaters in the latter (fig. 205,
p. 300). In germinating, this spore pro-
duces a kind of thallus, the prothallium
(figs. 236-239, p. 321), on which antheridia
and archegonia ultimately appear, and an
embryo is formed, fertilized, and developed
(see FEBNS and EQUISETACEJE).

Fig. 680.

In the above cases the spores are always
formed in sporanges of various kinds, deve-
loped directly from the axis or the leaves
by a process of vegetative growth.

In the Mosses and Liverworts the spores
are mostly of one kind, consisting of a cell
with a single or (generally) double coat, like
a pollen-grain. The spores, unlike those
above-mentioned, are formed in sporanges
which are the product of fertilized arche-
gonia, and more resemble the fruits of
Flowering plants. The spores of Mosses
germinate by emitting the inner coat as a
Confervoid filament (fig. 680), which usually
branches and gives
origin to numerous
stem-buds. The
spores of the Liver-
worts exhibit many
modifications in the
first stages of ger-
mination, as illus-
trated by the ac-
companying figures Spores of a moss germinating.
(figs. 682-684); Magn. 100 diams.

the Marchantiae

and other frondose kinds grow at once into

thalloid fronds (see MOSSES and HEPA-

TICJE).

The systematic position of the Characeae
is perhaps still an open question ; but there
can be little doubt of the analogies between
these red productive bo'dies and those of the
other Cryptogamia. There is no sporange
here, nor apparently any archegonia. The
glolule^ (figs._ 121 & 122, p. 162) produces
antheridia giving birth to spermatozoids.
The nucule (fig. 120, p. 161) appears to be
a spore (see CHABACEJE).

In the Lichens, only one kind of organ
has been termed a spore, namely the repro-
ductive cells formed in the thecae (PI. 37.
figs. 6 & 12), which are known to reproduce
the plant when thrown off by the parent.
Two other kinds of body connected with
the reproduction occur ; these, the gonidia
(PL 37. figs. 2, 3) and the spermatia (see
LICHENS), have fortunately obtained and
preserved distinctive appellations. The
spores are simple cells or septate tubes,
with a double membrane.

In the Algae much confusion still exists,
not only between different kinds of spore,
but even between spores and sporanges;
and this is not easily cleared away, since in
certain cases the organs appear really capable
of serving as one or the other, according
to circumstances; the true spores are

SPORES.

[ 725 ]

SPORES.

always simple cells with a double or triple
coat/

In the Florideae, the characters of the
structures seem pretty clear ; we find spores
(p. 327), TETRASPORES (figs. 248-250),
which appear to represent the gonidia of
the Lichens, and spermatozoids (see FLORI-
DE^E). Among the olive-coloured sea- weeds
(Fucoids), the FUCACEJE andDiCTYOTACE^E
produce spores and spermatozoids ; but in
the majority of the families, only a totally
different mode of reproduction is known.
The plants produce ovate sacs, commonly
called spores, and chambered filaments ;
from both are discharged actively moving
ciliated cells, corresponding exactly to the
ZOOSPORES of the Confervoids. Thuret re-
gards the oosporanges a'ld trichosporanges
(fig. 458, p. 501), as he called these sacs and
filaments respectively, as merely different
forms of one kind of structure. But it
seems possible thac true spores may be dis-
covered, even indeed that the oosporanges
may be parent cells sometimes of zoospores
and sometimes of spores.

Fig. 682.

Fig. 683.

In the Confervoids we find true spores in
very many cases, pro-
duced generally after Fig. 681.

some process of ferti-
lization or of CONJU-
GATION, in special
cells (fig. 668, and
PI. 9. figs. 16 & 18 :
PI. 10. figs. 1-5). But
the " spores " thus
produced, while they
sometimes germinate
into new filaments,
also sometimes pro-
duce numerous bodies

Of different kinds,

connected in some

way with reproduc- spores.

tion ; this is the case Magn. 200 diams.

in SPIROGYRA (PI. 9.

fig. 23), perhaps also in CLOSTERIUM and

other instances. Besides the spores proper,

we have also in this family, ZOOSPORES

— the actively moving ciliated bodies which

are regarded as gonidia and are further di-

Fig. 684.

*odulariaspuinigera.

Pellia epiphylla. Preissia commutata. Blasia pusilla.

Spores of Hepatic® germinating. Magnified 200 diameters.

vided into macrogonidia and microgonidia
(HYDRODICTYON), the latter of which
may perhaps have the function of sperma-
tozoids (see SPH^EROPLE A andVAUCHERiA).
In the Fungi the greatest confusion exists
in the nomenclature. The Agarics and their
congeners produce free naked cells at the tips

of short filaments, whence they ultimately
fall off, to reproduce the plant ; these are
called spores or sporules, or distinctively
BASIDIOSPORES (figs. 53-5o, p. 92). There
is no essential difference between them and
the spores produced by the Hyphomycetes,
either singly or in rows or capitula (Bo-

SPORES.

[ 726 ]

SPOROCHISMA.

TRYTIS, figs. 77, 78, p. 116 ; figs. 685, 686;
and PI. 26. figs. 5, 6, 15, 16) at the ends of

Fig. 685.

Fig. 686.

Fig. 687.

Fig. 685. Mystrosporium Stemphylium, Corda (Stem-
phylium, Fries). Magn. 200 diams.

Fig. 686. Stachyobotrys atra. Fertile filament with
heads of acrogenous spores. Magn. 200 diams.

Fig. 687. A head of spores. Magn. 500 diams.

erect filaments ; these again appear to pass
almost insensibly into the conidia or repro-
ductive cells produced by the breaking-up
of the mycelium, either wholly or in part,
into free cells capable of continuing the
growth (ToRULA, PI. 26. fig. 7, and OIDIUM,
fig. 8) : on the other hand, the spermatia
(figs; 2, 0, 4), such as occur in some of the
Coniomycetous forms of the Pyrenomycetous
and Discomycetous Fungi, are closely re-
lated, as far as structure goes, to the conidia
of Torula &c. and the spores of the Hy-
phomycetes; while the stylospores of the
UREDINET and TREMELLIJN'I produce bodies
resembling them, and still more like the
basidiospores of the Agariciiii. The stylo-
spores, another free form of spore, may be
regarded probably as compound organs,
formed of a row of cells contained in a
persistent parent cell : it is surmised that
they are merely metamorphosed asci (see
SPHJERTA and STILBOSPORA, PI. 26.
figs. 25-28) ; yet their mode of occurrence
would lead to the idea that they are a
distinct kind of organ. Lastly, we have
the ascospores or thecaspores (fig. 42, p. 78),
closely resembling those of the Lichens,
consisting of free cells with a double coat,
developed free in the cavity of a parent cell
or sac. In the British Flora the terms spo-
rule and sporidium are used synonymously
in the sense of spore, and are applied to
basidiospores, ascospores, stylospores, and
to the bodies (found in Cytispora, Tuber-
cularia, &c.) called by Tulasne spermatia.

The term sporidiola is applied apparently to
nuclei or granular masses occurring in the
cavities of spores, or to the separate portions
of contents of imperfectly septate stylo-
spores.

The sporangia of Diatomaeese are some-
times called Auxospores.

With regard to the homologies of the
above structures, the spermatia are supposed
to represent spermatozoids ; the conidia are
regarded as corresponding to gonidia of
Lichens j the stylospores are also connected
with these through the medium of the
tetraspores of the Florideae.

In conclusion, a reference may be made
to descriptions and figures like those given
(figs. 688, 689) of free spores resting on the
matrix and among the filaments. Such
characters are totally out of date in the

Fig. 688.

Fig. 689.

Fig. 688. Leptotrichum glaiicum. Free spores among
the filaments of the matrix. Magn. 200 diameters.

Fig. 689. Fusarium herbarum. Free spores resting
on the matrix. Magn. 200 diameters.

present state of science, and simply serve
as indices of points requiring further in-
vestigation.

BIBL. See the heads of the classes of
Cryptogamic Plants.

SPORIpES'MIUM.— A genus of Toru-
lacei (Coniomycetous
Fungi), growing upon Fig. 690.

bark,' wood, &c. (PI.
27. fig. 12).

The character of
the spores seems to

vary in different spe- s id;smium paradoium.
cies ; sometimes they
are simply septate,
sometimes cellular
(fig. 690).

See TORULACEI.

SPOROCHIS'MA,

Spores sessile on the

matrix.
Magn. 200 diams.

Berk, and Br.— A

SPOROCHNAOE.E.

[ 727 ]

SPUMARIA.

genus of Toriilacei (Coniomycetous Fungi),
containing one species, S. mirabile, forming
a black velvety stratum on rotten beech
wood. See TORULACEI.

SPOROCHJSTA'CE^E — A family of Fu-
coidea?. Olive-coloured, inarticulate sea-
weeds, whose unilocular and septate spo-
ranges are attached to external jointed
filaments, which are either free or compacted
together into knob-like or warty masses.

Synopsis of British Genera.

* Sporanaes attached to pencilled filaments
is*n ing from the branches (Arthrocla-
dieae).

Desmarestia. Frond solid or flat, di-
chotomously branched.

Artkrocladia. Frond traversed by a jointed
tube, filiform, nodose.

Xtihphora. Frond filiform, tubular or
solid, branched ; sporanges arising from
necklace-shaped filaments collected in wart-
like groups upon the frond.

** Sporanges produced in knob-like receptacles
composed of whorled filaments compacted
together (Sporochneae).

Sporochnus. Receptacles lateral, on short
peduncles.

Carponntra. Receptacles terminal, at the
tips of the branches.

SPOROCH'NUS, Ag.— A genus of Spo-
rochnaceae (Fucoid Algae), containing one
British species, S.pedunculatus (PI. 4. fig. 1),
having a filiform, solid, cellular main axis

(containing a central cord of dense tissue), '
bearing long slender branches arranged in a
somewhat pinnate manner and clothed at
intervals with elliptical fertile ramules, con- I
sisting of an axis densely covered with whorl-
ed horizontal branching filaments bearing
ovoid sporanges, and terminating in a decid-
uous pencil of byssoid filaments. Main stem
6 to 8" long, olive-brown, changing to yel-
low-green on exposure.

BIBL. Harvey, Mar. Alg. 25, pi. 5 A ; Gre-
ville, Alg. Br. pi. 6 ; Thuret, Ann. Sc. Nat.
3. xiv. 238.

SPOROC'YBE, Fries.— A genus of De-
matiei (Hyphomycetous Fungi), growing j
on dead sticks, decaying stems, &c., forming '
usually a blackish stratum. Several British i
species are recorded. They have a rigid,
septate, simple or branched peduncle, ending |
with a capitate head clothed with spores
(figs. 691, 692). This genus is synony-
mous with Periconia, Corda. Periconia,
Tode, is an obscure form.

Fig. 691.

1

Fig. 692.

Sporocybe bulbosa.

Fig. 691. Stratum upon a stick. Nat. size.
Pig. 692. Two fertile peduncles, crowned with heads
of spores. Magnified 100 diameters.

BIBL. Berk. Br. Flor. ii. pt. 2. 333 ; Ann.
N. H. vi. 433, pi. 13 ; Fries, Sum. Veget.
467 ; Syst. My col. iii. 340.

SPOROT'RICHUM, Link.— A genus of
Mucedines (Hyphomycetous Fungi), grow-
ing on decaying vegetable substances, dung,
&c. The ibrms referable to this genus,
according to the character, include a very
heterogeneous assemblage ; indeed the cha-
racter which omits the nature of the original
attachment of the spores, is worth nothing.
Fries has separated a genus TBICHOSPO-
BIUM, including a number of species with
distinctly acrogeiious spores ; this includes
S. niyrum and S. geochroum of the Brit.
Flora. The remainder are placed by him
among the Sepedoniei, under Sporotrichum
and another genus which he calls Physo-
spora. These genera are very obscurely
known, much resembling mycelia with de-
tached conidia scattered on them.

BIBL. Berk. Br. .Ffor.ii.pt. 2. 346; Fries,
Sum. Veg. 492, 495, 521; Greville, Crypt.
Flor. pi. 108. figs, 1, 2.

SPUMAHIA, Pers.— A genus of Myxo-
mycetes, the peridia of which are divided
internally into chambers by ascending folds,
and in S. alba are either sessile and pass above
into torn white laminae, or are stipitate and
divided, and form corniculate peridiolea
bursting above ; the latter is probably the
perfect form. The whole plant looks at
first like white froth ; it grows on grasses
&c., generally at a little height from the
ground.

BIBL, Berk. Br. Fl. ii. pt. 2. 309 ; Gre-
ville, Crypt. Fl. pi. 267; Sowerby, Fungi

SPUMELLA.

[ 728 ]

STAINING.

(Reticularid), pi. 280; Fries. Sum. Vey.
449.

SPUMEL'LA, Cienk.— A genus of Fla-
gellate Infusoria. Minute, free or pedicled,
rounded or ovate, mouthless, with 1 long
and 2 short flagella. 8. cjuttula and 8. vim-
para = Monas g. and v . , Ehr. In pond water
and infusions. (Kent, Inf. 305.)

SPUTUM.— We omitted to notice under
EXPECTORATION the occurrence of fibrinous
casts of the smaller bronchi and pulmonary
air-cells in the expectoration of pneumonia.
They are best seen on mixing the sputa with
water, forming dichotomous cylinders with
rounded enlargements. They consist of fine
filaments, and are mostly covered with gra-
nule-cells, and are generally met with be-
tween the third and the seventh day.

Koch's. Bacillus tuberculosus of phthisis,
also deserves special attention.

BIBL. Remak, Diagn. fyc. Untersuch., Ed.
Mn. Jn. 1847, vii. 350; Gibbes, Lancet,
1882, ii. 183 & 797 ; Jn. M. Sac. 1882, ii.
572.

SPYRID'IA, Harv.— A genus of Cerami-

Spyridia filamentosa.
Fragment with a favella and ramules.
Magnified 25 diameters.

aceae (Florideous Algae), containing one
British species, S. filamentosa (fig. 693),
having a dull-red, cylindrical, filiform,
much -branched frond, consisting of a cham-
bered tube, the articulations of which are
short, and the walls of which are composed
of small angular cells. It arises from a
broadly expanded disk. The branches are
clothed with setaceous ramules. The
favella are stalked, gelatinous, and lobed,
surrounded by a few ramules and contain
two or three masses of spores. The tetra-
spores occur attached to the ramules. An-
theridia have not yet been observed.

BIBL. Harvey, Mar. Alg. 166, pi. 22 D.

SQUAMA'KIA, DC.— A genus of Placo-
dei (Lichenaceous Lichens) . Six species,
on calcareous rocks and earth. (Leighton,
Lich. Fl. 157.)

SQUAMEL'LA, Bory, Ehr.— A genus of
Rotatoria, of the family Euchlanidota.

Char. Eyes four, frontal; foot forked;
freshwater.

8. oblonga (PL 44. fig. 29). Carapace
depressed, elliptical, or ovate-oblong, hya-
line ; toes slender, long ; length 1-216".

S. bractea. Toes short and thick. (Ehr.
Inf. 479.)

'SQUAMULI'NA,Schultze.— An obscure,
small, parasitic, scale-like, opaque Forami-
nifer, probably Nubecularian.

BIBL. Schultze, Org. Polyth. 56; Car-
penter, For. 67.

STACHEI'A, Brady.— An adherent Are-
naceous Foraminifer, with numerous subdi-
vided chambers, acervuline or in irregular
lavers. Six fossil species (Carboniferous).
(Brady, Carbonif. Foram., Pal. Soc. 1876,
107.)

STAOHYLTO'IUM , Link.— A genus of
Mucedines (Hyphomycetous Fungi), nearly
related to Botrytis, distinguished apparently
only by the subpedicellate spores. Fries
states that these are developed within a
fugacious veil (?). BOTBYOSPOBIUM dif-
fusum, Corda, is included here by most
authors. S. bicolor and 8. terrestre, 'having
quaternate sporiferous branches at the upper
joints of the erect, simple filaments, grow
upon decaying herbaceous plants and rotten
sticks.

BIBL. Berk. Br. Fl. ii. pt. 2. 341 ; Fries,
Sum. Veg. 490; Greville, Crypt. Flor. pi.

STAINING. — The staining or dyeing
process was introduced by Geiiach, after
observing in his carmine injections, how
differently the elements of the tissues were
dyed by the colouring-matter.

The general action of the dye is, that the
nuclei and the protoplasm of the cells are
deeply coloured, while the cell-walls are
but little acted upon, and the intercellular
substance is hardly at all affected. The
cause of this difference in the dyeing effect
lies partly in the physical and partly in the
chemical condition of the organic matter.

If the dye-liquor be too strong, or its
action too long continued, the whole tissue
will become confusedly coloured, and its
elements undistinguishable.

The dyes which have been used are very

STAINING.

[ 729 ]

STAINING.

numerous ; we will give a sketch of the
principal and their uses.

Among these are carmine, indigo-carmine,
alkaline sulphindigotates, saffron, aniline
blue, cosine, fuchsine, magenta, logwood,
picric acid, ink, and Judson's dyes.

Frey recommends that 3 to 6 grains of
carmine (better cararinic acid ?) be dissolved
in a few drops of Liq. Ammon., with an
ounce of distilled water. To the filtered
liquid is added 1 ounce of glycerine, and
2 to 3 drachms of alcohol. This solution
may be used alone, diluted with water, or
with glycerine. The duration of the mace-
ration will vary according to the kind of
tissue and the strength of the dye-liquor ;
in some cases a few minutes are enough, in
others 24 hours are required. The pieces
of tissue are then washed with water or a
very weak acid (an ounce of distilled water
with 2 or 3 drops of acetic acid). Fresh
tissues, or those hardened by alcohol are
best; next those previously treated with
chromic acid or bichromate of potash.
Preparations to be .preserved in feebly acidi-
fied glycerine require to be less dyed than
those to be mounted in balsam.

Gerlach used a concentrated solution of
carmine in ammonia, and placed the sec-
tions of brain and spinal cord, previously
hardened by solution of chromic acid, in the
carmine solution for ten or fifteen minutes.
They were then well washed in water and
treated with acetic acid ; subsequently the
water and acid were removed by absolute
alcohol ; and the preparations were then
mounted in Canada balsam. Afterwards
he found that better results were obtained
by using dilute solution of carmine and
ammonia — for instance, two or three drops
of the ammoniacal solution to an ounce of
water. He advised also maceration in this
solution for two or three days. Beale's
carmine fluid for staining protoplasm is
made as follows : —

Carmine 10 grains.

Strong liquor ammonise | drachm.

Price's glycerine 2 ounces.

Distilled water 2 ounces.

Alcohol | ounce.

The carmine in small fragments is to be
placed in a test-tube and the ammonia
added to it. By agitation and heat the car-
mine is soon dissolved ; then the solution is
boiled for a few minutes and allowed to cool.
After an hour any excess of ammonia will
have escaped; the glycerine and water
may then be added and the whole filtered.

The clear fluid is to be kept in stoppered
bottles ; and should any carmine be preci-
pitated, a drop or two of liquor nmmomse
should be added. Care should be taken
that the solution and the tissue to be stained
have not too alkaline a reaction; other-
wise the staining will be too intense, and
some of the tissue surrounding the proto-
plasm will be destroyed. The permeating
power of the fluid is increased by the addi-
tion of alcohol and water. This is a most
valuable staining agent, but requires care.
Thiersch recommends: — carmine 1 part,
caustic ammonia sol. 1 part, distilled water
3 parts ; the solution is to be filtered ; oxalic
acid 1 part, distilled water 22 parts. One
part of the carmine solution is to be mixed
with 8 parts of the oxalic acid solution, and
12 parts of absolute alcohol are to be added.
Should the solution turn out orange-co-
loured, more ammonia should be added.

A solution of carmine in borax is some-
times used — 4 parts of borax dissolved in
56 parts of water, to which is added 1 part
of carmine. The filtered solution is mixed
with 2 volumes of alcohol. This solution
answers well in dyeing cartilage.

Frey gives the following formula for
Thiersch's blue staining fluid : — Oxalic acid
1 part, distilled water 22 parts, indigo-car-
mine as much as the solution will take up.
Another solution of oxalic acid and water
in the same proportion is required; and one
volume of the first solution is mixed with
two volumes of the last and nine of absolute
alcohol. An aniline-blue solution may be
made as follows: — Soluble aniline blue
A grain, distilled water 1 oz., alcohol 25drops.
This fluid is not acted on by acids or alkalies.
Magenta colours rapidly, and hence it is very
useful; but its effects are not permanent.
Rutherford gives the following formulae : —
Crystallized magenta 1 grain, absolute alco-
hol 100 minims, distilled water 5 oz. This
is used for the tissues generally; and the
following is for blood-corpuscles : — Crystal-
lized magenta 1 part, rectified spirit 50
parts, distilled water 150 parts, glycerine
200 parts.

Very often nerve does not stain readily
with carmine after hardening in a solution
of chromic acid. This may be obviated by
placing the section in absolute alcohol for a
short time in order to get rid of the water ;
then it is placed in a solution composed of
water 300 to 600 parts, and chloride of pal-
ladium 1 part. As soon as a pale straw-
colour is seen on the section, it may be

STAINING.

[ 730 ]

STAMENS.

removed from tlie solution and washed, and
then placed in a strong solution of carmine
and ammonia. A very few minutes will
suffice to stain the axis-cylinders red and
the medullary matter yellow (Qu. Mic. Jn.
1872, 160).

A blue staining agent, useful for treating
specimens of the spinal cord, is formed by
the reaction of molybdate of ammonia, iron
filings, and hydrochloric acid (Qu. Mic. Jn,
1872,161). *

A logwood staining solution, which con-
sists of an ounce of saturated solution of
logwood and alum mixed with two drachms
of 75 per cent, alcohol, is useful for the
nervous elements (Qu. Mic. Jn. 1873, 87,
& The Lens, July 1872).

Other staining agents comprise especially
the chlorides of gold, potassium and palla-
dium, oxide of uranium, nitrate of silver,
and osmic acid. In these, except perhaps
in the last, a secondary decomposition
occurs before the colour is imparted to the
tissues ; and the greatest possible care must
therefore be taken to allow for the granular
or striated condition which such precipitates
may assume, and for their collecting in
tubes and between tissues. An excellent
formula for staining ganglion-cells especially
is as follows: — Bichromate of ammonia
1 to 2 per cent, solution in water. Place
the fresh nerve-substance in it for 15 or 20
days. Then dip it, after having made sec-
tions, in water 10,000 parts, double chlo-
ride of gold and potassium 1 part ; wash in
hydrochloric acid 1 or 2 parts in 3000 water.
Then dip for ten minutes in the following
mixture: — Hydrochloric acid 1 part, and
1000 parts of a 60 per cent, solution of
alcohol ; immerse in absolute alcohol, clear
with oil of cloves, and put up in Canada or
Dammar balsam. Staining with chloride
of gold may be conducted as follows, the
object being to stain nerve^fibres : — Chlo-
ride of gold \ part, distilled water 100 parts.
Place pieces of fresh tissue in this for a few
minutes until they become tinged with
yellow, then in dilute acetic acid (1 to 2 per
cent.), or in concentrated tartaric acid solu-
tion for a few (10-15) minutes. Expose to
light until a violet colour appears. Mount
in glycerine. There is great uncertainty in
the results of this process ; but care 'and
experience overcome most of the difficulties
and produce magnificent preparations ;
nevertheless no results are worth recording
which are obtainable by this process alone,
and which are not the same as those visible

wifh glycerine and carmine staining solu-
tions. The discrepancies of observation of
different and equally dogmatic observers are
most instructive. In fact in some tissues
the gold solution will stain many histolo-
gical elements (see Klein, Qu. Mic. Jn.
1872, 21 ; and Moseley, Qu. Mic. Jn. 1871,
58).

Nitrate of silver for staining epithelial
cement in capillaries, lymphatics, &c. The
solution must be clear and weak, and of
1 part nitrate of silver to 200, 400, or 800
of distilled water. The fresh tissues must
be macerated in the solution for one to
three minutes, r. : :1 then in a solution of
dilute acetic acid (1 to 2 per cent.) for a
minute or two. Then place in glycerine
and expose to the light ; or after removal
from the nitrate-of-silver solution the tissue
should be washed in distilled water, or in
a weak solution of common salt before ex-
posure to light.

In examining the tendinous centre of the
diaphragm of any of the smaller mammalia,
the part should be placed in the nitrate-of-
silver solution and brushed over with a
camel's hair pencil and then removed and
treated as above.

Solution of osmic acid may be used as a
hardening agent, also as a staining medium.
Solution of 1 per cent., and usually of much
less, blackens many tissues freely, especially
the white substance of Schwann in nerves,
and fat. It is very useful in investigating
the minute anatomy of the Invertebrata.

Many parts of animal tissues may be
stained by maceration in a weak solution of
acetate of lead, washing in water, and
digesting with weak hydrosulphuret of am-
monia. As usual, the nuclei are rendered
very black and distinct, the whole tissue
being rendered brown.

Vegetable tissues may be stained in the
same way as the animal structures. The
aniline dyes answer best (Beatty, Mn. Mic.
Jn. xiv. 57).

BIBL. Beale, How $c. ; Strieker's Hist.,
Intro. ; Frey, Mikros. ; Rutherford, Hist. ;
Jackson, Qu. Mic. Jn. 1874, 139; Ehrlich,
Schultze's Archiv, 1873, xiii. 263; Gibbs,
Hist.-, Tafani, Jn. M. £oc. 1878, i. 82;
Merbel, Mn. Mic. Jn. xviii. 242 ; Sternberg,
Jn. M. Sc. 1882, ii. 571 (staining Bacteria] ;
Schwartz, Sitz. Ber. Wien. Ak. 1867, Iv.
671.

STAMENS.— The fertilizing organs pro-
ducing the POLLEN, surrounding the pistil
in perfect Flowering plants, or occurring

STARCH.

[ 731 ]

STARCH.

alone in the barren flowers of the monoe-
cious and dioecious genera. Stamens pre-
sent a great variety of interesting points for
examination under a simple microscope
with a low power, in their forms, append-
ages, pores, &c. For the compound micro-
scope they afford good material for the study
of development of cells in the pollen, the
POLLEX-grains themselves, and the spiral-
fibrous tissue of their ANTHERS.

STARCH or AMYLUM.— This substance,
with the exception of the protoplasm, is the
most generally diffused of all the products
met with in the interior of vegetable cells,
and occurs in the form of transparent gra-
nules, of varied size and form and in varying
quantity, in ;;11 classes of plants but the
Fungi. * It has been stated that it sometimes
exists in a diffused or formless condition ;
but this seems questionable. All starch -
grains appear when newly formed as mi-
nute spherical bodies, and very many never
advance beyond this stage ; but a consider-
able proportion of the grains, in all cases
where the starch becomes an important and
considerable element in the cell-contents,
increase in size, and acquire a more or less
definite form, diverging from the spherical,
and often characteristic of the particular
plant in which the grain is produced. The
grains in a single cell mostly vary very
much in size, on account of their different
degrees of development ; but the full-grown
characteristic grains of the same species of
plant agree tolerably well in size. One of
the most remarkable peculiarities of starch
is the fact that it assumes a blue colour
when iodine is applied to it, which in most
cases affords a ready means of detecting its
presence. The smallest grains are almost
too minute to measure, and even their de-
termination by the application of iodine is
sometimes unsatisfactory; the largest grains,
such as those of Canna and the potato, for
example, attain a length of more than
1-400".

The starch-granule is a definitely organ-
ized structure, although its existence in
relation to that of the cell is transitory. It
consists of assimilated food, deposited in a
definite form insoluble in the ordinary cell-
sap, through a process of organization ana-
logous to that by which the development of
the cell itself is effected. It is related
closely to the cellulose structures of the cell-
wall through the remarkable secondary
layers found in the ALBUMEN of certain
seeds, composed of the substance called

amyloid, which sometimes takes a blue
colour when iodine is applied to it, and,
like starch, is ultimately dissolved and re-
moved to furnish material for development.
The structure of the starch-granule has
formed the subject of much debate, which,
however, seems to have originated rather
through considerations relating to the deve-

but when the granules acquire appreciable
dimensions, concentric lines may be ob-
served, more or less distinctly in different
cases, which lines increase in number with
the increase of size, in many cases, however,
soon becoming excentrical from the pre-
ponderating growth of one side of the
granule. In freshly extracted granules the
original centre usually appears solid or with
a minute black point ; but if the starch is
dry, the centre appears hollow, sometimes
is even occupied by air; and some starch-
grains, as in 3ris pallida,jlorentina, &c., have
a large cavity. If strong alcohol is applied
to fresh grains, the abstraction of water
likewise produces a hollow in the central
point of growth ; and in all these cases,
cracks not unfrequently run out towards
the surface. The point in question, the
startkg-point of growth, solid or hollow as
the case may be, is sometimes called the
hilwn or the nucleus : the former term arose
out of the mistaken hypothesis of its being
a point of attachment to the cell-wall ; the
latter term is admissible in a general sense
as merely indicative of its precedence in age
of the general mass of the grain. It is
sometimes asserted that this point or nucleus
is a pore or funnel-shaped cavity ; but this
is altogether a mistake, as may be readily
proved by gently roasting a few starch-
granules of the potato on a slide, and ob-
serving how the expanding air blows up
the dextrine, into which the starch is
changed, in the form of a bubble or bladder.
Sometimes small granules occur in the
potato with a large cavity and thin walls.

The lines seen in the starch -granules are
the boundaries of superimposed layers of its
substance ; sometimes these are 'very di-
stinct, sometimes very faint. Often more
distinct lines appear at intervals in the
series of the same granule (PI. 46. fig. 31)«;
and in these cases even a thin vacancy, or
in the dried granules a stratum of air, seems
to exist between the layers. The markings
have been described as " folds " on the

STARCH.

[ 732 ]

STABCH.

starch-granules; "but their dependence on
the existence of the concentric layers is
beyond doubt. They are seen in the proper
relative positions when the granules are
rolled over in all directions beneath the
microscope j their relative numbers and
forms correspond to the size and stage of
development of the granules in the same
plant ; and other characters connected with
the physical structure confirm the conclu-
sions from simple inspection.

Starch is not chemically an individual
substance, but consists of two independent
isomeric substances : one of which, granu-
lose, is soluble in saliva, is coloured blue by
iodine, and is dissolved by weak solutions of
chromic acid ; while the other, cellulose,
which composes from 2 to 4 p. c. only of the
grains, is not affected by saliva or iodine, and
is soluble in solution of cuprate of ammonia,
but not in chromic acid solution.

Starch is usually stated to be unaffected
by cold water, and this is generally the case ;
but if the granules of Tous-les-mois are
crushed before placing them in water, so as
to expose the internal substance, the water
is sometimes absorbed by the inner layers,
and these, swell up considerably without the
outer layers being affected. When dry
starch-granules are heated gradually upon a
slide, until some of them assume a yellowish
colour, either the air-bubble above-men-
tioned appears— occasionally with a partial
separation of the concentric layers through
expansion of the films of air existing between
them, while other parts become fused, — or
the general shape remains unchanged, and
the striae gradually vanish, becoming melted
into a mass, as it were, the starch itself
being converted into dextrine. When
starch-granules are heated in water to the
boiling-point, they usually soften and
"blow up " into a large sac, the inner part
softening first, and pushing out the more
superficial ; if the sac bursts, the inner sub-
stance sometimes partly escapes in the form
of cloudy flocks, but is not dissolved. Di-
luted sulphuric acid acts somewhat in the
same manner as hot water ; but if stronger
acid is allowed to attack the granules locally
or partially by flowing in from one side
upon the object, very remarkable appear-
ances present themselves : the acid touching
' certain parts of the granule first, or acting
most quickly on softer portions, causes the
softening internal layers to expand and
bulge out the external layers at particular
points (like hernice) until the entire grain is

softened, when these coalesce and the whole
expands into a thin sac. Gradual action of
the acid causes a more uniform expansion,
which is usually accompanied by a sudden
crack running out from the nucleus into the
substance (indicating the abstraction of
water ?), followed almost immediately by a
collapse of the wall above this crack, and
a sudden expansion of the whole into a sac
or an irregular gelatinous film. /Solution of
potash produces much the same effect as
dilute sulphuric acid.

All the above appearances indicate that
the starch-granule is composed of concentric
" shells " of a substance of the same nature,
but less dense and more rich in water in the
interior layers, firmer, less hydrated, and
more resisting in proportion to the distance
from the starting-point of growth or nu-
cleus ; and, according to modern views, the
layers are alternately more and less hydrated.
With polarized light, moreover, the starch-
granule exhibits a black cross, and with a
plate of selenite a beautiful coloured system,
especially well seen in large grains like those
of the potato or Tous-les-mois.

Pure starch is coloured blue by iodine,
whether in its natural state or softened by
hot water, the depth of the colour depend-
ing on the quantity of iodine ; where much
is added, the colour is almost black. When
dilute sulphuric acid has been added pre-
viously, the colour is rather purple than
blue, especially the faint tinge given at first
by weak solution of iodine. When the
starch grains are heated dry, the colour
given by iodine changes, proportionately to
the violence of the action, from blue to
purple, red-wine colour, and finally brown ;
the starch being converted into dextrine.
The best application is the solution of iodine
in iodide of potassium ; and this should be
used very weak in investigation of starch.

Starch-granules occur either isolated (PI.
46. figs. 8 & 21), or in groups (figs. 7, 10, 11)
(in the latter case mostly with flat faces, so
as to fit together into round, oval, or similar
forms), or packed closely in the parent cell
in such numbers that they press upon each
other and appear like parenchymatous cells
(PI. 46. figs. 3 & 12). In the actively vege-
tating parts of plants, starch-granules occur
very generally imbedded in the green glo-
bules called CHLOBOPHYi.L-granules, either
singly or in groups ; this is seen especially
well in the cells of the Confervaceaa, of the
Hepaticae, the prothallia of Ferns, in the
leaves of aquatic plants, such as Vallisneria,

STARCH,

[ 733 ]

STARCH.

in autumn, &c. The free granules occur
more particularly in the colourless organs
of plants — in tubers, rhizomes, roots, and the
cambium region in the season of rest, in
the endosperm of ovules, or the ALBUMEN or
cotyledons of seeds, &c. The parenchyma-
tously grouped granules are found in the
albumen of seeds, especially of inaize and
rice. The comparison of the states and of
the course of development of the crowded
granules of maize throws much light upon
the manner in which starch-granules are
formed.

In the first place, two rival doctrines exist
as to the order of development of the parts
of the granule. Most authors assert that
the granules grow by the superposition of
layers from within outwards, consequently
that the outermost layers are the youngest.
Other authors, especially Nageli, comparing
the granule to a cell, assert that the layers
are formed internally, the older ones ex-
panding to make room for them. There
can be no doubt that the first view is cor-
rect. In the next place a variety of notions
have been put forth as to the origin of the
starch-granule and its relation to the rest
of the contents of the cell, especially the
chlorophyll. It is curious to note the error
into which earlier observers fell from the
want of the guiding thread furnished by a
knowledge of the function of the proto-
plastic structures connected with the pri-
mordial utricle. The idea that the starch-
granule sprouted out from the cell-wall
corresponded with the original view of the
origin of the septum in cell-division ; while
the hypothesis that starch is developed from
chlorophyll, and the contrary notion that
starch-granules form the nuclei of chloro-
phyll-granules, both rest on actual pheno-
mena, in which, however, the chlorophyll
proper, that is the mere green colouring-
matter, bears no important share.

The development of the starch-granule is
very beautifully illustrated in the gradual
ripening of the seeds of Maize j and in im-
perfect seeds, different parts of the same
grain often exhibit various stages of growth.
The tigs. 1 and 3 of PI. 4(3, show the gradual
formation of the starch-granules by depo-
sition from the internal surface of vacuoles
in the protoplasm filling the cell, exactly in
the same way as the primordial utricle
secretes cellulose layers upon its outer sur-
face. Fig. 28 shows minute starch-granules
originating in the same way in the proto-
plasm-current connected with the nucleus

in the white lily ; and Criiger, who first
published this view in a decided form, has
shown that the large granules, with an ex-
centric hilum, originate in a similar position,
and owe the excentricity of their form to
the fact of their remaining imbedded at the
thicker end in the protoplasmic threads of
the primordial utricle, while the small free
end is gradually pushed out further from
the nutrient mass. The existence of starch-
granules in chlorophyll-masses is thus clearly
enough accounted for, now that we know
the chlorophyll-globules to consist of masses
of protoplasm coloured green by^ the presence
of an extremely small quantity of a sub-
stance acquiring a green colour under the
influence of light. Starch originates in
vacuoles in this as in any other protoplasm.
The groups of granules are formed through
the simultaneous origin of a number, in
vacuoles excavated in one large globule of
chlorophyll or colourless protoplasm. We
have tracedthis in the fronds of the Hepaticse.
It remains to speak of the diversities of
form and size of the large and perfect gra-
nules in different plants. A glance at
Plate 46 will give some idea of these, and
an inspection of the individual figures will
show how remarkably the characteristic
forms may vary in ne'arly related nlants,
even genera of the same family, as is the
case with the ordinary Cereal grains. Thus
in Maize (figs. 1,3,5), where the small grains
are, as usual, originally roundish or oval
(fig. 5*), they gradually press upon one an-
other and become polygonal — in the cells of
the centre of the grain, where they are less
densely packed, remaining with obtuse edges
and angles (fig. 6), in the cells of the horny
outer part of the grain, where they adhere
more or less firmly together, forming an-
gular parenchymatous masses (fig. 3). The
central cavity is large here. In the grain
of Wheat we find delicate, transparent, len-
ticular granules (fig. 8), the striae faint ; in
Barley (fig. 9) they are more irregularly
discoid, with a thickened edge, the striae
obscure j while in the Oat (fig. 10) the
granules are of very small size, but of angular
forms and packed together in large numbers,
so as to form roundish masses with a smooth
surface, which readily break down into their
components when pressed ; the separate seg-
ments all exhibit their separate black crosses
in polarized light. In Rice (fig. 12) we find
somewhat similar conditions to those in
Maize ; but the granules are much smaller
and more firmly united, whence the gritty

STAURASTRUM.

C 734 ]

STAUROCARPUS.

character of rice-flour. In the Leguminosae,
and the pea (fig. 6 b*, p. 28), the granules
are oblong, the striae distinct, and the hilum
radiate. In the Potato the starch-granules
(fig. 21) are larger than any of the above j
they are numerous and closely packed in the
cells (fig. 20) . Among the more remarkable
forms of starch are the large grains of the
Cannes (fig.25),Jfw$«(fig.24),andinost of the
Zingiberaceae (fig. 19). Some East-Indian
Arrow-root (fig. 18) has compound grains
of large size (mostly detached in the pre-
pared farina). True West-Indian Arrow-
root, from Maranta arundinacea, is repre-
sented in fig. 26. Various other kinds are
illustrated in PI. 46. DiefferibacMa Seguina
(Araceae) has remarkable lobed granules.

Here may be mentioned the so-called tannin
starch-grains. These resemble ordinary
starch-grains, but the cellulose is replaced
by tannin, the .granulose being unaltered ;
they are coloured blue-black by iron solution,
and are found in wood, seeds, &c.

Starch-granules are usually isolated by
slicing the tissues in which they exist, and
washing them out. When they are to be
observed in situ, either delicate transparent
structures (as in the Cryptogamia) must be
selected, or sections very carefully made.
The cells filled with starch of the potato
(PL 46. fig. 20), &c., may be isolated by ma-
cerating the structures in water for a day or
two. Starch-granules may be preserved for
a certain time in glycerine ; but they are,
perhaps, best taken fresh from a store of
dry granules, when required for examination.

BIBL. Martin, Phil. Mag. iii. 277 ; Busk,
Mic. Tr. i. 58 ; Allinan, Mic. Jn. ii. 163 ;
Criiger, Bot. Zeit. xii. 41, Mic. Jn. ii. 173 ;
E. Quekett, Ann. N. H. xvii. 193 ; Caspary,
Jahrb. wiss. Botanik, i. 448 ; Trecul, Ann.
Sc. Nat. 4. x. ; Nageli, Starkekorner fyc. ; and
Sitzungsber. bayer. Ak. 1865 ; Sachs, Bot.
58 ; Henfrey-Masters, Bot.

STAURAS'TRUM, Meyen.— A genus of
Desmidiaceae.

Char. Cells single, constricted at the
middle ; end view angular or circular, with
a lobato -radiate margin, or rarely com-
pressed with a process at each end. Spo-
rangia generally spinous and often globose.

Many British species.

S. dejectum (PI. 14. fig. 26). Segments
smooth, lunate or elliptical, constricted por-
tion very short; end view with inflated
awned lobes. Common ; length 1-830".

8. maraaritaceum (PI. 14. figs. 28, 29).
Segments rough, tapering at the constric-

tion, and with short lateral processes ; end
view with five or more short, narrow, ob-
tuse rays. Length 1-1176".

S. gracile (PI. 14. fig. 30). Segments
rough, elongated on each side into a slender
process terminated by minute spines ; end
view biradiate. Length 1-770 to 1-540".

BIBL. Ralfs, Desmid. 119 ; Rabenht. Alg.
iii. 199 ; Archer and Dixon, Qu. Mic. Jn.
viii. 77 ; ib. xvii. 103.

STAURIDIUM, Duj.— A genus of
Hydroid Zoophytes.

Char. Stems simple or branched, rooted
by a creeping filiform stolon ; polypes
borne at the summit of the stems with
several whorls of capitate tentacula in the
form of a cross.

S. productum. On marine algae. (Hincks,
Hyd. Zooph. 67.)

STAUROCAR'PUS, Hassall (Stauro-
spermum, Kiitz.). — A genus of Zygnemaceae
(Confervoid Algae), growing in boggy
freshwater pools ; distinguished by the re-
markable quadrate spore formed in the
cross branch produced by conjugation.
Hassall enumerates six species. He speaks
of, but does not describe or figure, the spores
of S. ccerulescens as filled with zoospores.
Thwaites, however, saw the spores of S.
gracilis resolved into four portions ; and pos-
sibly these may become converted into
zoospores like the spores of BULBOCHJETE ;
or probably they ger-
minate directly, as in
Spirogyra.

S. gracillimus. Fila-
ments 1-4200" to
1-3960" in diam. j
spores acutely qua-
drangular.

S.gracilis (fig. 694,
and 'PI. 9. fig. 16).
Filaments thicker
than in the last;
spores cruciform.

S. glutinOSUS. Fila- Conjugating filaments with
ments 1-1800" to spores (zygospores).
1-1560" in diam. ; blu- MaSnified ">0 diameters.

ish green, lubricous; spores four-sided, with
the 'angles rounded.

S. ccerulescens. Filaments about the same
size as the last j spores cruciate, with obtuse
lobes.

S. quadratus. Filaments 1-2400" in diam. ;
spores between square and globose.

8. virescens. Filaments 1-3240 to 1-3000"
in diam. ; spores cruciate, emarginate.

BIBL. Hassall, Alg. 176; Kiitzing, Sp.

Fig. 694.

Staurocarpus gracilis.

STAUROGENIA.

[ 735 ]

Alg. 437; Tab. Phyc. v. pis. 8 & 9;
Thwaitee, Ann. N. H. xvii. 262; Ralfs,
Desmid. p. 146 ; Braun, Verjiingung, Ray
Soc. 1853, 287.

STAUUOGE'NIA, Kiitz.— A genus of
Unicellular Algae.

Char. Cubical, the cells arranged in
groups of 4, 8, and 16. Propagation by tran-
quil gonidia arising from repeated division
of the cell-substance. S. quadratum (PL 62.
tig. 21). In freshwater pools.

BIBL. Rabenh. Alg. iii. 80.

STAUROXETS, Ehr.— A genus of Dia-
tomaceoe ; including Staurostigma and Stau-
roptera.

Char. Frustules resembling those of Na-
vicula, but the median nodule expanded
into a transverse baud 01- stauros.

Striae resembling those of Navidda, or
intermediate between those of Navicula and
Pi/tnularia; often in \isible by ordinary
illumination.

The species or forms are numerous.

S. phcenicenteron (PI. 15. fig. 43. Valves
lanceolate, gradually attenuated towards
the somewhat obtuse ends ; stauros reaching
the margins of the valves; strise faint.
Freshwater; common; length 1-170"

S.pulcMla (PL 15. figs. 44,45). Valves |
oblong, ends obtuse; frustules in front
view broadly linear, constricted in the
middle, and rouuded-truncate at the ends ;
striae distinct ; stauros not reaching the
margins. Marine; length 1-70".

BIBL. Ehreub. Ber. Berl. Ak. 1843;
Kiitz. Bacill 104, and Spec. Ala. 89: Ra-
benh. Alg. i. 244.

STAUROSPER'MUM,Kutz.=SxAURO-
CARPUS, Hassall.

STEARIC ACID.— The crystals of this
fatty acid are represented in PL 11. fig. 16.

STEGANOPOREL'LA,Sniitt.— A gen us
of Polyzoa = Metnbranipora pt. (Hincks,
Polyzoa, 176.)

STEMONI'TIS, Gled — A genus of
Myxomycetes, consisting of little, somewhat
stamen-shaped plants, either separate or
fascicidated, growing on rotten wood, &c.
They appear at first in the form of a muci-
laginous tiocculent expansion (fig. 695), from
which the membranaceous peridia grow up
(fig. 696). Many of these remain abortive ;
others are raised upon stalks, ripen, and, on
the separation of the fugacious peridium,
display themselves somewhat in the form
of DIACH.E A,but with a bristle-like columella
and no remains of the peridium. The flat,
cylindrical or globose, reticulated capilli-

STENOGRAMME.

Fig. 695.

Stemonitis ferruginea.
Mycelium overgrowing decaying pine-leaves.

Fig. 696.

Stemonitis ferruginea.

Immature (fasciculate) peridia arising from the
mycelium.

tium is penetrated partly or through its
whole length by a columella continuous
with the peduncle ; the spores are inter-
spersed in the reticulations of the capillitium.
Capillitium and spores mostly of blackish
colour. There are numerous British species ;
& fusca is common. See ENERTHENEMA
and DIACHJEA.

BIBL. Berk. Br. Fl. ii. pt. 2. 317 ; Ann.
N. H. i. 257, vi. 431, 2. v. 366; Greville,
Crypt. Flor. pi. 170; Fries, Sum. Veg. 455 ;
Syst. Myc. iii. 156.

STENHE'LIA, Boeck.— A genus of Co-
pepodous Entomostraca. Two species, on
Laminaria and in dredgings. (Brady, Copep.
ii. 32.)

STENOC'YBE, Nyl.— A genus of para-
sitic Micro-lichens found on the thallus of
Thelotrema and Graphis — Sphinctrina,
Leighton. (Lindsay, Q. Mic. Jn. 1869. 146.)

STENOGRAM'ME, Harv.— A genus of
Rhodymeniaceae (Florideous Algae), con-
taining one very rare British plant, S. in-
terrupta, characterized by stalked, flat, fan-
shaped fronds, more or less divided dicho-
tomously into riband-like lobes, 3-5" high,
of a clear pinky-red colour. It is com-
posed of a central layer of large globular
cells, with a kind of rind of small cells.
The conceptacles form a sort of sorus or dark

STENTOR.

[ 736 ]

STEPHANOSPH^ERA.

line resembling a rib, up the centre of each
fertile lobe. Tetraspores and antheridia
unknown.

BIBL. Harvey, Marine Alg. 123, pi. 15 D.

STENTOR, Oken.— A genus of Hetero-
trichous Infusoria, of the family Bursarina.

Char, Body conical or trumpet-shaped,
free, or sessile and attached by the narrow
base, covered with cilia; anterior portion
widened and fringed with a marginal row
of longer cilia, with a spiral row of cilia
extending from it to the mouth. Fresh-
water.

These Infusoria are among the largest
and the most beautiful of the class. The
body is very contractile and liable to varia-
tion in form, often becoming ovate, oblong,
or globular; the nucleus is moniliform or
strap-shaped. Reproduction by oblique fis-
sion, and by germs arising from the nucleus.
The encysting process has been noticed in
some of the species.

According to Lachmann, in S. Mullen,
polymorphus, and Itceselii, near the plane of
the ciliary disk is a large contractile vesicle,
from which a longitudinal vessel with
several dilatations runs to the posterior ex-
tremity of the body"; also an annular vessel
round the ciliary disk, close under its row
of cilia.

S. Mutteri (PI. 32. fig. 3). Body colour-
less unless from containing foreign coloured
particles, with a fringe of cilia or a ciliated
crest extending from the mouth to near the
middle of the body; nucleus moniliform.
Length 1-24"

Several other species.

Dujardin places this genus in the family
Urceolarina.

BIBL. Ehr. Inf. 261 ; Stein, Infus., pas-
sim; Pritchard, Inf. 581; Clap.'et Lach.
Inf. 222; Kent, Inf. 588; Lankester, Qu.
M. J. 1873 (col. matter}.

STEPHANOC'EROS, Ehr.— A genus of
Rotatoria, of the family Flosculariaea.

Char. Eyes single ; rotatory organ divided
into five tentacle-like lobes, furnished with
whorls of vibratile cilia; body attached
by the base to a cylindrical hyaline ca-
rapace.

8. Eichhornii (PL 44. fig. 25). The only
species. Freshwater ; length 1-36". This
beautiful animal uses the lobes of the ro-
tating organ to catch its prey, in the manner
of Hydra. At a (fig. 25) are seen the tre-
mulous bodies, above which is a row of
roundish globules, called by Ehrenberg ner-
vous ganglia.

BIBL. Ehr. Inf. 400; Pritchard, Inf.
668 ; Cubitt, Mn. Mic. Jn. iii. 240.

STEPHANODIS'CUS, Ehr.— A genus
of Diatomaceae.

Char. Frustules discoidal, single ; valves
circular, alike, not areolar (under ordinary
illumination), and with a fringe of minute
marginal teeth ; freshwater.

S. berolinensis has the valves finely ra-
diate, with mostly thirty-two teeth, and is
1-1150" in diameter. S. Niagara (PI. 18.
fig. 26) ; 8. lineatm (fig. 27) ; S. sinensis
(tig. 28) ; S. JEgyptiacus (fig. 29) ; S. Bra-
maputrce (fig. 29*).

BIBL. Ehrenb. Ber. Berl Ak. 1845, Ixxii. ;
Kiitz, Sp. Alg. 21 ; Rabenht. Alg. i. 36.

STEPHANOGO'NIA, Ehr.— An obscure
genus of fossil Diatomaceae.

Char. Frustules resembling those of Mas-
togonia, but with the apices of the valves
truncate, angular, and spinous.

Two species found in Bermuda and North
America. S. polygona (PI. 18. fig. 30).

BIBL. Ehrenb. Ber. Berl. Ak. 1844, 264;
Kiitz. Sp. Alg. 26; Pritch. Inf. 814.

STEPHANO'M A = PANDOBINA.

STEPHANOM'ONAS, K.— A genus of
Cilio-Flagellate Infusoria. Free, ovate,
with an anterior circle of cilia, and a single
flagellum. S. locellus; freshwater. (Kent,
Inf. 466.)

STEPH'ANOPS, Ehr.— A genus of Ro-
tatoria, of the family Euchlanidota.

CJiar. Eyes two, frontal, foot forked;
carapace depressed or prismatic; anterior
part of body expanded so as to form a fron-
tal hood ; jaws each with a single tooth.

8. cirratus (PL 44. fig. 28). Carapace
with two posterior spines j freshwater ;
length 1-240".

of. muticus has the carapace without spines
posteriorly, and the eyes have not been
recognized ; whilst S. lamellatus has three
posterior spines.

BIBL. Ehr. Inf. 478 ; Pritch. Inf. 699.

STEPHANOPYX'IS, Ehr.— A genus of
Diatomaceae = Pyxidicula in part.

STEPHANOSI'RA, Ehr.— A genus of
Diatomaceae.

Char. Frustules united into a short fila-
ment, disk with radiating series of minute
pun eta and a marginal crown of teeth.
Allied to Stephanodiscus and Melosira. On
trees. (Pritchard, Infus. 823.)

STEPHANOSPELE'RA, Cohn.— A ge-
nus of Volvocineae (Confervoid Algae).
S. pluvialis (PL 48. fig. 22) is nearly related
to Pandonnat consisting of a large hyaline

STEREOCAULON.

[ 737 ]

STICTEI.

globe with eight biciliated green cells,
placed at equal distances on the equator.

BLBL. Cohii, Sieb. $ Kollik. Zeitechr. iv.
77, Ann. N. H. x. 321, pi. 6; Mic. Jn. vi.
131; Rabenh. Alg. iii. 100; Archer, Qu.
Mic. Jn. 1865, 116.

STEREOCAU'LON, Schreb.— A genus
of Cladodei (Lichenaceous Lichens). S.
fMtschale, the most distinct species, is abun-
dant on rocks and stones in mountainous
districts. Thallus greyish and rough, apo-
thecia conglomerated, blackish brown j sper-
mogonia in little brown heads, near the
apothecia. Other species.

BIBL. Hook. Br. Fl. ii. pt. 1. 237 ; Tu-
. Ann. Sc. Nat. 3. xvii. 197 ; Engl. Bot.
pi. :>2 ; Leighton, Lich. Fl. 69.

STEREOXE'MA, Kutz. — A supposed
Alga of the family PhaBoneineae (Kiitzing),
stated by Cohn, however, to consist of the
decaying stalks of ANTHOPHYSA. (Kutz.
Sp. Alg. 160.)

STE'REUM, Fr.— A genus of Auricula-
rini (Hymenomycetous Fungi), character-
ized by its coriaceous substance, and even
hymenium without bristles, as in Hymeno-
chccte.

The species are numerous, amongst which
Stereitm hirsutum is one of our commonest
Fungi.

BLBL. Fr. Ep. 548: Berk. Outl t. 17.
f. 7; Cooke, Handb. 316.

STERIG'MATA.— The term applied by
Tulasne to the filaments forming the pedi-
cels of the sperinatia in the FUN<H (PL 26.
figs. 2, 3).

STERROM'ONAS, Kent.— A genus of
Flagellate Infusoria. Free, elongate, with
t\vo flagella, the longer rigid, the shorter
flexible and vibratile. S. formicina, in
vegetable infusions, salt and freshwater.
(Kent, Inf. 420.)

STICHIDTA.'— Pod-shaped processes of
the fronds of Florideous Algae, containing
the tetraspores imbedded in them (fig. 157,
p. 236).

STICHOCH/E'TA, Cl. and Lachm.— A
genus of Hypotrichous Infusoria, fam. Oxy-
trichina. Free, elongate, narrowed and
with cirri in front, and with styles and
seta) behind. S. pediculiformis ; marine.
(Kent, Inf. 775; 01. & Lachm. Inf.
152.)

STICHOCOC'CUS, Nag.— A genus of
Palmellaceae, consisting of very minute, ob-
long, thin- walled, green cells, single, or usu-
ally arranged in rows. S. bacillaris (PI. 3.
fif. 25), on dump decaying wood, especially

of willows, walls, &c. (Rabenhorst, Fl. Alg.
iii. 47.)

STICHOSTE'GIA, D'Orb. (RHABDOI-
DEA, Schultze). — D'Orbigny arranged all
Foraminifera having uniserial or linear
growth under this head as an Order ; but,
besides the many straight Nodosarince,
there are several rectilinear forms of other
genera belonging to different Natural
Orders, as Lituola, Pavonia, Articulina, &c.

STICHOT'RICHA, Perty. — A genus
of Hypotrichous Infusoria. Elongate, va-
riable, narrowed in front; outer anterior
cilia very long, in a lateral row ; often con-
tained in a cylindrical carapace.

Several species; salt and freshwater.
(Kent, Inf. 775 ; Perty, Lebensf. 153.)

STIC 'T A, Ach.— A genus of Phyllodei
(Lichenaceous Lichens), with a tough fo-
liaceous thallus, growing over rocks and
trunks of trees, mostly in mountainous dis-
tricts. S. pulmonaria forms large shaggy
fronds of olive-green colour when fresh,
pale-brown when dry, pitted and reticu-
lated; apothecia mostly marginal, red-
brown. Sperinogonia occur scattered on
the upper surface, mostly near the ends of
the lobes.

BIBL. Hook. Br. Fl. ii. pt. 1. 208; Tu-
lasne, Ann. Sc. Nat. 3. xvii. 169, pi. 1;
Engl. Bot. pi. 572; Leighton, Lich. Flor.
11].

STIC'TEI, Fries.— A group of Helyel-
lacei (Ascomycetous Fungi), containing

Fig. 697.

Fig. 699.

Fig. 698.

Stictis versicolor.
Fig. 697. An open disk, emerged on the surface of

wood, having an irregular border.
Pig. 698. Vertical section of the same.
Magnified 20 diameters.

Fig. 699. Asci and paraphyses from the last. Magni-
fied 200 diameters.

several genera of plants, growing on wood,

3s

STICTINA.

[ 738 ]

STILBACEL

branches of trees, &c., bursting through
from beneath the bark when mature. Stictis
(CryptomyceSjBerk.; Propolis, Fr., S. Veg.}
versicolor (figs. 697-699) is common on
wood ; the upper surface of the open fruit
is white, and at length mealy.

BIBL. Berk. Br. Fl. ii. pt. 2. 214 ; Ann,
N. H. vi. 359; Fries, Sum. Veg. 372.

STIO'TINA, Nyl.— A genus of Phyllodei
(Lichenaceous Lichens). .Thallus variously
lobed or laciniato-lobate ; rliizinae simple;
granula gonima of a dark blue-green colour.
(Leighton, Lick. FL 108.)

STICTODIS'CUS, Grev.— A genus of
Diatomaceae. S. Hardmanianus, in the
Monterey deposit. (Grev. Mic. Tr. 1865,
98.)

STIGEOCLO'NIUM, Kiitz.— A genus of
Confervoid Algee, doubtfully referred to
Confervacese, growing mostly in brooks,
and composed of delicate branched fila-
ments, drawn out into delicate hyaline
points; attached to stones and forming
masses of a mucous or lubricous character.
The jointed filaments are composed of short
cells, possessing bright green contents ; the
entire contents of a cell are converted into
a single spore (with four cilia) and dis-
charged (PL 9. fig. 5) ; and the cell-wall is
so delicate that it generally vanishes at the
same time. Many species are described by
Kiitzing, formerly regarded as members of
the genus DRAPARNALDIA, which differs in
the number of spores produced in each cell,
and in possessing large primary filaments
with lateral tufts of delicate ones, re-
sembling those of Stigeoclonium (fig. 179,
p. 271).

8. protensum (PI. 9. fig. 6). Tufts of
filaments 1-36 to 1-60" hi^h, very much
branched and elongated ; primary filaments
1-1800" in diameter, joints equal or three
times as long (Drap. condensata, Hassall).

S. tenue. Tufts about 1-36" to 1-72"
high; filaments 1-2160" in diam., torulose;
set above with tufts of abbreviated branch-
lets (Drap. tenuisf Hass.)

S. clongatum. Filaments very slender,
1-2880" in diam.; branches erecto-patent,
often opposite, subramulose, flagelliform ;
joints three or five times as long as broad
(Drap. elong. Hass.).

S. nanum. Filaments highly mucous,
very slender, sparingly branched, branches
acuminate, not usually ciliate ; cells rather
broader than long (Drap. nana, Hass.).

BIBL. Kiitz. Sp. Alg. 352; Tab. Phyc.
iii. pis. 1-11 j Hassall, Br. Alg. p. 118;

Thuret, Ann. Sc. Nat. 3. xiv. 223, pi. 18 ;
Rabenh. Alg. iii. 375.

STIG'MA.— The part of the pistil of An-
giospermous Flowering Plants, upon which
the pollen rests to produce its pollen-tubes,
and where the orifices exist leading to the
cavity of the ovary. It is situated either
at or near the summit of the style or its
branches ; or, when this is absent, it is ses-
sile on the ovary. The surface of the stigma
is clothed with papilliforni or short tubular
cells, from which a tenacious secretion
exudes at the period when the ovules are
prepared to receive the pollen-tubes. At-
tached by this adhesive fluid and often
grasped by the papillae the pollen-grains
produce their tubes, which make their way
between the papillae to descend through
the conducting tissue of the style to the
placenta (PI. 40. fig. 30). These papilli-
form cells in a young state often form
favourable subjects for the stud}r of the pro-
toplastic cell-contents, and also of the fluid
colouring-matter. The forms of the stigma
are exceedingly varied and sometimes very
elegant; and some of those covered with
coloured hairs form beautiful microscopic
objects. In the Order Compositae, its cha-
racters are used for the systematic division
of the numerous genera.

STIGMA' US, Koch.— A genus of Trom-
bidina (Acarina). Legs seven-jointed, ce-
phalothorax with transverse line ; no eyes.
S. cruentus, very minute. (Koch, Uebers. ;
Murray, EG. Ent. 124.)

STIGMAPH'ORA, Wallich.— A genus
of Diatomaceae.

Char. Frustules free, naviculoid j valves
lanceolate, loculate ; loculi with central and
marginal puncta ; marine. India.

BIBL. Wallich, Tr. Mic. Soc. viii. 43;
Rabenht. Alg. i. 258.

STIG'MATA OF ANIMALS. See SPIRA-
CLES.

STIGMATIDTUM, Mey.— A genus of
Graphidei (Lichenaceous Lichens). Apo-
thecia brownish, punctiform or elongate,
immersed, hypothecium colourless. (Leigh-
ton, Lick. Flora, 412.)

STIGONEMA, Ag.— A supposed genus
of Oscillatoriaceae, founded upon what has
proved to be the thallus of a genus of
Lichens. See EPHEBE.

STILBA'CEI.— Afamily of Hyphomyce-
tous Fungi, growing upon decaying animal
or vegetable matter, or on bark or leathery
leaves. Characterized by a receptacle com-
posed of conjoined filamentous or hexagonal

STILBOSPORA.

[ 730 ]

STING.

cells and spores borne singly on the apices
of free filaments, forming a gelatinous mass.
Some of the Fungi here included are hete-
rogeneous and imperfectly studied; for
example, Tubercularia and Fusarinm are
apparently only imperfect states of other
Fungi, while the more distinct genera ap-
pear to be referable to the family Dematiei.

Synopsis of British Genera.

Stilbitm. Receptacle stalked at the base?
clavate or capitate at the summit, com-
posed of coalesceut, densely crowded, paral-
lel filaments ; spores simple, arising singly
at the apices of free filaments.

Atractium. Stem firm. Head subglo-
bose ; spores fusiform, elongated.

Mi/rothecium. Receptacle at length mar-
ginate. Spores diffluent, oblong, forming a
fiat or slightly convex, dark green stratum.

Tubercularia. Receptacle wart-shaped,
globular or stalked, fleshy, composed of
continuous sterile, and thread-like beaded
fertile filaments. Finally indurated, floe-
cose, with the spores scattered over it, or
falling into powder.

Periola. Receptacle cellular, sessile;
fertile filaments abbreviated, torulose, mixed
with septate lax sterile filaments.

Volutella. Receptacle wart-like, cellular,
compact, with long, rigid bristles; spores
spindle-shaped, septate, on continuous short
filaments, arising all over the receptacle.

Fusarium. Receptacle wart-like, cellular,
gelatinous; spores spindle-shaped, simple,
somewhat curved, borne on simple filaments
arising all over the receptacle, and forming
a discoid stratum.

Illosporium. Receptacle wart-shaped,
subgelatinous, diffluent; spores simple, pel-
lucid, generally with a hyaline envelope,
borne on short filaments.

Epicoccum. Receptacle wart-shaped, cel-
lular, for the most part seated on an effused
patch ; spores four-sided, cellular, attached
sillily to very short, continuous filaments.

jEgerita, Spores irregular, disposed in
short moniliforni threads at the apices of
flexuous, branched, radiating, compacted
peduncles.

BIBL. Berkeley, Crypt. Botany, 311.

STILBOS'PORA, Pers. — A supposed
genus of Melanconiei (Stylosporous Fungi),
but apparently only consisting of stylospo-
rous fruits of SphceritR. These grow upon
wood, sticks, &c., breaking forth on the
surface without any distinct peritheciuni,

Fig. 700.

consisting of a nucleus
composed of aggluti-
nated (septate) stylo-
spores (see SPIIJERIA).
BIBL. Berk. 1>»:
Flor. ii. pt. 2. 356;
An. N. II. vi. 355;

Hooker's Jtl. of But. Stilbosporamacrosperma.

iii. 322; Fries, Sum .Group of eonceptack-s

breaking forth on a fi-ag-
Of

menfc Ofwood; nat. size.

. Z. Myc. ii. 63 ; The detached spores on
Till a «»n P An ffr Nut the right-hand magnified

luiasne, An. be. A at. 160aSinetew>
4. v. 109.

STIL'BUM, Tode.— A genus of Stilbacei
(Hyphomycetotis Fungi), containing a con-
siderable number of species, forming little
shining mildews, sometimes brightly
coloured, on decaying wood, herbaceous
plants, fungi, £c. The stalk-like stroma is
sometimes villous, sometimes glabrous and
rigid, sometimes pellucid and soft; it is
formed of conjoined filaments, the free ends
of which bear the spores in a capitulum,
which finally exhibits a gelatinous cha-
racter.

BIBL. Berk. Brit. Fl. ii. pt. 2. 330 ; Ann.
N. H. vi. 432, pi. 12 ; ib. 2. v. 465; Fries,
Sum. Veq. 469.

STILOPH'ORA, J. Ag.— A genus of
Sporochnaceae (Fucoid Algae), included by
some authors among the Dictyotaceae. There
are two British species, S. rhizodes and S.
Lyngbyei, characterized by a branched, fili-
form, at first solid, afterwards tubular frond,
the former 6 to 24", the latter 2 to 4" long,
arising from a small naked disk. The fruc-
tification consists of little wart-like bodies
scattered all over the frond, composed of
tufts of moniliforni filaments, at the bases
of which are attached either pyriform uni-
locular, or tubular septate sp oranges. Thu-
ret states that the specimens of S. rhizodes
found a certain distance above low-water
mark appear mostly to bear septate, those
always under water simple sporanges, and
those in an intermediate position exhibit
both. The plants of the first kind are of
paler colour than those of the second.

BIBL. Harvey, Mar. Ale/. 39, pi. 7 C ;
Greville, Alg. Brit. pi. 6; thuret, Ann. So.
Nat. 3. xiv. 238, pi. 38.

STING OF INSECTS.— The well-known
sting of the females or so-called neuters of
Hymenopterous Insects, as the honey-bee,
the humble-bee, the hornet, the wasp, &c.,
appears to the naked eye to be a single
needle-like organ ; but when examined un-
der the microscope, it is seen to consist of
3B2

STINGS.

C 740 ]

STINGS.

three pieces — a short, stout, cylindrico-coni-
cal outer piece or sheath (PL 34. fig. 14 a),
cleft throughout its length on the under
surface and obtuse at the end, within which
are partly contained two long elbowed setae
or lancets (PI. 34. fig. 15, one of them),
thickened and furnished with teeth directed
backwards near the end of one margin, the
other margin sharp and cutting. These setae
play within the sheath, being partially pro-
trusile and retractile, as is the sheath itself.
The poison-apparatus consists of two glan-
dular elongated sacs, either simple (PL 34.
fig. 14 <?,/), or branched as in the humble
bee, &c., and terminating by one (fig. 14 d) or
two ducts, in a muscular reservoir (fig. 14 c),
from which an excretory duct runs to the
base of the sheath of the sting.

The irritation produced by the sting of one
of these insects needs no remark. It does not,

however, serve a merely defensive purpose,
but is used also to paralyze the prey, so that
it may be kept in store for future use.

The sting represents a modified ovi-
positor.

BIBL. Lacaze - Duthiers,
Ann. Sc. Nat. 3. xii. xiv.
&c. ; Westwood, Introd. ; Sie-
bold, Vergl. An.

STINGS OF PLANTS. —
These are epidermal struc-
tures, consisting of large hairs,
with a bulbous base more or
less included in a cellular
coat/and attenuated upwards.
In the sting of the nettle the
apex is expanded into a little
bulb, which is broken off when
the sting is lightly touched M 20di'amB
(PL 28. fig. 8). Young stings

Fig. 702.

Fig. 703.

Fig. 704.

Fig. 702. Gastric mucous gland with cylinder-epithelium, from the pylorus of a dog. a, principal cavity;
b, tubular processes arising from it. Magnified 60 diameters.

Fig. 703. Gastric peptic gland from the middle of the stomach, a, principal cavity ; b, primary, and c, terminal
branches arising from it. Magnified 60 diameters.

Fig. 704. Portions of a terminal branch, the upper representing a longitudinal, the lower a transverse section,
a, basement membrane; b. large cells in close apposition with it; c, smaller epithelial cells surrounding the
cavity.. Magnified 350 diameters.

STIPA.

[ 741 ]

STOMATA.

exhibit the ROTATION. Stings occur not
only in the nettles (Urtica), but in the
cultivated Loasaceae (Loasa, Bartonia, &c.),
and of much larger size in some exotic
Urticaceas and Euphorbiaceae.

See HAIRS, page 378.

STI'PA, Linn. — A genus of Graminaceae.
The fibres of the culms of S. tenacissima
are used in the manufacture of paper.

STOMACH.— The glands which secrete
the gastric juice, or the peptic glands, are
tubular, and placed perpendicularly beneath
the surface of the mucous membrane, and
extending as deeply as the muscular coat of
the stomach.

They vary in length from 1-60 to 1-12",
are cylindrical, somewhat narrowed towards
the closed end, which is rounded or some-
what inflated. The lower third is wavy or
spiral, especially in the glands occupying the
pylorus ; some of them also give off a caeca!
branch.

The peptic glands consist of a delicate
basement membrane, lined in the upper
third with cylindrical epithelium, the lo'wer
portion being filled with large, pale, poly-

Perpendicular section of the pyloric portion of the
stomach of a pig. a, glands; 6, muscular layer of the
proper mucous membrane; c, submucous tissue with
the orifices of divided vessels ; d, transverse muscular
layer; e, longitudinal ditto; f, serous coat. Magnified
30" diameters.

gonal, finely granular cells, not arranged in
a laminated form.

In many animals the gastric glands are of
more complicated structure than in man, and

two distinct kinds exist — in one, secreting
mucus, the tubes being lined with cylin-
drical epithelium; whilst in the other, which
secretes gastric juice, rounded epithelial
cells occur, and the walls are expanded at
intervals.

