A synopsis of the British Diatomaceæ : with remarks on their structure, functions and distribution; and instructions for collecting and preserving specimens

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THE . BRITISH DIATOMACE~:.

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OF THE

BRITS DIATOM ACG EA

WITH REMARKS

ON THEIR

STRUCTURE, FUNCTIONS AND DISTRIBUTION ;

AND INSTRUCTIONS FOR

COLLECTING AND PRESERVING SPECIMENS.

BY

THe Rev. WILLIAM SMITH, F.LS.

THE PLATES
BY
TUFFEN WEST,

MEMBER OF THE MICROSCOPICAL SOCIETY OF LONDON,

“ Naturam maximé admiraberis, si omnia ejus opera perlustraris.”—GALEN.

IN TWO VOLUMES.
VOL. I:

LONDON:

PRINTED FOR SMITH AND BECK, 6 COLEMAN STREET, CITY;
PUBLISHED BY JOHN VAN VOORST, PATERNOSTER ROW.
1853.

me
(ef

FRINTED BY TAYLOR AND FRANCIS, ©
RED LION COURT, FLEET STREET.

TO

G. H. K. THWAITES, ESQ.,

OF

PERADENIA, CEYLON,

BY WHOSE ENCOURAGEMENT I WAS INCITED TO ENTER UPON
THE FOLLOWING INVESTIGATIONS,

AND BY WHOSE AID I WAS ENABLED TO OVERCOME

THE EARLIER DIFFICULTIES OF THE STUDY,
I INSCRIBE THESE PAGES,

DESIRING THUS TO EXPRESS MY THANKS,
AND

TESTIFY MY ESTEEM,

WILLIAM SMITH.

Lewes, March 1853.

PREFACE.

THe siliceous epiderms of the Diatomacez have, of late years,
furnished the microscopist with a series of objects, not merely
attractive to the general observer, from the elegance of their forms,
but interesting to the more scientific student from the minute
complexity of their structure, whose detection and delineation call
into requisition the exercise of the most patient observation and
the skilful management of the highest powers of his instrument.
Much attention has in consequence been drawn to these minute
organisms, and the want of some English manual, containing a
classified arrangement and description of species, has been ex-
tensively felt. The present work has been undertaken to supply
this want, and owes its appearance to the enterprise and libe-
rality of the eminent opticians whose names appear on the title-
page. While securing me from loss, these gentlemen have placed
me under no inconvenient restrictions, and have left me at
liberty to render the work, as far as possible, a record of the
facts at present known with regard to the Diatomaceze. So little,
however, has been published upon the subject by English natu-
ralists, and my views of structure and classification differ so
widely from those of continental writers, with whose works [am
acquainted, that I have found it necessary to make the following

pages little else than a record of individual observation. To

v1 PREFACE.

state at length the views of foreign authors, merely to show in
what respects I differ from their conclusions, or to detail their
systems only to illustrate my own departures from their methods
of arrangement, appeared to me less likely to serve the cause of
a branch of knowledge yet in comparative infancy, than to place
before the inquirer a series of observations for which I could
personally vouch, and thus to accumulate facts, at present so
scantily supplied, upon which the future student might rest a
more complete structure of theory and classification.

How far the present work contains materials new to the
Enghsh reader will be understood when I state, that of the 224.
species included in the first sub-tribe, not more than twenty have
hitherto been recorded by our native observers ; and of the others,
a very large proportion are either for the first time described, or
can only be doubtfully referred to the outline figures given by
Ehrenberg and Kiitzing, and rendered accessible to the English
reader in the pages of Pritchard’s History of Animalcules.

But the task T had assigned to myself would have been much
less productive of results had I not been aided by the frank and
cordial co-operation of fellow-inquirers, who, by the liberal com-
munication of specimens from other localities, have enabled me
to enrich my record with some of its most beautiful and inter-
esting forms. It is my pleasing duty to acknowledge the obli-
gations I thus owe to Mrs. Griffiths of Torquay, Dr. Dickie of
Belfast, Dr. Greville of Edinburgh, Professor Williamson of Man-
chester, Mr. Edward Jenner of Lewes, and M. De Brébisson of
Falaise, whose entire herbaria in some cases, or in others ample
selections therefrom, as far as relates to the Diatomacee, have
been placed at my command. I have, however, to regret that
these collections, with one exception, contain but few species in
the genera embraced in my first volume, and that in this ex-

ception, which refers to the species from Falaise, the specimens
I ;

PREFACE, vil

reached me at so late a period that I have been unable to use
them in the nomenclature of my plates, and could only employ
them in correcting and enlarging the synonyms given in the text.

For other specimens, and many of them in a living state, I
am indebted to gentlemen, whose favours I have recorded under
the species they have respectively contributed. Among these
fellow-labourers I must not omit a special acknowledgment to
my zealous and indefatigable correspondent Chr. Johnson, Esq.
of Lancaster, who, by frequent communication of specimens col-
lected by himself and Mr. George Smith of Wray, and by the
liberal aid of books and translations, has contributed important
assistance.

Nor do I wish to leave unnoted the labours of my predecessors,
more especially those of Mr. Ralfs and Mr. 'Thwaites, to whom
is due nearly all that has been known of our British species of
Diatomaceze. How much is owing to the accurate and laborious
researches of Mr. Ralfs, will be better seen in my second volume,
which will embrace the greater number of the genera to which
he has directed his attention.

I have, lastly, to acknowledge the efficient assistance received
from my able coadjutor Mr. Tuffen West, whose accurate re-
presentations, m every case faithfully drawn from nature, have
so materially enhanced the value of my work to the scientific
student, and conferred upon it much of whatever value it may
possess, in the estimation of the general observer.

As I have not admitted anything into my pages which I have
not verified by actual observation, I have abstained from re-
cording localities unless specimens have been seen and examined
by myself. In the uncertainty which attended the nomenclature
of species, and the imperfect means of identification open to the
English observer, this course was imperative.

I have departed from the rule in one case only, Arachnoidiscus

Vill PREFACE.

Ehrenbergii, Supp. Plate XXXT. fig. 256, and on that occasion
an admirable photograph of the object left me no room for hesi-
tation as to the species intended. To avoid confusion and un-
certamty in the synonyms, I have also abstained from recording
written descriptions, and the references in every case, not other-
wise stated, are to the numbers of the plate and figure m the
work quoted; and, to preserve uniformity, I have invariably
used letters for the plate, and numerals for the figure.

Tt will be seen that I have omitted all mention of the genus
Dictyocha, whose forms, familiar to the English collector, have
hitherto been classed with the objects described in the present
work. ‘This organism has, however, little in common with the
true Diatomaceze, and the position and structure of its siliceous
skeleton altogether exclude it from the class.

[ have been obliged to defer, until the completion of the plates,
all explanation respecting the important function of Reproduction
in the Diatomacez, and a detailed examination of the contro-
versy respecting the animal or vegetable nature of these or-
ganisms ; neither of these subjects could have been fully discussed
without a reference to many of the figures to be given in my
second volume, and I have thought it better to postpone these
topics, however immediately interesting, than to enter upon
explanations that must necessarily have been imperfect or unin-
telligible.

CONTENTS OF THE INTRODUCTION.

Page

Section [. The Habitats and general Appearance of the Dia-
tOMmacen ey Sar Re oo ere yc Oe XI

I]. Structure of the Siliceous Epiderm of the Diatoma-
CeousvErustulerse pes icles econ sal eons XLV,

III. Internal Structure and Cell-contents of the Diato-
MACCOUSETUSGULCS Ai aehc. ce Geno mu Culn cane ueeeer me 1K
LV! Movements of the Diatomacer: “. 2. j.0 2.) XxIL
V. Self-division in the Diatomacee . . . . . =. . XXiIV
VI. Terminology and Classification . . . . . . . XxXvil

VII. On Collecting and Preserving Specimens of the Dia-
tomaces eA. hss) Ce) eh

NE OCT Orne

Section I.
Hasitrats AND GENERAL APPEARANCE OF THE DIATOMACER.

‘Tue Diatomaceze are readily distinguished from the Desmidice,
the Palmellaceze, and other unicellular Algae, by the possession of
an epidermal covering of silex, which renders their forms inde-
structible by the ordinary agents of decomposition. They are
all exceedingly minute, and require the human eye to be aided
by the various appliances of the optician’s art, that their beauti-
ful forms may become objects of admiration and study. They
inhabit the sea or fresh water, but the species peculiar to the
one are never found in a living state in the other locality,
though there are some which prefer a medium of a mixed
nature, and are only to be met with in water more or less
brackish. The latter are often found in great abundance and
variety in districts occasionally subject to marine influences, such
as marshes in the neighbourhood of the sea, or the deltas of rivers,
where, on the occurrence of high tides, the freshness of the water
is affected by percolation from the adjoining stream, or more
directly by the occasional overflow of its banks. Other favourite
habitats of the Diatomaceze are stones of mountain streams or
waterfalls, and the shallow pools left by the retirmg tide at the
inouths of our larger rivers. They are not however confined to
the localities I have mentioned,—they are in fact almost ubiqui-
tous, and there is hardly a roadside ditch, water-trough or

xii INTRODUCTION.

cistern which will not reward a search, and furnish specimens
of the tribe.

The mdestructible nature of their epiderm has also served to
perpetuate the presence of these forms m numerous localities,
from which their living representatives have long since dis-
appeared. Districts recovered from the sea, im the present or
other periods of the earth’s history, frequently contain myriads
of such exuvize forming strata of considerable thickness. Such
deposits have been found in Bohemia, in the neighbourhood of
Berlin, in various districts in Italy, and in several of the American
States. The city of Richmond in Virginia is said to be built
upon a stratum of Diatomaceous remains 18 feet in thickness,
and extensive tracts in the Arctic Regions have been found
covered with similar relics of a former vegetation.

Nor are we without examples, though on a less extensive
scale, in our own country. ‘The ancient site of a mountain lake
in the neighbourhood of Dolgelly, localities of a somewhat similar
kind near Lough Island-Reavey, in Down, and Lough Mourne,
in Antrim, have furnished large supplies of some of the forms
described in the present work. Several deposits of a like kind
have been met with in Scotland, and have also contributed to en-
rich the present volumes. The extreme minuteness of the organ-
isms which have furnished such remains, and the hardness of their
material, have rendered the substance formed by their aggrega-
tion, a useful agent in the mechanical arts, in which it has been
employed to confer a polish upon hard surfaces. It is from this
circumstance that the material known as Tripoli derives its value
as a polisher of metals; and the Dolgelly deposit has to some
extent been employed for a similar purpose.

One of the most singular instances of the preservation of
Diatomaceous forms occurs in regard to Guano, so largely im-
ported as a manure from Peru and Africa. This material is
found to contain a large number of the siliceous coverings of
these minute organisms, which have been swallowed by the ma-
rine birds frequentmg the spots from which the Guano is pro-
cured, have survived the process of digestion to which they
were at first submitted, and the ages durmg which they have
been imbedded in decomposed or decomposing matter, and now

INTRODUCTION. xill

serve by the beauty of their forms to delight the microscopist,
and by the property which their presence imparts to the Guano,
to contribute to the fertility of our pastures and the growth of
our cereals. It is well known that the latter plants contain a
large amount of silica in the structures of their stem and leaves ;
it is therefore probable that the value of this manure may
some degree depend upon the presence of these minute organic
remains, which may thus confer upon the Guano a quality ren-
dering it eminently conducive to the healthy growth of such
crops.

When occurring in strata of a fossil or subfossil character, as
the deposits of Dolgelly, Richmond, and Lough Mourne, the
epiderms of the Diatomaceze appear as a white or cream-co-
loured powder; but their living masses present themselves as
coloured fringes attached to larger plants—or forming a cover-
ing to stones or rocks in cushion-like tufts—or spread over
their surface as delicate velvet—or depositing themselves as a
filmy stratum on the mud—or intermixed with the scum of
living or decayed vegetation floating on the surface of the water.
Their colour is usually a yellowish brown of a greater or less
intensity, varying from a light chestnut in individual specimens,
to a shade almost approaching black in the aggregated masses.
Their presence may often be detected without the aid of a mi-
croscope, by the absence, in many species, of the fibrous tena-
city which distinguishes other plants: when removed from their
natural position, they become distributed through the water,
and are held in suspension by it, only subsiding after some little
time has elapsed.

The frustules of the Diatomacez, as the individual organisms
have not inaptly been denominated, are either free, adherent, or
variously aggregated : in Witzschia, Navicula and others, we have
the frustules absolutely free ; m Apithemia, Cocconeis, &c., they
are usually adherent. One mode of aggregation is that of a
ribbon-like filament of indefinite length, as in Fragillaria, &e. ;
another, that of a zigzag chain, in which the frustules cohere
only by their angles, as in Grammatophora, Diatoma and others.
In some species the Diatom is provided with a gelatinous
pedicel or stipes by which it is united with other frustules, and

X1V INTRODUCTION.

maintains a connection with a foreign body; we have this form
in Synedra and Gomphonema, &c. In others, again, it is enclosed,
with multitudes of its confreres, in a gelatinous or membrana-
ceous thallus, as in Schizonema, Hucyonema and their allies, and
the aggregation of the frustules in such cases sometimes rivals
in form and size the branching filaments of the larger Algz.
Upon submitting livmg Diatomacez to a microscopic exami-
nation, their forms are found to be exceedingly diversified, though
the mineral nature of their epiderm confers upon them a general
character which reminds the observer of morganic rather than of
vegetable or animal productions. ‘Thus prismatic and quadri-
lateral forms are among the most general; linear, crescent, or
boat-shaped outlines are not unfrequent ; while indidivuals grace-
fully curved ina sigmoid manner, and others resembling minia-
ture shields or circular discs, occasionally present themselves.

Srcrion II.

STRUCTURE OF THE StuicEous EprpERM OF THE DIATOMACEOUS
FRUSTULE.

To ascertain the true form and structure of the Diatomaceous
frustule requires a careful microscopic examination, not only
of livmg, but of desiccated or prepared specimens. Indeed it
is only after an examination of the latter, that the true character
of the living frustule can be understood. I shall therefore
commence my description of the structure of these organisms
by a reference to frustules which have been deprived of their
softer parts, either by submitting them to the action of fire, or
to the corrosive influence of an acid.

The epiderm of the Diatom consists of two siliceous plates or
valves, usually of the most perfect symmetry. When first pro-
duced, these valves are closely applied to each other, and the line
of junction forms a suture along which the valves readily sepa-
rate during the process of self-division which speedily follows the
perfect formation of the cell. It seems to be a law with these
organisms, that no portion of the internal cell-membrane can be

INTRODUCTION. XV

exposed to the free action of the surrounding water, without
secreting a siliceous epiderm; the moment the valves become
separated in the process of self-division, we consequently find
that the secretion of a third plate of silex commences. This
plate forms a band between the valves, and will for convenience
sake be afterwards spoken of as the Connecting Membrane.
As self-division is continually going on while the frustules are
in a healthy or growing state, it is rare to find a specimen in
which the valves are not in some degree separated, and con-
sequently in which there is not more or less of a connecting
membrane.

But that no such membrane exists on the first production of
the frustule is obvious, upon the examination of a specimen in
which self-division is just completed, as in Pl. VIII. fig. 59 d;
Pl. XVIII. fig. 167 d; and Pl. XXVII. fig. 235 d, compared
with Pl. VIII. fig.596; Pl. XVIII. fig. 1696; and Pl. XXVII.
fig. 235 4, in which the process has made some advance. The
process of self-division will be described hereafter ; the present
remarks are intended to show that the Epiderm of the Diatom,
strictly speaking, consists of only two parts, the connecting
membrane being an addition consequent upon the development
which attends the growth of the frustule.

Along the line of suture in disciform or circular frustules, but
more generally at the extremities of the valves only, when the
Diatom is of an oblong, linear, or elongated form, there exist
perforations in the silex, which permit the surrounding water to
have access to the surface of the imternal cell-membrane. The
formation of silex seems occasionally to be arrested in the neigh-
bourhood of these spots, and the connecting membrane is in
consequence either wholly or partially interrupted at such places.
‘Thus, after the mternal cell-membrane is removed by acid, when
it often happens that the valves fall away from the connecting
membrane, the latter separates into two parts, and the frustule
has in consequence been described as consisting of four plates.

The interruptions in the siliceous epiderm, to which reference
has just been made, are usually apparent as slight depressions
at the extremities of the frustule; and the appearances they
present have been denommated “ puncta” by Mr. Ralfs. In

XV1 INTRODUCTION.

some species these interruptions are more numerous, being found
along the entire Ime of suture, and are often connected with
minute canals, hollowed out between the siliceous epiderm and
internal cell-membrane, and apparently formed by waved flexures
of the epidermal envelope. ‘These are noticed under the genus
Epithemia, p. 11. They are very conspicuous in Fpithemia
longicornis, Supp. Plate XXX. fig. 247, and form distinctive cha-
racters in the genera Surirella and Campylodiscus. I have em-
ployed the term “ Foramina,”’ in reference to these perforations
in the siliceous epiderm, and the epithet ‘Canaliculi,’ to de-
signate the grooves into which they occasionally open.

‘The connecting membrane, being of later formation, is usually
less firmly siliceous than the epidermal valves, and rarely pre-
sents much complexity of structure. Not so with the valves
themselves; we have here the greatest variety of form and
diversity of structural arrangement.

These variations in form and structure will be best understood
by an inspection of the figures, and will be noticed more par-
ticularly under each genus. I shall confine my remarks at pre-
sent to a few general characters.

In all, we find the valves presenting a surface of a greater or
less degree of convexity. This follows as a necessary conse-
quence, from their enclosing, when applied to each other, the
space occupied by the internal cell. This convexity is often
that of a regularly curved surface, forming a segment of a circle
of a greater or less radius. The segment is occasionally that of
a perfect hemisphere, and the valves, when applied to each
other, form a miniature globe; but more frequently the curva-
ture is slight, and extends over a part of the valve only, which
then appears as a portion of a hollow tube, closed at one end,
and which may be either cylindrical or compressed, triangular
or quadrilateral.

The imtimate structure of the valve presents an amazing
variety, in every genus, and almost in every species, offering
distinct features, which serve as the best and most facile means
of distinction and identification. Strize or lines frequently mo-
niliform, dots arranged in a radiate or concentric manner, and
minute divisions presenting perfectly hexagonal outlines, are

INTRODUCTION. XVil

among the most frequent appearances. Great diversity of opi-
nion has prevailed respecting the nature of these markings, and
various functions have been assigned to them, as they have been
regarded as apertures, protuberances, or depressions. I am,
however, disposed to regard them all as modifications in the
arrangement of the silex of the valve, arising from the mode of
development peculiar in each case to the membrane with which
the silex is combined. It is a well-established fact, that all in-
crease in vegetable and animal tissues takes place by the pro-
duction and addition of cells ; and the law seems to prevail even
in the formation of the envelopes of the minute organisms with
which we are now concerned. Certainly no one can look at the
structure exhibited by the siliceous valves of Zriceratium Favus,
PL. V. fig. 44, and those of Lsthmia enervis or I. nervosa, to be
given in the second volume of the present work, without feeling
assured that he has before him the representation of a cellular
membrane, precisely homologous with the epidermal tissues of
many vegetable organs. An object-glass of sufficient power
and definition shows the same structure in the valves of many
species of Plewrosigma; and the generalization is at once forced
upon the observer, that the valvular markings in every case arise
from modifications of cellular tissue,—a conclusion which a
further and closer examination does much to confirm. In no case
have I been able to satisfy myself of the existence of perforations
in the general surface of the valves ; and the existence of depres-
sions or elevations (except in a few cases, when such appearances
arise from the wavy outline of the surface,) seems to me to be
equally problematical; but no difficulty presents itself to the
supposition, that the moniliform strize of Hpithemia, Navicula,
and others, the circular markings of Coscinodiscus eccentricus,
Plate HI. fig. 38, and the irregular star-like structure of Aypo-
discus Argus, Plate IV. fig. 39, are all modifications of cellular
tissue ; and even in the costz of Pinnularia and the unresolvable
strie of Hupodiscus sculptus, Plate IV. fig. 42, and others, it is
not difficult to conceive that we have confluent cells whose union
gives rise to the appearance of lines or bands.

With the appearances thus arising from the cellular structure
of the tissue with which the silex is combined, we must not con-

b

XVill INTRODUCTION.

found those which are caused by the presence of Canaliculi, to
which reference has already been made; nor must we overlook
others, which, although connected with the structure of the valve,
arise from the absence of cells. Thus m many genera the valve
is notably distinguished by the presence of a longitudimal band
of silex, free from markings, and widened into small expansions
at the centre and extremities, or at the extremities only. ‘This
band is simply a portion of the tissue in which the silex is de-
posited in a solid mass, and is probably designed to give firm-
ness to the valve. At the expansions of this band the silex
is still further accumulated, and forms Nodules, which also
strengthen the epidermal envelope.

That these expansions are not perforations in the valve, as
alleged by Ehrenberg, and acquiesced in by Kiitzing, might be
shown in various ways. ‘The internal contents of the frustule
never escape at such points when the frustule is subjected to
pressure, but invariably at the suture or the extremities, where
the Foramina, already described, exist. Nor does the valve,
when fractured, show any disposition to break at the expansions
of the central le, as would necessarily be the case were such
points perforations, and not nodules. Moreover, the central
band of silex is itself frequently traversed by a narrow line, which
arises from the confluence of a series of cells, which thus form a
minute tube; but this tube invariably ends in a rounded ex-
tremity at the central and terminal nodules, and does not pass
into an opening or aperture in the valve. A reference to Plate
XIX. fig. 166. will illustrate these remarks. The bending down
of this tube, and the thickening downwards of the silex at the
nodules, give the semblance of depression to the surface of the
valve at such places. But I am disposed to think that this is
merely an optical appearance ; and amy at all events assured that
no perforation exists at such poimts, and that the terms applied
to these nodules by different authors, implying that they are
openings or ostiola, are altogether madmissible.

INTRODUCTION. X1X

Section III.

INTERNAL STRUCTURE AND CELL-CONTENTS OF THE DIATO-
MACEOUS FRUSTULE.

I now proceed to describe the living frustule, some of the
appearances presented by which can only be understood by a
previous acquaintance with the structural character derived from
an examination of the siliceous envelope.

A careful study of these organisms in a fresh state is neces-
sary to enable the observer to arrive at a correct idea of their
true character. The species are lable to material alterations
when removed for any length of time from their natural localities ;
the lapse of a few days, and sometimes of a few hours, bemg
sufficient to modify or altogether change the colour and arrange-
ment of the cell-contents, and to suspend the peculiar movements
which in many species accompany their living condition. They
must, therefore, be examined under favourable circumstances,
or our conclusions may be of the most erroneous kind; and a
neglect of these precautions has undoubtedly led in some cases
to grave errors respecting the structure, and even the nature, of
the Diatomaceous frustule. As I look upon these organisms as
unicellular plants, I consequently regard the siliceous valves as
investing a closed membranous sac or cell. Nor is this a matter
of conjecture and analogy only. In some cases I have seen
unmistakeable indications of the existence of this membrane,
which I have noticed to contract around the cell-contents upon
the death of the cell; and in one species, Stawroneis pulchella,
Plate XIX. fig. 194, in which the membrane in question appears
to possess an unusual degree of firmness, the siliceous valves, after
a slight maceration in acid, may be seen to fall away from the
internal membrane, and to leave the latter unaltered in form.
Moreover, the experiments and authority of Professor Bailey
place the existence of an internal membrane beyond all doubt.
This acute observer states that, “If hydrofluoric acid is applied
to recent Diatomacez, the shell soon dissolves, leaving distinct
internal, flexible cell-membranes, retaining the general form of

b2

XX INTRODUCTION.

the shells.” (From Silliman’s Journal for May 1851, quoted
in Ann. Nat. Hist. 2nd Ser. vol. viii. p. 157.)

The usual colour of the living frustule I have stated to be a
yellow, with a brown or greenish shade of a greater or less m-
tensity ; this colour is found to arise from the contents of the
cell, which consist of a mucilaginous fluid, in which float numerous
minute granules, generally accumulated in thin layers towards
the internal cell-walls. When the frustule is so turned that this
layer of endochrome is presented edgeways to the eye, the gra-
nules appear to be chiefly aggregated into two plates, applied to
the opposite sides of the frustule; and when self-division is in
progress, and the cell-contents are divided into two portions,
such a separation or temporary aggregation of the endochrome
must necessarily ensue; but in the simplest condition of the
frustule the contents are diffused over the entire surface of
the cell-walls, precisely as may be seen in the cells of many
of the larger Algze, or of some water plants of a higher order,
as in the leaves of Hydrocharis Morsus-rane and others.

The endochrome of the Diatomaceous frustule is not, however,
spread with uninterrupted regularity over the entire wall of the
cell; at a spot exactly in the centre of the frustule it is usually
absent, bemg aggregated in a narrow line or ring around
a circular space occupied by a transparent vesicle, the nucleus
or cytoblast of the cell, which frequently encloses an evident
nucleolus. Nor are we to regard the endochrome as being
always confined to the surface of the cell-wall. It is often diffused
throughout the entire cavity, in lines radiating from the nu-
cleus. Such a disposition frequently occurs in Plewrosigma
and others, and is invariably found in Navicula elliptica. (See
Frontispiece, fig. CLIT.)

In most species several smaller globules, in addition to the
central vesicle, are found occupying certain fixed positions within
the cell; these are probably special secretions from the cell-
contents, of an oily nature ; and I am disposed to attribute to
them the origin of the peculiar odour exhaled from the frustules
in the process of burnmg. ‘The number of these globules is
frequently four, often placed near the extremities, or, more rarely,
clustered around the central vesicle. Professor Kiitzing has ex-

INTRODUCTION. XX1

amined these globules with the greatest care, and has convinced
himself of their oily nature. He regards them as representing
the amylaceous secretions of the Desmidiez and Confervee, and
the starch-granules of the cotyledons of the higher vegetables.
(Bacillarien, p. 23.)

A distinct movement of the granular particles of the endo-
chrome, closely resembling the circulation of the cell-contents in
Closterium Lunula, noticed by My. Ralfs (British Desmidiez, Pre-
face, p. xxi.), and which I have frequently detected in the same
species, has occasionally fallen under my notice in some of the
larger species of Diatomacece.

In Surirella biseriata, Plate VIII. fig. 57, this motion has
been more especially apparent ; but I have also observed it take
place in Miteschia scalaris, Plate XIV. fig. 115, and Campylo-
discus spiralis, Plate VII. fig. 54.

This circulation has not, however, the regularity of move-
ment so conspicuous in the Desmidiez, and is of too am-
biguous a character to furnish data for any very certain conclu-
slons, save one, viz. that the Diatom must be a single cell, and
cannot contam a number of separate organs, such as have been
alleged to occupy its interior; simce the endochrome moves
freely from one portion of the frustule to another, approaching
and receding from the central nucleus unimpeded by any inter-
vening obstacle.

Of the chemical composition of the endochrome, I am at pre-
sent unable to offer a satisfactory analysis. Professor Frankland,
of Manchester, who kindly consented to direct his attention to
the chemical constituents of these organisms, but whose engage-
ments have hitherto prevented him from completing the neces-
sary investigations, informs me that a large amount of iron exists
in the state of a silicate or protoxide in the siliceous epiderm ;
and he attributes to its presence the brown colour which is
assumed upon exposing the Diatoms to the influence of a
moderate heat, the protoxide of iron, by the gradual absorption
of oxygen, bemg converted into brown peroxide of iron, which
assumes a redder tinge upon bemg more strongly heated.

Of the behaviour of the endochrome under the influence of
certain reagents, | may merely remark at present, that dilute

XX1L INTRODUCTION.

tincture of iodine causes the internal membrane to contract
upon the cell-contents, and converts these, from the golden yel-
low which they exhibit in some species, into a bright green ; and
that a weak solution of sulphuric acid, while it effects the same
contraction in the cell-wall, gives to the contents, which have
been previously treated with iodine, a dark brown hue.
Alcohol, on the other hand, as in the case of vegetable cells
in general, dissolves the utricle and its contaimed endochrome,
or, at all events, entirely removes their colour, and leaves their
siliceous epiderm in a state of perfect transparency. It does
not, however, dissolve the envelope in which the frustules of the
frondose forms are imbedded, nor the filamentous stipes or
gelatinous cushions to which other species are attached.

Section IV.

Movements oF THE DIATOMACES.

One of the most striking circumstances connected with the
living frustule, is the smgular motion which most of the free
species exhibit.

This motion is of a peculiar kind, being generally a series of
jerks, producing a rectilinear movement in one direction, and a
return, upon nearly the same path, after a few moments’ pause,
by another series of isochronal impulsions.

The movement is evidently of a mechanical nature, produced
by the operation of a force not depending upon the volition of the
living organisms. An obstacle m the path is not avoided, but
pushed aside; or, if it be sufficient to avert the onward course
of the frustule, the latter is detained for a time equal to that
which it would have occupied in its forward progression, and
then retires from the impediment, as if it had accomplished its
full course.

There is certamly no character of animality in the movement ;
and the observer familiar with the phzenomena of life in the ear-
her stages of vegetable existence, is constramed to seek a counter-
part in the involuntary motions of the filaments of the Ose7//a-
foriee, or of the gemmiparous spores of the vc and Conferve.

INTRODUCTION. XXili

The movements of the Diatomacee appear rapid and viva-
cious under the microscope ; but it must be remembered that the
high powers usually employed in the observation of these mi-
nute organisms magnify their motions as well as their bulk. I
have noted the movements of several species with the aid of an
eye-piece micrometer and a seconds watch, and found that one
of the most rapid, viz. Bacillaria paradora, moved over zooth
of an inch in a second; Pinnularia radiosa, one of the slowest,
over 3qooth of an inch in the same time; and that the same
period was occupied by Pinnularia oblonga m traversing zp yoth
of an inch, Mtzschia linearis 335th of an inch, and Plewrosigma
strigosum zzooth of an inch. Or, expressing the spaces and
times by other units, we find that the most active required some-
what more than three minutes to accomplish movements whose
sum would make one inch, and the slowest nearly an hour to
perform the same feat.

These movements are usually noticed only in the free species
of the class, as in those belonging to the genera Navicula, Nitz-
schia, and others, and especially in the more minute or younger
individuals. Motion is not, however, confined to these, but may
at times be detected in other forms, and even the frustules. of
attached species, as those of Gomphonema, when forcibly sepa-
rated from their stipes, occasionally exhibit an evident tendency
to change their position. The movements in the latter are, how-
ever, exceedingly languid, and have nothing of the isochronism
so notable in the others.

Of the cause of these movements I fear I can give but a very
imperfect account. It appears certain that they do not arise
from any external organs of motion. The more accurate instru-
ments now in the hands of the observer have enabled him con-
fidently to affirm, that all statements resting upon the reve-
lations of more imperfect object-glasses, which have assigned
motile cilia, or feet, to the Diatomaceous frustule, have been
founded upon illusion and mistake. Among the hundreds of
species which I have examined in every stage of growth and
phase of movement, aided by glasses which have never been sur-
passed for clearness and definition, | have never been able to
detect any semblance of a motile organ; nor have I, by colour-

XX1V INTRODUCTION.

ing the fluid with carmine or indigo, been able to detect m the
coloured particles surrounding the Diatom, those rotatory move-
ments which indicate, in the various species of true infusorial
animalcules, the presence of cilia. I am constrained to believe
that the movements of the Diatomaceze are owing to forces
operating within the frustule, and are probably connected with
the endosmotic and exosmotic action of the cell. The fluids
which are concerned in these actions must enter and be emitted
through the minute foramina at the extremities of the siliceous
valves ; and it may easily be conceived, that an exceedingly small
quantity of water expelled through these minute apertures
would be sufficient to produce movements in bodies of so little
specific gravity.

If the motion be produced by the exosmose taking place alter-
nately at one and the other extremity, while endosmose is pro-
ceeding at the other, an alternating movement would be the
result in frustules of a linear form; while im others of an ellip-
tical or orbicular outline, in which foramina exist along the en-
tire line of suture, the movements, if any, must be irregular,
or slowly lateral.

Such is precisely the case. The backward and forward move-
ments of the Vaviculee have been already described ; in Surzrella
and Campylodiscus the motion never proceeds farther than a lan-
guid roll from one side to the other; and im Gomphonema, in
which a foramen, fulfilling the nutritive office, is found at the
larger extremity only, the movement is a hardly perceptible
advance in intermitted jerks in the direction of the narrow end.
The subject is, however, one involved in much obscurity, and is
probably destined to remain, for some time to come, among the
mysteries of nature, which baffle while they excite mquiry.

Section V.
SELF-DIVISION IN THE DIATOMACES.

This process, by which asingle cell is converted into two per-
fect cells, is by no means peculiar to the Diatomacez, but pre-
vails extensively in the vegetable kingdom, if indeed it be not

INTRODUCTION, XXV

the ordinary mode of increase in all such tissues. Certain it is,
that in the great class of unicellular Algze, it is the universal
mode of growth and multiplication. It, however, presents several
peculiarities in the organisms with which we are now concerned,
and is also so readily noted and followed in all its stages in the
Diatomacee, that a close observance and clear comprehension
of the process in their case may illustrate and guide inquiry in
other tribes.

The first step in the process of self-division in the Diato-
maceous frustule, is the fission of the internal cell, probably by
the doubling-in of its membranous wall, and consequently the
separation of the endochrome or cell-contents ; the central vesicle
or cytoblast also dividing into two parts, which remove to a little
distance from each other; these movements bemg simultaneous
with a retrocession of the epidermal valves and the formation of
the siliceous connecting-membrane already described. In the
centre of the enlarged frustule, in exact apposition to the original
valves, and closcly applied to them, there are now formed two
new valves, covering the surface of the cell-membranes along the
line of fission. The divided portions of the endochrome spread
themselves along the membrane which is embraced by the new
valves, and there result two half-new frustules, bound together
by the connecting-membrane, generated during the process we
have described. 'The figures of self-division given throughout the
plates will serve to illustrate this description ; and more especially
those in Pl. VIII. fig. 59d, Pl. XV. fig. 126 d, Pl. XXII. fig. 216 d.

Durmg the healthy life of the Diatom, the process of self-
division is being continually repeated; the two half-new frus-
tules at once proceed to divide again, each into two frustules,
and thus the process continues. I have been unable to ascer-
tain the time occupied in a single act of self-division ; but sup-
posing it to be completed in twenty-four hours, we should have,
as the progeny of a single frustule, the amazing number of one
thousand millions in a smgle month: a circumstance which will
in some degree explain the sudden, or at least rapid, appearance
of vast numbers of these organisms, in localities where they were,
but a short time previously, either unrecognized, or only sparingly
diffused.

XXV1 INTRODUCTION.

‘The new valves formed during the process of self-division or-
dinarily appear exact counterparts in form and size of the valves
of the original frustule ; but a careful examination of the pro-
cess in the filamentous species has led me to conclude that a
slight enlargement occasionally takes place in the new valves,
thus causing a widening of the filament.

