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Of Boston, Mass

(Class of 1829.)

Received ved 24 Mee,

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Ach,

THE

mAY SOCIETY.

—

INSTITUTED MDCCCXLIV

LONDON.

MDCCCKLV.

ON THE

ALTERNATION OF GENERATIONS:

OR,

THE PROPAGATION AND DEVELOPMENT OF ANIMALS
THROUGH ALTERNATE GENERATIONS:

A PECULIAR FORM OF FOSTERING THE YOUNG IN THE LOWER CLASSES OF ANIMALS.

BY

JOH. JAPETUS SM. STEENSTRUP,

LECTURER IN THE ACADEMY OF SORO.

TRANSLATED FROM

THE GERMAN VERSION OF C. H. LORENZEN,

BY

GEORGE BUSK.

a
LONDON :

PRINTED FOR THE RAY SOCIETY.

MDCCCXLY,

NOTICE BY TRANSLATOR.

Tue object of this little work, and the mode in which
the subject is treated, are so fully exhibited in the
Author’s Preface, that it is scarcely necessary farther to
advert to them, excepting for the purpose of impressing
upon the reader, that he is not to expect m the account
here given of the phenomena intended to be comprised
under the term of ‘ Alternation of Generations,’ or ‘ Alter-
nating Generations,’ anything more than a mere outline
of the subject ; nor is it proposed by the author to be
more than the rough sketch of a picture, to the filling up
of which naturalists may, perhaps, be the sooner incited
to direct their attention, by learning from the ingenious
speculations here set forth the probable existence of such
a mode of development in some form or other, in most, if
not all, of the lower classes of animals. ‘ Chamisso’s Ob-
servations,’ published so far back as 1819, on the apparent
alternations of generation in the Sa/pe, may perhaps be
considered as affording the earliest glimpse of the subject.
The subsequent observations of Sars on the development
of the Meduse in 1828, and which were continued in
1835, 1837, and 1841, corroborated as they were in
great measure by those of Siebold in 1837; and the re-
searches of Lovén m 1837, on the development of Cam-
panularia, &ce., considerably enlarged the number of facts
relating to this mode of development. No one, however,

vi PREFACE.

appears to have entered upon the general question of the
existence of an analogous course of development ¢hrough-
out the lower classes of animals, until the author of the
present work, who was already favorably known among
naturalists by other publications. He has taken up the
subject with the view principally of tracing its general
connexion between the various classes. Whilst doing
this, however, he has made some very important and
highly interesting special observations on the development
of the trematode entozoa. In this he has undoubtedly
opened up a most extensive field for future inquiry; and
there is every reason, from what he states, for believing
that numerous and important additions will be made to
facts, serving for the foundation of a sufficient theory of
alternating generations, from investigations relating to
the multiform class of animals comprised under the en-
tozoa.

In the present work, owing to the paucity of the ma-
terials afforded by previous observations, the speculations
of the author may, at first sight, appear bold, and his
conclusions in some places hastily drawn; but, in many
respects, there must be conceded to them the character of
great ingenuity and considerable originality. Most of
the observations themselves are not brought forward as
new; but the attempt at giving these phenomena a natural
explanation, and at showing their mutual analogies, is,
to a great extent, as novel as the full elucidation of the
subject will be beneficial to the progress of invertebrate
zoology.

With respect to the use of several new terms in this
translation, the author’s apology will apply as well to
their use in this version as to their original adoption.

PREFACE. vu

The subject itself must be better understood before the
provisional terms now employed can be replaced by more
elegant or more correct expressions.

Allowance also for certain ambiguities of expression will
perhaps be made, when it is remembered that this is a
translation of a translation, and that the author’s meaning
may probably have suffered a little in each change of
language.

The imtroduction of the “ Anastatic” process for the
copying of plates, having appeared to be a highly de-
sirable object, if found applicable in some of the publica-
tions of the Ray Society, it has been tried on a small
scale in the present volume. ‘The two latter plates have
been copied from the original lithographs by this means,
and it is hoped that the figures will be found sufficiently
good for all their purposes; though it cannot perhaps be
said that the process by which they have been copied has
as yet arrived at the perfection which it is much to be
hoped it will ultimately attain.

G. B.

CONTENTS.

PAGE
Preface to the German Version : . ]
CHAPTER I.
The development of the Medusz es strobila, Meduse), tab. 1.
figs. 1 to 40 . : : + oil
CHAPTER II.
The development of the Claviform Polypes (Coryne, ee yne, Cory-
morpha, Campanularia,) tab. I. figs. 41-57 : 26

CHAPTER II.
The alternate generation of the Salpe (Proles gregata, Proles solitaria) 33

CHAPTER IV.
The development of the Zrematoda . : : : . 52
(a) Cercaria echinata ? (Siebold) tab. II. . 5 ‘ 8
(4) Cercaria armata (Siebold) tab. III. fig. 16 . > . 74
(c) Cercaria ephemera (Nitzsch), and Distoma duplicatum (Baer) . 87
(d) The development of other Trematode animals . wg
CHAPTER V.

Concluding remarks on the alternating generations and their real nature 105

EXPLANATION OF THE FIGURES.

Plate I, The development of the Medusa aurita : pally;
II, The development of the Fluke, Distoma pacifica : . 124
III, The development of the Distoma tarda : é . 128

Corrigendum.—p. 20, 1. 16, for generically divided, read of distinct sexes.

PREFACE

TO THE GERMAN VERSION.

GREATER publicity* is herewith given to an Essay,
the contents of which will, I hope, prove interesting, not
only to the professed naturalist, but to all of the generally
well informed, who may be led to the consideration of
the Harmonies of development in Nature. On whose
account also I have endeavoured (with what success the
kind reader may determme) so to arrange the exposition,
that the least possible impediment should stand in the
way of any one desirous of becoming acquainted with the
mode of natural development in question.

The special subject of this Essay is the fundamental
idea expressed by the words “ Alternation of Genera-
tions, or the remarkable, and till now inexplicable natural
phenomenon of an animal producing an offspring, which
at no time resembles its parent, but which, on the other
hand, itself brings forth a progeny, which returns in its
form and nature to the parent animal, so that the mater-
nal animal does not meet with its resemblance in its own
brood, but in its descendants of the second, third, or
fourth degree or generation; and this always takes place
in the different animals which exhibit the phenomenon,
in a determinate generation, or with the intervention of a
determinate number of generations. This remarkable

_* By the translation from Danish into German.

ts
ae
H

2 PREFACE TO THE

precedence of one or more generations, whose function it
is, as it were, to prepare the way for the later, succeeding
generation of animals destined to attain a higher degree
of perfection, and which are developed into the form of
the mother and propagate the species by means of ova,
can, I believe, be demonstrated in not a few mstances mm
the animal kingdom.

The first division of the lower animals, ın which I have
observed its existence, are the Meduse (Chap. 1) as they
have been exhibited to us in the observations of Sars
and Siebold, and especially of the former.

The polypiform animal Scyphistoma-Strobila, into which
the offspring from the ova of all the Medusze is meta-
morphosed, and which, though it does not itself become a
perfect Medusa, produces the /arve which do, is in my
opinion a precedent generation of the kind in question ;
and according to my own researches it resembles a polype
only externally, and is in its structure really a Medusa,
though one which is attached by means of a stem to fixed ob-
jects. So also in the claviform Polypes, Coryne (Chap. ID,
the so-termed polypehead is a precedent individual
which produces the more perfect and differently formed
medusa-like campanulate animals which are developed m
succession at the base of the clavate head, and the develop-
ment of which, varies very much in the different species,
before their separation from the preparative individual,
and their becommg competent to propagate the species
by ova, from which again proceed the Coryne or prepa-
rative individuals. In the Campanularia, which is nearly
allied to the Coryne, and in similar polypes, this relation
is also very mantfest, and in fact resides in an alternation
of at least three successive generations, which act
reciprocally in connexion with each other m the ad-
vancing of the species towards perfection. ‘The pheno-
menon appears in a striking light, especially in the
observations illustrated with figures, for which science
has been lately indebted to the Swedish naturalist S.
Lovén. ‘The three generations are disposed in a definite

GERMAN VERSION. 3

manner on a common polypidom and form a whole, or
colony which, as regards the welfare of the species, stands
in the same relation to it, that the hive of bees with its
colony of three differently-formed broods of young, does
to the bee species. It naturally follows that mention
should here be made of the mode of propagation of the
Salpe (Chap. III), (although indeed the observation of
the worthy Chamisso has been otherwise interpreted, but
im away of which science has not availed herself, how-
ever plausible the interpretation may have appeared to
the superficial reader ;) and thus we have an alternation of
generations, exhibited to us in the molluscous class, and
it is certainly not confined to the Sa/pe only, but extends
to all the compound Ascidians (Ascidie composite). In
the class Yntozoa my researches have sufficed to prove
not only the existence of such an “ alternation of Gene-
rations,’ but to show besides, that traces of a similar
mode of development are visible in almost al the divi-
sions of that class. According to recent observations it
is, however, exhibited most clearly in the Zrematoda
(Chap. IV), in which I prove that the Cercarie are the
larve of Distomata, and that they become true pupe ;
that the animals in which the Cercarie originate and
grow up are peculiar frematode individuals, descended in
the second or third generations from Distomata, and
consequently not produced directly from their ova, but
which, however anomalous they may at first sight appear,
constitute a precedent generation having for its object
the perfecting of the subsequent one.

To similar observations belong also the description
given long ago by Ehrenberg of the cyclical development
of the Vorticelle, and the already long-known though
misunderstood mode of propagation which obtains in the
Aphides.

The existence of an alternation of generations having
in this way been established, not generally only, but even
as it seems in all the lower classes, beyond doubt, it is

A PREFACE TO THE

proper to consider the relation which this kind of alterna-
tion bears to that with which we have hitherto been
acquainted, as taking place in the propagation of the
lower forms of animals; and this I have done in the last
Chapter (V) of the Essay. It appears to me very evi-
dent, that these preparative generations, a// of which have
this m common that they are mvariably produced from
ova, without being themselves oviparous, that they are all.
of the same sex, and all elimmate an offspring from the
germs contained within them, which offspring in course
of time becomes the animal from which the preparative
generation had derived its existence, and that all, as it
were, eliminate this progeny by their vital powers and
by means of their bodies ;* it is evident, I say, that these
generations represent in a lower degree what we have so
long admired in the gregarious insects, or those which
live in colonies, such as the 'l'ermites, Ants and Bees, &c.,
because the precedent, preparative generations, are, in
these instances, in consequence of the complete abortion
of the sexual organs, converted into preparative broods,
and the ‘‘ nursing” (ammen), which in the lower animals
is performed within or by the bodies of the “ nursing”
individuals, is for the same reason, in the above-named
class of insects performed differently, being in them
represented by a “ fostermg”’ of the young (Brutpflege)
to the performance of which duty the “ feeders” are
impelled by an artificial instinetf or conscious exertion of
the will, and of which they are rendered capable by the
peculiar formation of certain organs, at the expense of

* On which account I have termed these generations “ zursing generations”
(ammende), and the individuals of which they are constituted ‘ zurses” (am-
men). (‘Though the word “zurse” in English does not exactly correspond
with what the author intends to convey by the word “ amme” (a wet-nurse),
yet the translator has thought that the use of this short word, till a better
expression be devised, might be excused, not on the score certainly of its
elegance, but because it more nearly corresponds with the meaning of the
original than any other English word which suggests itself to him, and that
by making use of it a constant periphrasis is avoided. |

+ Kunsttrieb, the instinct to produce certain compound effects resembling
those of human art.

GERMAN VERSION. 5

the sexual apparatus ; so that the alternation of genera-
tions in this point of view becomes in its nature a neces-
sary or unavoidable step of the development, and we
may in the words of the great master, affirm, that “ Na-
ture pursues its course, and what we take for an exception
is in accordance with law.”

In what precedes, the object of the Essay, and the
modes in which the results at which I believe myself to
have arrived, have been obtained, will be sufficiently ap-
parent. The ‘alternation of generations” is, as has been
said, the fundamental idea followed throughout the book ;
I have wished to represent it in the reality which I am
convinced it possesses, from the researches of others as
well as from my own, however much it may have been
combated, in the one particular m which an ingenious
naturalist surmised its existence, even twenty years ago;
I have also been desirous of reviewing this phenomenon
and its real significance, so far as I have as yet observed
them in nature. With regard, however, to other points
which have come out during the course of these ob-
servations and researches, viz., that the Cercarie are larve
of entozoa, of the genus Distoma, and in fact of those
species which inhabit the interior of fresh water snails
(in the liver, &.); that the entozoa pass part of their
existence in a state of freedom in the water external to
the snail, which they afterwards inhabit, and that they
re-enter them from without;* ¢hat whole established
divisions of families of animals must be abolished, since
they include only undeveloped forms, or forms which
bear the same relation to the true and perfect form of the
species, that the “ workers” among ants and bees bear
to the fertile females of those sects ;+ and, finally, /Aat
several forms which have been considered as of different

_* Facts which I can now multiply from several other species besides those
which I have adduced.
+ This may doubtless be assumed of most, if not of all the genera of the
Coryne family, and of Siebold’s division of the “ Aseaual Trematoda,” &e. -

6 PREFACE TO THE

species and genera are seen to be stages in the develop-
ment of one and the same animal, &c. All these must
be considered as secondary results,—as facts which are
only adduced, so far as they serve to illustrate the fact of
the “ alternation of generations.”

In order to prevent my being further misunderstood,
as I have repeatedly been in my oral exposition of this
subject, and in the lately published Danish version of the
work, I must remark that the phenomena, upon which
my view of the alternation of generations rests, are, as
every naturalist knows, new only in part, but that they
have in this work received another, and, in my opinion, a
natural explanation. ‘They have generally been looked
upon as instances of metamorphoses or transformation,
the essential objection being overlooked, that a metamor-
phosis can only imply changes which occur in the same
individual; but when from it other individuals originate,
something more than a metamorphosis is concerned. ‘Thus,
it is quite erroneous to term a Scyphistoma the larval
condition of Medusa aurita, since a Scyphistoma never
becomes a medusa, but is the guas: mother of some scores
of them. Sars and Lovén have taken a more correct
view of the relation m which these creatures stand with
regard to each other, seeing in the development of the
Meduse and Campanularie a series of generations under-
going metamorphosis.

It is of the more essential importance that the distinc-
tion between an alternation of generation and a meta-
morphosis should be understood, because a metamor-
phosis may readily occur in one or other of the alternating
generations themselves, as we see, for example, in the
Distomata and Aphides. There is no transition from a
metamorphosis to an alternation of generations, and a
metamorphosis once commenced, cannot be continued
beyond the generation, nor from the living or dead indi-
vidual to another individual. I am not aware that any
one has published concerning the alternation of genera-

GERMAN VERSION. 7

tions of the Sa/pe, except those who have been disposed
to see something paradoxical m it. Professor Eschricht
has recently expressed himself upon it, and is of opinion,
that although in appearance it affords an instance of al-
ternating generations, yet that the whole may be more
readily explained by supposing a double mode of pro-
pagation in the solitary individuals ; that is to say, that
the Sa/pe in their younger state produce solitary young,
and at a later period those of the associated or catenated
form,—an opinion to which I have more particularly ad-
verted in the proper place.

In the class of Zntozoa, the Cercarie with their pupe
still remained a great enigma, although the opinion which
was at first entertained of their being equivocal animals
was I know wholly rejected; for their relation to the
animals “ nursing” them was very far from being under-
stood. ‘Sometimes they were considered to be necessary
parasites of the “ zwrses’’ who were unable to exist with-
out them, as they always contained them and died upon
losing them ; again, they were considered as embryos living
in a peculiar detached organ, which the “ zurses’”” were
supposed to be, and m consequence received the new
name of “ germ-sac” (Keimschlauch), being no longer re-
garded as independent creatures. With respect to the
remaining divisions of this class, I will now only refer to
the late views propounded by Professor Eschricht on the
cestoid worms, as to their being compound animals (axi-
malia composita) though not animals organically connected
into one whole, or belonging to two generations. ‘The
alternation of generations in the Aphides as a superfecun-
dation is sufficiently well known.

So much for the prevailing scientific notions with re-
gard to the relations which I have endeavoured to collect
under one fundamental idea.

I beg it may be observed that I have tried as much asI
could to collect scattered fragments into a whole, but that
I have always considered this only as the first loose intro-

8 PREFACE TO THE

duction to more extended labours in the same direction :——
labours which I had hoped to have seen entered upon by
others, whom this essay of mine might probably stimulate
to the undertaking. I believe that I have given only the
first rough outlines of a province of a great terra incognita
which lies unexplored before us, and the exploration of
which promises a return such as we can at present scarcely
appreciate. Several points of this continent have been
touched at by naturalists, who have there erected their
beacons usually without guessing that they were all in
the same region; the recognition of these visited points,
the discovery of a few new ones, and the tracing out of
their connexion with the adjoming coast line, so that the
connected figure of the continent might be more authori-
tatively laid down, is all that my researches claim. From
the beacons erected by my predecessors, I have endea-
voured to make a survey of the surrounding country, as
far as it was possible for one to do so; I have been
able to raise some of them to a greater height, in order
to take a more extended view from their summits; and I
have wished to render the general impression of the pe-
culiar aspect of the continent derived from these isolated
views as correctly as my conception of it would allow,
being persuaded that by so doing I threw a clearer light,
by means of this general picture, on the separate views of
the landscape, and perhaps was thus afforded the only
correct mode of viewing them.

I am well aware that many naturalists would not have
ventured upon such general views, such generalizations as
they are termed, as I have indulged in, partly in the
Danish version of this essay, and partly in an earlier
small work in an entirely opposite direction, and for
which I have been exposed, on several sides, to objections
and blame, on account of the dangerous consequences of
such speculations, and the tendency they have to mislead
others. I am, however, of opinion, that it would be a
gain to science, and is imperative upon every one to take
a survey of the field from the eminence on which he has

GERMAN VERSION. 9

instituted his inquiries, in order to observe how they may
harmonize with those instituted at an earlier period in
the same or in other fields, and that, together with
the observations themselves, he should give a general
view of those departments of Nature which he has been
able to inspect, and indeed in the colours in which he
believes he himself has seen them. By this method alone
does a collection of many facts become of value; but this
mode of generalizing is only of use when it assists in the
assimilation of observed facts. The one subjective view
follows the other, and is distinct from it: the one affords
to the half or wholly ascertained facts, which may be
compared to crude nutriment, a saliva; the other, bile or
pancreatic juice ; and in this way Science, which by means
of our periodicals had been oppressed and become dys-
peptic with too much raw food, is relieved from her
load.

With respect to the mode or way in which I should
wish my Essay to be read, I may be allowed to remark,
that the “ Explanation of the Plates” is so arranged that
it may be read through, while at the same time the plates
are looked over, so that before perusing the work itself
the reader may acquire a notion of its contents, and, if he
be not a professed naturalist, he will thus be much as-
sisted in his study of the subject.

In conclusion, I request indulgence for the terms which
I have been obliged to invent for the expression of new
ideas, which could not. otherwise be expressed in the
German or Danish language; they are, in fact, but few,
although their number will be increased should the views
I have sought to establish be confirmed.

I cannot flatter myself that the exposition might not in
several places have been much better given than it is, but
I have spared no pains in making it as clear as I could;
with respect to this, I have to thank my friend, the natu-
ralist J. Reinhardt, jun. not a little, who in the kindest
manner undertook the not inconsiderable labour of re-

10 PREFACE TO THE GERMAN VERSION.

vising the manuscript before it went to press, and by
whose revision it has been benefited in many places.

I now commend to the kind reader this Essay, which
indeed though presented to the greater German public as
a translation, I am desirous should be regarded as an
original work.

THE AUTHOR.

ALTERNATION OF GENERATIONS,
&c. &c.

CHAPTER 1.
THE DEVELOPMENT OF THE MEDUSA.

(ScYPHISTOMA-STROBILA, MEDUSE.)
Tab. I. figs. 1 to 40.

I presuppose that my readers are acquainted with the
animals vulgarly termed “ jelly-fishes” or “ sea-nettles,”
and in scientific language “ Meduse.”’ They are creatures
of a gelatinous consistence, very soft, and transparent as
glass, and are met with of various forms, discoid, hemi-
spherical, or bell-shaped, and they may be seen swimming
about immediately below the surface of the water, at sea
or in creeks, from spring till late in the autumn, but only
when the surface is tranquil and no rain has been falling.
They occur in vast numbers, especially where streams fall
into the sea or into a creek or bay, and they swim more
deeply in the water when the surface is rough, or after a
fall of rain, the slightest shower causing them to descend
rapidly. On the approach of winter they withdraw them-
selves to a greater depth, or probably nearly all die at
that period.