Closed follicles , resembling the solitary
glands of the small intestines are met with
in the stomach ; they are inconstant, how-
ever, and variable in number.

The stomach is lined by cylindrical epi-
thelium.

BIBL. Kolliker, Mik. An. ii. 137, and the
Bibl. therein ; Todd and Bowman, Phys. An.
$c. ; Brinton, TodcTs Cycl. An. 8f Phys. Art.
Stomach ; Klein, Strieker's Hist. i. 343.

STOM-A.TA (plural of STOMA).— The
name applied to the structures which con-
stitute the passages of communication,
through the EPIDERMIS of plants, from the
intercellular passages to the external air.
They occur almost exclusively on the green
parts of plants, and are usually absent from
the epidermis of roots, and the surface of
all structures growing under water. The
lowest classes which present them are the
Liverworts and Mosses, where, however,
they are limited to a few kinds, and in the
former present a peculiar organization. In
the Ferns they are distributed just as in
the Flowering Plants, where they occur
principally upon the leaves (fig. 706),
especially upon the lower face, but ex-
tend also over the green shoots, the parts
of the flower (fig. 200, page 296), and even
into the interior of cavities, as on the epi-
dermis of the replum of Cruciferse (wall-
flower), and still more remarkably on the
epidermis of seeds (skin of the walnut).

In the Liverworts the stomata occur on
the fronds and receptacles of certain genera
(Marchantia, Fegatetta, &c. &c.). In Mar-
chantia (fig. 447, p. 489), they are somewhat
circular orifices in the epidermis, guarded
by cells arranged in three or four tiers. In
the Mosses they are met with on the apo-
physes or thickened summits of the setaa
bearing the capsules, as in Funaria (fig. 262,
page 343). The structures here resemble
those in the higher plant/, as is the case
also with those on the leaves of Ferns.

In the Flowering Plants the perfect sto-
mata appear as roundish or sometimes
squarish chasms in the epidermal layer,
occurring regularly at the meeting angles
or sides of four or more epidermal cells, the
chasm forming an orifice leading down to a
subepidermal intercellular space, and guar-.

STOMATA.

L 742 ]

STOMATA.

Epidermis of the White

ded a little below the upper edge, more
deeply, or even at the bottom, by usually
two semilunar cells, applied together by
their flat faces, but not coherent, their con-
vex surfaces adhering firmly to the sides
of the epidermal gap. According as the
two stomatal cells —
pore-cells or guard Fig. 706.

cells — are distended
or collapsed, their
flat faces approach
or retreat from each
other, in the latter
case leaving a slit-
like orifice leading
from the outer pas-
sage into the subepi-
dernial space. Some-
times the guard
cells are four in
number, in which
case they either form
two tiers, as upper
and lower (Prote-
aceae, e. g. Hakea,

Protect, &C.), Or they Lil/ with stomata st (lower

are in the same line B™ ace?' , in
and parallel, form- Magnitied 10° diamefcer8'
ing inner and outer guard cells (Ficus
elasticci). In certain coriaceous leaves the
stomata are placed on the sides of pits ex-
cavated beneath the surface of the leaves,
as in Dasylirion longifolium and Nerium
Oleander.

A considerable difference exists between
the appearances presented by vertical sec-
tions of the epidermis of leaves made so as
to pass through the stomata. In young
leaves the guard cells are little (if at all)
below the general level of the epidermis ; and
the same is the case with the perfect forms
of various herbaceous plants in which the
leaves are of membranous texture. In other
cases, as in the Hyacinth, Iris, Narcissus,
Equisetum, &c., the guard cells are found at
a very early period quite beneath the layer
of epidermal cells, attached as it were
under the passage communicating with the
air. The same occurs very frequently in
the stomata of coriaceous leaves, as in Aloe
(PI. 48. fig. 22), Ficus, Cijcas, Hakca, Protea,
&c. In other instances also in leathery
leaves, the guard cells appear more or less
elevated above the general level of the
epidermal cells, as in some species of Leu-
cadendron, Grevillea, &c. It is important to
observe that in the cases where the guard
cells are sunk in the orifice of the epidermis,

the upper margin of the orifice, formed by the
borders of the surrounding epidermal cells,
sometimes becomes elevated and even con-
verted into a kind of perforated dome (PI.
48. fig. 22) by development of the cuticular
layers (see EPIDERMIS). This might be
mistaken for the stoma itself. The same
cuticular substance is often developed in
mature leaves, not only down over the walls
of the stomatal passage, but over the guard
cells, and thence more or less into contiguous
intercellular passages. This may be observed
in Euphorbia Caput-Mcdusce, Helleborus
niyer and viridis, Betula alba, Asphodelus
luteus, and Cereus, some Aloece, &c. Gas-
parini obtained these connected processes of
cuticular substance, in the form of an
isolated coherent piece, by boiling epidermis
in nitric acid, which dissolved the adjoining
cell-walls : these he mistook for peculiar
organs, and called them, cystomes. Hooker
has described a remarkable form of stomata
in the parasitical plant Myzodendron.

In those plants in which the epidermis
becomes infiltrated with siliceous matter, the
walls of the stomatal pore and the guard
cells become imbued with it, and a sili-
ceous skeleton of the structure remains after
the organic matter has been removed by
nitric acid and burning (PI. 48. fig. 29).
This is readily seen in the Equisetacese,
especially E. hyemale, also in the Grasses.

The mode of development of the stomata
appears to be uncertain. Mohl and other
authors assert that the guard cells origi-
nate from one of the cells of the subepi-
derinal tissue, which is pushed up into a
vacancy formed by the separation of the
epidermal cells at certain points. This cell
is next divided into two, which become
free from each other in the line of the new
partition then formed. Nageli and others
assert that the guard cells are originally
constituent cells of the epidermal layer,
which become subsequently displaced down-
wards (or upwards), and undergo special
development analogous to that just de-
scribed. In the Iridaceae,Equisetace8e, and
some other plants, the process is more com-
plicated.

The stomata are generally largest upon
succulent leaves, smallest on hard and
leathery kinds ; their form and number are
most varied, both in different plants and on
different parts of the same plant. They
abound most on the lower face of leaves ;
but it has been mentioned that they are not
found on submerged organs, and on floating

STOMATA.

[ 743 ]

leaves they occur only upon the upper face.
The larger kinds are moro scattered on
a given surface ; the smaller occur closer
together: this depends, of course, on the
general character of the epidermal and sub-
jacent tissue. The numbers have been
estimated upon the surfaces of many leaves,
of which a few examples may be given :
thus a square inch contains, on the

Upper surface. Lower surface.

Carnation 38,500 .... 38,500

Garden Flag .... 11,572 .... 11,572

House-leek .... 10,710 .... 6,000

Tradcacantia 2,000 2,000

Mistletoe 200 .... 200

Holly 0 .... 63,600

Lilac 0 ....160,000

Vine 0 .... 13,600

Laurestinus 0 90,000

BIBL. General Works on Struct. Botany ;
Mirbel, Mem. Ac. Roy. France, xii. ; Gas-
parini, Nuove ric. 8. strutt. d. Cistomi, 1844 ;
Garreau, Ann. Sc. Nat. 4. i. 213 ; Hooker,
Flora Antarct. \. 291 ; Biscoe, Mn. Mic. Jn.
viii. 31. ; Hohnfeldt, Bot. CentralU. 1880, i.,
Jn. Mic. Soc. 1881, i. 71 (underground) ;
Prantl, Flora, 1872 ; Stein, Bot. 103.

STOMATA or STIGMATA of Animals.—
These are minute rounded spaces, left be-
tween the epithelial cells of the capillary
blood-vessels, lymphatics, and of the serous
membranes. Great importance has been
attributed to them, as allowing the escape
of the corpuscles and liquid into the sur-
rounding tissues. This may occur when the
vessels are congested and distended; but
not in the normal state, for the finest injec-
tions do not escape through them. They are
best seen in silver-stained preparations.
(Frey, Hist, and the Bibl.)

STOMATOP'ORA=ALECTO.

STONES OF FRUITS, such as cherries,
plums, &c., afford excellent materials for
sections, showing extreme development of
the woody SECONDARY DEPOSITS of vege-
table cells.

STORTHOSPH^E'RA, Schulze.— A glo-
bular Arenaceous Foraminifer with a short
blunt spike. German Ocean. (F. E. Schulze,
Commiss. wiss. Un.deutsch. ^f<?ere,1875,113.)

STRIA'RIA, Grev.— A genus of Dictyo-
siphonacese (Fucoid Algae), nearly related to
Punctariaceae, having a branched, filiform
pale olive, tubular frond, arising from a
shield-shaped naked disk. The walls of the
tube are membranous, and the cavity with-
out septa. S. attenuata (fig. 707) grows from

STRIATELLA.
Fig. 707.

Striaria atfcenuata.
Fig. 707. Part of a frond. One-third of the nat. siz«.

Fig. 708.

Fig. 709.

Striaria attenuata.

Fig. 708. A fragment with sori. Magnified 5 diams.
Fig. 709. Section of a fertile branch, with sori. Mag-
nified 25 diameters.

3 to ] 2" high. The branches are attenuated
towards each end, and marked with rings
consisting of clusters of simple sporanges
(spores) (fig. 708), sometimes accompanied
by filaments (fig. 709).

BIBL. Harv. Mar. Alg. 41 ; Grev. Alg. 54.

STRIATEL'LA, Ag.— A genus of Dia-
tomaceae.

Char. Frustules with a stipes attached to
one angle, depressed, tabulate ; with longi-
tudinal uninterrupted vittae, apparently
thickened at each end. Marine.

The vittae appear as dark lines j no trans-
verse striae are visible under ordinary illumi-
nation.

8. unipunctata (PI. 17. fig. 20), Frustules
in front view quadrangular, often broader
than long, lateral margins subulate ; valves
narrowly lanceolate j stalk elongate, simple,
filiform and thickish. Length of frustules
1-450 to 1-280".

STRIGULA.

C 744 ]

STYLONICHIA.

BIBL. Kiitz. Badll 125 : Sp. Alg. 114 ;
Rabenht. Alg. i. 307 ; Grunow, M. M. J.
xviii. 171.

STRIG'ULA, Fries.— A genus of Pyre-
nodei (Lichenaceous Lichens), containing
one British species, S. Babmgtonii, growing
on the leaves of box and other evergreens.
Thallus subepidermal ; asci containing eight
cymbiform triseptate spores.

BIBL. Leighton, Lich. Fl 498; Berk.
Eng. Bot. Supp. pi. 2957.

STROMBID'IUM, 01. & Lach.— A ge-
nus of Peritrichous Infusoria/am. Halterina.

Char. No setae for leaping, essentially
swimmers. 8 species; marine and fresh-
water. (Cl. & Lachm. Inf. 371; Kent,
Inf. 631.)

STROMBIDINOP'SIS, Kt.— A genus of
Heterotrichous Infusoria. Free, ovate,
ciliated; anterior cilia longer, forming a
wreath of one or more turns. S. gyrans ;
freshwater; length 1-350". (Kent, Inf.GU.)

STRONG YLIDTUM, Sterki.— A genus
of Hypotrichous Infusoria. Like Uroleptus
jriscis, but with a thicker twisted body, and
frontal and anal styles. (Kent, Inf. 779.)

STRON'GYLUS, Miill.— A genus of
Nematoid Entozoa. The species are very
numerous. 8. pergracilis is the cause of the
grouse-disease. S. sanguisuga is allied to
Anchylostoma, inhabits the human small
intestine, sucking the blood and producing
anaemia. (See the BIBL. of ENTOZOA, and
Dounon, Parasites.)

STRONTIA OB STRONTIAN. — The
crystals of the sulphate of this earthy base
are figured in PI. 10. fig. 18, to contrast with
those of the sulphates of baryta and lime.

STRUTHIOP'TE- Fig. 710.

RIS, Will den. = Ono-
clea, pt. — S. (Onoclea)
germanica, fig. 710.

STRYCHNINE,or
STRYCHNIA. See AL-
KALOIDS, p. 31.

STYLOBIB'LI-
UM, Ehr. — A genus
of fossil Diatomaceae.
Char. Frustules
circular, single, com-
pound; valves con-
tiguous, in a single Struthiopteris germanica.
rn-w lilrp fhp Ipflvfq nf Portion of a pinna with the

row, iiJ«r tne iea\ es 01 rolled ^ coverin the
a book, the inner ones 8ori.

with a large median Magnified 40 diameters.

aperture (?),the outer

not being perforated but sculptured.

8. clypeus (PI. 18. fig. 50 a, b) ; S. divisum

(fig. 50 c) ; 8. eccentricum (fig. 50 d). It is
uncertain whether the so-called inner valves
are merely hoops, or the valves of imperfectly
separated frustules ; also whether they are
perforated or not, for neither Ehrenberg nor
Kiitzing can be relied on for distinguishing
a perforation, as evidenced by their erroneous
description of the structure of the valves
of Pinnularia, Grammatophora, and many
other Uiatomaceae.

Three species are described, occurring in
America and Siberia. The sculpturing s
upon the outer valves consist of radiating
or excentric curved lines.

BIBL. Ehr. Her. Berl. Ak. 1845; id.
Mikrog. ; Kiitz. Sp.Alg. 16; Rabenht. Alg.
i. 302.

STYLOB'RYON=_Dmo5n/<w pt.
STYXOCHO'NA, Kt.— Like Spirochona,
but with distinct stalks. 2 species ; on
Nebalia and Gammarus. (Kent, Inf. 662.)
STYLOCHRYS'ALIS, Stein.— A genus
of Flagellate Infusoria. Ovate, pedicled ;
flagella 2, equal ; two lateral pigment-bands ;
freshwater. S. parasita, on Eudorina ele-
gans. (Kent, Inf. 405.)

STYLO'COLA, De From.— A genus of
Peritrichous Infusoria. Body as in Vagi-
nicola, but attached to the sheath by nume-
rous fibres. Two species; freshwater. (Kent,
Inf. 730.)

STYLONE'THES, Sterki.— A genus of
Hypotrichous Infusoria. S. tardus. (Kent,
lK/782.)

STYLONICHIA, Ehr.— A genus of Hy-
potrichous Infusoria, fam. Oxytrichina.

Char. Body ciliated, and furnished with
styles and hooks.

In this genus, transverse and longitudinal
division, gemmation, and the encysting pro-
cess have been observed.

S.mytilus=Kerona mytilus, D. (PI. 31.
figs. 27, 28). Body white, hyaline at each
end, flat, oblong, slightly constricted in the
middle, dilated at the oblique fore part ;
freshwater ; length 1-240 to 1-100".

S. pustulata—Eerona pustul. D. (PI 31.
fig. 26). Body white, turbid, oblong, with
a median ventral band of hooks ; fr. wat. ;
length 1-144".

8. histrio (PI. 31. fig. 29). Body white,
elliptical-oblong, hooks aggregated into an
anterior heap ; no setae ; fr. wat. ; length
1-290 to-1220"; probably a variety of ' S.
pustulata.

S. lanceolata (PI. 31. fig. 30). Body
lanceolate, pale green, obtuse at the ends ;
ventral surface flat; hooks acervate near

STYLOPLOTES.

[ 7r> ] SUDORIPAROUS GIANDS.

the mouth: styles none; fr. wat. ; 1 ngth
1-140 to 1-20''.

BIBL. Ehr. Inf. 370 ; Stein, Inf. ; Clapa-
rede et Lachm. 'inf. 1S4; Kent, Jn/. 71)0.

STYLOPLO'TfiS, Stein = Stylonichia pt,

STYLOSPOR'EI.— Thesefungi were for-
merly included in the CONIOMYCETES ; but
their external resemblance to the PYRENO-
MYCKTES, of which they are indeed forms,
makes it desirable to give them a separate
name.

STY'LOSPOKES.
— Stalked spores of
Coniomycetous Fun-
gi, usually compound
or septate, then pro-
bably consisting of a
row of independent
spores connected by
an adherent parent
sac — thus, structur-
ally, metamorphosed
asci ; they are some
times appendaged
above (fig. 711) (aee StylosporesofPestalozzia.
SPORES and CONIO- Magnified 200 diameters.
MYCETES).

STYSA'NUS.— A genus of Dematiei
(Mucedinous Fungi), characterized by a
stem consisting of an aggregation of threads,
bearing above at their extremities simple or
necklaces of spores. S. Caput-Medusce
(fig. 346, p. 406).

Fig. 712.

SUBLIMATION.— The application of
this process in the detection of arsenic and
antimony is alluded to at p. 73 ; but its
utility has been further shown in regard to
several other inorganic and organic sub-
stances— a little of the substance being
placed in a cup-like hollow in a piece of
platinum-foil, a cover laid on, and heat
applied until fusion and sublimation takes
place, when the characteristic crystals are
found (ALKALOIDS).

BIBL. Guy, Pharm. Jn. 2. viii. & ix. ;
Helwig, D. Mikr. in d. Toxicologie, 1865,
64 microphotographs.

SUCCINIC ACID.— This acid, which
occurs in amber, in all fermented liquids,
and in the contents of JEchinococcus-cysts,
is pretty soluble in water, readily in hot but
with difficulty in cold alcohol, and but little
in ether. The crystals belong to the ob-
lique prismatic system, and are represented
in PI. 11. fig. 21.

BIBL. That of CHEMISTRY.

SUDORIP'AROUS GLANDS.— These
organs secrete the perspiration.

They are found in most parts of the skin,
but in variable numbers in different locali-
ties. Thus it has been estimated that 417
exist in a square inch of the skin of the back
of the hand, 1093 in an inch of the outside,
and 1123 in the inside of the forearm, and
2736 in an inch of the palm of the hand.

Each gland consists of a long tube coiled

Fig. 713.

Fig. 712. A sudoriparous gland, with its blood-vessels, a, proper gland; 6, duct; c, blood-vessels of a gland
Magnified 35 diameters.

Fig. 713. Portion of the tube foiming a sudoriparous gland from the hand, a, areolar coat ; b, epithelium ;
c, cavity. Magnified 360 diameters.

SUDORIPAROUS GLANDS. [ 746 ]

SYCAMINA.

into a knot near the closed end, which is
situated in the subcutaneous cellular tissue,
and forms the gland proper, and a straight,
undulate or spiral duct, which traverses the
skin perpendicularly, to terminate upon its
surface between the papillae.

In the glands of the axilla, the portion
of the tube forming the gland proper is
branched ; and sometimes the branches ana-

stomose.

Portion of a tube with a muscular coat, from the scro-
tum, a, connective tissue ; 6, muscular layer ; c, epi-
thelial cells, filling the tube and containing yellow
granules. Magnified 350 diameters.

The coiled portion or proper gland is sur-
rounded and permeated by an elegant plexus
of capillaries ; and some of them are sur-
rounded by a capsule of connective tissue
with spindle-shaped cells.

The tube of the glands exhibits two forms
of structure. In one of these there is^an
outer coat of indistinctly fibrous connective
tissue with elongated nuclei, sharply defined
internally by probably a basement mem-
brane, this being lined with one, two, or
more layers of polygonal pavement-epithelial
cells, mostly containing fat-globules and
pigment-granules.

In the other form, the fibrillation of the
connective coat is tolerably distinct, the
fibres longitudinal, sometimes also with an
inner, delicate transverse layer, and both
containing nuclear elastic fibres ; and within
this coat is a layer of longitudinal, unstriped
muscular fibres.

The portion of the ducts traversing the
cuticle is spiral.

It is by no means an easy matter to ob-
tain the sudoriparous glands in the entire
state. The skin of the palm of the hand or
the paw of a dog is best for the purpose j
and before making sections with a Valen-
tin's knife, the structure should be mace-
rated in a mixture of 1 part nitric acid and
2 of water, or in solution of carbonate of
potash.

BIBL. Koliiker, Mik. An. ii. ; Todd and
Bowman, Phys. An. : Biesiadecki, Strieker's
Hist. ii. 238.

SUGAR.— This substance is liable to
fraudulent adulterations; and the coarser
kinds of brown sugar contain many im-
purities, such as Acari, fragments of the
cane, &c. Starch and flour are used to
whiten and give dryness to inferior moist
sugar ; and these may be detected by the
microscope (STARCH).

The crystals of sugar of milk are repre-
sented in PL 10. fig. 12 ; and those of dia-
betic sugar in fig. 13. (Hassall, Food $c. 12 j
and the Bibl. of CHEMISTRY.)

SURIREL'LA, Turpin.— A genus of
Diatomaceae.

Char. Frustules free, single, ovate, ellip-
tical, oblong, cuneate or broadly linear in
front view; valves with a longitudinal
median line or a clear space, the margins
winged, and with transverse or slightly
radiating canaliculi or tubular striae.

It appears that in the valves the margins
of the depressions are fused together to
form tubular channels open at the ends.

S. bifrons (Ehr. 1833 = & biseriata, Bre'b.
and Smith) (PI. 17. fig. 22). Frustules in
front view broadly linear, with rounded
angles ; valves elliptic-lanceolate, somewhat
obtuse ; alae and canaliculi distinct ; fresh-
water ; length 1-180 to 1-96".

S. gemma (PI. 17. fig. 21). Frustules
ovate ; valves elliptic-ovate ; canaliculi nar-
row, inequidistant ; marine ; length 1-240".

S. splendida. Frustules ovato-cuneate,
ends rounded ; valves ovato-lanceolate ; alae
and caualiculi distinct; freshwater; length
1-100".

BIBL. Smith, J5r. Diatom, i. 30 ; Kiitz.
Bac. 59, and Sp. Alg. 34 ; Rabenht. Ala. i.
51.

SWARMING.— This term has been ap-
plied, from comparison with the swarming
of bees, to the remarkable oscillating
crowding movements of the spores of Con-
fervae &c. while free in the cavity of the
parent cell and preparing to break forth.

The spores are hence often called "swarm-
ing-spores." See HYDRODICTYON.

SYCAMI'NA, v. Tieg.— A genus of
Volvocineae, composed of very minute
spherical, biciliated cells, associated in large
numbers to form a mulberry-like revolving
mass, the protoplasm being black or brown,
sometimes violet or reddish. S. nigrescens,
found at the bottom of ponds and aquaria,
forming a dark deposit, and producing the

SYENITE.

f 747 ]

SYNDENDRIUM.

decomposition of the organic matter.
Reproduction by fission, and formation of
resting spores. (V. Tieghem, Butt. Soc. Bot.
J'V. LSSO. l>73; Jn. Mic. Soc. 1881, i. 97.)

SYENITE. See ROCKS.

S V M BIOTES = CHOBIOPTES.

SYMBOLOPH'ORA, Ehr.— A genus of
Diatomacen.

Char. Frustules single, disk-shaped, with
incomplete septa radiating from the solid
angular centre, and intermediate bundles
of radiating lines. Marine and fossil.

S. Trinitatis (PL 25. fig. 6). Valves
with a triangular umbilicus, the transparent
margins of which are crenulate, the rest
of the disk covered with six bundles of
very fine radiating lines. Diameter 1-2.30".
America.

S. acufa (PL 18. fig. 54) ; S. micrasterias
(fig. 55) ; S. pentas (fig. 56).

BIBL. Ehr. Her. Berl Ak. 1844, 74 j
Kiitz. Sp. Ala. 131.

SYMPHYOSI'PHON, Kiitz. = Scyto-
ncma pt.

SYM'PLOCA, Kiitz.— A genus of Oscil-
latoriacese (Confervoid Algae), perhaps not
distinct from Symphyosiphon.

SYrNALIS'SA.— A genus of Collemei
(Collemaceous Lichens), somewhat resem-
bling Lichina, but with open apothecia.
(Leighton, Lich. Fl. 13.)

SYNAP'TA, Eschsch.— A genus of ver-
miform Echinodermata.

The species of Synapta, which are not
British, are of special microscopic interest,
on account of the presence in their skin of
remarkable anchor-shaped calcareous spi-
cula, the bases of which play in perforated
plates. These are situated upon minute pa-
pillae of the skin, and serve to aid in loco-
motion and adhesion.

BIBL. V. d. Hoeven, Zool. i. 150 ; Vogt,
Zool Briefe, i. 168 ; Quatrefages, Ann. Sc.
N. 2. xvii. 19 ; Gegenbaur, Vergl. An. 216 ;
Herapath, Qu. Mic. Jn. 1865, 1.

SYNCEkE'TA, Ehr.— A genus of Rota-
toria, of the family Hydatinaea.

Char. Eye single, cervical, rotatory organ
furnished with styles; foot forked; jaws
each with a single tooth.

Some of the species are furnished with
one or more so-called crests, which in some
appear to correspond to the calcar.

S. baltica (PL 44. fig. 26). Body ovate ;
rotatoiy lobes four ; styles four ; a single
median sessile crest; marine; length 1-108".
Phosphorescent. Three other species. (Ehr.
In/us. 436.)

SYNCIIIT'RIUM, De Bv. & Woronin.—
A genus of parasitic Unicellular Alga),
allied to CHYTRIDIUM, found under the
epidermis of the leaves of Taraxacum and
Succisa, and composed of aggregated orange-
yellow cells, enclosed in an envelope, form-
ing sori.

BIBL. Rabenht. Aty. Hi. 284.

SYNCORY'NE, Ehr. (par*).— A genus
of Corynidae (Hydroida).

BIBL. Allman,.4n». N. H. 1864 ; Hincks,
Hyd. Zooph. 48.

SYNCRYP'TA,Ehr.— A doubtful genus
of Volvocineae (Confervoid Algaa), composed
of organisms consistingof a hyaline spherical
gelatinous envelope, enclosing a number of
ovate green bodies placed at the periphery,
and sending out a pair of free vibratile cilia
from the surface of the envelope. Green
bodies not attenuated at the posterior ex-
tremity ; no eye-spot. S. Volvox (PL 7.
fig. 14*6), globe 1-576" in diameter, bodies
1-2880" long; freshwater. This object,
which we have observed in company with
those represented in figs. 14 «, 31 and 32 of
the same plate, is most probably a young
specimen of either Volvox or Pandorina.
Kent places it among the Flagelliforna In-
fusoria.

BIBL. Ehr. Inf. 60 ; Kent, Inf. 413.

SYNCYC'LIA, Ehr.— A genus of Diato-
maceae.

Char. Frustules cymbelliform, united in
circular bands, immersed in an amorphous
gelatinous substance. Marine.

The nodules appear to be the same as
those of Cymbella.

S. salpa (PL 19. fig. 14). Frustules
semiovate, unstriated (ord. ilium.), com-
monly six together, united into a ring ; en-
dochrome bright green.

S. quaternaria. Frustules two or four
together ; endochrome yellow or reddish ;
length 1-860".

BIBL. Ehr. Inf. 233; Ber. Berl. Ak.
1840, 32 ; Kiitzing, Sp. Alg. 61 ; Rabenht.
ALg. i. 97.

SYTTOEN'DRIUM, Ehr. -A genus of
Diatomaceaa.

Char. Frustules single, subquadrangular,
destitute of a median umbilicus ; valves
unequal, slightly turgid — one smooth, the
other with numerous spines or little horns
branched at the ends, situated upon the me-
dian flat portion, the margins being free
from them.

S. diadema (PL 18. fig. 59). Frustules
lanceolate ; spines five or six, bifurcate or

SYNECHOCOCCUS.

[ 748 ]

SYNTETHYS.

tufted at the end, as long as the frustules
are broad. Breadth 1-1150". Found in
Peruvian guano.

BIBL. Ehr. Ber. Bei'l Akad. 1845, 155;
Kiitz. Sp. Alg. 141; Pritchard, In/us. 866.

SYNECH'OCOC'CUS, Nag.— A genus of
Unicellular Alga3.

Char. Cells minute, oblong, single or con-
joined in rows of 2-4 ; dividing in one di-
rection only; endochrome Eeruginous or
yellowish.

S. ceruginosus (PI. 3. fig. 2(1). Common
on damp rocks and banks. (Rabenht. Alg.
ii. 59.)

SYNE'DRA, Ehr.— A genus of Diato-
niacea3.

Char. Frustules prismatic, rectangular,
or curved ; at first attached to a gelatinous,
sometimes lobed cushion, subsequently often
becoming free; valves linear or lanceolate.

The valves usually exhibit a longitudinal
line, with a dilated median and two termi-
nal nodules ; they are also generally covered
with transverse strias ; in some species the
median line and appearance of a median
nodule correspond to a clear space, free
from the transverse striaB.

Species very numerous.

8. radians, Sm. (splendens, K.) (PI. 17.
fig. 23 a, 6, c). Frustules elongated, in front
view dilated and truncate at the ends ;
valves gradually attenuated from the mid-
dle to the obtuse ends. Freshwater ; com-
mon; length 1-70". Frustules radiate upon
the cushion.

S. fulgens (Licmophora fulg. K.) (PI.
17. fig. 24). Frustules linear ; valves slightly
dilated in the middle and at the rounded
ends, arranged in a fan-shaped manner upon
the branched cushion. Marine ; length
1-120".

S. capitata (PI. 17. fig. 25). Frustules
linear, truncate, ends slightly dilated; valves
linear, ends dilated into a triangular head.
Freshwater ; length 1-60".

BIBL. Smith, Br. Diat. i. 69; Kiitz.
Sp. Alg. 40; Rabenht. Alg. i. 126; Gru-
now, M. M. Jn. xviii. 166.

SYN'GAMUS, Lieb.— A genus of Nema-
toid Entozoa. S. trachealis is very common
in the trachea of poultry, producing the
"gapes." (Dujardin, Helminthes, 260; Sie-
bold, Wiegmanrfs Arch. 1835; Cobbold,
Paras.)

SYNOVIAL MEMBRANES.— In minute
structure these resemble serous membranes.

Synovial membranes are occasionally fur-
nished with appendages, some of which

contain fatty tissue, others abound in capil-
laries and form fringes where the synovial
membrane is attached to the articular car-
tilages. The latter consist of a basis of
indistinctly fibrous connective tissue, co-
vered by the synovial epithelium, with a
few fat-cells, sometimes isolated cartilage-
cells, and the capillaries. Attached to their
margins are flattened, conical, stalked,
smaller appendages (fig. 715), seldom con-
taining blood-vessels, and composed of indi-
stinctly fibrous areolar tissue, with scattered
cartilage-cells, and a thick epithelial layer ;
while some of the smaller ones consist
almost entirely of epithelial cells or of
areolar tissue.

Fig. 715.

From he synovial membrane of a finger-joint.

A. Two appendages of the synovial processes, a,
areolar tissue in its axis ; b, epithelium of the free
margin : c, that continuous with the epithelium of the
processes ; d, cartilage-cells. Magnified 250 diameters.

S. Four epithelial cells from the synovial membrane
of the knee-joiut, one of them with two nuclei. Magni-
fied 350 diameters.

BIBL. Brinton, Todd's Cycl. An. fy Phys.
art. Serous Membranes ; Albert, Sti'icker's
Hist. iii.

SYN'TETHYS, Forbes.— A genus of
Tunicate Mollusca, of the family Botryllidae.

Char. Mass sessile, gelatinous, forming a
single system ; animal sessile, having simple

SYNURA.

[ 749 ]

TABELLARIA.

orifices, without rays. One species : S. He-
bridicw.

BIBL. Gosse, Mar. Zool. ii. 34.

SYNU'RA, Ehr.— A doubtful genus of
Volvocineae (Confervoid Algae), consisting
of a number of oblong corpuscles attached
together by their prolonged filiform pos-
terior extremities to form a globe ; flagella
two ; no eye-spot. In S. Uvella the corpus-
cles are yellowish, the tails three times as
long as the bodies ; diameter of globea
1-iW. SeeVoLvox. (Ehr. Inf. 6 ; Kent,
////. 411.)

SYRINGID'IUM, Ehr. — A genus of
Diatomaceae.

Char. Frustules single, terete; valves acu-
minate at one end, two-horned at the other.
Marine.

8. btcorne (PI. 18. fig. 32). Frustules
oblong, smooth, not striated, turgid in the
middle, one end attenuate, with two slight
constrictions, and acuminate, the other sub-
globose, turgid, and with two horns. Length
1-370". Coast of Africa.

&0ofemo»(PL 18. fig. 33).

BIBL. Ehr. Ber. Berl. Ak 1845, 365;
Kiitz. Sp. Alg. 32 ; Pritehard, Inf. 866.

SYRINGOSPR^E'RIDyE, Duncan. —
An extinct Order of Rhizopoda. Free,
globular, sometimes 3" in diameter, consist-
ing of congeries of tubes (1-1000 to 1-300
inch), in radial groups, with an interradial
reticulation of inosculating tubes, some of
which appear at the surface. Syringo-
spheera, 5 species, and Stoliczkaria, 1 species,
Triassic (?), N. India, known as "Kara-
koram Stones."

BIBL. Duncan, Ann. N. If. 5. ii. 297;
Yarkand Miss.IS79 ; Qu.J. Geol. S. xxxviii.
60

^SYSTEPHA'NIA, Ehr.— A genus of
Diatomaceae.

Char. Frustules circular ; valves alike,
areolar, neither radiate nor septate, with a
crown of spines or an erect membrane on
the outer surface of each valve (not on the
margin). Fossil.

8. corona (PI. 18. fig. 57); 8. diadema
(fig. 58).

One other species ; found in Bermuda.

BIBL. Ehr. Ber. Berl. Ak. 1844, 264;
Kiitz. Sp. Alg. 126 ; Pritchard, Infus. 832.

SYZYGITES, Ehrenberg (see PHYCO-
MYCES). — A genus of Mucorini (Phycomy-
C3tous Fungi), containing two species, a
kind of mould growing over decaying
Agarics, remarkable among all the class to
which they belong for the occurrence of the

phenomenon of conjugation of the branches
as a preliminary to the formation of the
spores. Ehrenberg discovered the conju-
gation in S. megalocarpus many years ago.
The young filaments are simple, slender,
rather rigid, pellucid and straight, — soon
becoming forked, thickish, whitish yellow
(somewhat olive when dry). The rudi-
ments of the peridioles spring out as papilla
from the branches, becoming pear-shaped ;
and when two come into contact, they cohere,
and become confluent into a fusiform body.
The contents of the filaments next ascend
and accumulate in the peridiole, at length
forming a black globule (sporange?). While
this is ripening, the apices grow out into
long simple filaments.

Fig. 716.

Syzygites megalocarpus.

A branched filament, exhibiting the conjugation in

various stages.
Magnified 200 diameters.

BIBL. Ehrenb. Verhandl. Naturf. Freund.
Berlin, i. p. 91 ; Fries, Syst. Myc. iii. p. 329 ;
Berkeley, Ann. Nat. Hist. i. p. 259; Van
Tiegh. Ann. d. Set. Nat. 1873.

T.

TABELLARIA, Ehr.— A genus of Dia-
tomaceae.

Char. Frustules tabular, attached, at first
united into a filament, subsequently cohe-
ring only by the angles, with longitudinal
yittae interrupted in the middle; valves
inflated in the middle and at each end,
striated; freshwater.

T. flocculosa (PL 17. fig. 27 a, 6). Septa
3-5 on each margin. Length 1-960 to
1-840".

T. fenestrata. Frustules oblong; vittee
two, opposite. Length 1-600 to 1-290".

TACHIDIUS.

[ 750 ]

Five fossil species.

BIBL. Kiitz. Sp. Alg. 118; Smith, Br.
JDiat. ii. 44; Pritchard, In/us. 807.

TACHID'IUS, LiUj.— A genus of Cope-
podous Entomostraca. T. brevicornis ; ma-
rine. (Brady, Copep. ii. 19.)

TACHYGO'NIUM, Nag.— A doubtful
genus of Palmellaceee. (Rabenh. Alg. iii.
36.)

TADPOLE. See FROG.

TJ2NIA (Tape-worm).— A genus of Ces-
toid Entozoa.

Char. Body elongate, compressed, jointed.
Head mostly broader than the very narrow
neck, with 'four suctorial depressions ; and
usually a median, imperforate retractile
rostelluni, very frequently armed with one
or two circles of minute recurved hooks,
especially in the young state. Genital ori-
fices situated at the margins of the joints or
proglottides, either on one side only, or on
both margins and on alternate joints.

The TcenicBj of which the common tape-
worm may be taken as the type, are found
in vertebrate animals alone, and in these
only in the alimentary canal. They are
most common in birds, next in mammalia,
then in fishes, and lastly in reptiles.

The species are very numerous : Rudolphi
enumerated 146 ; Dujardin 135.

Tcenia solium,ihQ common human English
species, varies in breadth from 1-50 to 1-40"
at the anterior part, to about 1-3" at the
middle and posterior part. At the anterior
extremity is situated a central rostelluni,
which is surrounded by a crown of small
recurved hooks, as in PL 21. figs. 1 / & 10.
Behind these are four suctorial depressions,
which are not pervious at the bottom. The
digestive system is ^wanting, and the worm
absorbs by its surface; but according to
Blanchard, it is represented by two tubes or
lateral canals (PI. 21. fig. 14 a), having be-
tween them a transverse canal at the sum-
mit of each joint; these extend from the
anterior to the posterior end of the body.
In the cephalic portion, directly behind the
suckers, there is a kind of lacuna or furrow
communicating directly with these intesti-
nal tubes ; and it appears that the nutritive
matters respired by means of the suckers
penetrate into this lacuna, and thence into
the digestive canals. These tubes have di-
stinct walls, and are best seen when the animal
has been macerated in water, and is exami-
ned by transmitted light, or after having
been injected. But this is very doubtful.

The 'vascular system, according to the

above author, consists of four longitudinal
vessels (PI. 21. fig. 14 V) situated a little
above the intestinal tubes, and infinitely
more slender. They traverse the whole
length of the body; and between them
are numerous transverse vessels (PI. 21.
fig. 14). These so-called digestive and vas-
cular canals are now considered as belonging
to a water-vessel system ; the canals unite
in the last segment in a receptacle.

The male generative organ consists of a
slender coiled tube, extending to near the
principal ovigerous canal, where it is pre-
ceded by some very small testicular capsules
(PI. 21. fig. 14 c). The slender tube termi-
nates in a duct (fig. 14 d), which opens into
the lateral orifice, or sometimes it projects
externally in the form of a spiculum. The
ovary consists of a principal median canal,
presenting slight flexuosities, and extending
nearly from one end to the other of each
joint. It presents C86cal branches on both
sides, and opens by a slender oviduct (fig.
14 e) just within the genital orifice.

The ova are innumerable ; one is figured
in PI. 21. fig. 15. They consist of an outer
delicate membrane, enclosing a gelatinous
substance containing numerous highly re-
fractive globules. Within this is another
very delicate and transparent membrane,
closely applied upon a brittle, dark-looking
(by transmitted light, but white by reflected
light), thick envelope, within which is the
yolk or embryo, according to the state of
development of the ovum. Very frequently
the hooks of the young tsenia are seen im-
bedded in its centre, as shown in the figure.
The thick brittle coat of the ovum exhibits
an appearance of radiating fibres (canals ?) ;
and when broken, the fractures are radiant.
When the middle of the outer surface of
the brittle envelope is brought into focus, it
presents a tolerably regular appearance, as
if composed of cells; this arises, however,
from the extremities of the fibres being
brought into focus.

The filiform spermatozoa are readily found,
simply by picking any joint containing ova
to pieces with needles.

The young animal, consisting of head and
neck only, was formerly considered distinct,
and placed in a genus (Scolex).

Among other species may be mentioned :
Tccnia mediocanellata, the unarmed tape-
worm of the ox ; T. crassicollis, in the cat ;
T. echinococcus, in the dog and wolf ; T.
serra'a, in the dog ; and T. nana, human, in
Egypt.

T.EXITIS.

[ 751 ]

TARGIONIA.

The old genera Cccnurus, Cysticercus, and
EC/H'HOCOCCUS are the larval or nurse-forms
of Tcenia.

BIBL. Weinland, on Tape-worms ; Som-
mer, Geschlechtsory. v. T. sol. fy mediocanel- \
lut a ; Mejrnin, Compt. rend. 1870, 88, Ann.
X. 11. 1870, iii. 317; Piutner, Bau fyr.
1880; Moiiiez, Cestodes, 1881; Stein, Ent-
icick. n. Parasitism, menschl. Cestoden, 1882.

TyENITIS,Sw.— A genus of Gramniitidese
(Polypodiaceous Ferns). Five species; tro-
pical". (Hooker, Syn. 300.)

TALC. See MICA.

TAO'NIA, J. Ag.— A genus of Dictyo-
taci'se (Algie), containing one rare British
species, T. a/omaria, which has a flat, mem-
branous, fan-shaped, deeply cleft frond,
3 to 12" high, of brownish olive colour;
marked on both faces, at intervals of 1-4 to
1-2", with concentric wavy lines, formed by
rather crowded dark-brown lt spores," the
interspaces being dotted over with scattered
spores. The disk of attachment is covered
with woolly filaments.

BIBL. Harvey, Mar. Alg. 38; Thuret,
Ann. Sc. X. 4. iii. 7.

TAPIIPJ'NA.— A very low form of As-
coinycetous Fungi, formerly included under
EUINKUM, to which genus E. aureum, on
Poplar, and E. clandestinum, on Hawthorn,
are now referable. (Tulasne, Ann. d. Sc.
N. ser. v. ; Greville, Crypt. Fl.}

TAPHROCAM'PA, Gosse.— A genus of
llotatoria, of the family HydatiiiEea.

Char. Rotatory organs absent ; body fusi-
form, annulose, tail forked, gizzard oval.

T.anmdosa. Freshwater; length 1-110".

BIBL. Gosse, Ann. N. R. 1851, viii. 100;
Pritchard, Inf. 002.

TAPIOCA. — A very pure fecula prepared
from the liner particles of the starch of the
Mandioc or Cassava plant (PI. 40. fig. 14).
The starch-granules of tapioca of the shops
appear to have undergone the action of
heat, which disguises the characters. See
STARCH.

TAHDIG'RADA (Water-bears).— An
Order of Arachnida.

These microscopic animals are found in
stagnant fresh water, amongst water-plants,
in patches of wet moss, in the gutters of
houses, &c.

Body soft, cylindrical or elongate -oval in
outline, with four transverse furrows or in-
distinct segments, and a fifth anterior, cor-
responding to a head, short, conical, retrac-
tile and with indications of two or three
segments ; some times dilated at the end to

form a sucker, or furnished with unequal,
short, palp-like processes. Eyes two.

The oral organs are represented by a tu-
bular rostrum, through the sides of which,
from without inwards, two calcareous styles
or mandibles pass, and serve to wound the
animals forming their prey. At the base
of the rostrum is a gizzard with radiating
muscular fibres, in Macrobiotus enclosing a
kind of framework consisting of six parallel
jointed cylinders.

The alimentary canal is straight, and fur-
nished with lateral csecal appendages. The
ovary is a simple sac, behind which is
situated a seminal vesicle containing sper-
matozoa, both opening into a cloaca. But
few eggs are produced at a time ; they are
either smooth, rugose, or studded with
points, and are usually deposited during the
ecdysis, the exuviae serving as a protection
to them, during the process of hatching.
The young resemble the parents.

The Tardigrada resemble some of the
Ptotatoria in reviving after having been kept
dried for years.

Genera : Emydium, Macrobiotics, Milne-
sium (Arctiscon, doubtful).

BIBL. Doyere, Ann. Sc. Nat. 2. xiv. 209,
xvii. 103, xviii. 1; Dujardin, x. 185; Vogt,
Zool. Brief e, i. 400 ; Kauffmann, Sieb. uud
Kott. Zeitschr. iii. 220; Greef, Schultzes
Archiv, i. 101 ; Lubbock, Metam. of Insects.

TARGIO'NIA, Mich.— A genus of Pel-
liese (Hepaticas), characterized by the almost
sessile globose capsule arising from the end
of the midrib of the under face of the frond,
which is somewhat fleshy, smooth, deep-
green, purplish at the edges, and forms large
patches on rather moist but exposed banks.
The frond has an epidermis on both faces,
with stomata and intermediate parenchyma ;
the midrib is only apparent beneath, and
has radical hairs, with purple scales. The
perichaete originates from this rib, on the
under surface, rising to the upper side (fig.
717). When mature, it is globose, of dark
purplish colour and firm texture, and marked
with a vertical prominent line or keel : at
this line it ultimately splits into two valves
(fig. 718). Hofineister's observations, how-
ever, show that this envelope grows up
after the fertilization of the archegone,
which is originally naked in its upper half ;
hence it would seem to be a perigone.
Several archegones are found half-immersed
in the end of the midrib ; and one of these
is converted into a fruit ; the lower part be-
comes spherical, and the neck forms for a

TABGIONIA.

C 752 ]

TEA.

Fig. 717.

Fig. 718.

Targionia hypophylla.

Pig. 717. Lobe of a frond with fruit. Magnified 5
diameters.

Fig. 718. Perichsete opened, showing the globular
sporange. Magnified 20 diameters.

Fig. 719. Vertical section of a very young sporange.
Magnified 200 diameters.

Fig. 720. A branched elater. Magnified 200 diameters.

Fig. 721.

Fig. 722.

Figs. 721 & 722. Groups of four spores, not quite ma-
ture. Magnified 400 diameters.

Fig. 723. Parent cells of spores and imperfect elaters,
from a more advanced fruit. Magnified 100 diameters.

Fig. 724. The same. Magnified 200 diameters.

Fig. 725. A single ripe spore. Magnified 400 dia-
meters.

long time a filiform point or style. This
epigone bursts irregularly and vertically.
The spherical capsule emerges from it, but
is not protruded beyond the perichsete. The
globular capsule bursts irregularly at the
summit, and discharges spores and elaters
resembling those of Marchantia (figs. 723
to 725). The antheridia are imbedded in the
midrib, opening on papillse on the lower face.

BIBL. Hook. Brit. Flor. ii. pt. 2. p. 105 j
Corda, Sturm's Deutschl, Fl. Jungerm. pi.
26 ; Nees, Lebermoose, iv.

TARTARIC ACID.— The crystals of
this substance, which belong to the oblique-
prismatic system, exhibit beautiful colours
under the polariscope. A concentrated
aqueous solution is useful in the chloride-
of-gold staining process.

TAYLO'RIA, Hk.— A genus of Splach-
naceae (Acrocarpous Mosses). T. serrata
(fig. 474, p. 512), on Scotch mountains.
(Wilson, Bry. Brit. 283.)

TAXUS, L. — Taxus baccata is the Yew
tree, belonging to the Coniferee. Its wood
(PI. 48. fig. 4), as also that of T. canadensis,
shows the remarkable combination of spiral
fibres with the coniferous pits. Its embryo-
logy is also interesting. See CONIFEBJE
and OVULE.

TEA (the prepared leaves of Thea viridis
and T. Bohea, Nat. Ord. Ternstrceiniaceae).
— This important article of commerce has
afforded some of the most remarkable ex-
amples of systematic fraud, practised not
merely by the vendors in this country,
but by the Chinese manufacturers. The
principal adulterations of tea consist of re-
manufactured exhausted tea-leaves, spurious
tea made up of the dust of tea and other
leaves, together with earthy matter, by the
aid of gum, and of spurious tea made of
leaves of other plants, — the whole of these
being prepared either for black or green tea
by ( facing/ or imparting a colour or bloom
with black-lead, indigo, prussian blue, mica,
turmeric, &c.

The leaves of tea may be distinguished
when moistened and spread out, and still
more decidedly, even in fragments, by the
aid of the microscope, which shows the
peculiarities of the epidermis of the upper
or lower faces, &c. (PI. 2. fig. 1). Other
leaves fraudulently introduced may be thus
separated, and often identified by careful
comparison with known kinds likely to
have been employed. The spurious tea
made up of agglutinated rubbish falls to
pieces instead of unrolling when infused

TEETH.

[ 753 ]

TEETH.

with hot water. The 'facing' of the various
kinds is mostly distinguishable with a com-
mon lens, and when the tea is infused forms
a sedimeut, the characters of which may be
determined by the microscope and by che-
mical analysis.

BIBL. Hassall,Foorf#c.,268; Warington,
Tr. Chem. Soc. 1851.

TEETH.— The teeth of the Mammalia
are inserted in sockets or alveolar cavities
of the jaws.

The teeth consist of: — a crown, or that
portion which projects beyond the alveolar
cavity and the gum ; the fangs, or the por-
tions which are inserted into the bony
structures ; and a neck, or narrower inter-
mediate portion. The crown of the tooth
contains the pulp-cavity, which is closed
above, but prolonged below through the
fangs.

In regard to their structure, teeth are in
part identical with bone, in part closely
allied to it ; but in respect to their develop-
ment, they must be regarded as formations of
the mucous membrane, as modified papillae.

The substance of human teeth consists of
three parts : — the ivory or dentine (fig. 726 d),

Fig. 726.

Molar tooth, human : longitudinal section.

a, enamel; 6, pulp-cavity ; c, cement; d, ivory, with
the ivory-tubes. Magnified 5 diameters.

which constitutes the greater portion of
their mass, and to which their form is

mainly owing ; the cement, or bony portion
(fig. 726 c), which forms an external cover-
ing, principally of the fangs ; and the ena-
mel ( fig. 726 a), which covers the crown.

The ivory or dentine (figs. 726 d, 727 d) is
whitish and of a silky lustre, and, excepting
a small portion at the base of the fangs,
forms the entire boundary of the cavity of
the teeth. It consists of a homogeneous

Fig. 727.

Transverse section of the same; the references as above.
Magnified 5 diameters.

matrix enveloping numerous tubes or cana-
liculi, called the ivory-tubes (fig. 729 a, b).
The tubes are very fine, and pursue an un-
dulating course, at first curving, then bifur-
cating, throughout giving off numerous fine
lateral communicating branches, which are
best seen in a horizontal section (fig. 728),
and ultimately ramifying and anastomosing
freely. They commence at the surface of
the pulp-cavity, in the crown following a
somewhat radiating direction from its centre
(fig. 726), whilst in the fangs their course
is more horizontal. They have distinct

Fig. 728.

Transverse section of the ivory-tubes of the fang (a),
fig. 729), showing their numerous anastomose*.
Magnified 450 diameters.

walls, about equal in thickness to their
calibre, although in transverse sections (tig.
730) this thickness is generally exaggerated,
on account of their being obliquely divided.
They contain air in tl e dry state, which

3c

TEETH.

[ 754 ]

TEETH.

may be displaced by liquids. By removing
the inorganic salts from a tooth with dilute

Fig. 729.

Ivory-tubes of a fane of a human tooth, a, inner
surface of the ivory, with few tubes ; b, their branches ;
c, their terminations in loops ; d, granular layer, con-
sisting of small ivorv globules at the boundary of the
ivory; e, lacunae of bone, one anastomosing with an
ivory-tube. Magnified 50 diameters.

muriatic acid, and macerating the remaining
cartilage with acids or caustic alkalies until
it forms a pasty mass, the tubes may be
isolated from the basis.

Fig. 730.

Transverse section of the ivory-tubes, a, closely
aggregated ; 6, wider apart. Magnified 450 diameters.

In sections made from fresh teeth, high
powers of the microscope (500 or 1000
diameters) being used, it is not difficult to
recognize, especially in the centre of the

Fig. 731.

Perpendicular section of the apex of a human incisor
tooth, a, pulp-cavity ; 6, ivory; c, curved contour lines
with interglobular spaces ; d, cement ; e, enamel, with
indications of the course of the fibres in various direc-
tions ; f, coloured stripes of the enamel.
Magnified 7 diameters.

TEETH.

TEETH.

tooth, the fine, pale, homogeneous processes
of the tooth-pulp or dentine-fibres. These
may he stained by carmine.

the ivory not unfrequently exhibits indi-
cations of a laminated structure, forming,

Fig. 732.

Portion of the ivory, with ivory-globules and inter-
globular spaces filled with air. Magnified 350 diams.

in longitudinal sections, curved lines more
or less parallel to the outline of the crown
(fig. 731), appearing as rings in transverse
sections, and called the contour-lines.

Fig. 733.

Ccmei t and ivory of the fang of a tooth of an old
person, a, cavity ; b, ivory ; c, cement with lacunae ;
e, Haversian canals. Magnified 30 diameters.

Near the enamel (fig. 731) and the cement
(fig. 7i)9 d) also, the ivory presents one or
more irregular dark patches or bands, often
continuous with the ends of the contour-

lines, and exhibiting a coarsely cellular
appearance. On careful examination, the
dark appearance is seen to result from a
number of irregular spaces filled with air
(fig. 732 a) intervening between certain
globules, called ivory-ylobules, the spaces
being termed the interglobular spaces. In
the recent tooth, these spaces are tilled with
the organic basis of the ivory, containing
tubes like the rest of that substance, in which,
however, the inorganic matter has not been
deposited ; hence this structure arises from
imperfect development.

Other, ill-defined iridescent stripes, run-
ning parallel to the pulp-cavity, are some-
times seen; these correspond to the primary
curves of the ivory-tubes.

The cement or bone of teeth forms the
outer coating of the fangs (figs. 726 & 733, c),

Fig. 734.

Enamel-flbrep, isolated by the very slight action of
muriatic acid ; human. Magnified 30 diameters.

sometimes cementing them together. It
commences as a very thin layer at the part
where the enamel ceases, increasing in
thickness towards the ends of the fangs.
The cement does not differ from bone in
structure, except in rarely containing Ha-
versian canals. In the molar teeth of old
persons, however, these are met with
(fig. 733 e). The lacunae are frequently
absent from the thinner portion of the ce-
ment ; and it sometimes contains tubes like
those of the ivory. The interlacunar sub-
stance is sometimes striated, and exhibits a
laminated structure.

The enamel (fig. 72G a) covers the ivory
3c2

TEETH.

[ 756 ]

TEETH.

of the crown of the teeth. It is thickest at
the opposing surface, decreasing towards
the neck, where it terminates. The cuticula
is an extremely resistant investment to the
exposed portions of the teeth, and which
disappears when they are mature. It is
separable after the action of muriatic acid,
and may be tinted with a solution of nitrate
of silver, which causes the appearance of
figures like large epithelial cells. The
enamel has a fibrous aspect, and appears of
a bluish-white colour by reflected light,
and of a greyish brown by transmitted

Fig. 735.

light. It is very brittle, and so hard as to
strike fire with steel. It consists of nume-
rous solid fibres or prisms (fig. 734), about
1-6000 to 1-5000" in breadth, mostly six-
sided, more or less wavy, slightly varicose,
and transversely striped. These usually
extend throughout the thickness of the
enamel, and are placed in a direction gene-
rally perpendicular to the surface of the
portions of the ivory which they cover
(figs. 726, 731). The form of the fibres is
best seen by viewing their ends in a trans-
verse section (fig. 735). The prisms do not

Fig. 736.

Pig. 735. Surface of the enamel, with the ends of the enamel-fibres, from the tooth of a calf. Magnified 350
diameters.

Fig. 736. Diagram showing the development of a milk-tooth, and the corresponding permanent tooth, a, furrow ;
b, the same with the papilla ; c, the same closing, with the commencement of the reserve cavity ; d, the same, further
closing; e, follicle completely formed, with the reserve cavity; /,the reserve cavity receding; g, the same, with a
tooth-germ; A, the alveoli of both capsules formed, the milk-tooth being through the gum; i, the same further
advanced, the neck of the capsule forming a solid cord.

run exactly parallel with each other, but
are arranged in groups or zones, the fibres
of which cross each other. The fibres
are readily isolated before they have be-
come so developed as to be hard, and when
very slightly acted upon by muriatic acid.
It is doubtful if sometimes 'the ivory-tubes
extend into the enamel.

Two kinds of dark bands or stripes are
seen traversing the enamel (fig. 731). The
direction of one of these coincides pretty
nearly with that of the fibres, and it arises
from the crossing of the zones of fibres,
allowing more or less light to pass through,
the bands being light and dark. The other
set (fig. 731, ff) consists of arched, brownish
stripes, indicating the laminated structure

of the enamel. Under the polariscope, a
third set becomes visible, arising from the
variable inclination of the axes of the fibres
to the plane of polarization.

The enamel is often traversed by cracks,
mostly running parallel with the fibres, and
containing air in dry teeth.

Pulp. — The pulp of the teeth is the vas-
cular and nervous matrix of the dentine
and the remains of the original tooth-papilla.
It contains a few blood-vessels and nerves,
being connected with the periosteum and
base of the sockets of the jaw. The princi-
pal part is made of indistinctly fibrous con-
nective tissue, containing numerous cells;
and it appears to be quite cavernous frcm
the breaking up of the terminal capillaries.

TEETH.

[ 757 ]

TEETH.

The external layer is formed of large cells of
el( nitrated form, provided with numerous
processes called odontoblasts, which are
arranged so as to form a kind of columnar
epithelium. They are finely granular, but
have no cell-wall. Three kinds of pro-
cesses may be distinguished in these cells —
the dentinal, pulp, and lateral processes.
The dentinal processes become the before-
mentioned dentinal fibres of the ivory.

Chemically, teeth consist of an organic,
cartilaginous basis, agreeing in composition
with that of bone, and of inorganic matter,
consisting principally of phosphate of lime
with a sm ill quantity of the carbonate.

Dcirlopmcnt. — At the beginning of the
third mouth, the margins of the jaw form a
slight ridge, which consists of a thickening
of the embryonic connective tissue and
epithelium of 'the mucous membrane of the
mouth. The rudiments or germs of the first
(milk) teeth are met with in the sixth week
of foetal life, and consist of small papillfe,
one for each tooth, which become visible in
grooves of the mouth, afterwards forming

Fig. 737.

Lower jaw of a human nine weeks' foetus, a, tongue,
turned hack ; 6, right half of the lower lip turned aside ;
fc', left half of the lip cut off: c, outer wall of the gum ;
d, inner wall of the gum ; e,f, g,h, papillae of the teeth ;
^, fold where the sublingual duct subsequently opens.
Magnified 9 diameters.

the alveolar processes. The epithelium
forms the enamel, and the other tissue the
dentine and cement. Processes from the
sides of these dental grooves are then
formed, and, approaching each other, en-
close the papilla in distinct follicles, the
margins of which gradually grow over the
papillae, and uniting, convert them into

| closed sacs or capsules. The pulps then be-
come moulded into the form of the future
teeth, the bases of the pulps dividing into
as many portions as the teeth have fangs;
and as the capsules increase at this stage
faster than the pulp-s, a space is left be-
tween them, in which a gelatinous-looking
substance is deposited from the wall of the
capsule forming the enamel-organ. By
some recent authors, however, the existence
of the dental grooves is denied.

The capsule (fig. 738 a) possesses a con-
nective coat with vessels and nerves; and
from its base arises the tooth-germ or pulp
(fig. 738 h). The pulp consists of an outer

Capsule of the second incisor tooth of an eight months'
human foetus, a, capsule; b, enamel-pulp; c, enamel-
membrane: d, enamel; f, ivory-cells; h, papilla of
tooth or pulp ; t, free margin of enamel-organ.

Magnified 30 diameters.

non-vascular layer of elongated nucleated
cells, with filiform processes, in close appo-
sition (fig. 739 a), covering the surface of
the pulp — the ivory-membrane (fig. 738 /"),
not distinctly defined internally, but gradu-
ally passing into the vascular parenchyma
of the pulp. The inner part of the pulp
consists of indistinctly fibrous connective
tissue with nuclei, the vessels terminating
in loops beneath the enamel-membrane
(tig. 739 c).

The enamel-organ (fig. 738 b) covers by
its inner concave surface the pulp, its out-

TEETH.

[ 758 ]

TEGEOCKANUS.

side being in apposition with the capsule.
It forms a spongy tissue, composed of ana-
stomosing stellate cells or reticular areolar
tissue; in its inside is the enamel-mem-
brane, consisting of cylindrical epithelium
(fig. 738 c).

The enamel is formed by the direct cal-

Fig. 739.

Surface of the pulp of a newly-born infant, a, ivory-
cells ; b, their appendages ; c, vascular part of the pulp.

Magnified 300 diameters.

cification of the epithelium, the prisms re-
sulting from the calcification of the long
cylindrical cells.

Ossification commences by the deposition
of calcareous matter in the cells of the ivory-
membrane at the summit of the pulp ; this
is soon followed by similar deposition in the
cells of the enamel-membrane. By the fur-
ther formation of new cells and fresh depo-
sition, the structure of the teeth becomes
more and more consolidated, the spongy
tissue of the enamel gradually being ab-
sorbed.

When the entire enamel and a consider-
able portion of the ivory have been formed
in the capsules, these become too small to
contain the teeth, which then rupture them,
and continue to grow at the root, until the
crown projects above the margin of the jaw.
The remainder of the capsule then forms
the periosteum of the alveoli, and, by depo-
sition from the side next the tooth, pro-
duces the cement.

The permanent teeth are formed upon
the same plan : — the three last molars in
the remains of the primitive dental groove ;
the others in distinct sacs, called reserve

sacs, and formed in the wall of the follicles
of the milk-teeth.

The teeth of animals present numerous
interesting varieties, to which we can but
briefly refer. Thus, in the Mammalia the
enamel is often absent, the cement fre-
quently extends over the crown, the three
component structures are folded, the teeth
are compound, the ivory contains Haver-
sian canals, and the ivory-tubes enter the
enamel. In Reptiles the teeth are often an-
chylosed to the jaws. In Fishes the teeth
are often solid ; the ivory is furnished with
Haversian canals, sometimes isolated, and
each surrounded by a layer of ivory and ce-
ment, so that the teeth appear to consist of
aggregations of little teeth; the vessels
often branch and anastomose freely ; the
ivory-tubes are often very large or absent,
the ivory then consisting of a finely granu-
lar base with numerous vascular canals, true
enamel appearing to be absent.

The oral and gastric teeth of the Mol-
lusca (see TONGUE), Vermes, and Arthro-
poda, are composed of chitine, which is some-
times impregnated with lime or silica. The
teeth of Echinida are composed essentially
of thin leaflets aggregated into a radial
lamina ; and they are composed of elongated
prisms of carbonate of lime, somewhat
curved at their extremities. These lustrous
calcareous plates lie between the prisms, and
present a fine plexus of anastomosing cana-
liculi.

It may be said generally that the teeth
of the higher Invertebrate are to be re-
garded as epithelial structures, and that in
the lowest Vertebrata they are chiefly com-
posed of peculiarly modified and ossified
connective tissue.

The method of making sections of teeth
is described under PBEPABATION. They
should be very thin, and preserved in the
dry state.

BIBL. Owen, Odontography, and TodcVs
Cycl, iv. 864 ; Goodsir, Ed. Med. and Sure/. Jn.
1839, i. ; Tomes, Dental Surgery, and Phil.
Tr. 1849, 1850; Hanover, Verh. Leopold.
Carol. Ak. xxv. 2, Mic. Jn. 1857, v. 166;
Huxley, Qu. Mic. Jn. 1854, 1855, 1857;
Lankester, Qu. Mic. Jn. 1867 ; Boll, Zalin-
pulpa, Arch. Mik. An. iv. 1868 ; Cutler, Den-
tal Comos, 1867; Bolleston, Qu. Mic. Jn.
1872; Waldeyer, Strieker s Hum. fy Comp.
Hist, i.; White, Mn. Mic. Jn. vii. 263;
Tomes, M. M. Jn. xiii. 85 ; Frey, Hist, and
the lit.

TEGEOC'RAKUS, Mich.— A new genus

TELOTROCHIDIUM. [ 759 ]

TEST-OBJECTS.

of Oribatea (Michael, Jn. Mic. Soc. 1879,
247: 1880,32, 177).

TELOTROCIIID'IUM, Kt.— A genus of
Peritrickous Infusoria. Five, ovate or cam-
panulate, no tail ; two ciliary rings ; anal
aperture posterior.

T. crateriforme ; freshwater. (Kent, Inf.
843.)

TEM'ORA, Baird.— A genus of Copepo-
dous Eutomostraca, family Diaptomidse.

Char. Thorax composed of five, abdomen
of three j oints ; lesser antennae two-branched ;
first four pairs of logs each giving off a two-
jointed branch. T. finmarchica. On the
British coasts. (Baird, Br. Entomostr. 227 j
Brady, Cop. i. 37.)

TENDON. See LIGAMENTS.

TEXTHKE'DO, Leach.— A genus of Hy-
menopterous Insects, of the family Tenthre-
diuidne (Saw-flies).

The species of Tcnthredo and of the other
genera belonging to the family, both of
which are very numerous, are interesting on
account of the remarkable structure of the
ovipositor, which consists of two flattened
and curved saw-like plates. These are used
to saw the leaves of plants, for the deposi-
tion of the eggs.

The insects are found upon gooseberry-
bushes, rose-bushes, the white thorn, the
willow, alder, poplar, the plum- and other
fruit-trees, cabbage, turnip, bramble, &c.
The larvae are very destructive to agricul-
tural crops.

T. nassata is represented in figure 366
(P- 437).

BIBL. Westwood, Introduction, ii. 90.

TEREBEL'LA.— A genus of Tubicolar
Annulata.

The animal forms a tube of sand and por-
tions of shell, agglutinated by a secretion.
Carpenter remarks that in the respiratory
organs situated in the part outside the tube
— the head — two liquids may be seen circu-
lating:— one colourless, containing numerous
cell-like corpuscles, which can be seen in
the smaller and more transparent species to
occupy the space intervening between the
outer surface of the alimentary canal and
the inner wall of the body, and to pass
from this into canals, which often ramify
extensively in the respiratory organs, but
are never furnished with a returning series
of passages ; while the second is a usually
red liquid containing few particles, and en-
closed, in a system of proper vessels commu-
nicating with a central propelling organ. In
Terebella a distinct provision is made for the

aeration of both fluids ; for the first is trans-
mitted to the tendril-like tentacula which
surround the mouth, whilst the second cir-
culates through the beautiful arborescent
branchiae situated just behind the head.
The former are covered with cilia, the action
of which continually renews the water in
contact with them, whilst the latter are
destitute of them. The colourless liquid
is probably blood, and the red belongs to the
water-system.

BIBL. Huxley, Comp. An.} Carpenter,
Microscope.

TERPSIN'OE, Ehr — A genus of Diato-
macese.

Char. Frustules tabular, obsoletely
stalked, subsequently connected by isthmi,
and with transverse, short, interrupted,
capitate vittae; valves in side view with
lateral inflations.

T. musica (PI. 19. fig. 33, side view; PL 25.
fig. 10, front view). Frustules very faintly
punctate, in front view rectangular oblong ;
side view equally inflated in the middle and
at the ends, in older specimens constricted
in the middle, inflated beyond the middle
towards both ends, the apices produced and
obtuse, the nodules separated by septa.
Length 1-180".

T. indica (Anaulus ind., E.).

BIBL. Ehr. Abh. Bed. Ak. 1841, 402;
Kiitz. Batill. 128 ; So. Ala. 119 ; Pritchard,
Inf. 850.

TESSEL'LA, Ehr.— A genus of Diato-
maceaa.

Char. Frustules broadly tabular, not con-
catenate, with crowded, longitudinal, alter-
nate vittae, interrupted in the middle; stipes
absent (?). Marine.

T. interrupta (PL 19. fig. 35). Length of
frustules 1-580; breadth 1-560 to 1-120".
Found with Striatella.

BIBL. Ehr. Inf. 202; Kiitz. Bacill. 125;
Sp. Alg. 114; Pritchard, Inf. 804.

TESTAMCEBIFOR'MIA, Carter.— Pa-
rasitic, lobular, and wild-growing Forami-
nifera, some nearly \ inch long. Holodad-
nia and Cysteodictynia with calcareous,
Ceratestina with chitinous test. Gulf of
Manaar. (H. C. Carter, Ann. N. H. June
1880, 446.)

TEST - OBJECTS. — Test-objects are
microscopic objects used to determine the
value of object-glasses.

We must presume that the reader has
perused the remarks upon object-glasses in
the INTRODUCTION (p. xvi), also the article
ANGULAR APERTURE; otherwise the

TEST-OBJECTS.

[ 760 ]

TEST-OBJECTS.

observations made here will be unintel-
ligible.

The main points in which object-glasses
differ from each other are four : viz. their
magnifying power; their defining power;
their penetrating power ; and their correc-
tive adaptations.

The magnifying or separating power
scarcely requires notice ; it must be adapted
to the size of the objects likely to come
under examination. Usually, several object-
glasses are kept, of different powers ; at all
events, if scientific investigations are to be
pursued, a power of 400 diameters must be
accessible, and this without the use of the
highest eyepiece. The magnifying power
should be ascertained by MEASUREMENT,
and not by j udging from the focal length.

Good defining power is the most im-
portant character of an object-glass ; and if
good in respect to this, the dark boundary
lines of the test-objects will appear clear,
black, sharp, as if engraved, and quite free
from colour. If this is ascertained to be
the case, the higher eyepieces should be
put on ; and it must be observed that
although the sharpness of the outline is
somewhat diminished, all the parts are
clearly distinguishable as before. In this
examination the light should be as direct
as possible.

The power of displaying the minute or
internal structural peculiarities of objects,
or the penetrating power, as it is called, de-
pends upon two distinct circumstances — the
goodness of the defining power, and the
magnitude of the angular aperture of the
object-glass: the degree of obliquity of the
light is also of great importance in con-
nexion with the latter.

Thus, in examining the scale of a Podura
(PL 1. fig. 12 a, b, c), the magnifying power
being sufficiently high, if the defining power
be good, the wedge-shaped bodies will be
clearly and sharply displayed by direct light,
and whether the angular aperture be large
or small. But if we examine a valve of
Pkurosigma (PI. 1. tigs. 17 & 18) by direct
light, the minute structure will be invisible,
however small or large the angular aperture
may be, or however perfect the defining
power ; but if the light be thrown obliquely,
and the aperture be sufficient, the striae will
at once become evident. Thus there are
two distinct kinds of penetrating power,
one of which is the same as the defining
power, the other depending upon a different
cause j hence the term penetration or pene-

trating power should be laid aside, as
tending to cause confusion, the properties
of object-glasses being reducible simply
to their defining power and their angular
aperture.

In recent times, a new meaning has been
assigned to the term penetrating power,
viz. that of rendering a certain thickness of
an object visible at one time. This de-
pends upon the suiallness of the angle of
aperture of the object-glass. It seeuis a
useless innovation.

The defining power should be tested upon
the different objects mentioned below in
connexion with each object-glass, and the
angular aperture should be determined by
measurement (ANGULAR APERTURE) ; for
judgment founded upon the examination of
the valves of the Diatomacese may be very
fallacious to an unpractised observer, on
account of the influence of the obliquity of
the light, and of the correcting adjustment.
If, however, an opinion is to ba formed in this
way, the valves should be examined by ob-
lique light thrown from all sides, as with
the central stop in the condenser, so that
the dots may be viewed; for an object-
glass may show the lines very fairly,' but
the dots very badly.