This increase is however so small, that in a filament of many
hundred frustules, the enlargement is scarcely appreciable.
The rapid attenuation represented by some authors in the fila-
ments of the Fragi/arie must therefore be attributed to the
deceptive appearance presented by a compressed band when
slightly twisted, the semblance of attenuation being thus given
to the portions which are presented in an oblique direction to
the eye of the observer.

The increase in the new valves, although slight, will however
sufficiently account for the varying breadth of the bands in the
filamentous species, and the diversity of size in the frustules of
the free forms, without obliging us to suppose that a growth or
aggregation takes place m the siliceous valve when once formed.
Starting from a single frustule, it will be at once apparent, that
if its valves remain unaltered in size, while the cell-membrane
experiences repeated self-division, we shall have two frustules
constantly retaming their original dimensions, four slightly
increased, eight somewhat larger, and so on, in a geometrical
ratio, which will soon present us with an mnumerable multitude
containing individuals in every stage, but im which the larger
sizes preponderate over the smaller; and such are the circum-
stances ordinarily found to attend the presence of large numbers
of these organisms.

It is hardly necessary to remind the student acquamted with
the general laws of the vegetable kingdom, that this multiph-
cation of the Diatomaceous frustule is not a true reproduction
of the species, but merely a growth or extension of the original
frustule with which we may suppose self-division to originate ;
and as the myriads of cells which constitute the entirety of the
largest sea-weed, are regarded in their aggregation as forming
but one plant, so may we consider the thousand millions into
which a single month’s growth has multiplied the original frus-

INTRODUCTION. XXVll

tule, as belonging to the individuality of the first organism in
the Diatomaceous chain of being.

With the free species of the Diatomacee the analogy may
seem a forced one; but its correctness is at once apparent, if
we ascend to more complex combinations in the filamentous
and frondose genera, no very obvious difference existing be-
tween the union of cells in Fragilaria and those of many spe-
cies of the Conferve; or their aggregation in Schizonema, and
various forms of the larger Aleze. The most important distinction
between the combination of cells in the two cases, is the greater
readiness with which the connection is dissolved im the Diato-
mace and the retention of mdependent life in each separated
cell; but as we descend in the scale to the lower Algw, and
approach the Ulvacee or Palmellacee, even this difference dis-
appears, and the smallest portion of the frond, even a simple
cell, in these forms enjoys the same independent vitality and
power of increase as the Diatomaceous frustule.

The increase by self-division in the Diatomacez is therefore
not a renewal, but a mere extension of individual life; and the
process has been justly defined by Mr. Thwaites, in the analo-
gous case of the Palmellacee, as an act of Gemmation rather
than Reproduction.

“Tf we duly consider this fact,” remarks this acute and zeal-
ous student of nature, “ how much does it exalt the lower tribes
of plants in our estimation! since we may contemplate an indi-
vidual plant of them not as the single phyton—not as the single
frond—not as the single cell—but as the aggregate, it may be,
of thousands of these ;—view it occupying as much space, and
exercising as great an influence in the ceconomy of nature, as
the largest forest tree.” (Annals of Natural History, 2nd Series,
vol. u. p. 315.)

Section VI.

‘ERMINOLOGY AND CLASSIFICATION.

The circumstances attendant upon the self-division of the
Diatom furnish means for fixing the termmology applied to the

XXVlil INTRODUCTION.

different aspects of the frustule. It would have been desirable
to have here adopted the terms employed by former writers,
especially by those distinguished authors who have led the
way im the study of these organisms; but this course is pre-
cluded by the circumstance that these writers have employed
terms which imply views of the structure and nature of the
Diatomaceous frustule that are now altogether admissible, or
at all events at variance with the conclusions of the present
writer.

Thus, the terms ventral and dorsal, employed by Ehrenberg,
would be clearly inconsistent, if not unmeaning, when applied
to the different aspects, or parts of a plant. The terms primary
and secondary sides, adopted by Kiitzing and others, are not
open to the same difficulty ; but they labour under this objection,
that they have not been employed by Mr. Ralfs, the highest
English authority upon the subject. I shall therefore adopt the
nomenclature of the last-named writer, as the most convenient
for the English student, and use the term “front view,” to de-
note the aspect of the frustule. when the valvular suture, or the
line along which self-division takes place, is turned towards the
observer; and the term “side view,” when the centre of one
valve is directed to the eye.

Even these terms will require modification when applied to
some of the more complex and irregular forms; but im general
their meaning will be sufficiently obvious, and special cases will
be noticed as they present themselves.

Self-division also supplies circumstances and. distinctions,
which appear to me most suitable in the present state of our
knowledge, on which to found a generic arrangement of the
Diatomacee. ‘The circumstances which accompany the Repro-
duction of these organisms are so imperfectly ascertained, and
that in so few species, that it is impossible to employ them with
advantage in a generic arrangement. Self-division seems to me
to come next in order, as a most important function connected
with increase and growth, and to supply the necessary variety
of phenomena on which to ground our sectional divisions.

I have therefore separated those forms where self-division is
accompanied by the secretion of a permanent gelatinous or

INTRODUCTION. XX1X

membranaceous envelope, in which the frustules are subsequently
imbedded, from those in which such secretion is altogether
absent, or is represented merely by a cushion or stipes, to which
the frustules are attached by a small portion of their surface ;
and I have placed the latter, as of simpler organization, in my
first tribe, arranging the genera belonging to it into sub-tribes,
depending upon the permanency or otherwise of the connecting-
membrane, another product of the self-dividing process. ‘This
enables me to place apart those genera whose species present us
with frustules in which the union of the cells is dissolved almost
immediately upon the completion of self-division, as well as those
where a cushion or stipes still maintains a kind of indirect in-
dividuality in the divided frustules, from the genera in which
the cells cohere after gemmiparous increase, and by such co-
herence form filaments of various lengths and forms, allotting
the latter to sub-tribes which respectively present a compressed
filament, a zigzag chain, or a cylindrical thread. In the second
tribe, mcluding those genera which have frondose forms, I find
characters for my sub-tribes in the nature of the frond and the
arrangement of the frustules.

I do not propose this arrangement as free from exceptions or
even serious defects, but I have adopted it in preference to those
hitherto given, as brmging more frequently together forms
allied in structure and mode of growth, and as being at the
same time more strictly in accordance with the external physi-
ognomies of these organisms, and therefore more likely to be
apprehended by the inquirer entermg upon the study of this
department of nature. A wider study of Diatomaceous forms
will doubtless lead to more accurate and more natural generali-
zations.

Section VII.

On CoLLECTING AND PRESERVING SPECIMENS OF THE
DIATOMACE.

I have already described the various localities in which the
Diatomacez ordinarily abound. Supposing the observer to be

XXX INTRODUCTION.

acquainted with their general appearance, it remains for me to
point out the method to be observed in their collection, and to
furnish the student with a few directions as to their subsequent
preservation.

Let him provide himself in the first place with the necessary
apparatus. or the field, this includes a good stock of small
wide-mouthed bottles, that each gathermg may be kept perfectly
distinct ; a long rod or stick, to which can be attached a small
muslin net; a cutting hook, of about three inches in length ;
and a broad flat spoon: the first, to collect such specimens as
float upon the surface, or are held in suspension by the water ;
the second, to remove the larger Algze which may be covered
with parasitic Diatoms ; and the third, to skim the surface of the
mud for those which he at the bottom of the pool.

He will probably find, notwithstanding every care, that his
specimens are mixed with much foreign matter, in the form of
minute particles of mud or sand, which impair their value, and
interfere with observation, especially with the higher powers of his
instrument. These substances the student may remove in various
ways; by repeated washings in pure water, and at the same
time, profiting by the various specific gravities of the Diatoms
and the intermixed substances, to secure their separation ; but
more particularly, by availing himself of the tendency which the
Diatomaceze, in common with all growing plants, possess, of
making their way towards the light. The free forms may be
thus procured im a tolerably clean state; all that is necessary
being, to place the gathering which contains them in a shallow
vessel, and leave them undisturbed for a sufficient length of
time in the sunlight, and then carefully to remove them from
the surface of the mud or water.

Having performed these operations, which a little practice will
render comparatively easy and generally successful, the next pro-
ceeding is to preserve the specimens in such a manner as to
render them suitable for examination by the microscope at any
future time. ‘This may be done in various ways, according to
the nature of the species and the precise object desired.

The simplest method, and the one most generally useful to
the scientific observer, is simply to dry the specimens upon small

INTRODUCTION. XXxl

portions of talc, which can at any time be placed under the
microscope, and examined without further preparation ; and this
mode possesses one great advantage, that the specimens can be
submitted without further preparation to a heat sufficient to
remove all the cell-contents and softer parts, leaving the siliceous
epiderm in a transparent state. But this method will not preserve
the natural appearance of the filamentous, stipitate, or frondose
forms ; nor will it satisfy the amateur who desires a specimen
for his cabinet, and demands a mounting of a permanent kind
and neat appearance.

To meet these requirements, it is necessary that the specimen
should be preserved in fluid or balsam. The modes of mounting
objects im both these ways are best learnt by the examination of
specimens thus prepared; and the manipulation required can
only be successfully acquired by practice.

I have never found written or verbal directions of much real
value, and shall confine myself to a few hints, which may sup-
plement the discernment and patience of the operator, but can-
not supersede their presence nor supply their absence.

The walls of the artificial cell for the filamentous and stipitate
forms, I invariably form of litharge (protoxide of lead) and japan-
ners’ gold-size ; and I attach the thin glass covers with a cement
of gold-size, mixing with it a little lamp-black, to give a darker
colour to the last coating applied.

The fluid I employ is distilled water, without any mixture
whatever, having found all compound fluids not merely unneces-
sary, but ijurious.

If the filamentous and stipitate forms are not, however,
mounted in a fresh state, the frustules separate from each other,
part from their stipes, and lose their characteristic appearance.
‘To remedy these inconveniences, I immerse such specimens as
cannot be placed in cells when freshly gathered, in spirits of wine
and water—one part of the former to six of the latter, and their
attachment to their stipes remains afterwards undisturbed, unless
violence be employed to separate them.

In preserving the Diatomacee in balsam, the siliceous valves
are the portions alone required. Indeed, it would be imprac-
ticable satisfactorily to mount specimens in their natural state

XXXll INTRODUCTION.

in such a medium, as the presence of the cell-contents would
prevent the access of the balsam to the interior of the frustule.
T'o procure the valves in a separated state, it is necessary to boil
the frustules for a few minutes in muriatic or nitric acid; thus
removing the softer parts, and dissolving the connexion between
the various portions of the frustule. The acid must afterwards
be removed by repeated washings, allowing the siliceous mate-
rials to settle to the bottom of the vessel after each addition of
water: we thus procure the specimens im a proper state.
Having poured off the superfluous water, a drop of the fluid
containing the Diatomacez is to be placed on the slide, evapo-
rated to dryness, and the balsam and cover applied as in the
ordinary mode. ‘To avoid the presence of air-bubbles, it is only
necessary to use the balsam in a sufficiently fluid state ; and this
may be secured by mixing it with ether or rectified spirits
of turpentine, taking care entirely to expel the latter by the
application of a gentle, but long-continued heat, before applying
the glass cover.

With some valves, more especially in those specimens the
resolution of whose cellular structure requires the application of
the highest powers of the instrument, a different mode of mount-
ing is necessary, as the application of balsam obliterates the more
delicate markings. Such objects must be preserved in a dry
state, without bemg immersed in any medium, and must not
only be covered with glass sufficiently thin to allow the approach
of a lens of high power, but also placed upon a glass slide,
whose thickness will not impede the use of condensing lenses
of short focal lengths. These objects are accomplished. by per-
forating a wooden or metallic slide, and placing upon the per-
forations, which ought to be as large as practicable, a portion of
thin glass, to receive the object, cementing this to the slide, and
placing over it a cover of glass not exceeding z}oth of an inch
in thickness, and thinner if possible. ‘To prevent the admission
of moisture, which would ultimately make its way to the object
and destroy its value, it is indispensable that the cover should
be cemented to the thin glass below. A neglect of this precau-
tion will, sooner or later, be followed by the loss, to all valuable
purpose, -of the contained specimens.

INTRODUCTION. XXXII

In noticing the usual habitats of the Diatomacee, I have
omitted to mention a locality not ordinarily accessible—the
deeper parts of the ocean—which can only be reached by the
dredge of the more enthusiastic and laborious collector. Many
teresting species will reward a search conducted with this
unplement. The magnificent Campylodiscus Horologium, P\. V1.
fig. 51, was thus obtamed. But these more hidden “ treasures
of the deep’ may be reached in an indirect mode, by employ-
ing those fishes or molluscs which frequent deep water, as our
substitutes for the dredge. Thus, in the stomachs of the crab
or lobster, sole or turbot, the scallop or whelk, such organisms
are often found; and several species, rarely or never occurring
im my usual haunts, have been supplied in abundance by a
careful dissection of the above microphagists.

I have also failed to indicate any season as more suitable
than another for the researches of the student. I have, how-
ever, designedly omitted to do so, as every season is productive
of interesting forms. The notes appended to the descriptions
of each species, in which I have, when possible, recorded the
months mm which the species were collected, will show how
perennial is the supply. Weather permitting, the collector may
always reckon upon well-filled bottles, provided his rambles are
by the sea-coast, or through a district supplied with ponds
and streams. I take my leave of him for the present, by
recommending to his pursuit a study pregnant with interest
and with beauty; which fills the mind with wonder in the con-
templation of forms at once so minute and perfect, so humble in
their individual capacity, and yet by their numbers and wide
diffusion occupying an important position in the organic world,
and fulfilling the purposes of Power, Wisdom, and Benignity.

ADDENDA ET CORRIGENDA.

Page 5, line 11, for studied, read stated.
7, line 9, for the genus Diadesmis substitute the genus Achnanthidium.

11, add to the instances of Conjugation in Epithemia, E. Zebra; noticed by Mr. Thwaites
in Ann. Nat. Hist., Nov. 1847. :

21, to the description of Cocconeis Placentula, add, Striz 45 in :001”; and to habitat,
In Conjugation, Lewes, Feb. 1853.

23, line 5, for Orthosira sulcata, Kitz., read Melosira sulcata, Kutz.

24, to the locality of Eupodiscus crassus, add, Stomach of scallop, Feb. 1853.

25, to the habitat of Eupodiscus sculptus, add, Isle of Dogs, Mr. Roper.

27, Triceratium striolatum? Ehr. Specimens from Mr. Brightwell have satisfied me
that this is not 7. striolatum of Ehrenberg; I therefore propose for it the name
of 7. undulatum.

29, to the localities of Campylodiscus spiralis, add, Newhaven, Sussex, Dec. 1852,
W. Sm.

33, Surirella panduriformis is probably a var. of S. pinnata.

35, for n. sp. annexed to T’ryblionella Scutellum, read W. Sm.

40, add to the habitat of Nitzschia angularis, Poole Bay, Sept. 1849, W. Sm.

51, last line but one, insert a full stop after 42, and read in continuation, Var. 8. Ehr.
Inf. xiii. 7, ef seg. ~

SYNOPSIS

THE BRITISH DIATOMACE A.

PRELIMINARY NOTICES.

Tue following List includes the principal works on the Diatomacez
which the writer has had the opportunity of consulting. The
prefixed abbreviations indicate the contractions employed when
reference is made to such works or their authors.

Ag. Syst. Systema Algarum. C. A. Agardh, 1824.
Ag. Consp. Conspectus Criticus Diatomacearum. C. A. Agardh, 1830.

Bail. Sound. Microscopic Examination of Soundings off Atlantic Coast of
the U.S. By Professor J. W. Bailey (in Smithsonian Contributions to
Knowledge), 1850.

Bail. Obs. Microscopical Observations in S. Carolina, Georgia and Florida.
By Prof. J. W. Bailey (in Smithsonian Contributions to Knowledge),
1850.

Bréb. Alg. Algues des Environs de Falaise, par MM. De Brébisson et Godey
(Mémoires de la Société Académique de Falaise), 1835.

Bréb. Consid. Considérations sur les Diatomées, par A. De Brébisson.
Falaise, 1838.

Bright. Inf. Sketch of a Fauna Infusoria for East Norfolk. By T. Bright-
well, F.L.S., 1848.

Dick. Ann. Papers in the Annals of Natural History. By Professor
Dickie, v. d.

Dillw. Conf. British Confervee. By L. W. Dillwyn, F.R.S. & F.L.S., 1809.
Duar. Inf. Ynfusoires, par F. Dujardin, 1841.
Ehr. Inf. Die Infusionsthierchen, von D. C. G. Ehrenberg, 1838.

Grev. S.C. F. Scottish Cryptogamic Flora. By R. K. Greville, LL.D.
6 vols., v. d.

Grev. B. F. The Diatomacee in Hooker’s British Flora, vol. 1. P. 1. p. 401
et seg. By Dr. Greville, 1833.

Harv. Man. Manual of the British Algee. By W. H. Harvey, M.D., 1841.

Hass. Alg. Wistory of the British Freshwater Algze. By A. H. Hassall,
F.L.S. 2 vols., 1845.
B 2

4 PRELIMINARY NOTICES.

Jenn. F. Tun. Flora of Tunbridge Wells. By E. Jenner, A.L.S. (no date).
Kitz. Bacill. Die Kieselschaligen Bacillarien, von F. T. Kiitzmg, 1844.
Kitz. Phy. Ger. Phycologia Germanica, von F. T. Kiitzing, 1845.

Kitz. Sp. Alg. Species Algarum, von F. T. Kiitzing, 1849.

Lyng. Tent. Tentamen Hydrophytologiz Danice. H.C. Lyngbye. 2 vols.,

1819.

Prit. Anim. A History of Infusorial Animalcules. By A. Pritchard, M.R.I.,
1852.

Quek. H. C. Histological Catalogue of the College of Surgeons. By
J. Quekett.

Ralfs, Ann. Papers in the Annals of Natural History. By J. Ralfs,
M.R.C.S., v. d.

W. Sm. dnn. Papers in ditto. By Rev. W. Smith, F.L.S., v. d.
Thw. Ann. Papers in ditto. By G. H. K. Thwaites, v. d.

The letters n. sp. denote that the species to which they are appended is
believed to be now for the first time described: W. Sm. that the species has
been previously described, or the generic or specific name been altered, by the
present writer ; in the latter case the original appellation is given in the list of
synonyms. In other cases the writers by whom generic and specific names
have been first employed are indicated by contractions, the signification of
which may generally be ascertained by a reference to the list of authors
given above.

The following abbreviations are adopted in the text :—

F.=Frustule.
F. V.=Front view of frustule.
S. V.=Side view of frustule.
V.= Valve.

1''= English inch.

The letters S. V. and V. may usually be employed indifferently, as in most
cases the outline of one valve, when its general surface is turned towards the
observer, is identical with that of the side view of the entire frustule.

The letters v.v. following the specific description imply that I have examined
a living specimen, and v.s. that I have seen the species only in a dry or
fossil state.

The letters which accompany the numbers in the Plates indicate that the
figures to which they are attached represent,—a, a side view; 6, a front
view ; ¢, a front view of single valve; and d, self-division: when a numeral
alone is employed, the figure is that of a side view of a single valve.

The unit of measurement employed is that of an English inch, the magni-
tudes being expressed in decimals, thus enabling those who may desire to
reduce the dimensions given to the various continental standards (when the
values of these are known), to do so by a simple process. The scale in each

PRELIMINARY NOTICES. 5

plate affords a ready means of ascertaining the size of the specimen from
which each figure has been drawn ; but where much diversity has been found
to exist in the dimensions of the individuals examined, the extremes observed
have been noted in the text.

The figures, unless when otherwise indicated on the Plates themselves, are
to be regarded as representations of the objects as seen under an amplifying
power of 400 diameters, and the details given may be taken as tests of the
defining capability of an instrument provided with a magnifying power of
that amount. Ina few cases a lens of somewhat higher power has been
employed, to resolve and estimate the number of the strize, this designation
being applied in every case, not otherwise studied, to the transverse lines or
markings of the siliceous valves.

The following British Diatomaceous deposits, recent or subfossil, are those
most frequently referred to :—

PETERHEAD Deposit. Described in the Annals of Natural History, Aug. 1848,
by Professor Dickie.

Premnay Prat. Described in the Annals of Natural History, Aug. 1848,
by Professor Dickie.

Doucetty Eartru. Supplied by Chr. Johnson, Esq., Lancaster, 1850.
Noticed by him in the Annals of Natural History, June 1847.

Mart, Co. Down. Supplied by J. M°Adam, Esq., Belfast, 1849.

Loveu Istann-Reavey Depostr. Supplied by the late William Thompson,
Esq., Belfast. Described in Magazine of Natural History for J uly 1839,
by Dr. Drummond; and noticed in the Annals of Natural History, Feb.
1850, by the present writer.

Lovey Mourne Depostr. Described in Annals of Natural History, Feb.
1850, by the present writer.

Cantyre Prat. Supplied by Prof. Balfour, and noticed in the Annals of
Natural History, April 1851 and June 1851.

Raasay Eartu. Fossil Earth from the Island of Raasay, supplied by Prof.
Dickie.

A few species are referred to Foreign localities ; these references have been
determined by specimens distributed by the London Opticians or known to
microscopical observers, and for the genuineness of which the present writer
is unable to assign his personal authority ;—such notices may serve in some
degree to indicate the wide range of many of our native forms.

SYNOPTICAL ARRANGEMENT

OF THE

BRITISH DIATOMACEZ

Crass CRYPTOGAMIA.

Sup-cuass ALGA. Naturau Orpvper DIATOMACE.

Plant a FrusTuLe ; consisting of a unilocular or imperfectly septate celf
invested with a bivalve siliceous epidermis. GEMMIPAROUS INCREASE, by
Sevr-Division ; during which process the cell secretes a more or less siliceous
ConneEcTING MEMBRANE. ReEpRODUCTION, by ConsuGaTion and the
formation of Sporangia.

Trise L. Frustules naked ; not imbedded in gelatine nor enclosed in mem-
branaceous tubes.

Sus-TRIBE 1. Connecting membrane deciduous; frustules solitary or
during self-division in pairs, rarely in greater numbers,
adherent or free, dispersed, or aggregated into a mucous
stratum.

22 Genera. Epithemia, Eunotia, Cymbella, Amphora, Cocconeis,
Coscinodiscus, Eupodiscus, Actinocyclus, Arachnoi-
discus, Triceratium, Cyclotella, Campylodiscus,
Surirella, Tryblionella, Cymatopleura, Nitzschia,
Amphiprora, Amphipleura, Navicula, Pinnularia,
Stauroneis, Pleurosigma.

SYNOPTICAL ARRANGEMENT. 7

Sus-Tr1BE 2. Connecting membrane subpersistent ; frustules after self-
division attached by a gelatinous cushion, or dichoto-
mous stipes.

7 Genera. Synedra, Doryphora, Cocconema, Gomphonema, Po-
dosphenia, Rhipidophora, Licmophora.

Sus-TRIBE 3. Connecting membrane evanescent, or obsolete ; Srustules
after self-division united into a compressed filament.

12 Genera. Meridion, Bacillaria, Himantidium, Odontidium, Den-
ticula, Fragilaria, Eucampia, Achnanthes, Diades-
mis, Rhabdonema, Striatella, Tetracyclus.

Sus-TRiBE 4. Connecting membrane subpersistent ; frustules after self-
division united into a zigzag chain.

6 Genera. Diatoma, Grammatophora, Tabellaria, Amphitetras,
Biddulphia, Isthmia.

Sus-TrIBE 5. Connecting membrane subpersistent as a siliceous annulus ;
frustules after self-division united into a cylindrical
filament.

3 Genera. Podosira, Melosira, Orthosira.

Trise II. Frustules invested with a gelatinous or membranaceous envelope.
Sus-rriBe 6. Frond indefinite, mammillate ; frustules scattered.
| Genus. Mastogloia.
Sus-TriBe 7. Frond definite, compressed or globular ; Srustules scattered.
2 Genera. Dickieia, Berkeleyia.
Sus-TR1BE 8. Frond definite, filamentous 3 frustules in rows.
3 GeneRA. Encyonema, Colletonema, Schizonema.

Sus-rriBE 9. Frond definite, filamentous ; frustules fasciculated.

1 Genus. Homeeocladia.

ANALYSIS OF THE GENERA.

1. Frustules nude ........... By
bs enveloped in ean c or » enclosed ; im laglemeeeras Be 46
2. Frustoles not forming *a filament’... 22. 2+ ci- ae eee 3
- forming a filament, ore win <7 2 4 ers -11-y- idee ee 28
dese rustules freeior ‘adherent? ie 2. 8 oe eee eee Same 4
ft attached by a ‘cushion or, stipes *........2.5--- 7 ees
4. Frustules furnished with canaliculi ......................---- 5
es not iso farmished. ,5...0 25, yk a ee ee 7
5. Valves arcuate or inflated 2... 0.2.....0c2 Jon. coe ces UPD DEaenmee

a

10.

1

12.

13.

14.

», _ Saddleshaped \i.000.4). 022 ich sonaee sees. \CAMPYLOMIS@uR
a5) elliptical; ‘ovate or linear, (6.1 ese a ee ee 6

. Valves concave, alee marginal .... 20...) 2... 2): 2 OUR Eee

»» _ plane, ‘alesubmargimal ...0. 02. U.2204-..- ER YVBETONREse

. Valves triangular...) Jonnie ate eye eeaheteeyetei os tye 2a et BCE
33 sOrbicular® y. cree Te ee SP eo & 8
» not triangular nor caylee a favs.oneaey ehetrencwo oie de Se
sav alyesisirlated! ss \cc seine ne sia tt lyohietee Rites RM Os ia. HOC One IEam
soie @ COLLAR Sra ors orn chaste crm aetna ee As, 9
BEG Urs aoe baRAa sea oce ieueielalegeiet sea ore heed
Bp pe L6G ALES 721) Br a Meee A RAG pe ie AAR OE red oda ape ACTINOCYCLUS.

Discs of Valves furnished with processes.............. Evpopiscus.
re 5 not ‘so furnished. i. 555% 2.2. oe ee

Valves with a central pseudo-nodule Bor ARACHNOIDISCUS.
»» without a central nodule.................. Coscrnoptscus.

Valves arcuate. ... a sesiss otaaiane. AUONOTEEE
as 8 WMOLARCUALE Brey ewer ties ckeon es a Site eee. 1G
Valves cymbiform. . FO aE ee a asus ees Ud!
» elliptical, alla or “Tai. SOAS, 85 5.0 oF SoGe ae oe ee

Nodule subcentral silos SRE Dees COM SED Ris tar
43° e Mmargmal: 27h. seievckaseeee Shon he eo EEE Bae

15.

16.

Gis

18.

19.

20.

21.

22

23.

. Valves having terminal and subcentral nodules

ANALYSIS OF THE GENERA. 9

Brustulesiadherent.. 2. ....5.0... Scticicis na sc Spoveyei tres 212 tC OCCONEIS.
a RCC acs ct esis, cio? oi Societe Meh stare aiotal eke ice Rie ete tearcis ore 16
Valves transversely undulated .......... BO ora ont CYMATOPLEURA.
eb sOWILMOUL UNGULATIONS: :...: 525m sa sss eee areetererts 2. NS
Valves with longitudinal ridges .............- KAtaiuecind oui. 18
Riie PLANE OT CONVEX...) everson er teen rel «m0 reine eiaten 20
Walyes witht atcentralimdce or Keeliiire.< 1. co oo = scl tereareral- 19

»5 with two or more ridges ...:.............. AMPHIPLEURA.

Valves elliptical, deeply constricted .............. 0. AMPHIPRORA.
», much elongated ; constriction, if any, slight ...... Nirzscura.
Walves siomordinns scsi Sete set ois cits HOS ees ace RU ROSIG NAL

Sy SURG geter toy a esucna oso) ore, Apeccte hate 5 Sake ie DRS a ata he ey 124
Wakes Satin @amadail moll 255 6550 cocno0 noodsasg0ce sons 72
» with central nodule dilated into a Stauros ...... STAURONEIS.
Valveshstriated sci s eg the. s auteur ey eyaicne arr ae ekore NAVICULA.
BME COSUALCU 2i2)s,0 Aa coctoine cicke sioner sions Sate a eee PINNULARIA.
Frustule linear or much elongated .................... SYNEDRA.

3 ellipticaloricymbitonm ys. 22 ee heats eer nts oe 24
5 CUNEATE Ae sero e e nas et soni Se ctaiee Dinan Pilar ee

ey aor Ys CoccoNEMA.
+) without nodules). 0/55. 0202 2c. oe. DORYPHORA,

25. Valves with a nodule in the centre and at each end.... GoMPHONEMA.
Peae OW it OMEN O CULES race nee Sty) SACGED crea ccemaes OPN os Ara era ae 26
ZGeesupesionsoleteyor, very, SHOt= 1. hacjas 4-00 cise oo ee PopOSPHENIA.
siap KE LOMR AEM sy ee era ror clal ela kits tas WAtee Staten meee ed
fem SuUDeS) LUM OTIN) = -tneites) 6 = 2) ele =1]s.ai4 = ve'e s!eieie) ciat= <eeloiets RuIPIDOPHORA.

28.

30.

31.

32.

MAMANCTASSALC Parte tele a Hee eau tc delorsic ics ie ele. LAL CMO PHO Rate

Milamentcompressed, contmuoust).. 45-0 5 ey Pacers eee iO,

Ae ZS 7Aes CLAN pri ae sone stele athasotes sees eiewee. at oy olay wisi OD
‘. Gylindrical 8. yes sanct 5 ye ose ce eee einte a lofetet eaten 44
me Pulament spirale ...c7a a). erste eyes acc s + oes NEBR EDIONG
ie COU are ee ee es eet BACILLARIA.
Ps Strate Gvvepeye te por eicie el ete icici eerselehate tc ee eee 30

Erustulecwithyimternal septa. giana a5 cis: oc ore + re epi
5 WItHOULESED beers, 1 a)staye <i'4 cus ote ies) aleertions cle eee 31

Valves with central and terminal nodules .............. D1AprEsmis.
» without nodules.:.... Sn re ee a eRe ee na OD

Frustule curved on Front View.................... ACHNANTHES.
pee LOD Onedony ErOntaViewWa cc ce «sector teeter tty lier: mers 33

10

ANALYSIS OF THE GENERA.

SaneVAlWES AFCUALE.'. cit) eee Sch, ee .... HIMANTIDIUM.
ap) < BITMISDL © Go". 2 ent Se eee ee 34

34, ; Valves with ia'central smus .)......4.e.40aca. lo eee Eucampta.
» without a sinus.... oF e's 2 eg nbele) ateabyeheyay el s:'eiS «1 s/uncee eine ae

3d. Valves delicately striated ....:. ..0e.c05 ne bans eek. FRAGILARIA.
3 adistinethy costate <..>.- 42a ee ee «oti ee

36. Frustules united into a lengthened filament .......... OponTIDIUM.
* few, scarcely forming a filament .......... -- DENTICULA.

37- Erustules/compressed, =... . 0... -2.-9-. 4. see she! eisie fale eee 38
- mflated os ee he beineccaeeee ce sees nae

35.) tilamentitenacioussry--4. 2. ee ee ee Sales rere RHABDONEMA.
AA not tenacious........ steso apa note Ure ape eee STRIATELLA.

39. Frustules with internal septa .......... 0: sis\ais wits: os See 40
os without Septa 2. scott. 00 mines > cane ce «ow een

BO: WSentes Waves 7k sr ctarnc wae Mey ie eee ee GRAMMATOPHORA.
gay os SUPA ye iy ea kero eRe, ee ee TABELLARIA.

41. Frustules square or rhomboidal.................... AMPHITETRAS.
“ compressedie. ae eee a seis eke iev'eseis ss oe 42

f2-) Brustules) prismatic ee, ice inet eae nee ae eee Diatoma.
a6 Subeylindrical yl .28 2° 2 ia-cateee eee 43

43. Angles of frustules rounded, slightly produced ............ IstHMIA.
Se Ch yproduceda ls er eee Sty acre eae BippULpHIA.

A4- Hilament (of few dtrustules'95.. .2 5/02) ei. snes PopostrRa.

45.

46.

48.

49.

50.

a mumerous frustules £2. ....2..... 0) oe ee

Frustules with rounded extremities................ .... MELOSIRA.
55 truncated 7.2.80 eee en OrTHOSIRA.

Prond indefinite: e022 wer) eee eee ee MAstToGuora.
Sp RMMLCHDILOH IAS tes, Sica, Ons. ik ben cee Nl ct Oe 47

se Hrondycompressed ee sey en ie eee any ee pen ee DicktieEIA.

a) lobular. Be eee cre: Ask eeags oe) IDET
ay. © Wilamentous. 17... e sk ee ee eee 48

Brustules in rows) aks ee ot kee a ee 49
is fasciculated |. : 04)... 2 sees elec ecee dds ELOMC@OCiiae
Frustules those of a\@ymbella.......:.....0022255 oh ENCYONEMA.
ys Ps Navieula. o's 55%. c<lc4inc te Coe eee ee 50
Filaments simple axe: Ae ne ee eee CoLLETONEMA.

* branched.) -ceesucor eee a ee es.. SCHIZONEMA.

THE BRITISH DIATOMACE#.

Genus 1. EPITHEMIA, Aiitz.

Frustules adherent, quadrilateral ; valves arcuate, furnished with trans-
verse canaliculi.

A section of the frustule in the present genus would present an
outline of varied form, either elliptical or quadrilateral, or that of two
nearly perfect circles united by an oblong isthmus; the shape of the
frustule in the latter case may be compared, as it has been done by
Meneghini, to that of a coffee berry, or more correctly to a grain of
wheat, but in no case would the section present a trapezoidal outline,
the valves being always parallel or equidistant. This genus, as the
name implies, is characterized by the adherence of its frustules to
Algze of a larger growth. This character is true of most of the species,
and even where not strictly applicable, as in E. gibba and others, we
detect a disposition to rely on a foreign body for support, their
frustules being usually imbedded in the mucus of some member of
the family of the Palmeilacez.

The transverse costa, so conspicuous in some species, I regard
as minute canals, which convey the nutrimental fluid to the surface
of the internal membrane. They are not modifications of the cellular
structure of the siliceous epiderm, otherwise, the striz would not
pass, as they do, uninterruptedly over the entire surface of the valve.

Conjugation, and the formation of Sporangia in this genus, have
been noticed by Mr. Thwaites in E. turgida and E. gibba, by myself
in these species and in E. Sorex.

ie, BRITISH DIATOMACE.

1. Epithemia Hyndmanii, JV. Sm. F. V. inflated; V. much and
regularly arched, extremities rounded, not recurved; striz moni-
liform, 16 in 001”; canaliculi inconspicuous, 9 in 001". Length
of F. °0025" to -0076". v.s.

W. Sm. Ann. 2nd Ser. vol. v. p. 124.

Fresh water. Lough Mourne Deposit, Cantyre Peat.
iPlatesat':

2. Epithemia turgida, /V. Sm. F.V.somewhat inflated ; V. slightly
arched, extremities suddenly attenuate, obtuse ; striz moniliform,
21 in :001"; canaliculi distinct, 12 in 001". Length -0026" to
0062". v.v.