The circular border of the disc or bell of the Medusa is
sometimes entire, and continuous without any division,
and sometimes presents teeth, lobes, or frmges. This
condition, however, varies very much in different genera,
and, as we shall soon see, does so remarkably even in
individuals of the same species, according to their dif-

12 DEVELOPMENT OF

ferent degrees of development. The border of the dis-
coid or campanulate body of the Medusa is also frequently
furnished with extensible filaments or arms, of greater or
less length, which either depend loosely beneath the
animal, or twine themselves about from side to side in an
undulatory manner, and serve most probably for the pre-
hension of food (these are the so-called marginal tentacula
or filaments). In many species, however, these organs
are wanting. Similar filamentary appendages and fringes,
in several species, surround the mouth, and stomach,
which are placed in the middle of the bell-shaped, or
depend from the centre of the discoid body, and they
occur also in several situations on the under surface
of the animal.

Although the Meduse are usually observed to float
with the currents of water, still they are possessed of vo-
luntary motion, and perform a sort of rowing movement,
peculiar to certain forms among the lower animals; this
is effected by a powerful contraction of the body, by
which the water contained in its hollow is expelled; and
by such alternate contraction and dilatation of the bod
they are enabled to propel themselves with tolerable
rapidity.

With regard to the propagation of the Meduse, it had
been observed, that the larger and more common species
appear on our coasts and out at sea, in vast numbers at
certain seasons of the year, and also that m the spring
and beginning of summer the number of smaller or
younger individuals preponderated. From the latter
phenomenon, it might be concluded that the propagation
of these animals took place probably towards or in the
winter ; still (when we consider the fact of their complete
disappearance at that season) it could not occur in the
same localities in which they swarm in such great num-
bers durmg the warmer months. Moreover, it was not
known whether their propagation proceeded at the bottom
of the sea or towards the surface, or whether the young,
after birth, underwent a metamorphosis or not.

THE MEDUSA. 13

The Swedish naturalist, M. Sars, was the first who, by
his observations and researches, gradually removed the
obscurity which veiled the propagation and development
of the Meduse. No doubt had been entertained of this
bemg quite simple, that is to say, that it was not only
subjected to the general laws of development, but that
it was closely connected with the usual phenomena by
which those laws are attended. The development of two
species of Meduse—as it has been made known to us by
this observer, and as it has been confirmed in certain of
its stages by the observations of others, and especially
with regard to its first stage by the important observa-
tions of Siebold—presents highly remarkable phenomena,
which may truly be called peculiar, although they are not
fundamentally isolated. It is my direct object in the
followmg pages to endeavour to render this clear, and I
shall proceed, with all brevity, to make the reader
acquainted with this course of development, and select
as an example that of the Medusa aurita.

The full-grown Meduse which are met with in summer
and autumn are not hermaphrodite, as was formerly be-
heved, but of distinct sexes; some, consequently, are
male and others female. ‘The external form indeed of the
generative organs is the same in all, but their internal
structure and their object are entirely different, and it is
simply from the similarity in the outer form of these
organs that the erroneous notion has arisen, that herma-
phroditism exists not only in this, but m many other fami-
hes also. In the globular ova, while still in the ovaries,
young are developed, of an oval or cylindrico-oval form,
which, at a later period and after they have quitted the
ego, are collected into special receptacles, formed at the
same time in the four oval tentacles. In these recepta-
cles they remain for some time, for the purpose of being,
as it were, hatched in them, when they forsake the parent
and swim about in the water, as a swarm of distinct
creatures.

At this time they appear slightly compressed. laterally,

14 DEVELOPMENT OF

and one extremity is always thicker than the other. In-
ternally they present a cavity, corresponding in form with
the external shape. ‘Their movement in the water as
well as in the receptacles is effected only by means of
cilia, with which their whole external surface 1s covered
(figs. 1—5,) and they thus outwardly resemble, rather
the ciliated mfusoria, such as Leucophrys or Bursaria,
than a Medusa. But there is also, in structure and in
their manner of moving, a most essential difference be-
tween the young fry and the full-grown animal. But
since Meduse do proceed from this fry, resembling the
free swimming ones, it is evident, that some change must
take place either gradually or by a sudden transition
(metamorphosis, transformation.)

Let us now trace these young Meduse further. When
swimming, the larger extremity is always in advance,
which exhibits a depression (fig. 5,) and might readily
be supposed to be the anterior extremity, and the de-
pression in it to be an oral opening. But it will be
immediately observed, that the animal after a short time
attaches itself by this end to some fixed object (figs. 7, 8,)
and the above-described depression then appears as a _
sort of suctorial disc or organ of attachment which at the
same time secretes a viscous, tenacious fluid. The oppo-
site extremity then projects from the object to which the
animal has attached itself, and a real opening is formed
m it, whilst at the same time it becomes larger and more
club-shaped (figs. 8, 9.) The opening is at first very
small, but soon increases and its surrounding border
becomes flexible and moveable and assumes very various
forms ; in the contracted state it is quadrangular, and at
the four angles may be observed small protuberances,
(figs. 10, 11, 12,) which soon increase in length and
become slender, and finally, on the fifth or sixth day,
shoot out into four long tentacula or arms (figs. 13—15.)
At a later period, four other tentacula are formed between
these, which on the seventh day also appear as small
protuberances. Ten days after the little animals have

THE MEDUSA. 15

left the parent receptacles, they have all eight tentacula
(fig. 16,) and from three to five new ones begin to
appear, and the older ones when extended, have already
attained a length of from three to five times that of the
body (fig. 17.) In this way the number of these organs
continues to increase during the growth of the animal,
and new ones are constantly sprmging up in the inter-
spaces of the older ones, so that at length the number of
tentacula amounts to 24—28—30. From the size of a
small grain of sand the body becomes about a line in
length, and the original brownish colour passes gradually
through a reddish gray to a transparent grayish white.

In this fixed condition the animal in its external form
very much resembles a polype, but it now, although
unable to move about in the water, approaches the
Medusa form much nearer than when in the infusory
form it swam about by means of cilia.

This polypiform animal, which we shall afterwards con-
sider as a pedunculated Medusa, is affixed at the bottom of
the sea on various substances, as stones, or the shells of con-
chifera, but especially, as it would seem, on the stalks of the
large Laminarie. When the animal has obtained its full
number of arms or tentacula, or, as it may be expressed,
has reached its full growth, but a short time elapses
before a new life commences in it. Transverse wrinkles
are formed around the body, which increases at the same
time considerably in size, especially in length, and thence
assumes a cylmdrical form. ‘These transverse wrinkles
appear at first towards the superior extremity and thence
gradually descend, retaining, however, always the same
distance from each other ; they are at first famtly marked,
and more like transverse lmes or rmgs surrounding the
body (figs. 20, 21 ;) by degrees, however, the wrinkles or
furrows become manifestly deeper and deeper, in the still
elongating body, and at the same time the superior
margin of the projecting portions which are separated by
the furrows, becomes more and more elevated and
presents eight distinct lobes or divisions, which are placed

16 DEVELOPMENT OF

exactly in the same line, one above the other in each
annular division, so that the series appears to form eight
longitudinal bands extending from end to end of the
body (fig. 22.) In proportion as the contractions be-
come deeper, the lobular portions acquire greater mobi-
lity, and at the same time an independent vitality, and it
seems that the animal is capable of division into as many
independent, cup-shaped bodies, as it formerly possessed
divisions. And, indeed, this finally takes place as we
shall now see.

The subsequent development consists in fact in this,
that the divided portions so often referred to, and which
are placed one upon and in the other like a pile of cups,
are actually separated one from the other, while at the
same time they are elevated one above the other by an
alternate motion of contraction and extension (fig. 23,)
their lobular appendages increasing in length at the same
time.

In consequence of the movements exerted by each
portion and by which the whole stem or pile acquires a
vermicular motion, the connexion between them is much
loosened, and at last completely dissolved. The separa-
tion commences with the upper ones, and close observa-
tion then shows that they are actually superimposed one
upon the other, like piled-up cups, and without the
existence of any organic connexion between them.

After the complete separation of the cup-shaped bodies
from each other, they swim about with the usual peri-
staltic motion of the Meduse, and resemble those animals
in every respect, and as is the case in them, a quadran-
gular extensible mouth depends from the centre of the
inferior concave surface; when this mouth is fully ex-
tended, the animal bears no inexact resemblance to an
umbrella or parasol. Occasionally the disc is reverted or
turned inside out, so that the upper surface becomes
concave, and the lower convex, and in this condition, on
superficial observation, the mouth would appear to project
perpendicularly from the dorsal or upper surface. Al-

THE MEDUSE. 17

though these animals, whose remarkable origin we have
just traced, must be considered as Meduse, still they
will be found to differ in many respects from the Meduse
whose offspring they are, (vid. figs. 29 and 25), especially
in the form of the border of the disc and of the prehen-
sile tentacles or marginal filaments attached to it; in the
extent of the vessels of the disc, and im the shape of the
stomach. But on contmuing to observe their growth,
we in a short time witness the disappearance of these
differences as they approach nearer and nearer to the
form and relations of the full-grown animal (figs. 25—30.)
During their growth, for instance, the eight segments or
separate lobes of the margin increase but very little in
size, whilst on the contrary the intervals between them
enlarge very much, and thus the lobes or segments be-
come gradually much depressed (fig. 29.) In the fissures
of the lobes, exactly at the point where the ocelli, as they
have been termed, or coloured specks are placed, as well
as in the middle of the interspaces between the lobes,
are seen, proceeding like rays from the middle of the disc,
canals, or vessels, which are connected with each other
towards the border of the disc by a set of circular or
annular vessels, arranged in small arches which ascend-
ing slightly from the extremities of the radiating canals
proceeding to the interspaces of the lobes towards
those going to the edge of the body form segments
of circles, smaller in proportion to the less size or age of
the animal (vid. figs. 27, 28, 29, and 31, 32, 33.) As
the arches and interspaces alter, certain organs begin to
appear on the external side of each arch, between it and
the edge of the disc. The formation of these organs
commences with the appearance of a vesicle with opaque
contents, at the middle of the arch, and similar vesicles
are afterwards formed successively on the sides of the
first one.

As the number of these vesicles increases, those first
formed become larger and gradually project from the
substance of the disc, at first as short protuberances and

18 DEVELOPMENT OF

afterwards as growing filaments, and in this way while
the interspaces continue to increase, the border of the
disc becomes furnished with long, pendent, prehensile
tentacles, which are very flexible and in continual motion
in all directions (fig. 30); and it is in this way that the
tentacles are formed. Simultaneously with the appear-
ance of these organs, the vessels of the disc become more
numerous, since from the arches or from the annular
canals formed by the arches, cecal vessels shoot out into
the substance of the disc, which increasing in length, inos-
culate with each other, and terminate in the radiating
canals which pass from the marginal corpuscles of the
lobes. (figs. 31—33.) At this period, the disc exter-
nally, exactly resembles the full-grown Medusa.

The mouth, which even in the youngest detached
animal allows of being greatly extended and _ protruded,
is quadrangular, and presents four extensible angles.
These angles grow more rapidly than the four-sided oral
tube, so that in the more advanced animals, the mouth
appears during the growth, to have been divided or split
into four lobes. The minute serratures which appear on
the edges of these lobes are the commencement of the
lobes and frmges which are observed on those organs in
the adult animal.

Our small Meduse, of about an inch in diameter, cor-
respond in their form, in all respects with those which
are fully grown; as they increase in size, the internal —
organs are developed, especially those destined for the
function of reproduction ; and their development is com-
pleted late in the summer, when the ova in the female
are fertilized, from which the infusoria-like fry proceeds,
which affixes itself, and assumes the polype form; whence
a new series of Medusa-larve, &c., and the whole of the
above-described development is repeated in the course of
the year.

After having considered the particular course of de-
velopment of these Meduse, (and of the Meduse in

THE MEDUSA. 19

general,) it will not be uninteresting to trace the history
of those researches which have thrown light upon this
obscure department, in the account of the development
of the lower animals. As already observed, we have, in
this respect—to thank chiefly, the Norwegian naturalist
M. Sars. In a short work ‘ Beyträge zur Naturge-
schichte der Seethiere, (Bergen, 1828,) this observer
described two remarkable animals, Scyphistoma, a polype
with a four-sided extensible mouth, and Strodéc/a which
resembles a pme cone, and is constituted of a series of
Acalephe or Meduse, placed one within the other. In
his later celebrated work, ‘ Beschreibung und Beobacht-
ungen einiger merkwurdigen oder neuen im Meere an der
bergenschen küste lebenden Thiere,’ (Bergen, 1835,) he
states, that the Scyphistoma is not a distinct animal, but
the younger state of the animal, which he had formerly
named S¢rodcla, and communicates particular observa-
tions on this subject, especially with regard to its growth,
and the development of the acalepha-like creature. He
gives also a description and figure of some free marine
animalculz, which must be referred to the genus Zrhyra
(Eschr.), and which he looked upon as the adult state of
S.robila. These observations contained a paradox, which
could scarcely be believed, yet no one ventured to deny
their truth; they were unparalleled as it would appear in
the course of nature, as known at that time. Ehrenberg,
in his well-known work ‘ Acalephen des rothen Meeres,’
explained the Strodila to be a Lucernaria, on the point of
undergoing transverse division. -

M. Sars continued his observations on these remark-
able forms, but from want of time, his researches met
with no attention at the meeting of naturalists at Prague,
on which account he published a series of preliminary
notices in ‘ Wiegman’s Archiv f. Naturg,’ (1837, mi
Jahrg., s. 436,) in which he stated, that having pursued
the. further development of the Strodila, he had discovered
that the free, acalephoid animalcule, were metamorphosed
into the commonest of our meduse (Medusa aurita,) and

20 DEVELOPMENT OF

consequently that the genus Strodila, which was in fact
only an early stage in the development of a known
animal, and probably also the whole genus Zphyra (Esch.)
should be abolished. 'The observations themselves with
the illustrative figures, although dating from March 1837,
were first published in ‘ Erichson’s Archiv,’ (184.1—ersten
Heft.) In them the development of the young Meduse
after their liberation from the egg was described, and
their gradual transformation into the polypoid form of
the Strobila proved, from independent observations made
in September and October 1839. In which year, long
after his treatise had been already designed, Sars re-
ceived the ‘ Beiträge zur Naturgeschichte der Wirbel-
losen Thiere,’ (Danzig, 1839) of Siebold, in which that
naturalist clearly proves the truth of the assertion made
by him in 1837, that the Meduse are generically divided,
and also describes the development of the ova of Oyanea
capillata, and the history of the infusoria-like fry pro-
ceeding from them, until it assumes the form of attached
eight-armed polyps.

Sir Graham Dalzell has at different times communi-
cated observations on the same subject (The Edinburgh
Philos. Jour., vol. xvii and xxi, extracted in Oken’s Isis,
1838); but these observations are not only filled with
matters of which he has taken a false view, but also
contam phenomena which he has misunderstood, and
they have consequently been of no utility in science until
now that other fundamental researches have allowed of
their being correctly explained.

What is particularly to be observed in the above de-
scription of the development of the Medusa aurita, and
what will scarcely have escaped the reader, is the remark-
able circumstance, that it is not the, at first, infusoria-
like creatures proceeding from the ova, which are trans-
formed into the perfect Meduse, but that each of them
passes into a polypiform creature (Scyphistoma-Strobila,)
the apparently detached portions of which after their

THE MEDUSA. 21

complete liberation, present themselves as free and inde-
pendent animals (Zphyra) of the Medusa family. In the
polypoid animal which as it were includes the series of
piled-up Medusa-larve, (if they may be correctly so called
which are a younger stage in the development of the
Meduse,) such an advance to the perfect form has never
been observed ; and that it should attain the same per-
fection that the larvee do, is, in consequence of the size it
has already attained and its relations, altogether impro-
bable ; that it might reach this goal by following another
course of development is so much the more improbable
as we see in the rest of organic nature, like pass only
into like.* What the nature of this creature consequently
may be, is a question now to be solved, but we require
to enable us to do this, in the first place, a precise know-
ledge of its structure. Sars declares that this polypiform
animal simply incloses an internal cavity of the same form
as the exterior of the body; it is closed superiorly by an
annular membrane, which is placed within the circle of
tentacles, and which can be so contracted as completely
to close the opening, or so expanded as to form one,
equal in size to the diameter of the body. This opening
im the annular membrane, which is the entrance into the
internal hollow of the bell-shaped body is termed by Sars
the oral orifice, but certainly erroneously so. Of internal
organs Sars has observed only four roundish prominent,
longitudinal ridges proceeding at equal distances from
each other, from the bottom of the bell to its border, and
the extremities of which, when they reach the annular
membrane at the mouth of the bell, appear like four small
round holes in it, (vid. Sars in Erichson’s Archiv, Ister
H. Tab. i, fig. 31.) But here I beg leave to add some
remarks and observations which I made during a long

* That they have the power of again affixing themselves, and that a new
series of medusa-larve should a second time be developed from them can be
the less supposed, since Sars has shown that even the youngest individuals
which have become detached, before the transverse wrinkling has taken

lace, can only under extreme necessity re-affix themselves, and then very
oosely ; and all of them are not able even to do this.

22 DEVELOPMENT OF

residence in Iceland in the spring of 1840, on some in-
dividuals in that stage of development which was origin-
ally named Scyphistoma by Sars, and which were appa-
rently of the same species as those observed by him, or
at least corresponded entirely with his description of their
external form (in his work of 1835.) The few specimens
referred to were taken outside the so-called battery near
Keikevig, and under rather unusual circumstances, for
they occurred at an inconsiderable depth affixed on the
internal surface of some Modiolus shells and not on alge.
This circumstance afforded me the advantage during the
time I kept them in fresh sea water, of being unimpeded
by the mucus with which the vessel m which they are
placed is immediately filled, when it contains some of the
plant also, and of bemg able to detach thin laminz of
the half-disintegrated shell with the animals adherent,
for the purpose of microscopic observation, without
disturbing or injuring them in the slightest degree. The
number of tentacula was 28—30. The usual form of
the body varied from that of an inverted cone, to a cup
or bell shape (fig. 35.) The mouth of the bell was sur-
rounded by an extraordinarily moveable lip or annular
membrane which passed round within the circlet of ten-
tacles, and allowed of such expansion that the mouth of
the bell could be rendered equal in size to the diameter
of the body; it was also capable of contracting so as to
close the bell completely and of bemg extended, so as to
equal the length of the tentacles, in which condition it
was always quadrangular. When the annular membrane
was extended in this way (fig. 40,) 1t could be readily per-
ceived that a vessel or rounded canal ran down each of
the four angles; that these four vessels were connected at
the border of the opening with a circular vessel; and that
they were also united at the base by another and
larger circular canal, which ran along the circle of
tentacula. Into this larger circular canal, and opposite
to the four longitudinal canals of the annular mem-
brane, the four ridges which were observed on the

THE MEDUSE. 23

inner surface of the bell, directly opened. Midway
between these four canals, under favorable circumstances
and with a good light might be observed some fine lines,
which I looked upon as smaller canals of the same kind.

During the first few days in which the animals were
under my observation, I perceived no other internal
organs; but at a later period, I observed at the bottom
of the cavity of the body, a four-sided projection (figs. 36
and 38,) in which there was a hollow, usually square.

Frequently, when the bell and the annular membrane
around its orifice were extended, I have seen this quad-
rangular organ which is toothed at the extremity, become
elongated and project as far as the orifice, being placed in
the middle of the cavity like the clapper of a bell. At
other times, when the body has been much depressed, so
as not to be more than a quarter of its usual height, and
has presented at its circumference, as it were, four lobes,
this organ has projected more than half its length from
the mouth of the bell (fig. 37;) on which account, I could
no longer in any way doubt, that it was really an oral
opening and cesophagus, such as we find in the Meduse,
as for mstance in the maternal animal, the Medusa aurita.
But besides this point of resemblance we actually find also
a vascular system, consistmg of annular canals, connected
by radiating vessels, and resembling that system of organs
in the full-grown animal, together with a number of ten-
tacula, which are produced gradually and in a definite
order, like the tentacula of the self-developing Meduse, in
a word we recognize in this apparently polypoid animal,
an actual Medusa, but which is fixed.

These polypiform Meduse thus enjoy a mode of de-
velopment peculiar to themselves before the period at
which Medusa-larve are formed in their abdomen (if such
a term may be here applied,) and there is no observation
to show that they undergo any further development after
the formation and detachment of the /arve ; on the con-
trary, it has been observed that when the larve approach
the complete term of their growth, the trunk or stem is
found without such polypoid animal upon it.

24 DEVELOPMENT OF

We must, consequently, as far as we at present know,
assume that the function of these individuals is fulfilled
when the larvee have reached a definite development, that
their whole existence has for its object the perfecting of a
series of beings of the same species, towards which they
stand in the relation of not simply a precedent prepara-
tive generation, or brood of feeders, but, inasmuch as they
nourish the begs intrusted to them, not by independent
and special acts, but dy their life and from their bodies,
m that of foster parents (ammende): and I shall, conse-
quently, in what I have to say afterwards, designate them
by the short name of Ammen (altrices, “ nurses’ or foster-
parents.)