The correcting adjustment is of import-
ance in examining very delicate objects or
structures with the high powers ; it should
therefore always be present.

We sub join "a list of a few of the objects
which will be found most suitable for the
purpose of testing an object-glass.

1£ or 2-inch object-glass. Magnifying
power 20 diameters.

Test-objects: the pygidium of the flea
(PI. 1. fig. 13 a), in which the general out-
line and the hairs should be distinct ; the
hair of the mouse (PI. 1. fig. 3). Also, as
an opaque object, a piece of an injected
preparation (PL 39. figs. 33-35).

\-inch or %rds object-glass. Magnifying
power 60 diameters.

Tests: hair of Dcrmestes (PI. 1. fig 1);
of the bat (fig. 2) ; of the mouse (fig. 3) ;
the pygidium of the flea, the outline of the
areolse being distinguishable under the high
eyepiece (120 to 200 diameters), but not
the rays. Also an injection, as a piece of
lung.

\-inch or fifths-inch object-glass. Magni-
fying power 100 to 120 diameters.

Tests : hairs (PL 1. figs. 1, 2, 3) ; the disks
of deal (fig. 4) j the coarser scales of Le-
pisma (fig. 6 a) ; the pygidium of the flea

TEST-OBJECTS.

[ 761 ]

TEST-OBJECTS.

(fig. 13 a, b), the entire structure visible
under the high eyepiece ; a dark scale of
Podura (PI. 1. fig. 12 A).

\-inch object-glass. Magnifying power
220 diameters.

Tests : hair of Dermestes ; the disks of
d"al ; the salivary corpuscles (PI. 1. fig. 5),
the moving molecules being clearly distin-
guishable ; the smaller scales of "Lepisma
(PI. 1. fig. 6 b, c) ; the scales of Podura :
the filaments of Didymohelix (fig. 10 «) ; the
pvgidium of the flea, and the scales of
PtotfM brassica (PI. 34. fig. 24).

fy.h-inch object-glass. Magnifying power
420 to 400 diameters

Tests: the paler scales of Podura; the
pvgidium of the flea ; the scales of Pontia
brd*xic<e ; the filaments of Didymohelix,
showing the component fibres ; the salivary
corpuscles.

i\th or jgth-inch object-glass. Magnify-
ing power (300 to 650 diameters.

Tests : the paler scales of Podura ; the fila-
ments of DidymoJielix mounted in balsam ;
and the primitive tibrillae of muscular fibre
(PL 22. fig. 366, d).

,'jtfA and upwards. Magnifying power
1260 to 2000 diameters.

Tests : the more delicate of the above
objects, and the finest Nobert's lines.

It will be observed that we have omitted
the tests for angular aperture, which are
often now regarded as the true tests of the
value of an object-glass. Those, however,
who wish for an interesting series of difficult
objects in this respect, may use that of
Dippel, viz. : the valves of Pleurosigma for-
mosum, attenuatum, angulatum ; Grammato-
phora marina ; Nitzschia sigmoidea ; Navi-
cufa rhomboides ; N. ajfinis, Amici's test-
object, that used at the Exhibition of 1862,
mounted in balsam, the transverse lines;
tSurireUa gemma, the longitudinal lines;
Grammatophora subtilissima ; Frmtulia
saxonica, and Bailey's Hyalodiscus subti-
lissimus. Nitzschia tania and Berkeley a fra-
f/i/is are also fine object1?. Holler's or
Rodig's Test-plates may also be used. These
consist of a series of the valves of Diatoma-
cene, arranged according to their difficulty,
and mounted on a glass plate in balsam.
We shall now offer a few
General remarks on the application of
test-objects to the choice of an object-glass.
A great difficulty presents itself in this ques-
tion in the case of persons commencing the
use of the microscope ; for on viewing
almost any object, they will see so much

that was invisible before, that they are natu-
rally led to regard an object-glass as good
which may simply possess tolerably magni-
fying power.

There is also some difficulty to an un-
practised eye in discriminating between a
well-detined margin of an object, and one
which is ill-defined. This may be overcome
by purchasing one or two test-objects from
those who mount objects for sale, and first
viewing them under their microscopes; or
by examining some of the objects exhibited
at the evening meetings of the learned
societies.

The objects themselves are also variable,
some being much more delicate than others
even of the same kind. Moreover objects
viewed under immersion-glasses are more
brilliant than under the dry object-glasses.

The manner in which objects are mounted
is also of importance; for if they be immersed
in too much balsam or covered by too thick
a cover, no object-glass will show them well,
however good it may be. Hence the ne-
cessity of purchasing the test-objects, in the
case of an inexperienced observer. Any of
these may be obtained from Norman, Foun-
tain Place, City Road; Wheeler, 48 Tol-
lington Road, Hollo way; Baker, 244 High
Holborn; of Smith and Beck, Ross, or
Powell ; or Bourgoyne, of Paris.

A few notes upon the test-objects them-
selves may not be out of place here.

Hairs of animals (PI. 1. tigs. 1-3). These
should be mounted in Canada balsam. Many
of those represented in PI. 29 might be used
with equal advantage.

Disks of deal (PI. 1. fig. 4), form a good
test-object on account of their freedom from
colour, whence the colours from uncor-
rected chromatic aberration are easily seen
with a bad object-glass.

Salivary globules (PI. 1. fig. 5 a, i, c). Ob-
tained from the saliva. A good test-object
for those engaged in physiological investi-
gations ; the marginal granules and the
moving molecules should be very distinct.

Scales of insects (PI. 1. figs. 6 a, b, c, 12 a,
b, c; PI. 34. fig. 24). These should be
mounted dry. The scales of Tinea and many
others have nothing to recommend them.
Nor do we advise the use of those scales
which exhibit the transverse striae by oblique
light, as those of Morpho (PI. 1. fig. 7), of
Hipparchia (fig. 9), &c., as they are easy
tests even to inferior English object-glasses
of the present day. The long scales of
Pontia brassicce, however, are good.

TEST-OBJECTS.

[ 762 ]

TETRANYCIIUS.

Didymohelix (PL 1. fig. 10 a, b, c, d).
The filaments should be mounted in solution
of chloride of calcium, or in Canada balsam.
It is very difficult to display the component
fibres of this beautiful object when in bal-
sam. It also forms a good test of magni-
fying power.

Didymoprium (PI. 1. fig. 11). The lon-
gitudinal lines upon the cells require con-
siderable magnifying power.

The pygidium of PULEX. An excellent
test-object, mounted in as small a quantity
of balsam as possible. Dujardin represents
the rays upon the disks as round, like so
many beads, whereas they are wedge-shaped
with the bases outwards.

The valves of the JDiatomacece. It is a
difficult matter to show the lines upon
Grammatophora marinawiih an object-glass
of 110° of angular aperture, requiring ex-
tremely oblique light ; but many of those
mentioned above are far more difficult.

The ultimate jibrillce of muscular fibre
(PI. 22. fig. 36). Mounted in liquid.
Kolliker represented them as beaded
(fig. 36 c) ; they have also been repre-
sented a.s in a : probably both these inac-
curacies arise from imperfect adjustment,
and from their immersion in too mnch
liquid. Their true structure is figured in
b, d, e.

Noberfs test-lines. See NOBEBT'S LINES.

We have omitted to notice several test-
objects, as the scales of some insects, a
minute globule of mercury, &c., because the
former have been so obscurely described
that we are unable to comprehend in what
the test-structure consists ; and the test-
appearances presented by the latter viewed
as an opaque object are inappreciable to one
unaccustomed to the use of the microscope,
by whom mainly are remarks upon test-
objects required. See on this matter,
Wenham, in Beale's How &c. p. 436.

Chevalier's test-object consists of the
scales of Pontia brassicce (PI. 34. fig. 24),
the granules being rendered distinct ; this
is a test for definition.

Mohl recommended the scales of Hip-
parchia janira for testing penetrating
power ; pollen-grains, the scaly elytra of the
diamond-beetle, or bat's hair, for definition.

Schacht's test-object consists of the scales
of Hipparchia janira (PI. 1. fig. 9c), a test
for moderate angular aperture and oblique
light.

BIBL. That of the INTRODUCTION, and
of ANGULAR APERTURE.

TE'THEA, Lam. — A genus of marine
Sponges.

Char. Solid and compact,rounded, covered
with a skin ; without sensible pores ; inte-
rior fleshy, with acicular and globulo-subu-
late spines (PI. 45. fig. e).

BIBL. Johnston, Br. Spong. 81; Gosse,
Mar. Zool. i. ; Huxley, Ann. N. H. 1851,
vii. 370.

TETMEM'ORUS, Ralfs.— A genus of
Desmidiacese.

Char. Cells single, simple, elongated,
straight, cylindrical or fusiform, constricted
in the middle ; segments emarginate at the
ends.

Sporangia square or round.

T. granulatus (PI. 14. figs. 33, 34) . Cells
fusiform both in front and side view, ends
colourless and lip-like j dots irregular.
Length 1-130".

T. Icevis (PL 14. fig. 35, in conjugation).
Cells in front view somewhat tapering, ends
truncate ; side view fusiform ; dots none, or
very indistinct (under ord. ilium. ). Length
1-860".

T. Brebissonii. Dots in longitudinal
rows.

BIBL. Ralfs, Br. Desmid. 145 ; Rabenht.
Alg. iii. 139.

TETR ACHASTRUM = Micrasterias pt.

TETRACY'CLUS, Ralfs.— A genus of
Diatomaceae.

Char. Frustules compound, aggregated
into a filament, in front view broadly tabular
with longitudinal interrupted vittae ; valves
inflated on each side in the middle.

Valves with coarse transverse striae.

T. Tkienemanni, Ehr. (lacustris, Ralfs)
(PL 17. fig. 28). Valves rounded or sub-
acute at ends, inflations rounded.

T. emarginatus. As the last, but valves
constricted towards the rounded and sub-
apiculate ends, and the inflations eniar-
ginate.

BIBL. Ralfs, Ann. N. H. 1843, xii. 105 •
Kutzing, Sp. Alg. 118; Smith, Br. Diat. ii.
37 ; Rabenht. Alg. i. 302.

TETRAGON'iCEPS,Brady.— A genus of
Copepodous Entomostraca. T. malleolata,
in dredgings. (Brady, Copep. ii. 65.)

TETRAMTTUS,Perty.— A genus of Fla-
gellate Infusoria. Free, changeable, tapering
behind, truncate in front; flagella four.
Three species ; in stale water and infusions.
(Perty, Lebensf. 170 ; Kent, Inf. 313.)

TETRAN'YCHUS, Duf.— A genus of
Tronibidina (Acarina). Spinning-mites.

TETRAPEDIA.

[ 763 ]

TEXTULAIUA.

Char. Palpi incumbent upon the rostrum,
stout, short, and conical; mandibles and
labium as in Ithajihignathus ; palpi chelate;
coxa- inserted in two groups on each side,
one for the two anterior, the other for the
two posterior; anterior legs longest, third
joint (femur) largest ; claws short and
greatly curved, and with rigid bulb-pointed
hairs.

Several species and varieties, red and
green.

T. telarius, the red spider. Yellowish ;
abdomen produced behind ; a dark yellow
spot on each side of the back. On ill-
conditioned greenhouse-plants, forming a
web.

T. glaber (PL 6. fig. 32). Very minute ;
eyes two, whitish, upon the anterior pro-
minence. Under stones in damp places.

T. lupidum (<.ri»tatu8, Duges) (PI. 6.
fig. 35). Legs slender, anterior very long ;
eyes three on each side ; several rows of
white points upon the back and margins of
the body. Under stones and upon plants.

Claparede places Trombidium autumnale
in this genus.

BIBL. Duges, Ann. Sc. N. 2. i. 24, & ii.
•V> : ( iervais, Walckenaer's Apteres, ii. 165 ;
Dufour, Ann. Sc. N. i. xxv. 279 ; Koch,
Deutschl. Cntstac. ; Boisduval, Ent. Hort.
88 ; Murray, EC. Ent. 97.

TETRAPE'DIA, Reinsch.— A genus of
Unicellular Algse.

Char. Cells compressed, quadrangular or
triangular, equilateral, becoming subdivided
into quadrate or connate segments or
rounded lobes, either by deep vertical or
oblique markings, or by wide angular or
rounded sinuses. (Archer, Qu. Mic. Jn.
1872, 351.)

TETRAP'LOA, Berk, and Br.— A genus
of Torulacei (Coniomycetous Fungi), com-
prising at present a single species, T. aris-
tata, a curious little fungus growing upon
leaves of grass. See TORULACEI.

TETRAP'LODON, Br. and Sch.— A ge-
nus of SplachnaceaB (Acrocarpous operculate
Mosses). T. mnioides and angustatus, on
dung in mountainous regions.

TETRASEL'MIS, Stein.— A genus of
Flagellate Infusoria. Free, obovate or
oblong; flagella four; protoplasm green,
with an eye-spot. T. cordiformis, fresh-
water. (Kent, Inf. 315.)

TETRAS'PORA, Link.— A gen us of Pal-
mellace8e(Confervoid Algae), nearly related
to the Ulvacese; indeed it is very difficult
to draw any very distinct line of demarcation

between Tetraspora and Monostroma, the
fronds of both of which are membranous
strata formed of a single layer of cells ; the
latter, however, has its constituent cells
crowded, while in Tetraspora the green cell-
contents lie scattered, mostly in groups of
two or four, in the gelatinous frond. Thuret
states that the cells possess long cilia in the
stage when they are imbedded in a contin-
uous frond (PI. 7. fig. 10). Development
by the ciliated cell-contents breaking out as
swarming zoospores. Two recorded British
species appear to be distinct, growing in
stagnant pools.

T. gelatinosa (PL 7. fig. 10). Frond gela-
tinous, soft, of irregular shape and division,
pale green; cells 1-10800 to .1-4200" in
diameter (Kiitzing, Tab. Phyc. i. p. 28).

T. lubrica. Frond green, elongated, me-
sentery-shaped, lobed and sinuated, lobes
often anastomosing; cells angulo-globose,
1-3600" in diameter (Kiitzing, /. c. pi. 30).
BIBL. Hassall, Alg. 300, pi. 78 ; Kiitzing,
Sp. Alg. 225; Tab. Phyc. i. ; Thuret, Ann.
Sc. N. 3. xiv. 248, pi. 21 ; Nageli, Einzell.
Alg. 71, pi. 2 ; Rabenht. Alg. iii. 38.
TETRASPORES. See SPORES.
TETRATAXTS, Ehr. — A Valvuline
Foraminifer, with four chambers in a whorl.
Fossil ( Carboniferous). (Parker and Jones.
Ann. N. H. 4. x. 259.)

TEXTILE FABRICS.— The components
of these are noticed under the heads of silk,
wool, fibrous and filamentous structures.

BIBL. Wiesner, Techn. Mikr.-, Schle-
singer, Mikr. Untersuch. d. Gespinntfasern,
1872; Button, M. M. Jn. vii. 259; Lat-
teaux, Man. Techn. Micr.

TEXTULA'RIA, Def ranee (TEXTILARIA,
Ehr.). — A protean genus of hyaline Fora-
minifera, having typically a binary series of
subglobular or subquadrate chambers ar-
ranged alternately on two sides of a longi-
tudinal axis, and usually increasing in size
from the oldest (at apex) to the youngest,
with a slit -like apperture in the wall of
each chamber ( T. cuneiformis, PL 23. fig. 47).
The shell is flattened in one direction in
Vulvulina, with oblique chambers and ter-
minal slit, V. gramen (PL 23. fig. 49) ; in
another, in Cuneolina, with transverse cham-
bers and a row of apertural pores in normal
position. Irregularly alternate and biserial
chambers, passing into a short linear row,
with a necked and rimmed aperture, consti-
tute Heterostomella ; Bigenerina has many
uniserial chambers, with a terminal pouting
mouth (B. agglutinans, PL 23. fig. 50).

THALAMOPORA.

[ 764 ]

THECAMONADINA.

Instead of the biserial form, frequently
the shell begins with a triserial arrange-
ment of chambers ( Verneuilina, with con-
tracted aperture ; Candeina?, with perforate
septa). The Verneuiline commencement is
often succeeded by the usual two alternating
rows (Gaudryina, G. pupoides, PI. 23.iig.48),
or by a linear growth with terminal aperture
( Tritaxia). The triserial varieties are some-
times twisted. If Vulvulina takes on the
linear growth, we have Venilina.

The early chambers of Textularia and its
modifications are not unfrequently coiled
(Spiroplecta) . Textularia (&P.) annectens
(PI. 23. fig. 52), from the Gault, commenced
spirally, proceeded biserially, and ended
with uniserial chambers.

Large Textularice are rarely porous and
translucent; they usually become sandy
(Plecanium).

Common in all seas, and fossil in all
formations from the Silurian upwards.

BIBL. D'Orbigny, For. Foss. Vien. 245;
Williamson, For. 75 ; Morris, Cat. Br. Foss.
43 ; Bronn, Index Pal. art. Text. ; Ehren-
berg, Mikrog.; Schultze, Org. Polyth. 62;
Carpenter, For. 189; Parker and Jones,
Ann. N. H. 3. xi. 91 ; 4. ix. 298, x. 189,
196, 259; Brady, Carb. For., Pal. Soc.
1876, 130.

THALAMOFORA, Reuss. — A large,
subcylindric, zoophytoid Foraminifer, com-
posed of superimposed chambers, with laby-
rinthic and perforated walls, arranged around,
and opening into, a central vertical cavity.
Thalamopora exhibits characters of alliance
with Polytrema, Carpentaria, Tinoporus,
Cymbalopora, and, through the last, with
Planorbnlina and others of the Rotalina. It
is among the Perforata what Dactylopora is
among the Imperforata. (Reuss, Geinifa's
Elbthalgebirge, 1872, 139.)

THALASSICOL'LIDA, Huxley. — A
family of Radiolarian Rhizopoda.

Char. Composed of structureless cysts,
single or aggregate, containing cellular ele-
ments and sarcode, giving off' radiate pseu-
dopodia, which sometimes run into each
other and form a network. Nucleus present,
but no contracting vesicle. Numerous yel-
low cells occur scattered through them ;
and occasionally a few may be seen suspended
within the external gelatinous structure.

The whole organism is permeated by spicula,
or sustained by a fenestrated shell. The
most common genera are Splicer -ozoum, Col-
losphcera, and Thalassicolla. They are ma-
rine, in tropical and subtropical seas.

BIBL. Huxley, Ann. N. H. 2. viii. 1851,
489; Qu. Mie. J*. iv. 1856, 72; Miiller,
Thalass.', Haeckel, Radiolarien, 1862 ; Wal-
lich, Ann. N. H. 1869, iii. 97.

THALES'TRIS, Claus. — A genus of
Copepodous Entomostraca. Ten species,
marine. (Brady, Copep., Ray Soc. ii. 120.)

THAMNO'LIA, Ach.— A genus of Cla-
dodei (Lichenaceous Lichens).

T. vermicularis ; on mossy earth ; rare.
(Leighton, Lich. Fl. 74.)
" THAMNOM'YCES, Ehr.— A genus of
Sphseriacei (Ascomycetous Fungi). It has
distinct asci and sporidia. (Berk. Br. Flor.
ii. pt. 2. 284; Fries, Sum. Veg. 382.)

THAUMAN'TIAS, Eschscholtz. — A
genus of Campanulariidse.

Char. Stem simple (or branched ?), rooted
by a thread-like stolon ; cells campanulate ;
polypes with a funnel-shaped proboscis ; re-
production by free medusiform buds.

T. inconspicua, Forbes. Common off the
Hebrides. (Hincks, Hyd. Zooph. 178.)

THAUMATONE'MA, Grev.— A genus
of Diatomaceae. (Grev. Mic. Tr. 1863, 76.)

THECA. — A term used very loosely in
the descriptions of Cryptogamic plants. In
the case of the Lichens and Fungi it is syn-
onymous with Ascus, a sac in which free
spores are developed ; these are called theca-
spores or ascospores, in contrast with BASI-
DIOSPORES or stylospores. In the higher
Cryptogamia, as Ferns, &c., it is used in the
sense of sporangium.

THECAMONADI'NA, Duj.— A family
of Infusoria (=Cryptomonadma and some
Astasiaea, E.).

Char. Usually coloured ; covered with a
non-contractile tegument, which is either
hard and brittle, or membranous; locomotive
organs one or more flagelliform filaments.

Many are Algee, or their spores. They
are minute, usually green, but some are red ;
and they often colour stagnant water from
existing in vast numbers. They are mostly
recognizable by their rigidity and the uni-
formity of their motion.

Dujardin subdivided them thus : —

A • , i' Body ovoid or j Tegument hard and brittle 1. Trachelo

"globular ( Tegument membranous 2

lliform

Two

Cryptomonas.

with a tail-like prolongation 3. Phacus (Euglena pt., E.)

folia'ceous 1 ; without a prolongation 4. Crumenula.

(Two similar filaments 5. Diselmis (Chlamidomonas, E.).

fil ml fa -,°ne flagelliform filament, and j Body prismatic or boat-shaped 6. Ploeotia.

8- / one trailing retractile filament J Body ovoid or pip-shaped 7. Anieonei

Several filaments Body prolonged into a point in front " *~

Anisonema.
Oxyrrhit.

THELIDIIM.

C 765 ]

THYRSOPORELLA.

BIBL. Dujardin, Infus. 323.

THELID'IUM, Mass.— A genus of Micro-
lichens parasitic on the thallus of Lecanorae.

Char. Spores subfusiform, 2-locular, co-
lourless. (Lindsay, Qu. Mic. Jn. 1860, 346.)

THELOCAR'PON, Nyl.— A genus of
Pyrenodei (Lichenaceous Lichens).

Four species. (Leightou, Lich. Fl. 439;
Lindsay, Qu. Mic. Jn. 1869, 345.)

THELOTRE'MA, Ach.— A genus of Pla-
coidei (Lichenaceous Lichens), containing
two British species. (Leighton, Lich. Fl.
238.)

THEO'RUS, Ehr.— A genus of Rotatoria,
of the family Hydatinaea.

Char. Eyes colourless, more than three,
cervical, in' two groups; foot forked; jaws
each with a single tooth

T. vi'rnalis (PI. 44. fig. 32). Toes small,
frontal hook absent. Aquatic; length 1-140
to 1-120".

T. uncinatus. Toes long, frontal (or
rather cervical) region with hooks ; fresh-
water ; length 1-240".

BIBL. Ehr. Inf. 454 ; Pritchard, Inf. 690.

THLIPSU'RA, J. & H.— A Cytheroid
Ostracode in the Silurian strata. (Jones
and Holl, Ann. N. H. 4. iii. 213.)

THO'REA, Bory.— A genus of Batra-
chospermeae (Confervoid Algae), of which
one species (T. ramosissima) occurs in Bri-
tain; its fronds are olive-black, branched
filaments, a foot or more long, about as thick
Fig. 740.

Thorea ramosissima.

Horizontal section of a filament (halved). The semi-
circular denser portion represents the axis, the loose
spreading branches the villi. Magnified 25 diameters.

as a crow-quill, with a villous surface. The
filaments are composed of radiating branched
cells, closely compacted into a kind of solid
axis, from which proceed lax, radiating ra-
niuli, forming the yillous surface. The
spores or sporangia! cells arise from these
ramules (fig. 740).

BIBL. Kiitz. Phyc. yeneralis, pi. 16, Sp.
Alff. o-°,4 ; Enij. But. Supp. No. 2f>48 ; Has-
sal], Alg. 64; Rabenht. AJg. iii. 418.

THOREL'LIA, Boeck. — A genus of
Copepodous Entomostraca. T. brunnea, on
Lamitutria. (Bradv, Copep. i. 9o.)
' THUIA'RIA, Flem.— A genus of Polypi,
of the Order Hydroida, and family Sertula-
riidae.

Char. Those of Sertularia ; but the cells
closely pressed to or imbedded in the stem
or branches. Two species :

T. thuia. Cells ovate-elliptical, acutish ;
vessicles pear-shaped. On shells from deep
water.

T. articulata. Cells ovate, obtuse or trun-
cate, vesicles elliptical ; rare.

BIBL. Johnston, Br. Zooph. 83; Gosse,
Mar. Zool. ii. 23; Hincks, Hyd. Zooph.

THU' JA, L.— A genus of Coniferee (Gym-
nospermous Plants), to which belongs the
arbor vitce of gardens, Thuja occidentalism
T. orientalis is placed by some authors under
another genus, Biota. The characters of
Coniferous wood, Gymnospermous ovules,
&c., may be observed in these plants (see
CONIFERS and OVULE).

THURAM'MINA, Brady.— A subglobu-
lar Arenaceous Foraminifer (0-5 mm.), with
perforate papillae; single and enclosing a
smaller chamber or group, and adherent.
Atlantic and Pacific. (H. B. Brady, Q. Jn.
M. Sc. n. s. xix. 45.)

THURIC'OLA, Kt.— A genus of Peritri-
chous Infusoria. Like Vaginicola, but sheath
with a closeable valve. Three species ; salt
and fresh water. (Kent, Inf. 718.)

THY'AS, Koch.— A genus of Hydrachnea
(Acarina). Like Hydrachna, but legs formed
for walking. T. venusta. (Koch, Uebers. ;
Murray, EC. Ent., fig.)

THYMELEA'CE^E.— An order of Di-
cotyledons to which the Spurge-Laurels
(Daphne) belong. In D. Lagetto ( = Lagetta
lintearia) the fibres of the liber are separated
into lozenge-shaped meshes, arranged in
such beautiful and easily-separable layers,
as to have acquired for the plant the name
of the LACE-BABK TREE.
See LIBEB.

THYRSOPOREL'LA, Giimb.— Giimbel
divides the Dactyloporideee (see DACTYLO-
PORA) into (I.) those with chambers: —
1. Haploporella ; segmented, annular, or
cylindrical (piled rings), with large cham-
bers and simple traversing canals (6 species,
recent and Tertiary) : 2. Lactyloporella ;
cylindrical, with large and subsidiary cham-
bers, and branched traversing canals (4
species, Tertiary). (II.) Those without
chambers : — 3. Thyrsoporella ; cylindrical

THYRSOPTERIS.

[ 766 ]

THYROID GLAND.

with simple, swollen, traversing canals, and
fascicules of smaller tubes (2 species, Ter-
tiary) : 4. Gi/roporella ; cylindrical, with
circular canals (14 species, Triassic and
Neocomian) : 5. Utena ; annular, hollow,
perforate (1 species, Tertiary).

BIBL. Giimbel, Abhandl. k. bayer. Akad.
Wiss. II. Cl. xi. 1872, p. 231.

THYRSOPTERIS, Kunze.— A genus of
Cyathese (Polypodiaceous Ferns), with glo-
bose, marginal sori, collected into a panicle

Fig. 741.

Fig. 742.

Thyrsopteris elegans.

Fig. 741. A fertile pinna.

Fig. 742. A pinnule converted into a cup-like sorus.
Magnified 20 diameters.

distinct from the sterile pinnae. ^Capsules
sessile, on a globose receptacle; indusium
inferior, cup-shaped, the mouth entire. T.
eleyans, tropical. (Hooker, Syn. 15.)

Fig. 743.

Fig. 744.

Thyrsopteris elegans.

Fig. 743. Vertical section of the same, with the spo-
ranges removed from the columella.

Fig. 744. Side view of a sporange. Magn. 100 diams.

THY'ROID GLAND.— The thyroid gland
is one of the vascular glands, or glands with-
out ducts.

It consists of rounded, closed, glandular
vesicles (fig. 745) surrounded by or imbedded
in a fibrous stroma (a), and aggregated into
roundish, elongate, or somewhat polygonal
acini or minute lobules, these being grouped
in secondary lobules, which unite to form

G-landular vesicles from the thyroid gland of a child.
a, intervening connective tissue; 6, basement mem-
brane ; c, epithelium.

Magnified 250 diameters.

lobes. The vesicles are from 1-600 to 1-240"
in diameter, the acini from 1-50 to 1-24' '.
The stroma is condensed around the lobules,
to form a fibrous coat.

The stroma consists of ordinary interlacing
bundles of connective tissue, with fine elas-
tic fibres, at its outer surface containing fat-
cells.

Fig. 746.

Glandular vesicles with colloid matter
Magnified 50 diameters.

The vesicles consist of a basement mem-

T11YSAXURA.

TIXTIXXUS.

brane (fig. 7-45 //), lined by a single layer of
polygonal epithelial eells (c),and containing
a yellowish, tenacious, albuminous liquid.

The capillaries form plexuses surrounding
the vesicles.

In goitre, the vesicles become greatly en-
larged, and confluent, so as to form 'cysts
containing colloid matter, with fat-globules
and crystals of cholesterine. The same con-
ditions, in a minor degree, are so frequently
met with, that they can scarcely be regarded
as abnormal. The epithelium is also often
found loose in the vesicles (fig. 746). The
minute arteries and capillaries are often
finind varicose.

BIBL. Kolliker, Mik. An. ii. 327; Forster,
Pathol.An. ii. 233; Verson, Strieker's Hist.
i. L><>7.

THYSANU'RA.— An Order of Insects
(Spring-tails), to which Lepisma, Petrobius,
Pod ura, and Lepidocyrtus belong. See IN-
SECTS.

BIBL. Lubbock, Thysanura, fyc., Ray
Soc. 1873 ; Murray, EC. Ent. 401.

TICHOTHE'OIUM, Fv.— A genus of
Microlichens parasitic on the thallus of
many crustaceous and subfoliaceous h'chens.

BIBL. Lindsay, Qu. Mic. Jn. 18G9, 347.

TILLE'TIA, Tnlasne.— A genus of Usti-
laginei (Hypodermous Fungi), forming the
Bunt, a kind of blight of various corn-grains,
in which the ears are attacked, and the in-
ternal substance of the grains is replaced by
a foetid, black powder, consisting of the
spores of the fungus. T. Caries ( Uredo Ca-
ries, D.C.) attacks wheat and other grain.
The interior of the ovaries of the corn is at
first occupied by an interwoven mycelium,
from which the globular spores arise on
short stalks; as the latter grow, the ears
become more or less deformed, the mycelium
disappears, and the spores are set free as a
pulverulent mass. The spores have a reti-
culated surface ; and their pedicel is often
found attached (PL 27. fig. 13). A distinct
species is found in wheat in the United
States. (See USTILAGINEI.)

BIBL. Berk. Br. Fl. ii. pt. 2. 375 ; Tu-
lasne, Ann. Sc. N. 3. vii. 112, pL 5 ; 4. ii.
161.

TILLI'NA, Gruber.— A genus of Holo-
trichous Infusoria. Free, renifonn, pha-
rynx curved ; longer cilia round the mouth
and the pharynx. T. magna ; freshwater.
(Gvuber, Zeitsch. wiss. Zool. 1879, Jn. Mic.
Soc. 1880 ; Kent, Inf. 514.)

TIM'MIA, Hedw. — A genus of Mniaceous
Mosses, approaching Polytrichum in habit,

and j\Iniinn in the form of the capsule. One
British species, Tinuniu amtriaca, on rocks
in Scotland.

TIN'EA, Fabr. — A genus of Lepidopterous
Insects, of the family Tineidce.

The small scales from the underside of
the wings of T. vestianella, the common
clothes' moth, have been proposed as test-
objects; but they can hardly be regarded as
such for object-glasses of the present day.
The longitudinal lines form the test-struc-
ture.

BIBL. Westwood, Introd.; Staintou,

nual of Butterflies.

TltfOP'ORUS, Carpenter (De Montfort).
— A many-shaped Foraminiferal genus of
the Globigerinida ; globular, subhemisphe-
rical, lenticular, or stellate ; areolated, gra-
nulate, and often spined (baculate). Com-
mencing as a spiral Rotaline (like Calcarina),
it soon heaps on each face subcyclical layers
of quadrangular chambers, with cribrate
floors and strong, perforated, radiating septa.
The spines consist of " supplemental skele-
ton," arising from some of the early septa,
with an extension of the "canal-system."
Gypsina, Carter, is an allied but less elabo-
rate form.

Recent, often in great abundance, as Tino-
porus baculatus of the Australian seas and
the Philippines.

BIBL. Parker and Jones, Ann. N. H. 3.
vi. 34 ; Carpenter, For. 223 ; Carter, Ann.
N. H. 4. iv. 215 ; 5. v. 444.

TIXTINXOD'EA.— A family of Hetero-
trichous Infusoria.

Kent includes in this family, Tintmnus,
Tintinnidium, Vasicola, and Strombidinopsis.

TIXTIXXID'IUM, Kt. — A genus of
Heterotrichous Infusoria. Like Tintinnus,
but contained in a mucilaginous cylindrical
sheath, adherent to foreign bodies. Three
species; marine and freshwater. (Kent,
Inf. Oil.)

TIXTINNOP'SIS, Stein.— A genus of
Heterotrichous Infusoria. Like Tintinnus,
but with two independent rings of anterior
cilia. T. beroidea, marine. (Kent, Inf. 617.)

TINTIN'NUS, Schrank. — A genus of
Heterotrichous Infusoria, family Tintin-
nodea.

Char. Single ; body contained in a cylin-
drical, sessile, bell-shaped carapace, to the
bottom of which it is attached by a stalk.

Many species.

T. inqmlinus (PI. 32. fig. 4). Body hya-
line or yellowish ; carapace cylindrical, hya-
line. Marine; length 1-240".

TISSUE.

[ 768 ]

TISSUES.

BIBL. Ehr. Inf. 294 ; id. Ber. Berl Ak.
1840 ; Duj. Inf. 561 ; Ann. N. H. 1879, iv.
21X); Clap, et Lach. Inf. 195; Kent, Inf. 603.

TISSUE, FIBRO-PLASTIC. — A term ap-
plied by Lebert to imperfectly developed
abnormal connective tissue. The separate
elements are often found diffused through
normal tissues, or products of inflammatory
exudation. They consist of rounded or
oblong cells, from 1-2300 to 1-1600" in dia-
meter, in a more advanced stage becoming
fusiform or angular, and finally forming di-
stinct fibres ; hence resembling the elements
of embryonic connective tissue (PI. 49. fig.
42). In some instances the development is
arrested at one of the early phases, so that
the tissue consists almost exclusively of the
rounded or the fusiform cells; and in others,
the cells enlarge and produce a number of
nuclei or secondary cells (PI. 38. fig. 10 c).

Fibro-plastic tissue or its elements are
met with in inflammatory effusions upon the
serous and synovial membranes (but rarely),
in the interstitial effusions of pneumonia,
especially when chronic, in cirrhosis of the
liver, in the products of suppurating sur-
faces, on the surface of chronic ulcers and
non-malignant fungoid vegetations^ in the
soft yellow vascular tissue occupying the
cancelli of ulcerated bones, in certain tu-
mours. &c.

BIBL. Lebert, Phys. Path. ; Wedl, Path.
Hist, ; Forster, Path. Anat. i. ; Rindfleisch,
Path. Gewebel.

TISSUES, ANIMAL.— The following syn-
optical arrangement of the principal animal
tissues, according to their structure, is in-
tended to facilitate reference to the various
articles scattered through the work.

A Simple.

1. Blast emic or protoplastic . Barcode.

2 Membranous .................. Basement membrane.

( Fatty tissue ; epithelium ;
nerve-cells ; simple

3. Cellular .................... ^ cartilage; unstriated

I. muscular fibre.

( Without secondary depo-

I sit ; true cartilage.

4. Slastemic and celluMr < with secondary deposit ;

5. Fibrous

f Connectivetissue; tendon;

\ ligament; elastic tis-

L sue; muscle.
6 Fibrous and cellular ...... Fibro-cartilage.

f Without secondary de-

posit. Vessels.
7. Tubular ..................... < with secondary deposit.

L Nerve-tubes.

B. Compound. Glands; mucous and serous mem-
branes ; skin synovial membrane ; teeth.

BIBL. Leydig, Hist. 1856; Morel, Hist.
1864 ; Kolliker, 2c. Hist. 1865; Briicke, Elem.
Organism. ; Beale, Simple tissues ; Exner,

Leitf. thier. Gewebe, 1873; Ranvier, Hist.
technique ; Thin, Hist. 1877 ; Schafer,
Pi-act. Hist. 1877; Gibbes, Hist. 1880;
Klein and Smith, Atlas Hist. ; Ork, Hist.
1881 ; Thierfelder, Atlm path. Hist. 1881 ;
Satterthwaite, Hist. 1881; Stirling, Hist.
1881.

TISSUES, VEGETABLE.— The tissues
of which vegetables consist are all composed
of cellulose sacs or cells, most of them re-
taining their primary form, constituting
cellular tissue, which makes up the greater
mass of plants; while others undergo com-
paratively slight, yet characteristic modifi-
cations in form, consistence, and in their
mode of uniun to form other tissues. The
tissues may be divided into groups on dif-
ferent principles; but for our purpose a
simple arrangement will suffice, based
chiefly on the character of the compound
tissues, leaving the secondary divisions to
be determined by the nature of the compo-
nent cells.

Cambium tissue, occurring in the growing
regions of all plants having stems, is com-
posed of minute cells of variable form,
densely filled with protoplasm, and without
intercellular passages. It is a transitional
structure, forming the first stage of all the rest.

Parenchyma, or cellular tissue, is com-
posed of cells in which the diameter is
not excessive in any one direction, and
the walls are comparatively thin. This is
divided by authors into many sections, ac-
cording to the form of the cells, the laxity
of their coherence, &c. The only distinc-
tions worth note are between : —

a. Parenchyma proper, where the cells
have polygonal forms.

b. Merenchyma, where the cells are round,
oval : &c.

c. Collenchyma, a form of cellular tissue
where the walls are greatly thickened
with softish secondary deposits ; it
occurs beneath the epidermis of many
herbaceous plants, in the fronds of the
larger Algae, of Lichens, &c.

d. Sderenchyma. Where the secondary
deposit or thickening is hard, as in the
bony cellular tissue of the shells, stones
of fruits, &c.

Prosenchyma. Cellular tissue, usually
forming the mass of wood and various
fibrous structures, where the cells are atte-
nuated to a p^oint at each end, the cells, or
fibres, being intercalated and applied side to
side.

Tela contexta. This name is used to

TISSUES.

[ 769 ]

TONGUE.

indicate the interwoven tissue formed by
the ramified jointed filaments of the my-
celium of Fungi, and the cottony substance
in the interior of the thallus of many
Lichens.

Fibro- vascular tissue is composed of vessels,
ducts, and prosenchymatous cells or "fibres"
associated in various ways, forming fibrous
or fibre-vascular bundles, which either re-
main distinct or cohere to form masses of
wood.

a. Fibrous bundles, occurring in liber, in
the outer part of many Monocotyledo-
nous stems, and in the stems of Mosses,
consist of cords formed of prosenchy-
matous cells, which are often of great
length.

b. Fibro-vascular burdles, composed of
vessels and ducts together with pros-
enchyma, form the woody fibres of
every part (except the bark) of all
plants above the Mosses.

c. Sieve-tubes or Clathrate tissue, found in
the bark of Dicotyledons and in the
vascular bundles of Monocotyledons.

Laticiferous tissue and Reservoirs for Se-
cretion, composed either of intercellular
passages lined by a proper coat, or of lines
of cells fused at their ends, so as to form
continuous branched canals ; they occur in
the bark, wood, and pith of the Flowering
Plants.

Epidermal tissue. Composed of cellular
tissue, forming a continuous firm layer over
the external surface of the higher plants.
It is composed usually of a single layer of
cells, and presents very varied appendages,
such as HAIRS, GLANDS, &c., and is per-
forated by STOMATA. Its outer surface is
rendered dense by the deposit of CUTICLE.
The epidermis is replaced, on stems, by the
CORK or suberous layer of BARK.

BIBL. Henfrey-Masters, Sot. ; Sachs,
Hot. ; V. Tieghem, Sot. 1881; and the Bibl.
of the above heads.

Fig. 747.

Tmesipteris tannensis.

TMESIPTERIS.— A genus oi Psiloteas
(Lycopodiaceae), remarkable for its peculiar
haoit and bivalved sporanges bursting by a
vertical crack. See LYCOPODIACEJE.

TOBACCO.— The leaves of Tobacco (Ni-
cotiana Tabacum and other species) may be
distinguished from the leaves of the plants
commonly used for adulteration by the pecu-
liar structure of the EPIDERMIS with its
hairs (PI. 2. fig. 16), and the form of the
section of its Fibro-vascular bundles. Paper,
which has been sometimes used, is still
more readily detected. The epidermis of
the dock-leaf (PI. 2. fig. 17), that of rhu-
barb (fig. 18), and of colt's-foot (fig. 19),
are also characteristic. As in other similar
cases, the nature of a foreign ingredient
can only be determined by careful compara-
tive investigations.

BIBL. Hassall, Food $c. ; Prescott, To-
bacco and its Adulterations, 1858.

TO'DEA, WiUdenow.— A genus of Os-
inundaceous Ferns (figs. 748-50). Four spe-
cies. Exotic.

Fig. 748. Fig. 749.

Fig. 750.

Todea afrieana.

Sporanges closed and bursting.
Magnified 40 diameters.

TOLYPOTH'RIX, Kiitz.— A genus of
Oscillatoriacese (Confer void Algae), appa-
rently not very satisfactorily defined. Has-
sall describes six species as British, of which
T. distorta (PI. 8. fig. 14) is said to be com-
mon, adhering to sticks, stems, &c. in stag-
nant water, forming tufts from 1-2 to 1" in
height, dark green when fresh, verdigris- or
blue-green when dry ; primary filaments
1-1800 to 1-1440" in diameter; joints about
as long as broad. Tolypothrix Dittwynii =
Desmonema, Eng. Bot. Supp. no. 2958.

BIBL. Kiitz. % Alg. 312 ; Tab. Phyc. ii.
pis. 31-33; Hassall, Alg. 240, pis. 68 & 69 ;
Rabenh. Alg. ii. 273.

TONGUE.— We have only space here to
notice the beautiful papillae of the tongue.

The filiform or conical papillae (fig. 755)
are whitish, very numerous, and occupy the
intervals between the fungiform papillae.

3D

TONGUE.

[ 770 ]

TONGUE.

The papillaa of the mucous membrane at
their bases (p, p) are conical, and covered
either at the end only, or all over the sur-
face with a number of smaller or secondary
papillae ; the whole being coated by an epi-
thelial investment (e)} terminating in a tuft

Fig. 751.

of free filiform processes (/). The inner
layers of the epithelium agree in structure
with that of the mouth, whilst the outer
layers, and especially the epithelium of the
processes, resemble rather the scales of the
epidermis, in their hardness, small size, and

Fig. 753.

Fig. 752.

Fig. 754.

Fig. 751. Fungiform papilla, covered by the epithelium 6 on one side, and with the secondary or simple papilla; p.
Magnified 35 diameters.

Fig. 752. The same, with the vessels; the epithelium e represented in outline, a, artery; v, vein; d, capillary
loops of the simple papilla ; c, capillaries in the simple papilla) of the mucous membrane at the base of the fun-
giform papilla. Magnified 18 diameters.

Fig. 753. Perpendicular section of a human circumvallate papilla. A, proper papilla ; JB, wall ; a, epithelium ;
b b, nerves of the papilla and wall; c, secondary papillae. Magnified 10 diameters.

Fig. 754. Follicular gland from the root of the human tongue, a, epithelium ; 5, papillae of the mucous mem-
brane ; c, areolar coat ; e, cavity ; /, epithelium lining it ; gg, follicles in the thick capsule. Magnified 30 diameters.

considerable resistance to the action of
alkalies and acids. The papillae themselves
consist of areolar tissue, with a large num-
ber of undulating nuclear fibres, each con-
taining a small artery («) and vein (v), with
intermediate plexus of looped capillaries,
and numerous nerve-tubes.

The fungiform or clavate papillae (fig. 751)
are reddish, distributed over the entire sur-
face of the tongue, and are very numerous
at its point. Each has at its base a club-
shaped mucous papilla, and is covered all
over with simple or secondary conical pa-
pillae (p,p) and a simple epithelial layer (e),

without filiform processes. The vessels (fig.
752) are more numerous, but otherwise re-
semble those in the filiform papillae.

The circumvallate or lenticular papillae
(fig. 753) consist of a flattened central pa-
pilla (-4), surrounded by an elevated wall or
ridge (B). The flat surface is furnished with
crowded conical secondary papillae (c), the
whole being covered with epithelium (a)
free from processes. The wall appears as a
simple fold of the mucous membrane, and
also exhibits beneath its smooth epithelial
coat numerous rows of simple, conical, se-
condary papillae. In other respects these

TONGUE.

[ 771 ]

TONGUE.

papillae do not differ essentially in structure
from the fungiform.

In some of the papillse of the tongue,
axial bodies are found resembling those in
the papillae of the skin.

The epithelial processes of the filiform
papillae are often covered by a fungus (Lep-
tothriv}, the mycelium closely surrounding
them, whilst some of the filaments project
from the surface.

Fig. 755.

Two human filiform papillse, one with epithelium.
p, p, papillae; a, v, artery and vein, with the capillary
loops ; e, epithelial covering ; f, its processes.

Magnified 35 diameters.

The glands of the tongue consist of mu-
cous and follicular glands.

The mucous glands resemble those of the
mouth (MOUTH).

The follicular glands are most numerous
between the epiglottis and the circumval-
late papillae, and are so superficially situated
as to form projections of the mucous mem-
brane. They form lenticular or globular
masses, from 1-24 to 1-6" in diameter, im-

bedded in the submucous tissue ; and in the
middle of the free surface is the orifice
(754 d) of a conical cavity (e), formed by a
depression of the mucous membrane. Each
gland forms a thick-walled capsule, sur-
rounded by a fibrous coat (c) continuous
with the deeper portion of the mucous
membrane, and lined internally by a pro-
longation of the mucous membrane with
papillae and epithelium (b, a) ; and between
the two are closed capsules or follicles (^),
imbedded in a fibrous and vascular basis.
The follicles are from 1-120 to 1-48" in
diameter, rounded or somewhat elongate,
whitish, composed of a coat of connective
tissue without elastic fibres, and with grey-
ish-white contents consisting of cells 1-60CO
to 1-4000" in diameter and free nuclei.

In the small portion of tissue constituting
one of the papillae of the frog's tongue,
Beale found striped muscular fibres, capil-
lary vessels, purely sensitive nervous fibres
forming an expanded terminal plexus at the
summit of the papilla, motor nerve-fibres
distributed to the muscle, nerve-fibres
around the capillary vessels, and a few very
fine nerve-fibres ramifying in different parts
of the papillae. All of these are imbedded
in and held together by connective tissue,
forming the body of the papilla, the summit
of which is surmounted by a peculiar epithe-
lium-like tissue, perhaps connected with
the nerves and belonging to nerve-texture,
while its sides are covered with ordinary
ciliated epithelium. The fur of the tongue,
which is usually considered to be composed
of epithelium, is stated by Butlin to consist
of Schizomycetous fungi.

BIBL. Todd and Bowman, Phys. ; Ward,
Todtfs Cycl. An. $ Phys.\ Salter, ibid.-,
Huxley, Mic. Jn. ii. 74; Beale, Phil. Tr.
1864, and How fyc. ; Hartmann, Mutter's
Archiv, 1863 ; Klein and Verson, Strieker's
Hist. v. 1: Butlin, St. Earth. Hosp. Rep.
1879,37.

TONGUE OF MOLLUSCA.— The tongue,
odontophore, or palate of the Mollusca, has
long formed an interesting microscopic ob-
ject on account of the elegant horny or
chitinous teeth situated upon it, in nu-
merous rows and in various patterns.

The tongue forms a shorter or longer
ribbon-like structure, attached behind to the
bottom of a sac or sheath, situated on the
lower wall of the pharynx. It is supported
by a cartilaginous cushion, over which it
works backwards and forwards by muscular
action.

3i>2

TONGUE.

[ 772 ]

TONGUE.

It exists in the Gasteropoda, the Ptero-
poda, and the Cephalopoda.

It consists of a central strip or band,
called the rachis, and two lateral bands, the

Fig. 755*.

Tongue of Whelk ; with separate teeth f- Magnified
10 diameters, the teeth 40 diameters.

pleurse. In the rachis, the teeth often rather
resemble overlapping toothed plates, the
teeth being straight, while the pleural teeth,
or uncini of the lateral bands, are usually
curved and more or less serrate.

Fig. 755**.

Kow of teeth of the tongue of the Periwinkle.
Magnified 120 diameters.

They may be easily examined in the lim-
pet (Patella) , the whelk (Bucdaum), or in
the freshwater snails, Lymnceus, Planorbis,
&c.

In the tongue of many terrestrial Gastero-
poda, as the snail (Helix) and slug (Limax)
the number of plates in each row is verj
considerable, amounting to 180 in the large
garden-slug (Limax maximus) ; whilst ii
many marine Gasteropoda, such as the com
mon whelk (Buccinum undatum), the tongue
has only three plates in each row, one bear
ing the small central teeth, and the two
others the large lateral teeth. Generally
speaking, the tongue of the terrestrial Gas
teropoda is short, and contained within. th
nearly globular head; but the closelyr'se
rows of teeth are usually very numerous
frequently more than 100, and in som
species as many as 160 or 170 ; so that th
total number or teeth may mount up, as i
Helix pomatia, to 21,000, and in Lima

maximus to 26,800. The transverse rows
are usually more or less curved, whilst the
ongitudinal rows are quite straight; and
he curvature arises on each side from the
central longitudinal row, the teeth of which
ire symmetrical ; whilst in those of the late-
ral portions of each transverse row, the
prominences on the inner side of each tooth
being suppressed, those on the outer side
are increased, this modification augmenting
in degree as we pass from the central line
towards the edges. The tongue of the
niarine Gasteropoda is generally longer, and
its teeth larger ; and in many instances it
extends far beyond the head, which may,
indeed, contain but a small part of it. Thus
in the common limpet (Patella) the princi-
pal part of the tongue is folded up, but per-
fectly free, in the abdominal cavity, between
the intestines and the muscular foot ; and
in some species its length is twice or even
three times as great as that of the entire
animal. In a large proportion of cases the
tongue exhibits a very marked separation
between the central and the lateral portions
— the teeth of the central band being fre-
quently small and smooth at their edges,
whilst those of the lateral are large and
serrated. The tongue of Trochus zizyphinus
is one of the most beautiful examples of
this form — not only the large teeth of the
lateral bands, but the delicate leaf-like teeth
of the central portion having their edges
minutely serrated. A yet more complex
type is found in the tongue of Haliotis, in
which the central band of teeth has nearly
straight edges instead of points, with on each
side a lateral band consisting of large teeth
shaped like those of the shark, and beyond
this, again, another lateral band on either
side, composed of several rows of smaller
teeth. Very curious differences also present
themselves" among the different species of
the same genus. Thus in Doris pilosa the
central band is almost entirely wanting, and
each lateral band is formed of a single row
of very large hooked teeth, set obliquely ;
whilst in Doris tuberculata the central band
is most developed, and contains a number of
rows of perpendicularly conical teeth, like
those of a harrow. In Dendronotus, the
central and lateral teeth are very finely and
beautifully serrated.

In Littorina, the periwinkle, the tongue is
2^ inches long, coiled like a watch-spring,
and contains about 600 rows of teeth.

The tongues may be preserved either in
the dry state, or in glycerine or in balsam .

TONSILS.

[ 773 ]

TORULA.

many of them in the latter medium forming
beautiful polarizing objects.

The imperfectly cleansed tongues, when
stained with Judson's dyes, also form beau-
tiful objects.

BIBL. Carpenter, Microscope', Thomson,
Todd's Cycl. An.SfPhys. iv. 1142; Ann. N. H.
2. vii. 86; Gray, ib. 2. x. 413; Macdonald,
ib. 1868, ii. 236, 1869, iii. 113; Maplestone,
3f». Mic. Jn. 1872, 45 ; Hogg, Tr. Mic. Soc.
1868 ; LovSn, (Efversiyt Kongl. Vetensk. Ak.
Forhandl. 1847 ; Troschel, Gebiss d. Schnec-
ken (36 pis,), 1875 ; Woodward, Mollusca.

TONSILS.— These organs may be re-
garded as consisting of from ten to twenty
follicular glands, resembling those found at
the root of the tongue, surrounded by a
common fibrous coat or capsule.

The blood-vessels are numerous, forming
elegant networks around the follicles. (Kol-
liker, Hist. ; Klein & Verson, Strieker's
Hist.}

TOPAZ.— The crystals of this mineral
consist principally of silicate of alumina,
with the fluorides of aluminium and sili-
cium.

Sections of topaz &c. often exhibit micro-
scopic cavities, frequently containing crys-
tals and one or two non-miscible liquids,
the latter sometimes including bubbles of
gas or vapour.

Brewster recommended the spherical
cavities as the best objects for examining
the aberrations of lenses, and as infinitely
preferable to globules of mercury.

BIBL. Brewster, Edinb. Phil. Tr. x. &
xvi. ; Microscope, 186.

TORQUATEL'LA, Lankester. — A
doubtful genus of Infusoria. Body rounded,
with an anterior funnel-shaped frill of un-
dulating membrane ; no cilia, vacuoles, or
nucleus. Marine, in Bay of Naples. (Lan-
kester, Qtt. Mic. Jn. 1874, 272.)

TOR'TULA, Hedw. See BARBULA.

TOR'ULA, Pers.— A genus of Torulacei.
The plants ordinarily referred here appear to
be somewhat heterogeneous in their nature.
In what may be considered the true species,
the chains of spores form the principal bulk
of the plants, little or no filamentous myce-
lium existing. Other forms very generally
included under this head agree in their
characters with OIDITJM, which itself is a
doubtful genus, probably founded on the
conidiiferous states of more perfect kinds.
But in T. sacchan (or cerevisice), the Yeast-
fungus, usually referred here, we find both

forms presented; for when actively vege-
tating in fermenting liquids, it presents the
characters shown in PI. 26. fig. 23, while,
while the liquid becomes exhausted, por-
tions of the fungus float to the top, and
produce a filamentous structure, terminating
in chains of spores, such as are represented
in PI. 26. fig. 24, and in fig. 756. The
simply beaded form is taken as the type of
a genus Cnjptococcus by certain authors,
some of whom consider it a Fungus, others

Fig. 756.

Torula sacchari (aerial form).
Magnified 200 diameters.

(Kutzing especially) an Alga. The same
varieties of form occur in the Vinegar-
plant ; and in both cases Penicillium glau-
cum seems invariably to succeed the pre-
ceding when kept at a moderate tempera -
ture. Thus between all these various forms,
together with Oidium lactis, there appears
to be a relation, not yet clearly made out,
indicating that they probably represent
different states of the same plant grow-
ing under different conditions of nutri-
tion and temperature. Further remarks on
this head are made under YEAST and VI-
NEGAR-PLANT. A growth similar to T.
sacchari presents itself sometimes in decom-
posing urine (PI. 26. fig. 7) from healthy
subjects ; and indeed scarcely any decom-
posing animal or vegetable fluid, in which
there exist fermentible elements, remains
long free from Torula-like growths, if left
exposed to the air (see FERMENTATION).

We find it impossible to give definite
characters for the species that have been
enumerated. T. herbarum is a common
form growing on decaying stems of plants ;

TORULACEI.

[ 774 ]

TOEULACEI.

it forms at first erect greenish tufts, which
afterwards become blackish, ramify and
form a black crust, the spores readily sepa-
rating. T. Sporendonema, a form growing
on decaying cheese, represents the Sporen-
donema casei of Desniazieres. T. Fumago
is now separated with other forms under
the genus CAPNODIUM. T. alternata also
is the type of the genus ALTEHNAHIA.

BIBL. Berk. Sr. Fl. ii. pt. 2. 359 ; Ann.
N. H. i. 263, vi. 439 ; 2. v. 460, xiii. 460 ;
Fries, Syst. Myc. iii. 499 ; Sum. 'Veget. 505 ;
Fresenius, Beitr. z. Myc. Heft ii. 68, pi. 6.
fig. 55 ; Oorda, Ic. Fungorum.

TORULA'CEI.— A family of Coniomyce-
tous Fungi, forming moulds and mildews on
decaying vegetable substances, or acting as
ferments in decomposing vegetable and ani-
mal fluids. They are compound microscopic

Fig. 757.

Fig. 759.

Fig. 757. Speira toruloides. Magnified 200 diameters.
Fig. 758. Gyrocerus ammonia. Magnified 200 diams.
Fig. 759. Trimmatostroma salicis. Magn. 200 diams.

cylindrical or beaded filaments, simple or
ramified, the joints of which (all or part)
separate from each other to form the spores.
There is no definite receptacle here; the
mycelium grows as a cottony web over or
in the infected body, or forms clouds or
flocks in liquids. Much obscurity prevails
respecting the genera included below, and
it is indeed doubtful whether any of them
are independent productions. Some species
of Torula, such as T. cerevisice (the Yeast-
fungus), appear intimately connected with
certain Hyphomycetous genera, perhaps

merely representing their conidiiferous forms
(see TOBULA). AcHORiOiSr, again, seems to
be merely the spermogonous form of a Peni-
cittium. Sporendonema is founded appa-
rently on imperfect observation ; S. muscce,
the true characters of which are given under
that head, has been renamed Empma ; and
its proper position is among the Saprolegnei ;
but it would appear to be referable to the
Mucorini. Dictyosporium, Speira, and Trim-
matostroma appear to consist merely of the
spores of some other genera; Gyrocerus
cannot be regarded as a perfect form ; and
indeed all the genera require a thorough
examination in a fresh state.

Synopsis of Genera.

Torula. Spores in beaded chains, simple,
readily separating, placed on a short con-
tinuous or septate pedicel (PI. 26. figs. 7 &
23).

Bispora. Resembling the last, but the
spores uniseptate.

Septonema. Resemblingthe preceding, but
having several transverse septa in the
spores.

Alternaria. Resembling the preceding,
but with cellular spores connected by a
filiform isthmus.

Sporidesmium. Spores in tufts, straight,
subclavate or fusiform, shortly stalked or
sessile, transversely septate or cellular.

Tetraploa. Spores sessile, quadriseptate,
coherent in bundles of four, each spore
crowned with a bristle.

Sporochisma. Filaments erect, simple, ex-
ternal membrane inarticulate, cell-contents
at length separating into spores, articulated
in fours, emerging.

Coniothecium. Spores without septa, col-
lected in heaps, finally separating more or
less into a powder.

Echinobotryum. Spores rounded-apicu-
late, collected in fascicles, attached on simple,
erect, annulated filaments.

Spiloccea. Spores globose, simple, adhering
firmly together and to the matrix, forming
spots laid bare by the separation of the epi-
dermis of the subject infected.

Sporendonema. Described as composed of
erect filaments, containing single rows of
spores in the interior. S. muscee (Empusa,
Colin) really consists of short, tufted, erect,
simple filaments, terminating in a bell-
shaped cell (spore or sporange ?), thrown off
with elasticity when mature.

TOURMALINE.

[ 775 ]

TRACHELINA.

Achorion. Mycelium somewhat ramose,
articulated, joints terminating in round, oval,
or irregular spores (conidia ?).

Speira. Spores connate into concentric
filaments, forming lamina? resembling a
horseshoe, finally separating,

Trimmatodroma, Spores more or less
curved, multiseptate, chained in beaded
rows, finally separating.

Gyrocerus. Spores connate into spirally
coiled filaments, finally separating.

Dictyotponum. Spores tongue-shaped, re-
ticularly cellular (fig. 172, p. 260).

TOURMALINE.— Sections of the crys-
tals of this mineral, cut parallel to the axis,
were formerly used as polarizers or ana-
lyzers. They are now usually replaced by
Nicol's prisms (INTRODUCTION, p. xx).
Crystals of the quinine-salt (QUININE) form
cheap substitutes for either. The crystals of
tourmaline belong to the rhombohedric
system. They consist principally of silica
with alumina, containing also boracic acid,
magnesia, iron, &c. j but their composition
is not constant.

Good tourmalines are transparent, brown-
ish or pinkish j the colourless ones do not
polarize.

BIBL. Pereira, Polarized Light', Nau-
mann, Mineralogie, 319.

TOUS-LES-MOIS.— A kind of fecula
consisting of the starch of species of Canna,
remarkable for the large size, great transpa-
rency, and numerous striae of the granules
(PI. 46. fief. 25). The mixture of any of the
common kinds of starch with Tous-les-mois
is readily detected by microscopic exami-
nation. The granules are excellent sub-
jects for studying the physical characters of
starch, in particular the appearance with
polarized light (PI. 39. fig. 40), &c. See
STARCH.

TOXOXIDEA, Donkin.— A proposed new
genus of Diatomaceae, the frustules of which
resemble those of Pleurosiyma, except that
the longitudinal line is curved on each side
of the median nodule in the same direction,
so as to resemble a bow. Two species.

T. Grer/oriana (PI. 51. fig. 24).
BIBL. Donkin, Micr. Jn. 1858, vi. 12 ;
Rabenht. Alg. i. 243.

TRACHE'A. See LUNGS.
TRACHE'^E OF INSECTS, &c— The re-
spiratory tubes of Insects and Arachnida.

Trachea (PI. 34. fig. 17 ; PL 85. fig. 2 h]
are cylindrical tubes containing air. They
are broadest at their origin from the spira-

cles, afterwards branching freely, the minute
branches being distributed to all parts of the
body and anastomosing freely. By reflected
light they appear white, with a metallic
lustre, or slightly iridescent ; by transmitted
light the smaller ones are black, the larger
usually of a violet tint.

The tracheae consist of two coats, between
which lies a spiral fibre (PI. 34. fig. 17) ; in
the larger trunks a second external envelope
exists. The fibre becomes more slender and
indistinct in the smaller trachea! branches,
until it finally disappears. The outer mem-
brane appears to arise from the confluence
of cells ; for in the tracheae of caterpillars
and other larvae of insects, the remaining
nuclei are visible (PL 34. fig. 17). The
inner coat forms a pavement epithelium.
The spiral fibre arises from the splitting up
of a homogeneous membrane deposited in
the space bounded by the confluent cells of
the outer membrane.

In many insects the tracheae are furnished
with dilatations forming air-sacs, in which
the spiral fibre is absent.

When larvae are fed with indigo or car-
mine, or when the dorsal vessel is injected
with colouring-matter, the tracheae become
coloured, which some authors believe to
arise from the nutritive liquid circulating
between the membranes of the tracheae ;
whilst by others this circulation, or the ex-
istence of a space between the tracheal
membranes, is denied.

BIBL. That of INSECTS ; Newport, Phil.
Tr. 1836, 529; Platner, Mullens Archiv,
1844, xxxviii.; Stein, VergL Anat. Insek-
ten ; Agassiz, Ann. Sc. Nat. 3. xv. ; Bassy,
ibid. ; Joly. ibid. xii. ; Blanchard, Compt.
Rend. 1851 ; Ann. N. H. 1852, ix. 74; Du-
four, Compt. Rend. 1851, Ann. N. H. 1852,
ix. 435 ; Meyer, Siebold $• Kolliker's Zeitschr.
i. 175 ; Moseley, P)>oc. Roy. Soc. No. 153.
vol. xxii. 344, 1874 ; Gerstacker, Siebold fy
Kolliker's Zeitschr. ii. 204, 1874; Landois,
Zeit. iviss. Zool. xvii.

TRACHEAE OF PLANTS.— This name
was formerly applied to the unreliable
SPIRAL Vessels of Plants, from their resem-
blance to the tracheae of Insects.

TRACHELI'NA.— A family of Holo-
trichous Infusoria.

Char. Body without regular spiral teeth
or foot ; parenchyma excessively contrac-
tile ; mouth and oesophagus very dilatable.

BIBL. Clap. & Lachm. Inf. p. 291.

TRACHELIUS.

[ 776 ]

TRAGACANTH.

Synopsis of Genera.

Mouth ter-
minal.

f Anterior part of /
body with a
conical appen-
dage.

' Body more or less cylin- /Mouth on the summit
drical, moving by-( of the appendage
turning on axis. ( Mouth at its base
, Body flat, swims without turning on axis
!( No lMr,incr /'Body attenuate in front
No inter- I cirri Pg1 Body not attenuate in
nal teeth. 1 ' \ front

I/acrymaria.
Phialina.
Trachelophyllum.
Enchelys.

No conical ap-<

\ Leaping cirri

^ pendage.

( Body attenuate in front
Internal teeth -( Body not attenuate in

Enchelyodon.

\ front

!CEsophageal

teeth present.

Mouth not

A bundle of cirri, simulating a foot

terminal.

No cesophageal

A row of spherical vesicles, each enclosing a very
refractive body

teeth.

/No lateral j A branched intestine...
Novesieles< laimna- 1 No branched intestine .
j A broad marginal lamina of compact
1 tissue

Trachelius.

Amphileptus.

Lozovhvlhtm.

TRACHE'LIUS, Ehrenb.— A genus of
Holotrichous Infusoria, fam. Trachelina.

Char. Mouth situated at the base of the
trunk-like prolongation, alimentary canal
apparently branched. No row of spherical
vesicles or lateral lamina.

T. ovum (Amphileptus ovum, Duj.), in
bog-water. Trachelius lamella (PI. 32.' fig.
is a Loxophylkim. (Clap. & Lachm. In:
345.)

TRACHELOCER'CA, Ehr.— A genus
of Holotrichous Infusoria ?= Lacrymaria.

T. olor—Lacrymaria olor.

T. viridis (PI. 31. fig. 33). Body green ;
neck as in the last; freshw. ; length 1-120".

BIBL. Ehr. Inf. 341 ; Clap. & Lachm.
Inf. 295: Kent, Inf. 514.

TRACHELOM'ONAS, Ehr— A genus
of Infusoria, family Cryptomonadina.

Char. Body enclosed in a spherical or
ovoid hard and brittle envelope, having a
small aperture, from which a long flagelli-
form filament projects; eye-spot present.
Freshwater.

T. volvocina (PI. 30. fig. 24 d, empty en-
velope). Spherical, green, brownish, or red ;
eye-spot red; length 1-865".

T. nigricans. Ovate-globose, green, black-
ish brown or reddish ; eye-spot brownish ;
length 1-1730".

T. cylindrica. Oblong-subcylindrical ;
bright green; eye-spot red; length 1-1000".

Other species.

The bodies represented in PI. 30. fig. 24
(b to #), and which are commonly found in
bog-water, probably belong here, with the
genera Chcetoglena(a), Chcetotyphla (fig. 26),
and Doxococcus (fig. 47). The margins of
the red envelope appear as a bright red
ring, on account of the greater thickness

traversed by the light. They are probably
spores of Algae.

BIBL. Ehrenberg, Inf. 47 ; Kent, Inf. 388.

TRACHELOPHYL'LUM, Clap. &Lach.
— A genus of Trachelina (Holotrichous In-
fusoria).

Char. Anterior part of the body with a
prolonged appendage, which has no circlet
of cirri ; body flat, without a lateral marginal
lobe. Swims without turning on its axis.
Two species ; freshwater. (Clap. & Lachm.
Inf. 306.)

TRACHYL'IA, Fr.— A genus of Micro-
lichens, parasitic on Pertmarice.

Char. Thallus granular ; apothecia cu-
puliform, sessile, black. Spores blackish,
1-septate. Three species, on old posts.
(Lindsay, Qu. Mic.Jn. 1869, 146 ; Leighton,
Lich. JP/470

TRACH'YTE. See ROCKS.

TRADESCAN'TIA, L.— A genus of
Commelynacese (Monocotyledons), com-
monly cultivated in gardens under the name
of Spider-worts. These plants are cele-
brated for having served as material for
some of the most remarkable observations
on the physiological processes of vegetables
— as the ROTATION of the cell-contents,
and the multiplication of the cells, so well
seen in the hairs of the stamens when young
(PI. 47. figs. 8 & 9). The stems, petioles,
&c. afford beautiful spiral, annular, and re-
ticulated vessels, &c.

TRAG'ACANTH.— A gum derived from
various species of Astragalus, not consisting
of a formless exudation, but of partly dis-
organized collenchymatous tissue which is
extruded from the medullary rays. It is
often used for fastening opaque objects, as,
when dry, its surface is dull, unlike gum-

TREBIUS.

[ 777 ]

TRICERATIUM.

arabic. We have some of the solution which
has been kept twelve years in a corked bottle
with a piece of camphor, and it is as good
as if freshly prepared.

TRE'BIUS, Kroyer.— A genus of Crus-
tacea, order Siphonostoma, family Caligidaa.

Char. Head in the form of a large buck-
ler, with the large frontal plates destitute
of sucking-disks ; thorax three-jointed, seg-
ments uncovered ; legs four pairs, with long I
plumose hairs, fourth pair slender and two- !
branched; antennae small, flat, and two-
jointed; second pair of foot- jaws two- I
jointed, and not in the form of a sucking-
disk.

T. caudatus. Found upon the body of
the skate. Male much smaller than the
female.

BIBL. Baird, Entomostraea, 280 ; Thomp-
son, Ann. N. H. 1847, xx. 248.

TREMATO'DA.— An order of Entozoa,
containing the flukes. See DISTOMA.

TREMELLI'NI.— A family of Hyrneno-
invi ctous Fungi, consisting of polymor-
phous, often convoluted or lobed, more or
less gelatinous masses, growing upon
branches or stumps of trees, in crevices of
the bark, or on the dead wood. The
hymenium extends over the whole of the
upper exposed surface, and, from the recent
researches of Tulasne, appears to present
remarkable characters. The gelatinous
substance of these Fungi is composed of
ramified filaments, with more or less effused
mucilage between them. In Tremella a
portion of the filaments terminate at the
surface at first in expanded globular cells
(PI. 27. Bgs. 3, 4), which become divided
by vertical septa into four somewhat pyri-
f orm cells (basidia) ; from each of these
arises a slender filament (sterigma\ which
terminates in a slender point tipped with a
globular spore (stylospare or basidiospore).
Other filaments coming to the surface in
like manner ramify extensively, with short
divergent branches, finally bearing nume-
rous minute globular bodies (spermatia),
solitary or in groups of four, which, like the
basidiospores,f all off and rest on the hy menial
surface, involved in jelly, but, unlike those,
do not germinate. The basidiospores are
about 1-3000" in diameter, the spermatia
about 1-12000". In Tremella mesenterica
the surface covered with basidiospores as-
sumes a whitish colour, the layers of sper-
matia and the jelly are orange.