Epithemia Vertagus, Kitz. Bacill. xxx. 5. sic. cl. De Brébisson in litt. cum
specim.

Eunotia turgida, Ebr. Inf. tab. xiv. 5. xxi. 20a. Quek. H. C. xu. 5. In
Conjugation, Thw. Ann. vol. xx. pl. iv. Prit. Anim. xiv. 1-8.

Cymbella turgida, Hass. Alg. pl. ec. 7.

Fresh water. Near Aberdeen, Dr. Dickie. Wareham, Lewes, May 1850,
&e., W. Sm. Lough Mourne Deposit, Dolgelly Earth, Cantyre Peat and
Peterhead Deposit.

Plate I. 2. Frustule with endochrome, Frontispiece, vol. i. fig. IT.

3. Epithemia granulata, Kitz. F.V. linear; V. slightly arched,
linear, otherwise like the last. Length :0033” to 0081". v.s.

Kitz. Bacill. v. 20. Hunotia granulata, Ehr. Inf. xxi. 20 p.
Fresh water. Lough Mourne Deposit.
Plate I. 3.

4, Epithemia Zebra, Kiitz. V. equally arched; F.V. linear; ex-
tremities of V. gradually attenuate; stria punctate, 33 in 001";
canaliculi few, 8 in 001". Length :0016" to 0035". v.v.

Kitz. Bacill. v. 12. Hunotia Zebra, Ehr. Inf. xxi. 19. Cymbella Zebra,

Hass. Alg. c. 8.
Fresh water. Wareham, Lewes, &c., Aug. 1850, W. Sm.

Plate I. 4.

5, Epithemia Argus, WV. Sm. fF. resembling the last; foramina
conspicuous on the F. V. Length :0013” to‘0021". v.v.
Epithemia alpestris, Kitz. Sp. Alg. p. 2. ad spec. authent. que misit cl, De
Brébisson, Jan. 1853. Prit. Anim. xxiv. 11.
Fresh water. Near Aberdeen, Dr. Dickie.
Plate I. 5.

BRITISH DIATOMACE&. 13

6. Epithemia ocellata, Kitz. F. V. inflated, extremities of V.
rounded, foramina large. v.s.

Kitz. Bacill. xxix. 57.
Fresh water. Wray near Lancaster, Mr. G. Smith. Cantyre Peat.
Plate I. 6.

7. Epithemia longicornis, Ehr. F. V. inflated, extremities obtuse ;
dorsal ridge of V. somewhat angular; foramina few, large; striz
27 in :001". Length -0033" to :0058". v.v.

Ehr. in Prit. Anim. xxiv. 6-9.

Fresh water. Isle of Arran, mixed with Petalonema alatum, Berk. col-
lected by Professor Walker Arnott, Aug. 1852.

Supp. Plate XXX. 247.

8. Epithemia alpestris, /V. Sm. F. V. linear; V. recurved at the
obtuse extremities ; foramina large; striz 27 in ‘001". v.s.

Kiitz. Bacill. v. 16?
Fresh water. Katefield near Lancaster, Mr. G. Smith, April 1851.
Plate I. 7.

9. Epithemia proboscidea, Kiitz. FF. V. inflated; V. recurved at
the extremities; canaliculi large; foramina inconspicuous ; strize
20nmi-OOL > wiv.

Kitz. Bacill. v. 13.

Fresh or brackish water. St. Ouen’s Pond, Jersey, Aug. 1852, W. Sm.
Raasay Earth.

Plate I. 8.

10. Epithemia Sorex, Kiitz. F.V. inflated; V. attenuate, slightly
recurved at the extremities, dorsal line highly arcuate ; canaliculi
few, minute; striz 33 in ‘001". Length :0009" to 0013". v.v.

Kiitz. Bacill. v. 12.

Fresh or brackish water. Lewes, May 1850, W. Sm. Lough Mourne
Deposit, Cantyre Peat, &c. (New Zealand.)

Plate I. 9. Frustule with endochrome, Frontispiece, vol. i. fig. IX.

14 BRITISH DIATOMACE.

11. Epithemia Musculus, Wiitz. V. regularly and highly arcuate,
extremities acute; canaliculi distant; strize 40 in -001". v.v.

Kiitz. Bacill. xxx. 6.

Brackish water. Poole Bay. “ Little Sea,” Dorsetshire, Aug. 1848. Near
Lewes, Sussex, Sept. 1850, W. Sm.

Plate I. 10.

12. Epithemia Westermanii, Kiitz. FF. V. elliptical; V. arcuate ;
canaliculi distinct; striz faint, 40 in :001". Length -0008" to
SOO SS OiveNs

Kitz. Bacill. v.12? Eunotia Westermanii, Ehr. Inf. p. 190. taf. xiv. 6?
Brackish water. Near Lewes, Oct. 1850, W. Sm. (Ceylon, Mr. Thwaites,
Nov. 1851.)
Plate Ts U0.

13. Epithemia rupestris, n.sp._ F. V. elliptical-lanceolate; V.
acute, slightly arcuate; canaliculi distant, 6 in ‘001" ; striz faint,
42 in 001". Length 0012" to :0023". v.v.

Fresh water. Backsbottom near Lancaster, Mr. G. Smith, April 1851.
Plumpton, Sussex, April 1852, W. Sm. Aberdeenshire, Dr. Dickie. Killi-
crankie, Mr. P. Grant. Raasay Earth.

Plate I. 12.

The above species first fell under my notice in a gathering made by Mr. G.
Smith from the surface of a rock moistened with water in the habitat I have
mentioned ; its frequent occurrence in other localities shows that it is widely
distributed in subalpine districts. Together with the species last described,
and the three which follow, its valves present a peculiar form : their convexity
is so considerable, that a transverse section of the frustule would furnish an
outline not unlike the figure 8, owing to which circumstance a side view is with
difficulty obtained, the frustules naturally presenting their broadest surface to
the eye.

14. Epithemia constricta, n. sp. F. V. elliptical with a more or
less distinct constriction ; V. acute, much arched ; canaliculi distant,
8 in 001"; striz 30 in :001". Length :0012" to 0026". v.v.

bb)

“Ep. constricta,
Brackish water. Excet, Sussex, March 1852, WV. Sm.
Supp. Plate XXX. 248.

cl. De Brébisson in litt. eum specim.

BRITISH DIATOMACE. 15

15. Epithemia gibba, [iitz. IF. V. linear, slightly inflated at centre
and extremities ; S. V. linear, obtuse; striz 36 in ‘001"; canaliculi
15 in ‘001". Length :0033" to -0104". _ v.v.

Nav. gibba, Ehr. Inf. xiii. 19. Hass. Alg. cii. 4.

Ep. gibba, Kitz. Bacill. iv. 22.

Eunotia gibba, Prit. Anim. xv. 27. In Conjugation, Thw. Ann. vol. xx.
pl xxu. Fi.

Fresh water: frequently entangled in the mucus of Sorospora virescens,
Hass. Wareham, Aug. 1847. Lewes, Oct. 1850, W. Sm. Lough Mourne
Deposit. Peterhead ditto. Near Aberdeen, Dr. Dickie. Rescobie, Mr. P.
Grant. (San Fiore, Italy ; Ceylon, 1851, Mr. Thwaites.)

Plate I. 13.

16. Epithemia ventricosa, Kiitz. F. V. elliptical, slightly con-
stricted at the ends; V. with acute extremities ; striae and cana-
liculi as in the last. Length :0009" to :0018". v.v.

Kiitz. Bacill. xxx. 9. Nav. gibba, Ehr. Inf. taf. xii. fig. xix. 4.

Fresh or brackish water. ‘ Brooks” near Lewes, Oct. 1850. St. Ouen’s
Pond, Jersey, Aug. 1852, W. Sm. Near Aberdeen and near Belfast, Dr.
Dickie. Peterhead Deposit.

Plate I. 14.

Genus 2. EUNOTIA, Lhr.

Frustules free, oblong; valves arcuate, with terminal nodules and
convergent striz.

Closely allied to the former genus, but easily distinguished by the
absence of canaliculi, the delicacy of the strize and the dorsal ridges
with which most of the species are provided. The F. V. is also uni-
formly linear, and the connecting membrane less fully developed than
in many of the Epithemia. Isolated frustules of Himantidium might
be confounded with the present species, but Ewnotia never forms a
tenacious filament, though several frustules may sometimes be found
united ; the genera are however closely allied, and with difficulty
distinguished from each other.

1. Eunotia Arcus, W.Sm. V. regularly arcuate, acute, with a
slight constriction at each extremity, and inflation in the centre of

16 BRITISH DIATOMACE.

the concave margin; strie delicate, 36 in 001". Length :0012”
to 0029". v.v.

Navicula Arcus, Ehr. Inf. xxi. 10. Cymbella? Arcus, Hass. Alg.c. 6. Ce-
ratoneis Arcus, Kiitz. Bacill. vi. 10.

Fresh water. In boggy pools, Dorsetshire, Jan. 1849, W. Sm. Wray
near Lancaster, Jan. 1852, Mr. Geo. Smith. Mountains in Forfarshire, Dr.
Dickie.

Plate II. 15. Frustules with endochrome, Frontispiece, v. i. fig. XV.

2. Eunotia gracilis, n.sp. V. arcuate, extremities recurved ; striz
delicate, 42 in ‘001". Length 0006" to :0018". v.v.

Fresh water. Wareham, Sept. 1849, W.Sm. Jack’s Wood Spring, Tun-
bridge Wells, Mr. £. Jenner.

Supp. Plate XXX. 249.

3. Eunotia monodon, Hhr. V. regularly arcuate, obtuse, extre-
mities slightly produced; striz 34 in ‘001". v.s.

Ralfs, Ann. vol. xii. pl. xiv. 1.

Fresh water. Ben M° Dhui, at an elevation of 3000 feet, Mr. P. Grant.
Aberdeenshire, Dr. Dickie.

Plate II. 16.

4, Eunotia diodon, Ehr. V. with two dorsal ridges; striz 32 in
OO!) 2 evs.

Ehr. Inf. xxi. 23. Ralfs, Ann. vol. xiii. pl. xiv. 2. Hass. Alg. xevi. 6.
Kutz. Bacill. v. 24.

Fresh water. Aberdeenshire, Dr. Dickie. Ben M° Dhui, Mr. P. Grant.
Plate II. 17.

5. Eunotia triodon, Hhr. V. with three dorsal ridges; strix
40 in :001". Length :0015" to 0026". v.s.

Ehr. Inf. xxi. 24. Prit. Anim. iii. 164. Hass. Alg. xevi. 7. Kiitz. Bacill.
Vin PAD

Fresh water. Ben M* Dhui, at an elevation of 3000 feet, Mr. P. Grant.
(Lapland. )

Plate II. 18.
6. Eunotia tetraodon, Ehr. V. with four dorsal ridges; striz
24 in 001". Length :0015" to :0022". v.v.

Ehr. Inf. xxi. 25. Ralfs, Ann. vol. xiii. pl. xiv. 4. Hass. Alg. xevi. 8.
Kitz. Bacill. v. 26.

BRITISH DIATOMACE&. 17

Himantidium tetraodon, Bréb. in Kitz. Sp. Alg. p. 10. ad spec. quee misit
amic. De Brébisson, Jan. 1853.

Fresh water. Ashdown Forest, Sussex, Aug. 1850, W. Sm. Curwen
Hill, Lancashire, Mr. G. Smith, June 1851. Quernmore, Lancashire, April
1852, Mr. Johnson. Mountains in Aberdeenshire, Dr. Dickie. Dolgelly,
Mr. Ralfs. Dolgelly Earth. Peterhead Deposit. (Manchester, Mass., com-
municated by Prof. Williamson.)

Plate II. 19.

7. Eunotia Diadema, Hir. V. with six dorsal ridges; stria 30 in
001". Length 0016" to -0024". v.s.

Ehr. Inf. xxi. 27. Kiitz. Bacill. v. 28.
Fresh water. Dolgelly Earth.
Plate II. 20.

Genus 3. CYMBELLA, 4y.

Frustules free, cymbiform ; valves striated, with a submedian line and
central and terminal nodules.

Many frustules of Cocconemata detached from their stipes bear so
close a resemblance to those of the Cymbelle, that a discrimination
can hardly be relied upon which depends solely upon the observation
of prepared specimens. In a living state, the presence of a stipes at
once removes such frustules from the present genus. Cymbella fre-
quently forms a more or less distinct stratum, the frustules being re-
tained in their position, even when exposed to a rapid current, by the
presence of a delicate pellicle of mucus.

1. Cymbella Ehrenbergii, Kiitz. V. elliptical-lanceolate, extre-
mities slightly produced, obtuse; striz distinct, 15 in <OOM:
Length :0028" to 0054". v.s.

Kiitz. Bacill. vi. 11. Navicula inequalis, Ehy. Onf. xiii. 18. Prit. Anim. 11.
154.

Fresh water. Living, in Lough Mourne, Sept. 1849. Peterhead Deposit.
Lough Mourne Deposit. Premnay Peat. Marl, Co. Down. (Near Manchester,
Mass., communicated by Prof. Williamson. Very abundant in fossil earth,
San Fiore, Italy.)

Plate II. 21.

18 BRITISH DIATOMACEA.

2. Cymbella cuspidata, Kiitz. F. smaller than the last, extremities
prominent, somewhat acuminate ; striz indistinctly moniliform,
30 in :001". Length -0012" to 0031". v.s.

Kitz. Bacill. i. 40.

Fresh water. Quernmore near Lancaster, April 1852, Mr. Johnson. Wray
near Lancaster, Oct. 1852, Mr. G. Smith. Lough Mourne and Peterhead
Deposits. Premnay and Cantyre Peats. (Nova Scotia.)

Plate 22:

3. Cymbella affinis, Kiitz. V. elliptical-lanceolate, extremities
slightly produced; striz faint, 30 in :001". Length -0009" to
‘OO1b" 5) vive

Kiitz. Bacill. vi. 15. ad spec. authen. quee dedit amic. De Brébisson.

Fresh water. Parham, Sussex, Feb. 1844, Mr. Jenner. Tford, Sussex,
April 1852, W. Sm. Marl, Co. Down, and Dolgelly Earth.

Supp. Plate XXX. 250. Frustule with endochrome, Frontispiece, fig. CCL.

4, Cymbella maculata, Kiitz. Larger segment of V. convex, smaller
with a slight inflation in the centre, extremities obtuse ; striz 27 in
7001". Length :0008" to :0015". v.v.

Kiitz. Bacill. vi. 2?

Fresh water. River Frome near Wareham, Dorset, March 1848, W. Sm.
Cantyre Peat and Peterhead Deposits.

Plate II. 23.

5. Cymbella Helvetica, Kitz. F. V. linear, slightly arched; V.
elongated, segments as in the last, extremities acute; striz 24 in
001". Length °0016” to :0031". v.v.

Kitz. Bacill. vi. 13? Prit. Anim. xvii. 24-28.

Fresh water. River Ouse near Lewes, W. Sm. Peterhead Deposit. Near
Aberdeen, Dr. Dickie.

Plate II. 24.

6. Cymbella Scotica, n.sp. V. narrow, elongated, smaller segment
straight, extremities acute ; striz 32 in ‘001". Length 0012" to
0027/0. aves
Fresh water. Pass of Killiecrankie, very plentiful, M7. P. Grant. Dolgelly

Earth.

Plated 25.

BRITISH DIATOMACE. iS,

Genus 4. AMPHORA, Fir.

Frustules free, or adherent ; valves cymbiform, with a central marginal
nodule.

The valves in this genus are exceedingly convex, closely resembling
those of Epithemia rupestris, and the section of the frustule is the
same as that which I have described under that species. It is pro-
bable that most of the Amphore are at first adherent, but they are
usually found detached, and sparingly diffused among other Algze.

1, Amphora ovalis, Kiitz. F. V. elliptical, internal margin of V.
inflated at the nodule; striz moniliform, distinct, 24 in ‘001".
Length :0012" to :0038". v.v.

Kiitz. Bacill. v. 25 & 39. Nav. Amphora, Ehr. Inf. xiv. 3. Prit. Anim.
tipo.

Fresh water: frequent. Lewes, April 1852, W. Sm. Lough Mourne De-
posit. Peterhead Deposit, &c.

Plate II. 26. Frustule with endochrome, Frontispiece fig. XXVI.

2, Amphora affinis, Kiitz. F. V. oblong, with round or truncate
extremities ; strie distinct, 27 in ‘001’. Length -0016" to °0022".
v.v.

Kiitz. Bacill. xxx. 66.

Brackish water. Near Lewes, Sussex, Feb. 1852, W. Sm.
Plate ITI. 27.

3. Amphora hyalina, Kitz. F.V. elliptical, acute; V. imperfectly
siliceous, longitudinally rugose; striz obscure. Length -0021"
to 0032". v.v.

Kutz. Bacill. xxx. 18.

Brackish water. Coast of Sussex, Nov. 1850, VW. Sm. Near Lancaster,
Mr. Johnson.

Plate ITI. 28.

4, Amphora salina, n.sp. F. V. elliptical, truncate, extremities
C2

20 BRITISH DIATOMACE.

slightly produced ; V. scarcely siliceous; strize 64in ‘001". Length
0008" to :0016". v.v.

Brackish water. I=ford, Sussex, Sept. 1852, W. Sm.
Supp. Plate XXX. 251.

5. Amphora? tenera, WV. Sm. F. V. oblong, extremities round or
truncate; V. scarcely siliceous, longitudinally rugose; striz 62 in
7001". Length :0015" to 0025". v.v.

Amphora lineolata, Kiitz. Bacill. v. 36. ad specim. authen. quae communicavit
cl. De Brébisson.

Marine. Formsathin pellicle on stones, &e. Seaford, May 1850. Lancing,
Nov. 1852, W. Sm.

Supp. Plate XXX. fig. 252.

6. Amphora membranacea, n. sp. F. V. elliptical, with rounded
extremities; V. scarcely siliceous, with a central transverse band ;
striz very faint, 80 in:001". Length :0013" to :0030". _ v.v.

Brackish water. Poole Bay, Sept. 1848. Sussex, Sept. 1850, W. Sm.
Near Belfast, Dr. Dickie. Near Harwich, Mr. Brightwell.

Plate IJ. 29.

7. Amphora? costata, n.sp. V. longitudinally costate, costze marked
with a double line of moniliform puncta; extremities produced.
Length -0020" to :0027". v.s.

Marine. Poole Bay, Sept. 1851, W. Sm.
Supp. Plate XXX. 253.

8. Amphora minutissima, n.sp._F. V. elliptical or oval; V. marked
with a transverse band ; striz 64 in ‘001". vv. :

Fresh water. Parasitic on Nitzschia sigmoidea. Near Lewes, Dec. 1850 and

Oct. 1852, W. Sm. In ponds near London, parasitic on Nitzschia linearis,
Mr. Shadbolt, Mar. 1851.

Plate II. 30.

BRITISH DIATOMACE. 91

Genus 5. COCCONEIS, Ehr.

Frustules adherent, disciform ; valves elliptical, plane, with a median
line and central nodule.

In this genus the frustules are closely adherent by the surface of
one valve to larger Algze, and are usually detached with difficulty.
The markings of the lower are less intense than those of the upper
surface, but in other respects the valves are symmetrical, and Mr. West
informs me that he has found the absence of a central nodule in the
lower valve, as noted by some writers, by no means a constant cha-
racter.

1. Cocconeis Pediculus, Hhr. FF. arched; V. elliptical, somewhat
angular; disc delicately striated ; striz 40 in ‘001". Length :0008
to 0014". v.v.

Ehr. Inf. xxi. 11. Kutz. Bacill. v. 9.

Fresh water. Frequently attached to Cladophora glomerata. Lewes, Aug.
1851; Wareham, Sept. 1851, W. Sm. Lough Mourne Deposit. Peterhead
Deposit, &e.

Plate III. 31. Frustules with endochrome, Frontispiece fig. XXXII.

The strize on this species are seen by a higher power as lines, concentric
with each extremity of the valve.

2. Cocconeis Placentula, Hir. FF. plane, valve elliptical, disc
striated. Length 0011" to :0016". v.v.

Ehr. Inf. p. 194. Ebr. in Kiitz. Bacill. xxviii. 13.

Fresh water: frequent. Wareham, July 1849, W. Sm. Lough Mourne
and Peterhead Deposits. Cantyre Peat and Dolgelly Earth.

Plate III. 32.

3. Cocconeis Thwaitesii, V7. Sm. F. arched; valve constricted
towards the obtuse extremities ; median line sigmoid; dise faintly
striated ; stria 72 in -001". Length :0009" to :0013". v.v.

Cymbella flewella, Kiitz. Bacill. iv. 14. Achnanthidium flewellum, Bréb. in

Kutz. Sp. Alg. p. 54. ad specim. authen. que communicavit cl. De
Brébisson, Jan. 1853.

Fresh water. Near Bristol, May 1848, Mr. Thwaites. Mountains in

pe, BRITISH DIATOMACE.
Forfar, at an elevation of 2800 feet. Near Aberdeen and near Belfast,
Dr. Dickie ; Rescobie, Mr. P. Grant. Marl, Co. Down, Xe.

Plate III. 33. d. outline of ditto in S. V.

4, Cocconeis Scutellum, Hh. V. orbicular or elliptical; striz
concentric with extremities, moniliform, 18 in :001". Length
0006" to ‘0016". v.v.

(. Nodule dilated into a Stauros.

Ehr. Inf. xiv. 8. Kiitz. Bacill. v. 6.

Marine. Very common, and exceedingly variable in size and outline.

Plate III. 34. 3, Supp. Plate XXX. fig. 34.

5. Cocconeis Grevillii, n.sp. V. oval, furnished with transverse
canaliculi; striee moniliform, 15 in ‘001”. Length -0008" to :0025".
V.S.

Quek. H. C. pl. xii. 19?

Marine. Attached to Phyllophora rubens, Sidmouth, communicated by
Dr. Greville. Hastings, Mr. Shadbolt. Poole Bay, W. Sm. (Algoa Bay,
South Africa. Ichaboe Guano.)

Plate II. 35 a. lower valve ; 35 a*. upper valve ; 35 a'. view of upper valve
from within.

6. Cocconeis diaphana, n.sp._V. eliiptical, scarcely siliceous, dia-
phanous; striz obscure. Length -0012" to -0018". v.v.
{&. Nodule dilated into a Stauros.

Marine. Sidmouth, Miss Cutler, communicated by Dr. Greville. Pontac,
Jersey, Aug. 8, 1852, W. Sm.

Supp. Plate XXX. 254.

Genus 6. COSCINODISCUS, Ehr.

Frustules free or adherent, disciform ; valves plane or slightly convex
with a cellular structure.

This genus, though closely related to those which immediately
follow it, finds its nearest allies in the Melosiree, whose genera, from
their filamentous character, stand widely apart in the present work.

BRITISH DIATOMACEA. 93

Were the frustules of Coscinodiscus eccentricus, for example, perma-
nently coherent after self-division, it would be difficult to separate
them in a generic point of view from those of Orthosira nivalis,
W. Sm., which have the same cellular structure of the siliceous valve,
or from those of Melosira aurichalcea, Ralfs, or Orthosira sulcata,
Kiitz., which are furnished with a projecting fringe of silex, the
homologues of the spinous processes in C. eccentricus. It is true that
the Melosiree 1 have mentioned have valves much more convex,
occasionally even cylindrical ; but in Orthosira arenaria, W. Sm., this
difference disappears, and we have frustules as much compressed and
in consequence as narrow on the F. V. as in Coscinodiscus, and
differing principally in the firm and permanent coherence of their
surfaces.

1. Coscinodiscus minor, Hir. Cells of V. circular, margin smooth.

V.S.

Ehr. in Kiitz. Bacill. i. 12?
Fresh water. Aberdeenshire, Dr. Dickie.
Plate III. 36.

2. Coscinodiscus radiatus, Ehr. Cells distinctly hexagonal, ar-
ranged concentrically, largest in the centre of valve, margin smooth.
Diameter :0018" to 0055". v.v.

Kutz. Bacill. i. 18. Prit. Anim. xiv. 39.

Marine. Poole Bay, 1848. Stomach of Scallop, coast of Sussex, W. Sm.
Coast of Norfolk, Mr. Brightwell. Near Folkestone, Mr. Capron. (Peruvian
and African Guano.)

Plate III. 37.

3. Coscinodiscus eccentricus, Hhr. Cells arranged in eccentric
lines, margin spinous. Diameter :0006" to 0038". v.v.
Kitz. Bacill. i. 9.

Marine or brackish water. Poole Bay, Aug. 1848. Near Lewes, July
1850. Stomach of Scallop in great numbers, Feb. 1851.

Plate III. 38.

24 BRITISH DIATOMACE.

Genus 7. EUPODISCUS, Ear.

Frustules free or adherent, disciform; valves convex; disc with
elevated processes.

Closely allied to the last, but differing from it in the less distinctly
cellular structure of the valve, which in some species is wholly absent,
and in the presence of the horn-like processes of the disc, which do
not occur in Coscinodiscus. It differs from Genus 10. in its orbicular
form and in the horns springing directly from the surface of the valve,
while in Triceratium they are confined to the anyles and are formed
by the prolongation of the latter.

1, Eupodiscus Argus, Hhr. Cells of V. irregular in outline, pro-
cesses three or four. Diam. *0065" to 0113". v.s.

Kitz. Bacill. i. 6. £. Germanicus, Kiitz. Sp. Alg. p. 134. Prit. Anim.

xahy, Zul

Marine or brackish water. Thames near Gravesend, Mr. Poulton. Near
Faversham, Mr. Shadbolt. River Orwell near Ipswich, Mr. Hodgson.

Plate IV. 39.

2. Eupodiscus fulvus, n.sp. Cellular structure indistinct, radiate ;
colour of dry valve tawny. Diam. 0018" to 0028". v.v.
Marine. Poole Bay, Sept. 1851, W. Sm.
Plate IV. 40.

3. Eupodiscus crassus, n.sp. Cells circular; V. somewhat opaque ;
colour of dry V. purplish; margin smooth. Diam. ‘0011 to -0021.
V.Ve

Marine. Poole Bay, 1848, W. Sm. Near Ipswich, Mr. Hodgson.
Plate IV. 41.

4, Eupodiscus radiatus, Bai/.? Cellular structure of V. distinct;
cells circular; processes four, radiate, two larger than the others.
V.S.

Marine. Detected by Mr. West among other Diatomacez from the rivers
Orwell and Thames.

Supp. Plate XXX. 255.

BRITISH DIATOMACE. 95

5. Eupodiscus sculptus, n.sp. V. striated, the central striae form-
ing a quatrefoil; processes two. Diam. 0013" to ‘0025". v.s.

Marine. Poole Bay, Sept. 1851, W. Sm.
Plate IV. 42.

Genus 8. ACTINOCYCLUS, Fir.

Frustules free or adherent, disciform; valves cellular, undulated ;
pseudo-nodule central, conspicuous.

The undulations on the surface of the valves appear on the side
view as radiating bands; on the front view their true character is
easily seen, and they at once distinguish this genus from its allies.
It may also be noticed that the cellular structure of the disc is absent
from a small portion (pseudo-nodule) in the centre of the valve.

1. Actinocyclus undulatus, Kiitz. Valve with six rays. Diam.
"0009" to :0040". v.v.

Kitz. Bacill. 1. 24.

Marine or brackish water: frequent. Poole Bay, Sept. 1849. Near Lewes,
Sept. 1850, W. Sm. Near Ipswich, Mr. Hodgson. (Peruvian Guano; Rich-
mond, Virginia.)

Plate V. 43.

Genus 9. ARACHNOIDISCUS, Bail.

Frustules adherent, disciform; valves plane or slightly convex, cel-
lular, marked with concentric and radiating lines; pseudo-nodule
central, conspicuous.

This beautiful genus was, I believe, established by Professor Bailey
of New York, and has been found in abundance upon Algz collected
in Japan, California and South Africa. The discovery of its British
habitat is due to M. De Brébisson of Falaise, who detected a single
frustule of the species described below on Sphacelaria olivacea, Ag.,
collected by Mr. Ralfs at Ilfracombe in North Devon. A minute
description of this species with carefully executed figures has been

26 BRITISH DIATOMACEZ.

given by Mr. Shadbolt in the Transactions of the Microscopical Society
of London, vol. iii. p. 49.

1. Arachnoidiscus Ehrenbergii, Baij]. Pseudo-nodule surrounded
with a double row of puncta, the interior linear, the exterior cir-
cular. Diam. ‘0051" to 0161". v.s.

A. Ehrenbergii, Bail. sic cl. De Brébisson in lit. cum icone photographica
pulcherrima! 4. Japonicus, Prit. Anim. xxiv. 18-21.

Marine. Ilfracombe, Mr. Ralfs.
Supp. Plate XXXI. 256.

Genus 10. TRICERATIUM, Fir.

Frustules free or attached, triangular; valves cellular, angles elevated
or produced.

The triangular form of the frustules separates this genus from all
its allies, from which it is also distinguished by the absence of a
pseudo-nodule, the appearance of such in 7. striolatum? being pro-
bably accidental in the single individual from which the figure was
drawn. ‘The frustules are probably at first attached to larger Algze,
but I have been unable to determine this point from the isolated spe-
cimens which have fallen under my notice. The species hitherto
found in Britain have occurred on the southern and eastern coasts, in
the mud of tidal rivers.

1. Triceratium Favus, Hhr. Cells hexagonal, angles produced into
horn-like obtuse processes. v.s.

Kiitz. Bacill. xviii. 11. Quek. H. C. xii. 22a. Bail. Sound. fig. 54. Prit.
Anim. xiv. 43, 44.

Marine or brackish water. Thames near Faversham, Mr. Shadbolt. River
Orwell near Ipswich, Mr. Hodgson. (Near Charlestown, communicated by
Prof. Williamson.)

Plate V. 44. Supp. Plate XXX. 44.
2. Triceratium alternans, Bail. Cells circular, angles slightly
elevated. v.s.

Bail. Sound. figs. 55, 56.

BRITISH DIATOMACE, oO

Marine. Poole Bay, Aug. 1848. Hove, Sussex, Nov. 1852, very sparingly,
W. Sm. Folkestone, Sept. 1852, Mr. Capron. (Peruvian Guano.)

Plate V. 45. Supp. Plate XXX. 45.

3. Triceratium striolatum ? Ehr. V. with acute angles, not ele-
vated or produced; cellular structure faintly discernible. v.s.

Kitz. Bacill. xviii. 10?

Brackish water. Near Lewes, Oct. 1850, W. Sm. I refer this doubtfully
to the species described and figured by Prof. Kutzing.

Plate V. 46.

Genus 11. CYCLOTELLA, Kitz.

Frustules free or adherent, disciform ; valves convex or plane, striated,
striz rayed.

Closely allied to Coscinodiscus and Melosira, the absence of a cel-
lular structure separating it from the first, the shallow valve and non-
adherent frustule from the second. The undulations on the F.V. of
the species first described, which are by no means constant, are
probably due to an irregular depression in the centre of the valve, a
character which may be also noticed in the second species, but being
less strongly marked in the latter, and the outline being more regular,
the appearance of undulations is not so evident. I have also noticed
in the first species, that although no undulations may be discernible
in the dry frustule, they become apparent when the objects are im-
mersed in balsam.

1. Cyclotella Kiitzingiana, Thw. V. undulated; striz delicate,
extending over half the disc, at margin 20 in 001"; centre of V.
smooth. Diam. :0005" to 0015". v.v.

§. Valve without undulations.

Thw. Ann. 2nd Ser. vol. i. pl. xi. p. C. operculata (. rectangula, Kitz. Sp.
Alg. p. 19. ad specimina que misit cl. De Brébisson, Oct. 1852.

Fresh or brackish water. Near Bristol, Mr. Thwaites. Wareham, Nov.
1848. (3. Lewes, Oct. 1850, W. Sm. Thames, Northfleet, Mr. Shadbolt,
Feb. 1851.

Plate V.47. 4', Sporangial (?) frustule. Frustule with endochrome, Fron-
tispiece, fig. XLVIT.

28 BRITISH DIATOMACE.

2. Cyclotella operculata, Kiitz. V. depressed in centre; striz
obscure, very short, 36 in 001". Diam. :0005" to 0012". v.v.
Ag. Consp. p. 11. Kiitz. Bacill. i. 1.

Fresh water. Plumpton, Sussex, Mar. 1852, W. Sm. Lough Neagh,
Dr. Dickie. Cantyre Peat, &c.

Plate V. 48.

3. Cyclotella antiqua, n.sp. V. convex; striz broad, not reaching
the margin. Diam. -0009" to :0013". v.s.

Fresh water. Lough Mourne and Peterhead Deposits. Cantyre Peat, and
Marl, Co. Down.

Plate V. 49.

4, Cyclotella Rotula, Kitz. V. plane; striz numerous, distinct,
14n-001". Diam. -0015" to -0022". y.s.

Kitz. Bacill. ii. 4. Discoplea atmospherica, Ehr. in Prit. Anim. xxiv. 1 & 2?
Fresh water. Lough Neagh, Dr. Dickie.
Plate V. 50.

Genus 12. CAMPYLODISCUS, Ljhr.

Frustules free, saddle-shaped ; valves equidistant ; canaliculi radiated.

The species included under this genus may all be recognised by
the characteristic bend or contortion of their surfaces. The cost,
as in Epithemia, appear to arise from the presence of minute canals
which form means of communication between the internal cell-mem-
brane and the surrounding fluid. In one species, C. cribrosus, these
appearances are absent; but the presence of foramina on the margin
in this species seems to indicate the existence of canaliculi, though

these are not apparent as distinct costae.

1. Campylodiscus Horologium, /Vi//. V. circular; canaliculi
about 50, in length one-third of the radius; centre of V. smooth.
Diam. *0051" to -0068". v.s.

Prof. Williamson in Ann. Nat. Hist. May 1848.

Marine. Coast of Skye, dredged in 60 fathoms water by Mr. G. Barlee,
communicated by Prof. Williamson.

Plate VI. 51.

BRITISH DIATOMACE. 29

2. Campylodiscus costatus, JV. Sm. V. circular; canaliculi from
30 to 40, in length about half of the radius; centre of V. minutely
punctate. Diam. 0025" to 0050". v.v.

Var. 3. V. somewhat elliptical, disc distinctly punctate.
W. Sm. Ann. 2nd Ser. vol. vii. pl. i. 1. Bright. Inf. pl. ix. 10.

Fresh water. River Frome near Dorchester, May 1849. Near Lewes,
Aug. 1850, W. Sm. Bramley Spring near Guildford, Mr. Capron. Norfolk,
Mr. Brightwell. Lough Mourne Deposit. Peterhead Deposit. Dolgelly
Earth, &c. &e. Var. 3. Cantyre Peat.

Plate VI. 52. \Var. 6. Pl. VII. 52.

3. Campylodiscus Hodgsonii, n. sp. V. nearly circular; canaliculi
very numerous, 100 or upwards, in length about one-third of the
radius ; centre of the disc cellular ; cells circular, in radiating lines.
Diam. *0018" to :0052". ws.