Since, according to the observations of both Sars and
Siebold, only animals which have the power of affixing
themselves proceed from the ova of Medus, all of which
become in the way so often described, polypiform
“ nurses,’ which nourish the. Meduse-larve from their
bodies, a considerable anatomical and _ physiological
difference clearly exists between them, which are a// of
one sex, and the perfect Meduse which are of two sexes.
Here, however, we observe a great natural harmony;
since wherever we find the fostermg of a brood or fry to
be committed to special individuals, these are always of
one sex, and indeed females in whom the sexual organs of
germination remain in an undeveloped state, whilst in
consequence of this abortion in the development of these
parts, the instinct or riss serving for the preservation of
the species takes a peculiar direction.

This representation of their essential sexual relations
is not affected by the fact frequently observed by Sars,
that the “ nursmg” individuals increase by gemmation ;
in which mode of increase, something more probably can
be perceived than the immediate multiplication of the
nurses. *

* Thus it is very remarkable that every part of the body of the “nursing”
animals, without distinction, is capable of throwing out gemme. May not,
however, the objection be made, that an ovum might occasionally contain
several embryos, one of which has become developed at the expense of the

THE MEDUSA. 25

This mode of development it is true has been observed
only in Medusa aurita and Cyanea capillata, two of our
most common species of Medusa, in which the earlier
circumstances of development so entirely correspond, that
it cannot be determined whether any given zurse belongs
to one or the other; but in all probability a similar mode
of development occurs in all true Meduse. It is, how-
ever, sufficient for our present purpose that researches
have shown this mode of development to occur in certain
genera of the family.

But with respect to the relation of the periods of de-
velopment to the seasons of the year, it should be re-
marked, that it is m the latter months of summer that
we meet with Meduse containing mature ova; and that
the researches of Sars on the origin and affixing of
the fry, were made in September and October, whilst
the detachment of the Medusa-larv@ has been observed
in the spring months of March and April. In the
first half of summer, and until the beginning of July,
I found in the Atlantic, solitary, free swimming indi-
viduals of from 2 ” to 3-4 ”” in diameter. If to this
we add the general observation made before, that the
smaller specimens of Meduse are usually met with in
spring, and the larger in summer, we shall perceive that
the development of these animals, like that of the rest of
the organic world, is intimately connected with the peri-
odical motions of the globe.

others, which make good their individuality at a later period? May not
several of these gemme originate in the same brood, which has attached
itself to an individual already affixed a short time previously.

26 DEVELOPMENT OF

CHAPTER II.
THE DEVELOPMENT OF THE CLAVIFORM POLYPES.

(CORYNE, SYNCORYNE, ÜORYMORPHA, CAMPANULARIA.)
Tab. I. figs. 41 —57.

I Have perhaps occupied much time with the Me-
duse, but I have thought it necessary to do so in that
instance, where the facts present themselves in greater
abundance, in order that the basis upon which they are
established, and the deductions to be made from them,
might appear with all the distinctness which they seem
to me to possess. In this chapter, in which I am desirous
of proving the existence of a similar course of develop-
ment im another perhaps not less numerous family of
marine animals, I am unfortunately compelled to be more
brief. What I have been able to collect in this mstance,
will probably be regarded with respect to the object I
have in view, as very little; I think, however, that even
in this little, as m the sketch of a picture not yet filled
up, what the whole probably may be, will be not indis-
tinctly discerned, when the necessary parts belonging to
it, and as yet deficient, are supplied.

The creatures which I am now considering are the
claviform polypes (Coryne) and the forms allied to them.
These animals have afforded much ground for speculation
to naturalists, especially with regard to the real nature of
the bodies, at first tubercular and afterwards bell-shaped,
which arise at the base of the more or less clavate polype
head, (fig. 41.)

THE CLAVIFORM POLYPES. 27

Professor Ehrenberg was the first to view these bodies,
as distinct individuals and even as of distinct sexes. He
considered the club-shaped polype-head to be the male,
and the bell-shaped bodies, sessile or dependent at its
base, as females. This representation has since been ge-
nerally followed. I propose to alter it a little.

In April and May (1840) in Iceland, I frequently
observed on empty shells of Dalanı and other hard sub-
stances taken from the bottom of the sea, coryniform
animals (fig. 41) fully half an inch long, and consisting
of a slender, membranous stem, which supported a rather
slender polype head furnished with a few (5 or 6) ten-
tacula. From the base of this head, four bell-shaped
quadrangular bodies hung down; which being placed at
right angles to each other formed a cross, and together
with the erect central head, the whole bore a consider-
able external resemblance to a Fritillaria, and I entered
it consequently m my note-book, under the name of
Coryne fritillaria. 'These bell-shaped bodies, which I
do not hesitate to consider with Ehrenberg as individual
animals and not as organs, strikinglyresembled the figures
which Sars has given of those in Corymorpha nutans and
Lovén in Syncoryne Sarsii. They were four-sided and
the angles moderately acute. "The lower edge of the bell
was cut off obliquely, so that one edge was longer and
descended lower than the other or opposite and shortest
one. The longer edge was shghtly enlarged at its inferior
angle and furnished with a darkish-coloured knob-like
organ, the real nature of which we shall very shortly see.
At each of the four angles of the bell-shaped body, there
was situate near the edge a triangular reddish coloured
spot, which, agreeably to common usage, must probably be
considered subservient to vision. Around the mouth of
the bell was a rather wide annular membrane by which
it was partly closed.

From the bottom or arch of the concave body a four-
sided free stomach, ciliated at the end, hung down. The
bell-shaped body depended under the base of the polype

28 DEVELOPMENT OF

head, from a slender peduncle, and its motions were vigo-
rous during its contraction and extension, by which the
water was as it were pumped in and out, and at the same
time the annular membrane surrounding the mouth was
alternately drawn in and pushed out. After being
observed for a longer or shorter time, the fully-formed
and lively campanulate bodies became detached, and
swam about in the water as free Medusa-like creatures ;
and they lived thus for several hours in the sea water in
which they were kept; a few surviving to the end of the
day. Nevertheless I do not entertain the least doubt of
this separation being quite natural, and that it takes place
when the animal is in its natural condition at the bottom
of the sea ; partly for the reason, that they did not appear
to suffer in consequence of their bemg detached, since
after becoming so, their motions were more lively than
before, and those which were not detached from the polype
ceased to move after the lapse of the same time as the
others; and partly because in the same places whence I
had previously obtained specimens of my Coryne fritil-
laria from the bottom (viz. below Oerfarsey, an island in
the bay immediately off the town of Reikewig,) I met
with a Medusa-like animal near the surface of the water,
which I considered to be a full-grown, free, bell-shaped
Coryne precisely of the same species (figs. 43, 44, 45.)
These individuals so exactly corresponded, both in their
external form and internal configuration with those
animals, except in size, that I can adduce as the onl
difference, the presence of a lobate organ attached to the
longest angle. ‘This organ, which in the campanulate
body of the Coryne, is represented by a wart-lke protube-
rance, in these presented at its broader base, two lateral
lobes, and at its more slender extremity one smaller lobe,
which appeared to be cut off. It was at the same time
filled with cells or globules, and two very long marginal
filaments sprung from its base, which under a high
power appeared to be beset with minute vesicles arranged
nearly circularly.

THE CLAVIFORM POLYPES. 29

The movement of these animals was altogether similar
to that of the detached bell-shaped Coryne, that is, they
propelled themselves backwards by a rhythmical pumping
in and out of the water, whilst the long filaments hung
behind them, waving about in all directions. Since these
individuals allowed the course of the organs to be more
easily perceived, I will here also remark, that at each of
the four angles of the bell a very delicate vessel ran down
_very nearly to the extreme edge, beyond which I was
unable to follow it. 'The four external angles were of a
milk-white colour, and formed im a peculiar way. In
each of the larger cells, of which the white lines or edges
of each angle were constituted, was situate a very minute
globular cell, which lay half m and half out of the mem-
brane, (stinging organs ?) (fig. 46 ;) I discovered a similar
structure in a white lme which passed down from the
lower edge of the bell, and formed a ring, connecting the
other four lines together. The triangular ocelli resembled
those of the Coryne, but were larger. At some distance
from the longer edge, but otherwise perfectly parallel to
it, two slightly zigzag lines (canals a) proceeded down-
wards to the peculiarly formed, lobed organ.

An organ developed in such a peculiar and striking
manner, must necessarily have a definite and essential
object, and since it is developed at so late a period, and
is as it seems filled with globules or cells, I can only look
upon it as connected with generation.

What I am convinced of with respect to this mode of
generation, namely, that, at least in this species of Co-
ryne, the bell-shaped individuals detach themselves from
the club-shaped polype and swim about towards the .
surface of the water in the form of small Meduse, is no
more than what R. Wagner, Sars, and Lovén have con-
jectured, with regard to the form and rhythmical motion
of the bell-shaped bodies of other species of the family ;
and if my memory does not deceive me, Sars, either by
letter or orally, also communicated to me, that he last
year observed the detachment of the campanulate bodies.

30 DEVELOPMENT OF

Compare also, on this subject, R. Wagner’s researches
on Coryne aculeata, which were carried on in the Adri-
atic in the year 1832. (Isis 1833, p. 256, tab. x1.)
That the bell-shaped animal frequently produced ova, and
consequently are females, has long been remarked, for
which we may refer to Lovén’s excellent memoir on Syn-
coryne ramosa of Sars, in ‘Svenska Vetenskaps Akade-
miens Handlingar, (Aar 1836,) which also appeared in
¢ Wiegman’s Archiv für 1837,’ (s. 322, tab. vi,) and to
iR. Wagner s figure of Coryne vulgaris, in his ‘ Icones
Zootomic :’ (1841, tab. xxi, fig. xvi.)

Still more, however, do the conditions of Sars’ new
animal, Cory ymorphea nutans recall what is exhibited in my
Coryne fritillaria. In order to compare them, I have
placed Sars’ figure of the bell-shaped bodies of the
former, next to mine (fig. 47.) Sars expressly remarks,
that the four angles terminate in as many knobs, and that
one of these is always larger than the rest, and supports
a smaller rounded protuberance. In this description
will be easily recognized the lobated generative organ
present in the detached form of the animal.

The notion promulgated by Sars (Beskrivelser, s. 25,)
and referred to by Lovén (1. c. p. 322,) that the bell-
shaped body detaches itself and becomes a Coryne or club-
shaped Polype, and that the above-described tubercle at
one of the angles is lengthened into the stem of the
polype, will certainly be shared in by no one, and no
longer maintamed by Sars himself.

Any transformation of the bell-shaped into the clavate
form, or into a Coryne, | must consider as altogether im-
possible, from considerations of the structure of each,
and of the facts we have already obtained on the subject,
although a direct observation of a former period would
appear to show that it does occur.

O. F. Müller, ‘ Zool. Dan.’ (p. 3, Danish edition, p. 13,)
for instance, asserts, that the detached capsules are de-
veloped into new polypes. According to my opinion the
bell-shaped individuals are full-grown and fully-developed

THE CLAVIFORM POLYPES. a

animals, which are destined for the propagation of the
species, and that there are probably both males and
females among them. In Syncoryne ramosa, Sars (Loven,
l.c.,) and Coryne vulgaris (R. Wagner, Icones Zootomice,
l. c.,) the ova are seen to be formed in the bell-shaped
individuals while still attached to the polype; in Coryne
fritillaria, and probably in Corymorpha nutans Sars:
the ova are not formed until the bell-shaped animals have
become detached, and have acquired their perfect develop-
ment into the form of medusa-like creatures. Agreeably
to the conclusions at which I have’ arrived in the preceding
section, I see in the Coryne itself only a previous genera-
tion of preparative “‘ nurses,” which are so far asexual,
inasmuch as that their generative organs are not de-
veloped. |

I cannot here forbear remarking upon a Medusa pa-
pillata observed by Abildgaard near Heligoland, and
figured in ‘ Zool. Dan.’ (tab. cxl,) as being an acalephoid
animal exhibiting such a close similarity with the bell-
shaped bodies nourished by the Coryne, that one would
be readily inclined to look upon it as such. If this figure
be compared with that by Loven of the more globular
campanulate animals attached to Syncoryne Sarsii, Wieg-
mans Archiv, (1837, tab. vi, fig. 25,) the resemblance
will be found very striking.

Should future inquiry determine, what, however, I by
no means doubt, that the whole family of claviform
polypes in the genera Coryne, Syncoryne, Corymorpha, is
only a stage or generation in the development of forms,
which when perfect closely resemble Meduse without
it bemg possible to arrange them together, all these
genera as such must be abolished, since they include
forms or individuals, which do not represent the perfect
state of the species to which they belong. The more
perfect forms, however, notwithstanding their resemblance
to Medusz, must still occupy the systematic place of the
claviform Polypes or Coryn&, as animals closely allied to
Tubularia, Sertularia, &c.

32 DEVELOPMENT OF

For observations and researches on the genus Campa-
nularia which have enabled us to institute this compa-
rison, science is obliged especially to Rapp, Grant, Lister,
and Loven.

I will here, as briefly as possible, give the results of
the observations of the last-named Swedish naturalist,
but for the observations themselves, must refer to the
sources whence my abstract is drawn, namely the ‘ Kel.
Svenska Wetenskaps Akademiens Handlingar,’ (1835,) and
‘Wiegman’s Archiv. f. Naturg.,’ (1837, s. 249—262, tab.
vi,) whence I have taken the figures (48—58) given in
tab. I. of this work, which afford us a striking example of
cyclical development, and throw a clear light on all the
neighbouring families both above and below.

Fig. 48 represents a Campanularia geniculata or bell-
shaped Polype very slightly magnified. It is evident,
that the individuals, which, surrounded by cells or cups,
shaped like inverted cones or bells, constitute one of these
polypes, have cells of three kinds, each of which has a
determinate position. The most numerous are the smaller
cells (individuals) placed at the extremities of the stem
and branches (fig. 48 aa.) In the angles between the
branches and the stem are situated the axillary cells,
which are always longer and nearly twice as large, (fig.
48 66,) and upon these are placed the third kind of
cells which are globular (fig. 48 ce c,) and the smallest
of all. The relation between the three groups of indi-
viduals or cells differmg thus in form and position, be-
comes clear, only when the development of the whole
polype is traced, and a moderately high power employed
for the purpose. The minute vesicular individuals (fig.
48 cc and fig. 53 a and 4) which are placed upon the
larger and longer axillary cells, contain two, and rarely
three moderately large ova, which exhibit the essential
parts of an ovum, and the individuals in which they are
contained, are thus to be considered as, in reality,
females.

When the thin membrane of the ovum bursts asunder,

THE CLAVIFORM POLYPES. 33

there issues from it an oval somewhat elongated embryo,
(fig. 53 a, and 54,) the whole of whose surface is covered
with cilia, by which it is enabled to move about in the
water in all directions, whilst at the same time it con-
tracts and elongates its body, which is sometimes more
of an oval or even pear-shaped form, and sometimes longer
and attenuated posteriorly. Loven distinguished in this
embryo, an interior cavity, contaming an opaque fluid,
and circumscribed by two membranes, of which the
internal is opaque and the outer one as transparent as
glass. He was unable to discover any oral orifice, and it
is hardly probable that one should be formed at this
stage of development.

After swimming about freely for some time, the little
creature attaches itself to any large object, as the frond of
a fucus, becomes contracted, and assumes a circular
figure. The cilia cease to vibrate and the membrane
upon which they are situate forms a narrow, nearly trans-
parent border around the animal, in the centre of which
an opaque spot is visible, which is formed by the close
ageregation of the minute granules contained in the
fluid (fig. 55.) Over this opaque spot the surface becomes
slightly elevated into a rounded projection; this is the
commencement of a polype stem, which rises gradually
in a vertical direction from the circular, expanded disc,
the substance of which contracts at the same time, and
is divided into four lobes (fig. 56,) which, according to
Loven, are the first traces of the offsets most usually put
out from the stem of the polype. By the alternate ad-
vance and stopping of the growth, the circular con-
tractions are caused which give its annulated aspect to
the stem of the polype. Fig. 57 shows the stem at the
beginning of its growth; its internal cavity, filled with
the finely granular fluid which circulates within it (which
may not inappropriately be compared to a nutritious
matter or chyle,) rises in a conical or spherical form, dis-
tending its two containing membranes. ‘The convex
surface of the external membrane secretes a delicate epi-

34 DEVELOPMENT OF

dermis, which is at first very soft, but afterwards becomes
firmer and horny, and it is in this way that the external
horny sheath or tube around these polypes is formed ; and
at the same time the spherical extremity of the growing
stem from the afflux of the contained fluid is constantly
rising, and thus forms a new ring or circle of the sheath,
above those already formed. When the stem has attained
a certain growth, the motion of the granules contamed in
the fluid becomes more active and the distension greater,
and a so-called cell or cup is formed, which is m fact a
polype in a cell. The dilated part is so much expanded
as to become, as it were, annular, and it secretes from its
inferior surface a horny membrane which forms a parti-
tion between the cavity of the stem and that of the cell now
in process of formation.* This formation commences by
the gradual ascent of the annular portion, which, as it
increases in size, secretes a horny membrane from its
outer surface, and forms the wall of an inverted conical
cell. When this cell has attamed its full size (fig. 50) all
the soft parts recede from its walls, and form a column in
the centre; and it is at this time that the tentacula begin
to be formed and the oral orifice to appear (fig. 51.)
The animal now pushes against the flat covering or lid of
the cell, protrudes its tentacula, and becoming indepen-
dent, seizes its food which consists of Cyclops and other
small erxstacea ; and the nutritious particles, circulating in
the interior cavity (or so called intestinal tube), become
more abundant. This is followed by the shooting out of
one branch after another at regular distances from the
completely formed polype, which is effected by the inte-
rior soft substance (the intestinal tube) gradually accumu-
lating at certain parts of the sheath or tube, and causing
a rounded projection on it, which projection continues to
grow from the stem in the same way that the latter grew
from the discoid expansion on the fucus. As soon as the
branches have acquired a certain length, a cell or polype is

* It is probable that the so-called intestinal canal has never any con-
nexion with the cavities of the cells.

THE CLAVIFORM POLYPES. 35

developed at the extremity of each, exactly hke that at the
extremity of the stem, and which follows the same course
of development. In this way we witness the gradual
formation of all the individual cells (@ aaa a, fig. 48,)
of the first form, on the compound polype which originated
in one of the minute ciliated creatures.

When the cells and polypes of the branches are fully
formed, other cells, much larger and differently shaped,
spring up in the angles between the stem and branches
(fig. 48 5 6 6, and magnified fig. 52.) They are formed
exactly in the same way as those first described, but are
always nearly sessile and provided with an arched opercu-
lum, from which the softer annularly expanded, substance
does not shrink (fig. 52 ;) consequently the animal does
not complete its tentacula, nor protrude itself from the
cell, On the contrary, other and still more interesting
phenomena are exhibited; for new individuals are gene-
rated between the outer and inner membranes surround-
ing the so-called intestinal tube, upon which are now
formed small elevations (fig. 52 4,) at which the granules
of the interior fluid appear to be detained. ‘These pro-
jections increase in size and become rounded, and their
connexions with the intestinal tube more slender, though
never entirely destroyed. Zxternal to these vesicular pro-
jections, some perfectly spherical bodies are visible (fig. 52/)
of an opaque substance, but presenting a clear round spot
like an included vesicle (fig. 52 y) on their external side.
The globular bodies, two of which are placed on the exter-
nal aspect of each vesicular projection of the central tube,
are inclosed in a delicate transparent membrane (fig. 52 2)
on the outer side of which is a circlet of minute tubercles
(fig. 52 4.) During the continued development, which
always takes place from above downwards, so that its
successive steps may be observed in the series of vesicular
elevations ranged one above another, the uppermost trans-
parent sac with its contents approaches the operculum of
the axillary cell and breaks through it, without, however,
losing its connexion with the central tube. The succeeding

36 DEVELOPMENT OF

sacs then follow the same course, until the whole series
is exhausted, in consequence of which, the polype of the
axillary cell seems to shrink; but it is constantly again
covered with a flat operculum or membrane, which adheres
to the border of the cell, and surrounds the slender con-
nexions of the sacculi with the central tube. Meanwhile
the apparent sacculi open (fig. 53 4); and a circlet of about
twelve irregularly-toothed tentacula projects around the
opening, and it is now seen that the sacculi are in fact
globular individuals, in which four longitudinal vessels
proceeding from the base of the tentacula to the bottom
of the body, represent the four vessels met with in the
more fully-developed coryne.

Thus these globular individuals are completely developed
females, and the opaque globules contained in them, ova,
in which the clear spot is the germinal vesicle (vesicula
Purkinji.) When the embryo is fully developed, it rup-
tures the delicate membrane of the egg and escapes,
remains for some time within the parent animal, through
whose opening, however, it afterwards passes mto the
water, attaches itself to a fixed object, and becomes the
origin of a new compound polype, in which the same
process of development is repeated. The parent animal
dies off or withers, having fulfilled its function.