In Exidia the production of the basidio-
spores is similar ; but the spores are reni-

form and unilocular, about 1-2500" long
and 1-5000" in diameter. Spermatia have
not been detected.

In Dacrymyces the basidia are represented
by simple clavate or bifurcate branches at
the hymenial surface, these terminating in
points bearing single reniform spores ex-
hibiting three septa (quadrilocular). In
germination some of these spores produce
a long filament from each loculus; others
behave differently, producing the spermatia
of the plant, each loculus sending out a
short pointed process bearing a globular
cellule exactly resembling the spermatia of
Tremella. Other examples of JDacrymyces
bear a different kind of reproductive bodies,
apparently representing conidia. In these
the peripheral filaments terminate in a mass
of many-jointed Tbrw/a-like processes, which
ultimately break up into the separate joints.
(See DACRYMYCES.)

BIBL. Berk. Br. Fl ii. pt. 2. 215; Ann.
N. H. 2. xiii. 406, pi. 15. fig. 4 ; Tulasne,
Ann. So. Nat. 3. xix. 193, pis. 10-12.

TRENTEPOH'LIA, Mart. = Chantran-
sia and Chroolepus sp.

TREPOM'ONAS, Duj.— A genus of Fla-
gellate Infusoria, family Monadina.

Char. Body compressed, thicker and
rounded behind, twisted in front into two
narrowed lobes, which are inflexed laterally,
and each terminated by a flagelliform fila-
ment, which produces a very lively rotatory
and jerking motion.

T. agilis (PI. 32. fig. 6). Body granular,
unequal; length 1-1160". In decomposing
marsh- water. (Dujardin, In/us. 294 ; Kent,
Inf. 300.)

TRIAR'THRA, Ehr.— A genus of Rota-
toria, of the family Hydatinaea.

Char. Eyes two, frontal ; foot simply
styliform ; body with lateral cirri or fins.

Movement jerking. Jaws two; each bi-
dentate.

T. longiseta (PI. 44. fig. 30). Eyes dis-
tant, cirri and foot nearly three times as long
as the body ; length 1-216".

T. mystadna. Eyes approximate; cirri
and foot scarcely twice as long as the body.

T. breviseta (Gosse). Cirri much shorter
than the body.

BIBL. Ehr. Inf. 446 ; Gosse, Ann. N. H.
1851, viii. 200 ; Pritchard, Infus.

TRICERA'TIUM, Ehr.— A genus of
Diatomaceae.

Char. Frustules free ; valves triangular,
areolar, each angle mostly with a minute
tooth or short horn,

TRICIIIA.

[ 778 ]

TRICHINA.

T.favus (PL 17. fig. 29). Valves plane
or convex, angles obtuse, with horn-like
processes ; areolae hexagonal ; marine ; dia-
meter 1-240' '.

T. alternans. Angles of valves slightly
elevated ; areolse circular ; marine.

T. striolatum (?). Angles subacute ; areo-
lation faint ; brackish water.

BIBL. Ehr. Ber. Berl. Ak. 1840 ; Smith,
Br. Diat. i. 26 ; Kiitz. Bacill. 138, and Sp.
Alg. 139 ; BrightweU, Micr. Jn. 1858, 153;
Rabenht. Alg. 'i. 315.

TRIO'HIA, Hall.— A genus of Myxo-
mycetes (Gasteromycetous Fungi) growing
upon rotten wood &c., characterized by a
stalked or sessile, simple, membranous peri-
dium, which bursts at the summit, whence
the densely interwoven free capillitium ex-
pands elastically, carrying with it the spores.
The capillitium is composed of tubular fila-
ments (Waters), containing spiral-fibrous
secondary deposits, like the elaters of Mar-
chantia (PI. 40. fig. 39). In some species
the elaters bear numerous little spinulose
processes. The genus is divisible into two
groups. In the first (Hemiarcyria) the
dehiscence of the peridium is obscurely cir-
cumscissile (fig. 760), the capillitium dense ;
these are always stalked, usually of reddish
colour when young. Some species have the
peridia fasciculate on a compound peduncle
(fig. 760), others separate. In the other
division ( Goniospora) the dehiscence of the
peridium is irregular, the capillitium lax,
the peduncle short or absent, the colour at

Fig. 760.

Trichia rubiformis.
Magnified 25 diameters.

first whitish, changing to yellow, and the
spores rather angular. In T. serpula and
reticulata the sessile peridia are irregular,
flexuous, serpentine or annular bodies ; in
most of the other species the peridia are

pyriform, turbinate, or of some analogous
form. The elaters (PL 40. figs. 39 & 40)
are interesting objects, and form good tests
for the defining-power of the microscope
under very high powers. They must be
mounted in a very thin stratum of liquid.

BIBL. Berk. Br. Fl. ii. pt. 2. 319 j Ann.
N. H. vi. 432, 2. v. 367 ; Fries, Syst. Myc.
iii. 182; Sum. Veg. 457; Greville, Crypt.
Fl. pis. 266, 281 ; Henfrey, Linn. Tr. xxi.
221 ; Currey, Mic. Jn. iii, 15, v. 127.

TRIC'HINA, Owen.— A genus of Ne-
matoid Entozoa.

T. spiralis (PL 21. figs. 16,' 17, 18), as
ordinarily seen, inhabits the human body,
forming opaque white specks, visible to the
naked eye, in the voluntary muscles. The
worms usually exist singly within a cyst situ-
ated between the muscular bundles (fig. 16).
At each end of the cyst is a group of fat-
cells resembling those of ordinary fatty tis-
sue. The cysts are about 1-50"" in length,
elliptical or oval, usually narrowed and
slightly produced at the obtuse ends, and
consist of numerous structureless laminae,
in which are frequently imbedded minute
granules consisting of fatty or calcareous
matter. The worm is cylindrical, narrowed
towards the anterior end, the posterior end
being obtuse and rounded. The integument
is transversely striated or annular, and ex-
hibits an anterior and a posterior longitudi-
nal muscular band. The mouth (fig. 17 a)
is situated at the anterior extremity, from
which a small papilla is sometimes protru-
dedl The first part of the alimentary canal
is very narrow, and leads to a broader sac-
culated portion; this behind the commence-
ment of the posterior half of the body ter-
minates in a funnel-shaped expansion (fig.
18 e), the remainder of the canal being
narrow and lined with pavement epithelium
(fig. 18 d). The manner in which the pos-
terior end of the alimentary canal terminates
is doubtful — whether directly continuous
with the anal orifice, or free in the abdomi-
nal cavity. Luschka describes three valves
as existing at the posterior end of the body.
At the commencement of the funnel-shaped
portion of the alimentary canal (fig. 166)
are two rounded glandular sacs. The re-
productive organs are not well known.
Just below the funnel-shaped portion of the
alimentary canal is the caecal origin of a
tubular sac (figs. 17 & 18 tf), containing a
dark granular-looking body (fig. 17 d-, fig.
18 e} near its commencement ; this extends
to the posterior end of the worm, where it
either terminates in the anus or in the

TRICHOCEPHALUS.

[ 779 ]

TRICHODACTYLUS.

abdominal cavity. Luschka regards this
as the male organ, and the dark-looking
body as the testis ; but no spermatozoa have
been detected.

Some of the cysts and worms are found
in a state of fatty degeneration, with gra-
nules or globules of fat, and calcareous
matter.

Trichina is admitted to the human body
with the food. It exists in two different
conditions. In one it is sexually immature:
and it then inhabits the muscles, of the pig
or rabbit for instance, in vast numbers, each
worm being coiled up in its capsule or cyst.
It is incapable of further development under
these circumstances. But if a portion of
the muscle be eaten by a warm-blooded
vertebrate animal and so introduced into
the alimentary canal, the immediate de-
velopment of young Tnctina is the result.
The immature worms escape from the cysts,
grow larger, develop sexual organs, and
produce viviparously a numerous progeny.
The young TrickbuB thus produced perfo-
rate the walls of the digestive system, and
after working into the muscles become
encysted.

It is important that every one should know
the appearance of meat infected with this
worm, as it produces serious disease, and
even death. It is stated that 8 per cent,
of the slaughtered American pigs contain
Trichina.

Three or four other doubtful species have
been described.

BIBL. Owen, Zool. Tr. i. 315 ; Luschka,
Siebold # Roll. Zeitschr. iii. 69; Bristowe
andRainey, Tr.PatA.Soc.v.274; Du].Ifel-
mint/ies, 293 ; Herbst, Ann. Sc. Nat. 3. xvii.;
Kobelt, Valentin's Rep. 1841 ; Leuckart,P«r. ;
Bakody, Sieb. fy Koll. Zeit. 1872, 422 ; Vir-
chow/Qw. Mic. Jn. 1861, 44; Cobbold,
Parasit. 149 ; and the BIBL. of ENTOZOA.

TRICHOCEPH'ALUSjGoeze.— A genus
of Nematoid Entozoa.

Char. Body elongate, composed of two
parts, the anterior longer and capillary, the
posterior becoming suddenly broader ; spi-
culum of male simple, long, and surrounded
by a sheath.

The species occur in the large intestine,
principally the caecum of man and the mam-
malia.

T. fh'spar (PI. 21. fig. 19, the male: fig.
21, the female).

Anterior portion of the body, spiral in the
male, containing the oesophagus only, or
the first moniliform portion of the intes*itine ;

posterior portion containing the rest of the
intestine and the reproductive organs. Anus
situated at the posterior obtuse end of the
body. Integument transversely striated,
and with a longitudinal band studded with
papillae (PI. 21. fig. 20). Oviduct termi-
nating at the point of junction of the two
portions of the body ; ova (fig. 21 a) oblong,
covered by a resistant shell, with a short
neck at each end.

BIBL. That of ENTOZOA.

TRICHOCO'LEA, Nees.— A genus of
Jungermannieae (Hepaticae), containing one
British species, T. (Jung.} tomentella, grow-
ing in moist places in the west and north of
England, Scotland, and Ireland. It is re-
markable for the character of the leaves,
which are cut up into compound capillary
segments, giving the plant a spongy texture.
Colour pale.

BIBL. Hook. Brit. Fl. ii. pt. 1. 127 ; Br.
Jung. pi. 36 ; Ekart, Synops. Jung. pi. 6.
fig. 49 ; Endlicher, Gen. Plant. Supp. 1. no.
472, 15.

TRICHO'DA, Miill.— A genus ofHolotri-
chous Infusoria.

Char. Free, ovate or club-shaped, trun-
cate in front ; mouth anterior, with a lip or
vibratile membrane; cilia very fine, oral
larger.

T. pur a, oblong attenuate in front ; in
putrid infusions, of hay &c. ; length 1-720".

T. carnium, in putrid-flesh water.

T. pyrum, in pond water.

T. angulata, Duj. (PI. 32. fig. 7), oblong,
obliquely and irregularly folded or angular,
with one or more superficial vacuoles ; fresh-
water; length 1-700".

BIBL. Ehr. Inf. 306; Dui. Inf. 395.

TRICHODACTYLUS, Dufour.— A ge-
nus of Acarea (Acarina).

Rostrum short, with minute setae j fourth
pair of legs longer than the rest, without
claws, but terminated by a very long seta.

T. Osmice. Glabrous, pale red, with two
marginal setae on each side ; legs and pos-
terior part of the body darker ; length 1-50' '.

T. Osmice, on an Ostnia ; T. Xylocopa, on
Xylocope ; another species in hornets' nests.

Murray unites the three genera, Hypo-
pus, Trichodactylus, and Ifomopus into a
family, Hypopidae ; while Me*gnin declares
them to be the nymphse of Acarea.

In all, the hinder pair of legs is rudimen-
tary, hairs replacing claws.

BIBL. Dufour, Ann. Sc. Nat. 2. xi. 276 ;
Gervais, Walckenaer's Aptires, iii. 266:
Murray, EC. Ent.26l j Megnin, Paras. 146.

TRIOHODECTES.

[ 780 ]

TRICHOGASTRES.

TRICHODEC'TES, Nitzsch.— A genus
of Philopteridae (Anoplura).

Char. Antennae filiform, three-jointed;
maxillary palpi none or inconspicuous;
mandibles two-toothed ; tarsi with one law.

T. latus (PI. 35. fig. 6). Abdomen pale
fulvous ; head and thorax ferruginous yel-
low; head subquadrate, with two black spots
in front, and a black lateral band on each
side ;' abdomen oval.

Common upon dogs, especially puppies.

Other species, upon cattle, the horse, ass,
deer, sheep, cat, &c.

BIBL. Denny, Anoplur. 186; Murray,
EC. Ent. 383 ; M^gnin, Paras. 80.

TRICHODER'MA, Pers.— A genus of
Fungi, placed by Fries among the Gastero-
mycetes. The plants are characterized by
a roundish peridium composed of inter-
woven, ramified, septate filaments, evanes-
cent at the summit; the spores minute,
heaped together, at first conglobated. T.
viride, growing on fallen trees, has a white
villous peridium, and dusky-green globose
spores. The peridia appear as scattered
spots 1-20 to 1-8" or more in diameter. It
is a conidiiferous state of Hypocrea rufa.

BIBL. Berk. Br. Fl ii. pt. 2. 323 ; Gre-
ville, Crypt. Fl. pi. 271 ; Fries, Sum. Veg. 417.

TRICHODES'MIUM,Ehrenb.— A genus
of microscopic Algae, apparently belonging
to the Nostochaceae, discovered by Ehren-
berg to produce the red colour over large
tracts in the Red Sea, and found also in the
Atlantic and Pacific Oceans by Darwin and
Hinds, and in the Chinese Sea. No vesi-
cular cells or spermatic cells have been de-
tected; hence the characters are as yet
imperfect. Montagne has separated the
plant of Hinds from Ehrenberg's ; and Kiit-
zing characterizes two species in his Sp.
Algarum, and figures them in his Tabuke
Phycologicce ; but neither the figures nor the
descriptions indicate any very marked diffe-
rences.

T. Ehrenbergii, Montagne. Blood-red (at
length becoming green) ; bundles widish,
confluent ; filaments 1-3000" in diameter,
joints about twice as wide as long. Found
floating in vast strata in the Red Sea by
Ehrenberg and Dupont, and in the Yellow
Sea (China).

T. Hindsii. Blood-red, with a strong
odour; bundles longish, slender; joints
twice or thrice as broad as long, transversely
granulated.

See also on the species, and on the red
coloration of the sea by plants, Montague's

papers in the Ann. So. Nat. 3. ii. 332,
vi. 262 ; 4. i. 81 ; Ann. N. H. 2. xix. 431 ;
Rabenht. Alg. \\. 161.

TRICHODI'NA, Ehr.— A genus of Peri-
trichous Infusoria, family Vorticellina.

Char. No tail, nor pedicle; cilia absent
from the surface of the conical or discoidal
body, but forming a frontal crown or a tuft ;
oral orifice not spiral.

T. pediculus ( Urceolaria stellina, D.) (PI.
81. fig. 16). Body discoidal, the under and
upper surfaces each with a crown of cilia.

Parasitic upon Hydra vulgaris and viridis.
Breadth 1-575 to 1-200". On the under
surface is an annular undulatory membrane ;
and within and at the base of this is a horny
ring, with an outer and an inner row of teeth,
forming an organ of adhesion.

T. mitra. Parasitic upon Planaria torva.

T. grandinella and T. vorax, on Halterina.

T. tentaculata. Body discoidal, cilia large,
forming a tuft; a styliform, tentacle-like
process present ; diam. 1-290".

BIBL. Ehrenberg, Inf. 265; Dujardin,
Inf. 527; Siebold, Siebold und Kolliker's
Zeitschr. ii. 361 5 Stein, Inf. 174; Claparede
£ Lachmann, Inf. 128 ; Kent, Inf. 647.

TRICHODINOP'SIS, Cl. and Lachm.—
A genus of Heterotrichous Infusoria. Free,
conical ; an anterior oral ring of cilia, and
a posterior suctorial disk. T. paradoxa, in
the mucous cavities of Cyclostoma. (Clap.
& Lachm. Inf. 133 ; Kent, Inf. 614.)

TRICHODIS'CUS, Ehr.— A genus of
Rhizopoda, family Actinophryina, D.

Char. Body depressed, stalkless ; seta-
ceous tentacles forming a simple row at the
margin of the body,

T. sol (PI. 32. fig. 8). Body suborbicular,
hyaline or yellowish, tentacles variable;
diameter 1-432 to 1-216".

BIBL. Ehr. Inf. 304.

TRICHOGAS'TER, Sterki.— A genus of
Hypotrichous Infusoria. Free, ovate, ven-
tral surface ciliated, a few larger cilia in
front and behind. T. pilosus, freshwater.
(Sterki, Zeits. wiss. Zool. 1878 : Kent. Inf.
764.)

TRICHOGAS 'TRES {Puff-balls} .—A fa-
mily of Gasteromycetous Fungi, character-
ized by the contents of the leathery peridium
breaking up when mature into a pulverulent
mass of spores and filaments, without a
central column, the whole being expelled by
the bursting of the case (see GASTEROMY-
CETES).

BIBL. Berkley, Ann. N. H. iv. 155 ; Tu-
lasne, Ann. Sc. Nt 2. xvii. 1,

TRICHOMANES.

[ 781 ]

TRICHORMUS.

TRICHOM'ANES, Linn.— A genus of I
Hymenophyllaceous Ferns, of elegant and i
delicate habit.

Fig. 761.

Fig 762.

Trichomanes alatum.

Fig. 761. A pinnule. Magnified 5 diameters.

Fig. 762. Section through a sorus, showing the vein
prolonged as a columella, and continued out beyond the
border. Magnified 25 diameters.

Fig. 763.

A sporange, with horizontal annulus. Magnified 100
diameters.

Many species ; tropical. T. brevisetum
(radicans'), British. (Hooker, Syn. 79.)

TRICHOM'ONAS, Donne.— A genus of
Flagellate Infusoria.

Char. Free, soft, ovate, with two anterior
and one posterior flagella, and a dentate
lateral undulating membrane ; no mouth.

T. batrachortim, in the intestine of frog
and toad.

T. vagmalis (PL 32. fig. 9). Body glu-
tinous, nodular, unequal, frequently be-
coming agglutinated to other objects; move-
ment vacillating; length 1-2500". Found
in morbid vaginal mucus.

T. limads (PL 32. fig. 10). Body ovoid,
smooth, pointed at each end; movement
forwards, by revolution upon its axis;
length 1-1600". Found in the intestine of
Limax agrestis.

BIBL. Dujardin, Infus. 299 ; Kent, Inf.
308.

TRICHONE'MA, From.— A genus of
Cilio -Flagellate Infusoria. Free, ovate,
variable j flagellum single; body with short

cilia. T. hirsuta: freshwater. (Kent, Inf.
469.)

TRICHONYM'PHA, Leidy.— A genus
of Holotrichous Infusoria. T. agilis, in the
intestine of the American white ant.
(Leidy, Proc. Ac. Philadelphia, 1881 ; Kent,
Inf. 533.)

'TRICHOPH'RYA, 01. & Lachm.— A
genus of Acinetina. Like Podophrya, but
fixed without a pedicle j tentacles in scat-
tered bundles; vesicles numerous; nucleus
band-like. Two species ; on the stalk of
Epistylis plicatilis, and on Entomostraca.
(01. & Lachm. Inf. 386: Kent. Inf. 811.)

TRICHOPH'YTON. See PARASITES.

TRIC'HOPUS, Clap. & Lach.— A genus
of Hypotrichous Infusoria.

Char. Body depressed, with a bundle of
long ventral cirri near the posterior end of
the body ; a tuft of caudal cilia, and a group
of pharyngeal teeth.

T. dysteria ; marine. (Claparede & Lach-
mann, Inf. 338.)

TRICHOR'MUS (Anabcma, Bory, Br6-
bisson, Kiitzing, Montagne, <fcc.). — A genus
of Nostochacese (Confervoid Algae), grow-
ing on wet earth, and rising to the surface of
lakes, brackish ditches, &c., forming an in-
determinate stratum, at first nearly colour-
less and transparent, with the filaments
sparingly scattered through the mass; the
filaments afterwards increasing rapidly in
number, causing the mass to become opaque ;
deep bluish green, and occasionally mottled
with brown, especially beneath. Filaments
mostly short and moniliform. Cells more
or less globular ; the spermatic cells resem-
bling the ordinary cells more in this than
in the allied genera. The filaments closely
resemble those of Nostoc ; and some of the
floating aquatic species can only be distin-
guished from that genus by the absence of
definite form or size, and of the hardened
periderm. It differs from Dolichospermum
in the globular shape of its sporangia, and
from Spheerozyga and Cylindrospermum in
the arrangement of its vesicular and sper-
matic cells, which are in Trichormus sepa-
rated by ordinary cells. In PL 8. fig. 2, we
have represented what appears to be a new
species.

T. flos-aqiice. Filaments flexuous or
curved, moniliform; cells orbicular, vesi-
cular ones larger, terminal and interstitial.
Ralfs, Ann. N. H. 2. v. pi. 8. fig. 2. Ana-
baina fl.-aq., Kiitz. Sp. Alg. ; Trichormus
incurvatus, Allman, Ann. N. H. xi. 163;
Hassall, Algce, pi. 75. Rising to the surface

TRICHOSPHJERA,

[ 782 ]

TRINACRIA.

of stagnant pools or other still waters, in
gelatinous bluish or green masses.

T. spiralis. Filaments coiled or spiral ;
vesicular and spermatic cells orbicular.
Ralfs, 1. c. pi. 8. fig. 3 (?). Anabaina spi-
ralis, Thompson, Ann. N. H. v. 81 ; Spiril-
lum Thompsoni, Hassall, Br. Fr. Algce,
pi. 75.

T. Thivaitesii. Filaments moniliform,
flexuous ; ordinary cells globular or nearly
so; vesicular cells larger, globular when
interstitial, ovate when terminal, ciliated;
sporangia oval, catenate. Ralfs, 1. c. pi. 8.
fig. 4. Salt marshes, forming thin, gela-
tinous dark-green patches, on damp soil or
the bottom of ditches, then floating and
abounding in spermatic cells.

T. oscillarioides. Filaments elongate,
flexuous; ordinary joints subquadrate; ve-
sicular cells barrel-shaped or elliptic, naked j
spermatic cells oval, catenate. Ralfs, I. c.
pi. 8. fig. 5. Bluish green, in brackish
ditches.

T. rectus. Filaments bright green,
straight. Ralfs, /. c. pi. 8. fig. 6 ; in pools.

BIBL. Ralfs, Ann. N. H. 2. v. pi. 8;
Rabenht. Alg. ii. 293.

TRICHOSPH^E'RA, Semper.— A genus
of Rotifera. T. cequatorialis is spherical,
the rotatory organ consisting of an equato-
rial zone of cilia; found among worms,
infusoria, &c. in the rice-field ditches of
Zamboanga; diameter 1-36." (Semper, Sieb.
fyKoll. Zeitschr. 1875, Mn. M. Jn. xiv. 237.)

TRICHOSPO'RIUM, Fr.— A genus of
Mucedines (Hyphomycetous Fungi), nearly
allied to BOTRYTIS, characterized by a cees-
pitose mycelium, whence arise fertile conti-
nuous filaments, bearing solitary, simple,
acrogenous spores. T. nigrum= Sporotri-
chum nigrum, Fries
(Syst. Myc.^j Botrytis
nigra, Link.

BIBL. Fries, Sum.
Veg. 492 ; Grev. Crypt.
FL pi. 274.

TRICHOS'TOMUM,
Hedw. — A genus of
Pottiaceous Mosses, so
called from the hair-
like peristome, resem-
bling closely that of
BARBULA (Tortula),
but with the teeth

Straight ^nstead of Triehostomumrigidulum.
twisted ; in T. rigidu- Fragment of the peri-
lum, however (fig'. 764), stome with filiform teeth,
there exists a slight Magnified 100 diameters.

Fig. 764.

curling even in this genus. The Tricho-
stoma grow on the ground and on stones.

TRICHOTHE'CIUM, Link (Diplospo-
rium, ejusd.). — A genus of Mucedines (Hy-
phomycetous Fungi), growing upon dead
sticks, herbaceous parts of plants, &c., form-
ing a csespitose entangled mycelium, from
which arise erect fertile filaments, bearing at
the summit a few acrogenous, free, didymous
spores. From some observations recently
published by Hoffmann, and confirmed by
Bail, the spores of T. roseum, when they
germinate, produce a mycelium whence
arise fertile filaments of Verticillium ru-
berrimum, the " spores " of which they con-
sequently consider to be the spermatia of this
plant. Several species are British, as T.
roseum, obovatum (Dactylium, Berk.).

BIBL. Berk. Er. FL ii. pt. 2. 348 ; Ann.
N. H. vi. 437, pi. 14 ; Greville, Crypt. FL
pi. 172 ; Fries, Sum. Veg. 492 ; Hoffmann,
Bot. Zeit. xii. 249 ; Bail, ibid. xiii. 673.

TRICHY'DRA, Wright.— A genus of
Hydroid Zoophytes.

Char. Stem creeping, branched; cells
rudimentary, consisting of very short tubular
processes at intervals on the creeping stem ;
polypes cylindrical, very slender and exten-
sile, with a short conical proboscis. T. pu-
dica, marine, on shells &c. (Hincks, Hyd.
Zooph. 215.)

TRILOCULI'NA, D'Orb.— A subgenus
of Miliola, with the chambers aggregated
on three opposite faces, embracing, three
only apparent.

Many species, both recent and fossil.
M. (TV.) trigomda (PL 23. fig. 4).

BIBL. Williamson, Rec. Brit. For. 84
(Miliolina) ; Carpenter, For. 78.

TRIMAS'TIX, Kt.— A genus of Fla-
gellate Infusoria. Free, ovate, with a lateral
membranous border; flagella three, ante-
rior^ one directed forwards, the others
trailing.

T. marina. In salt water with decaying
plants ; length 1-1400". (Kent, Inf. 312.)

TRIMMATOSTRO'MA, Corda (fig. 769,
774). An obscure genus of Toru-

cei (Coniomycetous Fungi), perhaps
founded on the spores of Phragmatotri-
chum. (Corda, Icon. : Fries, Sum. Veq.
475.)

TRINA'CRIA, Heib.— A genus of Dia-
tomaceee.

Char. Frustules with three broad, bi-
spined, equal-] engthed processes, margin
pearly, angles naked. Danube.

BIBL. Rabenht. Alg. i. 317.

p.

la

TRINEMA.

[ 783 ]

TRITON.

TRINE 'MA, Duj.— A genus of Rhizo-
poda, family Actinophryina.

Char. Carapace membranous, diaphanous,
elongate-ovoia, narrower in front, with a
large oblique lateral orifice ; expansions two
or three, filiform, very slender, as long as
the carapace.

T. acinus=Diffluciia enchelys, E. (PI. 32.
liir. 11, after Ehr. In Diijardin's figure the
expansions are represented as much more
slender.)

BIBL. Duj. Inf. 249; Clap. & Lach. Inf.
455.

TRINO'TON, Nitz8ch=Z«btf««m pt.

TRIOPHTHAL'MUS, Ehr.— A genus of
Rotatoria, of the family Hydatiusea.

Char. Eyes three, red, cervical, in a trans-
verse row; foot forked j jaws sin<rle-
toothed.

T. dorsalis (PI. 44. fig. 31). Body crys-
talline, turgid, suddenly attenuated at the
foot, which is half the length of the body.
Length 1-48 to 1-36". (Ehrenberg, Inf.
450.)

TRIPHRAG'MIUM, Link.— A genus of
Uredinei ' (Hypodermous Fun- -p,.
«), distinguished by their tri- Mf ,;,
locular spores (fig. 765). T.
ulmariee ( Uredo ulmarice, Brit.
Fl.~) grows upon the leaves of
Spiraea ulmaria, forming orange,
subsequently blackish, effused
patches, bursting from beneath m
the epidermis.0 Tulasne has ^
shown that it possesses all three A pedicellate
forms of reproductive structure j^nfe^ 350
of the Uredinei, viz. 1. spermo- diameters,
gonia with spermatia ; 2. Uredo-
fruits, with ellipsoid or globose stylospores ;
and 3. perfect fruits, arising either among
the stylospores or in special sori, containing
stipitate three-lobed spores (fig. 765), each
lobe of which is unilocular and exhibits a
single pore in its black tubercular outer coat.
The last germinate in the spring, and pro-
duce from each pore a tubular filament
which becomes divided into four or five
chambers, from three or four of which arise
single styliform processes (sterigmata), each
bearing a small smooth spherical sppridium.
The globular stylospores also germinate (in
the first summer), but produce only a long
filiform process, probably the rudiment of a
new mycelium. (See UREDINEI.)

BIBL. Berk. Br. Fl. ii. pt. 2.368; Tulasne,
Ann. Sc. Nat. 4. ii. 181, pi. 10 ; Fries, Sum.
Veg. 513 ; Currey, Micr. Jn. v. 126.

TRIPLO'CERAS, BaU.= Docidium sp.

TRIPOSPO'RIUM, Corda.— A genus of
Dematiei (Hyphomycetous Fungi), charac-
terized by the three-lobed septate spores.
T. elegans (fig. 766) has been found in this

Fig. 766.

Triposporium elegans.
Magnified 200 diameters.

country on bare oak-trunks. Another spe-
cies, T. Gardneri, forms a blight in the coffee
plantations of Ceylon.

BIBL. Berk. Ann. N. H. 2. vii. 98 j Sortie.
Jn. iv. 8.

TRITAXTA, Reuss. See TEXTULAEIA.
(Reuss, Site. Ak. Wien, xliv. 383.)

TRITICEL'LA, Dalyell.— A genus of
Ctenostomatous Polyzoa. Cells moveable ;
no gizzard. Three species. (Hincks, Polyz.

TRITON, Laur. (water-newt).— A genus
of Reptiles.

If a male and female T. cristatus (fig. 767),

one of the common water-newts, be kept in
a glass jar with healthy water-plants, they
will lay their eggs upon them. The larvje
are very beautiful microscopic objects for
showing the circulation in the gills and
tail, the chorda dorsalis and the embryonic
tissues; they should be kept in a vessel
separate from the parents ; otherwise these
will devour them.

The injected skin of T.palustris, the large
water-newt, forms a beautiful opaque object,
showing the loose capillary network, which

TROCHAMMINA.

[ 784 ]

TRYPANOSOMA.

contrasts well with the brilliantly mottled
skin.

BIBL. Bell, British Reptiles.

TROCHAM'MINA, Parker and Jones.—
A variable genus of Arenaceous Foramini-
fera, very near Lituola ; shell opaque, sandy,
smooth ; moniliform, serpentine, folded,
discoidal, or subnautiloid and rotalioid ;
segmentation mostly obsolete except in the
last. Very many species or varieties, recent
and fossil. The discoidal forms constitute
Reuss's Ammodiscus. Tr. incerta, PI. 23.
fig. 14.

BIBL. Parker and Jones, Q. J. Geol. Soc.
xvi. 304 ; Ann. N. H. 4. iv. 386 j Carpenter,
For. 141.

TROOHIL'IA, Duj.— A genus of Hypo-
trichous Infusoria, family Ervilina.

Char. Body irregularly oval, narrower in
front, where there are some cilia ; carapace
obliquely furrowed, slightly twisted, and
terminated behind by a moveable pedicle.

T. sigmoides {PL 32. fig. 13) ; fig. 12 re-
presents the animal undergoing transverse
division ; marine. Two other species.

TROMBIDI'NA.— A family of Acarina.

Char. Palpi with the last joint obtuse,
the last but one unguiculate, the second
very large; legs for walking, with two
claws ; eyes usually latero-anterior.

Principal genera : Anystis, Cheyletus, Me-
aamerus, Pachygnathus, Raphignathus ,
Rhyncholophus, Smarts, Tetranychus, and
Trombidium.

TROMBID'IUM, Latr.— A genus of
Trombidina (Arachnida).

Char. Palpi large, free ; mandibles un-
guiculate; body turgid, bearing the four
posterior legs, and an anterior narrow
moveable prominence, upon which the eyes,
the four anterior legs, and the mouth are
situated ; anterior legs longest ; legs seven -
jointed.

The species are numerous, and not well
characterized.

T. phalangii (PI. 6. fig. 37). Body sub-
triangular, angles obtuse ; of a velvety ap-
pearance, from the presence of numerous
plumose hairs ; eyes two, placed upon auri-
cular appendages.

An external parasite of Phalangium (the
harvest-spider) and insects, at least in its
early hexapodous stage.

T. elongatum. Crimson ; eyes approxi-
mate. Found under stones.

T. cinereum (PI. 6. fig. 40) (Rhyncholo-
phus ciner., Dug.). Body with brown and
greyish- white spots ; hairs spathulate ; eyes

t wo ^ on each side. Length 1-12". Found
in ditches amongst plants and stones.

T. autumnale (PI. 6. fig. 38) (Leptus au-
tumn.'). The harvest-bug. This well-
known arachnidan insinuates itself into the
human skin in autumn, causing troublesome
irritation. It is found on plants and the
stubble of corn-fields, and may easily be
caught by tying a white pocket-handker-
chief around the legs, and walking through
stubble-fields. The young form with six
legs is most frequently met with.

T. aurantiacum, on the black Ite&n.- Aphis.
Other species.

T. (Atoma) parasiticum, on the house-fly.
Other species.

BIBL. Duges, Ann. 8c. N. 2. i. 36 j Ger-
vais, Walck. Apteres, iii. 178 ; Johnston,
Tr. Berwick. Nat. Club, 1847, 221 ; Koch,
Deutschl. Crust. Myriap. #c.; Murray, EC.
Ent. 128.

TRUNCATULI'NA, D'Orb.— A sub-
genus of Planorbulina. Shell discoidal,
plano-convex, thick or thin, lobular or neat,
adherent by the flat face ; orifice slit-like,
slightly apparent above and continued be-
neath, along the line of suture, as far as the
second or third chambers.

Many recent and fossil species. PL (Tr.}
lobatula (PL 24. fig. 9); very common,
attached to sea- weeds.

BIBL. Williamson, Rec. For. 50; Car-
penter, Foram. 207; Parker & Jones, Phil.
Trans, civ. 381.

TRYBLIONEL'LA, Smith.— A genus of
DiatomacesD.

Char. Frustules free, linear or elliptical
in front view ; valves plane, with parallel
transverse (tubular ?) striae, and subniarginal
or obsolete alae.

In some a median line is present, in
others not. The alae are not marginal, as
in Surirella, but arise from the surface of
the valves, as shown by the diagram of a
transverse section in PL 17. fig. 32.

T. scutellum (PI. 17. fig. 30). Valves
elliptical, with a median longitudinal line ;
alse very short ; striae faint ; marine ; length
1-140".

T. gracilis(¥\. 17. fig. 31). Frustules
linear, narrowed at the ends ; valves linear,
acuminate, strisB coarse ; alse distinct ; fresh
and brackish water ; length 1-200".

Four other species.

BIBL. Smith, Brit. Diatom, i. 35; Rabenh.
Alg. i. 347.

TRYPANOSO'MA, Gruby.— A genus
of Flagellate Infusoria. Free, compressed ;

TUBER.

[ 785 ]

TUBERCULARIA.

one side thin, undulating, frill-like ; ante-
riorly produced into a long flagellate appen-
dage ; no mouth.

T. sangwnu, in frog's blood? length
1-600"; T. Eberthi, in the intestines of
poultry. (Gruby, C'ompt. Rend. 1843 ; Kent.
Inf. 218.)

TUBER, Mich. See TUBER ACEI.

TUBERA'CEL— A family of Ascomyce-
tous Fungi, growing underground or upon
the surface, of more or less round form, and
solid, fleshy texture, excavated with sinuous
cavities lined by asci containing usually
four or eight spores, elegantly reticulated
or spinulose (figs. 768-770). The internal
Fig. 768.

Choiromyces leonis.

Fig. 763. A peridium. Nat. size.
Fig. 769. An aacus with spares. Magnified 400 dia-
meters.
Fig. 770. Vertical section of a peridium.

substance either dries and grows hard, or
falls into a flocculent powder with age.

Tuber cibarium is the common truffle.
Sections of the marbled internal substance
show this to be composed of interlacing
branched filaments, forming fleshy convo-
lutions, between which serpentine cavities
are alternately excavated j branches of the
filaments free at the surface of the lacunae
bear spherical sacs (asci), each containing
four globular spores of yellow-brown colour,
having an elegantly reticulated outer coat.
When the spores germinate, they produce
a subterraneous cottony mycelium, which
after a time presents vinous nodules, in the

interior of which the peridia are developed ;
as these advance, the villous coats gradually
vanish, together with the mycelial structure,
and the mature peridia appear free, either
a little beneath (Tuber cibarium) or upon
the surface ( T. album) of the soil (see also
ELAPHOMYCES).

BIBL. Berk. Br. Fl. ii. pt. 2. 227; Tulasne,
Ann. Sc. Nat. 2. xvi. 5 ; Monog. Fung. Hy-
pogai, 1851 ; Ann. N. H. 2. viii. 19 ; Les-
piault, Ann. Sc. Nat. 3. ii. 316 ; Vittadini,
Monog. Tuber. ; Monog. Lycopod., Mem.
Turin\Acad. 2. v. 145.

TUBERCLE or TUBERCULAB MATTER.
— Tubercle consists of lymphatic corpuscles
contained in the meshes of a very delicate
reticulum, or a transparent homogeneous
tissue (PI. 38. fig. 8). ^ The ceUs vary in
size, and many contain a small distinct
nucleus. In addition to these, there are a
few larger cells containing two or even three
nuclei. The nucleated cells are exceedingly
destructible, so that often more free nuclei
than cells are visible. In most cases the
tubercle appears to consist entirely of closely
crowded nuclei or so-called tubercle-cor-
puscles (PI. 38. fig. 9 a), about 1-5000 to
1-4000" in size, oblong-angular, and un-
affected or simply rendered paler by acetic
acid (fig. 9 b).

Tubercle appears to originate most fre-
quently from tne tissue which surrounds the
small arteries in every situation, constituting
the lymphatic sheaths. The small cells in
this situation multiply at separate centres,
and thus miliary nodules are produced
around the vessel ; and as they gradually de-
velope, they compress the vessel, and may
finally occlude it. Tubercle invariably
undergoes a retrogressive change ; this com-
mences in the centre of the granulations,
and consists in the atrophy and incomplete
fatty metamorphosis of the closely crowded
cellular elements, constituting what is
termed caseation. The translucent and grey
granulations thus become opaque and yel-
lowish, the yellow tubercle being merely a
stage of the grey granulation. The casequs
tubercle subsequently softens, or may gra-
dually dry up into a firm cheesy mass, which
becomes ultimately calcified.

BIBL. Green, Path. Anat. 1871, 145;
Rindfleisch, Path. Hist. 1878.

TUBERCULA'RIA,Tode.— A supposed
genus of Stilbacei (Hyphomycetous Fungi),
but apparently only preparatory forms of
Sphaenaceous Fungi. T. wdgaris is a state
of Nectria (Sphceria) cinnabarina ; it is ex-
8l

TUBIOLAVA,

[ 786 ]

TUBURCINIA.

tremely common in autumn and winter, on
dead sticks, damp wooden palings, stumps,
&c., forming scarlet-orange rounded nodules,
or irregular fleshy masses, sometimes more
or less stipitate, the surface at a certain stage
exhibiting the ends of the filaments termi-
nating in chains of cells breaking up into a
pulverulent substance. These cells are pro-
bably the conidia of the Nectrice.

TUBICLA'VA, Allinan.— A genus of
Athecate Hydroid Zoophytes.

Char. Stems erect, simple or branched,
arising from a creeping stolon ; polypes cla-
viform, with scattered filiform tentacles.
Reproduction by means of fixed sporosacs
in clusters on the body of the polype, behind
the posterior tentacle, or on very short stems
developed on the creeping base.

BIBL. Hincks, Hyd. Zooph. 10 ; Allinan,
Ann. N. H. 3. xi. 9.

TUBICOLA'RIA, Ehr.— A genus of
Rotatoria, fam. Floscularisea.

Char. No eye-spot ; disk f our-lobed ; stalk
long, contained in a transparent gelatinous
sheath. T. najas, jaws with four teeth ;
on Letnna. (Ehrenberg, Infus. ; Pritchard,
Inf.)

TU'BIFEX, Lamk.— A genus of Annu-
lata, order Setigera,

Char. Body filiform, attenuated at the
ends, pellucid, with four rows of setae — two
dorsal and two ventral.

The worms live and burrow in the mud of
stagnant pools or the still parts of rivers,
giving it a bright-red appearance. When
the water or mud is disturbed, the red
patches instantly disappear, from the re-
traction of the animals. Length from 1-5
to 3-4" or more.

They are transparent, and show well the
alimentary canal, with its peristaltic actions,
and the cilia lining it, the blood-vessels and
their movements, with the loops bathed
in the chylaqueous liquid, and the coiled
water- (respiratory or renal) vessels with
their cilia.

BIBL. Schmidt, Mailer's Archiv, 1846,
406; Duges, Ann. Sc. Nat. 2. xv. 319;
Johnston, Ann. N. If. 1845, xvi. 443 ; Lan-
kester, Qu. Mic. Jn. 1871, 180.

TUBULA'RIA, Linn.— A genus of
Hydroid Zoophytes, family Tubulariidse.

BIBL. See TUBULABIIDJE.

TUBULA'RIID^E.— A family of Athe-
cate Hydroid Zoophytes.

Char. Polypes flask-shaped, with two sets
of filiform tentacles, one oral, the other near
the base.

Tubular ia. Stem twisted, branched or
unbranched ; tentacles filiform in two rows ;
e^g-gerins or gonophores on short footstalks,
clustered at the bases of the lower tentacles.

Corymorpha. Partly enclosed; polypidom
short, thin, membranous, swollen at the base,
| which is immersed in the sand; polype
single, head club-shaped, encircled at the
base by long filiform tentacles, and a circle
of short ones around the tip.

Ectopkura. With free medusiform sexual
buds.

BIBL. Hincks, Hyd. Zooph. 114; Lister,
Phil. Tr. 1834 ; Johnston, Br. Zooph. 48 ;
Mummery, Qu. Mia-. Jn. 1853, 28; Wright,
Ed. Neiv Phil. Jn. 1858, 113; Allman,
Ann. N. Hist. July 1859, and July 1864 ;
Van Beneden, Tubulaires.

TTJBULIP'ORA, Lam.— A genus of In-
f undibulate Cyclostomatous Polyzoa, of the
family Tubuliporidse.

Three British species ; some of them
common upon shells, sea-weeds, &c.

PL 41. ng. 30 represents a species (not
British).

BIBL. Johnston, Br. Zooph. 266 ; Hincks,
Polyz. 442.

TUBULIPOR'Hm— A family of Infun-
dibulate Cyclostomatous Polyzoa.

Char. Polypidom calcareous, massive,
circular, lobed or divided dichotomously ;
cells long, tubular, with a round, prominent,
unconstricted orifice. Genera :

Tubidipora. Wart-like, with a defined
base; cells suberect, aggregated or in im-
perfect rows, more or less free at the end.

Diastopora. Incrusting, undefined; cells
alternate, tubular, horizontal, immersed,
with a raised circular orifice.

Idmonea. Divided dichotomously, erect ;
cells on one side, tubular, in transverse
rows, divided into two sets by a median
longitudinal line.

Piistulipora. Erect, cylindrical ; cells
semi-immersed, on all sides, orifices pro-
minent.

Alecto. Creeping, adherent, irregularly
branched ; cells horizontal, in one or more
rows, their ends free.

BIBL. Johnston, Br. Zooph. 264 ; Gosse,
Mar. Zool ii. 7.

TUBURCINIA, Fries.— A genus of
Ustilagiuei (Hypodermous Fungi), occur-
ring in vegetable tissues.

T. scalies produces the disease called
scab in potatoes; T. trientalis occurs on
leaves of Trientalis Europcca ; conidia are
produced on the underside of the leaves.

TUMOURS.

[ 787 ]

TUMOURS.

BIBL. Berk. & Br. Ann. N. H. 2. v. 464 ;
Cooke, Handb. 516 ; De Bary & Worouin,
Beit. v. pis. 1-3.

TUMOURS. — Non-inflammatory uew
formations. Under this head we shall
pake a few remarks upon some of the more
interesting elements 01 certain tumours and
other morbid growths.

Sarcoma. The tumours included under
this name, comprise the fibro-plastic, fibre-
nucleated, recurrent fibroid, and themyeloid.
They consist of connective tissue, retaining
more or less the embryonic type j and the
varieties depend upon the size and form of
the cells, and the nature of the intercellular
substance. The cells are either round,
fusiform, or myeloid — larger cells containing
many nuclei or secondary cells. The inter-
cellular substance is scanty, homogeneous,
granular, or fibrillated.

Fibrous tumours consist of fully developed
connective tissue. The fibres are sometimes
firm and dense, at others lax. The cells or
connective-tissue corpuscles are very few in
number, and usually only become visible on
the application of acetic acid. They are
often minute spindle-shaped, fusiform, or
stellate bodies, the latter having processes
of varying length, which communicate with
those from neighbouring cells.

Gummata are new formations, consisting
of an incompletely organized granulation
tissue. They soon undergo retrogressive
changes; hence the growth is ultimately
made up of atrophied, degenerated, and
broken-down cell products, imbedded in an
incompletely fibrillated tissue.

Myxomata consist of a translucent and
succulent connective or mucous tissue, the
intercellular substance of which yields
mucine. They are of a peculiar soft gelatini-
form consistence, and of a pale greyish or
reddish-white colour. On scraping the cut
surface they yield a tenacious mucilaginous
liquid, in which may be seen the cellular
elements. The cells are angular and stel-
late, with long anastomosing prolongations
and trabeculce ; others are isolated, fusiform,
oval, or spherical, with one or two nuclei.

Lipomata. Fatty tumours resemble adi-
pose tissue, and consist of cells containing
fat united by a variable quantity of connec-
tive tissue.

The Enchondromata and Osteomata con-
sist of cartilage and bone respectively ; and
the Lymphomata are new formations con-
sisting of lymphatic, or, as it is usually
termed, adenoid tissue.

The Papillomata, such as warts, horny
growths, polypi, originate from the skin
and mucous membranes, of the tissues of
which they may be called exaggerations.
The adenomata, or tumours of glands, are
new formations of gland tissue. They
resemble the racemose glands, and consist
of small grouped saccules or tubes filled
with squainous or cylindrical epithelium-
cells.

The carcinomata, or cancers, consist of
cells of an epithelial type, without any
intercellular substance, grouped together
irregularly within the alveoli of a fibrous
strorna. There are four varieties — scirrhus,
encephaloid, epithelioma, and colloid. These,
although all possessing the same general
characters, present certain structural dif-
ferences which serve to distinguish them.
The cells are comparatively large, varying
considerably in diameter, of a rounded,
oblong, or ovate form, usually in no definite
order, in the intervals of the fibres (PL 38.
figs. 11 & 12), although sometimes in the
meshes formed by the aggregation of the
fibres into loose bundles (fig. 17).

The interspaces of the cells and fibres are
occupied by a pale yellowish or colourless
liquid j and the cells are so loosely imbedded
in the fibrous basis, that on scraping the
surface of a section of a cancer, numerous
cells are found in the juice thus obtained.

The number of fibres present varies accord-
ing to the stage or development of the
cancer. In hard or schirrous cancer, they
predominate, the cells being few ; while in
soft, encephaloid, or medullary cancer they
are scanty, the cells being very abundant ;
globules of fat usually abound in the latter
forms.

Other varieties of cancer have received
special names. Thus, when the capillaries
are very numerous and distended, extrava-
sated blood being also frequently present,
we have fungus hsBmatodes; when the
fibres are grouped into bundles, forming
marked areolse, filled with a gelatinous
substance, we have colloid or gelatiniform
cancer (PI. 38. fig. 18) ; again, when the
cancer cells abound in pigment, we have
melanotic cancers.

In epithelial cancer, or epithelioma, the
general arrangement of the elements is not
strikingly altered, but the papillae of the
skin are hypertrophied, the epithelial cells
more numerous than natural, sometimes
containing many nuclei or secondary cells,
and the intercellular juice is more abundant.
3E2

TUNICATA.

[ 788 ]

TUNICATA.

The flattened epithelial cells are also often
arranged around the papillae in the form of
concentric rings or nests, resembling fibres ;
but the cell-structure is at once rendered
evident by the addition of solution of
potash.

In regard to cells generally, an insuper-
able difficulty is met with in discovering
the exponent of their power, as it might be
termed; thus the embryonic cells or cor-
puscles in an early stage are undistinguish-
able from each other, yet some grow into
fibres of connective tissue, others into
nerve-tubes, &c. Chemistry lends no aid
here, and the difficulty will probably ever
remain.

In the examination of tumours and other
morbid growths, sections should be made
with a Valentin's knife, the elements being-
first observed in water, and then in the
natural fluid. The sections and elements
are best preserved in water.

BIBL. Paget, Tumours and Surgical Pa-
thology ; Bennett, on Cancer, and Ed. Mn.
Jn. vii. & viii. ; Redfern, ibid, xi. ; and the
Tr. Pathol. Soc., passim ; Green, Path.
Anatomy ; Rindfleisch, Path. Gewebel.

TUNICA'TA.— A class of Animals, be-
longing to the Invertebrate subkingdom Mol-
lusca.

Char. Marine ; often microscopic ; bodies
single, social, or aggregate; acephalous;
enclosed in an elastic tunic with two orifices,
one oral and branchial, the other anal
or cloacal ; a large atrial system, the
pharynx communicating with it by bran-
chial slits ; respiration branchial, branchiae
pharyngeal; nervous system a ganglion;
circulation effected by a tubular heart, with
vessels, the current of blood varying in di-
rection ; hermaphrodite ; evolution accom-
panied by metamorphosis, or following the
law of alternation of generations (PL 18.
figs. 10 & 20).

The smaller Tunicate, are commonly found
aggregate, and investing rocks, stones, and
shells ; some are adherent to seaweeds, &c.,
a few are free ; many are common on the
sea-shore.

The body is sac-shaped or elongate, some-
times slightly constricted so as to exhibit a
thorax, abdomen, and a posterior portion or
postabdomen. The outer coat, test or
tunic, is cartilaginous, leathery, gelatinous,
or membranous ; and consists partly of cel-
lulose, often containing calcareous spicula.
Within this is another coat, the mantle,
usually adhering to the former at the orifices

only, and containing numerous muscular
fibres. The oral orifice (PL 18. fig. 10, a),
or opening of the usually dilated pharynx
or branchial cavity, within which is placed
the branchial apparatus (6), leads to the
mouth. This is slit-like, and leads into a
narrow ossophagus ; to this succeeds an
expanded stomach (/), which terminates
in a longish intestine with a heemal curve
(i), and ends at the base of the cloaca
(V*), which opens externally at the atrial
orifice. Within the oral orifice, at the com-
mencement of the branchial cavity, is a ring
of rudimentary tentacles.

The branchial apparatus in the pharynx
(fig. 10, b) consists of numerous cross bars,
with slit-like openings between them ; these
are ciliated, and copiously supplied with
networks of blood-vessels. The slits open
into the atrial system. The current excited
by the cilia draws the water through the
oral orifice into the pharynx, where it tra-
verses the openings, flowing outwards to
collect in the cloaca, from which it is ex-
pelled through the atrial orifice. In some
of the larger Tunicata, the branchial appa-
ratus is strap-shaped, and traverses the body
obliquely.

The heart (h) is a spindle-shaped sac,
enclosed in a pericardium (p)} and situated
near the base of the body, the principal
vessels running on the dorsal and ventral
surface of the branchial apparatus. The
current of blood varies in direction, being at
one time expelled from one end of the
heart, at others from the other. In those
Tunicata which are connected by a common
tube, the blood passes freely from one to
the other.

The nervous system consists of a single
ganglion (fig. 10, g), situated between the
two orifices, and giving off its principal
branches to the branchial sac and the ali-
mentary canal. In some an eye is present,
resembling the compound eye of the Arti-
culata, and with a reddish pigment.

Moreover an auditory capsule has been
noticed in some genera.

The liver (/) consists either of a dark
glandular layer lining the alimentary canal,
or of distinct glandular caeca.

The Tunicata are reproduced by gemma-
tion, by sexual organs, and by intermediate
generations.

The testis (t) and ovary (o) are usually
strap-shaped organs, either adherent to the
alimentary canal, or situated in the poste-
rior part of the body ; the former has a long

TURBELLARIA.

[ 789 ]

TYMPANIS.

spermatic duct (d), which opens into the
cloaca, into which also the ova or larvae are
discharged, to escape by the posterior orifice.
The larvae often resemble at first tadpoles
with three anterior sucker-like organs, by
means of which they adhere to foreign
bodies to complete their development, the
tail gradually disappearing. In Appendicu-
Inria the larval form persists through life.

The larval caudal appendage has been
shown to have a rod-like body, which has
been compared to the chorda dorsalis of
Vertebrate,

In the large free Tunicata, the inter-
mediate generations are united into long
chains, the final product being a sexual
individual ; but into the further structure
of these curious beings we have no space
to enter.

Synopsis of the Families.

* Attached; mantle and test united only at

the orifices.
BOTKYLLID^!. Bodies united into sys-

tems.

CLAVELINIDJE. Bodies distinct, but
connected by a common root- thread.
Bodies unconnected.

** Free ; mantle and test united throughout.

PELONJEAD^E. Orifices near together.
SALPIDJE. Orifices at opposite ends.

BIBL. M.-Edwards, Ascid. Comp., and
Mem. de VInstitut, 1842 ; Forbes and Han-
ley, Br. Moll i. 1; Siebold, Vergl. An. 234;
Lister, Phil. Tr. 1834; Huxley, Comp. An.]
Rupert Jones, Todds Cyclop., Art. Tunicata;
Allinan, Qu. Mic. Jn. vii. 86 ; Gegenbaur,
Vergl. An. ; Nicholson, Zool. 363.

See APPENDICULABIA, BOTBYLLID^J,
CLAVELINOXS:, &c.

TURBELLA'RIA.— An order of Annu-
lata.

TURBINEL'LA, Schultze.— A genus of
Ichthydine Rotatoria.

BIBL. Schultze, Mullens Archiv, 1853,
241 ; Pritchard, Inf. 381.

TURMERIC. See CURCUMA.

TUR'RIS, Lesson.— A genus of Athecate
Hydroida, family Clavidse.

Char. Stems short, rooted, bearing the
polypes on their summits; polypes clavi-
form, with scattered filiform tentacles. T.
>i<>(/!e<-fa, in the Solent, Ilfraconibe, &c.
(Hincks, Hyd. Zooph. 13.)

TYD^EUS, Koch.— A genus of Trombi-
dina (Acarina). Transverse line present ;

no eyes; legs six-jointed. T. mufabilis,
very minute, on damp earth or moss. (Koch,
Uebers.-, Murray, EC. Ent. 120.)

TY'PHOID CELLS.— In typhoid fever
certain special uninuclear cells are formed,
which contain more protoplasm and are
larger than lymph-cells, pus-corpuscles, and
white blood-corpuscles; these assume an
irregular and often polygonal form. De-
generative changes speedily commence, and
the cells break up, mostly by fatty meta-
morphosis, into oily debris capable of re-
absorption. The cells are found not only
in the intestinal structures, but also in other
organs; forming medullary masses on the
pleural surface, and inside the sarcolemma of
muscles.

BIBL. Rindfleisch, Path. Geweb. 317.

TYM'PANIS, Fr.— A genus of Phaci-
diacei (Ascomycetous Fungi), consisting of
horny bodies growing on branches of trees,
breaking out through the bark. T. con-
spersa (fig. 771) grows upon Rosaceous

Fig. 771.

Tympanis conspersa.

A collection of perithecia, more or less mature, burst-
ing through the bark. Magn. 10 diams.

trees, T. saligna on -rx 779

the privet. In the
former the perithecia
are collected in tufts ;
they are first closed,
afterwards opening
into cups, the disk of
which is occupied by
the hymenium, bear-
ing long and broad
asci containing nume-
rous spores, and some-
times also septate

stylospores simulta- ^

neously. In T. saligna cup-like perithecia.

the perithecia OCCUr Magnified 20 diameters.

only two to four to-
gether. Spermogonia exist (which are oblong
or conical bodies) intermixed with the peri-
thecia, perforated by a terminal pore (re-
sembling perithecia of Sphcerici) ; these are
lined with delicate branched filaments bear-
ing minute corpuscles (spermatia), which

sone of thepe

TYPHLINA.

[ 790 ]

ULVACE.E.

when mature escape from, the pore in a
tendril (as in Cytispora) if moistened or
pressed (see also CENANGIUM).

BIBL. Berk. Br. FL ii. pt. 2. 210 ; Ann.
N. H. 2. vii. 185 ; Hook. Jn. Bot. iii. 322 ;
Tulasne, Ann. 8c. Nat. 3. xx. 143, pi. 16.
figs. 15^ 16 . ;prjeg? $um ye 399 Qre_

ville, Crypt. Fl. pi. 335.

TYPH'LINA, Ehr.— An imperfectly ex-
amined genus of Rotatoria, of the family
Philodinaea. T. viridis (PL 44. fig. 33).
Found in Egypt. (Ehrenberg, Inf. 483.)

TYROO'LYPHUS. See ACARUS.

TYRO'SINE.— This substance is gene-
rally found associated with leucine. It
forms silky-white needles, often in stellate
groups, difficultly soluble in water, and en-
tirely insoluble in alcohol and ether. When
warmed with sulphuric acid, and percMoride
of iron is added, it is rendered violet. The
little white grains found upon anatomical
preparations preserved in spirit consist of
tyrosine. (Hoppe-Seyler, Analyse Chim.:
Frey, Hist. 51.)

U.

U'LOTHRIX.— A genus of Confervacege
(Conferyoid Algae), allied to Draparnaldia
and Stiyeoclonium. They consist of un-
branched filaments, adhering loosely toge-
ther to form a mucous stratum, growing
upon stones &c. in fresh water. The fila-
ments are composed of short hyaline cells
(PI. 9. fig. 6), the green contents of which
are at first granular, adhering to the walls
(a), then contracted into transverse bands
(b). Contractile vesicles have been ob-
served in the cells of some species. Ac-
cording to recent observations, macrospores
with four cilia occur singly or in twos,
in certain cells ; while in others, numerous
biciliated microspores are formed, which
conjugate and produce resting spores ; these
again give rise to zoospores, from which
new filaments arise.

U.zonata. Filaments 1-960" in diame-
ter, joints about as long (JLyngbya zon.}
Hass. pi. 59. figs. 2, 3, & 6).

U.pectinalis. Filaments 1-1800" to 1-960"
in diameter, joints half or a fourth the
length ; fertile cells swollen (Hass. pi. 60.
figs. 1-5).

U. crispa. Filaments very long, 1-600" in
diameter, joints half or a third as long {Con-
ferva bicolor, Eng. Bot. p. 2288).

U.floccosa. Filaments 1-2100" to ]800" in
diameter, joints about as long (Lyngbya
floccosa, Hass. pi. 60. figs. 1 & 2).

U. punctalis. Filaments 1-3000' ' to 1-2500"
in diameter, regularly torulose ; joints two
and a half times as long as broad (Lyngb.
punct.t Hass. pi. 60. fig. 4 j including per-
haps L. virescens and L. vermicularis).

U. speciosa. Filaments 1-780" to 1-420"
in diameter, curled; sterile joints half or a
third as long.

U. mucosa, Thuret (PI. 9. fig/ 6). Pale
green or yellowish, slimy ; joints usually as
long as broad, sometimes shorter, 1-3000" in
diameter.

BIBL. Kiitzing, Sp. Alg. 345 ; Tab. Phyc.
ii. ; Hassall, Alg. 219; Thuret, Ann. Sc. N.
3. xiv. 222, pi. 18 ; Rabenht. Alg. iii. 365 ;
Cramer, Bot. Zeit. 1871 j Dodel, Pringsheirrfs
Jahrb. x, 417.

UL'VA, Linn. — A genus of Ulvaceae
(Confervoid Algae), here taken in the sense
of Thuret. The plants are all marine, con-
sisting of broad, green, simple, or lobed,
membranous fronds, growing upon rocks
and stones. The cells are rounded-angular
(PI. 9. figs. 2 & 3), and are at first filled
with amorphous green colouring-matter,
which subsequently becomes collected into
masses («), ultimately converted into nu-
merous zoospores. Under the influence of
light, those soon " swarm " and break out
from the cells by a pore in the outer wall
(fig. 3 b). The emptied cells give a pale
colour to the parts of the frond where they
are situated. The zoospores appear in two
forms, some large and bearing four cilia
(tig. 3 c), others much smaller and pos-
sessed of only two cilia (fig. 2b). The
fronds in which the latter occur are gene-
rally of a yellower colour. Thuret has seen
both kinds germinate. As defined by that
author, the British species stand as fol-
lows : —

U. Lactiica, L. Frond broadly ovate or
oblong, 6 to 18" long, and several inches
wide.

/3. latissima. Frond 3' or more long, 18"
or more wide ; found in the muddy water
at the entrance of harbours (Phycoseris My-
riotrema, Kiitz. Sp. Alg.} = 17. orbiculata.

U. Linza, L. Frond linear-lanceolate,
6 to 24" long, A to 1J" wide.

BIBL. Harvey, Mar. Alg. 216, pi. 25 B;
Thuret, Mem. Soc. Cherbourg, ii. ; Ann. Sc.
Nat. 3. xiv. 224, pi. 20 ; Greville, Harvey,
Kiitzing, Algce ; Rabenht. Fl. Eur. Alg. i.
316.

ULVA'CE^E.— A family of Confervoid
Algae. Marine or freshwater Algae, con-
sisting of membranous, expanded, saccate

ULVINA.

[ 791 ]

UREDINE^.

or tubular, sometimes filiform fronds, com-
posed of spherical or polygonal cells, united
together firmly into layers, either single or
double. Reproduced 'by roundish spores
formed from the whole contents of cells, or
by ciliated zoospores formed in twos, fours,
or many in each cell.

Uh'fi. Frond plane, simple or lobed,
formed of a double layer of closely packed
cells, producing zoospores,

latteromorp/ta. Frond hollow, simple or
branched, of a single layer of closely packed
colK forming a sac or tube; with zoospores.

M«n ostroma. Frond flat or saccate, simple
or lacerate-lobed, forming a single layer of
evils scattered in a homogeneous membrane ;
with zoospores.

Pra*iola. Fronds membranous, lacerate-
lobed, formed of a single layer of cells in
simple or compound lines, or "in groups mul-
tiples of four. Spores formed from the
whole contents of the cells, motionless.

ScJiKOf/oninm. Fronds filiform, dilated
here and there into fiat ribands, containing
two or four rows of cells ; spores formed
from the whole contents, motionless.

See PROTODERMA and SCHIZOMERIS.

ULVJ'NA. See CRYPTOCOCCACE^.

UMBILICA'RIA, Fee(%ro^om,Ach.).
— A genus of Phyllodei (Lichenaceous Li-
chens). U. puziulata grows on rocks in
various parts of Britain. It is remarkable
for the tubercles or hollow papillae occurring
on its surface. The apothecia are flat, at
first black, at length tuberculate. Sper-
inogonia also occur, in the form of little
tubercles containing a nucleus of densely
packed sterigmata, enclosed by a thin black
rind. The species in which the disk of the
apothecia is concentrically plicate form the
proper Gyrophora of Ach. ; they occur on
mountain-rocks. Several other species.

BIBL. Hook. Br. Fl. ii. pt. 1. 223; Tu-
lasne, Ann. Sc. Nat 3. xvii. 207, pi. 5. figs.
5-12 ; Schaerer, Ennm. crit. 25 ; Leighton,
LicJt. Fl. 142.

UMBONEL'LA =LEPBALiApt. (Hincks,
Poh/zoa, 316).

UNILOCULI'NA, D'Orbigny.— A sub-
genus of Miliola.

Char. Shell regular, equilateral, globular;
chambers completely embracing, regularly
wound round the axis, one onty apparent,
this making a complete revolution around
the preceding ; cavity simple ; orifice single,
with a tooth.

In the other genera of the family, each
chamber occupies only half the circumfer-

ence, whilst here it forms a complete circle.
One species, U. Indica (PI. 23. fig. 2).
(D'Orb. For. Fos. Vien. 261.)

URATES, See URIC ACID.

URCEOLA'RIA, Ach.— A genus of Par-
meliacea) (Gymnocarpous Lichens), included
under Parmelia by Fries, but agreeing in
almost every particular with LECANORA.
U. scruposa, the commonest species, STOWS
on heaths, walls, and rocks. The disk of
the apothecia is black, and the border
crenated. The spores are cellular or multi-
locular (PL 37. fig. 17). The spermogonia
are scattered over the thallus, sometimes in
the outer wall of the (thallodal) border of
the apothecia ; they are very inconspicuous,
on account of tlie light colour of their
ostiole.

BIBL. Hook. Br. Fl. ii. pt. 1. 175 ; Tu-
la sne, Ann. Sc. Nat. 3. xvii. 172, pi. 4. figs.
5-14 ; Schserer, JEhmm. crit. 85.

URCEOLARIA, Vuj.= Trichodma pt.
U. mitra= T. mifra.

URE'A. — This substance occurs normally
in the urine of man and the carnivora, in
small quantity in that of the herbivora ; also
in the amniotic liquid, and the vitreous and
aqueous humours of the eye. Pathologi-
cally, it is found in the blood, dropsical
effusions, vomited liquids, and doubtfully in
the saliva, the bile, and perspiration.

When pure, it forms colourless four-sided
prisms, sometimes longitudinally striated,
and with one or two oblique terminal facets.
The crystals are readily soluble in water and
alcohol, but not in pure ether.

When nitric or oxalic acid is added to a
solution of urea, the nitrate or oxalate sepa-
rates in the crystalline form.

The nitrate of urea, when rapidly formed,
consists of irregularly aggregated scaly crys-
tals (PL 13. fig. 18c); when more slowly
formed, rhombic or hexagonal plates, or
distinct prisms (fig. 18 #, ft). The crystals
of the nitrate of soda (PL 10. fig. 19) bear
some resemblance to those of the urea salt.

The crystals of the oxalate of urea some-
what resemble those of the nitrate, the
rhombic form being evident.

BIBL. That of CHEMISTRY, Animal.

UREDHSfE^E. — The genus Uredo is
shown by Tulasne to have no satisfactory
claim to a distinct existence, since the struc-
tures which have represented it appear to
be merely a form of the reproductive organs
common to a number of plants, which, in
their most perfect state, represent the genera
Puccinia, Phragmidium, Uromyces, &c.

TJREDINE^E.

[ 792 ]

UREDINE^E.

Fig. 773.

These constitute the genera of the family
Uredinei.

Of the genus Phragmidium, P. bulbosum
(Puccinia rubi, Schser.) is a species com-
monly occurring on the leaves of "brambles,
forming reddish, then orange, and finally
blackish rusty spots (fig. 773). The first
signs of reproductive organs appear in the
middle of the spots on the upper face of
the leaf, consisting of a few minute unilocu-
lar cavities (spermogonid) excavated in the
leaf, with a little flat ostiole ; in these
occur ovate sper-
matia (see JEci-
DIUM), which are
accompanied by a
yellowish mucous
liquid, and are ex-
pelled with this in
the form of drops.
Subsequently to
this, the Uredo-
fruits are deve-
loped, mostly on
the lower face of
the leaf, at the back
of the spermogonia,
or more rarely on
the upper face, in a
circle around them.
They are pulveru-
lent patches (fig.
773), solitary or a few together ; and a ver-
tical section (fig. 774) shows them to con-
sist of paraphyses (fig. 775), and simple or
branched short filaments bearing globose
stylospores (fig. 776), which soon become
detached, and in ripening acquire an echi-
nate outer coat with numerous pores.

Fig. 774.

Leaf of bramble,
" Uredo ruborum."
the nat. sfze.

with
Half

Vertical section of the same Uredo-fruit, with para-
physes and imperfect stylospores. Magn. 460 diams.

When these germinate, they produce merely
a long slightly branched filament. Finally
the perfect fruits (spores) appear on the
same, or in distinct son (on the lower ftice
of the leaf) in the form represented in fig.

Fig. 775.

Fig. 776.

Fig. 775. Separate paraphyses.
Fig. 776. Detached pedicels with stylospores.
Magnified 460 diameters.

Fig. 777.

Vertical section of the sorus of " Uredo suaveolens,'
with immature stylospores. Magnified 460 diameters.

Fig. 778.

Ripe stylospores of the same, germinating.
Magnified 460 diameters.

Fig. 779.

Fig. 780.

Deformed stylospores, with the spinulose coat deve-
loped. Magnified 460 diameters.

UREDINE^E.

[ 793 ]

URIC ACID.

565 (p. 594). The loculi of these have each
three or four pores in the upper part of the
side-walls, whence emerge in germination
(in spring) short tubular filaments, which
soon divide into four cells, from each of
which arises a minute " sporidium " borne
on a pointed sterigmatous process.

Puccinia composite rum exhibits very simi-
lar phenomena ; its Uredo-friut has been
described as Uredo suaveolens. Fig. 777
represents a vertical section through an im-
mature sorus of this ; fig. 778 some of the
stylospores detached and germinating ; the
Outer spinulose coat is here fully developed,
and the tubular filaments are seen emerging
from the pores. The spores of the perfect
f raits of this genus differ from those of
Phragmidium in being bilocular, or, by abor-
tion, unilocular (see PTJCCINIA).

In ^ECIDIIJM, CYSTOPUS, and some other
genera, spermogonia and stylosporous fruits
( Uredo-fruits, Tulasne) have been observed.
In Cronartium, spermogonia are unknown,
but the Uredo-h-uit exists. In Podisoma
both spermogonia and Uredo-fruits are un-
known ; in both of these genera the perfect
fruits are placed on a fleshy columella or
ligula.

We subjoin Tulasne's synopsis of the fa-
mily ; but as his generic characters are too
long to transcribe, the typical species only
can be cited.

I. Albuginei, white or pale yellow, hetero-

sporous.
Cystopus. Type, Uredo Candida.

II. &cidinei, with a peridium, homceo-

sporous.
Cceoma. Type, Uredo euonymi; U.

pinguis.
AZcidium, Type, jEc. cichoracearum •

JE. tussilaginis, JE. violarum.
Rcestelia. Type, sE. cancellation.
Peridermium. Type, Per. pint.

III. Melampsorei, solid, pulvinate, bif orm.
Melampsora. Type, Uredo populina ;

U. capreearum.

Cokosporium. Type, Uredo rhinantha-
cearum ; U. campanula.