Marine. Near Ipswich, Mr. Hodgson, July 1851. Poole Bay, Oct. 1851,
W. Sm.

This beautiful species varies much in size, but presents throughout its cha-
racteristic features. The disc is frequently traversed by a smooth line cor-
responding with its longest diameter: a F. V. shows us that this line is formed
by a ridge and two contiguous furrows passing across the valve. It is worthy
of remark that the ridges on the two valves of the same frustule are not
uniformly opposite, but cross each other at various angles: a similar circum-
stance may sometimes be noted in Hupodiscus and other disciform frustules.

Plate VI. 63: 5°?

4, Campylodiscus spiralis, V7. Sm. FF. twisted so as to present a
spiral outline; V.elliptical; canaliculi about 60, nearly parallel; centre
of the disc minutely punctate. Longest diam. :0042" to 0083". v.v.

W. Sm. Ann. 2nd Ser. vol. vii. pl.i. 2. Surirella spiralis, Kitz. Bacill. ii. 64?

Fresh water. Bramley near Guildford, Oct. 1848, Mr. Capron. Lanshaw
Spa, near Katefield, Lancashire, Jan. 1852, Mr. Geo. Smith. Norfolk, Mr.
Brightwell.

Plate VII. 54. Frustule with endochrome, Frontispiece, fig. LIV.

5, Campylodiscus cribrosus, W.Sm. V. nearly circular ; disc cel-
lular ; cells irregularly circular, in radiating lines. Diam. 0041" to

“0052" v.v.

30 BRITISH DIATOMACE.

W. Sm. 2nd Ser. vol. vii. pl. i. 3. C. Argus, Bail. Obs. pl. 1. 24. 25. ad
specimina que communicavit Prof. Williamson, Jan. 1852.

Marine or brackish water. Poole Bay, Nov. 1848. Lewes, 1850, W. Sm.
Coast of Norfolk, Mr. Brightwell. (Hudson River.)

Plate VIL. 55.

6. Campylodiscus parvulus, WV. Sm. Valves circular; canaliculi
about 12, minute, in length about two-thirds of radius. Diam. ‘0011"
to °0019". v.v.

W. Sm. Ann. 2nd Ser. vol. vii. pl. i. 4. Prit. Anim. xxiv. 22, 23.
Poole Bay, 1848, W. Sm.
Plate VI. 56.

7. Campylodiscus Ralfsii, n. sp. V. nearly circular, canaliculi
reaching to the median line. Diam. ‘0016" to 0019". vs.

Marine. Ilfracombe, Mr. Ralfs.
Supp. Plate XXX. 257.

Genus 13. SURIRELLA, Turp.

Frustules free, ovate or elliptical ; valves with a longitudinal central
line, and margins produced into alz; canaliculi distinct, usually
parallel.

The only genus with which the present stands in near alliance is
Try blionella, from which it is well distmguished by the prominency of
its ale, the distinctness of its canaliculi, and the usual cuneate form
of its frustules: with no other is it at all likely to be confounded. The
surface of the valve in Swriredla, as in the other Diatomacee, is marked
with transverse lines ; these are usually very faint in the present genus,
but in a few cases they are somewhat conspicuous and have been
noted in the specific descriptions.

1. Surirella biseriata, De Bréb. F.V. linear, oblong; V. elliptical-
lanceolate; alze conspicuous; canaliculi large, 4 to 6 in O01",
usually reaching to central line. Length :0025" to 0083". v.y.

BRITISH DIATOMACE. 31

De Breb. Alg. Falaise, 1835, p. 53. pl. vii. ad spec. authen. que communi-
cavit cl. auctor. Hass. Alg. cii. 1. W. Sm. Ann. 2nd Ser. vol. vii.
pl. ii. 1. Prit. Anim. xvii. 20-26. Jen. Flo. Tun. p. 204. Nav. bi-
Jrons, Ehr. Inf. xiv. 2. Surirella bifrons, Kiitz. Bacill. vii. 10.

Fresh water. Boggy pools frequent, elsewhere occasionally. Wareham,
Dec. 1849 ; Lewes, Sept. 1851, W. Sm. Ashdown Forest, Sussex, Mr. Jenner.
Lough Mourne and Lough Island-Reavey Deposits, and Premnay Peat.

Plate VIII. 57. Frustule with endochrome, Frontispiece, fig. LVII.

2. Surirella linearis, n.sp. V. linear, occasionally constricted,
obtuse or acuminate. v.v.

With the last, and probably varieties of it and S. splendida. Curwen Hill
Lot near Lancaster, Mr. Geo. Smith, 1851. Snow Mud, Ben M* Dhui,
Dr. Dickie. Cantyre Peat, Xe.

Plate VIII. 58.

3. Surirella constricta, W.Sm. F. V. linear, oblong; V. elliptical,
acute, usually with a central constriction ; alae conspicuous; cana-
liculi delicate, 10 to 12 in ‘001", reaching to central line, which is
often inflated. Length :0028” to -0055". v.v.

W. Sm. Ann. 2nd Ser. vol. vii. p. 9.

Brackish water. Near Lewes, Dec. 1850. Poole Bay, Sept. 1851. Lancing,
Sussex, Nov. 1852, W. Sm.

Plate VIII. 59.

4, Surirella turgida, n.sp. V. much inflated, irregular in outline,
occasionally somewhat constricted towards the obtuse extremities ;
canaliculi few, conspicuous, 4 in ‘001". Length :0033" to 0052".
V.S.

Fresh water. Lough Neagh, Dr. Dickie, 1850.
Plate [X. 60.

5. Surirella lata, n. sp. V. elliptical, with rounded ends and
frequently with a central constriction ; canaliculi conspicuous, 3 or
4in‘001"; margin striated; striz 36 in 001". Length -0041" to
0062". v.s.

Marine. Coast of Skye, Prof. Williamson. Ilfracombe, Mr. Ralfs.
Plate IX. 61.

3 BRITISH DIATOMACE.

6. Surirella splendida, Kiitz. F.V. ovate; V. ovate, elongated,
ale distinct ; canaliculi conspicuous, 4 in :001", reaching the central
line. Length ‘0050" to :0072". v.v.

Kiitz. Bacill. vii. 9. ad specim. authen. quee misit amic. De Brébisson. W.

Sm. Ann. 2nd Ser. vol. vii. pl. ii. 2. Nav. splendida, Ehr. Inf. xiv. 1.
Prit. Anim. i. 151.

Fresh water. Near Lewes, Oct. 1850. Ashdown Forest, Sept. 1851, WV. Sm.
Premnay and Cantyre Peat. Dolgelly Earth.

Plate VIII. 62.

7. Surirella nobilis, n.sp. V. linear-ovate ; canaliculi conspicuous,
3 in ‘001", not reaching to the central line. Length -0083" to
*O144!5y.s:

Surirella splendida, W. Sm. Ann. 2nd Ser. vol. vii. pl. ii. 3.

Fresh water. Lough Mourne Deposit. Dolgelly Earth. Raasay Earth.
Lough Island-Reavey Deposit, &c.

Plate VIII. 63.

8. Surirella striatula, Turp. VV. broadly ovate, faintly striated ;
strie 40 in 001"; canaliculi distant, 3 in 001", reaching the central
line. Length :0041” to 0061". v.v.

Kitz. Bacill. vii. 6. W. Sm. Ann. 2nd Ser. vol. vii. pl. ti. 1. MNavicula
striatula, Ehr. Inf. xxi. 15. Prit. Anim. in. 137. Bright. Inf. ix. 2.

Marine or brackish water: common. Poole Bay, July 1848. Newhaven,
Sussex, Feb. 1852, W. Sm. Coast of Norfolk, Mr. Brightwell.

Plate IX. 64. Frustule with endochrome, Frontispiece, fig. LXIV.

9. Surirella Gemma, Hir. F. V. ovate; V. ovate or elliptical ;
alee distinct; canaliculi delicate, unequally distant, reaching central
line; surface of V. striated; striz 48 in -001". Length :0025" to
0058". v.v.

Kitz. Bacill. vi. 11. W. Sm. Ann. 2nd Ser. vol. vii. pl. i. 2. Prit. Anim.

xOYo My Oh Zhe
Marine: common. Poole Bay, July 1849. Shoreham Harbour, Aug. 1850,
&e., W. Sm.

Plate IX. 65.

10. Surirella fastuosa, Hhr. V. ovate, ale small; canaliculi few,
inflated towards the margin; median line turgid. Length 0020"
tocQ025", v.v.

BRITISH DIATOMACE. 33

Kiitz. Bacill. xxviii. 19. W. Sm. Ann, 2nd Ser. vol. vii. pl. ii. 3.

Marine. Poole Bay, Sept. 1848; Pevensey Bay, Oct. 1850, W. Sm.
(Peruvian Guano.)

Plate IX. 66.

11. Surirella Craticula, Hhr. V. lanceolate; alee distinct; cana-
liculi few, small, divergent, reaching the median line. _ v.s.

Kiitz. Bacill. xxviii. 22, W. Sm. Ann. 2nd Ser. vol. vii. pl. iti. 4. Prit. Anim.
xv. 19-20.

Fresh water. Bramley Spring near Guildford, Mr. Capron. River Bann,
Mr. Cocken. Lough Mourne Deposit.

Plate IX. 67.

12. Surirella ovalis, Bréb. V. ovate, acuminate, striated ; striz
36 in 001"; ale inconspicuous; canaliculi marginal, numerous,
12 in 001", Length :0021" to :0038". v.v.

Kiitz. Bacill. xxx. 64. W. Sm. Ann. 2nd Ser. vol. vii. pl. ii. 7.

Fresh water. Near Lewes, Dec. 1852, VW. Sm. Near Bristo), Mr. Thwaites.
Norfolk, Mr. Brightwell. Pilling, Lancashire, Rev. J. Bannister.

Plate IX. 68.

13. Surirella panduriformis, n.sp. V. with a subcentral constric-
tion; extremities rounded; canaliculi inconspicuous. Length
0009" to :0016". v.v.

Fresh water. Iford near Lewes, Oct. 1852, W. Sm.
Supp. Plate XXX. 258.

14. Surirella Brightwellii, JV. Sm. V. orbicular, with one extremity
acute, striated; striae 32 in °001"; al inconspicuous; canaliculi
distinct, marginal, 10 in 001". Length 0011" to ‘0016". v.v.

Surirella Crumena, Bréb. in Kitz. Sp. Alg. p. 38. sic cl. De Brébisson in lit.
cum specim., Sept. 1852.

Fresh or brackish water. Coast of Norfolk, Mr. Brightwell, 1850. Lewes,
Sept. 1851, W. Sm.

Plate IX. 69.

15. Surirella ovata, Kiitz. V. ovate, minute; ale small; canali-
culi marginal, 11 in 001". Length 0008" to 0018". v.v.

Kutz. Bacill. vu. 1, 2, 3.

34 BRITISH DIATOMACES.

Fresh or brackish water. Lewes, March 1851, VW. Sm. Northfleet, Kent,
Mr. Shadbolt, Feb. 1852.

Plate IX. 70.

16. Surirella salina, WV. Sm. V. ovate-elliptical; ala obsolete ;
canaliculi minute, marginal, numerous, 14 in 001". Length 0005"
to 0018". v.v.

W. Sm. Ann. 2nd Ser. vol. vii. pl. i. 6.

Marine or brackish water. Poole Bay, Sept. 1847; Hastings, Aug. 1851,
W.Sm. Timber Pond, W. I. Docks, Feb. 1852, Mr. Shadbolt.

Plate IX. 71.

17. Surirella pinnata, n.sp. V. linear-ovate; alze obsolete ; cana-
liculi large, subdistant, marginal, 15 in ‘001". Length :0006" to
0013". v.v.

Fresh water. Near Lewes, Jan. and Dec. 1852, W. Sn.

PBlates Xu 2.

18. Surirella angusta, Kiitz. F. V. linear truncate; V. linear, acu-
minate; ala obsolete; canaliculi 18 in ‘001". Length -0008" to
0014 Waves

Kiitz. Bacill. xxx. 52. ad specim. que misit amic. De Brébisson, Jan. 1853.
Fresh water. Lewes, Dec. 1852, W. Sin.

Supp. Plate XXXI. 260.

19. Surirella subsalsa, n.sp. F.V. oblong, inflated; V. elliptical-
ovate, striated; striz 30 in :001"; larger extremity rounded, rarely
attenuated; alae conspicuous ; canaliculi distinct, 8 in ‘001". Length
0006" to -0016". v.v.

Fresh or brackish water. ‘* Brooks” near Lewes, Oct. 1852; Newhaven,
Sussex, Dec. 1852, W. Sm.

Supp. Plate XXXI. 259.

20. Surirella minuta, De Bréb. V. ovate-elliptical; ale incon-
spicuous; canaliculi marginal, 14 in -001". Length 0005" to
0009". v.v.

De Brébisson in Kiitz. Sp. Alg. p. 38. ad specimina authentica quae commu-
nicavit cl. Jenner. W. Sm. Ann. 2nd Ser. vol. vii. pl. ii. 5.

Fresh water. Corfe Castle, Dec. 1849 ; Lewes, March 1851, W. Sm.
Plate IX. 73.

BRITISH DIATOMACEA, 35

Genus 14. TRYBLIONELLA, IV. Sm.

Frustules free, elliptical or linear; valves plane; ale submarginal or
obsolete ; canaliculi inconspicuous, parallel.

This genus differs from Campylodiscus in the more elongated form
of its frustules and the absence of the characteristic bend in its
valves; the canaliculi are also more minute and parallel rather than
radiating. It agrees with Swriredla in the presence of ala, but these
arise from the disc, and are not, as in Surirella, prolongations of the
margin. It is also distinguished by its less conspicuous canaliculi,
and by the frustule never assuming the cuneate form so notable in
Surirella.

1. Tryblionella Scutellum, n.sp. V. elliptical, marked with a cen-
tral depressed line; canaliculi obsolete ; ala very short. Length
50058!) to, 0085". v.v.

Surirella circumsuta, Bail. Obs. pl. 1. 36. ad specimina quee communicavit
Prof. Williamson.

Marine. Poole Bay, Nov. 1848, W. Sm. (Hudson River.)
Plate X. 74.

2. Tryblionella gracilis, n.sp. IF. V. linear, attenuate towards the
extremities ; V. linear acuminate; canaliculi parallel, extending to
the central line, 10 to 12 in 001"; ale distinct. Length -0023"
to 0075". v.v.

Fresh and brackish water. Near Lewes, Dec. 1850, and Oct. 1852, W. Sin.
Plate X. 75. Frustule with endochrome, Frontispiece, fig. LXXV.

3. Tryblionella marginata, n.sp. F. V. inflated, extremities ob-
tuse; V. elliptical, acuminate; canaliculi distinct, marginal, 18 in
001"; alz conspicuous. Length :0011" to 0026". v.v.

Fresh and brackish water. Near Lewes, Sept. 1851, W.Sm. Pilling and

Cockerham Marshes, Lancashire, M7. Johnson. Near Belfast, Dr. Dickie.
Plate X. 76. Ideal section of frustule, Pl. X. fig. s.

D 2

36 BRITISH DIATOMACE.E.

4, Tryblionella punctata, n.sp. V. elliptical, acuminate, striated ;
striz moniliform, 31 in -001"; canaliculi obsolete. Length 0012"
to <O021". wiv.

Marine. Coast of Sussex, sparingly, Sept. 1850, W. Sm.
Plate X. 76. a’. Supp. Plate XXX. 261.

5. Tryblionella acuminata, n. sp. V. linear, acuminate; canaliculi
obscure ; striz delicate, 40 in ‘001", interrupted; ale obsolete.
Length :0025" to :0042". v.s.

Marine and brackish water. Poole Bay, June 1849; Belfast Bay, Sept.
1849; near Lewes, Dec. 1850, WV. Sm.

Plate X. 77.

6. Tryblionella angustata, n.sp. V. as in the last species; striz
continuous, 36 in ‘001". Length :0021” to -0040". v.v.
Fresh water. Iford, Sussex, Oct. 1852, W. Sm. Guildford, M7. Capron.
Supp. Plate XXX. 262.

Genus 15. CYMATOPLEURA, I’. Sm.
Frustule free, oblong, or elliptical; valves undulated.

The undulations of the surface of the valves separate the present
genus from both the last ; the absence of alee and canaliculi are further
characters which leave no room for hesitation as to its distinctness.

1, Cymatopleura Solea, /V. Sm. F. V. oblong, linear; V. fiddle-
shaped, symmetrically divided by a central sinus on each margin ;
undulations six ; surface of V. striated ; strize 18 in ‘001". Length
"0042" to 0115". v.v.

W. Sm. Ann. 2nd Ser. vol. vii. pli. 9. Navicula librilis, Ehr. Inf. xii. 22.
Prit. Anim. xvii. 9. Surirella Solea, Kitz. Bacill. iii. 61. Sphincto-
cystis librilis, Hass. Alg. ci. 3.

Fresh water: common. Lewes, May 1850, and Oct. 1852, &e., W. Sin.

Plate X. 78. Frustule with endochrome, Frontispiece, fig. LX XVIII.

BRITISH DIATOMACE. 37

2. Cymatopleura apiculata, n.sp. V. fiddle-shaped, apiculated ;
undulations about four. Length 0021" to -0051". v.v.

C. Solea, W. Sm. Ann. 2nd Ser. vol. vii. pl. ii. 8.

In numerous localities with the former. I am not certain that the present
is entitled to rank as a distinct species ; it is usually much smaller than the
former and of a more rounded outline, but intermediate specimens sometimes
occur, and in Ehr. Inf. xin. 22. fig. 2, copied in Prit. Anim. pl. iii. fig. 155,
we have a form as large as Solea with distinct apicula as in the present species.

Plate X. 79.

3. Cymatopleura parallela, n. sp. V. linear, extremities attenuate,
obtuse. Length :0021" to :0048".

Fresh water. Iford near Lewes, Oct. 1852, W. Sm.

Supp. Plate XXX. 263.

4, Cymatopleura elliptica, JV. Sm. V. broadly elliptical, some-
what acuminate, with four or five undulations ; surface obscurely
striated. Length :0016" to 0055". v.v.

Surirella elliptica, Bréb. in Kiitz. Spec. Alg. p. 37. ad specimina que com-

municavit cl. De Brébisson, Aug. 1852. W. Sm. Ann. 2nd Ser. vol. vi.
pli LOéall Prits Anim: xvi, 7,

Fresh water: frequent. River Frome, May 1849. Plumpton, Sussex,
April 1852. Guildford, Mr. Capron, &e. &c. The larger variety in Lough
Mourne and Peterhead Deposits, Dolgelly Earth, &c.

Plate X. 80.

5. Cymatopleura Hibernica, !V.Sm. V. orbicular, with prominent
subacute extremities; undulations three; striz obscure. Length
50022) tor- 0052". vas

W. Sm. Ann. 2nd Ser. vol. vi. pl. mi. 12.

Fresh water. Lough Neagh, Co. Antrim, Dr. Dickie. River Bann, Mr.
Cocken.

Plate X. 81.

Genus 16. NITZSCHIA, Hass.

Frustules free, elongated, compressed ; valves linear, keeled, with one
or more longitudinal lines of puncta; keel frequently eccentric.

This genus embraces a large number of species, differing in form

38 BRITISH DIATOMACEX.

and size, but all agreeing in a few general characters. The most
important of these is the keeled form of the valves, and the remark-
able inequality, in many of the species, between the portions of the
valve lying on either side of this prominency. This inequality, or, in
other words, this eccentricity of the keel distinguishes Nitzschia from
Amphiprora, in which the keel is also present, while the presence of
a keel and its accompanying line or lines of puncta, together with the
absence of any form of stipes, separate the present from the genus
Synedra, with which several of its species have been united by pre-
vious authors. The true character of the valve may be detected by a
careful examination of the desiccated frustule, and is easily seen in
the figures given in Plates XIII. and XIV. The fractured valve
shown in Pl. XIV. fig. 118. a, and the sections given in figs. 115. 8.
and 118.8. will more particularly serve to illustrate the form of valve
peculiar to the genus.

Seer. I. Frustules sigmoid. (Sigmatella, Kiitz.)

1. Nitzschia sigmoidea, JV. Sm. F. linear, sigmoid, truncated ;
V. linear, suddenly tapering towards the acute extremities; keel
with a single line of puncta; striz 85 in ‘001". Length -0116” to
“O192! Vive
B. F. reflexed ; strize distinct, 42 in ‘001".

Navicula sigmoidea, Ebr. Inf. xin. 15. Synedra sigmoidea, Kutz. Bacill.
iv. 37. Niteschia elongata, Hass. Alg. cn. 12. Sigmatella Nitzschii,
Kitz. Sp. Alg. p. 18.

Fresh water: very common. Lewes, Dec. 1851, W. Sm.
(. Lough Mourne Deposit. Dolgelly Earth.

Plate XIII. 104. 104. F. V. of single valve of var. 6. Frustule with
endochrome, Frontispiece, fig. CIV.

2, Nitzschia Brebissonii, JV. Sm. F. broader and less sigmoid
than the last on the F.V.; V. linear; extremities attenuate, pro-
duced, obtuse; striae 27 in :001"”. Length 0034" to 0092". v.v.

Synedra Armoricana, Kitz. Bacill. iv. 34. Sigmatella Brebissonii, Kiitz. Sp.
Alg. p. 18. ad specimina quee misit cl. De Brébisson, Oct. 1852.

Fresh water. Near Lewes, Oct. and Dec. 1852, W. Sm.

Supp. Plate XXXI. 266.

BRITISH DIATOMACE. 39

3. Nitzschia Sigma, JV. Sm. F.on F. V. linear, gradually tapering
towards the truncated extremities ; V. linear on F. V., somewhat
lanceolate, acute; stria 56 in ‘001’; puncta of keel in a double
row. Length :0050" to 0116". v.v.

Synedra Sigma, Kutz. Bacill. xxx. 14.
Marine or brackish water. Pevensey Bay, Sept. 1850, W. Sm.
Plate XIII. 108.

4, Nitzschia obtusa, n. sp. F. on F. V. linear, with rounded ex-
tremities; V. linear, obtuse; puncta double; striae 56 in -001".
Length :0042" to 0121". v.v.

Brackish water. Shagalieu Marsh, Poole Bay, June 1849, W. Sm.
Plate XIII. 109.

5. Nitzschia spectabilis, n.sp. F. on F. V. linear, sigmoid, trun-
cate; keel nearly central; puncta in 4 rows, the more distant on
each side larger; V. striated. v.s.

Brackish water. Near Ipswich, Mr. Hodgson, Aug. 1851.
Plate XIV. 116.

Sect. II. Valves linear, straight.

6. Nitzschia scalaris, /V. Sm. F. V. linear, inflated towards the
truncated extremities ; V. linear, slightly tapering towards the ex-
tremities, which are somewhat acute; keel eccentric; puncta
double, alternately produced into shorter and longer striz ; surface
of valve distinctly striated; strice 24 in ‘001". Length °0125" to
OL 7O. viv.

Synedra scalaris, Kutz. Bacill. xxvii. 32.
Brackish water. Shagalieu Marsh, Poole Bay, June 1849, WV. Sm.
Plate XIV. 115. Ideal section of frustule, fig. 115 s.

7. Nitzschia linearis, VY. Sm. F.V. linear, with rounded or trun-
cated extremities, occasionally with a slight central constriction ;
V. linear, with acuminate extremities; keel nearly central; puncta
in a single row; striz obscure. Length :0023” to 0075".

Frustulia linearis, Ag. ex sp. authen. quee misit cl. Dr. Greville.

40 BRITISH DIATOMACE.
Surirella multifasciata, Kutz. Bacill. ii. 47. et Synedra oxyrhynchus, Kitz.
Sp. Alg. p. 44. ad specimina que misit cl. De Brébisson, Sept. 1852.

Fresh water: common. Lewes, March 1852, W. Sm. Wray, Mr. G. Smith,
Noy. 1852. (Ceylon, Mr. Thwaites, Nov. 1850.)

Plate XIII. 110. Supp. Plate XXXI. 110.

8. Nitzschia tenuis, /V. Sm. F. V. linear, occasionally slightly
sigmoid, extremities truncate; V. narrow, lanceolate, acute; striz
obscure. Length :0042" to :0083". v.v.

Synedra tergestina, Kutz. Bacill. iv. 33. ad specimina quee communicayit cl.
De Brébisson, Oct. 1852.

Fresh water. Near Lewes, March 1850, W. Sm. Wray near Lancaster,
Mr. G. Smith.

Plate XIII. 111.

Sect. III. Valves lanceolate.

9. Nitzschia spathulata, n. sp. F. V. linear-lanceolate, extremities
inflated; V. lanceolate, acute, with a single row of puncta. Length
0041" to :0083". vs.

“ Nitzschia spathulata,’ cl. De Brébisson inliteris cum speciminibus, Sept.1852.

Marine. Hull, Mr. R. Harrison.
Supp. Plate XXXI. 268.

10. Nitzschia angularis, n.sp._ F. V. lanceolate, truncate; V. lan-
ceolate ; keel central; puncta in a single row; surface of V. longi-
tudinally striated. Length :0041" to :0065". v.v.

Marine. Coast of Sussex, July 1850, W. Sm.
Plate XIII. 117.

11. Nitzschia lanceolata, WV. Sm. F. V. lanceolate, extremities
acute; V. linear lanceolate, acute; keel eccentric; surface of valve
marked by longitudinal lines, 21 in ‘001"; striz faint, 80 in -061".
Length :0048” to :0085"._ v.y.

Surirella curvula, Bréb. in Kitz. Sp. Alg. p. 36. ad specimima quae commu-

nicavit cl. De Brébisson, Sept. 1852.
Marine. Pevensey Bay, Sussex, Nov. 1850, W. Sin.

Plate XIV. 118. Ideal section of frustule undergoing self-division, fig. 118.8.

BRITISH DIATOMACE.®. 41

Sect. IV. Valves arcuate.

12. Nitzschia Amphioxys, V7. Sm. F. V. linear, quadrangular ;
V. elliptical-lanceolate, arcuate, with acute and somewhat promi-
nent extremities; striz distinct, 30 in :001". Length -0016" to
"0043", v.v.

Eunotia amphiowys, Kitz. Bacill. xxix. 44, xxx. 1.

Fresh water: common. Lewes, Jan. 1851, W. Sin.

Plate XIII. 1035.

13. Nitzschia vivax, n.sp. FI. V. linear; V. linear-lanceolate, ar-
cuate, extremities produced into a prominent beak; striz distinct,
30 in 001". Length 0026" to 0056". v.v.

Fresh or slightly brackish water. Near Lewes, Oct. 1852, W. Sin.

Supp. Plate XXXI. 267.

14. Nitzschia parvula, n. sp. V. with central constriction, puncta
obscure, extremities prominent; striz faint, 70 in ‘001", Length
0012" to -0015". v.v.

Marine: encrusting a sponge, Poole Bay, Noy. 1849, W. Sm.

Plate XIII. 106.

15. Nitzschia minutissima, /V. Sm. V. linear; puncta distinct,
with prominent and acute extremities; striz obscure, 72 in -001".
Length -0008" to 0011". v.v.

Synedra dissipata, Kitz. Bacill. xiv. 3. xxx. 53. ad specimina que misit cl.
De Brébisson, Sept. 1852.

Fresh water: on chalk rocks. Near Beachey Head, April 1852, W. Sm.

Plate XIII. 107.

Sect. V. Valves constricted.

16. Nitzschia dubia, V7. Sm. F. V. elliptical, slightly constricted
towards the centre, and tapering towards the somewhat truncate
extremities; keel very eccentric; V. obscurely striated; striz 60
in 001". Length -0042" to 0066". v.v.

. A smaller form.

42 BRITISH DIATOMACE.

{. Synedra constricta, Kutz. Bacill. iii. 70. ad spec. quee dedit amic. De Bré-
bisson.

Brackish water. Near Lewes, Oct. 1851, W. Sm. Hull. Mr. Harrison.
Coast of Norfolk, Mr. Shadbolt.

Plate XIII. 112. Plate XIV. 112.
Var. 8. Supp. Plate XXXI. 112 £.

17. Nitzschia bilobata, V. Sm. F. on F. V. elliptical, with a central
constriction, and round or truncate extremities; V. linear-lanceo-
late, acute; puncta double; keel central; striz distinct, 56 in
7001". Length -0033” to :0058"._ v.v.

Amphiprora latestriata, Bréb. in Kiitz. Sp. Alg. p. 93. sic cl. De Brébisson

in lit. Aug. 1852.
Brackish water. Poole Bay, Oct. 1849. Shoreham, Nov. 1852.
Plate XV. 113.

18. Nitzschia plana, n. sp. F. on F. V. elliptical, with a central
constriction and acute extremities; V. linear-lanceolate, acute;
puncta in a single row; keel eccentric; surface of V. obscurely
striated; striz interrupted, 56 in :001”. Length 0058" to
0076". v.v.

Brackish water. Poole Bay, June 1849, W. Sm.
Plate XV. 114.

Secr. VI. Valves with extremities produced. (Ceratoneis, Kiitz.)

19. Nitzschia birostrata, V7. Sm. F. V. straight, in central por-
tion somewhat lanceolate; extremities produced into extremely
long beaks; keel nearly central; puncta in a single row; striz
obscure. Length :0128" to -0169". v.s.

Ceratoneis longissima, Kitz. Sp. Alg. p. 891. ad specimina quee communi-

ceavit cl. De Brébisson, Sept. 1852.
Marine. Near Walton, Essex, Mr. Topping.
Plate XIV. 119.

20. Nitzschia Closterium, 17. Sm. F. V. arcuate; V. faintly stri-
ated ; strize 90 in ‘001; otherwise as in the last. _ v.v.

BRITISH DIATOMACE. 43

Ceratoneis Closterium, Kitz. Bacill. iv. 11. Ebr. in Prit. Anim. xv. 99.
Marine and brackish water. Hove, Sussex, May 1851, W. Sm.
Plate XV. 120.

21. Nitzschia reversa, n.sp. F. V. lanceolate ; extremities produced
into beaks which are bent in contrary directions; striz 48 in
001"; puncta obsolete. v.v.

Brackish water. Near Lewes, Nov. 1851, ”. Sm.
Plate XV. 121.

99, Nitzschia acicularis, WV”. Sm. F. V. lanceolate, extremities
produced, beaks straight; V. faintly striated; striz 98 in -001".
V.v.

Synedra acicularis, Kiitz. Bacill. iv. 3.

Fresh water. Near Lewes, May 1852, W. Sm.
Plate XV. 122.

23. Witzschia Tenia, JV. Sm. F. V. linear-lanceolate, occasionally
sigmoid, extremities produced ; beaks direct or curved; V. striated,
striz 72 in ‘001"; endochrome in dry frustule apparently arranged
in a spiral manner. _ v.v.

Ceratoneis gracilis, Bréb. in Kutz. Sp. Alg. p. 89. ad specim. quae communi-
eavit cl. De Brébisson, Oct. 1852.

Brackish water. Near Lewes, Sept. 1851, 7. Sm. Braunton, Devonshire,
Mr. Ralfs, Oct. 1849.

Plate XV. 123.

Genus 17. AMPHIPRORA, Ehr.

Frustules free, elliptical, constricted; valves convex, keeled; keel
central, with a longitudinal line, and nodules at centre and ex-
tremities.

The very peculiar frustules of this genus cannot be confounded
with any others, save with those of the fifth section of the last genus,
and from these they are usually distinguished without much difficulty,

44 BRITISH DIATOMACE.

owing to their deeper constriction, the central position of their keel,
and their less firmly siliceous structure. They are frequently found
in large numbers, and with the exception of one species are marine in
their habitat. They are common in the estuaries of all our larger
rivers, and the sheltered bays of the southern and western coasts of
England. I have also examined specimens from the coast of Nor-
mandy, the shores of the United States, and the Arctic Regions.

1. Amphiprora alata, Kiitz. F. twisted; F. V. elliptical, with
rounded extremities; V. linear-elliptical; keel accompanied by a
double line of puncta; surface of V. striated; striz 42 in :001".
Length 0025" to -0052". v.v.

Kiitz. Bacill. ii. 63. Bright. Inf. x. 1.3. Prit. Anim. xvi. 5 & 7. Bail.

Obs. 8, 9, 10.

Marine and brackish water: very common. Coast of Sussex, April and
Aug. 1850, W. Sm.

Plate XV. 124. Frustule with endochrome, Frontispiece, fig. CXXIV.

9, Amphiprora paludosa, n.sp. F. twisted; F. V. elliptical, with
round or truncate extremities ; constriction very deep; V. striated ;
striz 60 in ‘001”. Length -0016” to 0042”. v.v.

In fresh or slightly brackish water. Near Lewes, Sept. 1852, W. Sm.
Supp. Plate XXXI. 269.

3, Amphiprora didyma, n.sp. F. straight, elliptical, deeply con-
stricted; striz faint, 72 in 001". v.yv.
Marine. Lytham, Lancashire, Sept. 1849, W. Sm.
Plate XV. 125.

4, Amphiprora vitrea, n.sp. F. straight; F. V. elliptical, con-
striction very slight; V. lanceolate, striated ; stria 52 in 001".
Length -0023" to ‘0052". v.v.

Marine. Shoreham Harbour, Sept. 1852, W. Sm.

Supp. Plate XX XI. 270.

. Amphiprora constricta, Hhr. I. membranaceous, hyaline
Pp p >) b) 5)

straight, elliptical; V. linear-elliptical, with a central sinus and

BRITISH DIATOMACE. 45

transverse line; stria faint, 68 in ‘001", Length 0024" to 0054".

V.V.

Kiitz. Bacill. xxix. 34. Prit. Anim. xvi. 6?
Marine and brackish water. Coast of Sussex, April 1850, W. Sm.

Plate XV. 126.

Genus 18. AMPHIPLEURA, Kiitz.
Frustules free, linear ; V. with longitudinal ridges.

The structure of the present genus is somewhat obscure. I have
not been able to detect the nature of the ridges so conspicuous on
the front view, nor to determine the parts of the valve from which
they project. Ehrenberg, in his great work Infusionsthierchen, taf. xiii.
fig. iii. 7, gives an ideal section of the frustule, which represents the
ridges as springing from the surface of a convex valve, having between
them a depression which corresponds in position with the ordinary
median line of the Navicule. 1am unable to confirm this description,
although I have on frequent occasions examined the living and dry
valves.

1. Amphipleura pellucida, Kiitz. Frustules linear-lanceolate.
Length +0033" to 0054". v.v.

Kiitz. Bacill. iii. 52. Aulacocystis pellucida, Hass. Alg. ci. 8. Nav. pellu-
cida, Ehr. Inf. xiii. 3. Prit. Anim. m. 140. KVlee les

Fresh water. Lewes, Nov. 1850, VW. Sm. Katefield, Lancashire, Jan.
1851, Mr. G. Smith.

Plate XV. 127.

2, Amphipleura sigmoidea, /V..Sm. Frustules sigmoid. Length
"0058" to °0138". v.v.

Amphipleura rigida, ‘Kitz. Bacill. iv. 30. ad specim. authen. quee communi-
cavit cl. De Brébisson.