Upon reviewing this sketch, it can hardly be considered
to present an instance of metamorphosis, since it is not
the same individuals which in the course of time exhibit
various forms, but we see here also, a series of genera-
tions whose succession in a definite order is necessary to
the complete development of the species. The ciliated
embryos which, by their adhesion lay the foundation of
the polypes, originate only from ova, which are developed
in the females. These latter are generated between the
inner and outer tunic of the polype in the axillary cells,
which polypes may consequently be considered as the
“ nurses’ or foster-parents of the female individuals,
whilst they are themselves, on the contrary, derived from
a previous generation of polypes of a different form,

THE CLAVIFORM POLYPES. 37

which occupy the extremities of the branches, are of the
same shape as the polype of the stem, and must be re-
garded as of the same kind, although they appear to arise
from it by what is called gemmation.

Numerous observations already recorded justify us in
assuming that the account of the development of these
animals, displayed in the foregomg exposition, applies not
only to Campanularia, Plumularia, and other Tubularie,
but also to the Sertularie. But how far the aggregated
Coralline polypes may be explained in a similar way,
namely, by supposing them to be a colony of imperfectly
developed individuals, whose aggregation has for its ob-
ject the complete development of individuals of the same
species, must be determined by future inquiry.

38 ALTERNATE GENERATION

CHAPTER IH.

THE ALTERNATE GENERATION OF THE SALP#.

(PROLES GREGATA, PROLES SOLITARIA.)

In the preceding chapter it must certainly have
occurred to every one, that phenomena would also be
presented among the Mollusca, particularly in the Sa/pe,
analogous to those exhibited m the development of the
Meduse and Coryne. ‘These animals have attracted the
notice of all voyagers, by the extraordinary circumstance,
that numbers of individuals, 20, 40 or more, are united
into very long chains (Salpa chains) in a peculiar manner
and by means of special organs of attachment. All
the individual Sa/pe composing these chains, are of the
same form, and are opposed to each other in the same
direction; they move with great uniformity, and keep
as it were the same time, by which movement the whole
chain progresses in a serpentine manner, below the
smooth and tranquil surface of the water ; for, like other
gelatinous and transparent marine animals, they approach
the surface of the sea, only in fair and calm weather.
Besides the Salpe which are thus united in chains, there
are also other individuals which are not so joined, but
swim about separately. Some of these exhibit evident
traces of their having previously been united, since they
possess the organs by which they had been attached,
and their shape exactly resembles that of the associated
animals; but in others, all trace of their having been

OF THE SALP A. 39

formerly connected is absent. ‘Thus the Salve may be
divided into two classes, the associated and the solitary.

With regard to these strange creatures, Chamisso*
made the curious observation, that the solitary Salpe,
though never themselves forming parts of a chain, yet
always contain a progeny resembling those which do, and
that each separate embryo is linked together, like the in-
dividuals forming the Salpa chains, and very closely re-
sembles them in figure; but in the associated Sa/pe on the
contrary, he found young, resembling the solitary ones.
This was usually a single pedunculated foetus, situate in,
and attached to, the wall of the respiratory sac of the
parent animal, and resembling the solitary Sa/pe in its
shape. In only one associated Salpa (Salpa zonaria)
there were always found four such pedunculated distinct
embryos. Now, as examination of the free swimming
individuals, which presented marks of having been dis-
jomted from a chain, proved that these also contained
only solitary pedunculated embryos, Chamisso concluded
from his observations, that all solitary Salpe, produced
associated ones or chains ; and on the contrary, that all the
associated Salpe were parents of solitary ones, and these
again of the associated and so on.

The generations of the Salpe consequently, are alter-
nately solitary and associated, so that a Sa/pa mother, to
use Chamisso’s familiar expression, is not like its daughter
or its own mother, but resembles its sister, its grand-
daughter, and its grandmother. Against this theory of
the alternate generations of the Sale, its intelligent
author had many attacks to sustain, and the more so, on
account of the considerable difference which exists be-
tween individuals of the associated and solitary Salpe,
and because no example of such alternate generation was
known in the rest of nature. Thus it was no wonder,
that endeavours were made to subvert this theory, partly
by seeking to weaken the force of the observations upon

* Chamisso. De animalibus quibusdam e classe vermium Linneana. Fase. I.
de Salpa. Berolini, 1819, 4to.

40 ALTERNATE GENERATION

which the theory was founded, and partly by interpreting
them in another way.

The former was attempted especially by Meyen,* who
in his voyage round the world was so unlucky as not to
meet with a single solitary sa/pa containing a chain of
embryos, although, free swimming salpa-chains in many
places surrounded the ship in masses. He consequently
attempted to make good the assertion, that the free
swimming salpa-chains and the associated embryos, which
Chamisso had observed in the solitary Salpe, were to be
explamed in entirely different ways, and had no relation
to each other. His observations, which were without
doubt superficial, led him to conclude that the associa-
tion of the Sa/pe was a voluntary act, and that they had
the power of reuniting themselves, after having been once
separated.

The opposite course is followed by Prof. Dr. Eschricht,
in a copious memoir lately published in Copenhagen, in
which he industriously tries to give another explanation
of the phenomena: on which account we must subject his
labours to a strict examination. In the first twenty sec-
tions, he adduces numerous anatomical relations, and re-
views them with as much accuracy as the examination of
specimens preserved in spirit will allow, and in the twenty-
first and following sections comes to the question, the so-
lution of which is the true object of the essay, namely,
the real nature of the associated embryos and Salpa-chains.
The examination of Salpa cordiformis, a solitary Salpa,
and of Salpa zonaria, an associated one, led Eschricht to
the conclusion, which agrees with the views of Chamisso,
that every Salpa chain originates in the embryo (p. 378,)
and consequently is born in the associated form, because it
is certain that the catenation of several Sa/pe commences

* Meyen. Beiträge zur Zoologie, gesammelt auf einer Reise um die Erde,
Iste Abth., über die Salpen; Nova acta Acad. Ces. Leop. Car. natur. Curios.
tom. xvi, pars prior. 1832.

+ Anatomisk- physiologiske Undersögelser over Salperne, af Dr. F. Es-
chricht, in den Se ıriften der Königl. Dän. Ges. der Wissench., naturh. og
mathem. Abhandl. viii. 1841, p. 297-392, tab. 1, v.

OF THE SALPE. Al

in their embryo state, decause also, there is no reason
for assuming any other mode of association in the Salpe
than that which originates in the foetal state, and because
no certain observations tend to show, that the connexion
of these animals is ever restored after having been once
dissolved, the impossibility of which is evident from the
structure of the organs of adhesion, as figured by Prof.
Hschricht. For he found in his specimens of Salpa
zonaria, which. all presented indubitable marks of the
rupture of a previous union, the four pedunculate bodies,
which as it is known, eventually form four solitary em-
bryos, just as Chamisso, and more lately Quoy, Gaimard,
and others have found them, and besides this, he ob-
served in the case of the Salpa cordiformis, that each em-
bryo coxstituting the embryo chain, while still inclosed in
the body of the mother, presented distinct traces of younger
solitary embryos ; Chamisso’s observations, which bear all
the stamp of truth, are thus confirmed by those of several
others, as well as by the anatomical researches of Prof.
Eschricht, who, however, considers them as insufficient
for the foundation of such a theory as that of Chamisso
mentioned above, although that accurate observer himself
asserts, that he had traced the whole course of develop-
ment in one species, viz. in Salpa pinnata “ hac unica
in specie, fatemur nos integrum metamorphoseos cy-
clum, hiatu nullo, omnibus suis momentis absolutum
persecutos esse oculis.” (/.c. p. 10.) For Prof. Eschricht
objects, that it does not appear from Chamisso’s observa-
tions, that the associated Sa/pe produced from their
solitary congeners, continue throughout to produce only
solitary young ; it may be possible, that the associated
Salpe become detached after the birth of their first off-
spring; may lose their organs of attachment; may assume
the solitary form, and afterwards produce a later genera-
tion of (associated) embryos. And he goes on to observe
also, that it is not proved by Chamisso’s observations,
that the solitary Sa/pe which produce chains of embryos,
and are thus the parents of associated individuals, are

42 ALTERNATE GENERATION

identically the same solitary Sa/pe which had been pro-
duced by the associated ones. Thus, according to Prof.
Eschricht, they may be born in the associated form from
solitary parents, and after producing a solitary progeny,
may themselves become transformed into solitary Salpe,
and in this condition may produce young in the associated
form. As long as these objections are unanswered, it
would be prudent, according to Prof. Eschricht, to assume
another mode of explaining these extraordinary facts,
“and which would accord better with the general laws
of development,” and he ventures to propose for further
mquiry, the following theory of the propagation of the
Salpe :

“ The Salpe in their younger state produce solitary
embryos, and in their older, associated ones. They do
not necessarily undergo any metamorphosis ; the single
(solitary) embryos assume, while still within the mother,
their permanent form; but the embryos forming chains,
are slightly anomalous in figure owing to their union, and
this form afterwards changes into that which is perma-
nently retained.” It is vain, however, to look upon this
as a natural explanation ; and, even if some observations
of my own of analogous phenomena, and the information
afforded by the observations of others upon similar sub-
jects, had not led me to consider Chamisso’s theory as
not unnatural, still I should feel myself compelled in the
name of Nature, to protest against that of Eschricht, when
it demands to be considered a natural one, either abso-
lutely, or in comparison with that of Chamisso.

Eschricht has referred his theory to “‘ a closer examina-
tion ;” to which we will now subject it. “ When young,
the Salpe produce a solitary progeny, and when older,
an associated one.” This expression assumes in the first
place, that one and the same animal, at two different
times or periods of its life can produce young differing m
no slight degree in their organization. It is true, that
birds when young lay fewer and smaller eggs, and when
older more and larger ones; that probably certain rep-

OF THE SALPA. 43

tiles at one time bring forth eggs, whilst at another, the
shell of the egg is ruptured at an earlier period, and living
young are produced, &c. ; but notwithstanding this, the
young from the eggs and those which are born alive, en-
tirely correspond in their organization. In the humble-
bee and wasp, we also know, that larve are produced
from the first deposited eggs, which only attain a definite
and lower degree of development, whilst the larvee from
the ova which are deposited at a later period by the same
females, attain another and a higher stage; but so far as
we are at present acquainted with their nature the larve
from all the ova, are indebted for the degree of develop-
ment which they respectively atta, whether higher or
lower, only to the adventitious and extraneous care which
is devoted to them; and I believe it would be very difficult
to find in the whole of nature, anything analogous to that
which is supposed by Eschricht.* Inasmuch as that in
an organization in other respects similar, we must always
presume Zhat organization or state of development to be
the higher and more complete which exhibits the greatest
degree of independence, and the existence of which is
connected in the least degree with the coexistence of
another similar organization, and as in this respect a free
swimming form must be considered as more highly de-

* This first objection, which is not exactly the same with the only one
made by Professor Eschricht to his own theory, namely that the embryos
never resemble their mother, but that the young of a solitary salpa, in their
form, invariably resemble the associated, whilst those of an associated salpa
always assume the solitary form, loses none of its weight from the assumption
of Professor Eschricht, that the reason of the difference of form which exists
between the associated and the solitary salpa-embryos lies especially in their
connexion. For the circumstance that the individuals of the one generation
of embryos are connected by peculiarly developed organs, whilst, on the con-
trary, the other generation wants those organs and consists of unassociated
embryos, is much more essential than a slight difference between the two
generations, in the outlines of their external figure, and in the relative extent
of certain organs, which besides are common to them both. Still it by no
means follows, that the reason of the difference in form between the asso-
ciated and solitary salpe should exist simply in their connexion ; for there is
some common, internal, fundamental prmeiple concerned in the necessary
occurrence of such an interconnexion, and of the organization conducive to
it, which it would be vain to attempt to demonstrate with our present amount
of knowledge.

AA ALTERNATE GENERATION

veloped, than one which is fixed or not free in its move-
ments, so we are certainly justified in considering, that
the solitary Salpe are superior in their development to
the associated ; and this is even admitted by Eschricht,
when he allows, that though late, eventually the associated
is changed into the solitary form. But, in the second
‚place, this expression implies that an animal in its younger
and less developed condition, produces young more highly
developed than those produced by it when it is itself
older and has reached a higher stage of development; and
if the different generations or forms of the progeny are
now compared, not with each other, but both generations
with the parent animal, the above hypothesis will be
found also to imply, ¢iirdly, that a young animal produces
a progeny of a form and organization which is attamed
by itself, only at a later period, and that when it has
attained its full development, it should only be able to
produce young far inferior to itself, and which by pro-
gressive transformation alone, afterwards attain to the
degree of development of the former generation and of
the parent.* But the worst conclusion to which this

* In meeting the objection, which he himself has made to his own theory,
Professor Eschricht declares : “that it is certainly extraordinary that the fetus
while still within the mother, should present a form at which the mother itself
does not arrive till agterwards ; but the wonder will in a great measure be re-
moved, when it is remembered that the difference of form (described in Sect. 15,)
depends on the relations which the animal assumes in its connexion with the
others, and not on necessary gradations in the progress of its growth towards
completion, and it consequently possesses no analogy at all with what is termed
metamorphosis.” (At Formsforskjelligheden beroer paa Forholdene i Kjcede-
dannelsen, ikke paa nodrendige Gradationer i Uddannelsen, altsaa aldeles ikke
ere analoge med de saakaldte metamorphoser. I have here assumed the
words “ere analoge” to be an error of the press, and “ Formsforskjelligheden”
to be the subject of the proposition. But nevertheless the sense of the
passage is still obscure.—Germ. Trans.) Probably there is here some error
of the press or of expression, which prevents a clear apprehension of the
author’s meaning. I willingly grant him, however, in the meanwhile, that
in one respect no metamorphosis does occur; for I am convinced that the
associated salpe never become other than associated, and are never solitary.
But on the other hand, it appears to me that Professor Eschricht, who
maintains that the associated salpe assume in process of time, though /a/e,
the solitary form, will find it difficult to show that such a transformation is
brought about in any other way than by a sudden transition, that is by a
metamorphosis, from the circumstance that the associated sa/pe retain for so

OF THE SALPA. 45

hypothesis of Prof. Eschricht leads, in my opinion, still
remains. He confessedly assumes, “ that the embryos
forming the chain,” change at a later period from their
somewhat anomalous form into the permanent one, (that
is, into the form of the solitary,) and at the same time
he supposes, as he is compelled to do both by the obser-
vations of living nature of Chamisso and others, and by his
own anatomical researches, that they, while still in the
first or associated condition, produce embryos (the form
of which is here immaterial) and then, afterwards assume
another and permanent form. On the contrary, however,
I must, fourthly, object, that it is opposed to all natural
considerations, to all known natural phenomena, and to
all physiological principles, that an animal should be able
to propagate itself before it has attamed its perfect form
and development. Although Professor Eschricht may
assume, that the first three assertions of his hypothesis
are not contrary to nature, the last, at least, must be
considered so.

Having thus shown that the proposed explanation of
the phenomena attending the propagation of the Salpe,
from whatever side it is viewed, is not the less unnatural,
we return to Chamisso’s theory, which is founded upon
the observation, that the first generation of these animals
is solitary, and the second associated, or, in other words,
that all Salpa chains are produced from solitary Salpe,
and all solitary Salpe on the other hand, from the associ-
ated. This conclusion may at first sight appear extra-
ordinary ; I am, however, convinced that every attentive
reader will find something similar displayed in the two

long a time, and so characteristically, the form they possessed during fcetal
life. It can scarcely be imagined that the external and internal conditions,
tab. iv, fig. 18, of an animal of the size of the Salpa zonaria should be
changed without metamorphosis into those of the Salpa cordiformis (tab. 1.)
Thus, according to the hypothesis of Professor Eschricht, the full grown
solitary salpe must have a double origin, viz., partly as solitary from young
individuals, and partly as associated from older ones, and which at a later
period assume the solitary form; but this also appears very unnatural, that
what was at the beginning dissimilar, should afterwards be developed and
become similar.

46 ALTERNATE GENERATION

preceding sections, and especially in the phenomena
observed with regard to the propagation of Medusa
aurita. This free swimming Medusa always produces a
progeny which is polypiform, and destitute of the power
of locomotion, but which on the other hand after attaching
itself to various bodies at the bottom of the sea, brings
forth a progeny consisting of free swimming Meduse,
which never assume the polypoid form; and this alterna-
tion is constant. ‘The fact may be thus expressed: that
each second generation is affixed and polypoid, or that
the free swimming hemispherical Meduse always produce
a polypoid offsprmg, and that the polypoid Meduse are
always the parents of the free swimming hemispherical
ones, &c. I have consequently no hesitation in expressing
my belief, that the alternate generation of the Salpe, from
solitary and associated individuals, is to be explamed in the
same way as that of the Meduse, and that the first gene-
ration of these animals serves as a series of foster-parents,
whose object is, by their furthermg the development of
the second generation, to conduce to the perfection of the
species. I am, however, prepared to admit, that this
kind of explanation does not enlarge our knowledge with
regard to the propagation of the Sa/pe; I only think,
that the phenomena already known, will have a clearer
light thrown upon them from the analogy. Some doubt
even must still remain, on the circumstance whether the
solitary or the associated Salpe are the foster-parents.
In my opinion however, it is the solitary form rather
than the other which should be assumed to be that of the
“ nurses.’ *

* From a remark in Sar’s Memoir on the Meduse (Erichson’s Archiv,
1841, H.i, p. 29,) I perceive that that excellent observer has mstituted re-
searches on the development of the salpe, and promises to communicate
them at another opportunity (which it is much to be desired should occur
soon.) Although in the above place he does not state anything precise, with
regard to the result of his inquiries, yet we may gather from what he says
that Chamisso’s views and remarks are in the main correct. “ The salpe
correspond in this with the meduse, that it is not their Jarve which are de-
veloped into the perfect animal, but the progeny of the Zarve ; it is not the
individual, but the generation which is metamorphosed.”

OF THE SALPA. 47

The Salve have always been placed near the Ascidie,
and the more accurately the structure of both these
families is known, the more evident does their relation-
ship become.

For this knowledge, we are recently indebted to the
last memoir“ of Milne Edwards, on the compound Asei-
die, or those which are regularly grouped in large masses
or colonies, (Ascrdie composite.) This excellent natural-
ist has pointed out a peculiar circulation of the blood,
common to all the Ascidie, whether solitary (Ascidie
simplices,) or in small groups (4. sociales, M. Edw.,) or
closely aggregated and for the most part regularly
grouped in larger masses or colonies (4. composite;) and
a similar circulation has also been discovered in Pyrosoma
which may be considered a swimming colony of ascidi-
ans, and in the Salpe.t

What, however, the more justifies us in delaying a
moment with the compound ascidians before quitting the
consideration of the series of the animal kingdom, to

* Milne Edwards, Observations sur les Ascidies Composées des cötes de la
Manche, 1841. Avec planches, gr. Svo.

+ In this circulation the blood is carried from the heart, and back again to
it through the same vessels. The heart, which is always placed close to the
generative organs, and usually in the inferior part of the animal, is moderately
extended, contracts with an undulating motion, and propels the blood in the
same direction with the undulations; for instance, if these are directed from
below upwards, the blood ascends in a stream along the anterior surface of
the abdomen, within a wide thoracic or abdominal vessel, from which a
number of contiguous transverse canals proceed, which are connected by
numerous smaller longitudinal vessels, and form the four-sided vascular net-
work on the walls of the branchial sac. All the transverse canals open into
a large dorsal vessel, which receives thus all the blood which has passed
through the vessels of the branchial sac; but besides this some blood is also
received by it which has not passed through the respiratory organ, in conse-
quence of the great dorsal vessel bemg connected at each extremity with the
great thoracic or abdominal vessel, by two considerable annular vessels.
The blood returns downwards from the dorsal vessel through a canal lying
on the dorsal surface of the abdomen (dorsal canal) to the opposite end of
the heart. After the lapse of a few minutes the heart begins to undulate in
the contrary direction, which is necessarily followed by the blood; which
now flows upwards during the same space of time through the dorsal canal
and dorsal vessel, traverses the branchial sac, and passing through the great
abdominal vessel along the anterior surface of the nidemien again reaches the
heart. In this way the blood flows alternately in opposite directions, accord-
ing to the direction of the movements of the heart.