IV. Phragmidiacei, pulverulent, biform,
infuscate ; centre of the family.

Phragmidium. Types, Phragmidium

incrassat.um, with Uredo ruborum ;

Puccinia potentilla, with Uredo poten-

tiUarum.

Triphragmium. Type, T. idmarice.
Puccinia. Type, Puccinia composita-

n>m, with Ur. suaveolens ; P.graminis,

with Ur. linearis.

Uromyces. Type, Uredo Jicarice.

Pileolaria = Uromyces ?, which itself
may consist of species of Puccinia
with spores unilocular by abortion.

V. Pucciniei, fleshy, ligulate, or tremel-

liform, naked and uniform in the

fruits ; the largest plants of the

family.
Podisoma. Type, P. juniperi commu-

nis.
Gymnosporangium. Type, P. junipe-

rinum.

VI. Cronartiei, peridiate, biform, ligulate ;
perhaps the most highly organized of
all the genera.

Cronartium. Type, Cr. asclepiadeum,
with Uredo vincetoxici j C. paonice,
with Ur.paonia.

Genera cancelled by Tulasne : — Uredo,
Epitea, Podocystis, Trichobasis, Lecythea,
Physonemttj Solenodonta.

Genera referred to USTILAGINEI : — Usti-
lago, TiUetia, Thecaphora.

Doubtful USTILAGINEI : — Protomyces, Po-
lycystis, Testicularia.

BIBL. Berk. Br. Fl. ii. pt. 2. arts. &cid.,
Puce., Uredo, $c. 5 Ann, N. H. i. 264, 2. v.
463 ; Tulasne, Ann. Sc. Nat. 3. vii. 12, 4. ii.
77; Le"veille, ib. 3. viii. 369; De Bary,
Brandpilze, 1853; Fries, Sum. Veg. 509;
Unger, Exanth. Plant. ; and the BIBL. of
the Genera.

URIC ACID and URATES, or lithic
acid and lithates. — Uric acid may easily be
procured in small quantities from human
urine, by adding a few drops of dilute mu-
riatic acid, and setting the liquid aside for
some hours, when it subsides in crystals.
In larger quantity it may be obtained by
heating the excrement of serpents with ex-
cess of dilute solution of potash, until the
odour of ammonia has disappeared, and fil-
tering the solution whilst hot into dilute
muriatic acid, when it falls in a colourless
state. Or the excrement may be digested,
without heat, with excess of strong sulphuric
acid, the mixture set aside that the impuri-
ties may subside, and subsequently poured
gradually into a large quantity of distilled
water.

It exists also in the excrement of birds,
in the urine of Mollusca and Insecta, and of
all the Mammalia, excepting those which
are herbivorous ; it has also been found in
the human blood, of which it is probably a
normal constituent in minute quantity, al-
though mostly secreted with the urine as
soon as formed.

URIC ACID.

[ 794 ] URINARY DEPOSITS.

In the natural state of solution in the
urine, uric acid exists combined with soda
and ammonia ; "but it is frequently found as
an abnormal deposit in the human urine,
and is often precipitated after the secretion
lias been evacuated, from the occurrence of
an acid fermentation. The crystals of the
free acid are sometimes also met with in
the urine or excrement of the lower ani-
mals, as Insects, &c.

Uric acid is l3ut little affected by water,
alcohol, acetic or muriatic acid, slowly so-
luble in solution of ammonia, but readily in
solution of potash, from which it is re-pre-
cipitated by a dilute acid.

The crystals belong to the right-rhombic
prismatic system.

Their various forms are represented in
PL 12. figs. 1-10, and fig. 1/5. Those in fig. 1
are frequently met with as natural deposits
from human urine, although most of the
same forms, with those in fig. 15, are also
found in the artificially precipitated acid.
The most common and characteristic form
is the rhomb («), the side view being linear
or rectangular. When the urine is strongly
acid, the crystals often appear striated from
the presence of linear fissures (c, d). Some-
times they are narrower and more elongate,
with a prismatic form (e). They are fre-
quently aggregated, and either fused into
twin crystals (/, #), or form aigrettes or
tufts (&, /, m, «, o). The other forms are
noticed in the description of the plate.

The crystals forming a natural deposit are
almost invariably^ coloured, from combining
with the colouring-matter of the urine ;
sometimes their colour is very brilliant
(fig. 4) ; they may also be coloured artifi-
cially by precipitation from a solution of
purpurate of ammonia (fig. 3), madder, &c.

The test for uric acid is the production of
the colour of purpurate of ammonia or mu-
rexide, which may be effected by dissolving
the crystals or suspected substance in a
small quantity of dilute nitric acid, gently
evaporating the solution to dryness, and
adding a little ammonia to the residue, or
exposing it to the vapour of ammonia, when
the red colour becomes visible. But the
rhombic form, when present, with the action
of potash and dilute acid, would be sufficient
to distinguish this acid from most sub-
stances.

The formation of the crystals of uric acid
presents an interesting object for examina-
tion. A drop or two of solution of uric acid
in potash is first placed upon a slide and

covered with thin glass ; a little dilute mu-
riatic acid is then applied to the edge of
the liquid, or a drop of strong acetic acid
placed near its edge, so that the vapour may
be absorbed by the liquid. The latter soon
becomes turbid, from the formation of a pre-
cipitate of numerous molecules and granules.
If the turbid liquid be watched under the
microscope, a minute crystal will presently
be seen to form suddenly in some part of
the field. The molecules and granules then
slowly dissolve immediately around the crys-
tal, leaving this in the middle of a clear
space. The crystal now enlarges, and the
surrounding molecules gradually disappear,
until they at last entirely vanish from the
field. By careful inspection, it may easily
be seen that the crystal is not formed by
the coalescence of the precipitated molecules,
but is deposited from a state of solution.

Some crystals of uric acid polarize light
splendidly ; and some of the feathery crystals
(Pi. 12. fig. 8 e) possess considerable ana-
lytic power.

The forms of the crystals and crystalline
groups of the urates are represented in PI.
12. figs. 11-14 ; they are not very charac-
teristic, and the aid of chemistry is required
for determining with certainty the com-
position of the respective crystals.

The urate of ammonia may be prepared
artificially by adding ammonia to a boiling
mixture of uric acid and water j the urate of
lime by mixing urate of potash with chloride
of calcium ; the urate of soda by dissolving
uric acid in solution of soda ; and the urate
of magnesia by mixing solutions of sulphate
of magnesia and urate of potash.

The presence of an excess of uric acid in
the blood is the chemical expression of
gout ; it leads to an abnormal precipitation
of urates in various parts of the body. In
cartilage the cells are the chief depositories
of the urates of soda and lime, and they form
the centres of the stellate bundles of crys-
tals by which the tissue is permeated.
The appearance of cartilage thus affected is
very characteristic ; and each cartilage cell
is surrounded by radiating tufts of crystals
which nearly or quite touch the extremities
of other groups radiating from neighbouring
cells. See URINARY DEPOSITS.

BIBI,. Rindfleisch, Path. Hist. ii. 270;
and that of CHEMISTRY, Animal.

URINARY DEPOSITS.— We shall give
here a list of the deposits most commonly
occurring in the human urine, with the re-
ferences to the plates in which they are

URINARY DEPOSITS. [ 795 ]

UROCOCCUS.

represented, and the articles in which they
are described.

Since the publication of the important
paper by Vigla (E Experience, 1839), in
which most of these deposits were first
illustrated, the use of the microscope has
constantly been called in to aid in their
detection. In regard to the pathological
indications afforded by their presence, upon
which we cannot enter, it may be remarked
that most of the deposits are* formed after
tlit- « vacuation of the urine.

Uric acid. PI. 12. figs. 1, 2; and Urates,
figs. 11 c, d, e, 13 a, 14 a (URic ACID and
URATES).

Oxalate of lime. PL 13. figs. 9, 10, 11,
12 (LIME, Salts of). The concretionary
forms of this salt (figs. 11, 12) are more
slowly acted upon by reagents than simple
crystals.

Ammonio-phosphate of magnesia, PI. 13.
figs. 1, 2, 3, 4 (MAGNESIA, Salts of).

Carbonate of lime. PI. 13. fig. 8 (LiME,
Salts of).

Cystic oxide. PI. 13. fig. 5 (CYSTIC
OXTDE).

Blood-corpuscles. PI. 49. fig. 21, espe-
cially the form fig. 21 e (BLOOD).

Mucous corpuscles. PL 1. fig. 6 (MotrTH,
p. 518).

Pus-corjw-sdes. PI. 38. figs. 4, 5 (Pus).

Spermatozoa. PL 50. fig. 25 (SPERMA-
TOZOA). These are found in the urine of
the female for several days after intercourse ;
and we have detected them in the uterus
more than a fortnight after the same.

Sarcina ? PL 7. fig. 5 (SARCINA).

Ftnn/f. Pcnmllium (fig. 557, page 584 ;
PL 26. fig. 15) and Torula (PL 26. fig. 7).
The spores of Penicittium form the so-called
small organic globules.

Casts of the tttluli v. rinifcri. The extreme
diameter of these is rather less than that of
the tubules ; but they are often much more
slender. They are* cylindrical, generally
wavy, sometimes hollow, at others solid.
Some are very transparent, finely granular,
and are composed of fibrine ; others consist
entirely of, or contain imbedded in them,
renal epithelial cells, with or without glo-
bules of fat either free or within the cells ;
they sometimes also contain mucous and
pus-corpuscles, with blood-globules; some
of the epithelial cells occasionally contain
lithates. The epithelium of the bladder
agrees essentially in structure with that
of the pelvis of the kidney.

BIBL. That of CHEMISTRY, Animal;

Hoppe-Seyler, Chim. phys. fyc. ; Schmidt,
Vermch. $c. ; Griffith, Urinary Deposits
and Med. Gaz. 1843.

URNATEL'LA, Leidy.— A genus of
freshwater Polyzoa.

Not yet found in Britain.

BIBL. Leidy, Pr. Ac. Philadelphia, v. &
vii. ; and Allman, Polyzoa, 117.

UR'NULA, Clap, et Lach.— A genus of
Actinophryina (Rhizopoda).

Char. Sheath membranous and fixed to
other bodies. U. Epistylidis (PL 52. fig. 15),
attached to the pedicle of Episti/lis plica-
tilts. (Clap, et Lach. Inf. 457.)

UROCENTRI'NA., A family of Ciliate
Infusoria.

BIBL. Clap, et Lach. Inf. 134.

UROCEN'TRUM, Nitzsch.— A genus of
Peritrichous Infusoria, family Urocentrina.

Cltar. Free, no pedicle j tail awl-shaped ;
cilia absent from the body, but forming an
anterior crown ; mouth not spiral.

U. turbo (PL 32. fig. 14). Body hyaline,
ovate, trilateral, tail one third the length of
the body. Freshwater ; length 1-430 to
1-290". (Cl. & Lachm. Inf. 134 ; Kent, Inf.
641.)

UROCOC'CUS, HassalL— A genus of
Palmellacese (Confervoid Alg8e),remarkable
for the peduncular processes formed by the
gelatinous coats of the cells. The cells are
invested by a gelatinous coat or membrane
(like that of GLCEOCAPSA), which is ori-
ginally simple ; but new gelatinous layers
are successively produced on the immediate
surface of the cell-contents ; and as each new
one is formed the preceding layer is rup-
tured on one side and partially thrown off,
the cell with its new layer lying in the pre-
ceding layer as in a cup ; by the repetition
of this process the cup-like exuviae accumu-
late, packed one within another so as to
form a peduncle, the structure of which may
be roughly compared to a pile of wooden
washing-bowls or tea-cups standing one in
another. When the cell-contents divide
into two portions, the peduncles bifurcate
(PL 7. fig. 7). The striae indicating the
successively shed coats are more or less di-
stinct in different species, and probably
in different conditions of the same. U.
flookwianus is represented in PL 7. fig. 7 ;
U. insiffnis is very much larger ; U. All-
ma mii and U. cryptophtia are much alike,
and neither presents the striae. A green
species is also described with the synonym
(erroneous ?) of Clilorococcum muralf, Grev.
Reproduction unknown.

TJROCYSTIS.

[ 796 ]

TJRQTRICHA.

BIBL. Hassall, Mar. Alg. 322, pi. 80;
Braun, Verjungung (Ray Soc. 1853, 178) ;
Rabenht. Alg. iii. 31.

UROCYS T1S. See POLYCYSTIS.

UROGLAUCINE. — This substance,
which was first detected by Heller, may be
obtained by evaporating human urine with
concentrated nitric acid (PL 13. fig. 20). Its
true nature is unknown ; but it is probably a
product of the decomposition of the colour-
ing-matter of the urine; it has perhaps
some relation with indigo.

BIBL. Heller, Archiv phys. Chemie und
Mikr. ; Lehmann, Phys. Chem. ; Funke,
Atlas.

UROGLE'NA, Ehr.— A supposed genus
of Volvocineae (Oonfervoid Algae), consist-
ing of a family of zoospore-like individuals
arranged at the periphery of a membranous
sphere, as in Volvox, but said to differ from
that genus in having only one cilium, and
a basal prolongation or tail running toward
the centre of the sphere. U. volvox forms a
sphere, 1-95" in diameter, with yellowish
bodies 1-1728" long, two lateral colour-
bands, exclusive of the tail, which is three
or four times as long. Inhabiting bog-pools.
Kent places it among the Flagellate In-
fusoria. (Ehr. Inf. 61: Kent, Inf. 414.)

UROLEPTUS, Ehr.— A genus of Hypo-
trichous Infusoria, family Colpodina ; fresh-
water.

Char. Eye-spot absent; no tongue-like
process or proboscis ; a tail present.

U. piscis (PI. 32. fig. 15 «) = Oxytricha
caudata, Duj. Body terete, subturbinate,
gradually narrowed behind into a tail ; in-
ternal granules green; length 1-288 to
1-144".

U. lamella (PI. 32. fig. 166). Body de-
pressed, hyaline, linear-lanceolate, flat and
very slender ; length 1-216". Other species.
(Ehrenberg, Inf. 358 ; Kent, Inf. 779.)

UROM'YCES, Lk.— A supposed genus
of Uredinei (Coniomycetous Fungi), perhaps
not properly separated from Puccinia, but
distinguished from the ordinary state of that
genus by the unilocular spores of the per-
fect fruit (see UREDINEI and PUCCINIA).
The genus Pileolaria, Cast., does not appear
to differ from Uromyces in any essential
particular. The Uromycetes are rusts oc-
curring upon leaves, presenting at least two
forms of fructification (spermogonia have
not yet been observed), viz. 1. Uredo-fruits,
consisting of stylospores unaccompanied by
paraphyses, which have been described as
species of Trichobasis, Lev. ; and 2. the per-

fect fruit, resembling that of PUCCINIA, but
with unilocular spores, unaccompanied by
paraphyses. U. fcarice. Lev. ( Uredofi-
carice, Alb. & Schw.) is not uncommon
on Ranunculaceae, U. appendiculatus, Lk.
(Uredo appendiculosa, Berk.), on various
Leguminosae.

BIBL. Berk. Br. Fl ii. pt. 2. 380, 382 ;
Tulasne, Ann. Sc. Nat. 4. ii. 145 & 185 ;
Leveille, ib. 3. viii. 370 ; De Bary, Brand-
pike, 33.

URONE'MA, Duj. -A genus of Holotri-
chous Infusoria.

U. marina (PI. 32. fig. 16). Body colour-
less, semitransparent, nodular, and with
four or five faint longitudinal ribs ; mouth
ventral, with a trap-like velum; marine;
length 1-570".

BIBL. Duj. Inf. 392; Clap. & Lach. Inf.
271 ; Kent, Inf. 546.

URONYCH'IA, Stein.— A genus of
Hypotrichous Infusoria. Oval-oblong, with
a carapace, truncate in front, with a mem-
branous upper lip, with posterior hooks ;
mouth excavated, with a band-shaped un-
dulating membrane.

U. transfuga=Plcesconia scutum, Duj.
Salt water. (Stein, Inf. ; Kent, Inf. 797.)

UROP'ODA, Latr.— A genus of Arach-
nida, of the order Acarina and family Ga-
masea.

Char. Palpi and rostrum inferior ; dorsal
shield consisting of a single, broad, circular
or oval piece ; legs nearly equal ; body fre-
quently with a caducous anal peduncle.

U. vegetans (PI. 6. fig. 25). Sixth joint
of legs longest. The peduncle forms a
horny filament, secreted rrom the anus, and
serving to attach the body to Coleopterous
insects, of which this animal is the parasite,
although it is sometimes found under
stones. Four other species, most of them
doubtful.

BIBL. Duges, Ann. Sc. Nat. 2. ii. 29;
Gervais, Walck. Apt. 220.

UROSTY'LA, Ehr.— A genus of Hypo-
trichous Infusoria, fam. Oxy trichina.

Char. Body ciliated ; styles present in a
small cleft on the ventral surface ; no hooks.

U. grandis (PI. 32. fig. 17). Semicylin-
drical, subclavate, rounded at the ends,
slightly thickened in front; freshwater;
length 1-44 to 1-96". (Ehr. Inf. 369;
01. & L. Inf. 142 ; Kent, Inf. 797.)

UROT'RICHA, 01. & Lachm.— A genus
of Holotrichous Infusoria, family Trache-
lina. Free, ovate, with a long posterior
saltatory cirrus.

UKTICA.

[ 797 ]

USTILAGO.

Two species j freshwater. (Cl. & Lachm.
Inf. 314; Kent, Inf. 504.)

URTI'CA, L.— A genus to which the
.-tinging-nettle belongs (see STINGS).

US'NEA, Ach. — A genus of Bamalodei
(Lichenaceous Lichens), with a somewhat
crustaceous branched thallus, bearing pel-
tate apothecia, which often have a ciliated
margin. U. barbata is common on park-
pales and old trees, U.florida vo&fiKeata in
similar situations, mostly in mountainous
regions. The pendulous fibrillous thallus
and ciliated apothecia of U. barbata are
very characteristic.

BIBL. Hook. Br. FL ii. pt. 1. 230; Leigh-
ton, Lich. FL 75.

USTILAGIN EM.— A family of Hypo-
dermous Fungi related to the Urediuei,
generally distinguished by their growing in
the interior of the organs (especially the
ovaries and anthers) of Flowering Plants,
causing deformity, absorption of the internal
tissue, and its replacement by a pulverulent
substance consisting of the" spores of the
Fungi. In the earlier stages, the infected
organ exhibits either a grumous mass, or
an interwoven filamentous mycelium, from
which acrogenous spores arise ; finally the
mycelium disappears, and a dark-coloured
(often foetid) powder remains, composed
entirely of the spores, which are simple, or

Fig. 781. Fig. 782.

Fig. 783.

Fig. 784.

Fig. 785.

Thecaphora deformans.

Compound spores, entire and broken up.

Magnified 460 diameters.

more rarely compound (figs. 784, 785), i. e.
several coherent within a common coat, at
length free (figs. 781-783), smooth or
unequally echinate or reticulated.

BIBL. Berk. Br. Fl, (art. Uredo) ; Tulasne,
Ann. So. Nat. 3. vii. 5, ii. 157 ; De Bary,
Brandpilze; Bauer and Banks, Cttrtis's

Pract. Obs. on Br. Grasses, 1805; Unger,
Exanthem. Plant. ; Fischer v. Waldlieim,

Ustilaf/mt'i.

USTILA'GO, Fries.-
laginei (Hypodermous

Fig. 786.

-A genus of Usti-
Fungi), forming

Fig. 787.

Fig. 786. Ustilago Carbo, on oats. Nat. size.
Fig. 787. Ustilago Carbo, on barley. Nat. size.

smuts, infesting the ears of corn and other
grasses, the ovaries and anthers of other
Flowering Plants, and in some cases the
leaves and stems of plants. The interior of
the organ infested by them presents at
first a grumous-mucous whitish mass, which
grows at the expense of the tissue and juice
of the infested organ, and is finally con-
verted into a pulverulent mass of simple
spores, mostly of deep colour, and with a
smooth, spiny or reticulated surface.

The species growing upon leaves and
stems occur on grasses, e. g. U. longissima
( Uredo longissima, Sow.), U. hypodytes ( Ur.
hypodytes}, and U. grandis (or typhoides) ;
they form linear patches, ultimately con-
taining smooth black spores.

The greater number, however, occur in
the parts of flowers, especially of grasses —
Ust. Carbo (Uredo segetum, Pers.), form-
ing the blight called smut of corn, com-
monly infesting wheat, oats (fig. 786), barley
(fig. 787), and other grasses, filling the ears
with a black powder of smooth spores,
about 1-5000" in diameter in corn, some-
times about twice as large in the varieties
attacking species of Bromus. The smut of

UTERIA.

[ 798 ]

UVELLA.

maize (U. maidis, fig. 788) has minutely
echinate spores, 1-2500" in diameter.

It is curious that when U. Anthe-
rarum attacks a dioecious plant, as Lychnis
dioica, it causes the abortive stamens to be
developed, and then finds its place in the
new anthers.

Sedges are infested by Ust. wceolarum
with dark-brown and Ust. olivacea with
olive-coloured spores (Uredines, Br. Fl.)

Fig. 788.

Portion of a spike of Maize infested with Ustilago
maidis. Some of the lower grains perfect and mature :
above these, female flower with abortive ovaries. The
projecting bodies are grains which have become de-
formed by the Ustilago developed within them.

Ust. antherarum, growing in the anthers of
Caryophyllacese, has violet-coloured spores.
Many other species are described by Tulasne,
several of which have occurred in Britain.

BIBL. Tulasne, Ann. So. Nat. 3. vii. 73, 4.
ii. Io7 ; Berk. Br. Fl. art. Uredo; Ann. N.
H. 2. v. 463.

TJTE'RIA, Mich. See THYRSOPOBKLLA.

U'TERUS.— The substance of the uterus
consists of longitudinal, transverse, and

Fig. 789.

oblique unstriated muscular fibres, inter-
woven with imperfectly developed areolar
tissue resembling that in the stronia of the
ovary.

Three layers of muscular fibres are de-
scribed, but they are intimately connected.
Those in the cervix are principally trans-
verse or circular ; and immediately beneath
the mucous membrane at the mouth of
the uterus, the transverse fibres form, a
sphincter.

The muscular fibres are
from 1-COO to 1-400" in
length, fusiform, with elon-
gate-oval nuclei, and very
difficultly separable on ac-
count of the large amount of
areolar tissue intermingled
with them.

The epitheliumis simple
and ciliated. The mucous
membrane of the body has
no papillae, but hero and
there some folds, and con-
tains numerous tubular or
uterine glands resembling
the Lieberkiihn's glands of
the intestines, their caecal
ends being simple, bifurcate,
or spiral, and consisting ^ of
a basement-membrane with
cylinder-epithelium. ^

In the cervix are situated
glandular depressions of the
mucous membrane, which
secrete a transparent tena- after parturition,
cious mucus ; some of these S^J^Sjf?
are closed, and form the y, globules of fat.

OVUles Of Naboth. Magnified

The lower third or half 350 diameters,
of the canal of the cervix
contains papilla covered with ciliated epi-
thelium.

During gestation the uterine elements,
especially the muscular fibres, as also the
vessels and probably the nerves, become
enlarged and more numerous, from new
formation (fig. 790).

All three of the coats of the veins of the
pregnant uterus contain muscular fibres.
After parturition, many of the muscular
fibres undergo fatty degeneration, and be-
come absorbed (fig. 789).

BIBL. Kblliker, Mikr. An. ii. ; Chrobak,
Strieker's Hist. iii.

UVEL'LA, Bory, Ehr.— A genus of
Flagellate Infusoria, fain. Monadina.

Char. Bodies without an eye-spot,

UVELLA.

Fig. 790.

[ 799 ]

VALLISNEEIA.

Muscular elements from a uterus at five months' ges-
tation, a, formative cells ; b, young, c, fully developed
muscular fibres. Magnified &30 diameters.

moving by means of two flagelliform fila-
ments, and aggregated into spherical revol-
ving clusters.

U. virescens (PI. 32. fig. 18). Bodies
ovate, rounded at each end, with two lateral
bright green bands. Diameter of clusters
1-288", length of bodies 1-2016" ; fresh-
water.

The life-cycle of a cercomonad. — One of
the Uvelke has been described by Dallinger
and Drysdale. When mature it multiplies
by fission for a period extending over from
two to eight days. It then becomes pecu-
liarly amoeboid ; two individuals coalesce,
slowly increase in size, and become a slightly
distended cyst. The cyst bursts, and incal-
culable hosts of excessively minute sporules
are poured out, as if in a viscid fluid and
densely packed; these are scattered, and
slowly enlarging, acquire flagella. Thev be-
come active, attain rapidly the parent form,
and once more increase by fission.

BIBL. Dallinger and Drysdale, Mn. Mic.
Jn. 187:;; Ehr. Inf. 19; Duj. Inf. 300;
Kent, Inf. 400.

< UVIGERrNA D'Orb.— A genus of hya-
line Foramiuifera, near Polymorphina. Shell
made up of tliree series of inflated chambers,
alternating irregularly on an elongate spire,
often ribbed ; orifice central, round, tubular,
and lipped. The triserial alternation passes
sometimes into a biserial and even a uni-
serial growth (Sagrina, restricted). Uviye-
rina is world- wide in its distribution, and
goes back to the Middle Tertiary Period.
U. pygmaa (PI. 23. fig. 8).
BIBL. D'Orbigny, Ann. Sc. Nat. vii. 269 ;
Carpenter, For. 1C9 ; Parker & Jones, Phil.
Tr. civ. 363.

V.

VAGINIC'OLA, Lamarck.— A genus
of Peritrichous Infusoria, fam. Vorticellina.

Char. Bodies as in Vorticella, single or
in pairs, in a membranous urceolate sessile
sheath.

V. crystallina (PI. 32. fig. 19) = Cothurnia
crystalline Sheath crystalline, urceolate,
straight, internal granules erreen ; length
1-216".

Several species, salt and freshwater.

BIBL. Ehr. Inf. 295 ; Clap. & Lach. Inf.
126.

VAGINULI'NA, D'Orb.— A Stichoste-
gian subgenus of Nodosarina, with oblique
chambers.

V. ladenemis, D'Orb. (PL 23. fig. 35).

BIBL. Williamson, Foram. 21 (Dentalma) ;
Jones, Parker, and Brady, Monogr. For.
Crag, 63.

VALKE'RIA, Flem.— A genus of In-
fundibulate Ctenostoniatous Polyzoa, of the
family Vesiculariidse.

Char. Variously branched; cells oval,
irregularly clustered; eight tentacles, but
no gizzard.

V. cuscuta. Stem with subverticillate
branches ; cells in clusters or opposite pairs ;
on marine Algse, shells &c.

V. uva. Stem creeping, irregularly
branched ; cells scattered.

V.ptutxdota. Dichotomous or alternately
branched ; cells clustered, unilateral.

V. tremella. Cells very small and slender.

BIBL. Johnst. Br. Zooph. 373; Gosse,
Mar. Zool. ii. 20; Hincks, Polyz. 551.

VALLISNE'RIA, Mich.— An aquatic
genus of Angiosperrnous Flowering Plants,
belonging to the family Hydrocharidacese.
V. spiral-is, a native of the South of Europe,
occurring wild also in North America, India,
&c., is commonly grown in jars for the sake

VALVULINA.

[ 800 ] VASCULAR BUNDLES.

of observing the ROTATION in the leaves.
This plant is dioecious ; and the specimens
ordinarily found in cultivation are the pistil-
late forms, which often produce flowers,
but the seeds, remaining unfertilized, never
ripen j the plant increases rapidly, however,
by runners, if in a healthy condition. We
find it thrive well in any situation indoors
near a window and not exposed to frost ; but
it attains a far larger size in water kept at a
high temperature, as in Fzetfona-tanks in
Botanic Gardens. It is necessary, when
STpwing it in jars, not to keep too many or
too large snails in the water, as they destroy
the leaves. See ROTATION.

VALVULI'NA,D'Orb.— A genus of Are-
naceous Foraminifera.

Typically it has a triserial, three-sided,
pyramidal shell, with three chambers in a
turn of its spire and a valved or tongued
aperture. The trifacial compression disap-
pears in a common trochoid form, which
becomes scale-like and flat. If the cham-
bers fail to make a coil, an obliquely semi-
oval shell is produced, with a broad oblique
septal plane and a large valve, which bridges
over the crescentic aperture with bars. The
triangular form sometimes becomes Bulimi-
noid ; and often takes on a uniserial growth
(Clavulina, restricted), either cylindric, tri-
carinate, or five-angled. Numerous forms,
recent and fossil. V. austriaca (PI. 23. f. 20).

BIBL. Parker & Jones, Ann. N. H. 3. v.
467 ; Carpenter, Foram. 146 j Brady, Carb.
For., Pal. Soc. 1876, 81.

VAMPYREL'LA, Hckl.— A doubtful
genus of Radiolarian Rhizopoda. Body
red, rounded, without nucleus or contractile
vesicle, and with very slender pseudopodia.
These animals perforate the cells of Spi-
rogyra and Gompkonema,&nd feed upon their
contents. In the encysted condition, they
are stated to possess an outer nitrogenous
and an inner cellulose coat.

BIBL. Haeckel, Qu. Mic. Jn. 1869, 33 ;
Schnitzel Arch. 1876, xii. 24.

VARIOLA'RIA,Pers. — A spurious genus
of Lichens, founded upon imperfect forms
of PERTUSARIA &c.

BIBL. Hook. Br. Fl. ii. pt. 1. 172 ; Schae-
rer, En. Grit. 229.

VASCULAR BUNDLES.— This title is
applied to the fibrous cords which form the
ribs, veins, &c. of the leaves, petioles and
other appendicular organs of all plants rank-
ing above the Mosses, and which by their
confluence and more considerable develop-
ment constitute the wood of stems and

trunks. The vascular bundles of petioles
(fig. 660, page 711), &c., running into leaves
to form their ribs, and lying imbedded in
parenchyma, resemble the bundles which
form the rudiments of wood of the stem
itself. The bundlesremain isolated as fibrous
cords in the stemsof the herbaceous Monoco-
tyledons, or are only combined into a wood,
in the Palms &c., by the lignification of the
cells of the parenchyma in which they are
imbedded (fig. 461, p. 508).

In the Dicotyledons, the rudimentary
bundles are developed in a circle surrounding
the pith (fig. 455, p. 495), and soon unite
to form a tube of wood, with an external
cambium layer and a true bark j and the

Fig. 791.

Monocotyledon.

Transverse section of a nbro-vascular bundle of a
Palm : the upper end is directed towards the centre of
the stem, w, woody fibres resembling liber in struc-
ture ; s. v, spiral vessels ; c, cambium (vasa propria) ;
d, ducts ; p, parenchyma ; /, liber ; I. c, laticiferous
canals. Magnified 150 diameters.

cambium layer is the seat of renewed de-
velopment of the vascular bundle in each
successive year. On such characters of
growth, Schleiden founded a division of the
vascular bundles into classes which are con-
venient in reference to microscopical inves-
tigations, and affixed tolerably perfect syste-
matic characters to them.

In the higher flowerless Plants, viz.
Ferns, Equisetacese, &c., the vascular bun-
dles ate composed chiefly of ducts, sur-

VASCULAR BUNDLES. [ 801 ] VASCULAR BUNDLES.

rounded by elongated tubular cells, almost
devoid of secondary deposits, the whole
enclosed by a layer of tolerably firm prosen-
chymatous wood-cells, especially developed
in the Ferns. In the Ferns, the ducts are
mostly of the kind called scalariform (fig.
664, page 712 j PI. 48. fig. 10), in the Equi-
setacec'e annular (fig. 661, page 711), in the
Lycopodiacese spiral (fig. 659, page 711 ;
PI. 48. figs. 11 & 12). They are variously
arranged in the different orders, but agree in
the mode of development, namely in grow-
ing only at the end next the punctum vege-
tationi*, in proportion to the elongation of
the stem and the evolution of leaves. Hence
Schleiden called them simultaneous bundles ;
their various elements — ducts, tubular and
prosenchymatous cells — being formed si-
multaneously.

In the Monocotyledons, where the vas-
cular bundles occur isolated, they originate
in the punctum vegetationis, and are deve-
loped with the growth of the stem, outwards
and upwards into the leaves, and outwards
and downwards towards the permanent cir-
cumference of the stem, old and new bundles
crossing each other in a more or less com-
plicated manner (fig. 461, page 508). Here
(fig. 791) the first trace of the vascular bundle
consists of spiral vessels, followed on the
outer side by spiral, annular, or reticulated
ducts 5 next comes a collection of elongated
tubular cells of delicate structure (vasa
proprid), and in the outer part, at first, a
cambium region, which is gradually con-
verted into prosenchymatous woody struc-
ture having the character of LiBER-cells.
In this case, the development is not only
gradual from the punctum vegetationis out-
ward, but the inner side of each bundle is
perfected first, and the conversion of the
outer part into wood occupies a whole
season of growth. Hence these are entitled
progressive bundles ; but as no new develop-
ment occurs in these in successive seasons,
they are further distinguished from those of
the Dicotyledons as definite bundles. The
structure of the vascular bundles of Monoco-
tyledons is very well seen, indifferent charac-
teristic conditions, in vertical and horizontal
sections of the stems of the white lily, of the
large grasses,rhizomes of sedges and rushes —
affording well-developed examples in herba-
ceous structures ; of the bamboo (an arbo-
rescent grass), of the common cane or the
partridge cane (both species of Palms),
where the bundles are connected by lignified
parenchyma* In leaves of bulbous Monoco-

tyledons, &c., the bundles consist chiefly of
spiral vessels ; in the palms, bananas, &c.,
the woody fibre extends also into the ribs of
the foliaceous organs.

In the Dicotyledons, the bundles of the
stem appear first as a circle of cords com-
posed or spiral vessels, around the pith, out-
side whicn larger vessels and ducts, and
subsequently woody fibre or wood-cells are
developed, passing into the elongated pros-
enchymatous liber (fig. 792). The develop-

' Fig. 792.

Dicotyledon.

Transverse section of a flbro-vascular bundle of a
Melon stem ; the upper end next the centre of the stem.
p, pith ; s. v, spiral vessels ; TO. r, medullary rays ; w,
wood ; d, pitted ducts ; c, cambium ; I, liber ; I. c, lati-
ciferous canals; c. e, cellular envelope of the bark; e,
epidermis. Magnified 50 diameters.

ment of the successive regions is progressive
during the first season ; but here the cam-
bium layer remains capable of renewed
activity, and a new layer of wood (and of
liber) is added on the outside of the bundle
in each successive season j hence these bun-
dles are distinguished as indefinite. These
may be observed in sections and young
shoots of any common tree (figs. 455 & 457,
pages 495 & 496).

Infinite variety of modification occurs in
the character and arrangement of the vas-
cular bundles within the limits above laid
down, or very slightly overstepping them.
A few remarkable cases may be mentioned
here ; in the Orobanchaceae (parasites) no
spiral vessels occur in the vascular bundles
forming the wood; in Victoria regia the
isolated bundles are composed of spiral
vessels without any prosenchymatous wood-
cells j other peculiarities, influencing more

VASICOLA.

[ 802 ]

VAUCHERIA.

especially the characters of WOOD, are given
under that article. Vasculose, the sub-
stance of which vessels are formed, is in-
soluble in hydrochloric and sulphuric acid,
and in copper solution, but is soluble in
boiling caustic potash. (See also CAMBIUM
and MEDULLA.)

BIBL. Henfrey-Masters, J3ot.-, Sachs,
Bot.

VASIC'OLA,Tatem.— AgenusofHetero-
trichous Infusoria. Ovate, pointed behind ;
mouth anterior, surrounded by long cilia;
contained in a transparent carapace.

V. ciliata-, pond- water. (Tatem, Mn.
Mic. Jn. i. 117 j Kent, Inf. 613.)

VAUCHE'EIA,D.O.— An important and
to the microscopist a most interesting genus
of Siphonacese (Oonfervoid Algas), consisting
of green filamentous plants growing in fresh
and salt water and on damp ground, charac-
terized by the continuity of the cavity
throughout the branched tubular filament
(sometimes several inches long) of which
each plant is composed, and by the modes of
reproduction, both by gonidia and by spores.
FrtwcAmVemaybe gathered on damp borders
in every garden, or by the sides of ditches,
where they form fine silky green tufts ; they
are very variable in form and size, so that
the specific distinctions heretofore laid down
appear to be worth little. The ordinarily
occurring species presents itself as a tubular
cell of comparatively gigantic dimensions,
containing more or less protoplasm, coloured
by chlorophyll in the form of minute gra-
nules applied upon the wall or occupying
more or less of the cavity. The green gra-
nules may be seen to lie imbedded in a
colourless protoplasm at the inner surface
of the cellulose wall ; and it is curious to
observe when the filament is accidentally
or intentionally ruptured that the green
granules which may escape are contained in
a mucous investment, wnich soon rounds
itself into a globular body, of size propor-
tionate to the quantity of green granules
extruded ; these globules sometimes even
exhibit a slight rolling movement, but they
appear ultimately to decay. Such globules
sometimes occur inside the filaments, when
the growth is unhealthy; and Itzigsohn calls
them spermatospheres, stating that they pro-
duce spermatozoids. This, like all this au-
thor's observations, requires confirmation.

If the Fawc^ma-filaments are gathered at
a favourable epoch, or if they are cultivated
in a vessel of water well exposed to light,
the blind ends of the filaments (or rather of

the ramifications of the filament) are found
very ^ densely filled with green contents, ap-
pearing almost black ; and if these ends are
watched early in the morning, a remarkable
series of phenomena is observed in them.
The ends of the filaments about to produce
gonidia are found swollen into a slightly
clavate form ; the green contents of the club
separate from the general contents of the
filament, leaving a transparent space (fig.
793) ; then, having as it were acquired
a definite independence, the isolated mass
returns so as to fill up the transverse light
space, but does not again coalesce with the
lower mass of contents. Next, a light space
is ^observed between the surface of the ter-
minal body of contents and the cellulose

Fig. 793.

Fig. 794.

Vaucheria Ungeri.

Fig.- 793. End of a filament in which a gonidium is
being developed.
Fig. 794. GFonidium escaping from the filament.

Magnified 50 diameters.

wall surrounding it ; and the latter soon
gives away at the apex, forming a passage
for the escape of the contents. This mass
of contents is now clearly recognizable as the
gonidium or zoospore ; it gradually extri-
cates itself from the tube, with a rotatory
motion around its own axis ; and it exhibits
a remarkable elasticity of structure, giving
way and altering its form (fig. 794) to
squeeze through the narrow orifice of es-
cape. Sometimes it becomes "pinched " in
this process into two independent gonidia
of half the usual size. As soon as it has
perfectly emerged, it assumes an elliptical
form, increases much in size, and is seen to
be covered with innumerable vibratile cilia
(fig. 796), arising from its gelatinous (pro-
toplasmic) coat (these are rendered much
more distinct by applying tincture of

VAUCHERIA.

[ 803 ]

VAUCHERIA.

iodine) : no cellulose membrane exists at
this time ; and the gonidium swims about
actively inth e water, revolving on its long
axis. The large number of cilia existing on

Fig, 795.

Fig. 796.

Vaucheria Ungeri.

Pig. 795. End of the filament from which the gonidium
has escaped. Magnified 50 diameters.

Pig. 796. G-onidium which has been treated with
iodine and dried between two slips of glass, showing
the cilia very clearly. Magnified 110 diameters.

this gonidium distinguish it remarkably
from all others ; but we are inclined to be-
lieve that there is a nearer relationship than
appears at first sight. The green substance
at the surface of the gonidium presents a
peculiar granular or globular appearance;
and it appears not far-fetched to regard this
body as composed of a densely combined
family of ordinary two- or four-ciliated
zoospores, such as would be formed by the
swarrning-spores of Hydrodictyon if they
remained in their primitive crowded con-
dition. This, however, is a point requiring
further examination. The end of the tube
from which the gonidium has escaped ap-
pears as a hyaline sac (fig. 795), which soon
decays down to the point where the con-
tents parted, where a septuni, now closing
the tuoe, is developed.

After swimming about for some time,
from one to several hours (usually about
two), the gonidium falls to the bottom of
the vessel, its cilia disappear, and it assumes
a spherical form, acquiring very soon a di-
stinct cellulose coat ; after this it soon ger-
minates by pushing out one or more tubular
processes (fig. 797), which grow up into
filaments like the parent. Sometimes the
gonidium cannot maKe its escape ; sometimes
half of it escapes and becomes pinched off,
the other half being left behind : in these
cases, the arrested body, or the remaining
portion of the divided one, germinates in
situ (fig. 798).

It should be mentioned that the contents

of the vegetative filaments have a remark-
able tenacity of life ; for if the tube is slightly

Fig. 797.

Fig. 798.

Vaucheria Ungeri.

Pig. 797. Gronidia germinating. Magnified about 15
diameters.

Fig. 798. Filament with gonidia germinating in the
parent tube ; the left-hand figure, half a divided goni-
dium. Magnified 25 diameters.

injured at any point, the primordial utricle
commonly retracts from the wound, and
secretes a cellulose layer on its surface,
shutting off the injured part. Filaments
are sometimes met with having several
living regions of this kind, shooting out
into branches, separated from each other
by dead, empty lengths of the filament.

Besides the vegetative reproduction above
described, the Vaucherice are reproduced by

rres formed by the concurrence of two
tinct kinds of reproductive organs. Fila-
ments growing on damp ground ordinarily
exhibit lateral organs of two kinds, asso-
ciated together, but variously grouped and
collected in varying numbers at particular
points, apparently according to external
conditions. The larger kind of organ, or
sporangium, appears first as a pouch-like
process, which expands into a short flask-
shaped body, stalked or sessile, the neck of
which is gradually turned over in the
development, until it projects at one side j
the form then somewhat resembling that of
a bird's head (or a chemist's glass retort cut
off short at the neck, PI. 5. fig. 12 A, B, s).
Near this, on the main filament, or on a
common pedicel with one or more of the spo-
rangia, is developed another organ, the an-
theridium, at first straight and tubular, but
soon curving over into the form of a hook or
scroll, without however expanding (PI. 5.
fig. 12 A, B, a). The sporangium becomes
filled with dense green granular matter, and
cut off by a septum from the main filament.
3F2

VEGETABLE IVORY. [ 804 ] VEGETABLE KINGDOM.

The upper part of the antheridium is like-
wise cut on by a septum ; and when mature
it bursts at the apex and discharges biciliated
spermatozoids resembling those of Pucus,
which enter the simultaneously opened neck
of the sporange and fertilize its granular
contents. The contents become isolated
from the wall, secrete a proper coat, and
form a free cell (spore) lying in the sporange,
its green granular matter gradually becoming
brown (PI. 5. fig. 12 c). Two coats, at least,
are developed ; and the spore ultimately
escapes by the decay of the parent filament
and sporange. According to Pringsheim,
about three months elapse before germina^
tion, in which process the outer spore-coat
splits, and the inner grows out into a
tube, forming the basis of a new ramifica-
tion of the F<mcAma-filainent.

In the systematic works on Algology,
numerous species of aquatic and land Vau-
cherifs are described ; but we agree with
Thuret in believing that the characters by
which most of the forms are distinguished
are unessential, therefore we omit any syn-
opsis of them. Even V. racemosa, De-
caisne, appears merely an extreme of the
kind of development producing V. geminata.
Thuret proposes the name V. Ungeri, to in-
clude all but V. racemosa j Hassall suppresses
the name V. clavata, as indicating a form
common to all the species, of which he de-
scribes a large number. We do not find
any thing sufficiently distinctive in the cha-
racters of the marine species cited by
Harvey.

BIBL. Vaucher, Conserves cfeau douce
(Ectosperma) ; Hassall, Alg. j Harvey, Mar.
Alg. 195; linger, Nova Acta, xiii. 11, Die
Pflanze im Mom. der Thierwerdung , 1843 j
Decaisne,^4ww. Sc. Nat. 2. xvii. 430 ; Thuret,
ibid. xix. 266 ; Karsten, Bot. Zeit. x. 85, xv.
1 ; Pringsh. Ber. Berl. Ak. 1855 ; Ann. N.
H. 2. xv. 346 ; Braun, Verjung. (Ray Soc.),
Alg. unicell., 8, 105 ; Nageli, Neues Algen-
syst. 175, pi. 4; Itzigsohn, Bot. Zeit. xi.
225 ; Dippel, Flora, 1856, 481 ; Rabenht.
Alg. iii. 267 j Sachs, Bot. 275.

VEGETABLE IVORY.— This substance
consists of the seeds of the Palm called
Phytelephas macrocarpa, and is composed of
a large round mass of bony ALBUMEN, in
which a small embryo is imbedded. Slices
of^this ivory-like albumen, placed under the
microscope, afford very beautiful examples
of vegetable cells with the cavities almost
obliterated by SECONDARY DEPOSITS (PL
47. fig. 23).

VEGETABLE KINGDOM.— The large
number of Natural Orders of Angiospermous
Flowering Plants, and the subordinate
characters of their diversities in microscopic
structure, lead us to depart from the plan
on which^ the Synopsis of the Animal
Kingdom is given and carry it into effect
here only in reference to the Cryptogamic
plants. For the microscopic phenomena in
the Phanerogamia described in this work,
reference should be made to the articles
EMBRYO, OVULE, TISSUES, WOOD, &c.

Kingdom VEGETABILIA.
Subk. 1. Phanerogamia. Flowering plants .
Division 1. Angiospermia.
Class I. DICOTYLEDONS.

Most common trees and herbs.
Class II. MONOCOTYLEDONS.
Grasses, rushes, most bulbous plants,

palms, &c.

Division 2. Gymnospermia.
Class III. CONIFERS.

Firs, pines, yew.
Class IV. CYCADACE^:.
Cycas, Zamia.

Subk. 2. Cryptogamia. Flowerless plants.
Division 1. Cormophytes or Acrogens.
Class I. LYCOPODIALES.
Order 1. MARSILEACEJE.

Pilularia, Pill-wort.
Order 2. LYCOPODIACEJE,

Club-mosses.
Class H. FILICALES.
Order 1. FILICACEJE.

Ferns.
Order 2. EQUISETACE^E.

Horse-tails.
Class III. MUSCALES.
Order 1. MUSCACE.ZE.

Mosses.
Order 2. HEPATICJE.

Liverworts and Scale-Mosses.
(Order of uncertain place, CHA-

RACEJE.)

Division 2. Thallophytes.
Class I. AJLGM.
Order 1. FLORIDEJE.

Red sea-weeds.
Order 2. FUCOIDE^E.
Olive sea-weeds.
(Phaeosporese.)
Order 3. CONFERVOIDE^E.

Green silk-weeds, slime-weeds,
and brittle-weed8(Diatomacea3).

VEINS.

[ 806 ]

VERRUCARIA,

Class II. LICHENS.
Class III. FUNGI.

Order 1. SCHIZOMYCETES.

Bacterium, Vibrio.
Order 2. PHYCOMYCETES.

Moulds and mildews.
Order 3. HYPODERMIC.

Uredinese, Ustilaginese, smuts, &c.
Order 4. BASIDIOMYCETES.

Mushrooms, toad-stools, puif-balls.
Order 5. ASCOMYCETES.

Truffles, inorells, &c.
Order 6. MYXOMYCETES.

Trichia, JEthalium, Lycogala.

BIBL. Lindley, Veg. Kingdom-, End-
licher, Gen. Plant. ; Fries, Summa Veget.
Scan.-, Henfrey-Masters, JElem. Course',
Sachs, Lehrb. Bot.

VEINS OF ANIMALS.— The walls of the
veins are thinner than those of the arteries,
which arises principally from the less de-
velopment of the contractile and elastic
elements. The inner coat is less developed,
but otherwise agrees with that of the arteries
in structure. The middle coat is not yellow,

Fig. 799.

Longitudinal section of the vena cava inferior, near
the liver, a, inner coat ; b, middle coat without mus-
cular fibres ; c, inner layer of the outer coat — a, its
longitudinal muscles; j8, its transverse areolar ele-
ments; d, outer portion of the outer coat, without
muscles. Magnified 30 diameters.

but greyish red, containing more connective
tissue and fewer elastic fibres and muscles ;
in addition to the transverse, it has longitu-
dinal layers. The outer coat is usually the
thickest, agreeing with that of the arteries,
except that in many veins, especially those
of the abdominal cavity, it contains well-
developed longitudinal muscular fibres.

The veins of the brain, the bones, retina,
&c., contain no muscular fibres.

The large veins, near the heart, contain
transverse striated muscular fibres.

BIBL. Kolliker, JKrt.ii.; Eberth,$nc&?r'«
Hist. ; Frey, Hist.

VEINS OF PLANTS. — The name com-
monly applied to the ramifications of the
VASCULAR BUNDLES, forming the ribs of
leaves and similar organs.

VENILI'NA, Giimbel. SeeTsxTULARiA.
(Giimbel, Tr. Munich Acad. cl. 2. x. 648).

VERMES.— A subkingdom of the ANI-
MAL KINGDOM.

VERMICULA'RIA, Fr.— A genus of
Sphseronemei (Coniomycetous Fungi), but
seemingly stylosporous states of Sphseriacei,
most of the species being included under
Sphesria in the British Flora. They grow
on decaying stalks, leaves, or wood. S. re-
licina, t)ematium, culmifraga, trichella, and
others of the Br. Fl. belong here. Another
species, V. atramentwia, is common on de-
caying potato-stems, forming black velvety
patches. This is distinguished from V.
Dematium by its straight spores. The erect
black hairs of the perithecia are character-
istic.

BIBL. Berk. Br. Flor. ii. pt. 2. 274, &c.,
Ann. N. H. 2 v. 378; Fries, Sum. Veg.
419.

VERMILION, or bisulphuret of mercury,
is used as a pigment for inj ecting. It should
be in a finely divided state, in which it is
best obtained by levigation, and should not
exhibit any white crystalline particles when
examined as an opaque obiect.

VERNEUILI'NA, D'Orb. See TEXTU-

LARIA.

VERRUCA'RIA, Pers.— A genus of Py-
renodei (Lichenaceous Lichens), containing
numerous species having a crustaceous or
cartilagineo-membranous thallus growing
upon and adherent to the bark of trees or
stones ; named from the wart-like processes
corresponding to the perithecia, which open
by a pore at the surface. The perithecia
have a black rind, enclosing either the
whole or the upper half of the nucleus,
The spermogonia much resemble the peri-

VERTEBBALINA,

[ 806 ]

VESSELS.

thecia, only they are much smaller; they
occur either scattered among the perithecia,
or collected towards the margins of the
thallus. Species very numerous.

BIBL. Hook. Br. Fl ii. pt. 1. 152 ; Leigh-
ton,Lich. Fl 444 ; Schserer, Enum. crit. 213 ;
Tulasne, Ann. Sc. Nat. 3. xvii. 215, pi. 3.

VERTEBRALI'NA, D'Orb.— A genus
of Porcellaneous Foraminifera, near Miliola.

Char. Shell free, regular, greatly com-
pressed, mostly inequilateral, more convex
on one side than on the other, suborbicular
or elongate ; spire embracing in the young-
state only, afterwards straight; chambers in
the spire, two or three; orifice a large
patulous aperture along the septal plane.
See ABTICULINA and RENULITBS,

One recent British species :

V. striata (PI. 23. fig. 10).

BIBL. Williamson, Rec. Far. 89; Car-
penter, Introd. For. 72.

VERTICIL'LIUM, Nees.— A genus of
Mucedines (Hyphpmycetous Fungi), distin-
guished from Botrytis (under
which it is included, with
Acrostalagmus, by Fries)
chiefly by the verticillate
arrangement of the sporifer-
ous branches. A number of
species are described; but,
from the observations of Hoff-
mann and Bail on the germi-
nation of Tricothecium, this
genus represents only one
form of the plants belonging
to other genera, — V. ruberri-
mum, Bonorden (Botrytis ver-
ticilloides, Corda, which Hoff-
mann regards as identical with
Acrostalagmus parasitans and cylindrosporoin.
cinnabarinus), having been Magnified 200
raised from the spores of Tri- diameterB-
chothecium roseum, and its " spores " being
barren (see TBICHOTHECIUM). Berkeley
and Broome describe and figure several new
species.

BIBL. Ann. N. H. 2. vii. 101, pi. 7.
figs. 15-18; Fries, Sum. Veg. (Botrytis),
491.

See also TBICHOTHECIUM.

VESICULA'RIA, Thomps.— A genus of
Infundibulate Ctenostomatous Polyzoa, of
the family Vesiculariidae.

V. spinosa, the only species, general on
marine shells, &c.

BIBL. Thompson, Zool. Elustr. 98 ; John-
ston, Br. Zooph. 370; Hincks, Polyz. 512.

Verticillium

VESICULARHM;.— A family of In-
fundibulate Ctenostomatous Polyzoa.

Char. Polypidom plant-like, horny, tubu-
lar ; cells free, deciduous, the ends flexible
and invertile. Genera :

Serialaria (Amathid). Shoots slender,
filiform, erect, branched ; cells tubular, ad-
herent, uniserial and unilateral, rows inter-
rupted by blank intervals ; tentacles eight.

Vesicularia. Shoots branched, jointed ;
cells oval, distinct, uniserial and unilateral ;
eight tentacles, and a gizzard.

Valkeria. Variously branched ; cells oval,
irregularly clustered ; eight tentacles, no
gizzard.

Mimosetta. Variously branched; cells
ovate, in two rows, opposite, jointed at the
base ; eight tentacles and a gizzard.

Avenella. Filiform, creeping, nearly
simple ; cells large, solitary, scattered, in one
row, slightly contracted at the top, curved;
twenty to twenty-four tentacles, and a small
gizzard.

Nolella. Cells erect, subcylindrical,
crowded on tubes which form an undefined
incrusting mat ; tentacles eighteen.

Boiverbankia (PI. 18. fig. 19). Matted
and creeping, or erect and irregularly
branched ; cells tubular, densely clustered ;
tentacles eight to ten, and a strong gizzard.

Farrella. As Bowerbankia, but tentacles
twelve to thirty, and no gizzard.

Anguinella. Branched palmately, one
tube springing from another, largely com-
posed of mud ; animals with twelve tenta-
cles and no gizzard.

BIBL. Johnston, Br. Zooph. 367 ; Gosse,
Mar. Zool. ii. 19 ; Hincks, Polyz. 512.

VES'PA,Linn. — Vespa wdyaris, the wasp,
and V. crabro, the hornet, are readily acces-
sible insects for the examination of the sting
(STING).

VESSELS OF ANIMALS. See ABTEBIES,
LYMPHATIC SYSTEM, and VEINS.

VESSELS OP PLANTS. — This name was
applied by the earlier observers to various
elongated tubular structures of vegetable
tissues, from an idea that they corresponded
with the vessels of animals ; and the name
is still retained. The spiral, annular, &c.
vessels are described under SPIBAL STBUC-
TUBES. The term vessel is now generally
contrasted with DUCT, to indicate a single
long tubular cell, or row of confluent elon-
gated cells, with spiral secondary deposits
upon their walls, in contradistinction to a
canal formed of a row of cells, with pitted

VIBRIO.

[ 807 ]

VILLI.

secondary deposits, applied end to end and
confluent. The LATICIFEROUS tubes are
sometimes called laticiferous or milk vessels.

VIB'RIO, Mull.— A genus of Schizomy-
cetee,

Char. Filiform, more or less distinctly
jointed from imperfect division ; flexible,
movement undulatory, like that of a ser-
pent.

These filamentous bodies are extremely
minute ; their simple structure is best seen
when they are dried.

V. rugtda (PI. 7. fig. 1&). Filaments
hyaline, - distinctly jointed, very tortuous
when in motion. Warming describes a
cilium. In decomposing infusions j breadth
1-12000".

V. bacillus (PI. 7. fig. 21). Filaments
elongate, hyaline, joints sometimes distinct
only after drying, flexuous in their slow
motion; length 1-288" ; breadth 1-1700".

Fig. 801.

V. serpens. Smaller than the last, with
three or four undulations. In infusions &c.

BIBL. Ehr. Inf. 77 ; Duj. Inf. 216 ; Ra-
benht. iii. 71.

Vibrio tritici= ANGUILLULA tritici.

VICTOREL'LA, Kent.— A genus of
Ctenostomatous Polyzoa. Cells formed in
open enlargements of the creeping stem ;
tentacles few ; no gizzard.

V. pavida, very minute ; on Cordylophora
lacustris, in brackish water.

BIBL. Kent, Qu. Mic. Jn. 1870, 31;
Hincks, Polyz. 559.

VILLI. — These are minute folds or pro-
longations of the mucous membrane of the
small intestines. They are most numerous
in the jejunum and ileum — in the former,
conical and flattened, sometimes plate-like,
cylindrical, club-shaped or filiform, while
in the latter they are broader and flat-
tened.

Fig. 802.

Fig. 801. Intestinal villus of a kitten, free from epithelium, and after treatment with acetic acid : a, boundary of
Sited ?350 diameters "'' *' muscular fibres; d, roundish nuclei in the middle of the rillus. l&g-

Fig. 802. A, magnified 75 diameters. Two villi with their epithelium, from a rabbit: a, epithelium; 6, paren-
chyma B, magnified 300 diameters. A row of detached epithelial cells: a, membrane separated by water ?*,
s™m?e i?h 1? f T Detached ePlth<^ cells : a with, 6 without the separated membrane ; c, surface view o

The villi form solid processes of the mu-
cous membrane, consisting of connective
tissue without elastic elements, but abound-

ing in roundish nuclei ; containing also
blood-vessels, lymphatics, and unstriated
muscular fibres.

VINCA.

[ 808 ]

VINE-FUNGUS.

The villi are exceedingly vascular, and
form beautiful microscopic objects when
injected, exhibiting a network of capillaries
with rounded or elongate meshes.

Fig. 803.

Fig. 803. Two villi from a calf, without epithelium,
and containing each a lacteal vessel ; after treatment
with dilute solution of soda. Magnified 350 diameters.

Each villus contains a lacteal, the origin
of which commences either in a single caecal
dilatation, or in a network of branches.

The muscular fibres form a thin layer,
not very distinct in man, surrounding the
lacteals, and capable of greatly contracting
or shortening the villi.

The epithelial cells are intimately con-
nected with each other, but easily detached
from the villi, often in groups or rows;
the free surface is longitudinally striated.
When acted upon by water, the cell-mem-
brane at the surface is separated, leaving a
clear space between the granular cell-con-
tents and the former.

BIBL. Kolliker, Mikrosk. Anat. ii.

VINCA, L.— The generic name of the
garden plants called Periwinkles ; interest-
ing to microscopists on account of their

striated , liber-fibres (PI. 48. fig. 30).
SPIRAL STRUCTURES.

Fig. 804.

See

Fig. 804. Two contracted villi, from a cat. Magnified
60 diameters.

VINE-FUNGUS. — The vine-mildew,
Oidium Tuckeri, Berk., which has in recent
years caused such extensive destruction, has
formed a subject of investigation for most
of the principal mycologists ; and notwith-
standing that its natural history is not yet
wholly cleared up, many interesting points
have been discovered. As it ordinarily
appears, it forms a white and very delicate
cottony layer upon the leaves, young shoots,
and fruit of the vine, soon causing a pro-
duction of brown spots upon the green
structures, and subsequently a hardening
and a destruction of the vitality of the sur-
face. Under the microscope, the white
substance is seen to be composed of delicate
ramified filaments, creeping horizontally
over the surface, and, when the plant is
much developed, forming a dense interlace-
ment. The horizontal filaments exhibit
few septa, these occurring at the points of
branching, and they do not penetrate into
the interior of the epidermal layer; here
and there, however, they are found fixed to
the epidermis by a more or less developed
organ of attachment, consisting of a disk or
lobed expansion, comparable roughly to the
so-called root of some of the Fucoid Algae,
which adheres firmly to the cuticle, and
when removed, leaves a brownish scar be-
hind. The destructive effect of the Fungus
seems to arise from its arresting the de-
velopment of the epidermis, by binding its
structures together, and excluding the sur-

VINE-FUNGUS.

[ 809 ]

VINE-FUNGUS.

face from the influence of the air, since
when young berries are invaded, the inter-
nal development proceeds, and the sphace-
lated epidermis preventing the natural ex-
pansion, the grapes burst and rot. In this
case, species of Botrytis, &c. appear upon
the decomposing pulp, as on all similar sub-
stances ; and these must be distinguished
from the proper mildew. When full-grown
leaves are affected to a moderate extent,
the vitality is often only partially affected,
causing a laxity of the tissue, and more or
less fading of the green colour, without
inevitable decay.

When the mildew is observed with a low
magnifier, its surface exhibits a mealy ap-
pearance, arising from minute bead-like or
pearly shining bodies of oval form ; and the
application of sufficient power shows that
the horizontal filaments bear numerous
erect branches or pedicels, consisting of
short-jointed filaments (PI. 26. fig. 8), the
terminal cells of which (or the last two) are
elliptical and expanded. These terminal cells
are soon matured, and then fall off; vast
numbers of them are produced, and are
found lying upon the surface among the
creeping filaments, where they quickly ger-
minate (PI. 26. fig. 9) and produce new
ramifications of mycelium. The fungus, as
thus described, constitutes the Oidium pro-
per ; and the deciduous terminal cells form
the so-called spores. But the history of
the development of the mildew does not
cease here.

In the first place, the detached l spores '
do not always produce a filament as repre-
sented in fig. 9; some of them present,
while still attached, a kind of segmentation
of the protoplasmic contents (fig. 10) ; and
detached examples are found filled with
minute f sporules ' of elongated-elliptical
form. These minute ' sporules ' are either
discharged by a dehiscence of the ' spore '
(fig. 11), and then germinate, or sometimes
they germinate in situ and send out slender
filaments through the walls of the spore.
We have found also that the large filaments
produced by the simple large { spore ' (fig. 9)
do not always at once form a regular myce-
lium, but sometimes give rise to slender
pedicels, terminating in a point bearing
minute solitary corpuscles of about the size
and form of the ' sporules' above described,
and resembling the spermatia of many of
the higher Fungi.

In addition to this, we have sometimes
observed those ' spores ' which produce the

' sporules ' in their interior, with their outer
membrane finely punctate ; and in very rare
cases this form of fruit was not composed
of a single terminal cell, but presented indi-
cations of cross septa, as if two or more
cells of the summit of the pedicel were con-
fluent into one sac ; here the punctuation
of the surface was very strongly marked.

Thus far we depend upon our own obser-
vations ; but Mohl, Tulasne, and others de-
scribe a still more highly developed fruit
than that last noticed : they have found the
terminal bodv> producing l sporules/ with a
distinct cellular coat (PI. 26. fig. 12), from
which the sporules are discharged by a ter-
minal dehiscence. Mohl found this body,
very rarely, of spherical form. We have
never seen this cellular coat j in the cases
we have met with, the coat was certainly
only punctate or tubercular ; probably the
structure was not mature, nevertheless the
' sporules ' were distinctly evident.

These phenomena, exhibited by the Vine-
fungus, clearly agree with those exhibited
by the Oidia always accompanying certain
ERYSTPH<E, as described under that article ;
and therefore most of the authors who have
written on this subject conclude that the
Vine-fungus is really an Erysiphe, of which
the perfect, ascophorous fruit has not yet
been discovered. A comparison of figure
12, PI. 26, from the Vine-, copied from
Mohl, with those of the Ho^-Erysiphe, fig.
14, will show the agreement of structure
between the two plants.

It remains only to add a few remarks as
to the interpretation or nomenclature of the
different organs. Mohl, Tulasne, &c. have
denominated the simple ' spores ' above de-
scribed (figs. 8, 9) conidia ; but as we have
stated, the cells are convertible into what
may be called sporanges, producing 'spo-
rules' (or true spores) without alteration of
structure. When their walls become cel-
lular (fig. 12), the sporangia! character is
more decided ; but as the Erysiphce produce
a more perfect sporange, in which asci are
developed, the name of pycnidia is applied
to them. This fruit it was which gave rise
to the establishment of a supposed distinct
genus, by Cesati, under the name of Ampe-
lomyces ; while Ehrenberg, also regarding
it as a distinct plant, made it the type of a
genus called Cicinobolus, on account of the
peculiar tendril-like extrusion of the l spo-
rules ' (fig. 12 a). Mohl distinguishes it as
the Cicinobolw-faiiit, which he, like Tulasne,
finds constantly associated with other (un-

VINEGAR.

[ 810 ]

VINEGAR-PLANT.

doubted) Erysipha (fig. 14), in very slightly
different and equally irregular forms.

There can be no doubt whatever, that it
is the cause and not a consequence of the
t murrain ; ' still there are various curious
circumstances connected with it not at all
understood. It is probable that peculiar
atmospheric conditions induce predisposing
states of the plants ; but the phenomena
are enigmatical : we have had it completely
covering a vine in a small greenhouse, de-
stroying all the fruit one year ; and although
no precautions were taken (as it was desired
to study the disease), no sign of mildew
appeared there the next year j while on an
out-door trellis, a few yards off, the disease
reappeared in a slight form in the second
season. The application of sulphur appears
to arrest the growth.

BIBL. Berkeley, Gardener's Chron. 1847,
no. 48 ; Jn. Hort. Soc. vi. 284, ix. 61 ; Mon-
tagne, Bull. Soc. Centr. Agric. 2. v. ; Jn.
Hort. Soc. ix. 112 ; Amici, Atti deW Accad.
de* Georqofili, xxx., Jn. Hort. Soc. viii. 231 :
Savi, ibid. 241 ; Tulasne, Bot. Zeit. xi. 257 j
Compt. Rendus, xxxvii. ; Thuemen, Pttze d.
Weimtocke, 1878.

VINEGAR, EELS IN. See ANGUILLULA.

VINEGAR-PLANT.—Under this name
is known a remarkable vegetable production
formed in fluids rich in sugar, when under-
going fermentation at ordinary temperatures
and conversion into vinegar. As ordinarily
met with, it forms a tough gelatinous mass
floating on the surface of the liquid, its
shape (superficially) defined by that of the
vessel in which it is contained, extending
itself so as to occupy the whole surface even
in very large pans, — its depth or thickness
depending on its a^e and the amount of nu-
triment contained in the liquid. The gela-
tinous substance decreases in density from
above downwards, the lower part being very
lax and flocculent, the inferior surface being
in a state of continuous development. The
general mass, however, displays remarkable
tenacity, which, together with its lubricity,
renders it difficult to tear ; but if the lower
surface is examined, it is found possible to
strip off layer after layer, each a few lines
thick, to an extent depending on conditions
of growth, the lower, less dense portion
being thus distinctly stratified.

When portions are placed beneath the
microscope, very varied forms of structure
are discovered in the interior. The general
mass of jelly appears structureless, as if
formed by some exudation, or solution of

the organized portion ; but the mode of ori-
gin of this jelly js not yet ascertained.
Imbedded in the jelly are cellular structures,
polymorphous indeed, but exhibiting trans-
itions which render it impossible to regard
them as of distinct origin. In the middle
portion often occur innumerable isolated
masses of short rows of cells, resembling
the cells of YEAST when coherent, except
that they are generally elliptical ; some of
them have short cylindrical joints : others
short cylindrical portions arising from long
tubular filaments, and terminating in ellip-
tical cells, so as to resemble exactly OIDIUM.
The diameter of all these structures is most
variable, from 1-4000 to 1-8000". In the
upper part, the elongated branched filaments
more abound, the length of the internodes
and the diameter of the tubes still varying
extremely. At the lower, laxer surface, the
cellular structures are accompanied by less
of the tough gelatinous matrix. The lami-
nation of the lower growing surface is very
curious, but may perhaps be accounted for
by supposing that the inferior growing sur-
face of the mass, which is certainly the
mycelium of a fungus, periodically produces
a crop of conidia, which become detached
and fall into the body of the liquid on which
the mass floats ; there quickly germinating,
they form a new entangled mass of filaments
and cha^lets of cells, which then acquires
its gelatinous consistence, and, buoyed up
by the liquid, applies itself against the lower
surface of the parent mass, with which it
adheres, more or less, on account of the gela-
tinous condition. In the upper part of old
and thick masses, the layers become insepa-
rable— probably in some measure from the
pressure of the floating force from below,
together with the condensation arising from
the evaporation of the liquid of the jelly at
the upper surface.

When a vinegar-plant is left upon the
solution after the saccharine matter is ex-
hausted, we find it always display, after a
certain time, patches of the ordinary fructi-
fication of PENICILLIUM«7/«MCWm (fig. 805),

as stated by Turpin and others, forming
green, blue, and yellow "mould" upon the
surface, and imbedded in the upper strata,
in which also heaps of the spores occur;
the vinegar sometimes ultimately suffers
more or less decomposition, so that the
common "mother" of vinegar, which by
its growth destroys the acidity, appears to
be another condition of this same organ-
ism. In some cases where we kept an

VINEGAR-PLANT,

[ 811 ]

exhausted liquid in Fig. 805.

the dark for some
months, the acidity
of the vinegar dis-
appeared, the gela-
tinous layer became
greatly condensed,
and assumed a bright
crimson tint, and re-
mained as a dull-red
membranous film,
somewhat like a
smear of blood when
dried upon paper.

From the above
observations it would
appear that the vine- Peniciiiium.

o-ar-plant consists ofHead of a fertile filament

themyceliumof Peni- %£*&£%$! ZLZStoZ.

cillium glaucum , vege-
tating actively and increasing also by crops
of conidia or gemmae. This opinion is en-
tertained by Turpin, Berkeley, and other
observers; and the various genera and species
founded on the different forms of structure
occurring in it cannot be entertained:
among these are Uloina, Kiitz., and species
of Hygrocrocis, Leptomitus, &c. But the
moniHform growth is at the same time
scarcely distinguishable from the Yeast-
plant by any satisfactory characters ; and
repeated observations strongly impress us
with the idea, that these objects are all
referable to one species, — the vinegar-plant
being the form of vegetative growth taking
place at low or ordinary temperatures in
highly saccharine liquids, while the true
yeast-plant 'or Torula is formed in the more
rapid fermentation taking place at more
elevated temperatures. Another circum-
stance, mentioned under PENICILLIUM, is
that we have found stale beer-grounds, kept
at a rather low temperature, always ulti-
mately acquire a gelatinous crust, on which
Penicilliitm-frmt becomes developed.