Marine and brackish water: forms a distinct pellicle or stratum. Bexhill,
Sussex, Sept. 1850, W. Sm. Lancing, Noy. 19, 1852.

Plate XV. 128.

46 BRITISH DIATOMACEX.

Genus 19. NAVICULA, Bory.

Frustules free, oblong or lanceolate; valves convex, with a median
longitudinal line and nodules at centre and extremities, striated ;
striz resolvable into circular dots.

In the present work, the genus Navicula of Kiitzing is divided into
three; viz. Navicula, Pinnularia, and Pleurosigma. Stauroneis has
already been placed apart both by Ehrenberg and Kiitzing.

The four genera are, I think, sufficiently distinguished from each
other ; Navicula, by the delicacy of its strize and their moniliform
character ; Pinnularia, by the confluent nature of the cellular structure
of its epiderm, which gives to its strize the appearance of distinct ribs
or cost; Stauroneis, by the absence of a central nodule, which is
supplied by a band of silex (Stauros) crossing the valve at right
angles to the median line; and Pleurosigma, by the characteristic
curve of its beautiful frustules.

In a few cases we meet with the semblance of a Stauros in the
genus Pinnularia; but in these instances a closer examination will
show that this appearance arises from the interruption of the cost
merely, and not from the dilatation of the central nodule, which is
still found unchanged.

Sect. |. Valves lanceolate.

1, Navicula rhomboides, Kir. V.nearly quadrangular; striz very
faint, parallel, 85 in :001". Length -0022" to -G037". v.v.
Ehr. in Kitz. Bacill. xxvii. 45, xxx. 44, sic Prof. Kitzing in lit. 1851.

Fresh water. Boggy pools, Sept. 1849, W. Sm. Lancashire, Mr. Johnson,
Aug. 1851. Ben M° Dhui, at an elevation of 3000 feet, Mr. P. Grant.

Plate XVI. 129.

2. Navicula lanceolata, Kiitz. V. lanceolate or elliptical-lanceolate ;
striz parallel, -44 in 001". Length :0012” to -0020". y.v.

Kiitz. Bacill. xxviii. 38. xxx. 48?
Fresh water. Newhaven, Sussex, Dec. 1852, W. Sm. Dolgelly Earth.

Supp. Plate XXXI. 272.

BRITISH DIATOMACEA. 47

3. Navicula Crassinervia, Bréb. V. elliptical-lanceolate; extre-
mities produced ; striz obscure. Length 0013" to -0026". v.s.

“ Navicula Crassinervia,” ad specimina sub hoc nomine que misit cl. De
Brébisson, Sept. 1852.

Fresh water. Wareham, Sept. 1849, 7. Sm. Snow Mud, Grampians,
Dr. Dickie. Dolgelly, Mr. Ralfs.

Supp. Plate XXXI. 271.

4. Iavicula serians, Kiitz. V.acute; transverse striz faint, 60 in
001"; longitudinal distinct, 36 in ‘001"; frustules frequently co-
hering. Length :0017" to -0035". v.v.

Kutz. Bacill. xxvii. 43, xxx. 23, ad specimina que communicavit cl. De
Brébisson in lit. Sept. 1852.

Fresh water: boggy pools. Wareham, Sept. 1849, W..Sm. Forest Row,
Sussex, Mr. Jenner, Jan. 1844. Ben M° Dhui, at an elevation of 3000 feet,
Mr. P. Grant. Lough Island-Reavey Deposit. (Lapland.)

Plate XVI. 130.

5. Navicula cuspidata, Kitz. V. acute; striz parallel, distinct,
36 in 001". Length :0027” to 0062". v.v.

Kutz. Bacill. ii. 24 & 37. ad specim. authen. que misit amic. De Brébisson.
Navicula fulva, Ehr. Inf. xin. 6.

Fresh water: ditches. Lewes, Sept. 1850, W. Sm. Guildford, Mr. Capron.
Belfast, Dr. Dickie. Cantyre Peat. Lough Mourne and Peterhead Deposits.

Plate XVI. 131.

6. Navicula rhynchocephala, [iitz. V. acute; extremities pro-
duced, linear; striae distinct, radiate, 24 in ‘001". v.s.

Kitz. Bacill. xxx. 35?
Fresh water. Belfast, Dr. Dickie.
Plate XVI. 132.

48 BRITISH DIATOMACE.

Sect. II. Valves elliptical, extremities rounded.

7. Navicula Liber, n.sp. F. V. oblong; V. elliptical, with rounded
extremities; striz delicate, 48 in ‘001"; colour of dry V. pur-
plish. v.v.

Marine. Coast of Sussex, Sept. 1851, W. Sm.
Plate XVI. 133.

8. Navicula firma, Kiitz. V. elliptical, somewhat attenuated towards
the rounded extremities; striz obscure, 42 in‘001", parallel. Length
"0025" to :0045". v.v.

3. Extremities suddenly attenuated ; frustule smaller.

B. Kiitz. Bacill. xxi. 10.

Fresh water. Near Lewes, Oct. 1851, W. Sm. Near Belfast, Dr. Dickie.
(3. Lough Mourne and Peterhead Deposits. Cantyre Peat. Marl, Co. Down.
(Vermont, U.S., Prof. Williamson. San Fiore, Italy.)

Plate XVI. 138.

9. Navicula elliptica, n. sp. V. elliptical; striz distinct, 21 in
001", interrupted towards the central line. Length -0912" to
=003 21; "av.v.

Marine. Poole Bay, Sept. 1850; Seaford, Sussex, Aug. 1851, W. Sm.

Plate XVIT. 152. Var. (Sporangial ?) From Poole Bay, 152 a*. Frustule
with endochrome, Frontispiece, fig. CLII.

10. Navicula ovalis, /V. Sm. V. elliptical, occasionally inflated ;
strie distinct, 27 in 001", interrupted. Length 0012" to :0020".
V.V.

Navicula elliptica, Kitz. Bacill. xxx. 55.

Fresh water. Plumpton, Sussex, April 1852, W. Sm. Guildford, Mr.
Capron. Cantyre Peat. Lough Mourne and Peterhead Deposits. Rescobie
and Killicrankie, Mr. P. Grant. (Ceylon, Mr. Thwaites, Nov. 1850.)

Plate XVII. 153.

11. Navicula minutula, n.sp. V. exactly elliptical; striz faint, SO
im -OO!: Length 0006" to 0011". v.v.

Fresh water. Near Lewes, Oct. i852, W. Sm.

Supp. Plate XXXI. 274.

BRITISH DIATOMACE2. 49

Sect. III. Valves elliptical, extremities acute.

12. Navicula Jennerii, 7. Sm. F.V. oblong ; V. twisted, elliptical ;
extremities somewhat acute; stria very distinct, 30 in ‘001", reach-

ing the central line; colour of dry valve a pale purple. Length
0025" to 0068". v.v.

Navicula tumida, Bréb. in Kiitz. Sp. Alg. p. 77. ad specimina quee communi-
ceavit cl. De Brébisson in lit. Sept. 1852.

Marine or brackish water. Rye, Mr. Jeaner. Belfast Bay, Aug. 1849,
and Coast of Sussex, frequent, Feb. 1852, W.Sm. Menai Straits, Prof. Wil-
hamson, July 1852.

Plate XVI. 134. &. outline of F. V.

13. Navicula Westii, n. sp. F. V. oblong; V. straight, elliptical,
acute ; strize delicate, scarcely reaching the central line, 38 in -001" ;
colour of dry valve a dark purple. Length -0032" to :0042". v.v.
Marine: detected by Mr. Tuffen West with the last, May 1852. Shore-

ham Harbour, Nov. 1852, W. Sm.

Plate XVI. 135.

14. Navicula convexa, n. sp. F. V. oblong; V. twisted, acute;
strize very distinct, 21 in °001”, not reaching the central line ; dry
valve colourless. Length :0048" to :0062". v.v.

Marine. Coast of Sussex, Sept. 1851. Harwich, Mr. Shadbolt, May 1852.

Plate XVI. 136. 6. outline of F. V. Frustule with endochrome, Fron-
tispiece, fig. CXXXVI.

15. Navicula elegans, n. sp. V. elliptical acuminate; striz distinct,
24 in ‘001", waved, radiate, absent around the central nodule.
Length :0020" to :0032". v.v.

Marine or brackish water. Poole Bay, June 1849, W. Sm. Cockerham
Marsh, Lancashire, M7. Johnson.

Plate XVI. 137.

16. Navicula patula, W. Sm. V. elliptical, somewhat acute; striz
delicate, 36 in ‘001, not reaching the central line; colour of dry
valve purple. Length :0030" to :0040". v.s.

50 BRITISH DIATOMACEX.

Navicula latiuscula, Kitz. Bacill. v.40. specim. authen. misit cl. De Brébisson.
Fresh water. Marl, Co. Down.
Plate XVI. 139.

17. Navicula palpebralis, Bréb. V. elliptical, acute; strie not
reaching central line, 27 in ‘001". Length 0015" to 0032". _v.s.
“ Navicula palpebralis,” cl. De Brébisson in lit. Sept. 1852.
Marine. Poole Bay, Aug. 1848. Hull, Mr. R. Harrison.
Supp. Plate XXXI. 273.

Sect. IV. Valves inflated; extremities rounded.

18. Navicula obtusa, n. sp. V. elliptical, contracted towards the
rounded extremities; striz distinct, 33 in ‘001", not reaching the
central line. v.s.

Fresh water. Raasay Earth. Marl, Co. Down. Lough Mourne Deposit.
Plate XVI. 140.

19. Navicula Semen, Kiitz. V.oval, contracted towards the rounded
extremities ; striz distinct, 26 in‘001". v.s.
Kitz. Bacill. xxviii. 49.

Fresh water. Peterhead Deposit. Lough Mourne Deposit, &c.
Plate XVI. 141.

20. Navicula affinis, ir. V. elliptical, contracted, and linear to-
wards the rounded extremities. v.s.

Ehr. in Kiitz. Bacill. xxx. 45 ?
Fresh water. Guildford, Mr. Capron.
Plate XVI. 143.

21. Navicula inflata, Kiitz. V. elliptical, inflated; extremities ob-
tuse; striz distinct, 28 in ‘001". vas.

Kiitz. Bacill. ii. 36.
Fresh water. Guildford, Mr. Capron. Peterhead Deposit.
Plate XVII. 158.

BRITISH DIATOMACE. |

22. Navicula gibberula, Kiitz. VV. inflated at the centre, linear
towards the rounded extremities. v.v.
Kitz. Bacill. i. 50*.

Fresh water. Lewes, Feb. 1851, W. Sm. Guildford, Mr. Capron. Lough
Mourne Deposit. Cantyre Peat. Marl, Co. Down. Dolgelly Earth. Ben
M? Dhui, Mr. P. Grant.

Plate XVII. 160.

Secr. V. Valves with extremities produced.

23. Navicula amphirhynchus, Ej. V. linear, abruptly contracted
towards the produced extremities ; striz faint, 48 in °001". Length
"0020" to 0036". v.v.

Kitz. Bacill. xxi. 11.

Fresh water. Lewes, Oct. 1851, W. Sm. Lough Mourne and Peterhead
Deposits. Premnay Peat and Dolgelly Earth. (San Fiore, Italy.)

Plate XVI. 142.

24. Navicula producta, n. sp. V. elliptical, abruptly contracted
towards the produced extremities; striz faint, 42 in ‘001". vv.
Fresh water. Lewes, Oct. 1851, W. Sm. East Shalford, Mr. Capron.
Plate XVII. 144.

25. Navicula ambigua, Hhr. V. elliptical, gradually contracted
towards the obtuse extremities, which are produced ; striz distinct,
parallel, 36 in :001". Length 0021” to :0033". v.v.

Ebr. in Kitz. Bacill. xxvii. 66.

Fresh water. Lewes, Oct. 1851, W. Sm.
Plate XVI. 149. Frustule with endochrome, Frontispiece, fig. CXLIX.

26. Navicula Amphisbzena, Bory. V. elliptical, constricted towards
the extremities, which are rounded and produced; striz delicate,
40in‘001", not reaching the central line. Length 0021"to ‘0032".

6. Extremities slightly produced, obtuse. Length 0017" to 0027". v.v.
Kiitz. Bacill. iii. 41 and 42 8. Ehr. Inf. xii. 7. Prit. Anim. iu. 141.

Hass. Alg. cii. 5.
EZ

52 BRITISH DIATOMACE.

Fresh water. Lewes, Feb. 1851, W. Sm. Wray, Mr. G. Smith. Guild-
ford, Mr. Capron. Var. B. Lewes, April and October, 1852, and Feb. 1853,
W. Sm.

Plate XVII. 147. Var. 6. Pl. XVII. 147 6.

27. Navicula sphzrophora, Kiitz. V. elliptical, constricted to-
wards the extremities, which are rounded and produced; striz
very delicate, 42 in 001". Length :0022" to :0036". v.v.

Kiitz. Bacill. iv. 17. Sp. Alg. p. 75. ad specim. que misit amic. De Bré-

bisson.
Fresh water. Lewes, Oct. 1851, W. Sm. Lough Mourne Deposit.
Plate XVII. 148.

28. Navicula angustata, n. sp. V. very narrow, elliptical, con-
tracted towards the rounded and produced extremities; striz 45
in :001”. Length °0016" to :0022". v.s.

Fresh water. Killicrankie, Mr. P. Grant. Raasay Earth.
Plate XVII. 156.

29. Navicula tumens, n.sp. F.V. inflated; V. elliptical, extre-
mities slightly produced; striz interrupted, faint, 36 in ‘001".
Length *0025" to 0031". v.v.

Brackish water. Newhaven, Sussex, Feb. 1852, W. Sm.
Plate XVII. 150. 6. outline of F. V.

30. Navicula punctulata, n. sp. V. oval, extremities scarcely pro-
duced ; striz distinct, 33 in 001", moniliform. Length :0016” to
0032". v.v.

Marine. Poole Bay, Sept. 1850, and Seaford, Sussex, Aug. 1851, W. Sm.
Plate XVI. 151.

31. Navicula pusilla, n.sp. V. oval, extremities slightly produced ;
strie distinct, 26 in ‘001", radiating, punctate. v.v.

Brackish water. Lewes, Oct. 1850, VW. Sm. Near Belfast, Dr. Dickie.
Plate XVII. 145.

BRITISH DIATOMACE&. 53

32. Navicula tumida, n.sp. V. elliptical, contracted at the ex-
tremities, which are rounded and produced; striz very distinct,
24 in ‘001", reaching central line, punctate and radiate. v.s.
Fresh water. Bramley near Guildford, Mr. Capron, Nov. 1850.

Plate XVII. 146.

33. Navicula dicephala, Kitz. V. linear, constricted towards the
rounded extremities; striz distinct, 26 in ‘001", radiate. v.s.
Kiitz. Bacill. xxviii. 60?
Fresh water. Guildford, Mr. Capron. Lough Mourne Deposit.
Plate XVII. 157.

34. Navicula cryptocephala, Kiitz. V. minute, constricted to-
wards the obtuse extremities; striz faint, 56 in‘001". v.v.

Kitz. Bacill. m1. 20 & 26.
Freshwater streams. Corfe Castle, Dec. 1849, W. Sm. Belfast, Dr. Dickie.
Plate XVII. 155.

Sect. VI. Valves with a central constriction.

35. Navicula didyma, Kiitz. V. elliptical, more or less deeply con-
stricted in the centre; striz interrupted, distinct, 24 in :001".
Length 0014" to 0032". v.y.

soe =

Kitz. Bacill. iv. 7. xxvii. 75. Navicula interrupta, Kitz. Bacill. xxix. 93.
Pinnularia Apis, Ehr. in Kiitz. Bacill. xxvii. 76.

Marine: very common. Sussex, July 1850, W. Sm. (New Zealand.)

Plate XVII. 154. a. and a’. ordinary forms; 6. outline of ditto in S. D.;
a*. var. (Sporangial’?) from Skye, Prof. Williamson. Frustule with endo-
chrome, Frontispiece, fig. CLIV.

36. Navicula binodis, Hr. V. constricted in the centre, extremities
slightly produced; striz obscure. v.s.

Kiitz. Bacill. iti. 35.
Fresh water. Lewes, Aug. 1850, W. Sm.
Plate XVII. 159.

54 BRITISH DIATOMACE&.

Genus 20. PINNULARIA, Ehr.

Frustules free, oblong or lanceolate; valves convex, with a median
line, and nodules at centre and extremities; ribbed or pinnated
with distinct costez not resolvable into dots.

The species in which the cost are absent from the centre of the valve, as
noticed at page 46, belong to Ehrenberg’s genus Stauroptera, but the limits
of that genus are too indefinite to permit me to adopt it in the present work.
1. Pinnularia nobilis, Hhr. V. linear, obtuse, with a central and

terminal inflation; cost radiate, not reaching the median line,

contiguous, 12 in -001". Length -0112" to 0145". v.s.

Navicula nobilis, Kiitz. Bacill. iv. 24. Sp. Alg. p. 80. ad specim. que misit
amic. De Brébisson. Quek. H. C. pl. xii. 1. a.

Fresh water. Lough Mourne Deposit. Dolgelly Earth. Premnay Peat.
Cantyre Peat. (Nova Scotia. Vermont, U.S.)

Plate XVII. 161.

2. Pinnularia major, WV. Sm. V. linear, obtuse, with a central in-
flation ; costz as in the last, 14 in ‘001". Length :0072" to :0122".
V.S.

Navicula major, Kitz. Bacill. iv. 19. Navieula viridis, Ehr. Inf. xiii. 16.
Hass. Alg. ci. 2.

Fresh water. Lough Mourne Deposit. Premnay Peat. Dolgelly Earth.
Mountains of Aberdeen, Dr. Dickie. Cantyre Peat. Peterhead and Lough
Island-Reavey Deposits.

Plate XVIII. 162.

3. Pinnularia viridis, WV. Sm. V. elliptical, attenuated; costz as
in the last, 16 in:001". Length -0021" to-0068". _ y.v.

. Costee parallel, absent from centre of valve.

Navicula viridis, Ehr. Inf. xxi. 12. Prit. Anim. i. 133-136. xviii. 1-6. Kiitz.
Bacill. iv. 18, 20. Quek. H. C. xii. 1. 6. Navicula viridula, Ehr. Inf.
xii. 17.

Fresh water: very common. Wareham, Feb. 1848, W. Sm. Lough
Mourne, Lough Island-Reavey, and Peterhead Deposits. Premnay Peat.
Dolgelly Earth. Cantyre Peat. (New Zealand, Nova Scotia, &c.) Var. .
Lewes, Mar. 1852, WV. Sm. Ben M* Dhui, Mr. P. Grant.

Plate XVIII. 163. Frustule with endochrome, Frontispiece, fig. CLXIII.
Var 2. PX VilL. 163.6.

BRITISH DIATOMACE. 55

4, Pinnularia acuminata, n. sp. V. linear, suddenly attenuated
towards the acute extremities; costa parallel, not reaching the
central line. v.s.

Fresh water. Premnay Peat.
Plate XVIII. 164.

5. Pinnularia oblonga, WV. Sm. V. lanceolate, extremities rounded ;
coste radiate, reaching central line, distant, 11 in 001". Length
0042" to -0066". v.v.

Navicula macilenta, Ehr. Inf. xxi. 13. Navicula oblonga, Kiitz. Bacill. iv. 21.

Fresh water: common. Lewes, Oct. 1852, W.Sm. Belfast, Dr. Dickie.
Peterhead Deposit. Marl, Co. Down.

Plate XVIII. 165. Frustule with endochrome, Frontispiece, fig. CLXV.

6. Pinnularia cardinalis, Hhr. V. linear, extremities rounded;
costz radiate, absent from the centre of V., distant, 9 in O01".
V.S.

Stauroneis cardinalis, Kiitz. Bacill. xxix. 10. Prit. Anim. xv. 72.

Fresh water. Lough Mourne Deposit. Cantyre Peat.
Plate XIX. 166.

7. Pinnularia lata, WV. Sm. V. linear, slightly inflated at the centre ;
cost scarcely radiate, not reaching central line, distant, 7 in 001".
Length -0025” to 0044". v.v.

Navicula lata, De Brébisson in lit. cum specim. Kitz. Sp. Alg. p. 79.

Fresh water: subalpine. Fell End, Lancashire, at an elevation of 900 feet,
Mr. Johnson, May 1851. Snow Mud, on Ben M° Dhui, at an elevation of
3840 feet, Dr. Dickie.

Plate XVIII. 167. d. outline of ditto in S. D.

8. Pinnularia alpina, n. sp. V. elliptical-lanceolate, obtuse; costz
radiate, not reaching central line, distant, 7 to 9 in ‘001". Length
0038" to :0083". v.s.

Fresh water: subalpine. Mountains of Aberdeen, Dr. Dickie. Ben M° Dhui,

Mr. P. Grant. (Falaise, M. De Brébisson.)

Plate XVIII. 168. 4. outline of F. V.

56 BRITISH DIATOMACEA.

9, Pinnularia distans, n. sp. V. lanceolate, acute; costz radiate,
not reaching central line, distant, 10 in :001". Length -0036" to
0052". -v.8.

Marine. Stomach of Scallop, Feb. 1851. Coast of Sussex, W. Sm.
Plate XVIII. 169. 5. outline of F. V.

10. Pinnularia peregrina, Ehr. V. lanceolate, obtuse; costz ra-
diate, reaching central line, subdistant, 13 in 001". Length 0032"
to 0058". v.v.

Ehr. in Kitz. Bacill. xxvii. 52.

Brackish water. Near Lewes, Nov. 1851, W. Sm. Cockerham Marsh,
Lancashire, Mr. Johnson, Mar. 1852.

Platemxevililleal0:

11. Pinnularia acuta, n. sp. V. lanceolate, acute; costz radiate,
reaching central line, 22 in ‘001’. Length 0026" to 0046". v.v.

Fresh water. Plumpton, Sussex, Mar. 1852, W. Sm. Lough Mourne
Deposit. Near Aberdeen, Dr. Dickie. Cantyre Peat. Marl, Co. Down. Dol-
gelly Earth. Peterhead Deposit.

Plate XVIII. 171.

12. Pinnularia directa, n. sp. V. linear-lanceolate, acute; coste
parallel, reaching central line, 20 in -001". Length 0025" to 0037".
V.V.

Marine. Coast of Sussex, Feb. 1852, W. Sm.
Plate XVIII. 172. 6. outline of F. V.

13. Pinnularia radiosa, VV. Sm. V. lanceolate, obtuse ; costz ra-
diate, contiguous, 24 in 001". Length 0016" to °0025". _v.v.

Navicula radiosa, Kitz. Bacill. iv. 23?

Fresh water: frequent. Corfe Castle, Dec. 1849, W. Sm. Wray, Mr. G.
Smith. Peterhead Deposit. Lough Mourne Deposit. Cantyre Peat. Dol-
gelly Earth.

Plate XVIII. 173.

BRITISH DIATOMACEA. 57

14, Pinnularia gracilis, Hhr. V. elliptical-lanceolate, attenuated
towards the extremities ; cost radiate, contiguous. Length -0016"
to 0022". vv.

Navicula gracilis, Ehr. Inf. xiii. 2? Kitz. Bacill. ili. 48? = Mavicula lan-

ceolata, Hass. Alg. ci. 14.

Fresh water: frequent. Lewes, May 1850, W.Sm. Shalford, Mr. Capron.
Plate XVIII. 174.

15. Pinnularia viridula, WV. Sm. V. elliptical-lanceolate, obtuse;
coste faint. Length 0006" to -0016". v.v.

Fresh water. Kingston, Sussex, Nov. 1851, W. Sm.

Plate XVIII. 175.

16. Pinnularia Cyprinus, Hhr. V. elliptical, with a central infla-
tion; extremities somewhat acute; cost radiate, reaching central
line, subdistant, 18 in :001". Length -6016" to -0035". _ v.v.

Ebr. in Kitz. Bacill. xxix. 35?

Marine. Belfast Bay, Aug. 1849, and Coast of Sussex, frequent, Sept. 1851,
W. Sm. Harwich, Mr. Shadbolt.

Plate XVIII. 176. 6. outline of F. V.

17. Pinnularia divergens, n. sp. V. linear-elliptical, somewhat
attenuated towards the rounded extremities; costz radiate at cen-
tre, afterwards divergent, absent from the middle of valve, sub-
distant, 11 in 001".

Fresh water. Premnay Peat. Dolgelly Earth.
Plate XVIII. 177.

18. Pinnularia stauroneiformis, WV. Sm. V. elliptical; costz ab-
sent from the centre of V., not reaching the central line, contiguous,
30 in‘001”". Length -0011” to :0025", v.v.

Navicula Brebissonii, Kitz. Bacill. ii. 49. xxx. 39. Sp. Alg. p. 72. ad specim.
quee dedit amicus De Brébisson.

Fresh water. Lewes, Feb. 1852, W. Sm. Ben M° Dhui, at an elevation
of 3000 feet, Mr. P. Grant.

Plate XIX. 178.

58 BRITISH DIATOMACE.

19, Pinnularia Johnsonii, n. sp. V. linear, with central and ter-
minal inflations ; costz reaching central line, 56in‘001". Length
"0042" to :0072". v.v.

8. Inflations very slight. Length 0025" to :0035". v.v.

Marine or brackish water. Pilling near Lancaster, Mr. Johnson, Feb. 1851.
8. Shoreham, Sussex, Mar. 1851, W. Sm.

Plate XIX. 179. Var. 6. Pl. XIX. 179 B.

20. Pinnularia gibba, Hhr. V. linear, with central and terminal
inflations; cost not reaching central line, contiguous, 30 in ‘001".
V.v.

Navicula acrospheria, Kitz. Bacill. v. 2. Sp. Alg. p. 78. ad specim. quze
misit amic. De Brébisson.

Fresh water. Boggy pools, Wareham, Sept. 1847, W. Sm. Curwen Hill,
Lancashire, Mr. G. Smith. Cantyre Peat. Premnay Peat.

Plate XIX. 180.

21. Pinnularia Tabellaria, WV. Sm. V. as in the last, but central
inflation more distinct; cost subdistant, 22 in O01". v.v.

Navicula tabellaria, Kitz. Bacill. xxviii. 79. Prit. Anim. xv. 21.
Fresh water. Lewes, Sept. 1850, W. Sm.
Plate XIX. 181.

22, Pinnularia acrospheria, VV. Sm. V. as in the last two; infla-
tions more distinct; costa distant, 16 in ‘001". v.v.

Fresh water. Near Lewes, Sept. 1850, W. Sm. Premnay Peat. Dol-
gelly Earth.

Plate XIX. 183.

23. Pinnularia mesolepta, Hhr. V. linear, with three central in-
flations, deeply constricted towards the obtuse extremities ; costa
reaching central line, 24 in ‘001". v.v.

Navicula mesolepta, Kitz. Bacill. xxviii. 73. xxx. 34? Navicula nodosa,

Ehr. Inf. xii. 9.

Fresh water. Ashdown Forest, Sept. 1850, W. Sm. Gardner Street, Sussex,
Mr. Jenner. Near Aberdeen, Dr. Dickie. Marl, Co. Down. Lough Mourne
Deposit. Dolgelly Earth. Premnay Peat. Cantyre Peat.

Plate XIX. 182.

ee aa

BRITISH DIATOMACE. 59

24. Pinnularia interrupta, W. Sm. V. linear, constricted at the
rounded extremities; costz absent from the centre of the valve,
contiguous, 24 in 001". Length -0012" to 0022". v.v.

Stauroneis parva, Kiitz. Bacill. xxix. 23. Sp. Alg. p. 92. specim. misit cl.
De Brébisson.

Fresh water. With the last, and probably only a variety of the same.
Plate XIX. 184.

Genus 21. STAURONEIS, Ehr.

Frustules free, oblong or lanceolate; valves convex; striated, with a
median line and terminal nodules; central nodule dilated into a
band (Stauros) free from striz.

1, Stauroneis Pheenicenteron, Hhr. V. lanceolate, obtuse; stauros
linear, reaching the margin ; striz 33 in 001". Length 0055" to
0066". v.v.

Kitz. Bacill. ii. 53. Navicula Phenicenteron, Ehr. Inf. xii. 1. Prit. Anim.
m. 139. xv. 17 & 18:

Fresh water: very common. Wareham, Sept. 1847; Lewes, Aug. 1850;
Jersey, Aug. 1852, W.Sm. Lough Mourne and Peterhead Deposits. Prem-
nay Peat. Cantyre Peat. (North America.)

Plate XIX. 185.

2, Stauroneis gracilis, Hhr. V. lanceolate, obtuse ; stauros linear,
scarcely reaching the margin; strize very delicate, 45 in -001".
Length °0028"' to 0036". v.v.

Ehr. in Kiitz. Bacill. xxix. 3?

Fresh water. Bindon Abbey, Dorsetshire, May 1849, W. Sm. Wray
near Lancaster, Oct. 1852, Mr. G. Smith. Dolgelly Earth. Lough Mourne
Deposit. Cantyre Peat. (Little Falls, New York, and Nova Scotia.)

Plate XIX. 186.

3. Stauroneis acuta, n.sp. F. V. oblong; V. lanceolate, acute,
inflected at the extremities; stauros dilated towards the margin of
valve; striz 30 in ‘001. Length :0033" to -0057". v.v.

“A species of Navicula,’ Quek. H. C. xii. 26.

60 BRITISH DIATOMACE.
Fresh water. Near Guildford, Mr. Capron, Nov. 1852. Lough Mourne
Deposit. Cantyre Peat. Premnay Peat. (New Zealand: Nova Scotia.)
Plate XIX. 187. Frustule with endochrome, Frontispiece, fig. CLXXXVIT.

4, Stauroneis salina, n. sp. V. elliptical-lanceolate ; stauros linear ;
striz faint, 45 in 001". Length :0016" to :0022". v.v.
Marine. Shoreham, Aug.1851, W.Sm. Folkestone, Nov. 1852, Mr. Capron.
Plate XIX. 188.

5. Stauroneis dilatata, n. sp. V. elliptical, extremities slightly
produced; stauros linear, not reaching the margin; stria 30 in
OO Ge HEE
Fresh water. Aberdeenshire, Dr. Dickie. Cantyre Peat.

Plate XIX. 191.

6. Stauroneis crucicula, n.sp. V. elliptical, extremities slightly
produced; stauros very narrow, linear, reaching the margin. v.y.

Marine. Belfast Bay, Aug. 1849, W. Sin.
Plate XIX. 192.

7. Stauroneis anceps, Hir. V. elliptical, constricted towards the
produced extremities; stauros linear, not reaching the margin;
strize very delicate, 45 in ‘001". y.v.

Ehr. in Kiitz. Bacill. xxix. 4?

Fresh water. Swanage, Dorset, March 1849; Lewes, Oct. 1852, W. Sm.
Lanshaw Spa, Katefield, Lancashire, Mr. G. Smith, Jan. 1852. Ben M*° Dhui,
Mr. P. Grant. Marl, Co. Down.

Plate XIX. 190.

8. Stauroneis linearis, Hir. V. elliptical, inflated at centre and at
the extremities, which are apiculated ; stauros linear, reaching the
margin; striz obscure. v.v.

Kiitz. Bacill. xxx. 26.

Fresh water. Plumpton and Lewes, Sussex, Apr. 1852, W. Sm. Shalford,
Mr. Capron. Premnay Peat.

Plate XTX. 193.

BRITISH DIATOMACE. 61

9, Stauroneis punctata, Kiitz. V. elliptical, extremities produced ;
stauros linear, central; striz radiate, punctate, 27 in ‘001". vs.

Kiitz. Bacill. xxi. 9.

Fresh water. Lough Mourne and Peterhead Deposits. Premnay Peat.
Ben M° Dhui, Mr. P. Grant. Cantyre Peat. (San Fiore, Italy.)

Plate XIX. 189.

10. Stauroneis pulchella, n.sp. IF. V. oblong, constricted at the
centre; V. elliptical; stauros central, dilated towards the margin ;
strie very distinct, 30 in :001", punctate; puncta hexagonal.
Length °0048" to :0096". v.v.

(. Dry valve purplish, somewhat acuminate.

Marine. Coast of Sussex, Aug. 1850, and Poole Bay, Sept. 1851, W. Sm.
§. Torbay, July 1846. Coast of Sussex, Aug. 1850, W. Sm. Near Ipswich,
Mr. Hodgson, Aug. 1851. Harwich, Mr. Shadbolt. (Peruvian Guano.)

Plate XIX. 194. 6. outline of F. VV. Var. B. Pl. XIX. 194 pf.

Genus 22. PLEUROSIGMA, IV. Sm.

Frustules free, elongated; valves convex, sigmoid, with a central lon-
gitudinal line, and nodules at centre and extremities, striated ;
striz resolvable into dots, which are frequently hexagonal.

The sigmoid form of the valve more or less present in all our native
species, at once distinguishes this genus from its allies; but even in
the absence of this feature, which I have noticed to be wanting in at
least one species, discovered by M. De Brébisson, on the coast of
Normandy, the structure of the siliceous valve retains its character-
istic peculiarities. The strize are invariably so closely arranged, that
their discovery and resolution are among the most difficult operations
in microscopy. Their true character has been, in consequence, fre-
quently mistaken ; some observers having considered these appear-
ances of striz to arise from series of perforations, and others from
rows of beads, or minute elevations. With the latter I have been
disposed to coincide, until, aided by the careful manipulation and
excellent object-glasses of Mr. Richard Beck, who has shown me
the hexagonal outline of these supposed beads, I have been led to

62 BRITISH DIATOMACE.

conclude, as I have stated in the Introduction, that the lines arise
from internal structure; that the appearance both of perforations and
elevations may be produced in the same object by a slight alteration
in the focus of the instrument; and that such appearances are merely
optical illusions, produced by the reflection and refraction of the
rays passing through the minute cellular structure of the siliceous
epiderm.

It is evident that no optical effect can confer upon circular eleva-
tions or perforations hexagonal outlines, while it is easy to see how
the latter, when out of focus, or viewed by an object-glass of imper-
fect definition, may assume the semblance of rounded beads or dots.
And, moreover, as the view which regards the strize of Pleuwrosigma as
arising from the cellular arrangement of the epiderm, harmonises the
structure of this extensive genus with that of the other members of
the family, it seems recommended to our acceptance by claims too
strong to be resisted.

Nothing is known of the Reproduction, properly so called, either
of this or of the three preceding genera, multiplication by self-division
being the only mode of increase hitherto detected. While this pro-
cess is actively going forward, the mucus generated by the dividing
frustules is often so considerable as to produce the appearance and
effect of a distinct frond, which assumes the form of a thin pellicle of
some little tenacity. At other times, when the mucous secretion does
not assume the continuity of a pellicle, it invests the individual frus-
tule with a transparent envelope, which has the appearance of an ex-
terior membrane, and has been sometimes mistaken for such. On
one occasion I also met with the frustules of P. Hippocampus enclosed
in mucous or gelatinous tubes, precisely like those of a Colletonema ;
but these conditions must be regarded, for the present at least, as
temporary or accidental, and cannot be admitted into the specific or
generic descriptions.