48 ALTERNATE GENERATION

which the Sa/pe belong, is their mode of propagation as
confirmed by the observations of Milne Edwards. Al-
though all the Ascidie are affixed, yet their young swim
about freely, and to this end their oval obtuse bodies are
provided with a special organ for swimming, or sort of
tail which they move about in the same way as tadpoles
and Cercarie. At all events, this appendage has been
observed in all the Ascidie which are aggregated in
smaller swarms, or which form larger colonies, in which
latter, the individuals are so closely connected together by
means of a common, gelatinous, or membranous substance
which surrounds them (enveloppe,) that one is inclmed to
consider them as immersed in it. In several allied genera,
moreover, we find more or fewer individuals of the same
form and size arranged in a very regular manner, 6, 8, 10,
such being grouped on each side of a straight line or
radiating around acommon central point, (as for mstance,
Botryllus,) and forming a hollow or pit common to all,
and to the construction of the sides of which all the
Ascidie fixed around the common centre contribute, and
in which are situated the anal and generative openings, so
that in consequence of this structure, the mature ova and
young ones must be collected in the hollow or pit before
they escape into the water. It is very probable, that the
young remain some time in this receptacle, in order as it
were to be hatched, before they swim about; at least,
great numbers of them are frequently retained in it.
That the progeny when it quits this receptacle, does so
in the form of caudate free swimming animalcule, was
observed as far back as 1828, by Audouin and Milne
Edwards, and independently of them, by Sars (Beskri-
velser og Jagttagelser, 1835,) and the observation is
confirmed by Dalyell, (The New Edinburgh Philos.
Journal, January 1839.) But for our first clear idea of
the complete development of these free swimming ani-
malcule in their earliest period, we are indebted to the
above-mentioned larger memoir by Milne Edwards, and
the observations made by him in 1834 and 1839. After

OF THE SALPA. 49

the hatching of the young fry, Milne Edwards observed
their development at periods of four hours, and has given
figures for each of these periods which represent the
changes undergone by the animal in the intervals.

The young animals, as it was correctly stated by Sars,
present externally a delicate, lax integument, hanging
round them in sacculated folds im consequence of the
retraction from it of the soft internal parts; which are
otherwise of the same shape as the external sacciform
case, only that there proceed from them anteriorly several
cylindrical prolongations, dilated at the end into a sort
of knob, by which they are in contact with the external
tegument, to which they are the more closely united, the
shorter the time since the escape of the embryo from the
ego. These organs, thus placed with considerable regu-
larity within the integument and around the anterior ex-
tremity, misled Sars into the supposition that it was not
a single embryo which was contained in the egg, but a
whole circle or star-shaped assemblage of them. Milne
Edwards, however, shows that these dilated extremities
serve as suctorial discs, which are employed by the
animal after it has swam about for some hours in the
water, to attach itself by to larger objects, in order to
become fixed like the parent animal. At this period a
change in the development begins to occur. The pro-
cesses, which support the suctorial discs, and the in-
terior caudal tube become absorbed, and the substance
of which they were composed gradually enters into that
composing the bulk of the soft parts, that it may be
formed into new organs ; and in about ten hours from the
time of its affixing itself, the animal is contracted into a
globular mass within the wide, dead, caudate integument.
In twenty hours, the situations of the future mouth and
heart become evident ; on the next day the oral orifice is
completed, and water begins to enter the respiratory sac;
on the third day the pulsation of the heart is observable,
and the outward form of an Ascidia recognizable, and
within a few days all the organs are formed, except those

50 ALTERNATE GENERATION

of generation, which are not distinct till the end of the
second week.

Excepting slight differences in the length of the in-
tervals m which the animal arrives at the various stages
of its development, the same mode of development takes
place in all the compound Aseidie, and in all of them
consequently, the progeny consists of solitary individuals,
which grow up into solitary Ascidie.

With regard to the mode in which the colonies are
formed, especially when they are composed of individuals
distributed in regular groups as in the genus Botryllus,
&c., the question, as it appears to me, has been far too
lightly treated by M. Edwards. For he has observed, that
among the Ascidie composite, and sociales, individuals
occur which propagate themselves by gemmation as it is
commonly termed, since from the lower end of the animal
peculiar processes arise, which gradually become irre-
gularly or dichotomously branched, whilst the enlarged
extremities of these branches are, at a later period, formed
into Ascidie. Since in this way from a single individual
several Ascidie may originate, M. Edwards supposes that
the colonies owe their origin to solitary individuals, which
have multiplied themselves by gemmation, and from
which new individuals successive gemmations again take
place until the whole number is formed, which we find
constituting a given mass or group. To this it may be
fairly objected, that although in the ascidian groups or co-
lonies, the separate individuals are able to multiply them-
selves by gemmation, and although it may be admitted as
m some degree analogous to this, that it is possible that
the solitary Ascidie, into which the caudate young pro-
duced from the egg of the aggregated Ascidie are changed,
may throw out similar gemme—(although, so far as I
know, this has not been observed)—still, individuals of
equal size and similar form, do not spring at one and the
same time from such gemmation, and still less, do groups
of individuals, arranged in a definite number around a
common centre or central line, as in Botryllus, &c.; which

OF THE SALPA. 51

latter mode of grouping is quite unintelligible and inex-
plicable under the hypothesis of M. Edwards.

It occurs to me that the regular grouping of indivi-
duals in Botryllus, &c., bears the greatest resemblance
with the catenation of the Sa/pe, and may best be com-
pared with it; and I consequently consider, until obser-
vation proves the contrary, this grouping to be a feetal
condition, and assume that the Bofry/ii are born in this
state of organic connexion. In accordance with this sup-
position, I am inclined to consider the solitary Ascidie,
whose development mto perfect animals has been so
beautifully shown by M. Edwards, to be the animals
which produce the aggregated ones, just as the solitary
Salpe bring forth Salpa-chains. It may be sufficient to
have expressed this opinion, since observations are wanting
to enable our advancing further in this direction than to
a probable hypothesis.

I now proceed to another class of the animal kingdom,
the Enrozoa, with respect to some of which I can rely
upon observations which will serve to illustrate some of
their relations, which have been hitherto obscure.

52 DEVELOPMENT OF

CHAPTER IV.

THE DEVELOPMENT OF THE TREMATODA.

Tue best known form of the numerous family of the
Trematoda is the fluke or Liverworm (Distoma hepaticum,)
an entozoon which inhabits the livers of sheep in parti-
cular situations, and, especially in wet years, causes much
sickness among those animals. Similar forms are met
with in almost all animals of the four higher classes, and
among the lower, the Mollusca are equally infested by
them.

It might almost be said, that in these classes every
species of animal is inhabited by its own fluke ; in several
animals also, several different species of these parasites
have been found, which inhabit either all the organs of
the animal indiscriminately, or are exclusively confined to
one, (Liver, Kidneys, Bladder,) or to a definite part of an
organ. Several of these Zrematoda, as we shall also see,
when young are not connected with any organ, but enjoy
the power of free locomotion in water externally to the
animal which in their future state as entozoa they infest.
In this condition they are provided with a locomotive
organ, usually a tail of moderate length, by the waving
movement of which the creature propels itself through the
water, like a tadpole, to which in its external form it is
not dissimilar, except that it is much smaller, and almost
microscopic. In this larval state, the Zrematoda are
known to naturalists under the generic name of Cercaria.

THE TREMATODA. 53

It was well known that this form was not a permanent
one, but we were ignorant of the changes which it under-
went. As I have been so fortunate as to trace these
changes, I will now detail them.

(z) CERCARIA ECHINATA? Siebold.
(Tab. ii.)

I cannot determine with certainty whether the Cercaria
which I have figured in tab. un, fig. 6, be really the C.
echinata of Siebold, or a very nearly allied species; I
however, think they are identical, from the description
given in Burdach’s ‘ Physiology,’ (2d edit. 1. s. 187.)

This species has of course the usual character of the
Cercarie ; a body formed entirely like that of a Distoma,
but which is prolonged posteriorly into a long, transversely
striated, extensible tail, not a vestige of which is presented
by the Distomata. They are found by thousands, and
frequently by millions in the water, in which two of our
largest fresh-water snails, Planorbis cornea and Limneus
stagnalis, have been kept. ‘The body is usually of a more
or less elongated oval form, which, however, it is constantly
changing, assuming, during the continual movement of
the animal, every outline, from the circular figure which
it has in the fully contracted state, to the linear figure
which it possesses when extended. During its various
contractions it is more or less evident that a shallow
circular depression exists at the anterior part of the animal,
which might almost be termed a neck, as it separates that
portion which is nearest the mouth from the rest of the
body. This depression or neck is partially overlapped by
a delicate overhanging collar, by which the head (if the
portion beyond the contraction and containing the mouth
may be so called) joms the depression. When the crea-
ture depresses its head close to the body, this collar stands
almost straight out from it, and when the animal in this
state is viewed laterally, the collar appears like a small
tubercle on each side; but when it turns itself, or is

54 DEVELOPMENT OF

turned round on its axis, it is then easily seen that the
collar is constituted by a fold or border of integument,
and that it descends rather lower on the abdominal than
on the dorsal aspect, and also that it is deeply incised in
the middle of its abdominal portion. The sharp border
of the collar is more or less regularly serrated, and the
small teeth formed by these serratures have given rise to
the name echinata applied to this species, under the sup-
position that it is the same with that of Siebold, and that
the above described organ may be designated as “ a cir-
clet constituted of blunt spmes around the mouth.”
Under sufficient illumination, and when the part is
slightly compressed between slips of glass, there may be
distinguished in the substance of the collar and within
the integument numerous spicule or spmes, which form
as it were in the collar a circle around the oral orifice.
These spmes are placed with their thicker ends towards
the mouth, alternately near it and further off, in two
concentric circles, and the opposite and smaller extremity
of each spine passes mto one of the teeth of the collar.
The position of the oral orifice, m consequence of the
various contractions of the body, seldom coincides with
the most anterior part of the animal, but is usually placed
somewhat below it on the abdominal surface; the margin
of the mouth can be so much protruded, as to appear like
a suctorial acetabulum surrounding the orifice. ‘There is
also a sort of pharynx, but it does not appear to be mus-
cular. A little behind the middle of the body, is seen a
rather larger sucker (the abdominal) which is somewhat
depressed in the centre, and the margin of which can be
expanded in various ways. Close to the root of the tail
is a transparent spot, surrounded by an abrupt dark
coloured border, and appearmg like an interior cavity
with contractile walls, it is in fact however, only the root
of the tail which is seen through the body. On the other
hand, close before this there is a much smaller circular
spot, which is an opening or pore. Of the internal organs
which are visible through the semitransparent integument,

THE TREMATODA. 55

one is especially remarkable, large and vesicular, which
commences close tothe edge of the collar, passes down-
wards as far as the abdominal acetabulum, and thence
sends down a branch on each side of it, almost straight
to the posterior border of the body. As this organ is
composed of vesicular sacculi which do not open into each
other, nor form any common canal, but on the contrary
appear to open into a cavity situated beneath them, I have
looked upon it as a liver. From the oral orifice a canal
may be seen passing to the anterior end of this organ,
but not to enter it; since this canal must be an cesopha-
gus, 1am compelled to assume that a stomach passes
under the liver-like organ, and is conformable to it. Other
winding organs, whose real nature is not yet clear to me,
descend on each side of the body; they are partly filled
with numerous very minute equal sized globules or cells.
I have only casually been able to trace their course up-
wards as far as the sucker ; whether they terminate here, or
whether it is that they form a canal, which under certain
conditions of illumination may be observed, as a trans-
parent slightly winding streak, between the branches of
the liver-like organ, and which appears to terminate in
the caudal cavity, I must leave undetermined. In the
upper part of their course they contain small globules,
and form as it were several reticulations, and also as it
appears constitute a rmg around the pharynx.

The tail is very long, being about the same length as
the body, to which it is attached in a very shallow depres-
sion. It is extremely moveable, contractile and extensible,
and presents on the sides alternate depressions. It is
formed of several membranes or tubes placed one within
the other, of which the outermost is a very transparent
epidermis, under which is a tolerably thick membrane
furnished with transverse muscular fibres or sirie, and
between each pair of these transverse fibres is placed a
globular vesicle which appears to be a mucous follicle or
gland; the innermost tube is opaque and of firmer con-
sistence, it contains the longitudinal muscular fibres, and

D6 DEVELOPMENT OF

is usually reticulated on the surface. Through the centre
of these tubes there passes a slightly narrower canal, which
becomes very small towards the extremity of the tail.

The existence of the same layers in the body itself of
the Cercaria, can easily be demonstrated; but the trans-
versely striated layer is here not so much developed.

The swimming movement of these Cercarie is very
characteristic; in performing it, the animal curves its
body together into a ball, by which the head is brought
near to the caudal extremity, and at the same time the
elongated tail strikes out right and left in innumerable
sigmoid flexures, so that sometimes it presents the appear-
ance of a figure 8 behind the animal. In this way they
may be seen swarming about the water snails in great
numbers. ‘The reason for their keeping chiefly in the
neighbourhood of these animals is self-evident on placing
a few snails in a glass of water containing a number of
the animaleule. After swimming about the snails for
some time, they affix themselves by means of their suck-
ers to the slimy integument of those animals; and all
their movements upon it are readily per ceived with a
good glass.

They frequently deed themselves, roll about in the
water in their peculiar way, then return and reaffix them-
selves and remain still, attached only by the sucker, and
extend both the anterior part of the body and the tail in
the same direction; in this position, from the great
number affixed at the same time, they give the snail a
sort of flocculent appearance. "This quietude ordinarily
lasts but a very short time; they soon begin to move
about with a leech-hke motion in all directions on the
surface of the snail; but after they have wandered about
in this way for a short time, as if to set themselves right,
they attach themselves again by the sucker, and remain
more quiet. On examining with a sufficient magnifying
power a portion of the skin of the snail with several of
the Cercarie adherent to it, it will be perceived, that all
the efforts of these creatures are directed to the inserting

THE TREMATODA. 57

of themselves deeper into the mucous integument, and to
the getting rid of the tail, which is no longer of any use
to them as an organ of locomotion.

For this purpose they contract the body into an. oval
form, and lash out the tail forcibly on both sides, upon
which the body is again slightly moved, whilst the tail is
kept still, but only that it may be again lashed about
with greater vehemence than before, when the body has
acquired a point d’appui for its further contraction, and
for the more strenuous movements of the tail. These
repeated efforts end at last in the casting off from the
body, of the tail, which becomes a lifeless and irregularly
contracted mass, and at the same time the tailless animal
itself assumes so completely the appearance of a Distoma
or fluke, that it could not fail of bemg recognized as be-
longing to that genus, in case it were met with in this
condition in the viscera of other animals. However it
undergoes a further remarkable transformation before it
becomes a Zrue entozoon in the common acceptation of the
word.

In various Cercarie a copious mucous secretion is ob-
servable on the surface of the body, even before the loss
of the tail, and this secretion apparently increases during
the efforts of the animal to cast off its appendage, and
especially during the strong contractions of the body.

As soon as the tail has been got rid of, the Cercarıa
begins, by extending and contracting itself, partly to
move about, but partly, and im fact chiefly to turn itself
as it were round and round in the same spot. By this
sort of movement it makes for itself a circular cavity
within the mucus, which gradually hardens, and forms a
tough, nearly transparent case around it. ‘This is the
noted pupa state of the Cercari@, observed first by
Nitzsch* and afterwards by Siebold. The tailless Cer-
carie lie concealed under their transparent case, which is
arched over them like a small, closely-shut watch-glass «

* Nitzsch. Beitrag zur Infusorienkunde, oder Naturbeschreibung der
Zercarien und Bacillarien. Halle, 1817.

58 DEVELOPMENT OF

(fig. 7.) This has inclined Siebold to doubt whether a
proper pupa case is formed. I think the animal really
casts a very delicate cuticle; and in this opinion I am
supported, chiefly by observing that after the assumption
of the pupa state all the internal organs are more dis-
tinctly seen; for instance, through many pupa cases, the
formation of which I have watched under the microscope,
the above-described circlet of spmes in the collar might
be readily seen, which before the pupa condition had
been assumed were distinguishable only with great diffi-
culty. The position of this circlet of spmes necessarily
varies very much according to the position and motions
of the animal within the pupa case. Compare the figures
7 a,b, c, the last of which represents a pupa under the
highest power of my microscope.

The number of pup@ which may be found assembled
on the cuticle, and especially on the mantle over the back
of the snail, is very remarkable ; and I have several times
observed the skin of these animals, in the greater part of
its extent, as thickly set with the pupee as is represented
at fig. 7d. It must, however, be remarked that this
pupa condition is also assumed before the eyes of the
observer, in water and on a slip of glass, without the ad-
dition of any of the mucus or other substance from the
snail, and it takes place likewise in the interior of the
snail (when Cercarı@ occur there in a way which we shall
soon see) in the water-chambers or reservoirs of water,
betweeen several of the organs of the snail, m which the
Cercarie are frequently obliged to swim, instead of in
the water external to the animal.

This was the extent of our knowledge as regarded
these creatures.

The expression of the helminthologist Siebold, that
“ what becomes of these pupa Cercarze is at present an
enigma,’ applies, as far as my knowledge of science ex-
tends, as well to these as to all the other species of Cer-
carie. I hasten, therefore, to solve the riddle. How
long they remain in the pupa state, I am unable to say

THE TREMATODA. 59

exactly; but that they do so for a long time, not many
weeks only, but for many months, I will hereafter prove.
I will here only state that the above observations on the
Cercarie and their pupe were made in the months of
July and August, and that during this time, even when I
met with individuals which had assumed the pupa state
at an earlier period, there could not be discovered the
slightest difference between the /arve taken from the
pupa cases, and those which had become pupe a short
time before, so that it might be supposed that a still
longer time was required before they would escape from
their cases. ‘The same conclusion resulted from observa-
tions repeated in September. .

The first sign I observed of the animal quitting its
pupa case was in January, in some snails which I col-
lected by degrees from a ditch, where in the autumn I
had remarked a great number of Cercarie. These snails
I had placed in vessels in a warm room. I had pre-
viously observed in various pupe that the larva contained
in them was a little changed ; for if I caused one of the
pupa cases to burst, by sudden compression between
glasses, a convoluted animalcule escaped from it, which
had the form of a Distoma (fig. 8 a,) with a very promi-
nent acetabulum under the abdomen, and a number of
pointed spines situated on the upper surface of the collar.
At first the creature gave but little sign of life, and bent
itself slightly on all sides, but afterwards stretched itself
straight out, and commenced very lively movements.
The figures 8 6, 8c, and 8d, exhibit this Distoma or
juke, as I observed it many times in the winter months,
either immediately beneath the skin or in the water pas-
sages near the skm in the Zimneus stagnalis, many hun-
dreds of which I kept in large vessels. Fig. 85 still
exhibits the circlet of spines, from which it would seem
the animal had but just escaped from the pupa case.
The fissure in the middle of the collar on its abdominal
aspect, and the spmes which in the neighbourhood of the
fissure cross each other, were very distinctly seen; at

60 DEVELOPMENT OF

the same time, I observed very clearly that the surface of
the abdomen was hollowed out in a broad line, extending
from the collar to the discoid acetabulum, between which
and the posterior end of the body I noticed in several
individuals a spot composed of transparent globules or
cells, within which again were two contiguous clear
specks, the whole of which I could only look upon as the
transparent ends of the forked intestine, surrounded by
the hepatic substance. The animals represented by
fig. 8c, 8d, are more advanced. In fig. 8 c, the spmes
had recently fallen off, leaving evident traces of their at-
tachments on the upper surface of the collar; fig. 8 d, on
the contrary, had lost all trace of the spines, and its collar
was much smaller. The abdominal acetabulum was also
smaller, and had lost its cup-like form. The liver-like
organ, and the czecal prolongations of the digestive cavity
surrounded by it, were in all these individuals of unusual
width.

Finally, figs. 8 e, and 8 f represent this fluke as I
met with it, to the number of 10—12 individuals in the
liver of some snails (Zimneus stagnalis,) on the 6th of
August, 1841. These snails had been taken in a place
much exposed to the sun, at a sea sluice near Gräse.

The Distomata differed from those described above,
which I afterwards found beneath the skin of the snails,
especially in their greater sluggishness of motion and the
more homogeneous, parenchymatous consistence of the
substance composing the body. No external trace of
longitudinal or transverse muscular fibres was visible,
although the individuals figured in 8 ¢ and 8 d, pre-
sented distinct and regular transverse ruge, and performed
very lively movements during their contractions.

Thus, the deeper these creatures had penetrated mto
the body of the snail, and into the substance of the indi-
vidual organs, the more of their own organization did they
appear to lose. Both the oral and abdominal acetabula
became proportionably smaller, although from the situa-
tion of the animal it was not possible that their size should

THE TREMATODA. 61

have allowed of alteration by contraction and expansion.
The digestive organs occupied their usual position ; but
through the integument they appeared only like a uni-
formly coloured, structureless material fillmg a forked
cavity, at the upper end of which might be observed a
pore, surrounded with a distinct border. The organs
containing globules, situated on each side of the middle
line, could at this time be traced upwards towards the
mouth, only for about half their length.

We have now seen, that the Cercaria echinata 1s de-
veloped into an actual fluke or Distoma. When I first
became acquainted with these remarkable creatures, I had
no doubt of the identity of the fwke, (fig. 8 e and fig.
8 f,) with the Cercaria echinata (fig. 6 ;) but it was not
till the last winter that I met with individuals which
having just quitted the pupa cases, were about to pene-
trate mto the body or glandular organs of the snail
(fig. Sadcd). Those in the condition represented in
(fig. 8 e and /,) occurred only in the liver, and indeed in
that portion which occupied the outermost whorls of the
shell.