In connexion witli this subject may be
mentioned the objects called Cryptoccoccus
glutinis, Fres., and the " blood on bread,"
which appear nearly related to the red-co-
loured condition of the vinegar-plant above
mentioned. These are possibly merely forms
of the same plant ; indeed we have observed,
on some flour-paste partially covered with
Peniciiiium glaucum, small circular patches
of a crimson tint, which under the micro-
scope were found to consist wholly of mi-
nute elliptical bodies, generally exhibiting
two internal granules or "nuclei," and

exactly resembling the articulations of some
of the moniliform structures of the vinegar-
plant, which readily separate into their
component cells. All these phenomena
require further investigation, to which long-
continued and constant observation must be
applied in order to ascertain with certainty
the relation the different objects bear to
each other. It is a kind of research occu-
pying much time, and demanding great
care and patience, but calculated to repay
the trouble far better than the amassing of
isolated characters of forms seen at different
periods and under special conditions. Fur-
ther particulars concerning various points
treated in this article will be found under
the heads FERMENTATION, OIDIUM, PENI-
CILLIUM, TOUULA, and YEAST.

BIBL. Turpin, Mem. de I Institut, xvii.
135; Berkeley, Jn. Hort. Soc. iii.'Ol ; Lindley's
Med, Sot. 17; Fresenius, Beitr. z. My col.
Heft ii. 77 ; Slack, Tr. Mic. Soc. 1865, 10.

VIRGULA'RIA.— A genus of Pennatu-
lidee (Alcyonaria). V. mirabilis is found in
British seas, and has a long rod-like support
to the short polype-bearing fringes.

VIRGULI'NA, D'Orb.— A subgenus of
Bulimina, having outdrawn, very delicate,
and smooth biserial shells, with extremely
fine pores. The regular Virgulince are ty-
pified by V. squamosa, those of less regular
growth by V. Schreibersii. The only variety
taking on a sandy condition, becoming de-
licately rugose or subarenaceous, is V.Hemp-
richii, common in the Indian seas and in
some Tertiary and Cretaceous strata, having
muddy dull shells of very variable growth,
and presenting passages of form between V.
Schreibersii and Bulimina proper. See Bo-
LIVINA and BULIMINA. Common, recent
and fossil.

The extreme subcylindrical modification
of Virgulina is Pleurostomella, Reuss ; the
bi-uni-serial modification is Bifarina, P.& J.

BIBL. Ekrenbergj-Afifcro^.; Parker& Jones,
Phil. Tr. civ. 375 j Ann. N. H. 4. ix. 284,
299.

VIS'CUM, Linn.— A genus of Lorantha-
ceae (Dicotyledons).

V. album is the mistletoe, alluded to under
EMBRYO-SAC, LIBER, and OVULE.

VITREOUS HUMOUR or body. See
EYE.

VITT^E of the valves of the Diatomacese.
—These are internal projections or inflections
of the valves, forming imperfect septa ; they
appear as dark lines, visible under ordinary
illumination.

VITT^E.

[ 812 ]

VOLVOCINE.E.

VITT^E OF FRUITS. See SECRETING
ORGANS of Plants.

VITTA'RIA, Sm.— A genus of Grammi-
tidese (Polypodiaceous Ferns). Several
species ; tropical. (Hooker, Syn. 395.)

VOLUTELLA,Fr.— A genus of Stilbacei
(Hyphomycetous Fungi), comprising seve-
ral species of parasites which have been
variously distributed. The plants consist
of minute fleshy papillae (stromatd) of cel-
lular structure, the surface of which is
clothed with elliptic, oblong, or fusiform
stylospores, from between which project long
jointed hairs (fig. 806) traversing the stroma.

Fig. 806.

Volutella buxi.
Magnified 20 diameters.

It may be desirable to give the synonymy
of these plants according to Berkeley and
Broome.

V. ciliata, Fr. (Psilonia rosea, Br. Fl.).
Whitish or rosy ; on potatoes.

V. buxi) Berk. & Br. (Fusisporium buxi,
Br. FL). White; on dry box-leaves (fig.
806).

V. setosa, Berk. & Br. (Psilonia setosa,
Br. Fl. , JEgerita set., Grev.) . White, on wood
and herbaceous stems.

V. hyacinthorum, Berk. &Br. (Psil. hyac.,
Br. Fl.). White; stipitate ; on hyacinths
grown in water.

V. melaloma, B. & Br. Orange, with
black hairs; on sedges.

BIBL. Berk. Br. Fl ii. pt. 2. 352-3 ; Ann.
N. H. 2. v. 466, pi. 11. fig. 3; Greville,
Crypt. Fl. pis. 102 & 268. fig. 2 ; Corda, Ic.
Fung. ii. pi. 13. fig. 107 ; Fries, Syst. Myc.
iii. 447.

VOLVOCIN'E^E.— A family of Confer-
void Algaa; they were formerly included
among the Infusorial animalcules, among
which they form one of Ehrenberg's families.
The most striking general character of these
objects is their composition of individual
elements, which exhibit in their mature and
most perfect stage of existence, the charac-
ters of the transitory ZOOSPORES of the other
Confervoids. The Volvocinese may be cha-

racterized as plants composed of a number of
permanently-active zoospore-like bodies
associated together into families of definite
form, in which the members, connected or
held together in various ways by cell-mem-
branes, retain their distinct individuality for
all physiological purposes of nutrition,
growth, reproduction, &c., but represent only
one being in relation to the surrounding
objects. Protococcus, however, consists of
only a single cell. The best-known and
most beautiful example of this family is the
genus Volvox (PI. 7. fig. 24), consisting
when mature of a spherical membranous
sac, at the periphery of which, within the
membrane, are arranged a large number of
zoospore-like bodies (^omY&a),each provided
with a pair of cilia, which pass out through
the enveloping membrane, collectively form-
ing a coating ah1 over the external surface,
and by their vibration causing a rotary mo-
tion of the entire globe.

The modes of reproduction of the Volvo -
cineae, both vegetative and by spores, are
described under PANDORINA, VOL vox, and
GONIUM; hence it is unnecessary to dwell
on them here.

Char. Permanently active zoospore-like
bodies, ciliated (except Gyges), surrounded
by a gelatinous coat (like COCCOCHLORIS) ;
solitary or combined in definite groups, with
or without a common enveloping membrane.
Individuals pyriform, or with the body pro-
longed posteriorly.

Solitary.
Without cilia

r Protococcus.

\ (Chlamidomonas.)

With a pair of cilia

Grouped.
Forming a square layer, goni- -. GoniwTOt

dia with two cilia /

Forming a spherical body.
Cilia solitary.

With a " tail " Uroglena

Without a " tail."

With an eye-spot, go- )
nidia dividing into > Sphcerosira*
clusters )

Cilia two.

Without an eye-spot. . . Synura*.
With an eye-spot.
Common envelope spherical.

Gonidia numerous, all \ •^•f.jnnr.

over the periphery.../ V(
Gonidia eight, in a cii

Common envelope ellipsoidal, gonidia sixteen

or thirty-two Pandorina.

* Probably stages of development of VOLVOX or PAN-

DOBINA.

VOLVOX.

[ 813 ]

VOLVOX.

See SPONDYLOMORUM and SYCAMINA.
BIBL. See the genera.
VOLVOX, L. — A genus of Volvocinese
(Confervoid Algae), of which only one spe-
cies, V. globator (PI. 7. fig. 24), seems satis-
factorily established. This organism, occur-
ring not uncommonly and often in great
abundance in clear pools on open commons,
&c., appears to the naked eye as a minute
pale-green globule gently moving about in
the water ; its dimensions variable, but gene-
rally about 1-50" when full-grown. When
placed under a low magnifying power, it is
found to be a spherical membranous sac or
coenobium, studded all over with green points,
the entire body rolling over in the water
with a motion which is readily discerned to
be caused by innumerable cilia arranged
upon the surface of the globe. In the inte-
rior of the sac are generally seen dense
globes, in summer mostly of a green colour
(PL 7. fig. 24) : sometimes the cavity is
wholly filled up by a number of membranous
sacs exactly resembling the parent but de-
formed by mutual pressure (PI. 7. fig. 25) ;
and inside these are seen smaller green
bodies as in the former case. The cceno-
biurn is also flexible, yielding to pressure
and recovering its form, and in full-grown
specimens is generally ruptured at one point,
where the internal bodies escape, so that
the number varies; usually, however, the
original number is eight.

The application of higher powers is requi-
site to discover the intimate structure of
Volvox, which, by the researches of Wil-
liamson and Busk, most of whose observa-
tions we have verified, has been pretty
clearly made out. The outer envelope con-
sists of a layer of cell-membrane, in all
probability composed of a modification of
cellulose, although we have never succeeded
in producing more than a faint purple tinge
with sulphuric acid and iodine. By the
application of a sufficient magnifying power,
the green corpuscles at the periphery are
found to consist of zoospore-like bodies (go-
nidia, PI. 7. fig. 28), which are seated inside
the membranous envelope, each sending out
its pair of vibratile cilia (figs. 24-30) through
separate orifices in the external coat. The
same investigation will reveal that the
green gonidia have radiating processes ex-
tending from their sides, and running from
the different centres to meet each other in
the light interspace, forming thus a kind of
delicate network beneath the membrane.
The gonidia are pyriform, have a transpa-

rent anterior end bearing a pair of cilia,
and contain a reddish-brown eye-spot and
a contractile vacuole, thus exactly resembling
those of Gonium, and indeed the zoospores
of Confervoids generally. The radiating
processes resemble those found in particular
stages of PROTOCOCCUS pluvialis, running
through the gelatinous coat, and probably
may be compared to the radiating fila-
ments proceeding from the nucleus of SPI-
ROGYRA (PI. 9. fig. 26). There is somewhat
more difficulty in determining the nature of
the structure in which the gonidia are en-
closed. There is a layer of soft consistence
of some thickness within the external mem-
brane; the green gonidia are wholly im-
bedded in this ; and their radiating processes
and cilia traverse the substance of it. We
are inclined to believe that this presents a
firm membranous layer again at the internal
surface, looking toward the general cavity
of the sphere. The nature of the soft layer
has been the subject of discussion ; we be-
lieve Busk's view to be correct, that it is
not formed by the collocation of distinct
membranous cells, like those of ordinary
parenchymatous structures, but by the close
juxtaposition of gelatinous envelopes of the
individual green bodies, resembling those
of Coccochloris, Glceocapsa, &c. We could
never detect a true line of demarcation
halfway between neighbouring gonidia :
an appearance is indeed sometimes pre-
sented in preparations kept in chloride of
calcium, which might lead to an error on
this point ; for the outer membrane is then
sometimes swollen into papillae opposite
each corpuscle (PI. 7. fig. 30), the furrows
between which in certain foci give the ap-
pearance of a septum running round each
corpuscle (PL 7. fig. 29). Similar prepara-
tions also often show the gonidium con-
tracted and leaving an empty ring round
it, separating it from the gelatinous coat,
w7hicn runs undistinguishably into those of
the neighbouring gonidia. But the strongest
fact we have observed is that, by the appli-
cation of solution of potash, the substance
surrounding the gonidia is so entirely dis-
solved that the oily substance extracted
from the green bodies will run freely about
beneath the external membrane (apparently
confined internally by another film), in
sheets extending over considerable segments
of the sphere, yet leaving the gonidia and
their radiating processes intact, or at least
only shrunk and discoloured. If a true cell-
membrane existed around each gonidium,

VOLVOX.

[ 814 ]

VORTICELLA.

forming septa dividing them, the above
phenomenon couldnot display itself, since the
potash would not so dissolve the structures.

The modes of reproduction of Volvox
have recently been entirely elucidated. In
certain conditions, some of the gonidia ap-
pear larger than the rest, and as if under-
going division (PL 7. fig. 27) ; it is possible
that some of the gonidia, or of such grouped
gonidia, escape into the cavity, and there
become developed into the large green bo-
dies (PI. 7. fig. 24), which are rudimentary
globes j but Williamson believes these are
detached in an earlier stage : perhaps both
modes of development take place. Forms
with the grouped gonidia (PI. 7. fig. 29)
would appear to represent Ehrenberg's
Sphcerosira. Ehrenberg's genus Uroglena,
again, would seem to be a Volvox either im-
perfectly developed or decaying.

The deep-green bodies (PI. 7. fig. 24),
seen in the cavity of the spheres, are young
Volvoces, and in an early stage they appear
as spherical cells filled with granular green
substance ; the green substance divides by
segmentation (PI. 7. figs. 31, 32) until it
forms a group of gonidia, on each of which
a pair of cilia appears , the enclosing mem-
brane expands, and they follow it and re-
move apart, until they form a perfect Vol-
mr-sphere, studded with the gonidia. As
above mentioned, a second generation is
sometimes met with in the parent sphere
(PI. 7. fig. 25). We are uncertain whether
to regard the objects represented in PI. 7.
fig. 14, as the young of Volvox ; they would
seemingly equally represent the genus Pan-
donna, Syncrypta, or Eudorina, Ehr.

Volvox, examined in autumn and early
winter, often exhibits either the green bodies
with a thick coat (PI. 7. fig. 33), or the inner
globes are of an orange colour (PI. 7. figs. 26
& 34), which appear to be successive stages
of development of a resting-spore. When
mature, this possesses at least two coats,
one immediately surrounding the granular
contents, another at some distance outside
the former, transparent, colourless, and as
it were glassy and brittle, breaking with
sharp-angled cracks when pressed (PL 7.
figs. 34 & 35). We cannot detect any in-
termediate substance or layer, which would
be required to complete the analogy with the
resting-spore of SPIROGYRA as described
by Pringsheim (PL 9. fig. 21) j perhaps it
does not exist in either case. Sometimes
the outer coat of the enclosed yellow globes
is tuberculated or covered with conical ele-

vations (PL 7. fig. 36). The form with the
| smooth yellow resting-spores (PL 7. figs. 26
| & 34) represents Ehrenberg's Volvox aureus,
i and the form with the spines (PL 7. fig. 36)
I his V. stellatus. The development of the
! resting-spores of Volvox has been fully de-
scribed by Cohn, and presents an essential
resemblance to the process in PANDORINA
I and STEPHANOSPH-ERA. Some of the
i gonidia become enclosed in special cyst-like
| coats j and their contents are then converted
j into spermatozoids, which break out and
move actively in the interior of the spherical
common envelope. These bodies fertilize
other gonidia, which take on the function
of spore-cells ; and after their impregnation
the latter acquire the firm coats and yellow
contents characteristic of the resting-spores.
They are set free at first into the common
cavity of the spherical envelope.

A doubt remains as to the nature of the
object described as Synura uvella ; it may
belong here, or, not improbably, to the
genus Uvella (PL 32. fig. 18), which itself
may be no more than a complex form of
PBOTOCOCCUS or Chlamidomonas (PL 7.
fig. 2 ; PL 23. fig. 30), which doubtless in-
cludes also Chloroyonium (PL 30. fig. 31),
Cryptoglena (fig. 35), and Gyges (PL 50.
fig. 14).

When a pool contains Volvox, the indi-
viduals are generally abundant, and may be
readily seen by the naked eye, as pale-green
globules, in a phial of water held up to
the light ; but they are kept with difficulty,
being devoured by ROTATORIA, &c. The
cilia are best seen by drying and wetting
them again, or by applying iodine. The
gonidia are a good deal altered by chloride
of calcium.

BIBL. Ehr. Inf. ; Pritchard, Inf. ;
Williamson, Tr. Phil. Soc. Manchester, vol.
ix. ; Tr. MM. Soc. 2.i. 45 ; Busk, ibid. 31 ;
Cohn, Ann. So. Nat. 4. v. 323 ; Ann. N. H.
2. xix. 187 ; Rabenh. Alg. iii. 26 ; Cooke,
Alga, 1882.

VORTICEL'LA, Linn.— A genus of
Peritrichous Infusoria, of the family Vor-
ticellina.

Char. Body campanulate, with an ante-
rior ring of cilia, stalked j stalk simple, spi-
rally contractile.

These interesting Infusoria are very coni-
nionlv met with in decomposing vegetable
infusions, as of hay, portions of dead
flowers, &c. Their curious metamorphoses
and modes of reproduction, are noticed under
INFUSORIA.

VORTICELLINA.

[ 815 ]

WATER.

F. nebulifera (PL 32. fig. 21). Body
conico-carnpanulate, colouiiess ; anterior
margin dilated; body without rings when
contracted. Length of body without the
stalk 1-570 to 1-288".

V. microstoma (PI. 32. fig. 26, body
with gemmae). Body ovate, narrowed at
the ends, greenish white; anterior margin
not dilated, nor body ringed when con-
tracted. Length of body 1-2000 to 1-250".

r. convallaria. Body ovato-conical,
whitish hyaline, annulate; expanded ante-

rior margin slightly prominent. Length of
body 1-430 to 1-240".

Many other species.

Dujardin unites the genera CarchexiKin
and Zoothamnium to his genus V&rticetta.

BIBL. Ehr. Inf. 269; Duj. Inf. 546;
Lachmann, Ann. N. H. 1857, xix. ; Clap,
et Lach. Inf. ; Greef, Ann. N. H. 1872, 105,
196, 384, 462 ; Allman, Mn. Mic. Jn. xiv.
178 ; Kent, Inf. 667.

VORTICELLI'NA.— A family of Infu-
soria.

Table of Genera.

- -I
Q

Without a pos-
terior crown I
of cilia during 1
the greater
part of life. \

Naked.

Sheathed.

(A. peduncle.

INo pedun-
cle.

Peduncle
contrac-
tile«

G-EXUS.

VorticeUa.

Not branched

/'Each branch haTing a

Branched. J A ^Tta^hrf <Maium'

( muscle Zoothamnium.

Peduncle not contractile Epistylie.

i, j' i_ I No funnel ... ... Scyphidia.

by a disk. J *r

,No disk Gerda.

( No true sheath, the peduncle lost in a gelatinous mass Ophrydium.

Animal fixed to
the base of the

*» nr m* > Sheath fixed by its base Cothurnia.

A sheath. 4 JJeaS^ f Sheath fixed by its side Vaglnicola.

Animal suspended freely in the sheath Lagenophrys.

With a posterior ciliary crown during the whole of life; body free Trichodina.

BIBL. Clap. & Lach. Inf. 93; AUrnan,
Qu. Mic. Jn. 1872, 393.

VORTICLA'VA, Alder.— A genus of
Hydroid Zoophytes.

"Char. Polypes on simple stems, developed
at intervals on a creeping filiform stolon ;
tentacles in two dissimilar whorls, the oral
short and capitate, the outer longer and
filiform ; reproduction unknown.

Two species, on stones and corallines.

BIBL. Jiincks, Hydr. Zooph. 131; Wright,
Qu. Mic. Jn. iii. n. s. 50.
\nJLVULI'NA,D'Orb.— SeeTEXTULAEiA.

W.

WART. — The common hard wart con-
sists of a circular group of elongated papillae
with their free extremities slightly enlarged
and bulbous, their vessels dilated and ex-
tending close up to the epithelial covering.
This presents its normal threefold division,
inasmuch as a thick layer of transition-cells
fills up all the interstices between the en-
larged papillae, while the horny lamina in-
vests the group of papillae with a common
covering. (Rindfleisch, Path. Hist.}

WASP. See VESPA.

WATER.— Under this head we might
form a kind of index referring to a large
proportion of the articles of which this

volume is composed, since water, existing
under different circumstances, forms one
of the most fertile sources of microscopic
objects ; but as our space and plan do not
admit of such an enumeration, we must be
content to dwell shortly upon two of the
most important questions in which the mi-
croscope is applied to the examination of
the contents of water.

Ordinary examination of water. — Here it
appears merely necessary to point out that
the mode of examining the contents of sam-
ples of water, for the purpose of ascertaining
the extent to which organic beings are con-
tained in them, should be very different
from that pursued by the microscopist who
is engaged in collecting specimens. We
make this remark in consequence of the
gross misrepresentations which have been
made respecting the " animalcules " in
water, carried to their most absurd extreme
in the so-called " drop " of water shown by
oxyhydrogen microscopes, where we often
see the field covered with larvae of dragon-
flies, of beetles, of gnats, &c., Entomos-
traca, and worms of different kinds, not
only preceptible without a microscope, but,
in the case of the larvae, perhaps really more
than an inch long. Less violent exagge-
rations occur when water which appears
cloudy is selected, allowed to stand for some

WATER.

WEISSIA.

time, and the sediment examined. Very
false results must also be obtained when
water is exposed to the air for any length
of time before examination, since Infusoria
and microscopic Algae always appear in a
short time, even in distilled water, when
exposed to the atmosphere; and an un-
covered water-butt or cistern will be found
a very fertile source of microscopic objects.
We regard the presence of most of those
organisms which do not sufficiently affect
the water to render its impurity discernible
by the naked eye, as a matter of little con-
sequence. Large numbers of Entomostraca,
certain Rotatoria and Infusoria, and Oscil-
latoriaceous Algae, generally very perceptibly
clouding or colouring the water, of course
indicate the presence of much decomposing
organic matter in the water, which, how-
ever, reveals itself very^ clearly in a short
time when the water is kept, by a fetid
odour. The presence of green Confervoid
Algae is by no means a sure sign of impurity
properly so called, in water ; for some will
only grow in very clear and pure water,
while many of them may be regarded as
agents of purification. The presence of
Zygnernaceae, Diatomacese, and especially
the Schizonaycetes, is, however, particularly
objectionable, as they become very fetid in
decomposition, which generally takes place
very soon «when they are disturbed and
injured. When large numbers of minute
Algae appear in water, discolouring it over
extensive surfaces, the microscope will en-
able us to detect the nature of the object pro-
ducing the appearance, but will scarcely be
requisite to prove the impurity of the water.

The microscope is also of great importance
in detecting the presence of undigested and
bile- stained particles of food, showing the
admixture of sewage with water.

Coloration of water. — Under this head
we shall refer to those plants and animals
which most commonly produce such ap-
pearances, premising that the commonest
cases of coloration depend upon suspended
mineral substances (mud), of different colours
according to the soils washed by the water.

1. Producing a general green colour, or a
thick film on the surface. — PROTOCOCCUS
( Chlamidomonas, Ehr., Diselmis, Duj.), very
common in the spring ; and various Nosto-
chaceous Algae, as TRICHORMUS, OONIO-
PHYTUM, &c. (see NOSTOCHACE^E ; many
with a bluish tinge); CLATHBOCYSTIS (form-
ing a granular verdigris-green layer), Mi-
CBOHALOA, and various other PALMELLA- |

CEJE and CONFERVACE^ • EUGLENA viridis,
&c. The DESMIDIACE^E form greenish
patches at the bottom of water or on plants,
as do certain OSCILLATORIACE^E.

2. Producing a red colour in fresh water.
— ASTASIA hcematodes, Ehr. ; species of
DAPHNIA. TUBIFEX produces a red colour
on the mud in shallow water. Red forms of
species of PROTOCOCCUS (see also RED
SNOW). — In salt water, DISELMIS Dunalii,
Duj.; TRICHODESMIUM.

3. A brown cloudy appearance often ap-
pears in masses near the source of small
springs of water flowing out of blue clay,
or in pools on peat-bogs. This mostly con-
sists of peroxide of iron ; but sometimes a
similar brown appearance is produced in
pools by collections of amorphous granular
decaying organic matter, in which occur
great abundance of certain OSCILLATORS,
DIATOMACE^,!NFUSORIA, and ROTATORIA.
The obscure mycelioid structure called by
Kiitzing LEPTOTHRIX ochracea produces a
yellowish-brown tint ; DIDYMOHELIX also
gives abrown colour to water. Diatomaceae
often form a yellowish-brown coat on mud
at the bottom of water. Many Rotatoria
and the larger Infusoria (PARAMECIA, &c.),
when abundant give water a slightly milky
appearance.

The ordinary method of separating the
organic bodies from water, is to place it in
a conical glass, and allow them to subside.
A little spirit or osmic acid should be pre-
viously added to prevent growth or repro-
duction. The bodies are then removed
with a pipette, or separated by filtration
through Swedish paper.

The above list is undoubtedly very im-
perfect, but may afford some useful hints.
Microscopists who meet with such colora-
tions will naturally examine them carefully ;
they will find further information under the
heads of the articles cited.

BIBL. Macdonald, Soc. Sci. Congress,
1877 ; Scott, Jn. Mic. Soc. 1877, Mn. M.
Jn. xviii. 237 ; Church, Water, 1877 ; Fox,
Food fyc. 1881; Cohn, Seitr. z. Biol i.
108; Blyth, Food $c. 1881; Frankland,
Water- Analysis.

WATER-BEARS. See TARDIGRADA.

WEBBI'NA, D'Orb. (Restricted.)— A
subgenusof Trochammina ; adherent, single-
celled, moniliform, or alternating. Recent
and fossil.

BIBL. Parker and Jones, Phil. Tr. civ.
435; P..J., & Brady, Monog. Crag For. 25.

WEISSIA, Hedwig.-A genus of Pot-

WESTWOODIA.

[ 817 ]

WHALEBONE.

tiaceous Mosses, variouslydefined by authors,
related to Gymnostomum. W. controversa
( W. viridula, Mull.) is common on banks.
Wilson includes Blindia here, and separates
W. fug ax and denticulata as Rhabdoweissia.
(Wilson, Bryol Br. 46.)

WESTWOODIA, Dana, = Arpacticus
pt. W.nobilis=Arp.nob.', marine. (Brady,
Copep. ii. 140.)

WHALEBONE.— In whales the teeth
are rudimentary ; and arising from a depres-
sion in the upper jaw on each side are a
number of parallel horny plates, many feet
in length, which project downwards: these
platf.-, which are technically known as fins
or blades,constitute whalebone ; and through
them the water containing the animals upon
which the whale lives is strained, and the
food thus obtained. These plates are situ-
ated upon a vascular membrane, folds of
which enter a cavity at their base, which is
the portion connected with the jaw.

Whalebone may be pretty easily divided
into longitudinal laminso and fibres ; but
these are only secondary forms resulting
from the aggregation of a number of cells
of which whalebone wholly consists.

On examining a transverse section of a
blade or plate of whalebone with the naked
eye, or a lens, two structures are readily
distinguishable — an inner porous-looking
medullary portion, surrounded by an outer
compact or cortical substance. A longitu-
dinal section through the plate exhibits a
number of dark lines or stripes, from about
1-100 to 1-150" in diameter, parallel to each
other and to the axis of the plate, and cor-
responding to the pores seen in the trans-
verse section. These stripes, which have
been called whalebone-canals, but which we
shall denominate medullary lines, are seen
to be surrounded by a paler substance.

With a higher power (£ inch), the trans-
verse section exhibits in the centre a num-
ber of rounded apertures or circles corre-
sponding to the pores (PI. 22. fig. 31), sur-
rounded by very fine, concentric, interrupted
dark lines, whilst towards the circumfer-
ence these lines run parallel to the surface
of the plate. In the longitudinal section,
viewed with this power, the medullary lines
are seen to consist of a number of cells
(PL 22. fig. 30), mostly arranged in single
longitudinal series, and, in dried whalebone,
having a very dark appearance by trans-
mitted light, from the presence within
them of a large quantity of pigment and
air. These are the medullary cells. The

substance between the lines of medullary
cells exhibits very fine longitudinal striae,
and, in parts, the ends of divided laminae.

On macerating whalebone for twenty-
four hours in solution of caustic potash, it
becomes soft ; and on afterwards digesting
it in water, the cortical portion resolves
itself into numerous large transparent cells
from 1-230 to 1-310" in length, and from
1-500 to 1-330" in breadth (PI. 22. fig. 33).
These contain a variable number of gra-
nules of pigment, of a deep brown colour,
also some small globules of fat, which are
especially numerous in those portions near-
est the base of the plate. These cells in the
natural whalebone are laterally compressed
or flattened ; and the transverse axes of
those surrounding the medullary lines are
arranged tangentially to the latter, whilst
in the cortical portions these axes are par-
allel to the surface of the plate. The con-
centric lines seen in a transverse section
arise principally from the pigment-granules
within those cells which surround the me-
dullary cells becoming arranged in a linear
series by the flattening of the cells enclo-
sing them. This may be shown by treat-
ing a transverse section of whalebone' with
caustic potash, and then adding water and
watching its resolution into cells. As these
expand, the interrupted lines are seen also
to expand as it were, and to become re-
solved into a number of distinct pigment-
granules existing within each cell. The
lines seen in a longitudinal section arise
from the unequal refraction of light by the
laminae of compressed cells surrounding the
medullary lines.

The medullary cells contain a large quan-
tity of pigment, as do also those compressed
cells which immediately surround them j in
the former these granules are frequently
aggregated. In the common dry whale-
bone of commerce the medullary cells also
contain air, which has been mistaken for
fat, and hence the cells denominated fat-
cells. The air is readily displaced by liquids.
Between the compressed cells, minute ca-
vities containing air, sometimes assuming a
linear form, at others representing mere
dots, are seen both in the transverse and
longitudinal sections ; these are distin-
guished by the displacement of their con-
tents. Hence ordinary whalebone closely
resembles hair or horn in its structure ; and.
the fibres which are seen projecting from
the margin of the blades as found in com-
merce have a remarkable similarity to hair

WHEAT.

[ 818 ]

WOOD.

(PL 22. fig. 32). Chemically, it consists of
a proteine compound, and is therefore co-
loured by Millon's and Pettenkofer's test-
liquids.

Whalebone polarizes light like horn.
BIBL. Hunter,PM. Trans. 1787; Bonders,
Mulder's Phys. Chemie^ Lehmann, Phys.
CJiem.

WHEAT.— The STARCH of the grain of
wheat (Triticum wily are and other species
and varieties) presents itself in the form of
delicate little flattish lenticular bodies, very
characteristic (PL 46. fig. 8). Wheat is
subject to various BLIGHTS, which are re-
ferred to under that head, depending on
the growth of parasitic Fungi, especially
TILLETIA, attacking the ear, PUCCINIA
attacking the straw, &c. In other cases the
ear is found infested with a minute worm
(ANGUILLULA tritici) remarkable for its
tenacity of life.

WINGS OF INSECTS. — The arrangement
of the veins or nerves of the anterior wings
of the Hymenoptera is sometimes used to
form the basis of systematic arrangement ;
and the several veins and interspaces have
received distinct names, which may be illus-
trated by reference to PI. 34. fig. 11, repre-
senting the anterior wing of the humble-
bee (JBombus terrestns) : «, costal nerve ;
b, hind margin ; c, inner margin of wing,
with the fold (K) for the attachment of the
hooks ; d, postcostal nerve j e, externo-me-
dian ;/, anal ; the nerve between 3 and 10, the
trans verso-median ; A, anterior or outer mar-
gin ; I, the subdiscoidal ; s, stigma ; 1, costal
cell ; 2, externo-median cell ; 3, interno-
median ; 4, anal ; 5, radial or marginal ; 6,
first cubital cell ; m, m, m, second, third,
and fourth cubital cells; 10, first discoidal
cell; 11, second ditto; 12, third ditto; 13,
first, and 14, second apical cell.
See INSECTS, wings.

BIBL. That of INSECTS; Jurine, Nou-
velle Methode ; Shuckard, Tr. Entom. Soc.
i. ; Staveley, Miss, Neuration, Linn. Trans.
xxiii. 125; Semper, Siebold £ KolUker's
Zsitschr. viii. 326.

WINTE'RE^E.— A section of the Dico-
tyledonous family Magnoliaceae (DniMYs,
Tasmannid), remarkable for the character
of the elementary structure of the wood,
approaching closely to that of the Conifene,
It consists, as in that family, wholly of
pitted prosenchymatous cells without ducts,
the cells having two or three rows of bor-
dered pits as in ARAUCARIA. A distinc-
ion exists, however, in the character of the

medullary rays, which are very numerous in
Wintereee, occurring both large and small,
six or seven in the breadth of 1-12" in a
vertical section at right angles to the rays —
some of them being thin, composed of one
or two parallel layers of cells, extending to
a vertical extent of about ten cells, others
much larger, ten or twelve cells thick (or
broad), and of a vertical extent of eighty or
a hundred cells ; the latter are very evident
on the surface of the wood when the bark
is removed. The medullary rays here tra-
verse all the annual layers of wood, which
is not the case in the Ooniferse.

BIBL. Goeppert, Linncea, xvi. 135 (1842) ;
Ann. Sc. Nat. 2. xviii. 317.

WOOD. — The mode of origin of wood is
explained in the articles CAMBIUM, ME-
DULLA, MEDULLARY RAYS, and VASCULAR
BUNDLES, while the characters of the ele-
mentary organs of which wood is composed
are described under the heads of CELL ;
FIBROUS, PITTED, and SPIRAL STRUC-
TURES ; and SECONDARY DEPOSITS. Pe-
culiar composition of the wood in certain
classes, families, or genera of plants is also
noticed under their special heads, which
will be referred to presently. In this article
the principal modifications of the wood, as
a whole, occurring in these and certain
other cases, are to some extent classified,
in order to indicate their relations, and to
furnish a guide to microscopists seeking to
observe the most remarkable varieties of
structure, occurring in this substance.

The elements entering into the composi-
tion of wood are : — 1, FIBRO-VASCULAR
BUNDLES, which in their most complete
form contain SPIRAL and other VESSELS,
PITTED DUCTS, PROSENCHYMATOUS cellular
tissue with thickened walls (ivoody fibre) ;
and in the Monocotyledons, vasa propria,
as they are called by Mohl, viz. elongated
tubular cells of membranous structure oc-
curring in the centre of the bundles. 2,
MEDULLARY RAYS in the Dicotyledons, or
a generally diffused medullary parenchyma
in the Monocotyledons. 3, Woody PAREN-
CHYMA, which is found under different con-
ditions and in different quantities in differ-
ent cases.

The GYMNO SPERMS may be considered
in the above enumeration as agreeing with
the Dicotyledons. The less-generally dif-
fused structures connected with Secretion
are here left out of view.

In classifying the kinds of wood, we may
commence with the less perfect forms.

WOOD.

[ 819 ]

WOOD.

Monocotyledons. — In our native plants of
this class the stem is mostly herbaceous,
and the woody structure then occurs sim-
ply in the form of u fibres " (Jibro-vascular
bundles, fig. 456, p. 495), the structure of
which has been described elsewhere (fig.791,
p. 800). The same kinds of elements are
arranged in nearly the same way in most of
the arborescent plants of this class, such as
Palms — for example, in the Cocoa-nut Palm,
in the common Cane (Calamus), or the
various striped solid canes (all Palms) used
for walking-sticks, £c. The solid woody
texture depends in these upon the inter-
space between the fibro- vascular bundles
being filled up with woody parenchyma ; i. e.
the general medullary substance, which in
such stems as that of the White Lily is soft
and spongy, in the Palms &c. becomes soli-
dified by the great deposition of secondary
layers upon the walls of the cells ; thus
the bundles, at first "fibres," are bound
together into a solid wood. The thick
woody walls of the hollow Bamboo cane
are constructed on the same plan, being
highly developed and lignifiea forms of
the structure which is exhibited in a soft
and herbaceous condition in our common
Grasses.

Certain Monocotyledons present a struc-
ture which differs from the above in the
appearance presented by transverse sec-
tions. In the Sniilaceae, and some of the
Dioscoreaceae, the fibro -vascular bundles are
arranged in more definite order in one or
two circles ; but there is no distinction of
pith, medullary rays, and bark here; the
bundles are bound together by woody par-
enchyma, and there is no cambium-region
beneath the rind. The anomalous growth
exhibited by the stems of other Monoco-
tyledons, such as Draceena, Yucca, &c.,
cannot be regarded as depending on the
formation of wood in the proper sense j in
them, layers of fibrous structure are formed
between the central region of the stem
(containing the original vascular bundles)
and the rind, which take their origin from
the ends of the vascular bundles at the
periphery of the stem beneath the rind, and
extend down in a kind of false cambium
layer beneath the rind.

Interesting objects illustrating the above
structures are furnished by longitudinal and
transverse sections of the trunks of large
Palms and of the large woody leaf-stalks of
these, of canes of different kinds, of Bamboo
canes, the rhizome of Sarsaparilla plants

(Smilax), Ruscus, the harder parts of the
stem often found attached to imported
Pine-apples, &c. Sections of silicified fos-
sil Palm-stems, prepared by the lapidary,
can also be obtained from the dealers in
objects.

Dicotyledons. — In this class we meet with
a remarkable diversity in the character of
the wood, which moreover here exhibits,
from the indefinite power of growth of the
FLBRO-VASCULAR BUNDLES, a much more
extensive and perfect development than in
the Monocotyledons. In the articles ME-
DULLA (fig. 455, p. 495), MEDULLARY RAYS
(fig. 457, p. 496), and VASCULAR BUNDLES
(fig. 792, p. 801) are described the condi-
tions of ordinary Dicotyledonous stems in
the first year of their growth ; it is stated
in the account of the vascular bundles, that
a new layer of wood is developed in the
cambium layer in each succeeding season
(fig. 457, p. 496). The nature of the ele-
mentary structures in such cases is illus-
trated by the accompanying figures from the
Maple (Acer campestre, figs. 807 & 808),

Fig. 807.

Transverse and vertical section of a segment of a

fibres; PC, cellular envelope of the bark; 8, corky layer
of ditto. Magnified 60 diameters.

3G2

WOOD.

Fig. 808.

[ 820 ]

WOOD.

I me c f

v f c t in.

Transverse section of Maple-wood three yearo old.
The figures 1, 2, 3 indicate the annual rings of wood ; the
rest is bark, m, medulla ; t, spiral vessels ; v, ducts ;
/, woody fibre ; c, cambium ; me.medullary parenchyma ;
I, liber. Magnified 40 diameters.

of which the former represents sections of a
shoot at the begining of its second year,
• when the cambium layer (c) is swelling,
the latter a shoot of three years' growth,
the portions belonging to each year being
indicated by the figures. The only differ-
ence between the structures developed in
each succeeding season is the absence of a
layer of spiral vessels (medullary sheath, in
the first year) at the point where each year's
growth commences. Here, as is seen, the
body of the wood is composed chiefly of
prosenchymatous cells (wood-cells or woody
fibre,/), with a few pitted ducts (v) near
the commencement of each annual layer ;
the medullary rays are narrow in this wood.
In the Hornbeam (Carpinus Betulus) the
wood is of very similar composition ; the
wood-cells, however, are more thickened,
and the ducts exhibit a spiral marking ; the
annual layers are not very clearly defined in
sections under the microscope. This is the
case, again, with the excessively hard wood
of the Box (Bujcus sempervirens), which is of
analogous composition. The Birch (Betula
alba) has the same structure. Other com-
mon timber-trees exhibit an additional
structure in their wood, namely masses
woody parenchyma interspersed in various
ways among the ordinary prosenchymatous
structure of the wood. A very small quan-
tity of this occurs in scattered groups in the
common Oak (Querctts pedunculata) ; here
also the ducts are very large, appearing as
open holes to the naked eye in cross sec-
tions ; the larger medullary rays are like-
wise very evident. In the Beech (Fagu
sylvaticd) there is a small quantity of woody

larenchyma, but greatly thickened prosen-
hyma prevails ; the ducts are rather small ;
>ut the broader medullary rays are very
evident, appearing to the naked eye as
}rown streaks in longitudinal sections. The
Chestnut (Castanea vesca) differs from this
chiefly in wanting the broader medullary
•ays. In the Elm (Ulmus campestris) the
prosenchyma is interposed between bands
}f woody parenchyma and wide ducts,
which renders the distinction of the annual
ayers obscure. The Walnut-tree has no
woody parenchyma j the Apple- and Pear-
trees have alternate bands of prosenchyma
and woody parenchyma; these exist, but
are narrower, in the Plum and Cherry. In
the wood of most of the Leguminosee
(Robinia, Ulex, Genista, Gleditschia, &c.)the
woody parenchyma appears in bands of con-
siderable size ; but the walls of its cells are
less thickened than those of the prosenchy-
matous cells. Woody parenchyma occurs
extensively in Mahogany and Kose-wood,4
producing a peculiar variation of colour in
the wood ; the large holes are the orifices
of the very wide ducts.

The wood of the Poplars (Populus), and
Willows (Salix), has the prosenchymatous
cells little thickened. The Hazel (Corylus
Avellana), and the Alder (Alnus glutinosa),
present a peculiarity : the wood appears to
the naked eye to have broad medullary rays ;
but under the microscope these rays are
found to be portions of the wood devoid of
ducts, intervening between segments with
closely-pitted ducts placed at particular
points in the annual rings. The Lime
(Tilid) and the Horse-chestnut (^Esculus)
have wood of soft texture, the prosenchy-
matous cells being only slightly thickened,
while the ducts are large and numerous
(these exhibit a spiral band, very evident in
the Lime). The wood of the Plane (Pla-
tanus occidentalis) has strongly marked
medullary rays ; the prosenchymatous cells
are greatly thickened; and mingled with
them are very numerous ducts, and a small
quantity of woody parenchyma. The stem
of the Vine (Vitis viniferd) has likewise
long and broad medullary rays ; the wood
is composed of prosenchymatous cells, with
a spiral-fibrous deposit on their walls, while
the cells of the woody parenchyma are
devoid of this ; the ducts are very long, and
exhibit every gradation of form, from spiral,
reticulated, and scalariform to pitted ducts.
The various species of Clematis have strongly
marked medullary rays, and wood chiefly

WOOD.

[ 821 ]

WOOD.

composed of pitted ducts, as is the case also
in the common Rose.

In many of the above trees, the wood
acquires a special peculiarity when it attains
a certain age; the prosenchymatous cells
generally become more solid, year by year,
through" the filling-lip of their cavities by
the increasing thickness of the secondary
deposits on their walls: in the lighter-
coloured and softer woods, such as the
Lime, there is no distinct line of demarcation
between the older and younger part of the
trunk — the alburnum or sap-wood and the
duramen or heart-wood ; but in nanny cases,
as in the Ebony (Dwspyros), Lignum vitae
(Guaiacum), to a less extent in the Elm,
Oak, &c., the duramen assumes a remark-
able solidity and a deeper colour, so that
after a certain time the colours of the dura-
men and alburnum are very different. This
appears to arise from a chemical alteration
of the substance of the secondary deposits
of the prosenchymatous cells.

A great degree of regularity and agree-
ment of structure exists between the woods
of the Dicotyledons above mentioned. It
remains to direct attention to various kinds
which depart more or less from the type
thus selected.

In the various parasitical Dicotyledons,
such o.&Lathrcea, Melampyrum, Cuscuta, &c.,
there is no layer of spiral vessels corre-
sponding with the medullary sheath ; and
in the Mistletoe ( Viscum} only annular ducts
occur in this situation; the wood in the
latter is largely composed of woody paren-
chyma, the cells of which are punctated, or
possess spiral-fibrous layers (figs. 665, 666,
page 712). The stem of Myzodendron also
exhibits some remarkable anomalies.

In the Bombacese (Bombax, Carolinea,
£c.) the mass of structure corresponding
to the wood is chiefly composed of mem-
branous parenchymatous cells, with scat-
tered isolated prosenchymatous cells, and
large pitted ducts. The wood ofAvicennia is
principally composed of large pitted ducts,
with narrow interspaces filled up with small
pitted parenchymatous cells.

The wood of the Cactaceae (Mammillaria,
Melocactus] is composed of dotted ducts,
together with a kind of cell, apparently re-
ferable to parenchyma, the walls of which
have a remarkably "broad spiral-fibrous band
(PL 48. fig. 7). The wood of the Casuarinee
exhibits a curious structure : it is composed
of long prosenchymatous cells, the walls of
which, together with those of the numerous

large ducts, have bordered pits (PI. 48.
fig. 2) ; while concentric lines of cellular
tissue appear at intervals in the cross sec-
tion, consisting of plates of parenchyma
extending from one medullary ray to the
next, and connecting them. The stems of
some of the Menispermaceae have likewise
concentric processes of parenchymatous tis-
sue. In the WINTEKE^E, a section of the
Magnoliaceae, the wood is wholly composed
(with the exception of the medullary sheath)
of pitted prosenchymatous cells resembling
those of Araucaria (PI. 48. fig. 5), without
any ducts.

In certain families of Dicotyledons a
remarkable appearance arises from the ar-
rangement of the bundles in several circles,
almost as in the Monocotyledons ; but this
results in a very different kind of structure,
on account of the unlimited growth of the
cambium in Dicotyledons. Examples of
this kind of wood occur in the Chenopo-
diaceae, Nyctaginaceae, Piperacese, &c. In
Pisonia, which has been supposed to grow
I in the same way, the result is a solid mass
| of wood, composed of prosenchymatous cells
', and ducts, with isolated perpendicular cords
of parenchyma (exactly the reverse of what
occnrs in the Monocotyledonous stems).
The woods of Phytocrene and Nepenthes
may be further cited as offering remarkable
peculiarities.

It would exceed the space which we can
allow to this article to enter into a descrip-
tion of the anomalous Dicotyledonous stems
of the tropical lianes or climbing trees, of
the JSignoniacecs, Menispermacece, Malpighi-
| acea, &c. ; the irregularities of the wood
I of which depend upon deviations from the
j normal type arising in the course of the
i growth of the stems, which, from the obser-
| vations of Treviranus, Criiger, and others,
appears to be mostly regular when quite
j young. Isolation of one or more fibro-vas-
! cular bundles from the central cylinder of
! wood, producing distinct centres of develop-
i ment, is the most common cause of irre^u-
larity.

The wood of Dicotyledons must be exa-
mined by transverse sections, and perpendi-
cular sections parallel with and at ri^ht
angles to the medullary rays. The same
applies to the wood of Gymnosperms. The
mode of cutting these sections is stated
elsewhere.

Sections of recent woods are best pre-
served wet in chloride of calcium. Fossil
wood, if silicified, is cut by the lapidary's

WOOD,

[ 822 ]

WOODWARDIA.

wheel; wood in the state of coal in like
manner (see PREPARATION, FOSSIL WOOD,
and COAL).

Gymnosperms. — In this division of the
Flowering Plants we also meet with two
types of structure :

Coniferce. — Here the character of the
wood agrees in general with that of the
typical Dicotyledons, with certain distinc-
tions ; namely, although the medullary
sheath of spiral vessels exists, no ducts or
vessels occur in the mass of wood external
to this, which is wholly composed of pros-
enchymatous cells, with "bordered pits, in
single (Plate 48. fig. 4) (usually), double, or
treble (Araucaria) rows (fig. 6) ; in Taxus
accompanied in part by a spiral-fibrous band
(fig. 4). The particulars of these forms are
given under CONIFERS. It may be men-
tioned that the " woody parenchyma " of
Dicotyledons seems to be represented here
by the cords of parenchymatous cells in
some cases traversing the prosenchyma, ulti-
mately filled with resinous deposits (" cords
of secretion-cells").

Cycadacece.— The earliest condition of
the stems here appears to resemble that in
Coniferse ; but no annular rings are formed.
Concentric layers are produced at intervals,
however, separated by parenchymatous
layers. The true mode of origin of these
does not appear to be clearly made out.
The wood is composed of pitted prosenchy-
matous cells (PI. 48. fig. 20), without ves-
sels or ducts, excepting in the medullary
sheath of spiral vessels.

Some elaborate and interesting researches
on the peculiar intimate structure of wood
and tissues have been published by Har-
ting, Sanio, Na'geli, and Hanstein ; but we
have no space to analyze these long papers
here.

For further details on the markings of
the ducts, &c., see PITTED and SPIRAL

STRUCTURES.

BIBL. Lindley, Intr. to Sot. ; DeCandolle,
Organographie, i. 161 ; Meyen, Pflanzen-
phys. i. 331; Goeppert, Struct. Conifer.
1841, Linntea, xvi., xvii., Ann. So. Nat. 2.
xviii. 1 & 317 ; Brongn. Veget. Fossiles, 1828,
et seq., Ann. So. N. 1. xvi. 589; Hooker,
Flor. Antarct., Ann. So. Nat. 3. v. 193;
Gaudichaud, Recherches Anat., and Ann.
Sc. Nat. 3. passim; Meneghini, Ricerche
sulla Slruttura Monoc. ; Schacht, Pftanzen-
zelle, 193, Das Baum, 94 ; Criiger, Sot. Zeit.
viii. 99, x. 465 ; Tr<§cul, Ann. Sc. Nat. 3.
xviii., xix.; xx., 4. i., ii., Hi. j Milde, Seitr. z.

Sot. 1850 ; Hanstein, Pringsheim's Janrb. i.
232; Sanio, Linncea, 1858; Hartig, Sot.
Zeitung, xvii. ; Henfrey-Masters, Sot. ;
Sachs, Sot. ; Kny, HolsJcorper, 1882.

WOOD'SIA, Brown.— A genus of Dick-
soniese (Polypodiaceous Ferns), represented
by two rare indigenous species, W. llvensis
and hyperborea. Sori globose ; indusium
inferior, cup-shaped or globose, sometimes
enclosing the sorus, opening at the top, the
mouth or margin irregular, iobed or fringed
with long hairs (fig. 809). Several tropical
species. (Hooker, Syn. 46.)
Fig. 809.

Woodsia hyperborea.

A sorus and indusium with a hair-like fringe.
Magnified 50 diameters.

WOODWAR'DIA, Smith.— A genus of
Blechnese (Polypodiaceous Ferns). Several
species; exotic.

Fig. 810.

Woodwardia.
A fertile pinnule. Magnified 5 diameters.

WOOL.

[ 823 ]

XYLARIA.

WOOL OF ANIMALS. See HAIR. The
fibres of wool are coloured by the test-
liquids of Millon and Schultze.

WRAXGE'LIA, Ag.— A genus of Cera-
miaceje (Florideous Algrc), differing- from
Grijjtthma chiefly in the scattered tetra-
spores. W. muJtifda, the only British spe-
cies, has rose-red feathery fronds, an inch
high, consisting of a main filament, about
as thick as a bristle, composed of a single
row of cells, bearing long, pinnately-ar-
rangfd, patent branches, mostly branching
in the same way again. At the articula-
tions occur two opposite (or more rarely a
whorl of) pinnato-multifid or subdichoto-
mous ramelli 1-12 to 1-6" long. The fruc-
tification consists of: — 1, favellee, borne on
stalks at the joints, and surrounded by a
whorl of ramelli; and 2, elliptical tetra-
spores, opposite, secund or tufted, on
the lower part of the ramelli. In some
foreign species antheridia have been ob-
served in similar situations to the tetra-
spores.

BIBL. Harvey, Mar. Alg. 169, pi. 24 D ;
Phyc. Brit. pi. 27 ; Derbes and Solier, Ann.
Sc. Nat. 3. xiv. 273, pi. 35 ; Thuret, ibid. 4.
iii. 38.

X.

XANTHID'IA.— The bodies found in
flint, and thus called, are probably sporangia
of Desrnidiaceffi (PI. 25. figs. 22-28). They
have been distributed in genera and species,
the description of the characters of which
would be useless.

It is a curious circumstance, that these
sporangia should be found in flint, which is
of marine origin, considering that the Des-
midiacese are none of them marine.

XANTHID'IUM, Ehr.— A genus of Des-
rnidiacese.

Char. Cells single, constricted in the
middle; segments compressed, entire, spi-
nous, with a circular, usually tuberculated
projection near the centre. Spines more
than two to each segment.

X. armatum (PI. 14. fig. 23; fig. 24,
empty cell, showing the projections). Seg-
ments broadest at the base; spines short,
stout, tri- or multi-fid; length 1-180".

X. fasciddatum (PI. 14. fig. 25). Seg-
ments with from four to six pairs of subulate
marginal spines; central projections minute,
conical, and not beaded ; common ; length
1-400".

Sixteen species,

BIBL. Ralfs, Br. Desmid. Ill; Rabenht.
Alg. iii. 221 ; Archer, l\it 'chard's Infus

XANTHIOPYX'IS, Ehr. -A genus of
fossil Diatomacege, consolidated with PYXI-
DICULA. It consisted of those species the
margins of the valves of which are furnished
with a dentate membrane, or the surface
covered with setae or hair-like processes.
Bermuda.

BIRL. Ehr. Ber. Berl Akad. 1844, 264;
Kiitz. Sp. Alg. 23 ; Pritchard, Infus. 826.

XENOD'OCHUS, Schlecht.— A genus of
Uredinei (Hypodermous Fungi), consisting
of black tufts, found on the leaves of Pote-
rium, containing microscopic, short, curved,
usually shortly stipitate filaments, attenu-
ated at each end, composed of a moniliform
row of (five to fifteen) globose cells filled
with black granules.

These bodies occur associated with Uredo
miniata, of which X. carbonarius appears to
be the perfect form. Xenodochus is only
distinguished from PHRAGMIDIUM by the
greater number of joints.

BIBL. Schlechtendahl, Linncea, i. 237,
pi. 3. fig. 3; Fries, Sum. Veg. 505; Ber-
keley, Ann. N. H. i. 263.

XENOSPH^E'RIA, Trevis.— A genus of
Micro-lichens, parasitic on the thallus of
Solorina saccata.

Char. Spores 6-8, oblong, 4-6-locular,
brown ; sometimes large, irregular, and
rnuriform.

BIBL. Korber, Syst. 326; Lindsay, Qu.
Mic. Jn. 1869, 344.

XESTOLEBE'RIS, Sars. — One of the
CyiheridcBy with subtriangular valves, higher
behind than in front, smooth, with distant
papilla; lower antennas with 4 joints;
upper 6-jointed, with simple setae, and
short. Two living British species, com-
mon.

BIBL. Brady, Tr. Linn. Soc. xxvi. 437.

XIPHIAS'TER, Murray.— A genus of
Ixodea (Acarina). Flat, with a long pro-
jecting rostrum and long applied palpi ;
abdomen beaded behind. X. rostratum,
Old Calabar. (Murray, EC. Entom. 201,

%.)

XIPHICHPLUS, Brady.— One of the
Cytheridce, near Paradoxostoma ; with sub-
equal, compressed valves, elongate, pointed,
thin, and smooth. Two living British spe-
cies, rare. (Brady, Nat. Hist. Tr. North.
$ Durh. iii. 369).

^ X YL A'RIA, Schrank.— A genus of Sphse-
riacei (Ascoinycetous Fungi), several of
which are common on rotten wood, stumps

XYLEM.

824 1

YEAST.

of trees, &c. They are branched, horny or
fleshy bodies, with often clavate lobes,
whitish and mealy when young, afterwards
brown or black, with black, horny, im-
mersed perithecia all over the branches, or
with the tips barren ; the perithecia have a
black centre composed of asci, each contain-
ing eight (usually uniseptate) spores.

BIBL. Berk. Br. Fl ii. pt. 2. 234; Fries,
Sum. Teget. 381.

XY'LEM. — Nageli's name for the woody
tissue forming part of the fibro-vascular
bundles of stems. It is composed of spiral
vessels, woody fibres, pitted ducts, and
wood-parenchyma.

X YLOG'RAPHA, Fr.— A genus of Gra-
phidei, Lichenaceous Lichens.

Char. Apothecia black, linear, plane, in-
ternally ashy ; spores 8, simple. 4 sp., rare.
(Leighton, Lich. Flora, 390.)

Y.

YEAST(-PLANT). — This well-known
substance, which possesses the remarkable
property of resolving sugar in solution into
alcohol and carbonic acid, consists of a mi-
nute fungus, or rather of a particular condi-
tion of development of a certain fungus.

When yeast from an actively fermenting
liquid is examined with the microscope, it is
seen to consist of myriads of minute cells or
vesicles, about 1-3000 to 1-2400" (PI. 26.
fig. 23) in diameter, containing a nucleus
and some granules. During the progress of
the fermentation, these cells increase in
number, by budding, until either the sugar
or the nitrogenous matter of the fermenting
liquid is exhausted, when the cells, especially
those nearest the surface, become elongated,
remaining connected end to end, until they
reach the surface, where they produce their
fructification.

The growth of the yeast-plant has been
carefully studied by several observers. We
may describe some observations of our own,
which confirm those of Mitscherlich and
others. Some fresh wort, in which fermen-
tation had commenced, was obtained from a
brewery, and a drop of the liquid, containing
yeast-globules, placed upon a slide and co-
vered with a piece of thin glass. After the
removal of the extraneous liquid, the upper
glass plate was cemented to the lower one ;
the slide was then placed under the micro-
scope, with the l-4th object-glass and the
micrometer eye-piece, in such a manner that
several well-formed globules were visible ;
and these were drawn on ruled paper.

At first the globules or cells enlarged until
they had attained a certain size ; then there
elapsed a short interval, during which no
change was observable. Next there took
place a projection of some point of the cell-
wall, which first appeared as a little point-
like bud, afterwards becoming larger and
larger, until at last a new cell, of the size of
the parent cell, was formed. Within three
hours a cell was so far developed that a
new one was formed from it, and thus an
independent individual perfectly developed.
The rapidity of growth probably varies with
the temperature and the nature of the
process : in twenty-four hours, when the
thermometer was at about 78° in the day,
sixteen cells were developed from one. After
a time the growth slackened ; finally no fur-
ther increase took place, undoubtedly be-
cause all was removed from the liquid which
could serve for their growth. Growing glo-
bules from this experiment are figured in
PI. 26. fig. 23.

Berkeley and Hoffman went a step further,
by contriving to get an atmosphere of air
round the drop of sugar and water, and
saw the cells of the yeast-fungus as soon as
it reached the air developed into a Peni-
cittium.

By the observations of numerous compe-
tent investigators, it seems certain that the
fermentation of Deer, of wine, and in fact
all vinous fermentation, is effected by the
growth of this plant ; and after the evidence
brought forward in the articles FERMENTA-
TION, TORULA, and VINEGAR-PLANT, there
is little doubt that the Vinegar-plant, the
Oidium lactis, and other supposed distinct
plants are but forms of the Yeast-plant.
PI. 26. fig. 24 exhibits the condition of the
Yeast-plant on the surface of exhausted
wort of malt, before the Vinegar-fungus
appears ; fig. 756, page 773, the Torttla~ftirm
at the margins of the surface of liquids.

We cannot clearly make out any difference
between the Hop yeast' and l bottom yeast'
(Oberhefe and Unterhefe of the Germans),
beyond the difference resulting from more
or less active development : when the
growth is rapid the cells are more spherical
and become quickly detached, and the evo-
lution of gas comes up more to the surface ;
when the yeast vegetates quietly at the
bottom of the liquid, its cells are more
elongated. We do not believe the yeast-
cells ever burst to discharge reproductive
granules. The globular form is known by
various names, as Mycoderma cerevisia,

YEW.

[ 825 ]

ZOOSPOKES.

Desm., which agrees with Cryptococcus glu-
tinis, Kiitz. ; the globular form in the Vine-
gar-plant is Kiitzing's Ulvina aceti; the
filamentous form with simple moniliform
fruit (fig. 756) is Tontla cerew'site, Turpin ;
without fruit, species of Hvyrocrocu or Lep-
fomifus, the final form being apparently
PenicilUum rjlaucum (PI. 26. fig. 15).

The Yeast-plant is truly most ubiquitous ;
but so are the conditions for its growth,
while its reproductive power is enormous,
and its small size renders it liable to be
scattered by imperceptible movements of
the air. Aspergillus glancus is almost as
constant in its favourite nidus, cheese;
Mucor mucedo on paste, &c. ; Botrytis vul-
iin.ri* on dead leaves and stems in damp
places, &c. : and all these are certainly not
pseudomorphic productions ; and if, as we
believe really to be the case, yeast is but
the conidial form of PeniciUium glaucum,
there has been no lack of the spores of the
latter in the air, in any situation where we
have ever exposed vegetable substances for
any length of time to a damp atmosphere.

Rees has lately observed in yeast, which
he calls Saccharomyces, that when sown on
plaster of Paris, or some convenient sub-
stance, certain cells at length swell and
contain sporidia. But after the fact that
sporidia are developed within the threads
of Chionyphe and in Hemileia, this does not
seem of much consequence.

The Yeast-fungus is often developed in
ripe grapes, causing vinous fermentation.
In an article published in Ann. d. Sc. Nat.
the globules are regarded by Karsten as
merely pathological; but this is contradicted
by the facts above mentioned.

BIBL. Turpin, Mem. de Vlnstitut, xvii.
93 ; Lowe, Tr. Edinb. Bot. Soc. 1857 ;
Bail, Flora, 1857, 417; Berkeley, Crypt.
Bot. 242, 299 ; Karsten, Ann. N. H. 4. xiii.
161 ; Rees, Alkoholgahrungspilze, 1870 ;
Sachs, Bot. 254 ; and the Bibl. of FERMEN-
TATION.

YEW. See TAXUS.

Z.

ZA'MIA, Lindl. See CYCADACEJE.

ZAN'CLEA, Gegenbaur. — A genus of
Corynidae, Hydroid Zoophytes.

Char. Stem simple or branched, rooted
by a creeping filiform stolon ; polypes more
or less clavate. Tentacles capitate, scat-
tered over the body ; gonophores borne on
the body of the polype and producing free
medusiform gemmae.

Z. implexa, marine, on shells, stones, &c.

BIBL. Gegenbaur, Versuch eines Syst. d.
Mcdnsen, Zeit. f. wiss. Zool. 1856, 229-
Hincks, Hyd. Zooph. 58.

ZAUS, Goodsir. — A genus of Copepodous
Entomostraca. Two species, marine. (Brady,
Copep. ii. 153.)

ZETES, Koch.— A genus of Arachnida,
of the order Acarina and family Oribatea.
It is consolidated with Galumna.

• ZINC .—The crystals of the lactate, as
deposited from an aqueous solution, are re-
presented in PI. 11. fig. 20 ; they belong to
the right-rhombic prismatic system.

The chloride of zinc is useful as a preser-
vative of animal tissues. (See PRESERVA-
TION.)

Chloriodide of zinc. See SCHULZE'S TEST.

BIBL. That of CHEMISTRY.

ZOEA. — The larval stage of some of the
higher Crustacea.

ZONARIA, Harvey (Aglaozonia, Zanard,
Kiitz.).— A genus of Dictyotaceae (Fucoid
Algae), of which the British species, Z. par-
vula, forms olive-green, membranous, fan-
shaped fronds, 1" or more in diameter,
growing over stones or corallines, to which
it attaches itself bv whitish fibres on the
lower surface. It is scarcely marked with
concentric lines like PADINA. The fructifi-
cation occurs in scattered sori on both sur-
faces, and is apparently analogous to that of
PADINA, but requires further examination,
since Thuret has shown that the true Dicty-
otacesB have peculiar reproductive organs,
spores, tetraspores, and antheridia, so that
they stand between the Fucaceae and the
Florideae.

BIBL. Harvey, Mar. Alg. 38, pi. 6 D:
Thuret, Ann. Sc. Nat. 4. iii. 25.

ZONOTRIC'HIA, Ag.=AiNACTis and
EUACTIS. (Rabenht. Alg. ii. 212.)

ZOOGLCEA, Cohn. See BACTERIUM.

ZO'OID. — The more or less completely
independent organisms, produced by gem-
mation or fission, whether these remain at-
tached, or are liberated and set free. (Ni-
cholson, Zool.)

ZO'OPHYTES, or Ccelenterata. See
ANIMAL KINGDOM, and POLYPI j also
Hamann, Organism. Hydroidpolypen, 1882.

ZO'OSPORES.— The name given to the
ciliated active gemmae orGoNiDiA produced
either singly or, more frequently, after
segmentation, in numbers, out of the con-
tents of ordinary or special cells of the Algae,
without any previous process of fertilization.
These bodies are generally discharged from

ZOOSPORES.

[ 826 ]

ZOOSPORES,

the parent cell in the state of PRIMORDIAL
UTRICLES, and acquire a cellulose coat
subsequently, when they cease to move,
and settle down to germinate and produce
a structure resembling the parent. In some
cases (in HYDRODICTYON normally, in many
other Confervoids abnormally) they become
encysted within the parent cell ; and it ap-
peal's most probable that the small cysts with
dense and often spinulose coats, such as
occur in Spirogyra (PI. 9. figs. 24, 25) and
other genera under certain circumstances,
are of similar origin. In the VOLVOCINE^,
zoospore-like bodies form the permanently
active individuals of the families.

True zoospores occur pretty generally
throughout the Confer void Algae, with the
exception of Oscillatoriaceae, Nostochaceae,
and perhaps Diatomacese, and are described
under the heads of the families or genera.
A brief review may be permitted here. The
largest form is that produced in the apices
of the filaments of VATJCHERIA (fig. 796) ;
it is ciliated all over, and very unlike that
of any other genus. In CEdogonium (PI. 9.
fig. 7 c, & fig. 811) the zoospores are formed
out of the whole contents of a cell, and have
a crown of cilia around the transparent
'beak.' In other Confervaceae, &sClado-

fhora (PL 9. figs. 13 6, c), Conferva (figs.
0 6, 11 c) ; in Chaetophoraceae, as in
Chaetophora (fig. 9), Draparnaldia (fig.
180, page 271), Stigeoclonium (PI. 9. fig.
5cc); in UlvacejB, Ulva (PI. 9. figs. 26,
3c, d), Enteromorpha (fig. 46); in Proto-
coccus (PI. 7. fig. 2 6), in ACHLYA, in Desmi-

Zoospores of CEdogonium. a have lost their cilia ;
and in 6 germination is more or less advanced. Mag-
nified 300 diameters.

diaceae (PI. 10. fig. 11), &c., as in all other
cases, they are formed either singly from
the entire contents, or in small or large
number by the segmentation of the entire
contents, and mostly break out in various
ways, as pyriform bodies with two or four
cilia on the transparent beak, moving ac-
tively for a time, and then germinating to

produce new plants. They appear usually
to be surrounded at the moment of discharge
by a delicate common sac, composed of
cellulose, which expands and quickly dis-
appears, apparently by solution, setting them
free ; in PEDIASTRUM, however, this enve-
lope appears to be permanent and to hold the
gonidia together in the characteristic group
or family (PI. 10. fig. 11). In HYDRODIC-
TYON, as described under that article, their
history is different, though the earlier con-
ditions are analogous. It has been found
that zoospores of two very different sizes
are produced in many Confervoids: these are
called macrogonidia and microgon dia by
Braun(see HYDRODICTYON) ; and a different
function is supposed to be exercised by the
latter by some authors, who believe they are
fertilizing bodies (like SPERMATOZOIDS).

Zoospores exist in a large proportion of the
Algae usually included under the FUCOIDE^,
but which Thuret separates under the name
of Phaeosporeae. The PhaeosporeaB have
sporangia containing motile zoospores, bi-
ciliated like the spermatozoids of the Mela
nosporeae (or Fucoideae). This separates
them from the latter. The Phaeosporous
families bear organs called SPORANGES
(usually described in Algological works as
spores), from which are discharged zoospores
agreeing in all essential respects with those
of the Confervoids, except that the two cilia
are often arranged fore and aft, instead of
being both in front. Examples of these are
described under ECTOCARPUS, MYRIONEMA,
CUTLERIA, LAMINARIA, &c. Zoospores
have been discovered in Fungi (Perono-
spora and Cystopus) by De Bary, and in
Lichens by Famitzin ; and if Saprolegnice
are really aquatic Fungi, their existence is
then notorious (PI. 27. fig. 27). See SAPRO-

LEGNIA.

It remains to direct attention to the di-
stinction between ZOOSPORES and SPER-
MATOZOIDS, which are sometimes confused
together. This confusion is rendered more
imminent by the manner in which the forms
pass one into another. The essential charac-
ter of a zoospore is, that when separated from
the parent, it usually becomes encysted and
at once developed into a new individual
resembling the parent. An exception to
this occurs in some of the zoospores of
CEDOGONIUM, which, as the androspores,
produce special structures in which are de-
veloped spermatozoids. And in many cases
the zoospores conjugate, before becoming
encysted (CONJUGATION).

ZOOTEIRA.

[ 827 ]

ZYGNEMA.

Spermatozoids are transitory structures;
when discharged from the parent cell, they
either make their way to a germ-cell of a
spore, fertilize it and disappear, or, if de-
barred from this, at once perish without
germination. As stated under SPERMATO-
ZOIDS, these bodies vary much in form. In
the higher Cryptogamia they are spiral fila-
ments (PI. 40. figs. 31-4). In the Fucaceae
they are minute globular bodies with two
cilia (fore and aft) closely resembling some
zoospores ; in the Florideae they are globules
without cilia : and those recently described
as existing in VAUCHERIA, among the Con-
fer voids, are also biciliated globules with
the cilia fore and aft, while those in SPH^E-
ROPLE^E resemble the microgomdia of this
family, having their pair of cilia on the beak ;
in (EDOGONIUM they resemble the zoospores,
but are smaller. The latter observation is
in favour of the microgonidia of Hydrodic-
ti/on, &c. being spermatozoids.

ZOOTEI'RA, Wright.— A genus of Ac-
tinophryina (Rhizopoda).

Char. Body furnished with numerous
contractile acuminate rays, elevated on a
contractile pedicel ; the rays become thick-
ened towards the point when not fully ex-
panded.

BIBL. Wright, Pritchartfs Infusoria,
563.

ZOOTHAM'NIUM, Ehr.— A genus of
Vorticellina (Peritrichous Infusoria).

Char. Body like Vorticetta, usually of
different shapes, attached to the ends of
a branched zoary ; internal muscle branched
and continuous. Many species, salt and
fresh water.

Z. arbuscula (PI. 32. fig. 22). Branches
of polypidom racemose-umbellate, bodies
white, stalks very thick. Freshwater;
length of polypidom 1-4" ; of bodies 1-430' '.

BIBL. Ehr. Infos. 288 ; Stein, Inf. ; Clap.
& Lach. Inf. 101 ; Kent, Inf. 693.'

ZOS'IME, Boeck.— A genus of Copepoda.
Z. typica, in dredgings. (Brady, Copepoda,
ii. 14.)

ZOS'TERA, L. — A genus of Monocotyle-
douous Flowering plants (Nat. Ord. Zostera-
ceae), growing in sea-water ; remarkable for
the POLLEN, of which the grains are repre-
sented by tubular filaments destitute 01 an
outer coat and exhibiting ROTATION when
fresh.

ZYGNE'MA, Agardh, in part (Tynda-
ridea, Bory, Hassall). — A genus of Zygne-
maceae (Confervoid Algae), consisting of
filamentous plants, with the green contents

| of the cells arranged in twin stellate or lobed

masses in each joint (fig. 137, page 204).