Owing to the compression of the valves, the scanty development
of the connecting-membrane, and the elongate form of the frustule in
the present genus, the front view is either of a linear or linear-lanceo-
late form; two examples are given in Pl. XXIII. 203 & 207; but
I have omitted a special notice in the case of each species, as I have
not found this feature of much assistance in their discrimination. On
the other hand, as the colour of the dry valve is often conspicuous,
and seems to depend on the structural character of the silicified mem-

BRITISH DIATOMACEX. 63

brane, and also supplies a ready means of discrimination, I have en-
deavoured to record it with as much precision as possible. From
notices forwarded by Mr. Beck, I am disposed to conclude that a
yellow tint in the valve indicates the presence of a distinct hexagonal
structure in its cellular condition, and a purple colour an absence of
such character.

In several species the striae are so closely arranged—or, in other
words, the cellular structure is so minute,—that the power I have ordi-
narily employed has proved insufficient for their resolution. In such
cases I have availed myself of Mr. Beck’s aid, who has succeeded,
with an object-ylass of 4-inch focal length and angular aperture of
120°, in resolving the lines on most of the species alluded to.

Sect. I. Striz oblique.

1. Pleurosigma formosum, JV. Sm. V. linear-lanceolate, twisted,
flexure considerable, extremities obtuse; median line not central ;
colour light chestnut-brown ; striz 36 in ‘001". Length 0141" to
Ol S i. AViVec

W. Sm. Ann. 2nd Ser. vol. ix. p. 5. pli. 1. Prit. Anim. xix. 1.

Marine. Shoreham Harbour, Aug. 1850, W. Sm. Walton, Essex, Mr.
C. Topping.

Plate XX. 195. Frustule with endochrome, Frontispiece, fig. CXCV.

2. Pleurosigma decorum, n. sp. V. lanceolate, acute, angular,
twisted, flexure considerable; median line not central; colour pale
chestnut; striz 36 in ‘001". Length 0098" to °0125". v.s.
Brackish water. Ipswich, Mr. 7. Hodgson, Aug. 1851. Felixstow, Essex,

Mr. C. Topping.

Plate XXI. 196.

3. Pleurosigma speciosum, /V. Sm. V. linear-lanceolate, obtuse;
flexure slight, twisted; median line subcentrai; colour a pale
straw; striz 44 in ‘001". Length :0083" to :0152". v.s.

W. Sm. Ann. 2nd Ser. vol. ix. p. 6. pl.i. 3. Prit. Anim. xix. 3.
Marine. Walton, Essex, Aug. 1851, Mr. C. Topping.
Plate XX. 197.

64 BRITISH DIATOMACES.

4, Pleurosigma rigidum, n.sp. V. linear-lanceolate, flexure slight,
extremities rounded, median line central ; colour pale straw ; striz
48 in ‘001". Length OL 1G" to <0 2!) vas:

Brackish water. Ipswich, Mr. T. Hodgson, Aug. 1851.
Plate XX. 198.

5. Pleurosigma elongatum, WV”. Sm. V. lanceolate, flexure mode-
rate, extremities acute; colour a clear straw; striz 48 in ‘001".
Length °0083" to 0152". v.v.

W. Sm. Ann. 2nd Ser. vol. ix. p. 6. pl.i. 4. Prit. Anim. xix. 4.

Marine and brackish water. Poole Bay, June 1849; Coast of Sussex,
Oct. 1850, W. Sm. Hull, Mr. R. Harrison.

Plate XX. 199.

6. Pleurosigma intermedium, n. sp. V. lanceolate, flexure very
slight, extremities acute; colour pale straw; “stria 55 in “001?
(R. B.) Length -0066" to 0088". v.y.

Marine. Newhaven, Sussex, Mar. 1852, W. Sm. Ipswich Harbour,
Mr. Topping, April 1852.

Plate XXI. 200.

7. Pleurosigma WNubecula, n. sp. V. linear-lanceolate, obtuse,
flexure hardly perceptible; colour very pale; “strize 55 in 001".”
(R. B.) Length :0055" to -0066". v.v.

Marine. Seaford, Sussex, Mar. 1852.
Plate XXI. 201.

8. Pleurosigma delicatulum, /V. Sm. V. lanceolate, acute, flexure
moderate; colour pale pink; striz 64 in 001". Length -0058" to
70108". v.v.

W. Sm. Ann. 2nd Ser. vol. ix. p. 6. pl.i. 5. Prit. Anim. xix. 5.

Brackish water. ‘‘ Brooks”’ near Lewes, Oct. 1850 and Sept. 1852, W. Sm.
Plate XXI. 202.

9, Pleurosigma strigosum, /V. Sm. V. lanceolate, obtuse, flexure
slight; colour pale straw; strie 44 in ‘001. Length -0066" to
0) eee

BRITISH DIATOMACE&. 65

W. Sm. Ann. 2nd Ser. vol. ix. p. 7. pl.i. 6. Prit. Anim. xix. 6.

Marine. Coast of Sussex, Aug. 1850 and Mar. 1852, W. Sm. Rye»
Mr. Jenner. Hull, Mr. R. Harrison.

Plate XXI. 203. Outline of F. V. Pl. XXIII. 203.

10. Pleurosigma quadratum, n. sp. V. quadrangular, acute, flex-
ure moderate ; colour chestnut ; striae 45 in 001". Length 0030"
teOl05". vv.

Pleurosigma angulatum, W. Sm. Ann. 2nd Ser. vol. ix. p. 7. pl. i. 7 & 9.

Prit. Anim. xix. 7 & 9.

Marine or brackish water. Poole Bay, Aug. 1849; Coast of Sussex,
Aug. 1850; Braunton, Devonshire, Mr. Ralfs. Menai Straits, Professor
Williamson, July 1852. Folkestone, Mr. Capron, Nov. 1852.

Plate XX. 204. Outline of a young (?) specimen, 204 (3.

11. Pleurosigma angulatum, WV. Sm. V. lanceolate, angular, acute ;
colour pale chestnut; striz 52 in -001". Length -0066" to -0100".
V.V.

Pleurosigma angulatum 3, W. Sm. Ann. 2nd Ser. vol. ix. p. 7. pl. i. 8. Prit.

Anim. xix. 8. Navicula angulata, Quekett on the Microscope, 1848,
p- 438. pl. viii. 4, 5, 6, 7.

Marine or brackish water. Poole Bay, Aug. 1848 ; Belfast Bay, Aug. 1849 ;
Coast of Sussex, April, May and Aug. 1852, W. Sm. Coast of Lancashire,
Mr. Johnson. Rye, Mr. Jenner. Hull, Mr. R. Harrison. Coast of Norfolk,
Mr. Brightwell.

Plate XXI. 205.

12. Pleurosigma A&stuarii, W. Sm. FF. frequently direct; V.
broadly lanceolate ; extremities obtuse, somewhat produced, flexure
of median line considerable; colour a pale purple; striz 54 in
7001". Length :0028" to :0052". v.v.

Navicula Astuarii, De Bréb. in Kiitz. Sp. Alg. p. 890. ad specim. authen.

que misit cl. De Brébisson, Oct. 1852.
Marine or brackish water. Shoreham Harbour, Nov. 1852, W. Sm.
Supp. Plate XXXI. 275.

13. Pleurosigma obscurum, JV. Sm. V. linear, slightly attenuated,
obtuse, median line not central; colour pale pink; “striz 75 in
001".” (R. B.) Length -0036" to -0062". v.v.

6. A much smaller form: marine.
W. Sm. Ann, 2nd Ser. vol. ix. p.8. pl.i. 11 & 12. Prit. Anim. xix. 11 & 12.
F

66 BRITISH DIATOMACE.

Marine or brackish water. ‘‘ Brooks,” Lewes, Sept. 1850. Var. (3. in-
vesting a sponge, Poole Bay, Nov. 1849, W. Sm.

Plate XX. 206. Outline of smaller var. 206 6.

Sect. II. Striz transverse and longitudinal.

14, Pleurosigma Balticum, /V/. Sm. V. linear, attenuated towards
the obtuse extremities, flexure terminal; colour dark brown; long.
and trans. striz 38 in ‘001". Length :0083" to 0142". v.v.

(. Smaller, more gradually attenuated.
y. Attenuated throughout ; striz obscure.

W. Sm. Ann. 2nd Ser. vol. ix. p. 8. pl. ii. 1, 2 & 3. Prit. Anim. iii. 144.
xx. 1, 2,3. Navicula Baltica, Ehr. Inf. pl. xii. 10. Kiitz. Bacill. iv. 32.

Marine or brackish water: frequent. Poole Bay, Aug. 1848. Belfast Bay,
Aug. 1849. Coast of Sussex, Aug., Sept., Oct. and Nov. 1850, WW. Sm.
Cockerham Marsh, Lancashire, Oct. 1849, Mr. Johnson. 3. & y. Coast of
Sussex, Oct. 1851, W. Sm.

Plate XXII. 207. Outline of young (?) specimens, 207 (6. & 207 y. Out-
line of F. V. Pl. XXIII. 207. Frustule with endochrome, Frontispiece,
fig. CCVII.

15. Pleurosigma Strigilis, 1”. Sm. V. lanceolate, acute, flexure
considerable; colour pale brown; long. striz 40 in ‘001"; trans.
strie 36 in ‘001". Length :0116" to 0142". v.v.

W. Sm. Ann. 2nd Ser. vol. ix. p. 8. pl. ii. 4. Prit. Anim. xx. 4.

Brackish water. Hull, Mr. R. Harrison. ford, Sussex, Oct. 1852, W. Sm.
Plate XXII. 208.

16, Pleurosigma acuminatum, JV. Sm. V. lanceolate, acute, flex-
ure considerable; colour pale brown; long. striae 40 in ‘001";
trans. striz 52 in 001". Length :0050" to :0065". _v.v.

W. Sm. Ann. 2nd Ser. vol. ix. p.9. pl. ii. 5. Prit. Anim. xx.5. Navicula

Stigma, Khr. Inf. xin. 12. Prit. Anim. iii. 146. Kiitz. Bacill. iv. 26.
Marine. Shoreham Harbour, June 1850, W”. Sm. Menai Straits, Prof.
Wilhamson. Higham, Mr. Shadbolt. Folkestone, Mr. Capron, Nov. 1852.

Plate XXJ. 209.

BRITISH DIATOMACEA. 67

17. Pleurosigma distortum, /V. Sm. V. lanceolate, abruptly bent
towards the obtuse extremities; colour pale pink; “ trans. striae 75
in :001"; long. stria 65 in ‘001".” (R. B.) Length 0026" to :0042".
V.v.

W. Sm. Ann. 2nd Ser. vol. ix. p. 7. pl.i. 10. Prit. Anim. xix. 10.

Marine. Coast of Sussex, Aug. 1850, W. Sm. Folkestone, Mr. Capron.

Plate XX. 210.

18. Pleurosigma Fasciola, /V.Sm. V. lanceolate, extremities pro-
duced, flexure considerable; colour pale pink; trans. striz 64 in
-Oo1". Length 0036" to -0048". v.v.

(3. Extremities abruptly bent.

Ceratoneis Fasciola, Kiitz. Bacill. iv. 4.

Marine. Belfast Bay, Aug. 1849. Poole Bay, Sept. 1850. Hastings,
Nov. 1851, W. Sm. Hull, Mr. R. Harrison.

Plate XXI. 211. Var. 6. 211 a’.

19. Pleurosigma macrum, n. sp. V. lanceolate, extremities pro-
duced, flexure terminal, moderate; “trans. striz 85 in:001".” (R. B.)
Length 0083" to :0106". v.v.

Brackish water. I=ford, Sussex, Oct. 1852, W. Sm.
Supp. Plate XXXI. 276.

20. Pleurosigma prolongatum, /V. Sm. V. lanceolate, narrow,
acute, flexure moderate ; “ trans. striz 65 in :001".” (R. B.) Length
0043" to 0060". v.v.

W. Sm. Ann. 2nd Ser. vol. ix. p. 9. pl. i. 7. Prit. Anim. xx. 7.

Marine. Poole Bay, Oct. 1849. Shoreham, Sept. 1852, W. Sm.
Plate XXII. 212.

21, Pleurosigma tenuissimum, n. sp. _V. very narrow, linear-lan-
ceolate, acute, flexure considerable ; striz 48 in ‘001". v.s.

Brackish water. Walton, Essex, Mr. Topping, April 1852.
Plate XXII. 213.

22. Pleurosigma littorale, WV. Sm. V. broadly lanceolate, acute,
flexure considerable; colour purplish; long. striz 24 in ‘001";
trans. striz 50 in ‘00L". Length :0046" to 0063". v.v.

F2

68 BRITISH DIATOMACE.

W. Sm. Ann. 2nd Ser. vol. ix. p. 10. pl. ii. 8. Prit. Anim. xx. 8.

Marine. Coast of Sussex, Nov. 1850, W. Sm. Southampton, Mr. Jenner.
River Orwell, near Ipswich, Mr. Hodgson. (Coast of Normandy, M. De
Brébisson.)

Plate XXII. 214.

93. Pleurosigma Hippocampus, /V. Sm. V. broadly lanceolate,
obtuse, flexure considerable ; colour pale brown ; long. strize 32 in
001"; trans. striz 40 in :001". Length 0050" to :0066". _v.v.

W. Sm. Ann. 2nd Ser. vol. ix. p. 10. pl. ii. 9, 10. Prit. Anim. xx. 9, 10.

Navicula Hippocampus, Ehr. Inf. xiii. 11? Kitz. Bacill. iv. 29? Prit.
Anim. i. 145.

Brackish water. ‘ Brooks”? near Lewes, Sept. 1850, W. Sm. Hull,
Mr. R. Harrison. Titchwell, Norfolk, Mr. Brightwell, Sept. 1851.

Plate XXII. 215. Outline of young (?) specimen, 215 £.

24, Pleurosigma attenuatum, WV. Sm. V. lanceolate, obtuse, flex-
ure moderate; colour purplish brown; long. striz 30 in -001",
trans. striz 40 in :001". Length ‘0075" to :0108". v.v.

W. Sm. Ann. 2nd Ser. vol. ix. p. 11. pl. i. 11, 12 & 13. Prit. Anim. xx.

11, 12 & 13. Navicula Hippocampus, Quekett on the Microscope,

pl. viii. figs. 1, 2,3. Dujar. Inf. xx. 1. Gyrosigma Hippocampa, Hass.
Alg. cit. 11? Navicula attenuata, Kitz. Bacill. iv. 28.

Fresh water: frequent in streams and ditches. River Froome, Dorsetshire,
May 1849; Plumpton, Sussex, and many other places, Apr. 1851, W. Sm.
Guildford, Mr. Capron. Lough Mourne Deposit. Peterhead Deposit. Can-
tyre Peat.

Plate XXII. 216. Outline of F. V. in 8. D. 216d. Outline of young (?)
specimen, 216 /.

25, Pleurosigma lacustre, WV. Sm. V. lanceolate, acute, flexure
considerable ; colour pale brown ; long. and trans. striae 48 in ‘001".
Length :0052" to :0068". v.v.

W. Sm. Ann. 2nd Ser. vol. ix. p. 12. pl. ii. 14. Prit. Anim. xx. 14.
Fresh water. Brooks and ponds near Lewes, Oct. 1851, W. Sm.

Plate XXI. 217.

26. Pleurosigma Spencerii, WV. Sm. V. lanceolate, obtuse, flexure
slight; colour pale brown; “trans. striz 50 in -001", long. striz
55 in -001".” (R. B.) Length -0033” to 0041". v.v.

BRITISH DIATOMACE. 69

W. Sm. Ann. 2nd Ser. vol. ix. p. 12. pl. ii. 15. Prit. Anim. xx.15. Navicula
Spencerii, Quekett on the Microscope, pl. ix.

Fresh water. Near Lewes, Sept. 1850, W. Sm. Reading, Mr. C. Poulton.
Plate XXII. 218.

Genus 23. SYNEDRA, Lhr.

Frustules attached, elongate, rectangular ;_ valves linear or lanceolate,
plane or convex.

In the present genus the frustules, though often found in a free
state, are at first invariably attached to larger Algee, or other plants,
by a cushion-like pedicel, which, in a few cases, becomes developed
into a more or less distinct stipes. In some species the frustules,
after self-division, are speedily detached from this gelatinous cushion,
which in such cases rarely presents us with more than two or four
individuals, as in 8. /unaris. In others, the frustules, after repeated
division, still remain adherent to their pedicel; and the result is a
fan-like band of frustules, as in S. pulchellu, or a stellate cluster,
as in S. radians. The valves are usually furnished with a central
pseudo-nodule and median line, the extremities of which are slightly
dilated; but these characters are variable, and not unfrequently ab-
sent, and are therefore inadmissible in the generic description.

Secr. I. Pseudo-nodule obsolete or very minute; frustule arcuate.

1. Synedra lunaris, Ehr. V. narrow, linear, slightly attenuated,
obtuse; striz 36 in :001". Length :0025" to -0038". v.v.
Ehr. Inf. xvii. 4. Kiitz. Bacill. xiii. i. 5.xv.1. Prit. Anim. iv. 185. Ha-
laria lunaris, Hass. Alg. xevii. 4.

Fresh water. Boggy pools, Dorsetshire, Dec. 1849; near Lewes, Nov.
1852, W. Sm. Coldbath Spring, Tunbridge Wells, Mr. Jenner, Apr. 1842.
Lancashire, Mr. Johnson, Apr. 1852.

Plate XI. 82.

2. Synedra biceps, WV. Sm. V. linear, inflated at the obtuse extre-
mities; stric 48 in ‘001. Length ‘0042" to 0075". v.v.

Eunotia flexuosa, Kitz. Sp. Alg. p. 6. ad specim. authen. que misit cl.
De Brébisson, Jan. 1853.

70 BRITISH DIATOMACE.

Fresh water. Boggy pools, Dorsetshire, Dec. 1849, W. Sm. Dolgelly,
Mr. Ralfs.

Plate XI. 83.

Sect. II. Pseudo-nodule definite, annular.

3. Synedra pulchella, Kiitz. V. lanceolate, slightly constricted to-
wards the obtuse extremities ; pedicel frequently dilated into a com-
pressed dichotomous stipes; frustules forming flabella; striz 33
in 001". Length 0018” to -0046". v.v.

Kiitz. Bacill. xxix. 87.‘ Ctenophora pulchella,” Bréb. sic cl. De Brébisson
in literis cum specim. Oct. 1852.

Fresh water. Penzance, Mr. Ralfs. Jersey, Aug. 1852, W. Sm.
Plate XI. 84. Supp. Plate XXX. 84*.

4. Synedra gracilis, Kiitz. V. as in the last; pedicel not dilated ;
pseudo-nodule less distinct ; frustules scattered ; strize 39 in -001".
Length :0018" to 0041". v.v.

Kiitz. Bacill. mi. 14. xiv. 2. xv. 8.

Brackish water. Poole Bay, Mar. 1848. ‘“ Brooks”’ near Lewes, Apr. 1851,
W. Sm.

Plate XI. 85. Frustules with endochrome, Frontispiece, fig. LXXXV.

5. Synedra acicularis, V7. Sm. V. lanceolate, acute; striz very
faint, 36 in 001". Length :0022" to :0055"._v.v.
Synedra levis, Kitz. Bacill. xv. 8?

Brackish water. Poole Bay, June 1849. Excet, Sussex, March 1850.
Lancing, Sussex, Aug. 1852.

Plate XI. 86.

6. Synedra minutissima, Jiitz. V. linear-lanceolate, extremities
obtuse; striz 36 in ‘001. Length :0009" to 0021". v.v.
Kiitz. Bacill. iii. 30?

Fresh water. Birkenhead, Cheshire, Mr. Shadbolt. Near Lewes, Oct. 1850,
W. Sm.

Plate XI. 87.

BRITISH DIATOMACE. 71

Ssecr. III. Pseudo-nodule indefinite.

7. Synedra salina, n. sp. V. lanceolate, gradually attenuated to-
wards the somewhat obtuse extremities ; striz distinct, 32 in ‘O01".
Length 0075" to :0142". v.v.

Marine. Poole Bay, June 1848, W. Sm.
Plate XI. 88.

8. Synedra radians, WV. Sm. V. linear-lanceolate, extremities some-
what dilated, obtuse; frustules arranged in a radiate manner ; striae
24 in 001". Length :0050" to °0116". v.v.

Synedra splendens, Kiitz. Bacill. xiv. 16. ad specim. quee misit amic. De Bré-
bisson. Hwvilaria Ulna, Hass. Alg. xevii. 2. ad specimina que communi-
cavit cl. Jenner. Diatoma truncatum, Grev. B. F. p. 407.

Fresh water: verycommon. Plumpton, Sussex, Apr. 1852, WV. Sm. Speld-
hurst, Kent, May 1843, Mr. Jenner. Cheshunt, Dec. 1842, Mr. Hassall.
Lough Mourne and Peterhead Deposits.

Plate XI. 89. Pl. XII. 89 8. 89 y. Frustules with endochrome, Frontis-
piece, fig. LXX XIX.

9, Synedra Ulna, hr. V.lanceolate-acute; frustules not radiating ;
strie 24 in :001". Length -0028" to °0085"._ v.v.
§. V. lmear, suddenly acuminated.
f. Kitz. Bacill. xxx. 28.
Fresh water: common. St. Brelades, Jersey, Aug. 1852.
Plate XI. 90. Var. (. Pl. XI. 90 £.

10. Synedra Oxyrhynchus, Miitz. V. lanceolate, suddenly attenu-
ated towards the very acute extremities. v.v.

Kiitz. Bacill. xiv. 8, 9, 10, 11?
Fresh water. Near Lewes, Feb. 1852, W. Sm.
Plate XI. 91.

11. Synedra obtusa, JV. Sm. V. linear, extremities rounded ; striz
24 in ‘001". v.v.

Synedra Ulna, Uhr. Inf. xvii. 1? S. equalis, Kiitz. Sp. Alg. p. 45. ad specim.
quee dedit amic. De Brébisson.

72 BRITISH DIATOMACE&.

In ponds: not uncommon. Lewes, Feb. 1852, W. Sm.

Plate XI. 92.

The last four species are so closely allied, that it is difficult, by a verbal
description, to assign precise characters to each; a close mspection of the
figures will assist in their discrimination, but it will probably be found neces-

sary, upon a further and wider examination, to unite some of those that I
have here felt myself obliged to separate.

12. Synedra capitata, Hr. V. linear, dilated towards the acute
extremities into a triangular head; striz 23 in ‘001". Length
0078" to °0185". v.v.

Ehr. Inf. xxi. 29. Prit. Anim. iv. 185. Kitz. Bacill. xiv. 19. Evzilaria
capitata, Hass. Alg. xevu. 1.

Fresh water: common. Wareham, Sept. 1849, W. Sm. Lough Mourne
and Peterhead Deposits.

Plate XII. 93.

13. Synedra delicatissima, n. sp. V. elongated, very narrow and
gradually tapering to the somewhat acute extremities; striae 27 in
001". Length -0048" to 0092". v.s.

Fresh water. Lough Neagh, Dr. Dickie, 1850.
Plate XII. 94.

14. Synedra longissima, n. sp. V. much elongated, slightly and
gradually attenuated towards the inflated and obtuse extremities ;
stria 28 in 001". Length 0093" to -0183". v.s.

Fresh water. Pond in Botanic Garden, Belfast, 1850, Dr. Dickie.
Plate XII. 95. .

15. Synedra tabulata, Kiitz. V. slightly tapering towards the some-
what inflated and obtuse extremities ; striz marginal, 27 in :001" ;
frustules united into rectangular tablets. Length 0058" to 0087".
V.v.

Kitz. Bacill. xv. 10?

Brackish water. Near Lewes, Sept. 1851, W. Sm.

Plate XII. 96.

BRITISH DIATOMACE. a

16. Synedra affinis, Kiitz. V. lanceolate, acute; striz marginal, 32
in ‘001"; frustules united in flabellate or radiating bundles. Length
"0021" to 0046". v.v.

Kiitz. Bacill. xv. 6, et 11. ad specim. authen. quee dedit amic. De Brébisson.
Marine. Pevensey Bay, Sussex, Apr. 1851.
Plate XII. 97.

17. Synedra Arcus, Kiitz. V. lanceolate, acute; striz marginal,
30 in :001"; frustules on F. V. arcuate, flabellate. Length -0028"
to 0038". v.v.

Kitz. Bacill. xxx. 50?

Marine. Cuckmere, Sussex, Mar. 1851; Jersey, Aug. 1852; Hastings,
Oct. 1852, W. Sm.

Plate XI. 98. Plate XII. 98.

18. Synedra hamata, n. sp. V. linear, or linear-lanceolate, suddenly
attenuated constricted and bent towards the extremities; stricz
marginal, 30 in ‘001". Length -0024" to 0052". v.v.

Fresh water. Plumpton, Sussex, Apr. 1852, W. Sm.
Supp. Plate XXX. 264.

19. Synedra Vaucheriz, Kiitz. VV. linear-lanceolate; striz mar-
ginal, 30 in 001"; frustules somewhat flabellate. Length -0011" to
0018". v.v.

Kiitz. Bacill. xiv. 4?

Fresh water : frequently attached to Vaucheria dichotoma and V. cespitosa.
Lewes, Oct. 1851.

Plate XI. 99.

20. Synedra fasciculata, Kiitz. V. linear-lanceolate ; striz reach-
ing across the valve, 40 in -001"; frustules in rectangular tablets.
v.v.

Kiitz. Bacill. xv. 5? Ewilaria fasciculata, Wass. Alg. xevii. 3. ad specim.
authen. que communicavit cl. Jenner.

Fresh water. Plumpton, Sussex, Apr. 1802, W. Sm.

Plate XI. 100.

74 BRITISH DIATOMACE.

Secr. IV. Pseudo-nodule obsolete; frustule straight.

21. Synedra crystallina, Kiitz. V. much elongated, slightly in-
flated at the centre and extremities; strie reaching across the
valve, 26 in ‘001. Length 0180" to :0266". v.v.

Kiitz. Bacill. xvi. 1. Diatoma erystallinum, Ag. Consp. p. 52. et Grev. B. F.
p- 407. ad specim. authen. quee communicavit cl. Dr. Greville.

Marine. Poole Bay, Sept. 1851, W. Sm.
Plate XII. 101.

22. Synedra superba, Kiitz. V. linear, slightly attenuated from
the centre towards the rounded extremities; striz very distinct,
27 in ‘001", reaching across the valve ; pedicel somewhat elongated.
Length of frustule -0098" to °0205". v.v.

Kitz. Bacill. xv. 13.
Marine. Poole Bay, Nov. 1849, W. Sm.
Plate XII. 102.

23. Synedra Gallionii, Hir. V. attenuate, extremities obtuse ; striz
not reaching across the valve, 36 in ‘001"; pedicel not elongated.
Length of frustule 0060" to 0112". v.v.

(3. A shorter and stouter form.

Ehr. Inf. xvii. 2. Kiitz. Bacill. xxx. 42.
Marine. Isle of Man, Mr. Johnson. 3. Beachy Head, Aug. 1852, W. Sm.
Supp. Plate XXX. 265. Var. 6. Supp. Pl. XXX. 265 £.

24. Synedra fulgens, WV.Sm. V.slizhtly inflated at the centre and
at the rounded extremities; striz reaching across the valve, 36 in
001"; frustules arranged in a flabellate manner upon a branched
pedicel. Length :0068" to °0164". v.v.

Exilaria fulgens, Grev. 8.C. F. pl. 291. Liemophora fulgens, Kitz. Bacill.

xii. 5. ad spec. authen. que misit amicus De Brébisson, Jan. 1853.
Prit. Anim. xvi. 20.
Marine. Poole Bay, Sept. 1851; Jersey, Aug. 1852, W. Sm.
Plate XII. 103.
There is nothing in the structure of the frustule to warrant the separation
of this species from the present genus.

BRITISH DIATOMACEZ. 75

Genus 24. COCCONEMA, Fir.

Frustules stipitate, cymbiform ; valve with a submedian line, having
nodules at centre and extremities.

The frustules of this genus differ in no respect from those of Cym-
bella (Genus 3), and are placed apart solely from the presence of a
stipes. Whether the development of this accessory be esteemed a
generic difference or not, it cannot be denied that it gives a notable
physiognomy to the plant, and affords a ready means of discrimi-
nation. The stipes seems to be an exudation from the frustule,
secreted only during the progress of self-division. It assumes, in the
present and other genera, a membranous consistency and filamentous
form; while the same secretion is present in Cymbéella and many of
the free Diatomaceous forms as a mucous stratum, and in others as a
gelatinous cushion or prolonged pedicel.

Where it possesses a filamentous character it invariably branches
in a dichotomous manner,—a necessary consequence of the self-division
of the frustules, and the circumstance that each filament or branch is
the secretion of a separate frustule. Thus, when self-division is com-
pleted, the extension of the filament below the frustules is suspended,
a joint or articulation is formed at the base of the dividing frustule,
aud each of the half-new frustules begins anew, in its progress towards
special self-division, the secretion of a new joint or internode; and a
dichotomy is the result. Conjugation and the formation of Sporangia
in the present genus have been observed by Mr. Thwaites in C. lan-
ceolatum and C. Cistula, and by myself in both these species and
C. parvum.

1. Cocconema lanceolatum, Hir. F.V. lanceolate, obtuse; V. elon-
gated, slightly inflated at the centre of the concave margin ; striz
moniliform, 21 in ‘001". Length -0043" to 0058". v.v.

(3. Much elongated (Sporangial?). Length -0083!" to :0098".

Ehr. Inf. xix. 6. Kiitz. Bacill. vi. 3. Dujar. Inf. xx. 4. Prit. Anim. iv. 195.
Hass. Alg. ci. 1. In Conjugation, Thw. Ann. vol. xx. pl. xxii. C.

_ Fresh water: frequent. In Conj. River Froome, Dorsetshire, Mar. 1847.
Cockshut stream near Lewes, Ap. 1850. Plumpton, Sussex, Ap. 1852, WV. Sm.

76 BRITISH DIATOMACE.

Aberdeenshire, frequent, Dr. Dickie. Lough Mourne and Peterhead De-
posits. Premnay Peat. Dolgelly Earth. Marl, Co. Down. Cantyre Peat.
Lough Island-Reavey Deposit. (Little Falls, N. Y., Oregon, and Nova Scotia;
New Zealand.) 3. Lough Neagh, Dr. Dickie.

Plate XXIII. 219. Frustules with endochrome, Frontispiece, fig. CC XIX.

2, Cocconema cymbiforme, Hir. F.V. linear-oblong; V. narrow,
concave margin scarcely inflated; striz moniliform, 21 in :001".
Length :0016" to :0032". v.v.

Ehr. Inf. xix. 8. Kitz. Bacill. vi. 12. Hass. Alg. ci. 2.

Fresh water: not so frequent as the last, and scarcely distinct from it.
Near Wareham, Apr. 1848; Lewes, May 1851, W.Sm. Near Bristol,
Mr. Thwaites. Wray, Lancashire, Mr. G. Smith. Lough Mourne and
Peterhead Deposits. Marl, Co. Down. Cantyre Peat.

Plate XXIII. 220.

3. Cocconema Cistula, Hir. F. V. nearly linear, obtuse; V.much
bent, distinctly inflated on the concave margin, obtuse ; strize moni-
liform, 24 in 001". Length :0008" to :0034". v.v.

Ehr. Inf. xix. 7? Kiitz. Bacill. vi. 1. Hass. Alg. ci. 3. In Conjugation, Thw.

Ann. vol. xx. pl. xxu. E. Cymbella reniformis, Ag. Consp. p. 10. ad
specim. authen. que misit cl. Dr. Greville.

Fresh water: frequent. Near Lewes, Mar. 1850. In Conj. Plumpton,
Sussex, Apr. 1852, &c., W. Sm. Aberdeenshire, Dr. Dickie. Lough Mourne
Deposit. Dolgelly Earth, &c. &e.

Plates XXIII. 221. XXIV. 221. Frustules with endochrome, Frontis-
piece, fig. CCXXI.

4, Cocconema parvum, n. sp. F. nearly direct; F. V. oblong;
V. scarcely inflated on concave margin; striz moniliform, 21 in
001". Length -0009" to :0016". v.v.

Fresh water. Surface of Chalk cliff, Beachy Head, Aug. 1850. In Con).
Apr. 1851, W. Sm.

Plates XXIII. 222. XXIV. 222.

BRITISH DIATOMACEZ.

“I
Lo |

Genus 25. DORYPHORA, Kiitz.

Frustules stipitate, lanceolate, or elliptical ; valve with a median line ;
nodules obsolete.

Distinguished from the last by the median line dividing the valve
into two symmetrical parts, and by the absence of distinct nodules.
The second species, upon which the genus has been founded by Pro-
fessor Kiitzing, has been seen by him in its living state, attached by
a short stipes to larger Algae. I have only found it in my gatherings
after the frustules have become detached from their filaments; but
the first species has occurred to me abundantly in a living state, and
I have been able to refer it with confidence to the present genus, to
which it is more closely allied than to Cocconema, with which genus
writers have hitherto classed it.

1. Doryphora Boeckii, WV. Sm. F. V. lanceolate, obtuse; V. lan-
ceolate, acute; striz moniliform, 24 in :001". Length :0026" to
70053". v.v.

Cocconema Boeckii, Ehr. Inf. xix. 5. Kiitz. Bacill. vi. 5. Quek. H.C. xii. 7.

Marine. Poole Bay, Mar. 1849, W. Sm.
Plate XXIV. 223.

2. Doryphora Amphiceros, Kiitz. V. orbicular, elliptical, or ellip-
tical-lanceolate; striz moniliform, 18 in ‘001". Length 0012" to
"0033!5, -v.8:

Kiitz. Bacill. v. 10. xxi. 2. Prit. Anim. xvii. 21. Rhaphoneis, Ehr. in Bail.
Sound. 61-65.

Marine. Poole Bay, Sept. 1851, &c., W. Sm. River Thames, Mr. Shad-
bolt. Near Ipswich, Mr. Hodgson.

Plate XXIV. 224. a! and a", outlines of other forms.

Genus 26. GOMPHONEMA, 49.

Frustules stipitate, cuneate; valves variable in outline, striated, with
a median line and nodules at centre and extremities.

The cuneate form of its frustules, arising from the unequal develop-
ment of the connecting-membrane, distinguishes Gomphonema from

78 BRITISH DIATOMACE.

the genera which have preceded it, and the presence of nodules in
its valves from Podosphenia and Rhipidophora, with which the pre-
sent genus has sometimes been confounded. The latter genera are
also exclusively marine, while the species of Gomphonema, with one
exception (and that a species doubtfully connected with the present
genus), are all inhabitants of freshwater streams and ponds. The
same mode of branching characterizes the stipes of the present genus
as that noticed under the genus Cocconema; and excluding the excep-
tional species just mentioned, this appendage, in the present as in that
genus, when fully developed, consists of an elongated dichotomous
filament. Conjugation and the formation of Sporangia have been
observed by Mr. Thwaites in G. Berkeleyi, G. tenellum, and G. curva-
tum; and by myself in those species, G. capitatum and G. marinum.