The further advance of this fluke to a fully developed
animal, as we know it, may perhaps be determined from
consideration of the other Distomata and Monostomata,
in which the first stage of development has been shown
by the observations of Siebold and others. Our present
information would lead us to conclude that it deposits ova,
from which, either withm the maternal body or without
it, oval-shaped young proceed, which move about briskly
in the fluid contained in the interior of the snail, or in
the surrounding water, and bear no resemblance to their
parent. In what way this progeny is transformed into a
Jluke, or as we now know into a Cercaria, is as yet an
unexplained mystery ; but that this change can and does
take place throughout, only by the intervention of several
generations, may be assumed as beyond doubt ; and if we
examine attentively what is taught us by Bojanus, Baer,
and Siebold, respecting the development of the Cercarie,

62 DEVELOPMENT OF

and interpret the phenomena thus presented in a natural
way, we may to a certain extent penetrate the obscurity
which involves the solution of this enigma, although we
shall not arrive at its complete elucidation.

Thus if we are desirous of tracing the whole series of
development in this species of fluke, in the absence of all
observations upon its ova and their progeny, we can only
recur to their earlier stages of development, and try
whether we cannot trace them up to the egg, or at least
as near as may be to that point.

Whence comes then the free swimming Cercaria, after-
wards a pupa, vit. the Cercaria echinata ?

This question is answered by the observations of Boja-
nus, who states, that this species is the same with those
he saw swarming out from the “ king’s-yellow worms”
(“konigsgelben Wirmern’’) described by him, and which
occur in great numbers m the interior of snails, especially
of Limneus stagnalis and Paludina vivipara. It is, con-
sequently, m these yellow worms, which are about two
lines long, that the Cercarie which are the /arve of the
actual flukes are developed ; and since we now know that
the flukes are perfect animals, which themselves undergo
no transformation and are propagated by ova, we are
reduced to the conclusion that the progeny is indebted
for its origm and development to animals, which in
external form and partly in internal organization, differ
from the animals into which that progeny is afterwards
developed ; in other words it may be said, that we here
again meet with generations of “ zurses,” and that the
yellow cylindrical worms of Bojanus which inhabit the
snail, are the “nurses” of the Cercarie and Distomata.
That the Cercarie are actually developed in the above-
mentioned yellow worms, any one may be easily con-
vinced who will take a dozen large specimens of Zimneus
stagnalis from small stagnant pools which have been ex-
posed to the sun; the worms will be very readily found.
They are situated not so much in the viscera themselves,
(the liver.and reproductive organs,) as in the membranes

THE TREMATODA. 63

covering them, and their long bodies will be found half
floating as it were in the fluid, which occupies the space
between the organs and which appears to be pure water,
entering through the aqueducts or water-passages. Fig.
4 a represents two of these “ zurses’ a little magnified ;
their great difference from the Cercarie, and still more
from the /Zukes is very apparent. Fig. 4 a shows a
sunilar individual more highly magnified, and also slightly
compressed between slips of glass, which renders the vast
number of Cercarie within it more distinct. It is not
only the outlines of this brood of Cercarie, which are
seen in the “ nurses” thus. compressed, but several of
their internal organs as well, as for instance, the forked
intestine and the liver.

As regards the external form of these worms, it must
be allowed that it is usually alike in all, unless they have
suddenly contracted themselves, in consequence of some
external irritation, and owing to which contraction they
are sometimes scarcely recognizable from the alteration in
their shape. However, the number of these creatures
is so great, that they are crowded together on the walls of
the water-passages, or in the cellular tissue surrounding
the liver, kidneys, &c., and on this account it not unfre-
quently occurs that, even within the snail itself and before
the worms have been touched, such contracted misshaped
individuals are met with, recognizable only by the oblique
projections on the posterior half of the body.*

The “ zurses’’ usually present the appearance given in
fig. 4 a and. The body is cylindrical, and is furnished
in most instances with a spherical, contracted head, which
includes an oral cavity with very muscular walls, and a
small circular mouth. Below the head is a sort of collar
which abuts upon a depression, which according to the
greater or less state of contraction of the animal, is nearer
or further from the mouth. When the head is drawn
towards the depression, the collar projects straight out

* Baer has figured one in this condition. Nova Acta, Acad. Nat. Cur.
tom. xiii. tab. 31

64 DEVELOPMENT OF

like a broad fringe surrounding the body, and frequently
appears as if it were folded, and consisted of two lamine.
At some distance posterior to the middle of the body are
situated the two characteristic oblique processes, and
which, as well as the part of the trunk posterior to them,
which I designate a tail, are simply local dilatations of
the cavity of the body. Of mternal organs there is only
to be seen an undivided sacculated stomach, very small in
proportion to the size of the animal, and into which the
oesophagus opens, (see fig. 4 6.) The whole remainder of
the very large body is filled with the brood of Cercaria.
In the instance figured at 4 6, all the embryos have
simultaneously attained their full development, which is
but very seldom the case, since, in the same individual,
Cercarie are found in all stages of development.

The whole series of forms which the Cercarie pass
through within the body of their foster-parent, is repre-
sented in (fig. 5 a—5 m.) At first the germs from which
the Cercarie are developed are nearly spherical, and
appear to be formed of numerous vesicular globules or
cells, which are pretty clearly seen to be all surrounded
by a very delicate common membrane. ‘These spherical
germs afterwards increase in length as they are formed
into embryos, and during this growth one end becomes
much more dilated than the other. This unequal deve-
lopment continues in two opposite directions, so that the
more slender end gradually forms the tail of the embryo,
and the thicker its body. Thus the body and tail are at
first not merely united very closely, but form externally
one whole, and so long as this is the case, very weak mo-
tions are observed in the embryo, for mstance, when it is
irritated by any foreign matter, such as acids, &c., but it
is not entirely animate. As its growth continues, the
embryo begins to wriggle about with a worm-like motion,
and the more slender portion shows externally a dispo-
sition to separate itself from the thicker part ; but no very
lively motion is observable until the depression between
the tail and head is so marked, that the former can be

THE TREMATODA. 65

moved at all angles with the latter; on which account
the more the tail is developed, the more lively are the
motions of the embryo within its foster-parent; at the
same time the body has become more flexible, contrac-
tile, and extensible, and the abdominal acetabulum which
was indeed visible as a depression anterior to the root of
the tail, assumes now the distinct appearance of a sucto-
rial disc, but this organ like the tail does not attain its
full activity until the embryo has left the “ nurse,”
although it is frequently very prominent and expanded,
as shown in fig. 5 m, in which it is also seen how much
the abdomen is hollowed out, before the animal begins to
move about upon it. None of the internal organs are
evident before the embryos are fully grown; but at that
period, some organs are more distinct than in the free
swimming individuals which have escaped from the
“ nurses, viz., the organs filled with minute cells, which
in several instances of embryos taken from the “ nurses”
themselves, were clearly seen to be the two branches of a
canal which ran the whole length of the body between
the branches of the digestive organ, and appeared to open
into the cavity within the tail. The collar itself is formed
the last. Some doubt exists as to the mode in which the
Cercarie quit their “ nurses,” since it has been observed
under the microscope that there are two places at which
they come away, viz., from each side of the body in the
depression under the collar, and from the abdominal
surface between the two oblique processes, but they
escape from the latter situation only when the animal
has been slightly compressed between the glasses ; and
from the former on the contrary when no pressure at all
has been employed. It very often appeared to me that
there were two openings in the cervical depression, which
were surrounded as it were with elevated borders. That
the “ nurses” are able to discharge their brood of Cer-
carıe without external aid, is shown by the great number
of those creatures swimming about free in the internal
cavities of the snails; but that the contraction of the
5

66 DEVELOPMENT OF

snail itself, probably also exerts a considerable influence
in this respect is evident, from the swarms of Cercarie
which appear in the water when the snail is compelled to
contract itself forcibly within its shell. It would appear
that the Cercarie are expelled from the internal cavities
of the snail (the aqueous chambers, which extend be-
tween the viscera and are partly bounded by them, and to
the walls of which the “ nurses’”’ especially attach them-
selves) through the same minute canals, by which the
water enters those cavities, It is very rare, however,
that all the Cercarie come away ; some of them are re-
tained and swim about, as has been said, in the aqueous
chambers, and assume the pupa state on their walls when
they have found a fit spot, and there undergo the same
transformations as the individuals which have made their
escape into the water outside.

Siebold frequently found pup& in the snails, as I have
often done myself; Baer has also seen them, but not
understood what they really were, for he did not conceive
that the phenomena observed by Nitzsch in connexion
with the supposed death of the Cercarie was their en-
tering into the pupa state, but assumed that a single cer-
caria was placed ineach of the cases under the same
conditions as those to which a number of cercarie are
subjected, m the particular forms to which I have above
given the name of *‘ nurses.”

‘There is one organ especially in which above all others
the pupe of the Cercarie are met with, viz., the auricle,
in which if there are any pupze in the animal they are
sure to be found, and usually in considerable numbers.

In Planorbis corneus and Limneus stagnalis 1 found
pupee evenin the month of August, and afterwards
throughout the autumn.

In Paludina vivipara, in the auricle of which Baer so
constantly found the pupe, both of the Cercaria echinata
(Sieb.?) and of another species, the Cercaria ephemera
(Nitzsch,) especially the latter, that he states them to be
peculiar to that part, I have, in the winter and beginning

THE TREMATODA. 67

of the spring of this year, always met with the pupee of
the species here described, but also, only in the auricle,
although they occurred frequently in considerable num-
bers.

In some of the snails there were only from two to five
pupze ; in most of them from ten to twenty, and in several
even many more than thirty. Among the mdividuals ob-
served, the number of which far exceeded a hundred, only
about ten were met with, in the auricles of which, none of
these creatures were found ; but of Cercari@ themselves
or their “ zwrses,”’ I did not, during these months, meet
with the least trace. I have convinced myself by exami-
nations repeated almost weekly, that pupze all retaming
the same condition, occupy the auricle even after the
first ten days of June; if, however, the pupa cases are
opened during this period, the inclosed animalcules appear
to be on the point of leaving them, for they are unusually
brisk in their movements, (much more lively than those
which I observed m the sprmg months, after they have
newly escaped from the pup&,) have assumed the appear-
ance of flukes, and at least some of them, even before
leaving the pupa case, have lost their circlet of spies.

From this it is evident, that the Cercarie remain for a
long time in the pupa state, probably from two to nine
months, as might also have been conjectured from the
observations of Nitzsch upon Cercaria ephemera,” accord-
ing to which it is not improbable, that when left wholly
to themselves and to natural circumstances, they pass from
the pupa cases into a new form, which differs in some
respects from that which I have previously described and
figured from individuals which have been hatched as it
were by artificial warmth from the pup contained in

* Nitzsch (Beitr. z. Infusorienk., od. Naturbeschreibung. der Zerk. und
Bacill.,) says (s. 17) that his specimens of Cercaria ephemera lived three
mouths after the bodies had assumed the pearly aspect (that is, had become
pupe,) and regrets much that, as he expresses it, he was so foolish as to
throw them away, under the supposition that they would become nothing
more than they were, although their fresh condition would have induced the
suspicion that they retained the germ of a new life.

68 DEVELOPMENT OF

snails, which had been exposed for several months to a
degree of temperature unusual to them, and not been
furnished with their natural food. The individuals which
remain within the aqueous reservoirs, and undergo their
transformation in the interior of the snails, are specially
destined for the multiplication of the Distomata within
those animals; and on the contrary, those Cercarie
which are expelled through the water-passages, serve to
propagate the species on other snails, although some of
them may enter into the pupa state on the surface of the
same snail from which they had been expelled, and in
the interior of which their foster-parents had lived.

Let us now leave the consideration of the destiny of
the Cercarie which are not expelled from the animals
infested by them, and return to the “ zwrses,” in order
through them to come at the origin of the Distomata.
For this purpose, we must seek for the smallest indivi-
duals of that class, and endeavour to discover their primi-
tive form, so that we may be the better able to obtain a
glimpse at their origm. Here, however, we are met by
the difficulty, that although they may be found of a cer-
tam degree of smallness, yet that we can never get
beyond this, and find them still smaller. However, they
may always be met with of such small size and imperfect
form, that it is impossible to suppose they could have
originated in the transformation of Cercarie or full-grown
Distomata. Vig. 4 d, represents a very young individual,
about the youngest form I have been able to meet with
in the viscera of the snail, in the large masses of ‘‘ nurses’
which so often occur there, and which have received from
Siebold the name of “Cercaria nests.” These younger
individuals are distinguished from the older ones by the
proportionately larger size of the head and collar, and the
greater length of the ventricular cavity, which reaches
almost as far as the oblique processes. When visible
germs of embryos are present, they occupy only the pos-
terior portion of the cavity of the body, and do not
surround the stomach. It may also be remarked, that m

THE TREMATODA. 69

all these young individuals the skin was readily seen to
be composed of glandular, circular, nearly equal-sized
cells or vesicles.

I will now explain this origin of the very young
“ nurses.” Siebold expresses his surprise at seemg them,
(which he does not look upon as independent animals,
but only as living organs of generation, and with Bur-
dach designates as “living germ-sacs’) developed from
germs, which are always contained in other creatures
corresponding with them in outward appearance (germ-
sacs) ; but he seems to have seen this very seldom. I had
certainly had thousands of “nurses” under the micro-
scope before I saw this phenomenon, and I freely confess,
that for a long time I believed Siebold’s observation to
be founded on some illusion. In July, August, and Sep-
tember, I also saw no instance of it; but in the winter it
constantly occurred in some of the snails taken from the
same places as the others, that they harboured only ento-
zoa, which had the outward form of the “ nurses,” but
which contained a progeny consisting of actual “ nurses,”
in all stages of development. ‘This was the case only in
some, and those rather young snails, whilst all the others
were at the same time inhabited by “ »urses,”” whose
progeny was true Cercarie, and I, consequently, cannot
doubt but that it is normal for the “ nurses’ to originate
im creatures of similar appearance, and which are thus
the “ nurses” of “ nurses.” These “ parent nurses”
(abaltrices) notwithstanding their great external resem-
blance, were not difficult to be distinguished from the
common ones; the stomach, for mstance, in the full-
grown “ parent nurses’ filled with their progeny of em-
bryo “‘ zurses” was longer and wider than in any even of
the youngest “ nurses,” (compare fig. 2 a and 2 4 with
4 cand 4 d.)

In figs. 2 ¢ and 2 d are seen the “ parent nurses’ in
their younger form. The embryo “ nurses”’ are contained
only in the posterior part of the bedy, between the two
lateral processes, which is the same situation as that

70 DEVELOPMENT OF

occupied by the germs of the Cercarze in the “ nurses”
themselves, and it cannot be doubted that the germs are
always collected in that situation as in a distinct organ
(uterus ?), and that by the development of these germs
into embryos and the growth of the embryos, this organ
is enlarged, and consequently the whole cavity of the
body of the “‘ nurse’”” distended and filled. In the same
way that the Cercarig within the “ nurses’ attain their
full development only by degrees, the “ nurses’ also
within Zheir parents do not reach their full growth simul-
taneously, whence it must be assumed, that they, like the
Cercarie, are not all born at once. The series in the de-
velopment of the “ murses’’ from perfectly spherical germ
granules is represented in figs. 3 a —— 3 p, and will
afford when compared with the development of the Cer-
carie given above, and notwithstanding their great re-
semblance, evident signs by which it may readily be
determined from the appearance of the embryo itself,
whether a Cercaria or a “ nurse’ (altria) is about to be
formed from it. |
That the oral orifice and the head of the “ muses” and
“ parent nurses’ are identical with the parts of the same
name in the (ercarie ; that the constitution of the collar
is the same in all three forms or generations; that the
lateral processes of the “ nurses” and “ parent nurses’ are
the projecting borders of the posterior part of the body,
on each side of the root of the tail in the Cercarie ; and
finally, that the tail, although the Cercarie lose it, is also
‘the same organ in all three generations, are points to
which I surely need scarcely direct attention ; and all con-
jectures,* as to whether or no either the whole of the
“ nurse’ or “ parent nurse,’ or some of their organs,
may have a different object, must in my opinion cease of
themselves.
We have thus followed the Distoma to its third stage

* As, for instance, the common opinion among the Germans that the
“nurses” axe only vitalized generative organs; Siebold’s supposition that the
lateral processes may possibly perform the function of organs of nutrition, &e.

THE TREMATODA. vB

in ascent, and I have not been able to detect any more
generations ; and am, consequently, not in a condition
at present to trace the origin of the Distoma further
back. I entertam, however, the not unfounded supposi-
tion, that the “ parent nurses” do not arise from other
similar creatures, but that ¢hey proceed originally from
ova; for, as is stated above, (p. 61,) it must be assumed
that the full-grown fluke, like all other species of this
genus or family, is oviparous. I will afterwards exhibit
the reasons which induce me to believe that it is the third
generation, or the “ parent nurses’ which are produced
from the ova; whilst I will also prove, that animals such
as those which I have named “nurses” and “ parent
nurses, belong to the series of development of the .Disto-
mata, and derive their origin from ova, which have been
produced by the Distomata themselves.

With regard to the link which is deficient in the de-
velopment of the “ parent nurses,” and for want of which
we are unable to deduce their immediate origin from the
full-crown Distoma, so that all the generations here
referred to would constitute a complete cycle (cyclus), we
may forma tolerably correct notion of what it is like b
help of the observations which were published by Siebold
some years since, in the first number of ‘ Wiegmann’s
Arch. fiir Naturg.’

Monostomum mutabile is an entozoon of the trematode
family, which inhabits several of the cranial cavities lined
with mucous membrane in certain water birds, and is one
of the small ¢rematoda, the embryos of which are fully
developed in the ova, while still a utero. The young
embryo is frequently hatched before or just as the ovum
is expelled, and in this case, the Monostomum mutabile 1s
ovo-viviparous. The newly-hatched young (fig. 1 4) are
elongated, oval, furnished at the anterior extremity with
some short lobes, which the animal is able to protrude
and retract, and its whole surface is covered with vibratile

12 DEVELOPMENT OF

cilia, by aid of which it moves readily in the water. In
the anterior portion of the body are two quadrangular
spots which are inclined obliquely towards each other,
and can scarcely be regarded as anything but eyes. The
posterior two thirds of the trunk are occupied by a slightly
transparent, whitish body (g), which it might be supposed
was an organ as Siebold thought it to be, if it were not
that after a time, and some rather vigorous motions, it
becomes detached, ruptures the body of its parent, and
presents itself as an independent animal of entirely
different appearance to that m which it lay concealed, and
was already developed (fig. 1 a g,) whilst the latter was
still within the ovum.

Now, since this inclosed animalcule is constantly
present in the ciliated young Monostomum, and as there
is always but one animalcule in each individual, and
always in the same situation, there must necessarily be
some organic connexion between the two, and one
entirely different from that which it has been supposed
could be explained by styling the one a necessary parasite
of the other. If one animal is, organically speaking,
necessarily connected with another, so that each can be
developed only zm or around the other, they must belong
to one and the same unity, or constitute such a unity,
and this is doubtless the case with the animals we are
now considering.

Fig. 1 4, represents the embryo Monostomum recently
born, and possessed of sufficient locomotive powers to
enable it to seek out a fit habitation; when it has met
with this, the ciliated integument, and the eyes now use-
less, are thrown off by the animal stripping itself of the
whole of its skin, together with which it loses also its
external form, and becomes the sluggish creature (fig. 1 ¢
and 1 d,) whose motions are confined to a vermicular
wriggling. The first form of this embryo is not unlike
that of the common ciliated progeny of the Trematoda, as
they have been known to us in many species for a long
time, from the observations of Mehlis, Nordmann, and

THE TREMATODA. 73

Siebold, and it might at first sight be taken for one of
the polygastric mfusoria of Ehrenberg, which also move
by means of ci/ia ;* whilst in the next form which it
assumes, the young Monostomum bears an undeniable
resemblance to those animals which I have termed
“nurses” and “ parent nurses,” in that species of the Zre-
matoda which is developed from the Cercaria echinata. In
this second or altered form (the necessary parasite) the
anımal, according to Siebold’s figure, appears to have a
mouth at the anterior extremity, within which there seems
to be a muscular oral cavity. At a short distance below
the mouth there is an evident depression, indicating as it
were a short neck (fig. 1 d,) resembling that in the
“ nurses’ and “ parent nurses ;’ at the posterior part of
the body there are two lateral processes, and behind these
a shorter, moderately thick tail or prolongation of the
body, which in like manner correspond to the same parts
in those creatures.

If objection be made to the view which does not regard
the change from the active state represented in fig. 1 4,
into the sluggish animalcule fig. 1 c, as a metamorphosis,
I will with respect to this point further remark, that the
mode in which these two apparently different animals lie
one within the other, recalls completely the conditions
under which the sluggish short-tailed Brachyurus lies
within the active long-tailed Macrourus, and the form
which it has on escaping from the ovum, but which it
afterwards loses.