This stellate appearance arises from the

| presence of radiating threads, like those from

i the nucleus of SPIROGYRA ; hence it cannot

j be well observed in dried specimens. Cell-

| division with previous division of the

i stellate masses may be well studied in this

| genus. Kiitzing separates from this genus

all the forms in which the spore is formed

in the cross branch produced in conjugation,

associating them with Zygogonium. We

prefer to follow HassaU's distribution of the

forms, seeing that Zygogonmm ericetorum

is a plant of very different appearance. If

the said character is constant, this genus

might be divided into two.

Spores in one of the parent cells.

Z. crimata (fig. 137, p. 204). Filaments
1-600" in diameter ; joints equal or twice
as long ; spores globose (Hassall, /. c. infra,
pi. 38. fig. 1 ; Kiitz. /. c. infra, v. pi. 17.
fig. 4). Z. Dttlwynii and stellina of Kutzing
appear to be only smaller states of this, as
also Tynd. lutescens, Hassall, and T.anomala.
Ralfs.

Z. stagnate. Filaments 1-2640" in dia-
meter, joints three or four times as long ;
spores globose or oblong (Hassall, /. c.
pi. 38. figs. 9, 10). Tynd. ovalis, Hass., is
perhaps a larger form of this.

Z.insignis. ^ Filaments 1-1800 to 1-1560"
in diameter, joints twice as long; spores
globose (Hass. /. c. pi. 38. figs. 6, 7; Kiitz.
I.e. v. pi. 17. fig. 1).

Z.bicornis. Filaments 1-440 to 1-200"
in diameter, joints twice as long; spores
globose (Hass. I c. pi. 38. fig. 5 ; Kiitz. /. c.
v. pi. 16. fig. 3).

Spores in the cross toanches.

Z. immersa. Filaments 1-1200" in dia-
meter, joints about half as long again;
i transverse processes very thick, filled by the
large and globose spore (Hass. /. c. pi. 39.
fig. 3; Kiitz. I c. v. pi. 12. fig. 5).

Z. compicua. Filaments 1-1440 to
1-1080" in diameter, joints equal or twice
as long ; transverse processes long, ventri-
cose in the middle, where they enclose the

meter, joints three times (more rarely five
j times) as long; transverse processes short

ZYGNEMACE.E.

[ 828 ]

ZYGODESMTJS.

and filled by the globose spore (Hass. I. c.
pi. 39. fig. 6 ; Kiitz. I c. v. pi. 11. fig. 4).

Z. Ealfsii. Filaments 1-1920 to 1-1440"
in diameter, joints three or four times as
long; transverse processes very much dilated
in the middle, containing an elliptical spore,
with the long axis at right angles (Hass.
I c. pi. 39. figs. 4, 5 ; Kiitz. /. c. v. pi. 11.
fig. 2).

Z. pectinata. Filaments 1-660" in dia-
meter, joints equal or a little shorter; cell-
contents transversely bipartite, more fre-
quently radiato-dentate, pectinate, dull
green (Kiitz. /. c. v. pi. 14. fig. 4 ; Eng. Hot.
pi. 1611 ?). Possibly this is only a state of
Z. cruciata with the spores in the transverse
processes ; if so, the subdivision above indi-
cated cannot stand.

BIBL. Hassall, Alga, 160, pis. 38, 39
(Tyndartdea) ; Kiitz. (Zygnema and Zygo-
gonium, in part), Tab. Phyc. v. pis. 11-17,
'Sp. Alg. pp. 444, 445; Kabenh. Alg. iii.
248 ; Cooke, Alga, 1882.

ZYGNEMA'CE^(P1.9.figs. 16-28).— A
family of Oonfervoid Algse, consisting of
plants composed of articulated cylindrical
filaments, the cells of which often have the
green contents arranged in elegant patterns.
The principal mode of reproduction, whence
the family takes its name, is by CONJUGA-
TION, followed by a mixture of the entire
contents of the united cells, and their con-
version into a spore. Other phenomena
occur in some instances, such as the produc-
tion of ciliated zoospores, and small spore-
like bodies with a dense spinulose coat
(asteridia) ; but these appearances are not
yet thoroughly understood (see SPIROGYRA
and MOUGKEOTIA).

The British Genera are :—

Spirogyra. Filaments simple, with the
green contents arranged in one or more
spiral bands upon the cell- wall. Conjuga-
tion normally by transverse tubular pro-
cesses ; spores formed in one of the parent
cells (or occasionally in both).

Zygnema. Filaments simple, with the
green contents arranged in two globular or
stellate masses in each cell. Conjugation
by transverse processes ; spores formed in
one of the parent cells, or in the cross
branch.

Zygogonium. Filaments simple, or slightly
branched, with the contents diffused or
arranged in two transverse bands. Conju-
gation by transverse processes ; spores glo-
bose, formed in the cross branches, or in
blind lateral pouches without conjugation.

Mesocarpus. Filaments simple, with the
contents diffused. Conjugation by trans-
verse processes, from which the filaments
become recurved ; spores in the dilated
cross branches.

Staurocarpus. Filaments simple, with
the contents diffused (or rarely in monili-
form lines). Conjugation by transverse
processes, from which the filaments become
recurved ; spores (or sporanges) square or
cruciate, in the dilated cross branches.

Mougeotia. Filaments simple, soon bent
at intervals, contents mostly diffused, some-
times in several serpentine lines. Conjuga-
tion by the inosculation of the filaments at
the convexity of the angles; spores not
satisfactorily known.

Thwaitesia, Montagne, resembles Zygnema
in its stellate cell-contents ; but the spore
formed in one of the parent cells divides
into four portions (perhaps not distinct from
Zygnema).

Craterospermum, nearly resembling
Staurocarpus and Mougeotia, but with the
spore and the short tube in which it is con-
tained subconstricted in the middle.

Pleurocarpus. Simple filaments, with
diffused contents, the conjugation taking
place between adjacent cells of the same
filaments, by means of a short arcuate tube ;
spore globose, in the tube.

Rhynchonema, Kiitzing, has spiral cell-
contents like Spirogyra, but conjugates like
Pleurocarpus, by an arched tube connecting
adjacent cells of the same filament.

BIBL. Kiitzing, Spec. Alg., Tabul. Phyc. ;
Braun, Alg. Unicell. 60 ; Rabenh. Alg. iii.
110 ; Cooke, Alga, 1882.

See also the genera.

ZYGOC'EROS, Ehr.— A genus of Dia-
tomacese. Detached frustules of Bn>-
DULPHIA ?

BIBL. Ehrenberg, Abh. Berl. Ak. 1839,
131 ; Kiitzing, Bacill 138, and Sp. Alg. 139 ;
Eabenh. Alg. i. 310.

ZYGODAC'TYLA, Brandt.— A genus
of Campanulinidae (Hydroid Zoophytes).

Char. Capsules with an operculum formed
by many convergent and acuminate seg-
ments; polypes cylindrical, tentacles
webbed below; reproduction by free me-
dusiform gemmae.

Z. vibrina, Ilfracombe. (Hincks, Brit.
Zooph. 191.)

ZYGODES'MUS, Corda.— A genus of
Sepedoniei (Hyphomycetous Fungi). Z.
fuscus occurs upon bark of fallen branches.
Berkeley thinks it possibly may be a form

ZYGODON.

[ 829 ]

ZYMOMES.

of some Thelephoroid Fungus. Currey has
shown that Corda's figure (fig. 812) is not
completely accurate, since he finds the

Fig. 812.

Zygodesmus fuscus.
Magnitied 400 diameters.

points at the apex of the fertile pedicels
each crowned by a spore j and the normal
number of sterigmata is probably four, so
that the structure would resemble a basi-
dium of Hymenomycetes. The above figure
is after Corda.

BIBL. Berk. Crypt. Bot. 298; Currev,
Micr. Jn. v. 126. "

ZYG'ODON, Hook, and Taylor.— A genus
of Orthotrichaceous Mosses, deriving its
name from the yoking of the teeth in pairs ;
the species are mostly found in mountainous
districts and rarely in fruit.

ZYGOGO'NIUM, Kite.— A genus of
Zygnemaceae (Confervoid Algae), consisting
of filamentous plants, growing on damp
ground or in water, green or yellowish
when fresh, purple or brownish when dry.
Kiitzing includes here all HassaU's species
of Tyndaridea (ZYGNEMA) which produce
the spore in the cross branch.

Z. ericetorum, Kiitz. Filaments 1-2160
to 1-1440" in diameter, joints as longer half
as long again, cylindrical or torulose (fila-
ments sometimes slightly branched). Con-
jugation rare, apparently mostly 'chain-like,'
from one cell to the next in the same fila-
ment. Contents green when growing in
water, purple when growing on wet heaths
(Hass. pi. 41; Greville, Sc.Crypt. Fl. pi. 261.
fig. 1). Conferva ericetorum, Dillw.

See ZYGNEMA.

BIBL. Hassall, /. c. ; Greville, /. c. ; Kiit-
zing, Sp. Alg. 445, Tab. Phyc. v. pi. 10 ;
Eng. Bot. pi. 1553 ; Eabenh. Alg. iii. 251.

ZYGOMYCETES.— A group of Fungi,
in which conjugation takes place, corre-
sponding to the Conjugatae of the Algae, as
in the Mucorini &c. (Brefeld, Schimmel-
pilze, 1872 ; V. Tieghem, An. Sc. N. 5. xvii.;
Sachs, Bot. 268.)

ZYGOSEL'MIS, Duj.— A genus of In-
fusoria, of the family Euglenia.

Char. Form variable j movement effected
by two flagelliform filaments, incessantly in
action.

Z. nebulosa (PI. 32. fig. 23). Body colour-
less, sometimes globular, at others variously
expanded so as to become pyriform or
top-shaped, turbid from the presence of
numerous granules. Freshwater; length
1-1100".

BIBL. Dujardin, Inf. 369; Kent, Inf.
417.

ZY'GOSPORE or AUXOSPORE. — The
result of the union of conjugating Algae.

ZY'MOMES =MICROZYMES.

THE END.

I'UINTED BY TAYLOR AND tKANCIS, KED LION COURT, FLEET STREET.

THE

MICROGRAPHIC DICTIONARY;

A GUIDE TO THE EXAMINATION AND INVESTIGATION

OF THE

STRUCTURE AND NATURE

OF

MICROSCOPIC OBJECTS.

BY

J. W. GRIFFITH, M.D., &c.,

MEMBER OF THE ROYAL COLLEGE OF PHYSICIANS ;
AND

ARTHUR HENFREY, F.R.S., F.L.S., &c.,

PROFESSOR OF BOTANY IN KING'S COLLEGE, LONDON.

FO UR TH EDITION.

EDITED BY

J. W. GRIFFITH, M.D. &c.;

ASSISTED BY

THE REV. M. J. BERKELEY, M.A., F.R.S., F.L.S.,

AND

T. RUPERT JONES. F.R.S., F.G.S.,

LATE PROFESSOR OF GEOLOGY, SiAFF COLLEGE, SANDHURST.

ILLUSTRATED BY FIFTY-THREE PLATES AND EIGHT HUNDRED AND EIGHTEEN WOODCUTS,
CONTAINING FIGURES OF 2680 OBJECTS.

VOL. II.— PLATES.

LONDON :

JOHN VAN VOORST, PATERNOSTER ROW.

MDCCCLXXXIII.

PRINTED BY TAYLOR AND FRANCIS,
11E1) LION COURT, FLEET STREET.

ALEKR A FLAMMAM.

DESCRIPTION OF PLATES.

The diameters which each object is magnified, are expressed in the Plates by small
numbers placed beneath the object.

PLATE 1.— Test-Objects.

Figure

1. Hairs of the larva of the so-called Dermestes lardarius, viewed in balsam.

2. Hairs of the common bat (Vespertilio pipistrellus), in balsam, a, 6, coloured

hairs ; r, a white hair.

3. Hairs of mouse (Mus musculus), in balsam.

4. Pits of coniferous wood, common deal (Abies excelsa), viewed dry.

5. Mucus- (or salivary) corpuscles, seen under different powers.

6. Scales of Lepisma saccharine^ dry.

7. Scale from the wing of Morpho Menelaus, dry.

8. Scale from underside of wing of common clothes-moth (Tinea pellionella), dry.

9. Scales of Hipparchia janira. a, dry, and by oblique light; 6, in balsam, by

direct light; c, dry, after Schacht.

10. Didymohelix ferruginea, under different powers ; £>, with imperfect correction

or adjustment, c with perfect correction and adjustment ; c£, separate fibres.

11. Didymopriiun Borreri, empty cells.

12. Scales of Podura (Lepidocyrtus), under different powers, dry ; a, 220 diameters :

c, portion of scale — left hand, three markings as seen when the adjustment
of the object-glass is correct and the markings in focus ; right hand, showing
the markings dividing when the adjustments are correct and the focus altered
the least possible either way.

13. 'Pygidium of flea.

14. Frustule of Grammatophora manna (diagram), a, front view ; 6, side view.

15. Frustule of Grammatophora subtilissima (diagram). a} front view ; 6, side view.

16. Pleurosigma angulatum ; dry valve showing the dots.

17. Pteurosigma attenuatum; dry valve showing the lines.

18. Pleurosigma elongatum ; dry valve showing the lines.
1(J. Bacillus subtilis.

20. Bacterium termo.

PLATE 2. — Adulterations.

Figure
1.

2-11

4.

5.

7. |1

ali

9.
10.

11.
12.

13.
14.

15. p

16. 5

17. Si
SI

18. p

19. ||

Tea. a, point of leaf ; 6, under surface, with stomata and hairs ; c, epi-
dermis of midrib with raphides ; d, sclerogen cell from inside the
leaf.

ISloe. a, point of leaf ; 6, upper surface, showing hairs and striated
parenchyma.
Elder, a, point of leaf ; 6, upper surface ; c, under surface of leaf, with
sinuous striated cells and glandular hairs.

Cocoa, a, epidermis of husk ; 6, cells containing mucilage and raphides ;
c, hexagonal cells beneath the mucilage layer ; d, parenchymatous
granular cells, forming the inner layer of husk ; e, endosperm-cells
containing starch -grains.

Coffee, a, prosenchymatous cells of investing membrane of berry ;
6, thick-walled cells of endosperm, containing oil-globules.

Chicory, a, laticiferous vessels ; 6, pitted tissue ; c, cellular tissue.
Acorns, a, portion of husk ; b, cells of endosperm filled with starch.

Carob or locust-beans, a, 6, characteristic tissues in pod ; c, wedge-
shaped, and d, sphaerenchymatous cells of bean containing dark nuclei.

Date-stones. Sclerogen-cells of albumen.

Figs. «, laticiferous tissue ; 5, cellular tissue ; c, a hair ; cZ, woody
L tissue ; e, sphaeraphides ; /, characteristic tissue in fig-seed.

Mustard, a, b, c, tissues in the husk ; d, substance of the seed con-
sisting of granular matter and oil-globules.

f Pepper, a, 6, c, characteristic tissues in the husk ; d, cells containing
starch-granules.

J Cayenne Pepper, a, very characteristic tissue ; b, skin.

I Linseed. «, epidermis ; 6, c, second and third tissues ; d, endosperm
with oil-globules.

^Rice-husk, a, chief tissue of husk ; 6, the same broken up.

C Tobacco. Epidermis of under surface of leaf, with glandular hairs.

Dock. Epidermis of under surface of midrib, showing unicellular twisted
I hairs.

] Rhubarb. Epidermis of leaf, showing short unicellular pitted hairs.

| Coltsfoot. Epidermis of leaf, showing peculiar jointed hairs with long
^ whip-like appendages.

PI. 2.

London . John Van Voorst

PLATE 3.— Algae.

Figure

1. Agonium centrale.

2. Aphanocapsa virescens.

3. Aphanothece microscopica.

4. AmpTiithrix papillosa.

5. Aster oihrix Pertyana.

6. Chamcesiphon confervicola.

7. Ohroolepus aureum, b, the zoospores escaping.

8. Ccelastrum Naeyelii.

9. Ooniophytum Thompson!.

10. Craterospermum Icetevirens.

11. DictyospTicerium Ehrenbergii.

12. Microcystis progenita.

13. Polyedrium spinosum.

14. PTiysodictyon graniforme.

15. Pilinia ramosa.

16. Schizoclilamys gelatinosa.

17. Schizomeris Leibleinii.

18. Protoderma viride.

19. Prasiola calophyUa.

20. Spermosira litorea.

21. Sphcerotilus natans.

22. Sorastrum spinosum.

23. Spondylomorurti quaternarium.

24. Pleurocarpus mirabilis.

25. Stiehococcus bacillaris.

26. Synechococcus ceruginosus.

27. Zygogonium ericetorum.

28. Ghcetoococcus violaceus.

29. Palmodictyon viride.

30. Botryococcus Braunii.

31. Pdlmodactylon varium.

32. Bulbotrichia botryoides.

ALGAE

PI 3

.11 . I

• • ij'/iiM/
e~ • ' *

London: John Van Voors t .

PLATE 4.-— Algas Florideae.

Figure

1. Sporochnus pedunculatus. a, portion of branch ; ft, receptacle ; c, spores and

filaments.

2. Dictyota dicTiotoma. a, portion of frond ; ft, sorus ; c, section of the same with

spores.

3. Poly ides rotundus. a, frond with warts ; 6, favellidia from wart ; c, section

of frond and wart ; d, spore.

4. PhyllopTiora rubens ; 6, spores ; c, a nemathecium ; e£, filaments from the same.

5. Delesseria sanguinea ; ft, spores ; c, a tetraspore ; d, capsule ; 0, branch with

coccidia.

6. Nitophyllum punctatum ; &, a tubercle ; c, a tetraspore ; rf, spores.

7. Microcladia glandulosa ; 6, favella ; c, tetraspore ; d, branch with favella.

8. Rliodymenia Palmetto, ; 6, portion with sorus ; c, tetraspores ; d, coccidium.

9. Dasya arbuscula. a, portion of frond ; 6, branchlet with stichidia ; c, a cera-

midium.

10. Plocamium coccineum ; 6, branch with tubercles ; c, branch with sporophylls ;

d, tetraspore ; e, spore.

11. Rytiphlcea pinastroides ; 6, branch with ceramidia; c, stichidium; d, cera-

midium.

12. Nemaleon multifidum. a, spermatozoa adherent to trichogyne ; 6, antheridia ;

c, carpogon.

13. Odonfkalia dentata \ b, stichidia ; c, ceramidia ; c?, tetraspore ; e, spore.

14. Sphcerococcus coronopifolius ; 6, portion with tubercles ; c, a tubercle ; t^, spores.

15. Bonnemaisonia asparayoides ; b, portion with ceramidia ; r, ceramidium ;

d, spore.

16. Ptilota plumosa ; 6, c, favella ; d, tetraspore.

17. Gigartina acicularis ; b, c, tubercles with favellidia.

18. Naccaria Wigghii b, swollen ramuli with spores ; c, filaments with spore.

19. Bryopsis plumosa ; 6, portion of branch magnified.

20. Polysiphonia fastigiata ; 6, portion magnified.

21. Catenella opuntia. a, nat. size; 6, magnified 10 diam. ; c, tetraspore.

ALG& FLORIDE/E .

PI.*.

1 onion .- John Van "Vo or s t .

PLATE 5. — Unicellular Algae, etc.

Figure

1. Hydrocytium acuminatum. a, young plant ; 6, more advanced ; <?, older stage, with

the gonidia divided ; d, cell about to burst ; e} cell burst and discharging zoospores.

2. CJiaracium Sieboldii. a, b, c, successive stages of young plant ; d, mature cell dis-

charging its zoospores.

3. Sciadium arbuscula. a, young plants, the right-hand one setting free the gonidia of

the second generation ; 6, an older plant with an umbel of secondary cells, some
discharging their gonidia of the third generation ; c, part of an umbel of cells from
the last generation of a family, the gonidia being discharged as free zoospores.

4. Chlorosphcera Oliveri. a, perfect plant ; 5, a plant dividing into two ; e, the same with

the two new cells discharged from the parent.

5. Apiocystis Brauniana. a, perfect plant ; 6, zoospore ; c, germinating plant from a

zoospore.

6. Codiolum gregarium. a, young plant ; b, nearly mature.

7. Chytridium Olla upon an (Edogonium. a, a, Chytridia burst and discharging their

zoospores ; 6, a cell not yet open.

8. Pythium entophytum on Chlorosphcera. a, group, partly mature ; 6, side view of a

single cell perforating the cell-wall of the Chlorosphcera, and with its neck opened,
discharging the contents.

9. Clathrocystis ceruginosa. a, b, c, fronds in successive stages of growth, the natural

colour ; d, a frond dried ; e, highly magnified fragment, showing the minute cells
imbedded in the gelatinous frond.

10. Pandorina Morum. a, side view of active form with sixteen gonidia ; 6, side view of

larger form with thirty-two gonidia ; c, end view of a; d, form with crowded
gonidia after fertilization, the cilia lost ; e, the same more advanced, having lost the
gelatinous common envelope, and the cell-contents red ; f} a single encysted goni-
dium (resting-spore) from e, more magnified ; g, side view of a gonidium with the
contents becoming converted into spermatozoids ; h} a single spennatozoid.

11. Ophiocytium ma/us, in different stages of development.

12. Spore-formation of Vaucheria sessilis. A, the sporange s, and the antheridiurn a, not

yet open ; B, both open, the epoch of fertilization ; C, decaying filament with ripe
spore.

18. Fragment of a filament of (Edogonium tumidulum, consisting of antheridial cells, one
discharging a spennatozoid.

14. Fragment of (E, ciliatum, consisting of parent cells of androspores, one of which is

escaping.

15. Fragment of CE.gemelliparum, male plant, consisting of antheridial cells, some bursting

to discharge their twin spermatozoids.

16. Sporange with sessile dwarf male plant of (E. ciliatum.

17. The same older, the dwarf male plant a having burst and discharged the spermato-

zoid which has entered the sporangia! cell or oogonium.

18. Spermatozoids of (E. ciliatum.

19. A dwarf male plant of (E, ciliatum, discharging an androspore from its large basal cell.

20. Filament of (E. Braunii. a, a, dwarf male plants, sessile on the filament ; 6, 6, ferti-

lized spores in the sporangial cells.

21. Ripe spore of CE ciliatum.

22. Gemmation of the resting-spore of Bulbochate intermedia, a, ripe spore ; b, the same

enlarged ; c, the contents dividing ; c7, the contents converted into four ciliated
zoospores.

UNICELLULAR ALOE

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ELATE 6.— Arachnida.

Figure

1. Acarus (Tyroglyphus) domesticus (cheese-mite), a, labium and mandibles ; b, hair ;

g, labium ; », end of leg.

2. Acarus longior.

3. Anystis ruricola. a, palp ; b, mandible of. (See PL 50. fig. 4.)

4. Epidermis of Epeira dmdema. 5. Epidermis of a Dermanyssus.

6. Mandibles of Epeira.

7. Mandibles &c. of male Tegenaria. a, b, mandibles j c, palpi ; d, maxillae ; e, labium.

8. End of leg of Epeira. a, b, hairs of the same.

9. Lung-plates of Epeira ; 9 b, piece more magnified.

10. Spinneret of Tegenaria domestica. a} two separate spinning-tubes, the right-hand one

from Epeira, the left-hand one from Tegenaria.

11. Portion of cobweb of Epeira. 12. Epidermis of Arrenurus.

13. Arrenurus viridis, female, dorsal view, a, palp ; c, under view of male, showing round

mouth with hood and first two joints of palpi, the coxae, two stigmata and two gra-
nular plates, anal orifice and penis.

14. Atax histrionicus. a, mandible ; b, palp ; c, under view, with labium, coxae, and genital

plates.

15. Hypopus muscarum. 16. Sarcoptes scabiei, under view, female.
18. Psoroptes equi, under view. 19. Ixodes Dugesii, from above.

20. Ixodes Dugesii, anterior portion, from above, a, dorsal plate ; b, basilar piece of

support of rostrum ; c, palpi, between which part of mandibles is visible.

21. Ixodes Dugesii, side view of palp.

22. Ixodes Dugesii, basilar piece from above, a, dotted lines indicating first joint of man-

dibles (b) seen through support ; c, movable toothed claw.

23. Ixodes Dugesii, sixth and seventh joints of leg, with claws and caruncle.

24. Dermanyssus avium, from beneath; a, labium of male, compressed, with palp (*) and

mandible (f) ; b, mandible of female ; c, leg.

25. Uropoda vegetans. a, mandible j b, its end more magnified ; c, sixth and seventh joint

of leg in side view.

26. Gamasus coleoptratorum, from above, a, end of leg ; b, body from beneath ; c, mandible.

27. Limnochares aquatica. a, under view of labium and palpi ; b, side view of labium ;

c, tarsus j d, scaly plate supporting eyes ; e, two posterior coxse of one side only ;
ff rostrum protruded, with palpi and anterior coxae, trochanters and femora of one
side only.

28. Eylais extendens. a, mouth with its hood, and first joint of palps; b, palp ; c, end of

mandible, with hook ; d, under view of body, showing mouth, hood, and one palp, two
groups of anterior coxae with intervening genital orifice and two stigmata, posterior
coxae, anal orifice, and two other stigmata.

29. Hydrachna globula. a, under view, showing rostrum and palps, coxae, heart-shaped

genital plate and anus; b, mandible ; c, rostrum or labium, with a palp; d, palp of
larva ; e, end of leg ; /, nymphs adherent to Nepa.

30. Diplodontus scapularis. a, labium with palp seen from beneath ; b, mandible.

31. Bdella longicornis. b, mandible ; a, end, more magnified ; c, mandible of Bd. ccerulipes.

32. Tetranychus glaber. a, end of leg, front view, b, side view ; c, palp ; d, mandible.

33. Megamertis celer. a, labium ; b, palp ; c, mandible of Megamerus roseus.

34. Pachygnathus velutinus. a, palp ; b, end of leg ; c, mandible.

35. Tetranychus cristatus, vel lapidum. a, labium of Raphignathus ruberrimus with palp

and mandibles in situ ; b, mandible of same.

36. Smaris papillosa, from above, a, mandible.

37. Trombidium phalangii. a, pa]pi ; b, mandible.

38. Trombidium (Leptus) autumnale, from above. 39. Pteroptus vespertilionis, from above.
40. Trombidium cinereum. a, labium with a palp ; 6, tarsus ; c, plume of the labium

more magnified ; d, a mandible.

42. Demodex folliculorum, from beneath.

43. Demodex folliculorum, anterior portion from above, a, palps ; b, maxillae ; c, labrum ;

d, tubercles.

44. Scirus (Bdella) elaphus, side view, a, end of mandible.

ARAGHN1DA.

PLATE 7.— Confervoidese.

Figure

1. Chlorococcum vulgare, Grev. a, groups in natural condition ; b, an isolated cell show-

ing the granular contents ; c, dividing cells treated with sulphuric acid and iodine.

2. Protococcus viridis, nob. a, groups of cells, the upper one with eight in a linear series ;

those to the right with the contents dividing into numerous gonidia (?) ; 6, zoospores
set free from the cells by the solution of the cellulose membrane ; c, an isolated cell
dividing and about to set free its contents as two zoospores ; d, resting-cells with a
thick coat and reddish contents ; e, a zoospore with the cilia cast off'; ff a zoospore
with imperfect or retracted cilia ; g, remains of a zoospore left on a glass slide for
twenty-four hours.

3. Palmetto, cruenta, Br. a, patch of the jelly with single cells, and dividing and divided

pairs j b, similar cells without the gelatinous layer, the smaller granules similar to
those seen in the jelly of a ; c, cells treated with sulphuric acid and iodine, showing
the cellulose coat and granular contents ; d, diagram indicating the relative dimen-
sions of the cells of Palmetto, nivalis,

4. Glceocapsa polydermatica, Ktz.

5. a, b, c, Sarcina ventriculi, Goodsir.

6. Coccochloris Brebissonii, Ktz. «, group of cells, some dividing within their cell-coat ;

6, a linear group; c, a pair of cells conjugating; d, conjugated cells encysted and
passing into the resting stage.

7. Urococcus Hookerianus, Berk.

8. a, b, Hydrurus Ducluzelii, Ag.

9. Botrydina vulgaris, Ktz. a, 6, c, d, successive stages of growth.

10. Tetraspora gelatinosa, Ag. Four parent cells producing biciliated zoospores, imbedded

in the gelatinous frond.

11. Gonium pectorale, Mull, a, perfect frond; 6, the same seen edgewise; c, a single

zoospore.

12. Gonium tranquillum, Ehr.

13. Glosocapsa ampla, Ktz.

14. a, 6, Volvox globator ?, forms related to Syncrypta and Eudorina of Ehrenberg.

15. Spirulina oscillarioides) Turp. ?).

16. Spirulina Jenneri, Ktz.

17. «, Bacterium termo j 6, B. catenula ; c, B. punctum ; d, B. triloculare ; e, B. lineola ;

/, Spirillum tenue ; g, Sp. undula.

18. Bacillus subtilis.

19. Vibrio rugula.

20. Bacillus ulna.
20 a. Vibrio serpens.

21. Vibrio bacillus, probably Anabaina subtilissima, Kiitz.

22. Spirochceta plicatttis.

23. Spirillum volutans.
24-36. Volvox globator, L.

24. A perfect family.

25. With fully developed young within.

26. With yellow encysted (resting) spores.

27. Portion of the outer wall, with zoospores, some dividing.

28. Ditto, showing the cilia of the zoospores.

29. Ditto, a fragment after keeping some time in chloride of calcium, the portions around

each zoospore tumid.

30. The same seen obliquely, with the cilia.
81. Spore with the protoplasm dividing.

32. Ditto, more advanced.

33. An encysted spore with undivided contents.

34. An encysted resting-spore with yellow contents, probably a subsequent stage of 33.

35. Ditto, ruptured by pressure.

36. A similar resting-spore with conical processes on the outer coat (V. stellatits, Ehr.).

CONFERVOIDE/E

PI. 7

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PLATE 8.— Confervoideae.

Figure

1. Aphanizomenon flos-aquce, Morr. a, ordinary filaments ; 6, filaments with

spermatic cells ; c, filament with a vesicular cell (heterocyst).

2. Trichormus muscicola, n. sp. a, filament with vesicular cell; 6, ditto with

adjoining spermatic cells ; c and r?, fragments treated with acid to render the
membrane and contents distinct ; e and /, spermatic cells similarly treated.

3. Sphmrozyya elastica, Ag.

4. Gylindrospermum catenatum, Ralfs.

5. tSpermosira litorea, Harv.

6. Dolichospermum Ralfsii, Thwaites.

7. Nostoc commune, Vauch. a, ordinary filaments ; b, a single filament in its

gelatinous sheath ; c and d, fragments with a vesicular cell.

8. Oscillatoria autumnalis, Ag. a, fragments escaped from a sheath, 6.

9. Microcoleus repens, Harv. ; 6, fragments showing the single sheaths ; c, d, frag-

ments treated with sulphuric acid and iodine.

10. Lyngbya muralis, Ag.

11. Dasyglcea amorpha, Berk.

12. Sirosiphon ocellata, Berk.

13. Schizosiphon Warrenice, Caspary. a, tuft of filaments ; 6, c, fragments ; d, e,

decomposing sheaths.

14. Tolypothrix distorta, Kiitz.

15. Ainactis calcarea, Kiitz. ; 6, fragment showing the spiral sheath.

16. Euactis atra, Kiitz.

17. Schizothrix Creswettii, Harv.

18. Rivularia Boryana, Kiitz.

19. Scytonema Myochrous, Ag.

20. Arihronema cirrhosum, Hass.

21. Petalonema alatum, Berk. (Arthrosiphon Grevillii, Kiitz.). a, end of a filament ;

6, cross section.

22. Calothrix mirabilis, Ag., a ; ?>, junction of filaments.

con KI:K\ «MDI-; K

PI 8

I.

London ; Jolm Van Vbor

PLATE 9.— Confervoidese.

Figure

1. Monostroma bullosum, Thuret. a, fragment of frond, with some cells empty ;

b, ciliated zoospores from the cells ; c, zoospore germinating.

2. Ulva Lactuca, L. a, fragment of frond ; 6, small ciliated zoospores from ditto.

3. Ditto, a, fragment of frond ; b} ditto, with the cells nearly empty, showing the

orifices by which the zoospores escape ; c, large zoospore ; d, zoospores ger-
minating.

4. Enteromorpha claihrata, Grev. a, fragment of frond ; 6, zoospores from ditto ;

c, the same in germination.

5. Stigeoclonium protensum, Kiitz. a and 6, fragments of branched filaments,

b, emitting zoospores, c, c ; c£, germinating zoospores.

6. Ulothrix mucosa, Thur. a, 6, fragments of filaments ; c, zoospores ; d, e, ditto

germinating.

7. CEdogonium vesicatum, Link, a, fragment of a filament ; 6, ditto, breaking up

and emitting a zoospore ; c, zoospore with a crown of cilia ; d, e, germinating
zoospores ; /, membrane of a zoospore which has burst by a lid and discharged
small zoospores immediately after germination ; </, fragment of a filament with
one cell containing a resting-spore ; &, fragment of a filament in an abnormal
state, containing globular bodies ; i, germinating zoospore containing similar
globular bodies.

8. Chcetophora elegans, Ag.

9. A fragment of the same, emitting zoospores.

10. Conferva cerea, Dillw. a, fragment of filament, one cell of which has discharged

its contents in the form of zoospores, b.

11. Conferva floccosa, Thur. a, filament breaking up; 6, fragment of growing

filament ; c, zoospores.

12. Rhizoclonium obttisangulum, Kiitz.

13. Cladophora glomerata, Kiitz. a, filament with one fertile branch ; 6, apex of a

fertile branch discharging zoospores, c.

14. SpTiceroplea annulina, Kiitz. a, growing filament ; 6, filament with the con-

tents converted into spores.

15. Codium tomentosum, Ag. a, apex of clavate branch, with fertile cell ; b} zoo-

spores.

16. Staurocarpus gracilis, Hass. ; conjugating filaments.

17. Spirogyra quinina, Kiitz. ; growing filament.

18. Conjugating filaments, with spores.

19. Ditto, with the spores germinating.

20. Half-decomposed cell, with the contents converted into almost colourless bi-

ciliated zoospores.

21. Spore formed after conjugation.

22. The same shortly before germination.

23. A similar spore, with the contents converted into globular bodies.

24. a and 6, portions of a Spirogyra ? with the contents converted into spiny

globular bodies.

25. Spirogyra quinina, Kiitz. ; imperfectly conjugated celJs, with the contents con-

verted into globular bodies.

26. Spirogyra nitida ; cell with nucleus, n.

27. Spirogyra pellucida, Kiitz. ; cell with nucleus, w, and gelatinous outer coat, s.

28. Spirogyra nitida, Kiitz., half-decayed, the contents partly changed into globular

EKVOID&E.

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PLATE 10.— Confervoidese.— Crystals.

Figure

1. Cosmarium margaritiferum, Turp. ; conjugating pair with imperfect sporange.

2. Cosmarium botrytis, Bory ; conjugating pair with sporange, enveloped in jelly.

3 A. Closteriwn acerosum, Schrank. a, b, c, different stages of conjugation ;
d, frustules apparently produced from a sporange.

3 B. Closterium lunula, Miill. ; the contents converted into globular bodies.
4. Fragilaria penicillata, Lyngb. a and b, successive stages of conjugation.

5 A. Surirella bifrons, Ehr. ; conjugating pair, with intermediate large sporangial

frustule.
5 B. Surirella bifrons, Ehr., with the contents converted into globular bodies.

6. Epithemia turgida, Ehr. a, b, c, d, e, successive stages of conjugation producing

pairs of sporangial frustules.

7. Meloslra (Aulacosira) crenulata, Thw. «, filament with two conjugating pairs

of cells and perfect sporangial frustules ; 6 and c, large filaments produced
by sporangial frustules.

8. Melosira varians, Ag. a, small filament producing sporangial frustules by con-

jugation ; 6, large filament developed from sporangial frustules.

9. Orthosira Didciei, Thw. Successive stages of production of sporangial frustules

after conjugation.

10. Pinnularia viridis, Sm., with the contents converted into globular bodies.

11. Pediastrum granulatum, Ktz. «, a frond with most of the cells empty, three

full, and the contents of another swarming out as zoospores ; b, c, d, swarm of
zoospores producing a new frond.

12. Crystals of sugar of milk.

13. „ diabetic sugar.

14. „ indigo, sublimed.

15. „ oxalate of soda.

16. „ sulphate of lime.

17. „ phosphate of lime.

18. „ sulphate of strontia.

19. „ nitrate of soda.

20. „ allantoin.

21. „ antimoniate of soda.

22. „ protoxide of antimony.

23. „ butyrate of baryta, a, rapidly, b, slowly formed.

24. „ hydrofluosilicate of baryta.

25. „ sulphate of baryta, a, precipitated from concentrated, 6, from very

dilute solution.

26. „ carbonate of potash.

CQNFKKV<Mi»K.i;(' CRYSTALS

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PLATE 11.— Crystals.

Figure

1. «, brucia ; £>, sulphocyanide of brucia.

2. Cinchonine.

3. Sulphocyanide of cinchonine.

4. Narcotine.

5. «, b, Strychnine.

6. Sulphocyanide of strychnine.

7. Morphia.

8. Sulphocyanide of quinine.

9. Muriate of ammonia.

10. Purpurate of ammonia (murexide).

' 1 Nitrate of potash (ANALYTIC CRYSTALS).

13. Benzoic acid, a, crystalKzed from water; b, sublimed.

14. Lithofellinic acid.

15. Margarine.

16. Stearic acid ; a, margaric acid.

17. lodo-disulphate of quinine.

18. Hippuric acid.

19. Lactate of lime.

20. Lactate of zinc.

21. Succinic acid crystallized from water.

22. Creatine.

23. Creatinine.

24. Compound of creatinine and chloride of zinc.

Pl.ll.

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London. V<si.

G.JarTrian sc .

PLATE 12.— Crystals from Animal Secretions.

Figure

1. Uric acid, human, natural. «, rhombs, front view ; b, side view ; f, d, striated ;

0, rhombs with obtuse angles truncated ; /, twin crystals ; y, ditto ; 7i, hour-
glass crystals ; i, nucleated ditto ; k, I, m, n, o, aigrettes ; p, large dumb-
bell forms.

2. Uric acid, human, natural, a, front, 6, side view.

3. Uric acid, coloured artificially by murexide.

4. Uric acid, natural, a, front, 6, side view ; c, aigrette.

5. Uric acid, precipitated from solution in sulphuric acid by water.

6. Uric acid, rhombs, slightly acted upon with potash, showing spurious nuclei.

7. Uric acid, precipitated from gout-stones.

8. Uric acid of Boa, artificially precipitated, a — d, from solution in sulphuric

acid by water ; e — A, from solution in potash by muriatic acid.

9. Uric acid, precipitated from the excrement of the tortoise.

10. Uric acid, precipitated : — a, from the excrement of the clothes-moth ; 6, from

stag-beetle (Lucanus cervus).

11. Urate of soda and ammonia, a, spheres with nuclei and concentric rings, arti-

ficial ; 6, surface covered with radiating needles ; c, d, e, natural forms ;
/, </, artificial.

12. Urates of soda and ammonia. «, artificial urate of ammonia, deposited on

cooling of an aqueous solution ; 6, natural urate of soda, as composing the
chalky matter around gouty joints.

13. a, b, Urate of lime.

14. a, 6, Urate of magnesia.

15. Uric acid, precipitated by an acid from human urine.

CRYSTALS

PI. 22

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London

PLATE 13. — Crystals from Animal Secretions.

Figure

1. Various prismatic forms of the ammonio-phosphate of maguesia (triple phos-

phate), naturally formed in human secretions.

2. Feathery or penniform crystals of the same salt.

3. Stellate form of the same salt.

4. Minute imperfectly formed prisms of the same.

5. Cystic oxide.

6. Carbonate of lime deposited from water by standing.

7. Carbonate of lime from the urine of the horse, natural.

8. Carbonate of lime from the urine of man, natural.

9. Octahedra of oxalate of lime, as seen in water.

10. Octahedra of oxalate of lime, as seen when dried.

11. Ellipsoidal forms of oxalate of lime, natural.

12. Ellipsoidal constricted, or dumb-bell forms of the same, natural.

13. Crystals of oxalate of lime, prepared with acid.

14. Modified octahedra of the same salt, formed by double decomposition.

15. Crystals of bilif ulvine, natural, human.

16. Crystals of haomatoidine.

17. Crystals of urea.

18. Nitrate of urea; a, 6, slowly, c, rapidly formed.

19. Oxalate of urea.

20. Uroglaucine.

21. Cholesterine.

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PLATE 14.— Desmidiacese.

Figure

1. Hyalotheca dissiliens, front view.

2. Hyalotheca dissiliens, side or end view.

q 1

^ > Hyalotheca dissiliens, conjugating cells, with sporangia.

5. Didymoprium Orevillii, front view.

6. Didymoprium Grevillii, side view.

7. Desmidium Sivartzii, front view.

8. Desmidium Swartzii, side view.

9. Sphcerozosma vertebratum, front view.

10. Sphcerozosma vertebratum, side view.

11. Micrasterias denticulata, cell dividing.

12. Micrasterias denticulata, sporangium.

13. Micrasterias rotata.

14. JEuastrum verrucosum.

15. Euastrum oblonyum.

16. Euastrum didelta.

17. Euastrum didelta, cell free from contents

18. Cosmarium pyramidatum.

19. Cosmarium pyramidatum, empty cell.

20. Cosmarium crenatum.

21. Cosmarium margaritiferum.

22. Cosmarium tetraophthalmum.

23. Xanthidium armatum.

24. Xantkidium armatum, empty cell.

25. Xanthidium fasciculatum.

26. Staurastrum dejectum.

27. Arthrodesmiis convergent.

28. Staurastmm margaritaceum, front view.

29. Staurastmm margaritaceum, side view.

30. Staurastmm gracile, front view.

31. Staurastrum gracile, side view.

32. Didymocladonfurcigerus, front view ; fig. 56, end view.

33. Tetmemorus granulatus.

34. Tetmemorus granulatus, empty cell.

35. Tetmemorus Icevis, in conjugation.

36. Penium Brebissonii.

37. Penium margaritaceum, empty cell.

38. Docidium truncatum.

39. Docidium baculum.

40. Closterium lunula.

41. Closterium acerosum,

42. Closterium acerosum, in conjugation.

43. Closterium moniliferum.

44. Closterium didymotocum.

45. Closterium setaceum.

46. Closterium setaceum, in conjugation.

47. Ankistrodesmusfalcatus,

48. Pediastrum Boryanum.

49. Pediastrum granulatum, empty cell.

50. Scenedesmus quadricauda.

51. Scenedesmus obliquus.

52. Aptogonum desmidium, side view ; fig. 55, front view.

53. Scene.desmus obtusus, just after division.
24. Scenedesmus obtusus, ordinary state.

55. Aptogonum desmidium, front view ; fig. 52, side view.

56. Didymocladonfurcigerus', a, end view; fig. 32, front view.

57. Closterium Oriffithii.

58. „ _ „

59. Spirotcenia condensata.

lH-:SMim.\< K K- '- - •

Lcmdoru Jakn. Van. Yo ors t

J.Basire, sc.

PLATE 15.— Diatoinaceae.

The figures represent the prepared frustules or valves, except when otherwise stated.
Figure

1. Pinnularia nobilis, side view.

2. Pinnularia viridis, side view, with endochrome.

3. Pinnularia oblonga, side view.

4. Pinnularia radiosa, side view.

5. Pinnularia radiosa, front view.

6. Navicula cuspidata, side view.

7. Navicula cuspidata, front view.

8. Portion of the valve of a Navicula, showing the transverse rows of dots.

9. Navicula didyma, side view.

10. Pleurosigma balticum, side view.

11. Hoop of the same, side view.

12. Pleurosigma strigilis, side view.

13. Pleurosigma hippocampus, side view.

14. Pleurosigma acuminatum, side view.

15. Pleurosigma attenuatum, side view.

16. Pleurosigma attenuatum, front view.

17. Pleurosigma Spencerii, side view.

18. Pleurosigma lacustre, side view.

19. Pleurosigma littorale, side view.

20. Pleurosigma distortum, side view.

21. Pleurosigma fasciola, side view.

22. Pleurosigma macrum, side view.

23. Pleurosigma prolongatum, side view.

24. Pleurosigma tenuissimum, side view.

25. Pleurosigma formosum, side view.
2.6. Pleurosigma decorum, side view.

27. Pleurosigma obscurum, side view.

28. Pleurosigma speciosum, side view.

29. Pleurosigma strigosum, side view.

30. Pleurosigma rigidum, side view.

31. Pleurosigma elonyatum, side view.

32. Pleurosigma delicatulum, side view.

33. Pleurosigma angulatum, side view. «, with endochrome ; b, variety (3 ; c, variety y,

end of.

34. Pleurosigma quadratum.

35. Pleurosigma cestuarii.

36. Pleurosigma intermedium.

37. Pleurosigma, transversale.

38. Pleurosigma transversale.

39. Portion of valve of P. balticum.

40. Portion of valve of P. strigosum.

41. Portion of valve of P. angulatum (DIATOMACE^E).

42. Portion of valve of P. littorale.

43. Stauroneis phcenicenteron, side view.

44. Stauroneis pulchella, side view.

45. Stauroneis pulchella, front view.

46. Pleurosigma angulatum, showing the dots as pearls.

47. Isthmia enervis, portion of.

1 1 1. vrn.M A( -KJ-:

PL 15

Magnified

PLATE 16.— Diatomaceae.

Figure

1. Achnanthes longipes ; the front view of the frustules is visible.

2. Achnanthes longipes, side view, upper valve.

3. Achnanthes longipes, side view, lower valve.

4. Achnanthes exilis.

5. Achnanthidium microcephalum, side and front views.

6. Achnanthidium fleocellum, front and side views.

7. Amphipleura pellucida. a, side view of frustule ; ft, single valve ; c, Amphi-

pleura sigmoidea.

8. Amphiprora alata. a, side view ; ft, front view.

9. Amphitetras antediluviana. a, frustules united ; ft, side view ; c, front view ;

d, perspective view.

10. Amphora ovalis, front view ; 10 a, transverse section.

11. Amphora membranacea, front view of single valve.

12. Arachnoidiscus Ehrenbergii^ side view.

13. Arachnoidiscus Ehreribergii, portion of valve from the centre to the circumference.

14. Bacillaria paradooca. a, front view of conjoined frustules ; ft, side view ;

c, front view of single frustule. See also PL 18. fig. 17.

15. Biddulphia pulchella, front view, a, frustule dividing, front view.

16. Campylodiscus costatus, side view, ft, front view.

17. Cocconeis pediculus.

18. Cocconeis scutellum, single valve (side view).

19. Cocconema lanctolatum.

20. Cocconema lanceolatum, single vatye (side view).

21. Cyclotella operculata. #, side view; ft, front view.

22. Cyclotella Kutzingiana, front view.

23. Cymatopleura solea. a, side view ; ft, front view.

24. Cymatopleura elliptica, side view.

25. Denticula obtusa. ft, front view ; c, side view of single frustule ; c?, front view

of the same.

26. Diatoma vulgare, connected frustules. «, side view ; ft, front view of single

frustule.

27. Diadesmis confervacea. a, front view ; ft, side view.

28. Meridion constrictum. a, connected frustules forming a coil ; ft, front view of

single frustule.

29. Doryphora amphiceros. «, side view of frustule with endochrome; ft, front

view ; c, prepared single valve.

30. Eupodiscus argus. a, side view ; ft, front view ; c, fragment, more highly

magnified.

31. Eupodiscus sculptus^ side view.

32. Epithemia turgida. a, side view ; ft, front view.

33. Fragilaria capucina ; side view of frustule, front view of the same, and frus-

tules united into a filament.

34. Qomphonema acuminatum. a, filiform stipes ; ft, side view, c, front view of

frustule.

35. Grammatophora marina, connected frustules. ft, single frustule, front view ;

c, side view.

36. Himantidium pectinale, united frustules, front view, a, side view of single

frustule ; ft, side view of variety f> ; c, sporangial frustule.

London John Van Voorst

PLATE 17.— Diatomacese.

Figure

1. Hyalosira rectangula, front view of connected fmstules.

2. Isihmia enervis, front view.

3. Licmophora splendida. b, side view ; c, front view of single frustule.

4. LitJiodesmium undulatum. #, front view : &, side view.

5. Melosira nummuloides, front view.

6. Melosira varians, front view, a, side view.

7. Meridian circulare. a, fmstules united into a coil, front view ; b, side view of

single frustule.

8. Micromega parasiticum, natural size. 6, portion of a filament containing the

fmstules ; c, side view, d, front view of a frustule.

9. Nitzschia sigmoidea. a, side view ; 6, front view.

10. Nitzschia lanceolata. a, front view ; 5, separate valve ; c, side view of frustule ',

10 d, portion of valve, showing the dots.

11. Nitzschia longissima. a, side view ; b, front view.

12. Nitzschia reversa, front view of single valve.

13. Nitzschia. a, tcenia ; 6, acicularis.

14. Odontidium turgidulum. a, fmstules united, front view ; 6, single valve, side

view.

15. Orthosira Dickieii. a, front view ; b, side view.

16. Pododiscus jamaicensis. a, side view; 6, front view.

17. Podosphenia Ehreribergii. a, front view ; ?>, side view of single frustule.

18. Rhabdonema arcuatum. a, united frustules, front view; b, side view of single

frustule. See also PI. 18. fig. 69.

19 . RhipidopTiora paradoxa. 6, front view of single frustule ; c, side view of the same.

20. Striatella unipunctata. a, front view ; 6, the same ; c, side view.

21. Surirella gemma, a, side view ; 6, front view.

22. Surirella bifrons. a, front view ; 6, side view.

23. Synedra radians, a, attached frustules; b, side view of prepared frustule;

c, front view of the same.

24. Synedra fulgens. a, side view ; 6, front view of a prepared frustule.

25. Synedra capitata, side view.

26. Sphenosira catena. «, united frustules, front view ; b, side view of single frustule.

27. Tabellariaflocculosa. a, united frustules, front view ; 6, side view of single

frustule.

28. Tetracyclus lacmtris, united frustules, front view ; a, side view.

29. Triceratium favus. a, side view ; b, front view.

30. Tryblionella scutellum, side view.

31. Tryblionella gracilis, front view.

32. Tryblionella gracilis, diagram of transverse section.

DIATOMACF. I

1M.I7

PLATE 18.— Diatomaceae, etc.

Figure

1. Actiniscus tetrasterias.

2. Actiniscus pentasterias.

3. Actiniscus quinarius.

4. Actiniscus discus.

5. Actiniscus rota.

7. Anaulus scalaris.

8. Actinogonium septenarium.

9. Arthrodesmus minutus.

10. Amaroucium proliferum : a, nat. size ;

b, individual body magnified (TuNi-
CATA).

11. Amphicampa eruca.

12. Amphicampa mirdbilis.

13. Asellus vidgaris.

14. Aster ioneUa formosa.

15. Asteromphalos Beaumontii.

16. Biddulphia rhombus.

17. Bacillaria paradoxa (compare PI. 16.

fig. 14).

18. Bacteriastrum curvatum.

19. Bowerbankia imbricata : «, nat. size ; b}

portion magnified ; c} single body.

20. Botryllus polycyclus : a, nat. size ; b}

separate body (TUNICATA).

21. Coscinodiscus (Craspedodiscus) pyxidi-

cula.

22. Gammarus pulex.

23. Mastogonia : a, crux ; b, actinoptychus.

24. Mastogonia prcetexta.

25. Mastogonia hexagona.

26. Stephanodiscus Niagara.

27. Stephanodiscus lineatus.

28. Stephanodiscus sinensis.

29. Stephanodiscus dEgyptiacus.
29* .Stephanodiscus Bramaputrce.

30. Stephanogonia polygona.

31. Hercotheca mammillaris.

32. Syringidium bicorne.

33. Syringidium palcemon.

Figure

34. Biblarium castellum.

35. Biblarium compressum.

36. Biblarium compressum.

37. Biblarium elegans.

38. Biblarium elhpticum.

39. Biblarium emarginatum.

40. Biblarium emarginatum.

41. Biblarium strumosum.

42. Biblarium stella.

43. Biblarium speciosum.

44. Biblarium rhombus,

45. Biblarium linear e.

46. Biblarium lancea.

47. Biblarium glans.

48. Biblarium follis.

49. Stylobiblium clypeus.

50. Stylobiblium : a, b, clypeus ; c, divisum ;

rf, eccentricum.

51 . Halionyx undenarius.

52. Odontodiscus eccentricus.

53. Omphalopelta areolata.

54. Symbolophora acuta.

55. Symbolophora micrasterias.

56. Symbolophora pentas.

57. Systephania corona.

58. Systephania diadema.

59. Syndendrium diadema.

60. Auliscus pruinosus.

61. Dicladia antennata.

62. Dicladia bulbosa.

63. Dicladia capreolus.

64. Dicladia -capreolus.

65. Dicladia clathrata.

66. Periptera tetracladia.

67. Periptera capra.

68. Dictyolampi'a stella.

69. JRhabdonema arcitatwn; compound frus-

tule.

FOSSIL DIATOMACEJE,&*.

zso-300 duime&r^wiless otherwise, expressed,

P118

66

•i > n iW i

CJarrnan sc

PLATE 19. — DiatomaceaB and Entomostraca.

Figure

1. Acroperus nanus.

2. Acroperus harpce.

3. Alieutha depressa. a, first pair of legs.

4. Alona reticulata.

5. Alona quadrangularis.

6. Anomalocera Patersonii, male.

7. Anehorella uncinata. a, arms ; b, abdomen ; c, ovarian tubes.

8. Berkeleya fragilis. a, natural size ; 6, portion of a branch containing frustules ;

c, side view, d, front view of a single frustule.

9. Biddulpha aurita. Prustules undergoing division : #, hoop of original frustule,

to which two new halves (c) have been formed ; the hoop of the new frustules
is seen at b ; the hoop of the parent has separated from the two frustules d d,
which are perfectly formed, each with its new hoop.

10. Encyonema prostratum. a, frustules contained in a gelatinous tube, side view ;

6, front view ; c, separate frustules, side view.

11. Rhaphidoglcea micans. a, natural size ; 6, group of frustules ; c, single frustule,

front view.

12. Schizonema Dillwynnii. a, natural size ; £>, filaments containing frustules ; c,

front view, cZ, side view of frustule.

13. Zygoceros rhombus, a, front view ; 6, side view.

14. Syncydia salpa ; frustules immersed in a gelatinous mass.

15. Homceocladia anglica. a, portion of the natural size ; 6, part of a filament con-

taining two frustules ; c, front view, d, side view of a prepared frustule.

16. Dickieia alvoides. a, natural size ; 6, portion of frond containing frustules ; c,

d, /, prepared frustules, front view ; e, side view.

17. Frustulia saooonica ; frustules immersed in a gelatinous mass.

18. Gymbosira Agardhii. a, united frustules ; 6, front view, c, side view of pre-

pared frustules.

19. Sphenella vulgaris. a, front view ; 6, side view.

20. Spermatozoa of a Cypris.

21. Cetochilus septentrionalis, dorsal view.

22. Notodelpliys ascidicola, female.

23. Lepeophthirus pectorcdis, female.

24. Lerneonema spratta, female.

25. Macrothrioc laticornis, female.

26. Moina rectirostrist female.

27. Sida crystallina.

28. Nebalia bipes.

29. Polyphemus pediculus.

30. Evadne Nordmanni.

31. Peracantha truncata. a, superior antenna.

32. Pleuroxus trigonellus.

33. Terpsinoe musica : front view, PI. 25. fig. 10.

34. Podosira hormoides, front view.

35. Tessella interrupta, front view.

36. Nicothoe astaci. a, ovaries.

37. Cythere lutea. Poison-gland, a, and urticating organ, b.

DlATOMACEjC & ENTOMOSTRACA

PJ19

London John'Van Vjorst

PLATE 20.— Entomostraca.

Figure

1. Argulus foliaceus, seen from beneath, a, anterior, b, posterior antennae ; c,

rostrum ; d, suckers, representing the first pair of legs ; e, second pair of legs ;
/, four posterior pairs of legs.

2. Bosmina longirostris ; 2*, the same, natural size.

3. Branchipus stagnalis.

4. Camptocercus macrourus.

5. Cypris reptans ; 5 a, inferior antenna.

6. Canthocamptus minutus ; 6 a, inferior antenna; 6 &, first pair of foot-jaws

6c, second pair of foot-jaws.

7. Chydorus splicer icus.

8. Cyclops quadricornis, male, a, b, superior antennae

9. Cyclops quadricornis, female, a, superior, b, inferior antennae.

10. Cyclops quadricornis, inferior antenna.

11. Cyclops quadricornis, mandible; a, body; 6, serrated seta ; c, filaments of palp.

12. Cyclops quadricornis, first pair of foot-jaws.

13. Cyclops quadricornis, second pair of foot-jaws: 13 a, internal portion; 136,

external portion.

14. Cyclops quadricornis, first pair of thoracic legs.

15. Cyclops quadricornis, fifth pair of legs.

16. Cyclops quadricornis, recently hatched.

17. Cypris tristriata.

18. Cypris tristriata, superior antenna.

19. Cypris tristriata, inferior antenna.

20. Cypris tristriata, mandible.

21. Cypris tristriata, first pair of jaws ; a, basal plate ; b, branchial lamina.

22. Cypris tristriata, second pair of legs.

23. Cypris tristriata, first pair of legs.

24. Cypris tristriata, second pair of legs.

25. Cypris tristriata, lateral half of the abdomen.

26. Cythere inopinata.

27. Daplinella Wingii.

28. Daphnia pulex. a, superior antennae ; &, inferior antennae ; c, heart.

29. Daphnia pulex, first pair of legs.

30. DapTinia pulex, second pair of legs.

31. DapTinia pulex, third pair of legs.

32. Daphnia pulex, fourth pair of legs.

33. Daphnia pulex, fifth pair of legs.

34. DapTinia pulex, mandible.

35. Daphnia pulex, labrum.

36. Daphnia pulex, jaw.

37. Daphnia reticulata. a, ephippium.

38. Diaptomus castor.

39. Eurycercus lamdlatus.

ENTOMOSTRACA.

2

PI. 20.

G.J*rnvm sc.

LondoT) . John Va.n Voorst.

PLATE 21.— Entozoa.

Figure

1. Echinococcus veterinorum (hominis) ; 1 a, in the contracted state ; 1 b, hooks ;

1 c, d, f, in the expanded state ; 1 e, imperfectly developed individual.

2. Echinococcus veterinorum (liominis), cyst reproducing by external gemmation.

3. Cysticercus cellulosce, a, nat. size ; 3 b, C. fasciolaris, head of.

4. Anguillula fluvia tilis.

5. Anguillula aceti.

6. Anguillula tritici. a, b, ova ; c, mature individual ; <#, imperfectly developed

individual.

6 e. Dochmius (Anchylostomum) duodenalis, male; #, head of female; + , male,
t, female, nat. size.

7. Gyrodactylus auriculatus, 8 diameters.

8. Ascaris vermicularis ; 8 a, head; d, stomach; 0, oesophagus; g, anus; h, ovaries ;

k, oviduct.

9. Ascaris lunibricoides ; «, front view of head; 96, tail of male, with spicula ;

9 c, side view of head.
10. Ccenurus cerebralis, portion of a cyst,

12. Tcenia solium, head of, side view ; two of the suckers only are visible.

13. Tcenia solium, head of, front view ; all the four suckers are visible.

14. Tcenia solium, a single joint, injected, a, gastric (?) canals ; 6, vascular canals ;

c, testicular capsule ; d, spermatic duct ; e, oviduct ; the dark ramified organ
is the ovary.

15. Tcenia solium, ovum of.

16. Trichina spiralis, lying within its cyst, imbedded in muscle.

17. Trichina spiralis, removed from its cyst.

18. Trichina spiralis, internal organs.

19. Trichocephalus dispar, male.

20. Trichocephalus dispar, portion of the neck.

21. Trichocepl talus dispar, female ; 21 a, ovum.

22. Monostoma verrucosum, ovum of.

23. Tcenia variabilis, ovum of.

25. Gregarina sipunculi.

26. Gregarina sipunculi, with two enclosed cells.

27. Caudate pseudo-navicula, from the abdominal cavity of Sipunculus nudus.

28. Gregarina Sieboldii.

29. Young pseudo-navicula cyst of Gregarina scenuridis, from testis of Scenuris

variegata, consisting of loosely connected ovate cells, without an outer
envelope.

30. The same, with an outer envelope.

31. More advanced pseudo-navicula cyst of the same Gregarina, with two cells

containing rounded pseudo-naviculse.

32. The same, with elongated pseudo-naviculse ; the cyst has three cell-like bodies

on its surface.

33. The same with a single cavity, containing elongated pseudo-naviculaB.

34. Two Gregarince s&nuridis, adherent by their ends.

35. EchinorTiynchus anthuris, head, 25 diameters.

ENTOZOA

PI 21.

\

PLATE 22.— Fish-scales, etc.

Figure

1. Scale of sturgeon, perpendicular section. a, outer spongy portion ; 5, inner

laminated portion ; 1 e, transverse section of outer portion.

2. Skin of thornback skate (Raia clavata), viewed from above.

3. Large spine of skate, side view.

4. Portion of transverse section of large spine of skate (fig. 3 b).

5. Longitudinal section of tooth of a small spine of skate (fig. 2).

6. Scale of perch (Perca fluviatilis).

7. Perch-scale, portion of (fig. 6 a), more magnified.

8. Perch-scale, portion of (fig. 6 6), more magnified.

9. Scale of sole (Solea vulgaris).

10. Scale of roach (Leuciscus rutilus).

11. Scale of roach (Leuciscus rutilus*), portion of surface more highly magnified.

12. Scale of roach (Leuciscus rutilus}, perpendicular section.

13. Scale of minnow (Leuciscus phoxinus}.

14. Feather of finch ; shaft with medullary cells.

15. Feather of goose (Anser cinereus). a, pinna3 with hooks ; b, pinnae with teeth ;

c, barbs.

16. Separate pinnae, a, with hooks ; 5, with teeth.

17 1

' I Feather (downy), free barbs of.

18. J

19. Skin of eel (Anguilla vulgaris), with stellate pigment-cells, and indications of

subjacent scales.

20. Scale of eel (Anguilla vulgaris). 20 a, portion, more magnified.

21. Calcareous corpuscles from the same, left after red heat.

22. Scale of jack or pike (Esoce lucius).

23. Scale of dace (Leuciscus vulgaris).

25. Leech (Hirudo medicinalis), anterior sucker of.

26. Leech, jaw of, side view. a, b, teeth ; c, fibro-cartilagmous substance of jaw ;

d, pigment-cells.

27. Leech, jaw of, the free margin turned towards the observer.

28. Leech, teeth of. a, side view ; 5, front view.

29. Horn of cow. a, section parallel to surface ; 6, cells softened by potash ; d, con-

taining pigment ; e, perpendicular section ; /, cracks between lamina ; g, edges
of divided laminae.

30. Whalebone, longitudinal section.

31. Whalebone, transverse section.

32. Whalebone, longitudinal section of hair of.

33. Whalebone, cells of, resolved by potash.

34. Fish, crystals from scales of.

35. Muscular fibres of lobster (Astacus marinus).

36. Muscular fibrillae, various appearances presented by (p. 525).

37. Large spine of skate, outer portion of.

&t ,

M \

- fc>

PLATE 23.— Foraminifera, etc,

Figure

1. Miliola obesa (young or " Adelosine" condition).

2. Uniloculina indica. a, side view ; b, end view.

3. Biloculina ring ens.

4 a, b. Triloculina trigonula.

5. Quinqueloculina seminulum, a, b.

6 a, b. Quinqueloculina Brongniartii*

7. Spiroloculina planulata.

8. Hauerina compressa, a, b.

9. Articulina gibberula, a, b.

10. Vertebi'alina striata.

11. Peneroplis pertusus, a, b.

12. Spirolina austriaca, a, b.

13. Cornuspira foliacea, magn. 8 diameters.

14. Trochammina incerta, magn. 25 diameters.

15. Alveolina fustformis.

16. Alveolina rotella, a, b.

17. Orbiiolites complanatus, a, b. b, natural size.

18. Lituola difformis, side view, somewhat abraded.

19. Orbiculina adunca.

20. Valvulina austriaca.

21. Nubecularia rugosa, a, b.

22. Lagena lavis ; b, transverse section.

23. Entosolenia globosa, a, b.

24. Lagena striata (apiculate).

25. Lagena semistriata.

26. Lagena squamosa.

27. Lagena scalar if ormis.

28. Olandulina lavigata, a, b.

29. Nodosaria raphanus, var.

30. Marginulina raphanus.

31. Marginulina raphanus (inside of the shell).

32. Marginulina raphanus (sarcode, without the shell).

33. Dentalina communis.

34. Cristettaria simplex.

35. Vaginula badenensis, a, b.

36. Ch'thocerina quadrilatera, a} b.

37. Cristellaria cultrata, a, b.

38. Flabellina rugosa, a, b.

39. Frondicularia spathulata (fragment).

40. Polymorphina communis, a, b.

41. Polymorphina Orbignii (tubulosa).

42. Polymorphina oblonga.

43. Polymorphina compressa.

44. Uvigerina pygmcea.

45. Cassidulina Icevigata, a, b.

46. Bulimina pupoides.

47. Textularia cuneiformis, a, b.

48. Gaudryina pupoides, «, b.

49. Vidvulina gramen, a, b.

50. Bigenerina agglutinans, a, b.

61. Clavulina ( Valvulina) parisiensis, a} b.

52. Textularia annectens.

53. Dactylopora eruca.

54. Dactylopora reticulata.

65. Polystomella crispa, the body (sarcode) of.

56. Coccospberfca, a; coccoliths, ft, c, d; highly magnified.

rORAMINIFERA

Pi. 23 .

Tufferf'Afest del.

Lonbcm . John VITI Voorst

PLATE 24.— Foraminifera.

Figure

1. Orbulina universa.

2. Globigerina bulloides.

3. Ditto, seen by transmitted light, with air in the cells.

4. Sphceroidina austriaca.

5. Spirillina perforata.

6. Planorbulina Haidingeri, a, b.

7. Discorbina rosacea, a, b.

8. Patellina corrugata.

9. Truncatulina lobatula, a, b.

10. Planorbulina mediterranensis.

11. Pulvinulina vermicularis.

12. Planorbulina veneta (living).

13. Rotalia Beccarii, a, b.

14. Ditto ; sarcode, without shell.

15. Fusulina cylindrica, a, b, c.

16. Pulvinulina repanda, a, 6, c.

17. Cymbalopora Poyei, a, 6.

18. Nonionina crassula, a, 6.

19. Polystomella striato-punctata.

20. Polystomella crispa, a, b.

21. Nummulites radiata, a, b.

22. Nummulites acuta, section.

23. Operculina arabica, nat. size.

24. Ditto, enlarged horizontal section of portion.

25. Ditto, enlarged transverse section of part. }

26. Ditto, portion of fig. 25, highly magnified. J

27. Calcarina Spengleri.

28. Amphistegina Hauerina, a, b.

f<'< >K. \MiNlFER A

PI. 24.

'•MlVoOTSb

PLATE 25.— Fossils.

Figure

1. Mesocena octogona.

2. AsterompJialus HooTcerii, side view.

3. Hemiaulus antarcticus, front view.

4. Heliopelta Leeuwerihoeclcii, side view.

5. Asterolampra marylandica, side view.

6. SymbolopTiora trinitatis, side view.

7. Coscinodiscus craspedodiscus, side view.

8. Coscinodiscus craspedodiscus, half a valve.

9. Climacosphenia moniligera. a, side view ; b, front view.

10. Terpsinoe musica, front view : side view, PI. 19. fig. 33.

11. AmpTiipentas alternans, side view.

12. Bodies found in flint, nature doubtful (see PYXIDICFLA).

13. Pyxidicula major, front view.

14. Moss-agate, a, a, silicified fibres of sponge ; 6, gemmules ; c, branched fibre ;

d, spicula.

15. Crystalloids of coccolithic chalk, a, simple rings ; 6, radiately striated rings ;

c, disks.

16. Actinoptychus senarius. a, side view ; 6, front view.

17. Actinocyclus undulatus. a, side view; 6, front view.

18. Campylodiscus clypeus.

19. Dictyocha gracilis, oblique view.

20. Dictyocha gracilis, side view.

21. Dictyocha gracilis, front view.

Fossil bodies from flint, so-called Xanthidia, but consisting of the sporangia of
the Desmidiaceaj.

27.
28.

29. Vertical (radial) section of coal from Disco, consisting of Coniferous wood

(Finns}.

30. Transverse section of the same coal.

31. Splinter of the same.

32. Vertical section of silicified wood (Pinus) from Virginia.

33. Vertical section of silicified wood (Araucaria ?) from Australia. "

SSILS

del

.IftTJ- Si,

PLATE 26.— Fungi.

Figure

1. Vertical section of a leaf of black currant, infested with ^Ecidium yrossularice.

sp, spermogonia ; JK>, perithecia.

2. Sterigmata (si} and spermatia (sp) from the spermogonia of ^Ecidium euplwrbi&.

3. Ditto, from Radium berberidis.

4. Vertical section of a spermogonium of Radium berberidis.

5. Botrytis infestans, young plants growing out from a stoma of a potato.

6. Full-grown plants of the same. 6 a, spore of ditto.

7. Torula, growing in urine (not diabetic).

8. Grape-fungus, conidial form (Oidium Tucker i) as commonly found on the leaves

and fruits.

9-11. Conidia of the same, germinating.

12. Sporiferous form (Cicinobolus).

13. Spores from the same.

14. Hop-mildew, Erysiplie (Sphcerofheca) Gastagnei. a, Oidial form ; 6, b, form

resembling Cicinobolus ; c, d, Erysiphal form ; e, spores.

15. Fragment from the summit of a fertile filament of Penicillium glaucum.

16. Spores of ditto, a, two still united ; 6, one detached.

17. Section of a conceptacle of Cenangium fmxini, containing st, stylospores, and

s, spermatia.

18. Ergot of rye, Claviceps purpurea, Tulasne ; fruits sprouting from the ergot.

19. Vertical section of the head of one of the fruits, bearing conceptacles in its

periphery.

20 Vertical section of a conceptacle containing asci.

21. Asci removed from the same.

22. Spores from the interior of the asci.

23. Yeast-fungus (Torula cerevisice), large form at the bottom of liquid.

24. Ditto, minute form, appearing as a white mealy substance on the surface of

stale beer.