1. Gomphonema geminatum, 4g. F.V. slightly cuneate, truncate ;
V. inflated at the centre and constricted towards each extremity,
of which the one more distant from the stipes (the upper) is enlarged
and rounded; striz moniliform, 24 in :001". Length -0041" to
ODE MEE eee

Ag. Syst. p.12. Grev. C. F. pl. 244. fig. 2. Harv. Man. p. 207. Realfs,
Ann. vol. xu. pl. xvii. 3. Hass. Alg. xevii. 1. Kiitz. Bacill. xiii. 2.
Echinella geminata, Lyng. Tent. lxx. p. Gomp. ampullaceum, Grey. B. F.
p- 410. ex specim. authen. quee communicavit cl. Dr. Greville.

Fresh water: subalpine streams, not uncommon. Pentland Hills, Dr.
Greville. Dolgelly, Mr. Ralfs. Wray, Lancashire, Mr. G. Smith. Ben
M* Dhui, Mr. P. Grant. Aberdeenshire, Dr. Dickie. Lough Mourne De-
posit. Dolgelly Earth.

Plate XXVIT. 235. Frustules with endochrome, Frontispiece, fig. CCXXXV.

2. Gomphonema constrictum, Hhr. F.V. distinctly cuneate; upper
extremity rounded, lower obtuse; V. more or less constricted to-
wards the upper extremity, attenuated below; striz 27 in ‘001".
Length :0012" to 0024". v.v.

Kiitz. Bacill. xin. 4. Gomp. truncatum, Ehr. Inf. xviii. 1. Hass. Alg. xeviii. 2.

Gomp. pohlieforme, Ralfs, Ann. vol. xii. pl. xvii. 4. Gomp. geminatum,

Quek. H. C. xii. 4.

Fresh water: frequent. Lewes, May 1850, &c., 1”. Sm. Harrison’s Rocks,
Sussex, Mr. Jenner. Lough Mourne Deposit. Peterhead Deposit. Dol-
gelly Earth, &e.

Plate XXVIII. 236.

BRITISH DIATOMACE. 79

3. Gomphonema acuminatum, Hhr. fF. V. cuneate, slightly in-
flated at centre, and crested at the upper extremity; V. constricted
triangular and apiculate above, attenuated below ; striz 24 in -001"..
Length :0011" to :0028". _ v.y.

(. V. much elongated and slightly constricted below. Length :0031" to
0042".

y- V. cuneate at larger extremity, constriction often obsolete.

Ehr. Inf. xviii. 4. Kiitz. Bacill. xiii. 3. ad specim. quee dedit amic. De Bré-
bisson. Prit. Anim. xvi. 23. Hass. Alg. xcix. 1. Gomp. minutum,
Ralfs, Ann. vol. xii. pl. xvii. 5.

Var. 3. Gomp. coronatum, Kitz. Bacill. xxi. 12.

Fresh water: frequent. Lewes, Nov. 1851, W.Sm. Lough Mourne and
Peterhead Deposits. Var. 3. Dolgelly Earth. Rescobie, Mr. P. Grant.
Var. y. Lewes, Feb. 1853, &c. W. Sm. (San Fiore, Italy. Little Falls, New York.)

Plate XXVIII. 238. a, a', & 6. Var. B. 238 B. Var. y. 238 a! & al".

4. Gomphonema cristatum, Raifs. F.V. obovate, crested; V. ob-
ovate, apiculate; lower extremity acute ; stria 24 in‘001", Length
0009" to :0022". v.v.

Ralfs, Ann. vol. xii. pl. xviii. 6. Hass. Alg.c.1. Gomp. Augur, Kitz. Bacill.
xxix. 74?

Fresh water. Shoreham, Kent, Dec. 1842; Farnham, Surrey, Jan. 1844,
Mr. Jenner. Pond, St. James’s Park, London, Jan. 1852, Mr. Shadbolt.

Plate XXVIII. 239. Frustules with endochrome, Frontispiece,
fig. CCXXXIX.

5. Gomphonema dichotomum, Kii/z. F.V. slightly cuneate, trun-
cated; V. lanceolate, acute; striz 34 in ‘001". Length -0011” to
70018". v.v.

(. Stipes incrassate ; frustules flabellate, obtuse.

Ralfs, Ann. vol. xi. pl. xvii. 7. Kitz. Bacill. viii. 14. Hass. Alg. xcix. 2.
Gomp. minutum, Ag. Consp. p. 34. ex specim. authen. quee communi-
cavit cl. Dr. Greville. Gomp. gracile, Ehr. Inf. xvii. 3.

Fresh water. Wareham, Jan. 1850. Penzance, Mr. Ralfs. Marl, Co.
Down. Premnay Peat. Var. 6. Plumpton, Sussex, Apr. 1852, W. Sm.

Plate XXVIII. 240. Var. 3. 240 8. Frustules with endochrome, Frontis-
piece, fig. COXL.

80 BRITISH DIATOMACEZ.

6. Gomphonema tenellum, /V. Sm. Stipes very short; F.V. linear,
truncate; V. lanceolate, extremities slightly produced; strize 30 in
001". Length 0006" to :0014". v.v.

Gomp. micropus, Kiitz. Bacill. viii. 12. ad specim. que dedit amic. De Bré-
bisson. In Conjugation, Thw. Ann. vol. xx. pl. xxii. fig. D.

Fresh water. Wareham, Dorsetshire, Mar. 1848; near Lewes, Sept. 1850,
W. Sm. Near Bristol, Mr. Thwaites. Wray, near Lancaster, Mr. G. Smith.
Cantyre Peat. Marl, Co. Down.

Plate XXIX. 243.

7. Gomphonema capitatum, Hir. Stipes quite distinct; F.V.cu-
neate; V. slightly attenuated towards the upper extremity, which
isrounded ; much attenuated towards the lower, which is somewhat
acute; striz 27 in°001". Length -0009" to 0014". v.v.

Ehr. Inf. xvii. 2. Kiitz. Bacill. xvi. 2.
Fresh water. Lewes, May 1850, W. Sm.
Plate XVIII. 237.

8. Gomphonema olivaceum, Hr. Frustules and stipes forming
mucous masses; F. V. distinctly cuneate; V. slightly attenuated ;
upper extremity rounded, lower acute; striz 28 in ‘001”". Length
0004" to -0018". v.v.

Ehr. Inf. xviii. 9. Kiitz. Bacill. vii. 13, 15. ad specim. quee dedit amic. De
Brébisson. Echinella olivacea, Lyng. Tent. lxx. c. 1, 2, 3. Gomp.
minutissimum, Grev. 8. C. F. tab. cexliv. 1. ex specim. quee communicavit
cl. Auctor. Gomp. Berkeleyi, Ralfs, Ann. vol. xii. pl. xviii. 8. Hass.
Alescs 2.

Fresh water: in streams, frequent in winter and spring. River Froome,
Dorset, in vast quantities, Dec. 1849. River Ouse, Sussex, equally abundant,
Feb. 1852. Henfield, Sussex, Mr. Jenner. Duddingston Loch, Dr. Greville,
Mar. 1826.

Plate XXIX. 244.

9. Gomphonema intricatum, Kitz. F. V. almost linear, truncate ;
V. lanceolate, obtuse ; strize 30 in‘001". Length -0007” to -0021".
V.V.

Kitz. Bacill. ix. 4.

Fresh water: forming a velvet-like stratum on the surface of a chalk cliff.
Beachy Head, Sussex, Aug. 1850, W. Sm.

Plate XXIX. 241.

BRITISH DIATOMACE. 81

10. Gomphonema Vibrio, Kir. V. almost linear, very slightly at-
tenuated, obtuse ; striz 22 in ‘001". Length :0021" to-0031". v.v.

Ehr. in Kiitz. Bacill. xxix. 75.

Fresh water. Wray near Lancaster, Mr. G. Smith, Aug. 1851. Lough
Mourne and Peterhead Deposits. Marl, Co. Down.

Plate XXVIII. 242.

11. Gomphonema ? curvatum, (iitz. Stipes elongated, filamentous
and dichotomous; F. V. curved; V. enlarged towards the upper
extremity, which is rounded and inflected, attenuated towards the
lower, which is acute; nodules absent in the convex (outer) valve ;
striz 30 in :001". Length :0007" to 0021". v.v.

6. Strize more distinct, 22 in ‘001".

Kiitz. Bacill. vii. 1. Gomp. minutissimum, Ehr. Inf. xvii. 5. Ralfs, Ann.
vol. xii. pl. xviii. 9. Hass. Alg.c. 3. In Conj. Thw. Ann. vol. xx.
pl. xxii. fig. B. Prit. Anim. xiv. 9, 10, 11,12 & 17.

Fresh water: ponds, very common. Near Belfast, Aug. 1849 ; Plumpton,

Sussex, Apr. 1852, W. Sm. Pond, St. James’s Park, Jan. 1852, Mr. Shad-
bolt. Var. (3. Shoreham, Kent, Mr. Jenner, 1843.

Plate XXIX. 245.

12. Gomphonema ? marinum, /V’.Sm. Stipes incrassated, branching
in an irregular manner; F. and V. as in the last species; striz 35
in 001". Length 0005" to -0021". v.v.

Gomp. curvatum, 3. marinum, Kitz. Bacill. viii. 3. Prit. Anim. xvi. 11.

Marine: frequent. Coast of Sussex, Oct. 1851, &e. In Conj. Mar. 1852,
W. Sm.

Plate XXIX. 246.

The last two species are characterized by several peculiarities. The curved
form of their frustules, and the want of symmetry in the valvular markings
are notable circumstances, which seem to place them apart, while the inflection
of the upper extremity of the valve, easily recognised upon a side view, is a
feature not found in any other species of Gomphonema. The last circumstance
would seem to point to Rhipidophora as their appropriate position; but the
presence of a central nodule on the inner surface, and the more perfectly sili-
ceous nature of the valves, forbid their union with that genus. The species
are so closely allied to each other, that it becomes difficult to distinguish them
by a verbal description, if we confine our attention merely to the frustules ; but
the general appearance of the growing plants, arising from the characters of
their stipes, is very different, and their habitats are so wide apart, that there
can be no doubt of their distinctness.

G

io 9)
bo

BRITISH DIATOMACE.

Genus 27. PODOSPHENIA, Ejhr.

Frustules attached, sessile, cuneate; valves convex, obovate, inflected
at the larger extremity, striated, traversed by a longitudinal median
line.

This genus is placed by Professor Kiitzing at the head of his second
tribe, viz. Diatomee vittate. The Vitte, upon the presence of which
he has constituted this division, do not seem to me to be special
organs, but modifications in the outline of the valve, which in the
present genus is slightly inflected at its larger extremity, causing on
a front view the appearance of notches at the spot where the valves
unite with the connecting membrane, and the foramina exist. The
apparent prolongation of this notch to the lower extremity of the frus-
tule, is nothing more than the valvular suture which is seen in all the
Diatomaceze. The appearance of two notches at one extremity in the
same frustule arises from the progress of self-division; for on the
first formation of the new half frustules, the inflected portions of each
valve are in close proximity, and but one notch and one “ vitta” can
be detected. An examination of the frustules, given in Plate XXIV.
figs. 225 and 229, will show the gradual progress of self-division,
and the various appearances consequent thereupon. A side view
of a single valve after maceration in acid, as in Pl. XXIV. 2254,
shows the true form of the valve, and the outline of the inflected por-
tion. We have here the first stage in a modification of the form of
the valve, which, in its more complete development in Tabellaria and
Grammatophora, will remind us of the binate form of many of the
Desmidiez, in which the loculi of the cell are united by a narrow
connecting isthmus.

The only very evident distinction between the present and succeed-
ing genus, is the presence in Rhipidophora of an elongated and fre-
quently dichotomous stipes; but a close examination of the frustules
shows us that the distinct and even moniliform striz, so conspicuous
in Podosphenia, are almost wholly wanting in our native species of
Rhipidophora.

1. Podosphenia Ehrenbergii, Kiitz. F. V. truncate at the upper
extremity; V. acute at both extremities; striae moniliform, 27 in
001". Length :0025" to 0055". _v.v.

BRITISH DIATOMACE&. 83
Kiitz. Bacill. ix. 13. Prit. Anim. xvi. 14. Podosphenia cuneata, Ehr. Inf.
xvii. 8.
Marine. Shoreham Harbour, Aug. 1850, WV. .Sm. Torbay, Mrs. Griffiths.
Plate XXIV. 225.

bo

. Podosphenia ovata, n.sp. IF. V. rounded at the upper extre-
mity; V. rounded at upper, and acute at lower extremity; striae
moniliform, 24 in °001". Length :0033" to :0042". v.y.

Marine. Shoreham Harbour, Aug. 1850, W. Sm.

Plate XXIV. 226.

3. Podosphenia Lyngbyei, Kiitz. IF. V. truncate at upper extre-
mity; V. rounded at upper, and acute at lower extremity; striz
delicate, 46 in ‘001”. Length :0011" to 0033". v.y.

Kitz. Bacill. x. 1, 2. Prit. Anim. xvi. 13. Podosphenia abbreviata, Ehr.
Inf, xvit. 7.

Marine. Coast of Sussex, frequent; June and Aug. 1850, W. Sin.
Plate XXIV. 227.

4. Podosphenia Jurgensii, Kitz. I. V. truncate at upper extre-
mity; V. rounded at upper, and acute at lower extremity; strice
very faint, 48 in ‘001". Length 0025” to 0031". v.s.

Kitz. Bacill. ix. 12. Styllaria cuneata, Ag. in Grey. B. F. p. 408. ad specim.
authen. quee communicavit cl. Dr. Greville.

Marine. Torbay, Mr. Ralfs.
Plate XXV. 228.

5. Podosphenia gracilis, Hir. F.V. almost linear, truncate; V.
scarcely siliceous; strize obscure. Length -0011" to ‘0021". v.v.

Ehr. Inf. xvii. 6. Kitz. Bacill. ix. 10.
Marine. Jersey, Aug. 1852, W. Sm.
Plate XXIV. 229.

Ge

84 BRITISH DIATOMACE.

GENus 28. RHIPIDOPHORA, Kitz.

Frustules stipitate, cuneate ; valves convex, obovate, inflected at larger
extremity, traversed by a median line.

1. Rhipidophora paradoxa, Kiitz. Stipes dichotomous; frustules
on F. V. obovate, rounded at the upper extremity; V. rounded at
upper, acute at lower extremity, occasionally faintly striated.
Length -0016" to 0025". v.v.

Kiitz. Bacill. x. 5. Echinella paradoxa, Lyng. Tent. Ixx. fig. E. Gompho-

nema paradoxum, Ag. Consp. p. 34. ad specim. quae communicavit cl.
Dr. Greville. Ralfs, Ann. vol. xii. pl. xvii. 10.

Marine: frequent. Jersey, Aug. 1852, W. Sm. Penzance, Mr. Ralfs.
Aberdeen, Dr. Dickie. Frith of Forth, Dr. Greville.

Plate XXV. 231.

2. Rhipidophora elongata, Kiitz. Stipes dichotomous; F.V. nearly
linear, truncate ; V. somewhat acute ; striz obscure. Length :0032”
to 0042". v.s.

Kiitz. Bacill. x. 6? Gomphonema tinctum, Ag. Consp. p. 35. ad specimina
que communicavit cl. Dr. Greville.

Marine. Frith of Forth, Dr. Greville, 1849. Cromarty, Mr. Johnson.
Plate RIXVE 232.

3. Rhipidophora Dalmatica, Kiitz. Stipes incrassated, irregularly
branched; F.V. truncate; V. very narrow, somewhat acute; striz
obscure. Length :0008” to :0016". v.v.

Kitz. Bacill. ix. 7?
Marine. Hastings and Beachy Head, Sussex, July 1850, W. Sin.
Plate XXV. 230.

BRITISH DIATOMACEA., 85

Genus 29. LICMOPHORA, 4g.

Frustules cuneate, stipitate; stipes incrassate, irregularly branched ;
valves convex, elongated, inflected at larger extremity, and traversed
by a longitudinal median line.

The frustules of the present genus differ in no essential respect
from those of Rhipidophora. They are, it is true, longer and narrower,
and probably less firmly siliceous; but none of these circumstances
seem to be of generic importance. The separation of the genera must
therefore rest upon the fan-like arrangement of the frustules, upon
the summit of an incrassate and irregularly dichotomous pedicel,
which occurs in Licmophora. This character is however of more im-
portance than might at first view appear, as it indicates a peculiarity
in the self-dividing process. In Rhipidophora paradowa and elongata,
self-division is immediately followed by the separation of the half-new
frustules and a dichotomy in the filamentous stipes; while in the pre-
sent genus the frustules remain for some time coherent, and continue
dividing and multiplying on the summit of the pedicel, which becomes
elongated and incrassated at each successive repetition of the process.

A branching, or rather longitudinal rupture of the pedicel takes
place at irregular intervals, and the entire plant presents us with
more or less complete flabella on the summit of the branches, and
imperfect flabella or single frustules irregularly scattered throughout
the entire length of the pedicel. Rhipidophora Dalmatica possesses
the same character to a certain extent; but the flabella are much
less perfect than in the present genus, while its pedicel is oceasion-
ally so abbreviated as to ally it to Podosphenia.

I have given, in accordance with the authority of my predecessors,
two species of the present genus; but I am far from satisfied that
they are truly distinct; and I am disposed to believe that a wider
comparison of specimens will necessitate their union. The fronds
of both are parasitic upon the larger marine Algz, upon Zostera
marina, and upon various species of Zoophytes.

1. Licmophora splendida, Grev. F. V. nearly linear, frequently
attenuate, and rounded at the upper extremity; V. imperfectly

86 BRITISH DIATOMACE.

siliceous, attenuate towards the larger extremity. Length of F.
“0033” to :0078". v.s.
Grev. B. F. p. 408. Echinella flabellata, Ehr. Ynf. xix.1. Prit. Anim. iv.

192. Inemophora flabellata, Kitz. Bacill. tab. xii. figs. 1, 2,3 & 4. ad
sp. authen. que misit amicus De Brébisson, Jan. 1853.

Marine. Appin, Captain Carmichael, and Saltcoats, Rev. Dr. Landsborough,
from specimens in Dr. Greville’s herbarium.

Plate XX VI. 233. Plate XXXII. 233.

2, Licmophora flabellata, Ag. F.V. cuneate, truncate; V. rounded
at the upper extremity, nearly linear. Length of F. :0033”" to
0058". viv;

Ag. Consp. p.41. L. radians, Kitz. Bacill. xi. 4. Ewilaria fiabellata, Grev.
S. C. F. pl. 289. ad specimina quze communicavit cl. Auctor.

Marine. Torbay, July 1846; Poole Bay, Sept. 1848 and Oct. 1851,
W. Sm. Appin, Captain Carmichael, 1826. Torbay, Mrs. Griffiths. Sal-
combe, Mr. Ralfs. Aberdeen and Larne, Dr. Dickie.

Plate XXVI. 234. Pl. XXXII. 234. Frustules with endochrome, Fron-
tispiece, fig. CCX XXIV.

TO

Vy @<Zby

THE GENERA AND SPECIES DESCRIBED IN VOL. I.

The names printed in italics are synonyms.

ACHNANTHIDIUM,
Kitz.
flexellum, Bréb. ...
ACTINOCY.CLUS «0.5.
undulatus
AMPHIPLEURA
pellucida
PIGLA Cw NGUtze veloc
sigmoidea
AMPHIPRORA......---

eoececree

COUMSEICtAl ese seecee
Gidyma.....5...2-o00 :
latestriata, Bréb....
paludosa
vitrea

eoecseeeeses
eee oceescseccee
eeeecerceese

2 eostata
hyalina

lineolata, Kiitz. ...
membranacea
minutissima.........
ovalis

Cee sccsescce

Pe erceeeesse
eoecee

2 tenera
ARACHNOIDISCUS «se
Ehrenbergii.........
Japonicus, Prit. ...
AULACOCYSTIS, Hass.
pellucida, Hass. ...
CAMPYLODISCUS ...
Argus, Bail..........
costatus
GMO OUE) Gescoccason
Hodgsonii
Horologium.........
parvulus
IRalisiigesesces.scs ce
SpPItalis|sc.cceedtcss sc
CERATONEIS, Ehr.
ARCUS KiuUtZe, seneee
Closterium, Kitz...
Fasciola, Kiitz. ...
gracilis, Bréb.......
longissima, Kiitz...

eocecse eevee

eee eecesseee

Page

Page
COCCONETS)......ccc0ve |
diaphanaie...ccese- 22
Grevillliieeceese sees 22
Redicultistesceceeee = 2)
Placentula ......... 2)
Scutellum ......... 22
Thwaitesli ......... 21
COCCONEMA ......0. 75
Boecku, Ehyr. ...... 17
Cistulatereeceeeeee 76
cymbiforme ......... 76
lanceolatum......... 7h5)
ToeIAWULI, | ooeaosenacs 76
CoSscCINODISCUS...... 22
eccentricus .......++ 23
TOVIOKOT® aaquccanucoonee 23
TAGIAGUSHecceeeeeeees 23
CTENOPHORA, Bréb.
pulchella, Bréb. ... 70
CYCHOTELUANs sce: 27
ANGIQUAL rsceceraceee' 28
Kiitzingiana ...... O7/
operculatal) sc... 28
operculata 8. rect-
angula, Kiitz.... 27
Rotullayesiicsccrescns 28
CYMATOPLEURA ... 36
apiculata .........++. 37
ellipiieayeecseescetass 37
Hibernica ......... 37,
parallelay <osnsscevae 37
Soleaw: secheanteasess 36
CYMBELDA.c..as-ccee WW
ALM Smeeconeoe ences 18
2 Arcus, Hass....... 16
cuspidata .........0.- 18
Khrenbergiiz....2-. W7/
flecella, Kiitz....... 21
Helvetica............ 18
maculata .........0- 18
reniformis, Ag...... 76
Scotieavenctsce sc sicins 18
turgida, Hass..:.... 12
Zebra, Hass...... Soo) NB
DIATOMA.
truncatum, Grev.... 71

erystallinum, Ag....
DIscopiea, Ebr.
atmospherica, Ehv..
DoryYPHORA
Amphiceros.........
Boecku
ECHINELLA, Lyng.
flabellata, Ehy. ....
geminata, Lyng....
olivacea, Lyng.
paradoxa, Lyng....
EpirHEeMiA
alpestris
alpestris, Kitz. .
ANTES peek sles faeces
COMStIICt ate. ce seece ce
gibba
STANUATH se cccvecoves
Hyndmanii
longicornis
Miiseullustecesceee ess
ocellata
proboscidea .........
rupestris
SOLeXis ccc sascdoserse
turgida.......eeceeees
ventricosa
Vertagus, Kitz. ...
Westermanii
Zebra
EuNoTIA
Arcus
Amphioxys, Kiitz...
Diadema
diodon
flexuosa, Kiitz......
ghoba, Prite w.ccases
eraciliss.sscsbacdesnee
granulata, Ehy. ...
NTO Narccoogooooc
tetraodon...........-
(HALON uenondaoeaoc
turgida, Ehy. ......
Westermanii, Ehy..
PAAR LOU scoosoacoc
EUPODISCUS ,.....0..

ae ceeecee

eee ceererace

eeesesees

seeeecoce

eee eereecvoes

eee reereecee

ereeceree

weoeee

eee oot eeesecee

seeeoeeeseee

eee

woes eee e esses

a <M, QB ~¥

a\

“

/s
LIBRARY }=5

!

4

88

IAT OUS) onc eassacces eos
GLASSUSsece-scceseese
fulvus
Germanicus, Kiitz.
radiatus
sculptus
EXILARIA, Grey.
capitata, Hass.
fasciculata, Hass...
flabellata, Grev. ...
fulgens, Grev. ......
lunaris, Hass. ......
Ulna, Hass..........
FRUSTULIA, Ag.
linearis, Ag.
GoMPHONEMA
acuminatum
ampullaceum, Grev.
Augur, Kitz. ......
Berkeleyi, Ralfs ...
capitatum
constrictum .......+.
coronatum, Kitz...
CLIStAbUIM sees deseeae
curvatum.:........
dichotomum
gracile, Khr.
geminatum
geminatum, Quek. .
intricatum
IM ALINUM ssa steele seers
Micropus, Kiitz. ...
minutissimum, Ehr.

ee eee cee eecee

eee ore ceeeee

eoecee

eeeeee

eseeee

eoeece

minutissimum,Grev.

minutum, Ralfs
minutum, Ag. .....-
olivaceum
paradoxum, Ag. ...
pohlieforme, Ralfs.
tenellum
tinctum, Ag.
truncatum, Ehr. ...
Vibrio
GyRosigMA, Hass.
Hippocampa, Hass.
Himantipium, Ehr.
tetraodon, Bréb. ...
LICMOPHORA.........
fabellataeiscccss
flabellata, Kiitz. ...
fulgens, Kitz..2....
splendida.........s+
radians, Kiitz.
INAGVATGUIG AGS eet eisesere
acrospheria, Kitz.
Afstuarti, Bréb....
affinis
ambigua
amphirhynchus .
Amphisbeena

Amphora, Ehr.

en esesee

eeeeee

ee re

eet ewes eneee

INDEX.

angulata, Quek. ...
angustata............
AT Cus EI: ceca ee sls
attenuata, Kiitz....
Baltica, Ehr. ......
bifrons, Ehr.
bINOdISteesesseeeeeees
Brebissonii, Kiitz..
convexa
Crassinervia
cryptocephala ......
CUSPIGACHicnsteseee:
dicephalass...ss--4-
didyma
elegans
elliptica
elliptica, Kiitz......
WORT, | Geadocosac rane
fuloa, Ehr. .........
graba, Mbt...
gibberula ..........
Omactlise Wintel tess sae
Hippocampus, Ehy.
imequalis, Khy.

inflata
interrupta, Kitz...
Jenner
lanceolata
lanceolata, Hass...
lata Brebiteesscase
latiuscula, Kiitz....
Liber
librilis, Ehr.
macilenta, Ehr. ...
major, Kitz. ......
mesolepta, Kiitz....
THINULUA esses ense es
nobilis, Kitz. .....-
nodosa, Ehr
ODEUSA ceaseless
oblonga, Kiitz......
ovalis
palpebralis
patulagece-cercecncoe
pellucida, Ehr.

eeecece

see eeerecces

eoeccesecces

se eecerecene

Ser eeesesoee

seer cere

eeeeee

ee eereees

Phenicenteron,Khyv.

producta ...0.......
punctulata .........
PUSUlay eateectes
radiosa, Kiitz......
rhomboides .........
rhynchocephala ...
SEMICM: san. sceeeeceees
SGRIAMS)aqeeneassee eee
Sigma, hr. ......
sigmoidea, Ehr. ...
Spencervi, Quek....
sphzrophora
splendida, Khyr......
striatula, Ehr.......
Tabellaria, Kitz...

NItzscHia

PLEUROSIGMA

TUMENS .ccccceccene
CUM De saseceaeceee
tumida, Bréb. ......
viridis, Ehr.
viridula, Ehr. .....-
viridula, Kitz.

Westil cs .casdasaaead

Acicularis ....20-e+es-
Amphioxys ...... nas
angularis ..2..-csewes
Brebissoni
bilobata
birostrata......... ae
Closterium
dubia
elongata, Hass......
lanceolata

eeeeeeece

sew e cores eeeee

obtusa «.ts-seseseneee
parvula
plana
TOVEISAscacceusecaheee
scalaris...... oouesenee
SIQMA....c.cscasaees
sigmoidea s+. eee
spathulata
spectabilis
tenuis
Tenia
vivax

eeeesocce

eeceeeeeseeeree

PINNUDARIA seceseeee

acrospheeria.......+.
acuminata
acuta
alpina
Apis, Bhr. <:ccsce
Cardinalis..secsecesss
Cyprinus. ......0..00.
GireCtaleccsecceneeces
Gistans ssscneceenenee
divergens......... oes
gibba
gracilis
mnterrupta
Johnsonii
lata
HOH seooacoac pnoeer
mesolepta .........
MObilisueceeseeeeeeee
oblonga
PCLESTIOA aceanaeees
TAdIOSAsencesesse cater
stauroneiformis ...
Tabellaria
viridis
viridula

eee eeeeereeecee

eee eee eee eescee
ee

eee eeeeeeeeneeccee

ser eeeeeeees

we eecsees

fete eee eeene

acuminatum ......
TS VENI Aa bCcoascnor

Page
angulatum e....... 65
angulatum, W.Sm. 65
attenuatum ......... 68
I altieumalsccsscesee =< 66
decorum ...... ssteca? 63
delicatulum......... 64
distortum ........ 5 (y/
elongatum ......... 64
asciolay sssececssess 67
formosum ......... 63
Hippocampus ...... 68
intermedium ...... 64
NACUSENON seecsenecces 68
MGEOLAle) Seceecnessiee 67
TAYE. gooobacoo00C 67
Nubecula............ 64
OUSCUTUMEs ceees. ses 65
prolongatum ...... 67
quadratum ......... 65
FIPIOUM, <se0eeecc0s. 64
RPeclOSUmM! "<........ 63
Spenceri...... castee 68
NETIOUIS” 5. ..-525e0 66
strigosum......... 64
tenuissimum ..... 5 Oy
PODOSPHENIA ..... §2
abbreviata, Ehr.... 88
cuneata, Ehr. ...... 85
Ehrenbergil......... 82
SEACH IS cersnecenaeess 83
SUEPECMSH cose. 0000: 83
Wye DYEl. onns.500055 83
OVATE iccesccescuseeas 85
RHAPHONEIS, Ehr.... 77
RHIPIDOPHORA 84
Dalmatica ......... 84
elongata, «.....002.0: 84
PatAlOKA -nscssc.00s 84
SIGMATELLA, Kiitz.
Brebissonii, Kiitz.. 38
Nitzschii, Kiitz.... 38
SPHINCTOCYSTIS, Hass.
librilis, Hass. ...... 36
STAUROPTERA, Ehr. 54
STAURONEIS ......... 59
DOI: Ao Sean an arene 59

INDEX.

anceps
cardinalis, Witz...
Crucicula......... ae
dilatata
STACIISe cede sdes sce
linearis......... Fascas
parva, Kitz. ......
Phoenicenteron
pulchella
punctata .......+....
salina
STYLLARIA, Ag.
cuneata, Ag.
SURIRELLA
ANGUSTA ...eeereeeee
bifrons, Kiitz.......
biseriata
Brightwellii.-......
circumsuta, Bail....
constricta
Craticula........ Begs
Crumena, Bréb. ...
curvula, Bréb.......
elliptica, Bréb.
fastuosa
Gemma
lata

eee reece resene

see eeercoree

ore esceee

eee reer tenee
oe ri

Pe ceewesereerecees

MIMUtaeeseoneeeceene

nobilis
ovalis
ovata
panduriformis
pinata
Salma, sec... Maoesnes
Solea, Kitz.
spiralis, Kiitz.
Splendidaycccssseere-
striatula
subsalsa
turgida......... seein
SYNEDRA
acicularis ......s0...
acicularis, Kiitz....
equalis, Kiitz.......

sence reeceseses

Pere Corer eseeee

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weecessoscce

Cee ecevseses

a eee ror eneee

multifasciata, Kiitz.

Areus
Armoricana, Kiitz.
biceps
capitata
constricta, Kitz...
erystallina ...... eee
delicatissima
dissipata, Kiitz. ...
fasciculata
ilu Pega eoeeononcce Soi
Gallioni ...
PTACIIS swaseneaeenence
hamata
levism Koutzeeceeeeer
longissima
lunaris
minutissima
@ ORE) anooodcone acts
Oxyrhynchus
Oxyrhynchus, Kitz.
pulchella .......2....
radians
salina

scalaris, Kiitz......
Sigma, Kiitz. ......
sigmoidea, Kiitz....

Ce eeeeseveees

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@eoreresee

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splendens, Kiitz....
superba ....+2...00.
tabulata < oe src.+ess

Tergestina, Kitz...
Ulna
WP, BNW Scoooncae
Vaucheriz .........
TRICERATIUM
alternans
Favus
striolatum
TRYBLIONELLA......
acuminata
angustata............
STOCUISae sme enae eee
marginata
punctata
Seutellum

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PRINTED BY TAYLOR AND FRANCIS,

RED LION COURT, FLEET STREET,

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Price 1s. 6d. each Slide.

MICROSCOPIC PREPARATIONS OF THE DIATOMACE.

Smita and Beck supply the following Diatomacez described in the Synopsis.
As each specimen has been examined by the author of that work, the au-
thority of these mountings may be relied upon by those desirous of correctly
identifying these interesting and beautiful objects.

Diatomaceous Earths in Balsam.

Peterhead Deposit. Lough Island-Reavey Deposit.

Premnay Peat.
Dolgelly Earth.
Lough Mourne Deposit.

Cantyre Peat.
Marl Co. Down.

Diatomacee in Balsam, or mounted Dry.

No. of No. of
Species Species.
. Epithemia turgida. 45. Triceratium alternans.

. Epithemia Westermanii.
. Epithemia rupestris.

. Epithemia gibba.

. Epithemia ventricosa.

Epithemia Zebra. 47. Cyclotella Kutzingiana.
Epithemia Argus. 50. Cyclotella Rotula.

. Epithemia proboscidea. 57. Surirella biseriata.

. Epithemia Sorex. 59. Surirella constricta.

. Surirella splendida.
. Surirella striatula.
. Surirella Gemma.

. Surirella ovalis.

15. Eunotia Arcus. 70. Surirella ovata.

18. Eunotia triodon. 71. Surirella salina.

23. Cymbella maculata. 75. ‘Tryblionella gracilis.
24. Cymbella Helvetica. 76. Tryblionella marginata.
25. Cymbella Scotica. 77. Tryblionella acuminata.
31. Coeconeis Pediculus. 78. Cymatopleura Solea.
32. Cocconeis Placentula. 80. Cymatopleura elliptica.
33. Cocconeis Thwaitesii. 81. Cymatopleura Hibernica.
34. Cocconeis Scutellum. 82. Synedra lunaris.

35. Cocconeis Grevillii. 83. Synedra biceps.

37. Coscinodiscus radiatus. 84. Synedra pulchella.

38. Coscinodiscus eccentricus. 89. Synedra radians,

41,

. Eupodiscus fulvus.

Eupodiscus crassus.

: Synedra Ulna.
. Synedra tabulata.

No. of No. of
Species. Species.

97. Synedra affinis. 236. Gomphonema constrictum.
102. Synedra superba. 238. Gomphonema acuminatum.
103. Synedra fulgens. 238 a!’ & al". Gomphonema acumi-
105. Nitzschia Amphioxys. natum, var. y.

108. Nitzschia Sigma. 239. Gomphonema cristatum.
109. Nitzschia obtusa. 241. Gomphonema intricatum.
110. Nitzschia linearis. 243. Gomphonema tenellum.
112. Nitzschia dubia. 244. Gomphonema olivaceum.
114. Nitzschia plana. 245. Gomphonema curvatum.
115. Nitzschia scalaris. 246. Gomphonema marimum.
124. Amphiprora alata. 247. Epithemia longicornis.
130. Navicula serians. 248. Epithemia constricta.
131. Navicula cuspidata. 250. Cymbella affinis.