Now, since the progeny of the Monostomata—a family

* I believe also that it may be regarded like the other Polygastrica, as
possessing many stomachs; and it appears to me, that the dispute about the
many stomachs of the Polygastrica may carry us further than to assertions
which are merely opposed to each other, if the analogy or want of analogy
of these infusoria, with the earliest foetal conditions of several forms of
animals, is followed out.

7 An abridgment of my observations on the metamorphosis of the Orzs-
tacea (sand-crab, Hyas araneus ; and the hermit-crab, Pagurus Bernhardus ;)
and on the various regions in the water inhabited by the young ones in the
various stages of their development, is given in Oversigt overdet kongl-
danske Videnskabsselskabs; Forhandlinger for Aaret, 1840; and in Valentin’s
Repert. 1840.

74 DEVELOPMENT OF

closely allied to Distoma, changes its form in this way,
and by deing so acquires a remarkable similarity to the
“ nurses’ and “ parent nurses’ of the genus Distoma, the
course of whose development I have endeavoured to
exhibit, and since this progeny in consequence of its
metamorphosis rather becomes more unlike the form of
the parent animal than approaches it, it will surely not be
considered too bold to assume, that the animals which are
the immediate result of the metamorphosis, do not by
another transformation become actual Monostomata, but
that they develop the germs which do eventually become
perfect Monostomata, or in other words, that these meta-
morphosed young ones are to be considered as “ nurses.”

If we now introduce a link such as we have presented
to us by the Monostomata, into the series of develop-
ment of the Distomata given above, the whole cycle will
be completed, and as I should hope organically completed
or nearly so. Several examples of the same kind will be
presented in what follows.

(6) CRRCARIA ARMATA, Siebold.
(Tab. ii. fig. 1—6.)

As I am obliged by want of space to be as brief as
possible, I shall refer as much as I can to the figures
and to the communications of Siebold respecting this
species,* as I have no doubt but that the one I have
before me is the same with that described by him—
although in this case, Wagner's figure referred to in
Oken’s ‘ Isis,’ (1834, 1, tab. 2,) is not quite correct,—and
because I think that figures will give a much more correct
idea of the animal than a lengthened description.

This Cercaria is scarcely half the size of the former
one, but is equally lively and active in all its parts;
though it has not the power of rolling itself into a ball
when swimming in the water, and the tail does not on

* In Burdach’s Physiologie. 2d edit. tom. ii, p. 187, seq.

THE TREMATODA. 75

each stroke form the same 88 or SS figures ; but the body
and neck undulate alternately while the animal is swim-
ming. On fixed objects in the water the creature’s
motions are more leech-like, in which case it makes use
of the abdominal acetabulum ; I have seen hundreds of
the Cercarie creeping in this way on the slimy cuticle of
Limneus stagnalis and Planorbis corneus, whilst thou-
sands were swarming about every snail in the glasses.

Their incredible numbers frequently made the water
turbid, and I have not unfrequently observed the same
thing to occur naturally in stagnant pools in the neigh-
bourhood of Copenhagen and Sörö (in the marsh Flom-
men,) in which these animalcules were swarming. This
observation, in conjunction with another, that they
always keep as it were in whole swarms around the
snails, appears to me to be not unimportant with regard
to the mode in which they are conveyed from one animal
to another.

Of the internal organs, which are visible through the
more than half-transparent integument, the most striking
is the minute, linear-pointed, hard spiculum, placed
above the oral cavity, immediately under the skin, and
which projects so much with its pointed extremity from
the skin, that the species has been rightly named armata;
besides this, there is an elongated organ which com-
mences at the anterior extremity of the animal on each
side of the spiculum, and passes down along the sides of
the body; but to the middle of which I have been only
occasionally able to trace it, and at that point a clear spot,
surrounded with one or two darker rings, indicates the
situation of the abdominal acetabulum and its borders.
Before the root of the tail, as in the former species, is
situated a clear spot, capable of being expanded and con-
tracted, which from long examination of several species of
Cercarie, 1 believe to be nothing but the transverse
section of the tail where it is attached to the trunk, seen
through the skin. The body is slightly excavated poste-
riorly, to receive the tail, and the lateral portions which

76 DEVELOPMENT OF

embrace its root are of somewhat firmer consistence than
the rest of the trunk, and appear during the continual
motion of the animal to be used by it as a pair of stumps
or feet to push itself forwards with. The tail cannot ever
be extended so far as to cause the disappearance of the
depression in which it is inserted, or of the lateral folds ;
its internal cavity reaches as far as the body, but I ham
not been able to trace it further. 'The whole animal is
covered with an extremely delicate transparent cuticle, be-
neath which the skin, which is highly glandular, secretes a
viscid, yellowish-white slime, which hardens under the
water, and is of considerable importance during the fur-
ther development of the Cercarie.

The fact that this Cercaria, like the former, assumes a
pupa state, has been already observed by Siebold, who
has described the phenomena attending that change, in
Burdach’s ‘ Physiologie,’ t. uu. I will now only add, that
it crowds about the water snails in much larger swarms
than the preceding species, and attaches itself to their
uncovered portions in such numbers as to give the sur-
face a flocculent appearance, and that after crawling
about for some time, it assumes the pupa state. It is
during this creepmg about on the cuticle of the snail that
the Cercaria exhibits the thrusting or piercing action
which is seen to attend its motions on the object-stage of
the microscope. Attaching itself by means of the abdo-
minal sucker, and pushing itself as it were by the pro-
jections on each side of the root of the tail, it thus thrusts
the fore part of the body and the spiculum placed on its
anterior extremity, with considerable force against the
skin of the snail, which is in this way apparently per-
forated, for immediately afterwards the Cercaria is seen
to be sunk or buried in it, and covered with its shme. If
the tail has not previously been detached by the vigorous
movements during the alternate attachments and creeping
about of the Cercarie, it now becomes so; and since by
this separation of the tail its internal cavity is divided, a
new opening is produced at the posterior end of the

THE TREMATODA. ag

body, through which a fluid containing numerous glo-
bules is expressed. I must suppose with Siebold, that
this is the proper excretory organ of the Distoma, which
thus obtains an exit. For it cannot be doubted that
the fluid secreted and contained in this organ is of an
entirely different nature in the Distoma to that in the
Cercaria or its “ nurses” and “ parent-nurses,’ since m
the former it is rejected, and in the latter retamed in the
body.

When the Cercaria is buried in the skin of the snail,
it apparently secretes from its whole surface a very large
quantity of slime, in which the animal, which we recog-
nize as a distoma-larva, is m continual motion around the
same point; and as the mucus gradually hardens, a case
is as it were formed around it (fig. 44). The walls of
this pupa case appear to be thickened by a delicate
membrane, which is shed doubtlessly from the body of
the animal itself, smce the spiculum mentioned above is
always found to be cast off, and to be stationary at some
part or other of the walls of the cyst, although during the
circular movements of the larva within the case it had
been carried round from side to side together with it.
The detached spiculum is afterwards covered over, and
walled off by a distinct layer of mucus. (Compare 6 in
figs. 4d, 4 e, and 4 f.)

In a few hours after the Jarve or Cercarie have af-
fixed themselves to the skin of the snail, nearly all of
them have assumed the pupa state; and the oval pupze
may be placed so close to each other on (the back |nacken]
and edge of the mantle of the snail) that a portion of the
skin viewed under the microscope resembles, in miniature,
a pavement composed of oval pebbles; and this is the
case not only in snails which have been kept in glasses
and in a small quantity of water, and consequently ex-
posed to great numbers of their enemies, but also in
those taken from pools of water in the natural state.
After entermg the pupa state, the animal appears to
shrmk away from the sides of the case, so as to leave a

78 DEVELOPMENT OF

small interval between it and the cyst, but it contmues
its movement not the less for many weeks, though
perhaps with diminished activity.

I conclude that a long time elapses between their be-
coming pupz and their quitting that condition, partly
because I have had pupze under observation for several
weeks, and partly because I have examined in a state of
nature, hundreds of pupze which clearly showed that the
animals had lain for a long time in that condition. 1
have several times endeavoured to preserve a considerable
number of pupze in the living state between slips of glass,
but have only once succeeded in keeping them alive until
some of the animals crept out, which occurred m about
ten days from the commencement of the experiment. All
the rest remained in their previous condition, until at
last, by imprudently wetting them with cold water, I
killed them outright.

Several of the external and internal organs are visible
through the transparent pupa case, which without great
difficulty may be referred to those of the Cercarie, since
during the act of the creatures assuming the pupa state,
we have the opportunity of tracing the metamorphosis of
at least some organs, and the position of these may then
throw some light upon the others. The most prominent
of these is of a horse-shoe shaped figure in the hinder part
of the pupa; this marks the position of the semicircular
lateral projections which surround the root of the tail,
and which have apparently become thicker and larger in
consequence of the contraction of the body. Between the
two arms of the horse-shoe (£) is situated the opening of
the proper excretory organ (vide Ad, 4e,4f,49). A
more or less circular spot or rmg im the centre of the
animal is the acetabulum (x) ; a three-lobed organ, which
when regularly contracted is shaped like a trefoil leaf, is
without doubt a digestive organ or stomach, with its
club-shaped lateral prolongations, for immediately ante-
rior to the central lobe of this organ, under favorable
circumstances, an opening or mouth may be perceived on

THE TREMATODA. 79

the anterior edge of the animal, and a delicate canal
passing down from it to the central lobe.

Besides these, I clearly distinguished a tolerably large
double organ (2, fig. 4 /, and 4 ,) the two branches of
which, proceeding from the anterior extremity of the
animal, and passing in a curved direction around the
stomach, unite in the mesial line behind the acetabulum,
and appear to be connected with a rounded swelling,
which is seen like a circular clear spot m front of the
horseshoe-like outlines of the posterior borders of the
animal. ‘The situation would render it not improbable
that this double organ is connected with the function of
reproduction.

The animal does not appear to creep out of the pupa
case through any regular opening, for close to the indi-
viduals above referred to as having just left the pupa
cases, I observed the latter irregularly crumpled up, and
scarcely recognizable. Fig. 5 @ represents an animal
newly escaped from the pupa case; several of its internal
organs were still apparent for the first hour or two
through the tegument ; its changed condition, however,
afterwards prevented their being distinguished. The
organs marked s, f, w, v, are the same with those simi-
larly lettered in fig. 4, and I suppose it is the same with
that marked 2, though I am unable, in the pupa, to dis-
cover a connexion with the organ marked v, as in the
animal. The figures 5 4 ¢ d, represent, for the purpose
of comparison, individuals which I obtamed at the same
time from pupa cases, either by opening them or bursting
them by compression between slips of glass. They are
evidently true Distomata. 'The most important changes
which are observed durmg the growth of these animals
consist in the very powerful contraction of the body, the
shape of which changes from the broadly lanceolate which
it is normally, to an obovate or pyriform, in consequence
of the anterior extremity constantly increasing im breadth
(fig. 5e f g). Simultaneously with this change of form,
the activity of the animal dimmishes, and becomes at last

80 DEVELOPMENT OF

so much impaired, that it may be looked at for a long
time, without giving certain signs of being a living
creature. In this full-grown state they are covered by
a very thick cuticle, appearing as if they were enveloped
in a thick layer of inspissated albumen; and this albu-
minous cuticle is a great obstacle to observations, in con-
sequence of its elevated spherical surface refracting the
rays of light.

This Distoma, as it is represented in figs. 5 e-A, occurs
frequently in the liver and generative organs of two of our
larger fresh-water snails, Zimneus stagnalis and Planorbis
corneus, and in some snails, in assemblages of 10-50. In
this condition it would scarcely be taken for the same
animal with that which we have previously been consider-
ing as Cercaria armata. At first sight there is visible
beneath the thick cuticle only an irregular network of
canals, filled with a fluid contaming minute globules; a
closer examination shows us, in a sharply defined circle
in the centre of the animal, the acetabulum or sucker ;
in two semicircles turned towards each other, we perceive
the wider ends of the digestive cavity ; and in depressions
and tubes which pass through the thick mtegument,
we see both the mouth and the anus, the latter being
recognizable by the fluid loaded with cells which it emits,
and by its situation between the posterior horseshoe-
shaped borders, which serve as a sucker.

It is not difficult to comprehend in what way the Dis-
tomata, after leaving the pupa case, enter the nobler organs
of the snail, since we saw them buried in its skin whilst
assuming the pupa state. I have very seldom been for-
tunate enough to meet with them m the skin soon after
their quitting the pupa state; they were at that time
very active in their motions. I have also found them
3 and 1” under the skin, on their passage inwards,
and have no doubt at all that they afterwards chiefly
follow the course of the aqueous canals, and thus enter
the animal much in the same way as when, in the form ,
of Cercarie, they came out of it.

THE TREMATODA. 8]

I have, however, satisfied myself that very far from all
the individuals reach the organs mentioned above, viz.,
the liver and generative organs; for I have observed
great numbers of them full-grown which could not be
distinguished from those in the liver, occupying the ca-
vity m the head and anterior part of the body which is
filled with a slimy fluid, and in which the nervous ring
of the pharynx is situated, in the cavity around the heart,
and in several other situations, so that this Distoma is
not one of those species whose full development is re-
stricted to one organ of the animal infested by them.

We have thus again traced a free swimming Cercaria
or Distoma-larva, until it is deposited as a true entozoon
Distoma or fluke, deep in the organs of the snail; we
shall now see that it has previously inhabited, also, the
interior of a snail, although not of the same one. The
observations already referred to of Bojanus, Baer, and
Siebold, have proved that all Cercarie occur in sacciform
bodies in the interior of snails, and the sacs in which
these animals are situate have been described by Siebold,
in Burdach’s ‘ Physiologie,’ 1.c. The figures 1 f and
lg represent sacs of this kind, containing numbers of
developed and undeveloped Cercarie ; and if one of these
sacs is opened, the whole series of forms through which
the Cercarie pass can be readily followed (figs. 2 a—g,)
from the globular gemmules to the perfect forms, which
as soon as they have quitted the sac, can no longer be
distinguished from those swimming free in the water.
It may be soon ascertained that the whole course of de-
velopment entirely corresponds with that of the former
species. The parts which are completed last are the
frontal spiculum and the double tortuous organ, which
passes down on each side of the body.

By the first inquiries it was soon determined that a//
Cercari@ origimate in the sacciform bodies, and that
these always contain Cercari@, and grow and are de-

6

82 DEVELOPMENT OF

veloped along with them ; but the earlier observers con-
ceived an erroneous notion of the true nature of these
sacs, since they even denied that the present kind enjoy
independent existence and vitality. Siebold for mstance
says, that the sac is “ a pouch closed on all sides, and
possessing neither intestine nor mouth, colourless, and
exhibiting no sign of life.” This is not altogether un-
true with respect to the sacs when they occur in large
clumps and masses in the liver, kidneys, or other in-
ternal organs, under circumstances when their great
numbers have prevented their free development; for
then, certainly, no sign of motion is perceptible in
them, and should any be perceived, it is impossible to
distinguish whether it be referrible to the sacs them-
selves, or to the Cercarıe swarming within them. But,
if smaller, that is, younger sacs, or above all, sacs con-
taining only a half-developed progeny of Cercarie, and
which lie free, or scattered on the surface of the organs,
or what is still better, attached to them by one end only,
and with the whole body hanging out in the surrounding ©
water passage be observed, an evident twisting and
winding, vermicular motion will be perceptible in them.
I have even met with solitary sacs on the walls of the
water passages, in which a few slow movements were
perceptible, which besides the usual rolling or turning
on the axis, consisted in a contraction and extension,
which at other times has been very seldom observed. In
these solitary sacs it was also manifest, that the surface
by which they adhered to the organs of the snail, formed
a sort of acetabulum, which however had already lost
all power of motion, and was scarcely capable of again
affixing itself by suction when once detached.

I have also witnessed something like this in sacculi
which had been immersed in luke-warm water, and very
carefully separated from the heap or mass which was often
deposited as thick as a swarm of bees upon the branch of
a tree, around and in the organs of the snail.

In the smallest sacculi which I could find (fig. la, b )

THE TREMATODA. 83

and which, as it were, filled every snail with their thou-
sands, such a depression was zever wanting at one end,
and at the opposite extremity I could always distinguish
another smaller depression or opening, the skin over which
was sometimes elevated in a vesicular form ; in these I
was certainly unable to detect the germs of the future
progeny ; but before they had doubled their size, and
while still not so large as the bodies of the Cercarie
afterwards to be developed in them, I could very plainly
distinguish the germs in the form of rounded granules.
The whole alteration undergone by these sacculi during
their growth (figs. | a—f) may perhaps be conceived in
this way; that the supposed sacculi are not hollow in their
earliest state, but consist throughout of a mass of glo-
bules and vesicles; that while they are still extremely
small, a minute cavity is formed within them, in which
the germs of the future Cercarie are situated ; that, nor-
mally a simultaneous increase goes on of the germinal
cavity, and of the supposed sacculus itself, the walls of
which evidently consist of numerous round glandular ve-
sicles. The independent motions which are observable in
them in this condition cease altogether when the embryos
approach the cercaria form, and the whole integument is
then distended into a thin membrane in which any or-
ganized structure can with difficulty be distinguished.
Now, as these presumed sacculi, at least at one period
of their existence, are capable of spontaneous motion, and
are only in appearance destitute of organization, since they
are seen to grow or increase in bulk by organic means,
we must certainly consider them as animated beings, and
according to the observations adduced in the preceding
pages, even as animals which stand in such intimate
relation with the Cercari@, that these latter occur only
in the sacciform animals, and on the other hand the
sacciform animals always contain Cercarıe more or less
developed. They must consequently both be necessary
parts or lmks of one and the same unity, and I have no
hesitation in placing the sacciform individuals in the same

84 DEVELOPMENT OF

species with the Cercarie inclosed within them, or with
the Distoma into which the Cercari@ are transformed after
passing through the pupa state. They are thus indivi-
duals which remain stationary at a particular stage of
development, not much higher than that at which the
Cercarig commence, and which have undergone as it were
a retrograde metamorphosis, m order to promote the
perfect development of the brood of Cercarie committed
to them ; in other words, they are individuals of the kind
which I have in the foregomg pages denominated “ nurses.”
The existence of such “ »ursing” animals within a species
can no longer be considered singular, when the facts ad-
duced in the preceding sections are brought into compari-
son ; and their origin can also no longer appear mysterious
when it is remembered, that sluggish creatures resembling
the “ nurses’ or “ parent nurses” of the Cercaria echinata
arise from the metamorphosis of the active young of Mo-
nostoma mutabile. In the following pages I will relate
precise observations, to show that these saccular and ap-
parently altogether lifeless “ zurses’”’ originate directly —
from very lively animalcules; but before proceeding to
these observations, I will offer some considerations on the
subject of the “ zursing” animals now before us.

In the earlier researches upon the Cercarie, the sup-
position is sometimes directly broached and sometimes
understood, that the “ aursing” animals, the supposed
sacculi, were probably only the smaller and distended
bodies of the Cercari@, from which, consequently, they
must have originated through a kind of metamorphosis ;
but I believe that this opmion is confuted by what has
been stated in the preceding observations, and that there
is no doubt but that the “ »urses’” are developed from
very minute oval corpuscles or germs, and that thus they
and the Cercarie contained within them, pass through a
parallel series of developments, and that there is no room
for supposing that any metamorphosis or transformation
occurs from one series to the other.

It seems as if the earlier observers could not under-

THE TREMATODA. 85

stand how the Cercarie which had attained their full
growth, escaped from the close-shut sacculi which the
“ nurses” appeared to them to be; and when the whole
swarm of Cercarie is seen moving about within the contain-
ing cyst, it certainly seems as if they were endeavouring to
find an outlet. I have no doubt but that the animal is
provided with such an outlet, since I have been able to
demonstrate in the younger “ nurses” at least two open-
ings, without however being able to determine the precise
function of each ; and I have besides so often seen a series
of Cercari@ one after another escaping from the orifice at
the free extremity of the “»xrse,” that I have been in-
duced to consider that opening as their natural exit. The
correctness of this opinion would further appear from the
fact, that the above phenomenon is always observed to
occur in the same spot, even when the animal has not
been subjected to the slightest pressure. That this birth,
if such an expression may be used, most frequently occurs
when any circumstance promotes the expulsion of the
brood from the “ zwrse” is natural, and its occurrence is
readily explained by a phenomenon which is at first sight
surprising, that thousands of Cercarie will suddenly be
seen swarming in a glass of water, when a snail placed in
it is compelled in some way or another to withdraw itself
quickly into its shell. As has been previously remarked,
when the “urses’’ are compressed in this way by the
surrounding organs, the progeny is expelled and carried
together with the water forced out by the contraction of
the snail, through the canals, into the surrounding water,
im which we found them when we began to trace the his-
tory of their development.