25. SpTiceria inquinans (a) with Stilbospora macrosperma (&) in the bark of an elm-

tree.

26. A portion of the common matrix separating the two, with the stylospores of

Stilbospora (b) above, and the asci of Sffhana («) below.

27. Spore of Stilbospora macrosperma.

28. Spore of Sphceria inquinans.

F1.26.

1 I

^ ^JiS^:-::^i^' •*

AHtnfrei.dtl

J.Bafire. ,

PLATE 27. — Fungi.

Highly magnified.
Figure

1. Part of hymenium of Agaricus trechispora, with sporophores, spores, and cysti-

dium. «, spore.

2. Sporophore with spores of Agaricus nebularis.

3. Fertile threads of Tremella mesenterica, with lobed sporophores and elongated

spicules, one of which bears a spore.

4. Threads of the same, bearing conidia.

5. Spores of Dacrymyces sebaceus, producing secondary spores.

6. Sporophore of Geaster rufescens, with its spicules and spores.

7. Sporophore of Cyathus striatus, with spores.

8. Sporophore of Rhizopogon luteolus, with spores.

9. Threads and cysts containing spores of Enerthenema elegans.

10. Germinating spore and amoeboid of Stemonitis cibtusata.

11. Spores springing from the wall of the perithecium in Hendersonia elegans.

12. Spores of Sporidesmium atrum.

13. Germinating pseudo-spore of Tilletia caries. a, further development of

anastomosing threads ; 6, the same producing a secondary spore.

14. Zoospore of Cystopus oandidus.

15. Thread with spores of Spondylodadium fumosum.

16. Peronospora curta.

17. Zoospore of Peronospora umbelliferarum.

18. ASCIIS and paraphysis of Peziza hydnicola ; a, conidia.

19. Stylospores of Oenangiwm fraocini ; a, spermatia of same.

20. Conidiiferous threads of SpTiceria cupulifera ; a, sporidia.

21. Mucar (AscopJiora} rhizopogonis, with an entire and ruptured vesiole with its

columella ; a, spores of same.

22. End of filament of male plant of Saprolegnia dioica.

23. Spermatozoids.

24. Oogonium of same.

25. Tip of male plant of the same, producing globular bodies filled with spermatozoids.

26. Young oogonium of the same, with antheridium attached.

27. Zoospore of Saprolegnia lactea.

FUNG]

PJ 27

J.Berfc I

PLATE 28.— Hairs, Fibres, Glands, &c, of Plants,

Figure

1. Cotton, a, normal condition ; 6, portion treated with sulphuric acid and iodine ;

c, a fragment of gun-cotton ; d, transverse section of cotton-fibre.

2. Flax, a, normal fibre ; b, portion boiled with nitric acid ; o, treated with nitric

acid, and afterwards with sulphuric acid and iodine.

3. Jute, a, normal fibre ; 6, c, portions boiled with nitric acid.

4. Coir (cocoa-nut fibre), bundle of fibres.

5. Ditto, a, 6, portions of fibres boiled with nitric acid.

6. Hemp, a, normal fibre ; 6, portions boiled with nitric acid.

7. Manilla hemp, a, normal fibres ; 6, fragment boiled with nitric acid,

8. Sting of Urtica urens.

9. Surface of the cuticle of Helleborus fcetidus.

10. Ditto of CaJcile americana.

11. Imbedded gland of Euta graveolens, vertical section.

12. Glands of Magnolia, seen from above.

13. Hair of Siphocampylus bicolor, the cuticle detached by sulphuric acid.

14. Glands of hop. «, side view ; &, from above.

15. Stellate body from the air-spaces in the leaf of NupJiar lutea.

16. Hair of Delphinium pinnatifidum.

17. Hair of Anchusa crispa.

18. Hair of Pelargonium.

19. Branched hair of Verbascum Thapsus.

20. Scale-like hairs from the seed of Gobcea scandens.

21. Annulated hairs from the seed of Ruellia formosa, in water; 6, detached cell-wall.

22. Spiral-fibrous hairs from the seed of Gollomia grandiftora, in water. 6, c, frag-

ments showing the cell-wall and free fibre.

23. Hair from the seed of a Sdlvia.

24. Hair from the seed of Acanthodium spicatum. £>, a fragment of a branch.

25. Chinese grass-cloth fibre, a, normal fibre ; 5, fragments boiled with nitric

acid ; c, afterwards treated with sulphuric acid and iodine.

26. Puya fibre, a, normal fibre ; 6, fragments boiled with nitric acid ; c, after-

wards treated with sulphuric acid and iodine.
26*. Stellate hairs from the epidermis of Deutzia scabra.

27. Stellate hair of ivy-leaf.

28. Stellate hair of Alyssum.

29. Horizontal stalked hair of Gfrevittea lifhidopTiylla.

30. T-shaped hair of garden Crysanihemum.

31. Eamentum or scale from a germinating fern.

32. Hair from the bulbil of Achimenes.

33. Hair from the corolla of Digitalis purpurea.

34. Hair from the corolla of Antirrhinum majus.

35. Branched hair from the epidermis of Sisymbrium sophia.

36. Forked hair from Capsella bursa-pastoris.

37. Branched hair of Alternanthera axillaris.

38. Gland of Dictamnus fraocinella.

Epidermis of Dictamnus fraxinella. a, 6, hairs ; c, gland vertically divided.

40. Glandular hair of Lysimachia vulgaris.

41. Glandular hair of ScropTiularia nodosa.

42. Glandular hair of Bryonia alba.

43. Scale of Beqonia 'platanifolia

44. Glandular hair of CfUia tricolor.

45. Vertical section of papilla of Mesem-

bryanthemum crystallinum.

46. Seta of a rose.

47. Tufted hair of Marrubium creti-

cum.

HAIRS. FIBRES.& GLANDS OF PLANTS

PL. 28

A.Henfrey.Del.

London . John Van Voors L.

R^M. Coll ing.

PLATE 29. — Hairs of Animals.

Figure

1. Human whisker, white ; air partly displayed from medulla.

2. Human hair, transverse sections.

3. Human hair, foetal, with imbricated scales.

4. Monkey, Indian (Semnopithecus}.

5. Lemur.

6. Bat, Indian.

7. Bat, Australian.

8. Mole (Talpa europcea).

9. Lion (Felis leo) ; a, by transmitted, 5, by reflected light.

10. Bear ( Ursus arctos).

11. Wolf (Cams lupus}.

12. Coatimondi (Nasua}.

13. Seal, Falkland-Island (Phoccena falklandica}.

14. Horse (Equus caballus).

15. Elephant (Elephas indicus), segment of a transverse section.

16. Pig (Sus scrofa).

17. Cheiropotamus.

18. Camel (Camelus bactrianus).

19. Dromedary (Camelus dromedarius).

20. Deer, moose- (Cervus alces).

21. Deer, musk- (Moschus moschiferus).

22. Wool, sheep (Ovis aries).

23. Sloth (Brady pus didactylus).

24. Armadillo (Dasypus sexcinctus).

25. Beaver (Castor fiber}.

26. Shrew (Anvphisorex rustwus}.

27. Mouse (Mus musculus}.

28. Ditto, treated with potash.

29. Guineapig (Cavla cobaya}.

30. Squirrel (Sciurus vulgaris}.

31. Rabbit (Lepus cuniculus}.

32. Sable (Mustela zibellina).

33. Mink-sable (Mustela lutreola).

34. Badger (Meles taxus}.

35. Chinchilla (Chinchilla lanigera},

36. Kangaroo (Macropus}.

37. Opossum (Didelphys virginiana}.

38. Ornithorhynehus paradoxus. a, entire hair ; 6, c, ^, and 38*, portions, more

magnified.

39. Crab (Cancer mcenas), from antenna of.

40. Spider (Lycosa saccata).

41. Spider (Mygale}.

42. Spider from South America.

HAIRS

London. J. Van Voorst

PLATE 30.— Infusoria.

Figure

1. Acineria incurvata, Duj.

2. Acineria acuta, D.

3. Acomia vitrea, D.

4. Acineta tvberosa, Ehr.

Sa.Podophryajixa, E. j 5 6, the same, or the Podophrya-Bt&ge of Vorticella ?

6. Actinophrys viridis, E.

7 a. Actinophrys Eichornii, E. ; 76, Actinophrys sol, E.

8. Alyscum salterns, D.

9. Amceba dijftuem, E. ; 9 a, expanded ; 9 6, contracted.

10. Amphileptus fasciola, E. 10 a, dorsal view ; 10 6, side view.

11. Amphimonas dispar, D.

12. Anisonema stdcata, D.

13. Anthophysa Mutteri, Bory, Duj. (Epistylis vegetans, E.) ; 13 «, entire organism ; b,

single body.
\ka.Arcella wdgaiis, E., dorsal view; 14 &, Arcella acideata, E., under view; 14 c, Arcella

dentata, E., under view.
\5a.Aspidiscus lynceus, E., under view ; 15 b, Asp. denticidata, E., side view.

16. Astasia hcematodes, E. a, contracted j b, c, (7, in different states of expansion.

17. Astasia limpida, D. (^L. pusilla, E.). «, expanded ; b, altered in shape.
l8a.Bodo ffrandis, E. ; 18 b} c, Bodo socialis, E.

19. Bursaria vernalis, E., under surface.

20. Carchesium polypinum, E.

21. Carchesium polypinum, E., separate body.

22. Cercomonas acuminata, D.

23. Cercomonas crassicauda, D.

24. Various forms of Trachelomonas, arranged by Ehrenberg in the genera Trachelomonas,

Chcetoglena, and Doxococcw. See TRACHELOMONAS.
25a.Chcetomono8 globulus, E. ; 25 6, Ch. constricta, E.

26. a, 6, Cheetotyphla armata, E. ; c, CA. aspei'a, E.

27. Chilodon cucidMuSj E. a, under view ; 6, side view.

28. Chilomonas granulosa, D.

29. Chlamidodon mnemosyne, E., ventral surface.

30. Chlamidomonas pulviscidus, E. (Diselmis viridis, D.), in various stages of development.

31. Chlorogonium enchlorum, E., (upper and lower figure) in different stages of development.

32. Colacium vesiculosum, left-hand figure j C. stentorium, right-hand figure.

33. Coleps hirtus, E. (a, after Ehr., 6, after Duj.).

34. Crumenida texta, D.

35a. Cryptoglena conica^ E. ; 35 b, Cr. pigra, E.

SGa.Cryptomonas ovata, E. ; 6, C. kntimdaris, E. ; c, C.fusca, E. ; d, C. globulus^ D. ; e,

C. incequalis, D.
37a.Cyclidiiim distortum, D. ; 6, C. abscissum, D. ; c and c?, C. glaucoma, E. : c, side view ;

d, dorsal view.

38. Cyphidium aureola, E. a, dorsal view ; in b the expansion is seen.

39. Dtfflugia proteiformis} E., a and b.

40. Dileptus folium, D.

41. Dmobiyon sertularia^ E.

42. Dinolryon petiolatum, D.

43. Diophrys marina, D. a, under view ; 6, side view.

44. Discocephalus rotatonus, E. «, dorsal view ; b, side view.

45. Disoma vacUlans, E.

46. «, Distigma proteus, E. ; 6, D. viride, E.

47. a, Doxococcus ruber, E. ; &, Z). pulvisculus, E.

48. Enchelys pupa, E.

49. Enchelys nodulosa, D.

50. Epipyxis utricidus, E.

51a. Epistylis anastatica ; 51 6, single body of j&. branchiophUa ; 51 c, less magnified.

52. Ervilia legumen, D. (&gyria kg., Cl. & L. ; Euplotes monostylus, E.). a, under view ;

b, side view.

53. Euglypha tuberculata, D.

54. Euglypha alveolata, D.

55. Amblyophis viridis, E.

INFUSORIA.

P1.3Q

' 3

PLATE 31. — Infusoria.

Figure

1. Euglena pyrum, E.

2. Euglena viridis, E. a, b, in different

states of contraction and extension.

3. Euglena longicauda, E. (Phacus longi-

cauda, D.), with the body twisted.
Fig. 63, the same, after Duj.; the
body flat.

4. Euglena acus, E., undergoing longitu-

dinal division.

5. Euplotes patetta, D. a, under view ;

b, lateral view.

6. Euplotes vannus, E., under view.

7. Gastrochcetafissa, I).

8. Glaucoma scintillans, E.

9. Peridinium cinctum, E.

10 a, b. Glenodinium cinctum, E. ; 10 c (be-
tween figs. 49 £ 50), Glenodinium
apiculatum, E.

11. Peridinium fuscum, E.

12. Peridinium tripos, E.

13. Peridinium fusus, E.

14. Glenomorum tingens, E.

15. GromiafluviatiliS) D., with its expan-

sions extended.

16. Trichodina pediculus, E. a, side view ;

b, under view.

17. Heteronema marina, D.

18. Himantophorus charon, E., under view.

19. Himantophorus charon, E., side view.

20. Hexamita nodulosa, D.

21. Holophrya brunnea, D.

22. Holophrya ovum, E.

23. Ichthydium podura, E.

24. Chcetonotus larus, E.

25. Colpoda cucidlus, E.

26. Kerona pustulata, D. (Stylonichia p.,

E.).

27. Kerona mytilus, D. (Stylonichia m.t E.),

under view.

28. Kerona mytilus, D. (Stylonichia m., E.),

side view.

29. Stylonichia histrio, E., under view.

30. Stylonichia lanceolata, E. a, under view ;

6, side view.

31. Kondylostoma patens, D., under view.

32. Kondylostoma patens, D., half side view.

33. TracMocerca viridis, E.

34. Amphileptus papillosus, E.

35. Lagenella euchlora, E.

36. Cryptomonas (Lagenella, E.) inftata, D.

37. Leticopkrys striata, D.

38. Leucophrys patula, E. a, dorsal, &, ven-

tral surface.

Figure

39. Loxodes rostrum, E. (Pekcida rostrum,

D.).

40. Loxodes dentatus, D.

41. Loxodes bursaria, E., under view.

42. Loxophyllum (Amphileptus, E.) melea-

gris, D. a, dorsal view ; 6, anterior
portion twisted.

43. a, Microglena punctifera, E. ; i, TfeT.

monadina, E.

44. «. Monas lens, D. ; 6, the same (?) with

two anterior cilia ; c, M. attenuata, D.

45. Nassula elegans, P], ; 6, teeth.

46. Nassula aurea, E.

47. Opalina (Bursaria, E.) ranarum, Purk.

and Val.

48. Ophrydium versatile, E., portion expan-

ded by compression.

49. Ophrydium versatile, E., marginal por-

tion, in the natural state.

50. Ophrydium versatile, E., isolated body.

51. Ophryoglena atra, E.

52. Oxytricha pellionetta, D.

53. Oxytricha gibba, F., side view.

54. Oxyrrhis marina, D.

55. Panophrys chrysalis, D.

56. Paramedum aurelia, E., dorsal view.

57. Paramedum aurelia, E., side view.

58. Pantotrichum lagenula, E.

59. Peranema olobulosa, D.

60. Phialina vermicularis, E.

61. Phialina viridis, E.

62. Phacus (Euglena, E.) pleuronectes, D.

63. Phacus (Euglena, E.) longicauda, I).

64. Plagiotoma lumbrici, D.

65. Planariola rubra, D.

66. Pleuronema chrysalis, D.

67. Pfeo^m v^re«, D.

68. Polyselmis viridis, D.

69. Polytoma uvella, E.

70. Prorocentrum micans, E.

71. Prorocentrum micans, E.; side view.

72. Prorodon teres, E.

73. Prorodon teres, E., teeth.

74. Scyphidia ruc/osa, E.

75. Spathidium hyalinum, D. (Leucophrys

spathula, E.).

76. Spathidium hyalinum, D., anterior part

twisted.

77. Spirostomum ambiguum, E.

78. Spirostomum ambiguum, E. ; posterior

end more magnified.

INFUSORIA

PI 3 L.

/

A^esbdel

London . John VsnVoors t

PLATE 32.— Infusoria.

Figure

1. Tegument of Paramecium aurelia, dried, showing the depressions at different

foci, &e. (!NTK. p. xxxvii.)

2. Paramecium aurelia. a, with globules of sarcode ; 2 b, free globule of sarcode,

with numerous vacuoles ; 2 c, the same, become reticular.

3. Stentor Mulleri^ E.

4. Tintinnus inquilinus, E.

5. Trachelius lamella, D., a and 6.

6. Trepomonas ay His, D.

7. Trichoda angulata, D.

8. Trichodiscus sol, E.

9. Trichomonas vaginalis, D.

10. Trichomonas limacis, D.

11. Trinema acinus, D.,= Euglypha pleurostoma, Cart.

12. Trochilia sigmoides, D., ventral view.

13. Trochilia sigmoides, D., dorsal view.

14. Urocentrum turbo, E.

15. Uroleptus piscis, E., a ; ft, Z7. lamella, E.

16. Uronema 'marina, D.

17. Urostyla grandis. E.

18. Uvella virescens, E., a and 6.

19. Vaginicola crystallina, E.

20. Cothurnia imberbis, E.

21. Vorticella nebidifera, E., «; 21 6, body separated by division; 21 c, body of

V. microstoma, showing the mouth, the nucleus (auct. ; testis, E.), and the
contractile vesicle (vesic. seminal., E.).

22. Zoothamnium arbuscula, E., a ; 22 b, separate body of Z. affine.

23. Zygoselmis nebnlosa, D. a, b, in different states of contraction.

24. Arcella vulgaris, E., half side view of young, with expansions extended.

25. Acineta-stage of Opercularia articulata, E. a, dendritic nucleus ; b, envelope ;

c, tentacles; d, vacuoles ; e, group of fat-granules ; /, enlarged stalk.

26. Vorticella microstoma, E., full-grown, a, oesophagus; b, peristome; c, con-

tractile vesicle ; d, nucleus ; e, gemma or bud ; /, mature bud.

27. Vorticella microstoma, E. (old), encysted upon its extended stalk, with its

nucleus, contractile vesicle, and retracted cilia.

28. Vorticella microstoma, E. (young), encysted upon its contracted stalk.

29. Vorticella microstoma, E., encysted and stalkless. a, cyst ; c, contractile vesicle ;

d, nucleus.

30. Isolated nucleus of an old Vorticella microstoma.

31. Actinophrys-st&ge of Vorticella microstoma. The cyst is partly separated from

its contents ; the nucleus and contractile vesicle are visible.

32. Two of the above in conjugation.

33. Two Podophrya-stages of Vorticella microstoma in conjugation.

34. Cyst of Vorticella microstoma discharging its brood of germs, a, gelatinous

substance, containing b the germs ; c, neck-like orifice of parent vesicle ;
d, cyst ; e, parent vesicle.

35. Spirochona gemmipara, Stein, a, peristome with its funnel-shaped process ;

b, nucleus ; c, gemma or bud.

36. Acineta-stage of the same, a, tentacles ; b, nucleus ; c, mature swarm-germ.

37. Paramecium chrysalis, E., undergoing longitudinal division.

38. Glaucoma scintillans, E., undergoing transverse division.

l\'l ! SORIA

PI.32.

Tu,TerW«st i«L

Johr. Van Voorst

PLATE 33.— Insects.

Figure

1. Head of Blatta orientalis, from before, a, antennae, cut off; b, epicranium ; c, eyes ;

d, clypeus ; e, labrum ; g, maxillae ; h, maxillary palpi j k, labial palpi.

2. Head of Blatta orientalis, under portion, a, stipes ; h, palp of maxilla ; », palpiger ;

k, palp ; I, mentum; * paraglossa of labiuni ; m, submentum and gula; x occiput.

3. Head of Hydrous piceus, under view, a, antennae; c, eye; e, labruin; /, mandible;

g, maxilla ; h, maxillary palp ; i, ligula ; k, labial palp ; I, mention ; m, submentum ;
n, gula ; X occiput.

4. Ocelli of Agrion fulvipes.

•5. Portions of cornea of eye of Acheta domestica. a, with hexagonal, 6, with quadran-
gular facets.

6. Perpendicular section of part of the eye. c, faceted cornea ; g, ganglionic expansion

of n, the optic nerve ; ?', bacilli arising from the ganglion, surrounded by choroid
pigment. 6*, cornea! lenses c, with bacilli r ; from eye of a beetle.

7. Antenna, setaceous (Achetidse, &c.).

8. Antenna, ensiform (Locustidse).

9. Antenna, filiform (Carabidae).

10. Antenna, moniliform (Tenebrionidae, £c.). a, scapus ; 6, pedicella ; c, clavola.

11. Antenna, serrated (Elateridae).

12. Antenna, imbricated (Prionidae).

13. Antenna, pectinated (Lampyridae).

14. Antenna, bipectinated (Bombycidae).

15. Antenna, flabellate (Elateridae).

16. Antenna, clavate (Coleoptera).

17. Antenna, capitate (Coleoptera).

18. Antenna, lamellate and perfoliate (Melolontha). a, scapus ; b, pedicella ; c, clavola ;

d, lamellae.

19. Antenna of Glolaria. a, scapus; 6, pedicella; c, clavola; d, capituluin.

20. Antenna, plumose (Muscidae).

21. Antenna, plumose (Culex pipiens, male).

22. Trophi of Blatta orientalis. a, labrum ; b 6, mandibles ; c, maxillae (f lacinia, * galea) ;

d, internal tongue ; e, labium.

23. Tongue of cricket (Acheta domestica'). a, b, c, parts of a fibre more magnified.

24. Head of mason-bee (Anthophora retusa), front view. «, antenna ; 6, ocelli ; c, eye ;

d, clypeus ; e, labrum ; /, mandible ; g, maxilla ; h, its palp ; «, palpiger or part of
the ligula; k, labial palp; * ligula, commonly called the tongue ; x, paraglossae.

25. Maxillae and labium of honey-bee (Apis mettificd). g, maxilla ; h, its palp ; k, labial

palp ; /, mentum ; * ligula, commonly called the tongue.

26. Trophi of water-scorpion (Nepa cinerea). * lingua ; /, mandibles ; g, maxilla ; *,

labium.

27. Trophi of bug (Cimex lectularius). a, mandibles united ; 6, maxillae ; the median

organ is the labium.

28. Antlia of red admiral butterfly ( Vanessa atalanta). a, separate papilla ; b, end of antlia

extended ; c, transverse section of antlia near its root; *f tracheae ; t tube ; «, entire
organ with two maxillae slightly separated at the end ; e, tooth ; /, section near the
end, showing the position of the papillae *, and the canal X .

29. Proboscis of the blow-fly (Musca vomitoria). a, maxillary palpi ; c, lobes of labium.

29 a, portion of margin more magnified.

30. Trophi of female gnat (Culexpipiens). a, antennae ; d, tongue ; e, labrum ; //, man-

dibles ; g g, maxillae ; f, labium.

31. Setae of the same, more magnified, d, tongue ; e, labrum ; /, mandible ; g, maxilla.

32. Trophi of flea (Pulex irritans). d, labrum ; /, mandibles or lancets ; g, maxilla ; h,

maxillary palpi ; k} sheaths corresponding to* labial palpi.

33. Trophi of flea, more magnified, d, labrum ;/, end of mandible ; k} sheath ; /, labium j

m, mentum.

INSECTS

PLATE 34.— Insects.

Figure

1. Gizzard of cricket (Acheta domestica).

2 a. Under membrane of elytrum of cockchafer (Melolontha vulgaris) ; 26, separate
hair or spiniform papilla (ELYTRA).

3. Scale of Lepisma saccharina, in liquid, showing air-bubbles imprisoned by the

longitudinal ridges.

4. Hind leg of neuter honey-bee (Apis mellifica), with pollen-brushes on the first

joint of tarsus, a ; c, tibia ; d, femur ; e, trochanter. 4 6, outside of tibia
hollowed out.

5. Leg of middle pair of Gyrinus natator. a, tarsus; c, tibia; d, femur; e, trochanter.

6. Anterior leg of male Dytiscus marginalis. a, tarsus, the first three joints with

the suckers ; b, one of the smaller ones more magnified ; c, tibia.

7. Leg of fly (Musca domestica). a, tarsus ; c, tibia ; d, femur ; e, trochanter.

7 6, ear of cricket.

8. Tarsal pulvillus of blow-fly, with hair-like suckers.

9. One of the hair-like suckers of the same, more magnified.

10. Anterior wing of male cricket (Acheta domestica). a, drum ; b, file (fig. 12, the

file more magnified).

11. Anterior wing of humble-bee (Bombus terrestris). n, fold over which the hooks

of the posterior wing play. (See INSECTS, wings, and WINGS.)

12. Pile of cricket (compare fig. 10, 6).

13. Costal nerve of hind wing of humble-bee (Bombus terrestris\ with the hooks

(See INSECTS, wings.)

14. Sting and poison-apparatus of mason bee (Anthophora retusa). a, b, sheath of

sting ; c, reservoir ; d, duct ; e, /, secretory organs.

15. Single sting of wasp ( Vespa vulgaris).

16. Spinning-organs of silkworm (Bombyx mori).

17. Trachea of a caterpillar; lower part of the branch containing air.

18. Internal reproductive organs of male mole-cricket (Gryllotalpa vulgaris). a,

testes ; 6, vasa deferentia ; c, c', prostate (blind tubes) ; d, root of penis, with
ca?ca (Cowper's glands) at the upper part.

19. Pemale organs of the same, a, a, ovaries; b, b, oviducts; c, receptacle of

semen (blind sac), the very slender tube of which, c', opens into the vagina d.

20. Battledore scale of Polyommatus argiolus, dry ; 20 a, a portion immersed in

water, and more magnified.

21. A scale of the same seen in Canada balsam.

22. Scale from the wing of the gnat (Culex pipiens).

23 a. Scale from the wing of male Pontia rapce, dry ; 23 b, portion of wing of the
same, showing the attachments of the two kinds of scales, a and b.

24. Scale from wing of male Pontia brassicce, dry.

25. Scale from underside of wing of clothes-moth (Tinea pellionella).

26. Portion of wing of Pontia brassicce, dry, showing the imbricated arrangement

of the scales, and the wrinkling of the epidermis at their insertions.

27. Hair-like scales from clothes-moth, dry.

28 a. Scale from wing of Lasiocampa quercus, dry ; 28 &, upper portion of the same,
more magnified, dry.

29. Scale from wing of Papilio Paris, dry.

30. Scale from larva of Attagenus pellio, dry.

31. Portion of the above, more magnified.

32. End of one of the posterior legs of the larva of a Sphinx.

33. Anterior leg of the same.

34. Spiracle of Dytiscus marginalis, with one of the marginal processes more mag-

nified.

35. Portion of outer membrane of the ovum of the blow-fly (Musca vomitoria).

loader. Jr

PLATE 35.— Insects.

Figure

1. Larva of gnat (Culev pipiens).

2. Organs of larva of Agrion puella. a, ocelli ; 6, oesophagus ; c, gizzard ; c?, sto-

mach ; e, Malpighian vessels truncated ; /, intestine and rectum ; g, caudal
branchiae ; 7t, tracheae.

3. Clothes-louse (Pediculus vestimenti).

4. Hcematopinus suis ; 4*, leg more magnified.

5. Philopterus (DocopTiorus) communis.

6. Trichodectes latus ; 6*, labium and labial palpi.

7. Liotheum (Menopon) pallidum.

8. Gyropus ovalis. J

9. Pulex felis (flea of cat), female, a, spiracles ; b, head ; c, thorax ; d, maxil-

lary palpi ; 0, setae ; /, epimera ; g, coxae ; h, trochanter ; {, femur ; ^, tibia ;
Z, tarsus ; X , pygidium ; 9 a, separate antenna.

10. Part of Pulex canis (dog's flea), a, prothoracic setae ; 5, cephalic setae.

11. Head of flea from common bat (PFLEX).

12. Antenna of flea from pigeon (PTILEX).

13. Posterior end of abdomen of pigeon's flea ; male (PULEX).

14. Head of larva of Dytiscus marginalis. a, eyes ; 6, antennae ; c, mandibles ;

d, maxillae ; e, maxillary papi ; /, labial palpi.

15. Pupa of Ephemera vulgata. a, abdominal branchiae.

16. Larva of Acilius sulcatus (formerly Dytiscus sulc.).

17. Pupa of Agrion puella (LiBELLULma;) ; 17*, caudal branchial plate.

18. Lepisma saccTiarina.

19. Larva of Gyrinus natator.

20. Rectum of ^Eschna grandis ; 20*, portion more magnified (LIBELLULID^E).

21. Pupa of Calepteryx virgo.

22. End of abdomen of Libellula ferruginea.

23. Sheep-tick (MelopTiila ovinus).

24. Flea of the mole (PULEX).

25. Head of Geophilus longicornis (one of the MTEIAPODA).

26. Head of a LithoUus (one of the MTBIAPODA).

27. Fibres of silk-worm's silk.

28. Three lobes of the fatty body of the larva (caterpillar) of Saturnia carpini.

29. End of abdomen of JEschna grandis.

30. Epidermis of cricket (Acheta domestica).

31. Fat-body of /c7m6ww<M-larva, developing from cells.

32. Egg of an aquatic insect (?) common in bog-water.

INSECTS

1*135.

London Joh .

RMCoUing

PLATE 36.— Insects, etc.

Figure

1. Lachnus, head of, from below

2. Aphis, head of, from above (

3. Aphis brassicce (

4. Tetraneura ulmi

5. Pemphigus bursarius

6. Trama radicis ( APHID js).

7. Forda formicaria (

8. Chalcidite, head of

9. Chalcidite : «, under surface of abdomen of female (CHALCIDIDJE) ; 6, separate

ovipositor.

10. Etdophus nemati, larva of

11. Eulophus nemati, pupa o

12. Encyrtus atricollis (CH

13. Eulophus pectinicornis

14. Callimome cynipis

15. Cynips, section of abdomen of female

16. Rhodites rosce

17. Cynips folii (CYNIPI

18. Teras terminalis

19. Neuropterus longipennis

20. Ibalia cultellata

21. Notamia bursaria.

22. Actinodiscus Barbadensis.

23. Distoma rubrum : a, portion of common mass ; 6, individual body.

24. Eucratea (Scruparia) chelata.

25. Salpingia Hassallii.

26. Gemellaria loricata.

27. Limnoria terebrans.

28. Monactinus duodenarius,

29. Spirorbis nautiloides : a on seaweed ; 6, magnified.

T West,.

London, JoknTan Voorst,

RM. Colling

PLATE 37.— Lichens.

Figure

1. Fragment of the thallus of Parmelia (PTiyscia) parietina, Ach., with young

apothecia, and spermogonia, s, near the edges of the lobes.

2. Yertical section of one of the spermogonia and the part of the thallus in which

it lies. This section shows the upper and lower cortical layers of the thallus,
with the intermediate filamentous medulla and its globular gonidia.

3. Fragment from the wall of the above spermogonium, more magnified to show

the articulated filaments (spermatopliores) which bear the spermatia.

4. Spores of the same, treated with iodine ; the dark portion represents the proto-

plasmic contents.

5. A spore which has germinated.

6. Fragment of a vertical section through the apothecium of Parmelia (Physcia)

stellaris, Fr. The upper part is the fertile layer, or thalamium, b, composed
of ihecce with spores, and paraphyses ; this rests on the hypoihecium, h, beneath
which is a portion of the medullary layer, with gonidia, g.

7. Ripe spores of the same.

8. Ripe spores, germinated and not germinated, treated with sulphuric acid, and

broken, showing the clear endospore inside the hard eocospore.

9. Ripe spore of Verrucaria nitida, Fr.

10. Isolated spermatia from the spermogonia of ditto.

11. Ripe spores of Peltigera horizontalis, Hoffm.

12. Fragment of the ihalamium of Sphcerophoron coralloides, Pers., with thecce in

different stages of development, and free ripe spores.

13. Yertical section of a spermogonium of Collema melcenum (Jacobecefolium), with

spermatia escaping. Imbedded in the thallus are the moniliform gonidial
filaments.

14. Isolated articulated filaments from the same.

15. Isolated spermatia from these filaments.

16. Yertical section of a spermogonium of Cladonia rangiferina, Hoffm., with sper-

matia escaping from its orifice.

17. Ripe spores of Urceolaria scruposa, Ach., seen in water.

18. Fully developed spores of Umbilicaria pustulata, Hoffm.

19. Ripe spores of Lecanora parella, Ach.

LICHENS

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PLATE 38.— Morbid products, human.

Figure

1. Aphtha, a, spores of fungus (Oidium dlbicans); 6, fibres; c and/, Bacterium

termo ; d, e, epithelial scales ; #, early state of Bacterium.

2. Areolar tissue, with formative cells and homogeneous basis ; from a fibroid

tumour of the upper jaw.

3. Cells of fatty tissue in degeneration, a, fat ; 6, nucleus ; c, cell with thickened

walls.

4. Corpuscles of pus.

5. Corpuscles of pus, treated with acetic acid, a, nuclei with object-glass slightly

raised ; 6, the same when this is depressed.

6. Pyoid corpuscles, of Lebert.

7. Granule-cells and loose fat-globules, some of the former with distinct cell-wall

and nucleus ; in the lowest these are absent : from a cutaneous cancer.

8. Tubercle in lung, showing pulmonary fibres, tubercle-corpuscles, and fat-granules.

9. Tubercle-corpuscles, more magnified, a, seen in water ; 6, treated with acetic

acid.

10. Fibroplastic cells from a sarcomatous tumour of the thigh, a, loose secondary

cells ; 6, fusiform cells ; c, parent cells ; d, cell forming fibres.

11. Cancerous tissue from a medullary cancer, containing but few and pale fibres.

a, free nucleus ; 6, nucleus within a cell.

12. Cancerous tissue from a scirrhous cancer ; the fibres numerous, but delicate

and not arranged in bundles.

13. Capillary vessel in a state of fatty degeneration, showing the oblong nuclei, and

the minute fat-globules in the substance of the wall of the vessel.

14. a, fatty degeneration of the muscular bundles of the heart ; the transverse striae

are absent, and globules of fat are disseminated through the substance. 6,
from muscle of the thigh, showing collapse of sarcolemma and partial absorp-
tion of muscular substance, with globules of fat in the remainder.

15. Intercellular fatty degeneration of encysted cutaneous tumour (cholesteatoma).

16. Tissue of medullary cancer of ovary, a, granule-cells ; 6, cancer-cells ; the fibres

are very few and slender.

17. Tissue of cancer of the oesophagus, a, cancer-cells ; b. their nuclei (secondary

cells) ; c, nucleoli (tertiary cells) ; <Z, cancer-cells with highly developed
nuclei ; e, granule-cells ; /, fibres and fusiform cells.

18. Colloid or alveolar cancer of the peritoneum, a, nuclei or secondary cells, the

walls of the two parent cells are seen at b ; c, nuclei of areolar tissue ; the
contents of the cells are of gelatinous consistence.

19. Portion of an enchondroma, showing cells imbedded in a homogeneous basis.

a, cell with nucleus (secondary cell) and nucleolus (tertiary cell) ; c, secondary
cell with processes ; 6, secondary cell from which the primary has disappeared.

20. 1

L Cancer-cells from medullary cancer.

21. J

22. Colloid corpuscles, a, simple ; &, c, concentric or laminated corpuscles from

hypertrophied heart ; d,f, laminated corpuscles from the prostate, containing
calcareous matter; e, concentric corpuscle from a cyst in an atrophied kidney.

Moi; r, i it PRODUCTS.

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PLATE 39. — Opaque and Polarizing Objects.

Figure

1. Two rhombs of selenite as seen under different relative positions of the polarizer

and analyzer.

2. Crystals of acetate of copper (ACETIC ACID, DICKROISM).

3. Crystals of uric acid under polarized light, natural and artificial (compare PI. 12).

4. Prisms of ammonio-phosphate of magnesia, under polarized light.

5. Ellipsoidal-constricted, or dumb-bell crystals of oxalate of lime, under polarized

light.

6. Crystals of oxalate of soda, under polarized light.

7. Crystals of oxalate of ammonia, under polarized light.

8. Crystals of oxalate of chromium and ammonia, under polarized light.

9. Crystals of salicine, under polarized light.

10. Crystals of sulphate of cadmium, under polarized light.

11. Crystals of oxalurate of ammonia, under polarized light.

12. Crystals of oxalurate of ammonia, under polarized light with a plate of selenite.

13. Elytrum of Gurculio imperialis, as an opaque object.

14. Seed of white poppy (Papaver somniferum), opaque object.

15. Seed of sweet-william (Dianthus barbatus), opaque object.

~\ A 1

i y* !• Seeds of Silene gallica, opaque objects.

18. Seeds of foxglove {Digitalis purpurea), opaque objects.

19. Egg of puss-moth (Cerura vinula), opaque object.

20. Eggs of bug (Cimex lectularius*), opaque objects ; the lids are removed.

21. Eggs of Pontia rapce, opaque objects.

22. Skin and scales of sole (Solea vulgaris), opaque objects.

23. Rhopalocanium ornatum.

24. Stephanastrum rhombus.

25. Eucertydium ampulla, front view.

26. Eucertydium ampulla, under view.

27. Podocyrtis Schomburglcii. ^PoLYCYSinsrA. Opaque objects.

28. Antliocyrtis mespilus.

29. Astromma Aristotelis.

30. Lychnocanium lucerna.

31. Haliomma Humboldtii.

32. Eggs of Pontia brassicce, opaque objects.

33. Portion of liver of cat ; the porta injected with red, the vena cava with yellow ;

opaque object.

34. Portion of lung of toad ; opaque object.

35. Kidney of pig ; arteries and Malpighian bodies red, urinary tubules white ;

opaque object.

36. Spiracle of Bombyx, opaque object.

37 ]

oo* [• Sections of Rhinoceros-horn, by polarized light.

39. White hairs of horse, interlaced ; by polarized light.

40. Tous-les-mois starch, by polarized light with plate of selenite.

( HIXQIT. & P01 .ARIXIXC

PI .

Condon John V«ui Voorst

PLATE 40.— Pollen, etc.

Figure

1. a and b, spiral tissue of lining of anther from wallflower (CTieiranthus cheiri).

2. Ditto, from London Pride (Saxifraga umbrosa).

3. Ditto, from Lupinus nanus.

4. Ditto, from a cactus (Cereus speciosus). a, side view ; 6, from above.

5. Ditto, from daisy (Bellis perennis).

6. Pollen of Viola odorata. a, side view ; 6, end view ; c, in water.

7. Pollen of Apocynum venetum.

8. Pollen of daisy (Bellis perennis).

9. Pollen of Mesembryanfhemum.

10. Pollen of Alisma plantayo.

11. Pollen of Lupinus nanus.

12. Pollen of garden-geranium (Pelargonium speciosum). a, front view ; 6, side

view.

13. Pollen of passion-flower (Passiflora ccerulea). a, perfect grain ; 5, grain with

the lid of a pore opening.

14. Pollen of Epilobium montanum.

15. Pollen of Periploca grceca.

16. Pollen of Pinus sylvestris.

17. Pollen of Erica multiflora.

18. Pollen of Sherardia arvensis. a, side view ; 6, end view ; c, ditto in water.

19. Pollen of Basella alba.

20. Pollen of Passiflora aquilegicefolia. a, side view ; 6, end view ; c, ditto in water.

21. Pollen of Impatiens noli-me-tangere.

22. Pollen of Cucurbita pepo^ in water.

23. Pollen of Ruellia formosa.

24. Pollen of Thunbergia alata, a ; of Mimulus moschatus, the musk-plant, b.

25. Compound pollen of Acacia laxa.

26. Pollen of Hibiscus trionum.

27. Pollen of chicory (Cichorium Intybus).

28. Pollen of Sonchus palustris, side and end views.

29. Pollen of Statice linifolia, end and side views.

30. Pollen-grain with tube upon the stigmatic papillae, from Laihrcea squamaria.

31. Spermatozoid from the globule of Char a fragilis.

32. Spermatozoids from the antheridium of Marchantia polymorpha.

33. Spermatozoids from the antheridium of Polytrichum commune.

34. Spermatozoids from the antheridium of a Fern ( Gymnogramma}.

35. Spiral-fibrous cells of the sporange of Marchantia polymorpha.

36. Elater of Marchantia polymorpha.

37. Fragments of ditto, a, from the middle ; 6, one end.

38. Elater of Frullania dilatata.

39. Elaters (a) and spores (b) of Trichia.

40. Fragment of the same elater showing the three internal spiral fibres.

I1! 40

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PLATE 41.— Polypi and Polyzoa.

Figure

1. Areolar tissue of sea-anemone (Actinia mesembryanihemum)', with spicula, cells,

and fibre-cells.

2. Spicula from the same.

3. Alcyonella stagnorum. a, entire polyzoary ; b, perpendicular section, showing

tubes and ova ; c, back view of polype with tentacles ; d, ova.

4. Campanularia volubilis. a, growing upon a piece of Plumularia falcata ;

6, portion of polypidom more magnified ; 4 c, cell of Laomedea dichotoma
with ova ; eZ, medusa-germ or gonozoid of Clytia.

5. Canda (Cellularia) reptans, portion of polypidom of. 5 a, Bicellaria (Cellu-

laria) ciliata ; 5 6, the same more magnified, * a bird's-head process ; 5 c, pos-
terior view of a cell of Canda rtptans, with its appendices ; 5 d, three appen-
dices to a cell of the same ; 5 e, polype expanded; 5/, perforated septum.

6. Corallium rubrum ; axis with polypiferous crust.

7. Spicula from the crust.

8. a, transverse section of the axis of red coral, from the furrowed exterior towards

the centre ; b, longitudinal section.

9. Body of Cristatella mucedo.

10. Ova of the same, seen from above.

11. Branch of Sertularia rugosa.

12. Portion of the same, magnified, with cells a, and vesicles b.

13. Sertularia pumila.

14. Portion of the same, magnified, a, cell; b} vesicle.

15. Sertularia operculata.

16. Portion of the same, magnified, a, cells ; 6, vesicles.

17. Lepralia variolosa.

18. Membranipora pilosa. 18*, polypes protruding from the cells ; 18 a, cell ;

5, valve through which the ciliated tentacles c protrude ; e?, oesophagus ; e,
pouch containing the stomach, liver, &c. ; /, place of gyration of particles in
intestine ; g, rectum.

19. Piece of Flustra carbasea.

20. Cells of the same, magnified.

21. Hydra viridis, attached to Lemna.

22. Stinging organs of Hydra vulgaris. a, capsule with the spines and filament

enclosed ; 6, capsule with the spines and filament protruded ; c, very minute
capsules ; c?, capsule imbedded in a globule of the sarcodic substance of the
body.

23. Tentacle of Hydra viridis. a, stinging organs in situ.

24. Hydra viridis, with spermatic capsules a, and ovarian capsule b.

25. Ovum of Hydra, with the young polype bursting through its shell.

26. Bird's-head processes of Flustra avicularis.

27. Spiculum of a Gorgonia.

28. Spicula of Alcyonium digitatum.

29. Globules of sarcodic substance of a crushed Hydra viridis. a, one containing a

small vacuole and several green granules ; the latter are more magnified below ;
b, a globule greatly distended by the formation of a large vacuole.

30. Tubulipora, with a polype protruding from a cell.

POLYPI & POLYZOA. ( BRYOZOA .

PI 41

Tuf fen West .Dd

I.oadon.JbhnVan Voorst

R M Col!m|

PLATE 42.— Rocks.

Figure

1. Fluid-lacunas in quartz, magnified 120 diameters.

2. Glass-lacunas in triclinic felspar. Lava of A.D. 1607 ; near Raudazzo, Etna '•>

77 diams. Crossed Nicols.

3. Trichites in obsidian. Yellowstone district, U. S., 250 diams.

4. Crystallites in obsidian. Mexico, 30 diams.

5. Microliths (belonites) of augite, in pitchstone. Corriegills, Arran, 55 diams.

6. Spherules in obsidian. Lipari, 25 diams.

7. Perlite. Buschbad, near Meissen, Saxony, 18 diams.

8. Fluxion structure around sanidine crystals in obsidian. Lower Geyser basin,

Yellowstone district, Colorado, U. S., 18 diams.

9. Granite. Cornwall, 25 diams. Polarized light. (Orthoclase, plagioclastic fel-

spar, quartz, and biolite.)

10. Syenite. Hemsbach, Germany, 30 diams. Polarizer only. (Hornblende, ortho-

clase, quartz, and magnetite.)

11. Minette (mica trap). Seifersdorf, Saxony, 55 diams.

12. Felstone (halleflinta). Schiesshyttan, Sweden, 120 diams. Grossed Nicols.

13. Trachyte. Drachenfels, Rhine, 55 diams. Polarized light. (Sanidine, oligoclase

sphene, <fec.)

14. Phonolite. Hohgau, Germany, 33 diams. (Nosean and hornblende.)

15. Diorite. Ontario, 55 diams. Polarized light. (Hornblende, triclinic felspar,

apatite, &c.)

16. Basalt. Wohlbach, near Adorf, Saxony, 18 diams. Polarized light. (Porphy-

ritic olivine crystals and magnetite.)

17. Basalt. Giant's Causeway, Ireland, 77 diams. Polarized light. (Olivine, tri-

clinic felspar, magnetite.)

18. Basalt. Titterstone, Clee Hill, Shropshire, 77 diams. Polarized light. (Augite,

triclinic felspar, apatite, &c.)

19. Phonolite. Wolf Rock, Cornish coast, 33 diams. (Nepheline and hornblende.)

20. Mica schist. Braunsdorf, Saxony, 18 diams. (Biolite and quartz.)

21. Millstone grit (coarse felspathic sandstone). Black Rocks, Cromford, Derby-

shire, 18 diams. Polarized light. (Fragments of quartz and felspar, with
ferruginous cement.)

22. Slate (Cambrian). Penrhyn Quarries, North Wales, 250 diams. Grossed

Nicols.

23. Great Oolite. Grimsthorpe Park, Lincolnshire, 18 diams.

24. Carrara marble, 33 diams. Polarized light.

The minerals mentioned, in brackets, form prominent objects in the drawings ;
but do not necessarily include all the constituents of the different rocks.

i\ S

a LI Voorst

PLATE 43.— Rotatoria.

Figure

1. Actinurus Neptunius, E., swimming, a, orifice of intestine.

2. Gizzard, with teeth of the same.

3. Head of the same, while crawling.

4. Albertia vermiculus, D. ; 4 a, teeth.

5. Anurcea curvicornis, E., dorsal view.

6. Anurcea curvicornis, E., half side view.

7. Asplanchna priodonta ; b, jaws and teeth.

8. Bracliionus amphiceros.

9. Brachionus rubens, jaws of.

10. CalUdina elegans.

11. CalUdina elegans, jaws.

12. Colurus deflexus, dorsal view.

13. Colurus deflexus, under view.

14. Colurus deflexus, teeth.

15. Conochilus volvox, isolated animal.

16. Conochilus volvooc, spherical group.

17. Conochilus volvox, jaws of.

18. Cycloglena lupus, a, tremulous bodies; b, contractile sac.

19. CypJionautes compressus, side view, a, pharynx ; b, nervous ganglion ; d, intestine.

20. Cyphonautes compressus, end view.

21. Diglena lacustris.

22. Diglena lacustris, jaws.

23. Dinocharis tetractis.

24. Dinocharis pocillum, teeth of.

25. Distemma forficula.

26. Distemma forficula, jaws of '.

27. Enter oplea liydatina.

28. Eosphora digitata.

29. Eosphora digitata, jaws of.

30. Euchlanis triquetra.

31. Euchlanis triquetra, jaws of.

32. Floscularia ornata.

33. Floscularia proboscidea, jaws of.

34. Furcularia Reinliardtii.

35. Furcularia Reinhardtii, jaws of.

36. Glenophora trochus.

37. Hydatina senta.

38. Hydatina senta, jaws of.

39. Hydrias cornigera.

40. Lindia torulosa.

41. Lindia torulosa, teeth of.

42. Plagiognatha Jiyptopus, D. (Notommata hyp., E.).

43. Lepadella, emarginata.

44. Lepadella ovalis, jaws of.

45. Limnias ceratophylli.

46. Mastigocerca carinata.

ROTATORIA

n.43

••

PLATE 44.— -Rotate ria.

Figure

1 . Megalotrocha flavicans.

2. Megalotrocha flavicans, jaws.

3. Melicerta ringens.

4. Melicerta ringens, removed from its sheath, a, rotatory lobes ; b, lips ; c,

accessory ciliated lobe ; d, tentacular processes ; c, pharynx or oesophagus
and jaws ; /, g, upper and lower stomach ; h, anus ; Jc, ovary ; Z, oviduct ;
m, spermatic organ ? ; n, tail ; o, disk ; p, sarcodic globules ; q, ovum.

5. Melicerta ringens, tentacular process of. a, setae ; b, conical body ; c, muscle.

6. Melicerta ringens, jaws of.

7. Metopidia triptera. a, contractile sac.

8. Microcodon clavus.

9. Monocerca rattus. a9 contractile sac ; 6, muscle.

10. Monolabis gracilis.

11. Monostyla quadridentata.

12. Monura dulcis.

13. Noteus quadricornis.

14. Notommata centrum.

15. Notommata centrum, jaws of.

16. (Ecistes crystallinus.

17. Philodina eryihrophihalma.

18. Pleurotrocha gibba.

19. Polyarthra platyptera.

20. Pterodina patina.

21. Ptygura melicerta.

22. Rattulus lunaris.

23. Rotifer vulgaris. a, contractile sac.

24. Salpina redunca, dorsal view.

25. Stephanoceros Eichhornii. a, tremulous bodies.

26. Synchceta baltica.

27. Scaridium longicaudum.

28. Stephanops cirratus.

29. Squamella oblonga.

30. Triarthra longiseta.

31. TriopTifhalmus dorsalis.

32. Theorus vernalis.

33. Typfilina viridis.

ROTATORIA

P.I.4-4.

Jchti Van\borit

PLATE 45.— Shell, etc.

Figure

1. Calcareous corpuscles of common starfish (Asterias ( Uraster) rub&ns), a, b, c, d,e;
/, the same from an Ophiura ; g, calcareous disk from an Echinus ; h, i, k, I, m, from
'an Ophiura (ECHINODEBMATA).
2*. Spine of an Ophiura ; 2, portion of the same more magnified.

3. A pedicellaria of the common starfish (Asterias rubens) ; on the right hand is a
portion of the margin more magnified to show the teeth.

4. Shell of Pinna, section parallel to the surface.

5. Shell of Pinna, section perpendicular to the surface.

6. Spine of an Echinus, transverse section. 6 a, segment of the same, more magnified.

7. Section of shell of a Terebratula ; a perpendicular to, b parallel with, the surface.

8. Portion of a sponge, with the spicula projecting from its surface.

9. Shell of oyster, a, b, sections parallel to surface.

10. Shell of oyster, showing the rhomboidal crystals of carbonate of lime.

11. Shell of oyster, showing the cellular appearance ; a, parallel with, b, perpendicular to,
the surface.

12. Shell of hen's egg, from a "soft " egg.

13. Shell of hen's egg, perfectly formed.

14. Shell of egg of ostrich, section parallel to surface.

15. Shell of egg of ostrich, section perpendicular to surface.

16. Shell of lobster, section perpendicular to surface.

19. Anchor-shaped spicular nooks of Synapta (ECHINODERMATA).
The remaining figures represent the spicula of sponges.

a. Elongate-fusiform, tubercular.

b. Acicular, acute at both ends.

b*. Subulato-acicular, base trifid, rays shortly bifid.

c. Subulato-acicular.

d. Subulato-acicular, base swollen.

e. Arcuato-acicular, acute at both ends.
/. Shortly cylindrical, ends doubly trifid.
</. Subulato-acicular, base turbinate.

h. Subulato-acicular, base capitate.

». Subulato-fusiform.

k. Elongato-subulate, base capitate.

/. Terete, geniculate.

m. Filiform, ends capitate.

n. Acicular, ends bifurcate.

o. Acicular, ends trifurcate.

p. Subulato-acicular, base triradiate.

q. Acicular, base tri-retrocuspid.

r. Uncinato-filiform.

s. Bacilliform, ends tri-retrocuspid.

t. Arcuate, ends uncinate.

w. Stellato-triradiate.

v. Geminate, arms subulate-filiform, geniculate.

w. Stellato-quadriradiate.

x. Stellato-quinqueradiate.

y. Stellato-rnultiradiate, ends capitate.

a. Subulate tuberculate.

/3. Arcuate spinulose, ends clavate.

y. Stellate insequiradiate.

d. Bacilliform spinulose, with dentate, discoid, rotate ends.

c. Globular, with subulate spines.

£. Oblong, with irregularly stellate ends, the rays capitate ;

77. Bacillifonn, with stellate rotate ends.

SI1KI.L &c.

PJ.45.

l-M.don.John g

PLATE 46.— Starch.

Figure

1. Section of a cell of the albumen of a young maize-seed, showing the nascent

starch-grains imbedded in protoplasm.

2. Starch-grains of rye, with a stellate hilum.

3. Section of a cell from the outer horny part of the albumen of maize ; the starch-

grains completely fill the cell, and by their crowded condition have compressed
each other into polygonal forms ; the hilum is visible.

4. Starch-grains of bean.

5. Free starch-grains of maize from the cells of the centre of the seed ; 5*, young

starch-grains of ditto.

6. Starch-grains of orris-root ; used to adulterate snuiF.

7. Compound starch-grains and separated granules, from the corm of the crocus.

8. Lenticular starch-grains of wheat, a, seen in face ; 6, seen edgewise.

9. Discoid starch-grains of barley. ««, front view ; &, edgewise.

10. Compound starch-grains and separated granules of oats.

11. Compound grains and separated granules of Portland arrowroot (Arum

maculatum).

12. Part of a section of a cell of the grain of rice, exhibiting very minute starch-

grains, firmly compacted as in maize.

13. A portion of the same, more magnified.

14. Starch-grains of Cassava (Jatropha Manihot)*. Tapioca.

15. Young starch-grains from the cells o*f the prothallium of a fern (Gymnogramma).

16. Compound starch-grains and separated granules of the bread-fruit (Artocarpus

incisa)*.

17. Starch-grains of Cycas circinalis*.

18. Starch-grains of arrowroot from Singapore*.

19. Starch-grains of an East-Indian arrowroot obtained from a species of Curcuma*.

20. Cell of a potato, showing the loosely -packed starch-grains.

21. Isolated starch-grains of the potato.

22. Starch-grains of Tacca pinnatifida, from Tahiti*.

23. Starch-grains of sago (from a Sagus ?)*.

24. Starch from plantain-meal (Musa). a, front view ; &, edgewise*.

25. Starch of Tous-les-mois (Canna). a, front view ; 6, edgewise*.

26. Starch-grains of true West-Indian arrowroot (Maranta arundinacea).

27. Isolated starch-grains from the cotyledon of a haricot bean.

28. Part of a cell of the stem of the white lily (Lilium candidum), showing nascent

starch-grains : a, forming in cavities of the protoplasm, c ; 6, nucleus.

* The figures to which the asterisk is appended were taken from specimens witli which we were
favoured from the Muieurn of Economic Botany at Kew.

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PLATE 47.— Vegetable Tissues.

Figure

1. Embryo-sac, and supporting cells, of Orchis rnorio.

2. The same, more advanced.

3. The same, with a germinal vesicle at its apex.

4. The same, with three germinal vesicles, just before impregnation.

5. The same, after the pollen-tube ( p t} has reached it, one of the germinal vesicles

(e) already being developed to form the embryo.

6. The same, more advanced, showing the first cell of the suspensor ($) at the

upper end.

7. Embryo-sac of Lathrcea squamaria before the origin of the germinal vesicles ;

p, amorphous protoplasm ; e, protoplasm in course of development into endo-
sperm-colls.

8. 9. Apices of very young hairs of the filaments of Tradescantia virginica ; n, n,

nuclei, containing nucleoli ; p, protoplasm.

10. Cylindrical cell from which are formed the parent cells of the spores of Mar-

chantia polymorplia ; p, primordial utricles of the parent cells.

11. The same, converted into a string of cells.

12. One of the parent cells isolated, with four primordial utricles of the spores.

13. The four spores free.

14. Transverse section of pith and internal wood of elder ; d, porous duct.

15. Epidermis of the leaf of the pine-apple, seen from above.

16. Vertical section of cork.

17. Transverse section of ditto.

18. Transverse section of stellate parenchyma of rush-pith.

19. Cellular tissue (parenchymatous) of the leaf of Orihotrichum pulchettum .

20. Cellular tissue (prosenchymatous) of the leaf of Hypnutn decipiens.

21. Section of the albumen of the seed of Areca Catecliu.

22. The same, after treatment with sulphuric acid and iodine.

23. Section of the bony albumen of vegetable ivory, a, cells and pits filled with

air ; 6, cells filled with Canada balsam.

24. Cell-membrane of Hydrodictyon utriculatum. I, the laminae of the cellulose

coat ; p, protoplasm.

25. Vertical section of the epidermis of a mistletoe-branch several years old.

26. The same, after boiling in solution of potash and treatment with iodine.

27. Transverse section of a liber-cell of the oak, after long boiling in nitric acid and

treatment with iodine.

28. Vertical section of the upper face of the leaf of Cycas revoluta. a, cuticle,

extending over the epidermal cells, which, like the deeper-seated cells, have
pitted secondary deposits.

H.47.

PLATE 48. — Vegetable Tissues.

Figure

1. Wood of Pinus sylvestris. a, radial vertical section ; b, tangential section of

the walls of two contiguous pitted wood-cells.

2. Tangential section of the wood of Casuarina equiseti folia, a, pitted wood-cells ;

6, duct ; c, cells of a true medullary ray ; d, cells of one of the concentric
medullary layers.

3. Vertical section of wood-cells of box.

4. Vertical (radial) section of wood-cells of the yew.

5. Vertical (radial) section of wood-cells of Araucaria imbricata.

6. Spiral-fibrous cells from the roots of Dendrobium alatum.

7. Wood-cells of Mammillaria, with broad spiral bands.

8. Spiral and annular vessels of rhubarb.

9. Reticulated duct from the same.

10. Scalariform duct of a tree fern.

11. End of a spiral vessel of the white lily.

12. Fragment of a larger and looser one.

13. Pitted duct of the lime (Tilia parvifolia).'

14. Wall of a pitted duct of Gassyta ylabella.

15. Walls of pitted ducts of Bombax pentandrum. a, next another duct ; 6, next

cells.

16. Wall of a pitted duct of Laurus Sassafras.

17. Wall of a pitted duct of Chilianthus arboreus.

18. Walls of pitted ducts of clematis (Clematis Vitalba).

19. End of a spiral-fibrous duct of Daphne Mezereon.

20. Walls of pitted wood-cells of Cycas.

21. Fragment of the wall of a large pitted duct of Eryngium maritimum.

22. Vertical section through a stoma of Aloe feroos ; the darkly shaded part repre-

sents the cuticular layer.

23. Fragment of a latex-duct of Euphorbia antiquorum, the latex containing starch-

grains of peculiar shape.

24. Epidermis of the petal of the daffodil, from above.

25. Fragment of the leaf of Sphagnum cymbiforme. a, empty cells with spiral

fibre ; 6, interstitial colls with chlorophyll.

26. Vertical section of the upper face of the leaf of Parietaria officinalis, with a

cystolith ; magnified 100 diameters.

27. A similar section from the leaf of Ficus elastica • magnified 100 diameters.

28. a and 6, sections of the cellular tissue of an onion-bulb, containing raphides.

29. Stomata and epidermis of Equisetum ; the siliceous coat remaining after the

destruction of the organic matter.

30. End of a liber-fibre of the periwinkle ( Vinca major), with fine spiral stria?.

31. Branched liber-cell of the radicle of Rhizophora Mangle.

32. Siliceous cast of the inside of a duct of unknown fossil wood ; the peculiar

concentric concretions of the silica imitate to a certain extent the so-called
glandular markings of Coniferse.

VEGETABLE TISSUES.

PI .48

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PLATE 49.— Various Objects.

Figure

1. Mixtures of oil and water (!NTK. p. xxxvii). a, water in oil ; b, c, oil in water.

2. Oceania cruciata (ACALEPH.-S;), epidermis of.

3. Oceania cruciata. a, b, stinging-capsules with filament included ; c, with fila-

ment expelled.

4. Diphyes Kochii (ACALEPH.E) ; organs of adhesion upon tentacles.

5. Oceania cruciata, portion of margin of disk, slightly magnified. a, ovary;

b, muscular bundles ; c, transverse vessel coming from the stomach ; d, mar-
ginal vessel ; e, /, tentacular filaments ; g, auditory organs. 5*, spermatozoa.

6. Infusorial embryos of ACALEPH.ZE.

7. 8, 9, 10. The same, further developed.

11. Strobile-segments; a, magnified ; 6, natural size.

12. Epidermis of Triton cristatus (water-newt).

13. Ciliated epithelium from frog's throat.

14. Alderia apiculosa.

15. Alderia pyriformis.

16. Hcemocharis, epidermis of. "^

17. Hcemocharis, transverse section of muscular fibres.

18. Hcemocharis, muscular fibre, showing the sarcolemma. LANNULATA

19. Hcemocharis, margin of cephalic disk, with branching mus- [

cular fibres c ; and, a, b, d, glands and ducts.

20. Aphrodita aculeata, hair of, treated with potash. J

21. Blood-corpuscles, human, a, d, surface view at different foci ; c, side or edge

view ; b, colourless or lymph-corpuscle ; e, coloured corpuscles altered, either
spontaneously or by mixture with foreign matters, as urine, &c. ; /, corpuscle
changed by tannic acid.

22. Blood-corpuscles of the goat (Capra hircus).

23. „ „ whale (Balcena).

24. „ „ ostrich (Strufhio}.

25. „ „ pigeon (Columba).

26. „ „ stickleback (Gfasterosteus aculeatus).

27. „ „ loach ( Colitis fossilis) ; 6, colourless corpuscle.

28. „ „ frog (Rana temporaria) ; 6, colourless corpuscle ; c, d,

the same altered by water.

29. „ „ triton (Triton cristatus) ; 6, colourless corpuscle ; c, c?,

e, /, altered coloured corpuscles.

30. „ „ Siren', 6, colourless corpuscle.

31. „ „ crab (Carcinus).

32. „ „ spider (Tegenaria domestica^).

33. „ „ cockroach (Blatta orientalis).

34. 99 „ worm (Lumbricusterrestris). a, corpuscle partly drawn

out, as occurs with the bodies of some Infusoria.

35. „ »'•'•• garden-snail (Helix asjpersa).

36. „ „ human, coloured, undergoing division.

37. Blood, human, in coagulation ; b, colourless corpuscle.

38. Cartilage of the ear of a mouse ; the fat is partly removed from the cells.

39. Cartilage of human rib.

40. Cartilage of human epiglottis.

41. Connective tissue, human, with fat-cells.

42. Formation of connective tissue from cells.

VAKIOFS (W.IK(TS.

. •

PLATE 50. —Various Objects.

Figure

1. Chlorogonium euchlorum, E., undergoing oblique division.

2, Elements of the chyle, a, molecules ; b, free nuclei ; c, chyle-corpuscles ; d} one of

the same with processes.

8. Coccudina costata, D.

4, Anystis ruricola.

6. Bacilli and cones of the retina of animals, a, /3, from the pigeon, a, bacillus ; a, pro-
per bacillus; b, its pale inner extremity; c, line of demarcation at the boundary of
the bacillar layer ; d, corpuscle of the outer granular layer. /3, cone ; c, as above ;
e, bacillus of cone ; f, proper cone ; g, globule of fat in the same ; h, expansion of
cone, y, from the frog, letters as above. 8, from the perch, letters as above ; i, part
at which the cone usually breaks off; k, radial fibre ; I, expansion of inner granular
layer, e, twin cones.

6. Frmtnlia membranacea. a, valve ; b, front view of frustule.

7. Emydium testudo. 7 a, isolated style ; 7 b, claw of leg.

8. Macrobiotus Hufelandii ; X ovary. 80. (Esophageal bulb ; X its framework,

9. Milnesium tardigrada. 9 a, pharynx, with -f internal buccal lobes, and f styles ; 9 b,

right posterior leg, seen from beneath,

10. Eucampia zodiaca.

11. Halteria grandinella, P., seen from above,

12. Halteria grandinetta, D., side view,

13. Kerona polyporum, E.

14. Gyges granulum, E.

15. Lacinularia socialis, E. ; 15 a, the same, more magnified,

16. Mask (labium) of JSschna (LIBELLULIDJE),

17. Spermatozoa of Triton cristatus.

18. Sarcolemma of muscle, twisted.

19-24. Navicula amphirhynchus in conjugation, Fig. 19, side view of valve of parent
frustule ; 20, frustules in an early stage of conj ugation ; 21, sporaugial sheath ; 22,
eporangial sheath with parent frustules attached; 23, sporangial frustule (front
view), with sheath and one parent frustule ; 24, side view of sporangial sheath,

25. Spermatozoa, human ; one exhibiting the so-called spermatozoal membrane,

26. Spermatozoa of rat (Mus rattus),

27. Spermatozoa of field-mouse (Arvicola (Hypudteui) arvalis),

28. Spermatozoa of rabbit (Lepus cuniculus).

29. Spermatozoa of goldfinch (Fringilla (Carduelis) elegans).

30. Spermatozoa of blackbird ( Turdus merula),

31. Spermatozoa of wood-shrike (Lanius rufus),

32. Spermatozoa of a Coleopterous Insect.

33. Spermatozoa of frog (Rana temporarid).

34. Spermatozoa of perch (Percafluviatilu).

35. Spermatic cyst of rabbit, with five globules, a, separate globule.

36. Spermatic cyst of rabbit, the cells or globules containing each a spsrmatozoon.

a, separate globule.

37. Spermatic cyst of the common creeper (bird, Certhiafamiliaris), containing a bundle

of spermatozoa.
38- a, 6, c, Staurosira construens, E.

39. Biblarium crux (leptostauron), E.

40. Goniothecium gastridium, E,

41. Periptera chlamidophora, E.

42. Periptera chlamidophora, E,

43. Aulacodiscus crux, E,

44. Goniothecium odontetta, E.

45. Actiniscus sirius, E.

46. Khizoselenia americana, E,

47. Chcetoceros didymus, E.

VARIOUS OBJECTS.

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London -lclm\in Voorst

PLATE 51.— Various Objects.

Figure

1. Coscinodiscus radiatus,

2. Cymbella Ehrenbergii.

3. Arachnoidiscus indicus.

4. Arachnoidiscus nicobaricust

5. Dictyocha fibula.

6. Epithemia gibba.

7. Podocystis americana.

8. Arihrogyra guatemalensis.

9. Acanihocystis turfacea. c, forked spicula ; d, granuliferous tentacles.

10. Acanthometra bulbosa.

11. Acineta mystacina.

12. Acineta patula.

13. Actinophrys pa radoxa, with capitate (a) and acfciniform (b) tentacles.

14. Cladoyramma californicum.

15. CoscinospTicera discoploea.

16. Disiphonia australis*

17. LiostepTiania rotula.

18. Goniolhecium Anaulus.

19. Gonioihecium barbatum.

20. Goniothecium didymum.

21. Goniothecium monodon.

22. Goniothecium navicula.

23. Goniothecium Roger sii.

24. Toxonidea Gregoriana.

25. Rhizoselenia alata.

26. Mastogloia lanceoldta.

27. Eanotia tetraodon. «, side view ; 6, front view.

28. Carpenteria balaniformis.

29. Campylopus paradoxus.

30. Cadium marinum*

31. Capillaries : a, cells of ; 6, nuclei.

32. Cercaria furcata.

33. Clavularia Barbadensis*

34. Cylindrotheca Gerstenbergeri.

35. Cymatosira Lorenziana.

36. Genicularia spirotcenia.

37. Gonatozygon Ralfsii.

38. Cosmocladium pulchdlum.

39. Attheya decora.

40. Hydrosera triquetra.

41. Plagiogramma Wallichidnum.

42. Perizonium JSraunii.

43. Dimorphococcus lunatus.

s 01UECTS.

PI 51

PLATE 52.— Various Objects.

Figure

1. Freia elegans.

2. Gerda glans.

3. Gomphogramma rupestre.

4. Heibergia Barbadensis.

5. Hydrianum ovale.

6. Hydrocoleum helveticum.

7. Transverse section of the SPINAL COED, after Lockhart Clarke, a, antero-

lateral columns (white substance) ; 6, posterior column ; c, posterior cornu
(grey substance) ; c£, anterior cornu ; 0, posterior commissure : in front is the
central canal and the anterior commissure ; /, posterior nerves ; g, anterior
nerves.

8. Hypheothrix, species of.
8*. Anacystis marginata.

9. Mastigocladus laminosus.

10. Mastigothrix ceruginosa.

11. Metopus sigmoides.

12. MiscJiococcus confervicola*

13. Liradiscus JBarbadensis.

14. Limnodictyon Rcemerianum,
16. Urnula epistylidis.

16. Pttalopus diffluens.

17. Plagiophrys cylindrica.

18. Pleurococcus vulgaris.

19. RhoicospJienia : a, curvata 6, marina.

20. Schizopus norvegicus.

21. Staurogenia quadrata.

22. StepTianosphcera pluvialis.

V \KIOI S OH.1KCTS.

PI.

PLATE 53.— Various Objects.

Figure

1. Actinomonas mirabilis.

2. Amphidinium. operculatum, with nuclear prolongations.

3. Eriosoma lanigerum.

4. Anchylostoma dysenterica, fern.

5. Amylobacter ; portion of cell of the pith of the fig-tree, lined with Amylobaeter.

6. Anophrys sarcophaga.

7. Phylloxera vastatrix.

8. Atractonema teres.

9. Asfhmatos cillaris.

10. Bicosoeca lacustris.

11. Capsosira Brebissonii.

12. Chelifer cancroides.

13. Cheyletus eruditus.

14. Colpodella pugnaac, attached to a cell of Protoeoccug.

15. Godosiga botrytis.

16. Ccelomonas grandis.

17. Cyaihomonas spissa,

18. Herpetomonas Lewisi.

19. IchthyopTiihirius multifiliis.

20. Goblet cells (p. 439).

21. Lagenceca cuspidata.

22. Mastigamoeba aspera.

23. Noctiluca miliaris.

24. Phytoptus tilice.

25. Salpingceca amphoridium.

26. Trypanosoma sanguinis.

VARIOUS OR*
3

PI 53.

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London: Jokn Van Voorst