134. Navicula Jennerii. 259. Surirella subsalsa.

137. Navicula elegans. 260. Surirella angusta.

138. Navicula firma. 263. Synedra hamata.

147. Navicula Amphisbeena. 265. Synedra Gallionu, & /.
147. Navicula Amphisbeena, var. 6. | 266. Nitzschia Brébissonii.
148. Navicula spherophora. 267. Nitzschia vivax.

149. Navicula ambigua. | 270. Amphiprora vitrea.

151. Navicula punctulata. |

152. Navicula elliptica. The following are mounted as Test
154. Navicula didyma. Objects.

165. Pinnularia oblonga.

168. Pinnularia alpina. | 104. Nitzschia sigmoidea.

171. Pinnularia acuta. | 118. Nitzschia lanceolata.

173. Pinnularia radiosa. 129. Navicula rhomboides.
176. Pinnularia cyprinus. 199. Pleurosigma elongatum.
178. Pinnularia stauroneiformis. 200. Pleurosigma intermedium.
185. Stauroneis Phcenicenteron. 201. Pleurosigma Nubecula.
186. Stauroneis gracilis. 202. Pleurosigma delicatulum.
194. Stauroneis pulchella. 204. Pleurosigma quadratum.
195. Pleurosigma formosum. 205. Pleurosigma angulatum.
203. Pleurosigma strigosum. 206. Pleurosigma obscurum.
207. Pleurosigma Balticun. 209. Pleurosigma acuminatum.
208. Pleurosigma strigilis. 211. Pleurosigma Fasciola.
216. Pleurosigma attenuatum. 214. Pleurosigma littorale.
219. Cocconema lanceolatum. 215. Pleurosigma Hippocampus.
221. Cocconema cistula. 216. Pleurosigma attenuatum.
222. Cocconema parvum. | 217. Pleurosigma lacustre.
223. Doryphora Boecku. | 275. Pleurosigma macrum.

235. Gomphonema geminatun.

For other Objects, Microscopes, Xe. see Catalogue.

6 COLEMAN StrREET, March 1853.

BPITHEMIA. > lst

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CATALOGUE

OF

ACHROMATIC MICROSCOPES, &c.

MANUFACTURED BY

SMITH AND BECK,

TO WHOM THE COUNCIL MEDAL OF THE GREAT EXHIBITION OF 1851 was
AWARDED ‘‘ FOR THE EXCELLENCE OF THEIR MICROSCOPES,”

6, COLEMAN STREET, LONDON,

Marcu 1853.

THEIR improved form of Stand, which is contrived for an easy and
most accurate mode of applying every kind of illummation, was shown
by them at the Great Exhibition of 1851, and is thus mentioned by
the Jury :—

“The Stand is excellent in principle; the body, stage, and appliances
beneath, are all carried on one stout bar, on the recommendation of Mr. G.
Jackson, by means of which the centring of the Achromatic illumination is
rendered easy and certain; and on any tremor being communicated to the
Instrument, it is equally distributed over the whole of the working parts.’
—(Reports of the Juries, pa. 266, Class X. No. 253.)

The increase of the Angle of Aperture, which 8. & B. have lately
effected in their Object-Glasses, is more especially worthy of notice in
the lower powers, which, adjusting through considerable thickness of
glass, or some depth into water, will, with a large aperture, exhibit
those objects which are the most frequent observation of the naturalist,
with a definition that a smaller angle of aperture cannot give. One of
these Object-Glasses, a #5ths (erroneously called “ half-inch” ), is thus
alluded to in the “ Reports of the Juries of the Great Exhibition”
(pa. 266, Class X. No. 253) :— ;

“The half-inch focus of 70° aperture is a wonderfully fine combination,
easily showing objects considered difficult for a one-eighth inch focal length
a little more than a year since, and bearing the application of the higher
eye-pieces in an unprecedented manner.”

LONDON: PRINTED BY TAYLOR AND FRANCIS,

RED LION COURT, FLEET STREET.

nn

Prices of Stands for Achromatic Microscopes, exclusive of Object-Glasses, ae
Apparatus and Cases, except where mentioned .........0..ceseceeeeeeeeeee 1
Microscope Cases, for No. 1 Instrument, No. 2, Nos. 3 & 4. .....0....000 2
Achromatic Object-Glasses for the Microscope ...........seeeseeeeeeersseees 3
Apparatus which applies to the cylindrical fitting under the stage of
No. 1 or No. 2 Microscope ...........0.ss0.-2- AA Eee coco deneinoasbacteponodso0- 3
Apparatus as applied to No. 3, No. 4 and No. 5 Microscopes .............. 4
Apparatus for Microscopes in general ............seseeeses cprhigcondosescacbasoc 4
Microscope bablesmrcecesetasestessesemescses nogsocecss6ed Sacsacedsstereondecemaaete 5
Microscope MaMps) w.ssccccscesncseseccessecrsetsecscceteceeeetossnsescrsereceemen 5
MAREE OO OOYRES _ coscaodooscaccéceosedonceuasceocscoctiboaccacponessactancsaco0e: 6

Cabinets for Objects, in which the Specimens lie flat, and with Porcelain

Mabelsi tothe Dra werswes.c.sceedsceceesaecisccotdctce ence ceeeteeceeenserescre 6
Instruments used in Preparing Objects <....2./.csccsesseves-roscceracescesonnes 7
Matenalsiusedans Mounting Objectsieccsseases-e-ceneeeesoneas-neeeeceseeeeeeeees 7
Woodward’s Table and Hydro-Oxygen Polariscope and Microscope ....... 8
Books ..... ROQnAROCORBOIDAnHatODOCONSUCAnOEsbodccHadHoGabogsoSnSnoceadboosDSS¢ocaticonSC 8
TElESCOPESH, sasccas fae sacsmes pleases cawstence sehen anensunnedeme cenecmcae ete naeee soeee 8
Spectaclesiand: Bye-olasses\.s..cse<s<+sederseecsenescucnsesenesesctracsaeseenssseee 9
StGLEOSCOPES 3 sc ccdseteacssuacesssetonsesscsneseesscouseuetee csc soete ee tenseeeonere ee 10
Drawing instruments, OcColecsceces score sc sten aesees Gnaceeeecetarconan saree scents 10

Barometers; (Chermometers,, &Cic. 0. scone sscc coed canencesespecesedeacensiaaaerss 10

Exclusive of Object-Glasses, Apparatus and Cases,

PRICES OF STANDS

FOR

EXCEPT WHERE MENTIONED.

ACHROMATIC MICROSCOPES,

[The construction of all these Microscopes is now so arranged, that
Smiru AND Beck can supply any apparatus without requiring the
Instrument for fitting. |

No. 1. Improved large Microscope, the limb continued

under the stage, and with cylindrical fittmg and
rackwork, for applying all illumimating apparatus
with ease and accuracy, mounted on two pillars
and cones, with revolving base to tripod; body
with quick and slow motions, graduated sliding
tube, and two eye-pieces; stage half inch thick,
with vertical and horizontal actions (given by rack-
work and screw, or lever), sliding and revolving
planes, and spring clamping piece; diaphragm
with revolving and removeable fittings ; large plane
and coneave murors, with lengthenmg arm, and
sliding on a triangular bar; pliers, jomt and for-
ceps, and two glass plates ....-..s.scesseeeeeseneeeeees

. Improved large Microscope, on exactly the same con-

struction, but made very portable ..........-..s.6. 33

. Improved smaller Microscope, on the same principle,

and with the same actions as No. 1, but with single
pillar, on tripod stand.....secseseesseeseeesseeeeeeeeaees

. Improved smaller Microscope, made portable .........
. Best Student’s Microscope, with uprights and jomts,

quick and slow motions to body, graduated sliding
tube, and two eye-pieces; thin stage, with vertical
and horizontal actions by rackwork, slidmg and
revolving planes, and spring clamping piece ;_ dia-
phragm with revolving and removeable fittings ;
double mirror, with lengthenmg arm ; pliers, for-

ceps, and two glass plates .......-.+++5006 “Areneepanosce 12
. Best Student’s Microscope, the same as No. 3, but

with plain stage, consisting of sliding piece and
clamping spring, one eye-piece, and single concave
mirror ..... La radalash dee wal teein apa sroned cn ulnwodeatesceldedileeees

£

bo
bo

25

18
DAI

=

Ss.

SS)

d.

0
0

2

No. 5, Smaller Student’s Microscope, with quick and slow
motions to body, one eye-piece, sliding tube, stage
the same as No. 4, revolving and removeable dia-
phragm, single concave mirror, pliers, forceps, one
glass plate, and mahogany Case .........ssseeeeeeeeeees

No. 6. Hospital Microscope, without joint, body with rack-
work motion, or sliding tube and slow motion, one
eye-piece, diaphragm, single mirror, and mahogany
PE) noc Adbnanee sou ste cud0Be Jbor chug ogonoy joa locas acoder at

No. 7. Travelling Microscope, quick and slow motions to
body, two eye-pieces, sliding tube, stage the same
principle as No. 4, revolving and removeable dia-
phragm, double muror, and “packed i ima Steet
case 10 inches by 43 inches and 3; inches deep ..

No. 8. Dissecting Achromatic Microscope, with quick mo-
tion and graduated sliding tube to body, stage the
same as No. 4, revolving and removeable dia-
phragm, single concave mirror, 3rds object-glass,
one eye-piece, erecting glasses and case; power from
5 tol OOimearsce....c) a. Beganodeas-0903 Scannrdaqnendegnes

No. 9. Darwin’s Improved Single Microscope, with one dou-
blet, three single, and three Coddington lenses,
dissecting apparatus complete, and packed in a
(CIE TS prt ap nasapdocdet6ca6 SoS NaGUC SCOP OE anocmasconaoenaant

MICROSCOPE CASES,

FOR NO. 1 INSTRUMENT.

Best Upright Case in Spanish mahogany, with box for ap-

PATALUS ....cereeeeeseseencecceceeeseneeeerenseseceeentesens
Best Upright Case, with twODOXES | cessecccssceeescteccsiese enaniais
Upright Case in Honduras mahogany, with box for appa-

Upright Case, with two boxes ....ssssssesssecceeeees seacnbncceee
Strong Flat Case in Spanish mahogany, with covered dove-
tails for the instrument when made portable ......

NO. 2.
Best Upright Case in Spanish acer with box for appa-

ratus. nooauoonde Betcaisieisiarstereieto aicluietaisle slelewieielenye rerio Baciesieteiteieine

TALUS... 2. seereccccerececccecesccensenseesseeeesccecesentenees
Strong Flat Case in Spanish mahogany, with covered dove-
tails for the instrument when made portable ......

nos. 3 & 4.

Best Upright Case in Spanish mahogany, with box for SERS
YAtUS .......e00ee coe eee cecccerececssssneneeeeeoeccnes seeeeeeee
Upright Case in Honduras mahogany, with box for appa-

5 10

3 10

Pe

2 2
1 15

oO coo SS)

SS)

3
Achromatic Object-Glasses for the Microscope.

Linear Magnifying Power nearly*. Anipletor Lieber.
fos With Eye-Pieces | @perture Price. aa
aan N°.1/N°.2(N°.3] Put tional.
7 Draw-tube closed | 20 | 45 | 86 Ma sd
g inch | Add for each inch 13 degrees| 3 0 0} 15s.

oftubedrawn out; 4] 6 8
5 Tube closed ...... 60 |105 | 180
3 inch | Add for each inch 27 degrees] 3 3 0} IIs.
of tube....... scboa|: (tf |) ta | AD
, Tube closed ...... 120 |210 | 350
{To inch | Add for each inch 55 degrees| 5 5 0} 10s.
OlstUDeseeracceets: 12} 20] 35
Ditto Ditto do. | do. | do. | 65 degrees; 6 6 0) 10s.
7 Tube closed ...... 240 |430 | 720
“5 inch | Add for each inch 85 degrees| 6 6 0
Ofjuu Demereaceeene: 30 | 45 | 80
Ditto Ditto do. | do. | do. |100 degrees) 7 7 0
Tube closed ...... 450 |760 |1300
+ inch | Add for each inch 100 degrees} 8 8 0
oftube..........| 40 | 60 | 115
Ditto Ditto do. | do. | do. |120 degrees 10 10 0

* With the $ inch object-glass and the erecting glasses, employing eye-pieces Nos. 1 and 2,
the magnifying power will range from 5 to 150.

APPARATUS
which applies to the cylindrical fitting under the stage of

No. 1 or No. 2 Microscope.
oo; 'SSaad:
Achromatic Condenser on an improved construction of two
powers, and revolving diaphragm, to give various
illuminating pencils from 80° to 25°, also stops for

the central rays, complete with adjustments ...... a 08-0
Achromatic Condenser without diaphragm, apertures 60° and

20°, brass work with adjustments ..........scscseeeeee 210° 0
Achromatic Condenser, Brasswork of, with adjustments...... 1 = 00%0

Wenham’s Parabolic Reflector, giving a dark field with an
object-glass of 100° of aperture, with adjusting stop
ANG fIEtINES ..2.-sceecevsesaunare eecee seoeeotenee editnanes 115 O
Amici’s Prism for oblique light, mounted on an improved
plan, with the reflecting surface uncovered for the
convenience of wiping ......... StedchePretoncnucdcenener 2a 20

4

£s. d.

Nachet’s Prism for oblique light, with accurate revolving

TGR SF eeclae isa oes ae eterna oe alate ate oe el aeeraree ie 121
Right angle Prism for reflecting the light more perfectly than

the muror, with adjustments and fittings to the tri-

angular mirror stem complete, and the reflecting

surface uncovered for the convenience of wiping... 2 10
Polarizing Apparatus, of two Nicol’s prisms and one selenite

film, with revolving fittmgs 0 “alllll eee Senterinee siect ole ee = 2 10
Darker’s Series of Selenites, which give 13 different colours

and their complementary tints, mounted on an 1m-

proved plan for their more accurate and easy ap-

jE C SRA Ens ASCAMOnOe: Cracrt GabearoAWceat concotipukaer cs 3 10
Darker’s Series of Selenites, adapted to the Selenite fitting

mentioned in “ Polarizing Apparatus”’............ Beary wulle® 7
Bundle of Thin Glass for polarizing by reflection or trans-

MISSION sic a eaeiheniSetelenioe de dsien doasestenasewetmeaeacene tess el
Black Glass for polamZing. ..4.25..40ssessseanasaaceedsesesenns devs 0 15
Dark Wells of three sizes, and holder ............csceeesceseeees 0 12

ener"

APPARATUS
AS APPLIED TO No. 3, No. 4 and No. 5 Microscopes.

Achromatic Condenser of two powers, 60° and 20° of aperture,
rackwork and complete adjustments to brasswork.. 3 0
Achromatic Condenser as above, with sliding fitting, and no

adjustments{0 DrASSWONK -..-+<.ondccwere rns) esecwalesls 2a
Achromatic Condenser, Lenses Of .........-.sssseccssessscoeecees 1 10
Wenham’s Parabolic Reflector, with slidmg stop, rackwork,

and complete adjustments to brasswork ............ 3 17
Wenham’s Parabolic Reflector, with plain sliding fittings ... 2 10
Nachet’s Prism for oblique light ............scsscsssscseeeererees 0 18
Polarizing Apparatus, of two Nicol’s prisms with revolving

fittings, and one selenite film...............ssseceeesees 2 10
Dark Wells of three sizes, and holder .................c0eeeseees 0 12

APPARATUS
FOR MICROSCOPES IN GENERAL.

Extra Eye-piece for No. 1 MichOScOpGe)-c-nece-aeeennsa eehtnecs 0 17
Extra Eye-piece for No. 2, 3,.4, or 5. Microscope .«..........:. 0 15
Extra Eye-piece for Hospital Microscope cpr ceponce fee conten 0 13
Indicator to Eye-piece ......-s:eccceesaceosentetcceseesececensoees 0 5
Micrometer, with Jackson’s adjusting screw and fittings to

Bye@=pleC@ resco: seenee+onmeseeqececeasqcceteacegecrnasder'eas 1.0
Micrometer for Stage, divided into 100ths and 1000ths of an

meh, and mounted in brass ..sssesssscesceesseseneseee 0 10
Micrometer for Stage, divided into 100ths and 1000ths of an

inch, mounted pe ere DRO BB COREE Hao ocuscutancoaee Oe

nace [or i=)

=)

ao oon i)

Co So i=) ocon

5

Wollaston’s Camera Lucida, with large field and fittimgs to
HYE-PleCe.. s0seccacasccceennagcacsseccssscocsensesessecceces
Erecting Glasses, with which, employing the two-thirds ‘inch
Object-glass and Eye- -pieces No. | and 2, the mag-

nifying power will range from 5 to 150 linear ......
Large Bull’s-eye Lens on stand......ccccessscecssenceresesencneees
Smaller Condensing Lens, with ball il socket fitting, to
apply to No. 1 or No. 2 Microscope .......+....+++e0e
Smaller Condensmg Lens, on stand, and complete move-
MENS ccccccccessccccccccsccccsessccscreccrescssctcecsccoens
Side Silver Reflector, with fittings to limb, or on a separate
SUAIGL Gacoseocqnqqdnasdoodepcoosapaucnonngasssoscaobeasoparec
Amici’s Prism for oblique light, mounted on a stand ....+. eee
Polarizing Apparatus, of two Nicol’s prisms with revolving
fittings, and one selenite film............--sseeseeceeees

Darker’s Series of Selenites, with stage and revolving fittings
Fwo Double Image Prisms and Selenite Film, with fittings

to Eye-piece and brass plate with holes .............
Crystals to show rings round the optic axis and fitted to

LRVGS DISSE), won 6 sSoopeongAsonspconaeMmBeesoAAs. each from
Movamrmalenes) sles staan sateen e heise escawsra ts thekesSocsaas from
Brooke’s Double Nose-piece .......02...sssceecestonccenscenseners
@ompressorumn cer seer ys see erates ence esbewas eb aseesesmene ceases
Wenham’s Compressorium for Parabolic Reflector ............
crew elven OX os attcreacssescesacdecrastitsoasensrctveceriener et ace
iDeives so ol Emr ib?s i Se aa asoremecconoccudeneocn ob iccoeeoreac secs oodsre
Small Plain Live Box ....0.202..0.0..0sesrsecsersecsnasousseccecesene
Large Glass Trough, with wedge and spring complete ......
Small Glass fr oughs scdulenpeidenielesiacciegisapeneevencetyslspeyss from
Net on three Glags Tnbes./.5.2...2m4023-3seasrasenseras sean ssercnnee
Glass Plates, with hollows and ledges...........0+-+0e+0++ from
Three-pronged Forceps and Joint.........scscccssscssenssooersons
Large Brass Pliers and smaller ditto...........- 0 5 O and

MICROSCOPE TABLES.

Handsome Walnut-wood Table, to revolve on carved pillar
and claw, with plate-glass top, and apparatus
packed im the drawers, as shown at the Exhibition

Walnut-wood Table, with improved revolving fittmg, on
handsome pillar and claw, with leather top .........

Tron Table with revolving top ........2c..scsscsseosesseseescesees

MICROSCOPE LAMPS.

Improved small Camphine Lamp, with glass cap, to prevent
evaporation of the spirit when Not in USE ....eeeeeee.
Best Argand Lamp, with blue chimney, for burning oil ......

Gas Lamps made to order.

25

bo

—_—

—_
NOW NAIDADWDANOOCOSO

Or bo

ARMRAHAOAAAAHRGOCSCS i=) oo a)S) i=) —) QS)

6
MICROSCOPIC OBJECTS.

[Persons living in the country can have series of Objects sent for selec-
tion, on giving a satisfactory town-reference and paying carriage both
ways. One week will be allowed for examination. |

Vegetable Preparations :— £ s. d.
Recent: Cells, Cuticles, Ducts, Fibre, Membrane,
Spores, Sporules, Tissues, Spiral and other Vessels,
Hairs, Leaves, Petals, Fungi, Sections of Woods,

SOE seeks ere scterlotaetesatstics lente eeae cterterciot each specimen 0 1 6
Fossil: Sections of various exogenous and endogenous
WOODS Aafia redteces cece dcncesonedonnes ace each section 0 1 6
Slides, with two and three sections...........- 0 3 O"and 0) 456
DesmidieverandvAl ee oe. cc.cctcoss eceesteerseescececnene each slide 0 1 6
Diatomacez :—Recent : Several hundred varieties, including
species of Campylodiscus, Cocconema, Epithemia,
Navicula, Surirella, Synedra, &e.— Fossil : Specimens
from various localities in the British Islands, Ger-
many, Italy, North America, the East and West
InvdiessNewsZealandeacccsmeecesseaecenceeeenecreatte coe) OG
Spicules and Gemmules of Sponges and Gorgonias ......... 0-16
Zoophytes; many ‘species’: :..c..cesceesacctsasdeeeateererennneee tees O a6
Shells, sections of various SPECIES caseercaescaneateneMecascaaecent OF IEG
Echinus Spines, sections in great variety .......cccseeeceseeeeees 0: 16
Entomological Preparations :
Antenne, Eyes, Feet, Hairs, Scales, Skins, Spiracles,
Stings, Stomachs, Tongues, Trachee, Wings, &c.
Specimens of numerous Acari and Parasites............ 0O- A 36
Hairs, Whiskers of various Animals mounted whole or in
section, Quills, Feathers of Birds, &¢. ..........sseeeeee MY uo
Objects from Human and other Bodies .........ss.sssseeeeenes O° EG
Anatomical Preparations :—
Blood-Discs, Pigment-Cells, Skin, Muscular Fibre, Tis-
SUES AOCOS Niwecc swede tains sla ccdenee eee ERR Recon eaee from O 1 6
Bones :—
Transverse and Vertical Sections of 60 or 70 Recent
and Fossil Mammals, Birds, Reptiles, and Fishes
Meche each slide 0 1 6
Transverse and Vertical Sections of about 30 varieties,
Recent:andgHossil 25... ..cessecsccecnsnaccoe tenes each 0 2 O
Injected *Preparutions ..cccsee.casaderesemecsedae menses eee from 0 2 6
Polariscope Objects, about 100, selected from Animal, Vege-
table, and Mineral Substgnces ........sesceeeeseess each O 1 6

Mineralogical :—
Sections of Limestones, Oolites, Flints, Agates, &e.
each from 0 1 6

an

CABINETS FOR OBJECTS,
in which the Specimens lie flat, and with Porcelain Labels to the

Drawers.

Best Spanish Mahogany Cabinet, with glass panel, and to
hold 1000jiobjects! 7 Acsenneannstteononsecercoesence se. 7 0
Honduras ditto, without glass panel.............scscscsseceeeees 6. (690

7

we, Sa 1d
Best Spanish Mahogany Cabinet, with glass panel, and to
hotdh7 oOhabyectsbenesee aec-s cancsteecuydocensoseenect ne 515 U
Honduras ditto, without glass panel ........sesssseeeseseeeeeeeees on Ons0
Best Spanish Mahogany “Cabinet, with glass panel, and to
Hold) SU ObyCetsiscerecscmsenesscecsadeoschotcnsinesongesmes 4. 4) ,0
Honduras ditto; without lass panel.....-.c2..scsce++4sssessseee< SP OM O
Cabinets made to any size, and of every description.
Cardboard Boxes, to hold two dozen objects .........++ exch, O 1 0
Ditto ditto one dozen) ditto) <..eessscesees 4, (0) O89
Ditto ditto half dozen ditto ..........2+00 0 0 6
Single Mahogany Racks, for objects .........essseeees per foot 0 0 6
Double ditto CittOvecssannussscaniencessceree a OO

Onn

INSTRUMENTS USED IN PREPARING OBJECTS.

Wood-cutting Machine with knife ............6 Seeiisestemeisenece I
Instrument for Cutting Circles of thin Glass ............000065 1s 0
Diamond for Writing or Cutting thin Glass...............20060 0-7, 6
Ditto for plate and window Glast 61890. ..2isrcsssecstele 012 0
Instrument for making Cells of gold-size or other fluids ae, “6
Page’s Wooden Forceps, for holding the glass slides when

Vip tao | oe AapondganaRSgaeadcicounes uso Lane Goasere EUoUaLEOaM 0 2 6
Small Buss Tables and Lamps for heating objects in mount-

HIVE hopabonboon seqdec asst ocbdecnopavopSesoescsnanedoaos from 010 6

Gueketts: Porceps tOmacep jars eetntet ce sen cecenecterconecte ce OO 7 6
Ironwork of Dredge, for deep-water fishing ...............+6- Ls 0
Small Collecting Bottles.................006 per doz. ls. 6d. to 0 3 O
Valentine’s Knife, for making sections of soft substances... 0 15 0
Small Dissecting Knives of various shapes ..........+008 each 0 3 0
Spring Scissors, 7s. 6d.; Curved ditto, 5s.; Straight ditto, 3s.
Needle Holders, 5s.; ES Hooks. 2s. 6d.; Points, 2s. 6d.
Cutting Forceps, 5s. "6d. ; Spring ditto, 3s.
Combination of three Lenses, mounted in Tortoiseshell, for

pocket hand! macnifiers: -.....<...coscoccsssaceosecasese 010 6
Ditto; withysmallibrassistands.ccsesnsscccecoeateeettacer otececeeeer 018 O
Coddington Lenses, in various mountings ........s00.0 fromi'0 6:76

DOO Onmnmnmrnwmw

MATERIALS USED IN MOUNTING OBJECTS.

Canada Balsam, Asphalt, Gold Size, Glycerine, &c., 1s. and 2s. bottles.

Thin Glass, in circles, 6s. per 0z.; in squares, 4s. peroz.; ditto, mixed, 5s.

Plate-glass Ships, 3 inches by | inch, with ground edges, Is. per dozen.

Glass Cells, square, round, oblong, oval, and with solid bottoms, 2s. 6d.
and 3s. per dozen.

Labels for covering objects, 3s. per hundred.

8

WOODWARD’S TABLE AND HYDRO-OXYGEN
POLARISCOPE AND MICROSCOPE. 3

Woodward’s Table Polariscope and Microscope, with polari-
zing bundle, black glass, silvered reflector, and
ground glass shade; large stage, with complete fit-
tings, and two powers with rackwork motions,
smaller stage for crystals; and box as stand, with
complete fittmgs for apparatus .........cseseeeeeeeeeee 10

The above fitted as a Hydro-Oxygen Apparatus, with lantern,
safety jet, bladders, and pressure boards; the Po-
lariscope and Microscope Condensers, and an eye-

lens to adapt to the lowest power.........+.+-+ extra 15
Clock for the Movement of Lime Cylinder ........-....-++++++ 4
ime @ylinGers! te sacasecesesancseeetiocccriese-cotnaane per dozen 0
Tourmalines for the above instrument ......eseeeseeeeeees from 1
Selenite objects Or GittO: yeessccacsaceseneeeeceewasecciessee: a oO

Glass, Quartz, and other Prisms; together with all matters
relating to Polarization.

PLLLPLPLPL LLP DADA

BOOKS.

Smith on the British Diatomaceze, Vol. 1............cseeeseeeees
Quekett on the Microscope, 2nd Edition............sceeeeeeeees
Quekett’s Lectures ‘on Histology ........0-.scsscscececsscecsoeees
Woodward on Polarized Light, 2nd Edition ............02++.
Wrythes on the Microscope) ....0-..is.scssceceseorerenseessnecenee
Hassall’s British Freshwater Algze, 2 vols. .........seseseseeees
Hassall’s Microscopic Anatomy of the Human Body .........
Microscopic Quarterly Journal ...........-...06- each number

SON NIC S'S =e

TELESCOPES.

1-foot Achromatic Telescope .....+-++ssssseeeeseeees A Btoscbanonces 1
20-inch Achromatic Telescope ......0s0..scsssesressessscsececenes 2
20-inch Achromatic Telescope, 2 drawers, leather body...... 3
20-inch Achromatic Telescope, 1 drawer, leather body ...... »
2-feet Achromatic Telescope, 3 drawers .........scseeeeereeeees 3
2-feet Achromatic Telescope, 8 drawers, portable ............ 4
2-feet Achromatic Telescope, 8 drawers, portable, on brass
tripod stand, in small mahogany case .........eseeeeeeeeee
30-inch Achromatic Telescope, 3 drawers ..........seeeeeeeees
30-inch Achromatic Telescope, 3 drawers, ou brass tripod
stand, in Mahogany CASE .........scoscoecssccssecnebereraeres
3-feet Achromatic Telescope ............0ssscccescscsscsescerscoees 6
3-feet Achromatic Telescope, on brass tripod stand in maho-
PANY CASE 02... cccccscecsoeceneresessrercassscaecaaescaseceeabes 10
3-feet Achromatic Telescope, | terrestrial and 1 astronomical
eye-piece, pillar and claw stand, and mahogany case ... 14

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ERY

33-feet Achromatic Telescope, with finder, 1 terrestrial and 4

astronomical eye-pieces, on brass pillar and claw stand,

with vertical and horizontal rack movements, and
steadying-rods, in mahogany CAaS€.......sesseeeeeeeeeren eens 40 0
Ditto on improved stand ..........ccrecocessosenceecssecersecescors 42 0
Mahogany stand for ditto and bolt ......sscecscsssecesseeveecers al
Universal Equatorial stand for ditto ........cesescseeeesenseneeees 30° 0
Varley’s Stand, mahogany with brass fittmgs ............+++4 12 12

Larger Telescopes, with every variety of mounting, made to order.

SPECTACLES AND EYE-GLASSES.

Gold Spectacles, double jomt ...... Spb0o0 fom 115 Oto 3
Gold Spectacles, single joint............+++ mn Ll Oro 3
Plated Spectacles?) s.c.-s-eterne--es-~aravecee aie LOMA,
GoldtHolderstesccaccsectccssecosnececeossenses ES Pil Wim 5
lated! Folders) cscccsessesesscoccceerstectess a % 0)

Goldi Hiyestramies ese acec-cdsceaentaacecsees oe 0 TON ORtow 2,
lated) Hy e-framen™ soccseqe<eeccessees sascer po Ole o
Silver Spectacles and Folders ............ a ee OR LO.

Pearl or Tortoiseshell and Gold Hand-

ATAMNES varices ccasinceedecreccaesemenscseciece ; Ag 4a. Ontono
Pearl or Tortoiseshell and Silver Hand-

AT AINIES, sean deemocieias Sees ooslceaisieeicleslce's omen end
French Tortoiseshell and Silver Hand-

TrAMES woiesce ce cstessacnewe caoaee segeseeee 5 Oily oO
Tortoiseshell Spectacles, double-joint .......s0...csceeeeeeseeees 0
Tortoiseshell Spectacles, single-joint ..........scesecseeseeeeeees 0
Tortoiseshell Folders.............csecceseees from 0 7 Oto O
Tortoiseshell Folders, with gold bridge .........e0e.sssscseeeees 1
Tortoiseshell Eye-glasses .............ss00 from 0 3 Oto 0
Fine Blue Steel Spectacles, double-joint ..................e000es 0
Fine Blue Steel Spectacles, smgle-jomt ............ eagadeen teat 0
Common Blue Steel Spectacles .......... fom 0 5 0
Spectacles, with tinted glasses ......... .. ee OI eeO
Horse-shoe Frames, with tinted glasses.. _,, i)
Railway, Spectacles:-..2.-sceosceccscserssuess sh ee ®)

New Glasses to Spectacles, CONVEX see....seeeceeeeecees per par 0

New Glasses to Spectacles, concave ¢...+2......s.0008 per par 0
Double for Brazilian Pebbles.

Spectacle Cases...... Antnnonoandabadesuchoqcsdbeckinasn aASqosns: from 0

Reading Glasses of every variety ......... from “0 37 Oto 2

Opera Glasses, Race Glasses, Horizon
PSHii(Sl] Olah, (oa oe Oa sancr ep Saeecaieocanaer 3 5 Wl Om 9

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10

STEREOSCOPES.
; ES
Best Spanish Mahogany Stereoscope on improved plan, with
BOL OL GINPENIIS) ep nesiceeatacesiecoessesusessseyesseeesscees 1
Satinwood Stereoscope, and Diagrams ..........ssscseceeeseseees 0
Mahogany Stereosecope, and Diagrams .........+++essessee Seeees: 0
Din Stereoscope, and Wragrams .-2....0..0.--csnscesransansaes ese 0
Photographic Viewsi@w Glass <..cssces----c0s0cen-sensseenes each 0
Dasuerreotypesi cc-scase=teneeeeces Sepeerans from. 077 “6 400
Talbotypes ......... Jenstenthaceesniuesedtorses a O42! 36) to. 0
Diagrams, &e. &e.
Spanish Mahogany Box to hold 2 stereoscopes and 24 slides 2
Spanish Mahogany Box to hold 1 stereoscope and 32 slides... 2
Spanish Mahogany Box to hold two dozen slides ............ 1

CASES FOR STEREOSCOPES AND SLIDES MADE TO ORDER.

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DRAWING INSTRUMENTS, &c.

Wollaston’s Camera Lucida, mounted .... from 110 Oto 3
Drawing Instruments for school use ........... sercap ares from 0
Ditto ditto IN WAHOLATY CAKE ....0>-sccnsereronaence 1
Ditto ditto in superior case, 3 ivory rules......... 3
Ditto ditto ditto in electruM ......+000.. 3
Ditto ditto ditto ditto double-jointed 6
GAM WOMAPASSES <ocere ss. caeecsncceoseceseteecees “se sedeces from 1
12-inch Ivory Plotting Scales ............ from 0 7 6to 1
12-inch Boxwood Plotting Scales, set of 3, with offsets...... 0
Ivory Folding Rules ...........ccecesssecssceseseccsereesncees from 0
Boxwood Folding Rules. .........sssceesssecesscesecssseses err iO
Plain Ebony Parallel Rules ... ..........ceceesesseeeeoseees ay ue)
Plain Rolling Ebony Parallel Rules...... qauasoaccguatanaes As eO.
Ivory-edged and graduated Parallel Rules .......... perinch 0

DIOL II

BAROMETERS, THERMOMETERS, &c.

Pediment Barometers ....--c-cceccescocscsccccesccsscesceses from 3
Pediment Barometer, best, with float gauge .......+sseeeeeeee 9
Wheel Barometers ........cccecsseesssscccscscscsceceveeeses from 2
Standard Thermometer .......cccccsescscesssescccecsccseces Pa 2
Negretti’s Maximum Thermometer ..-.......ecsseseeeeeeseeeeees 1
Six’s Self-registering Thermometer .......-0..cseeeseeeceeeeeeees ]
Horizontal Self-registermg Thermometer..........+.eseeeeeeeee 0
Boxwood Thermometers ......scsscscscecsscecscesceeeseeees from 0
Simmons’s Hygrometer ...scccsesecsecsecsscoseseccetessecesenecnces 2

RAIN GAUGES TO ORDER.

AIR-PUMPS AND ELECTRICAL MACHINES
TO ORDER.

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