That such a half natural, half artificial birth is not the
lot of all Cercarie is evident, even from the observations of
Siebold, who has sometimes noticed within the “nurses,”
and among half developed Cercarie, some individuals
which having already cast off the tail, were in a con-
dition to assume the pupa state. I have had numerous
opportunities of confirming this observation and even of

86 DEVELOPMENT OF

extending it, having seen them sometimes as perfect
pupe in that situation. Hence it necessarily follows, that
the Distoma proceeding from one of these pupe will be
found within the “ »urse,’’ and would be as it were an en-
tozoon to it rather than to the snail. Such an occurrence
as this is represented in fig. 6 a, where a Distoma-like
individual lies under the creeping multitude of Cercarie,
and has already attained such a size as certainly to prevent
its exit, except by rupture of the “ nurse.” I have wit-
nessed this interesting sight in only about twenty or thirty
individuals, amongst thousands of “ zurses’” which I have
had under the microscope ; an entirely different circum-
stance, however, which occurred in some snails is not to
be comprehended in this account. These had all their
internal organs nearly full of large “ nurses,” of which
every fifteenth or twentieth individual had one, two, or
three full-grown Distomata lymg under the remaining half
or fully developed brood; two even had more, the one
four and the other five flukes or Distomata (fig. 6 6.) In
these the mode of arrangement by which they occupied
the smallest possible space was very evident; this was
effected by their being placed alternately with the broader
and narrower end towards the same side, and this regu-
larity of position occurred even when there were only two
or three within the “ zurse.” It would not therefore be
extraordinary, if we should here and there meet with
“nursing organisms, containing only full-grown Distomata
and no Cercari@ at all; since it is evident from what is
stated above, that even the whole progeny may possibly
attain their full development within the “ »xrses.” Thus
we are furnished in this case with an instance of the Cer-
carıe becoming pupe, and of their emerging from that
state within the bodies of the “ zurses ;” the Cercari@ also
frequently enter into the pupa state within the cavities of
the snail, especially in the aqueducts, the walls of which
are occasionally seen covered with pupe, and by this
means the number of the entozoa infesting one and the
same snail is of course very remarkably increased.

THE TREMATODA. 87

(ec) CERCARIA EPHEMERA, Nitzsch, and Distoma
DUPLICATUM, Baer.

It has been shown by the development of Cercaria
echinata and C. armata, that both these species enter the
snail from without, become pupe upon and within them,
and after quitting the pupa cases, penetrate, as forms of
the genus Distoma, into the internal organs, which they
inhabit as true entozoa, so that it is no longer a mere hy-
pothesis, but an ascertained fact, that at least some entozoa
enter the animals infested by them from without ; we have
further seen, that both these species of Cercaria are
developed only within special organisms, which must be
considered as independent creatures, and as individuals of
the same species as the Cercarie themselves, but which
as regards their form differ very widely from the latter,
in consequence of some of their organs having been deve-
loped at the cost of others, in order to contribute in the
greatest degree possible to the development of the germs
of the Cercarie.

These animalcules, which, on account of the office they
fulfil have been termed “ zwrses,”’ derive their origin, as
regards the one species from nearly similar animals, in
the bodies of which they were developed from gemme,
and which in all probability, and according to all analogy
had originally proceeded from the ova of a distoma in the
form of ciliated embryos, and had afterwards undergone
metamorphosis.

With respect to the second species C. armata, my ob-
servations have not yet shown a similar development
with “ nurses” of a second generation, or ‘ parent
nurses as \ have called them, although I have occasionally
seen several “ zwrses’”’ of this species which were inclosed
as it were in a common membrane, which might be
supposed to be perhaps the delicate integument of the
“parent nurse.”

88 DEVELOPMENT OF

However, in order that the observation that the species
of Distoma which is developed from the larva of Cercaria
echinata does not attam its complete form till the third
generation, should not stand alone and unsupported by
analogy, I will state some observations on another species
of Cercaria, although it must be done with great brevity,
and I am not able to give any figures illustrating their
development.

Cercaria ephemera (Nitzsch) was the first species of
Cercaria intimately known to naturalists, and indeed only
through Nitzsch’s curious observations of the phenomena
attending their becoming pupe. More lately, Baer so
commonly noticed their pwpe in the auricle of Paludina
vivipara (without, however, knowing any more than
Nitzsch, that they were really pupe,) that he termed them
a species of Cercaria peculiar to the auricle ; and Siebold,
(l. c.) has again observed and described them in the pupa
state. I also have had several opportunities of becoming
acquainted with them, and will only add as regards these
animals themselves, that I have obtained several Distomata -
from the liver of Paludina vivipara, which from their
external form I am compelled to regard as the species
into which the Cercaria ephemera is metamorphosed from
the pupa; however, the want of individuals newly come
out of this state, prevents proof of this assertion being
given. ‘The “ xwrses’ of this species have, on the con-
trary, as far as I know, been described only by Siebold,
and as far as my observations themselves extend, they
correspond with those of that helminthologist ; they may
for instance be compared with the “ nurses” of Cercaria
echinata ; like them they are elongated, cylindrical ani-
malcules, having vermicular motion; they have a well-
marked muscular mouth; and a very long and wide
digestive cavity, which causes a protuberance in the middle
of the animal, and reaches even to its posterior extremity;
it has no lateral processes. The Cercaria ephemera lies,
in all stages of development, between the digestive cavity
and the skin, but never in great numbers; as soon as it

THE TREMATODA. 89

is little more than half developed, the two opaque ocel/z,
characteristic of this species, appear through the skin.
Siebold remarks, that he has found these “ nursing ani-
mals,’ or germ-sacs, within other similar “ nursing ani-
mals, or other germ-sacs, and thus it appears evident
to me, that the Dzstoma into which the C. ephemera is
metamorphosed, must be removed at least three genera-
tions from a Distoma like itself, or im other words, that
from its ova complete distoma-forms do not proceed till
the third generation.*

* Since I have ventured to explain Siebold’s expressions a little in ac-
cordance with my observations, it will be proper to give my reasons for
doing so; what he says with respect to the development of the “wrses”
is thus expressed :—“ I have here and there met with a ‘germ-sac’ (keim-
schlauch), m which I have observed among the Cercaria germs one, and some-
times two, or more oval, colourless bodies, furnished with a distinct pharynx
and a simple cecal mtestine. These bodies were of nearly the same size as
the bodies of the Cercarie. The intestine was much convoluted, and occupied
nearly the whole cavity of the body. Similar oval bodies, which were evi-
dently to be regarded as young ‘ germ-sacs’ (since in those which I disco-
vered in the ‘ germ-sacs’ of Cercaria echinata IL could clearly distinguish the
two posterior processes as small tubercles) presented themselves, on some
occasions, also in the same situation in a young Cercaria (cercarien geniste) ;
there might likewise be observed, by aid of the microscope, between these
smallest germ-sacs and the full-grown sacs filled with embryos, some of
every size, so that their growth could be accurately traced, and the gradual
completion of the yellow, granular vesicular bodies, and of the germ-
granules clearly observed.” (l.c. p. 190.) It is clear that Siebold met with
“ germ-sacs, as 1 had with ““zurses,” in all stages of development, and even
within other “ germ-sacs,’ which, moreover, he could not distinguish from
them; but in these they are placed among the Cercaria germs, one, two, or
more together, in the form of oval, motionless bodies, of about the same
size as the bodies of the Cercarie. It must consequently be believed either
that nurses and cercarie are developed together in one body, or that one and
the same creature (“germ-sac”) develops both zurses and Cercarie, and even
simultaneously, which in my opinion would be erroneous. For it is seen
that the “zurses” of both species, C. ephemera and C. echinata (Sieb,) present
the same phenomena ; now since I have observed in hundreds of the “‘ zurses”
belonging to the latter species, that they are developed from germ-granules in
other “zurse”-Lke animals, (“ parent-nurses”) in the same way as the cercarie,
but that these latter never contain anything but germs of “nurses,” I must
suppose that it is the same with the former, and am encouraged in this
supposition by Siebold’s having met with extremely minute embryo “nxrses”
in them; and he expressly says that they lie not among Cercarie, but among
their germs, and a confounding of “ nurse”-germs and Cercaria-germs may
occur very readily, especially when it has not been remarked that the
“nurses” axe developed from germ-granules, as probably Siebold had not
happened to do.

90 DEVELOPMENT OF

In order to place in the clearest possible light that
which, in the development of the Distoma, is effected
through several alternating generations, I will adduce as
an observation precisely to the same point, that a minute
oval animalcule which moves by means of cilia, and in
that respect resembles the offsprmg of the ova of the
Distomata, becomes in the third generation a Distoma-
like animal. There is found for instance both in the in-
ternal organs, and in the external mucus of our common
fresh-water muscles (Anadonta) an extraordinary quan-
tity of animalculze, appearing to the naked eye like minute
oval points, transparent, with milk-white extremities and
having a peculiar rotatory motion. Under the micro-
scope they appear reniform, very flat, with opaque extre-
mities, and as it seems are covered with vibratile cilia, so
that they call to mind a Paramecium or Colpodium, to
one of which genera they might not improbably be re-
ferred, had we sufficient means of determining the point.
I cannot avoid supposing, that the figs. 7, 8, 9, tab. 73,
(Zool. Dan.,) refer to this animalcule ; and it is certain,
that it is these animals which Baer, in his memoir on
Distoma duplicatum mentions, under the name of Para-
mecium, and describes as a “‘ chaotic swarm’’ in the inte-
rior of the Anadonta.

These paramecium-like animalcule, crowd about in the
aqueducts, both m the mantle and in the foot and in-
ternal parts of the muscle, (as for instance in the kidneys;)
many of them may be observed in the same situation,
and it is then readily perceived that they are not all
equally active; for some possess all their cilia, whilst
others have lost them, and in consequence remain quiet,
or are seen to be adherent, and their substance has become
parenchymatous. ‘There are also met with, especially in
the muscles inhabited by these Paramecia, other more
parenchymatous, and more or less regularly oval bodies,
which are slightly depressed and adherent. It is not
difficult, among the numbers which are usually present,
to show the complete change in every respect of these

THE TREMATODA. 91

oval bodies mto the adherent, sluggish Paramecia, so
that I have been unable to distinguish between them, and
I consequently see in the whole series of changes, only
the passage towards the metamorphosis of the ciliated
animaleulae into motionless parenchymatous bodies. Al-
though motionless, they must not be considered as life-
less, since their continued growth may be readily fol-
lowed, and is evidently the effect of nutrition, and not
an expansion caused by the substance distending them
from within. From a length of #5” they frequently
attam that of #5”; and the size of a transparent spot —
indicating a amie increases in the same alee
When the animalcules have attained the size of 35” their
internal cavity is evidently filled with minute ol or
spherical corpuscles, which are germs, and which now
commence a remarkable development. As the animal-
cules increase in size, they become more and more paren-
chymatous and friable, and their external substance is
broken by the slightest pressure, nothing remaining then
but a strong internal membrane which incloses the cavity
in which the germs are contained. This rupture occurs
especially when they have attamed their full size of 2” or
even of 1’, at which time the largest of the successively
developed embryos have acquired the length of 35” and
he inclosed merely by a saccular integument, in write the
metamorphosed Paramecium-like animalcule is scarcely
any longer recognizable.

The included embryos, which, like the Cercarie or
their “‘ zurses,” occur in all stages of development within
the sac, present usually a short neck-like prolongation at
one end, and on the other a distinct depression, which
may probably be an oral orifice or suctorial organ, by
which they can affix themselves when they have in some
way or other, most likely by bursting it, escaped from
the sac; they are then found of the size mentioned above
(5) in the internal organs of the muscles. If some of
these embryos extracted from the sac or newly escaped
from it are allowed to rotate on their axis, under the mi-

92 DEVELOPMENT OF

croscope, it will be seen that their transverse section is
perfectly circular or very slightly depressed, and that their
integument, and, it might almost be said, their whole
substance, is composed of amass of regular, nearly equal-
sized, closely packed, globular cells or vesicles, (gland-
follicles P); and that this substance incloses an internal
cavity of nearly the same shape as the body externally.
In this cavity a series of globular germs is distinguish-
able, and as the body in which they are contained
which though motionless is yet living, increases in size,
until it is more than a line in length, these germs also
increase and become active cercaria-like creatures, that is
to say animalcules with a distoma-like body, and a lon

moveable tail; but the tail in this instance is both thick
and clavate, and the fully-developed animal is the Dis-
toma duplicatum of Baer.*

The course of development of these Cercarie within
the parent receptacle, corresponds entirely with that of
the true Cercarıe, and after quitting their “ nurses” it
would appear that they necessarily undergo also the same
change as those, as they shortly afterwards cast off the
thick tail, and move about as Distomata ; but it has hap-
pened to me as it did to Baer, that they died before
becoming pape, notwithstanding which, however, I have
no doubt at all that they do enter into that state, but
probably only under peculiarly favorable circumstances.
As multitudes of these Cercarie occur in many muscles
within their sacculi, and also occasionally out of them,
and as they are sometimes present in some, and even in
many muscles by many thousands, it might be expected
that they would be met with plentifully in the form which
they finally assume. This is not the case however, and
although Baer and several others have examined the
muscles with great care in order to find entozoa, no true
distoma has been discovered in them; we are made ac-

* Baer’s memoir upon Distoma duplicatum will be found in the series of
his other memoirs upon the Cercarie and other entozoa, including Planaria,
in ‘Nov. Act. Acad. Leop. Car, Natur. Curios.’ xiii, tab. 28.

THE TREMATODA. 93

quainted, however, by the researches of Baer with a
remarkable entozoon of the Distoma family, Aspidogaster
conchicola which occurs only in the ventricle of these
molluscs. Upon comparing the form of this worm with
that of the body of the distoma-larva with clavate tail, I
cannot help supposing, from what I know of the change
consequent upon metamorphosis in this family, that the
D. duplicatum of Baer is the larva of Aspidogaster con-
chicola (Baer.) There is certainly a remarkable discre-
pancy between this view and the fact that Baer has found
only one or extremely few specimens of Aspidogaster in
each muscle, whilst on the contrary the animals from
which I suppose them to proceed, occur by hundreds and
thousands in each individual ; this only proves, however,
that certain favorable conditions are pre-requisite for the
complete development of the entozoon, and how much
nature compensates by an inexhaustible fertility, for the
mevitable loss sustamed in consequence of the absence
of such favorable conditions. This discrepancy, more-
over, is not greater than that which exists in the case of
the Cercaria echinata, of which many thousands have
been observed, while it seems that the full-grown Disto-
mata have been noticed only in the few individuals men-
tioned above.

Whether my supposition, that the Cercaria (Distoma
duplicatum Baer) is changed into Aspidogaster conchicola
(Baer) be correct or not, still it is certainly a Zarval form,
and derives its origin in the ¢hird remove from a ciliated,
free-swimming animalcule, which is afterwards metamor-
phosed into a sacciform “nursing animal,” which, in
accordance with the terms used before, must be called
a “ parent-nurse” (grossamme) ; whilst the progeny deve-
loped in it, which, from their absolute and relative size, and
their possessing a cavity containing germs, can in no wise
be Cercarie, constitute evidently the same step in develop-
ment, as the true “ zwrses,” and from which is produced
the next step in the series, the D. duplicatum, which can
only be compared with a true Cercaria; which in fact it is.

94 DEVELOPMENT OF

(d) Tue DEVELOPMENT OF OTHER TREMATODE ANIMALS.

Thus, if we trace the ciliated frematode embryos in
their progress towards a perfect Zrematode, or if we
proceed in the other direction and go back from the
Trematode itself, and endeavour to get as near as possible
to its origin, the same phenomena will be presented to us,
since the species must, from the egg upwards, necessarily
pass through several generations succeeding each other in
a definite order before it appears as individuals, which
both externally and internally resemble those from which
the course of development commenced, and which are
capable of propagating the species anew by the genera-
tion of ova. That all ¢rematode animals are developed in
this way, that all are obliged to undergo such alternation
of generation cannot be directly affirmed from the facts
adduced ; these, however, are sufficient to warrant the
supposition that this is probably the case. I will here
only recall the general observation made with regard to
the ova of the Zrematoda, that there always proceeds
from them a more or less active ciliated animalcule which
has not the slightest resemblance to the parent animal,
and consequently, under all circumstances, must undergo
a remarkable change or metamorphosis. It might, on
this account, with great probability be assumed, that its
progress and course of development corresponded with
those of similar creatures, and that it was metamorphosed
into a ‘nursing’ individual, as is shown by Siebold’s
observations on Monostoma mutabile, and mine upon
Distoma duplicatum. If such a course of development
be supposed, there must be as many forms of “nurses’” as
there are species of Zrematoda, and since such “ nursing’
animals have not been observed, it would certainly be
extraordinary that all the search after entozoa, which has
been made, should not have brought to light animals,

THE TREMATODA. 95

which might with some probability be supposed to play
that part; I must, however, remark upon this, that no
search has as yet been made for them with this view.
Secondly, that they may occur in such situations and
under such forms as would be least imagined; and,
lastly, that they may have remained concealed by their
extreme minuteness. It should be remembered that the
““ nurse’ of the Medusa, Oyanea capillata is only a few
lines long, and remains at the bottom of the sea, while
the full-grown C. capillata which has been indebted to it
for its nourishment, is a million times larger, often spans
a space of several fathoms, with its tentacula, and swims
about freely in the ocean.

There are not wanting, however, farther examples of
the occurrence of the same mode of development in other
Trematoda, besides those related in the above observa-
tions. In Baer’s memoir, so often quoted, we meet with
mention of several, sometimes lifeless, (that is, motion-
less,) sometimes living, “ germ-sacs’’ containing Cercarie
in all stages of development, and which, consequently, I
am obliged to look upon as so many species of “ zwrses.””
Here belong also the cysts or so-called Aydatids in which
Baer found completely developed Distomata ; as for in-
stance, D. cirrigerum in hydatids in the muscular sub-
stance of our common river crab (Astacus fluviatilis,)
another Distoma in our smallest fresh-water snail (Ancy-
lus lacustris,) and lastly, one which inhabits an active
“germ-sac, resembling the “ nurses’ of C. echinata, but
like those of C. ephemera, wanting the lateral processes.
The extraordinary entozoon Leucochloridium paradoxum
found by Carus in the swollen tactile horns of Succinea
amphibia, and in which there were numerous developed
Distomata, is also only a “nurse.” I cannot therefore
agree in the opinion of that mgenious naturalist, that it
might have originated by equivocal generation from the
metamorphosed cellular tissue of the mollusc; I even
believe that I have discovered its true origin, in finding in
the tentacles of this snail in the early months of summer,

96 DEVELOPMENT OF

some oval, very active, ciliated animalcules, which were
not unlike the Opalina ranarum of Ehrenberg.*

The Distomata thus undergo their complete metamor-
phosis within these last-mentioned “ nursing animals,” as
is the case with that Distoma which, as we have seen,
results from the larva of Cercaria armata when it has not
had the opportunity of quitting the “ zurse’” at the proper
time. Consequently, when the larvee of this species are
not destined to swim about freely, we cannot expect that
they should have the form of a Cercaria, that is, that
they should be provided with the tac/, which is the prin-
cipal swimming organ of those creatures, and thus the
larvee of the different species of Distomata which mhabit
the interior of the allied fresh-water snails, would even
not have that form ; still less should we expect that the
Distomata of other classes of animals should have it, and
we may even with greater probability suppose, that the
cercaria-form will be found only in the Distomata of the
snails, since, at present, the Cercari@ have been observed
only in water, in which fresh-water snails have been. +

I must here, however, refer to an observation which
although it proves nothing respecting the alternate gene-
ration of the Zrematoda, yet makes us at least acquamted
with an interesting metamorphosis which some of the
forms undergo, and shows us where, in all probability,
the Zarve and pupe of a whole genus of Trematoda are to
be sought for. Nordmann’s discovery of the occurrence
of entozoa, and especially of those belonging to the ¢re-
matode family in the eyes of fish, particularly of fresh-
water fish, in such numbers that their presence in these
delicate organs may almost be considered as normal,
caused at first, as might be expected, great astonishment,

* An animal which swarms in the rectum of the frog in thousands, pro-
bably to the end that one of the many may reach a situation favorable to
the development and propagation of the species. Baer’s Baucephalus poly-
morphus is probably also to be here considered a “ »ursing” animal.

T Aproof that entozoa may enter animals which they do not usually infest,
is derived from this,—that I have once found the pupa of Cercaria echinata
on the heart of an Anadonta.

THE TREMATODA. 97

but the fact is now as generally recognized, as it is readily
proved.

Thus it is not at all wonderful that I should also have
found numerous Zrematode animalcules in the eyes of
our fresh-water fishes ; but it was very instructive that I
should meet with two of these Zrematode forms in the
eyes of the pike and perch, which differed in size and ap-
pearance, but nevertheless were so much alike externally
and internally, that I could scarcely doubt that they
belonged to the same species, and that the one was
an earlier condition of the other ; besides these, I found
sometimes in the same, sometimes in other eyes, situate
here and there, minute watch-glass-shaped capsules,
which inclosed Zrematode animalcules resembling both
forms, but especially the larger, and examination soon
rendered it certain that this was the pupa state, inter-
vening between the two forms noticed. This interested
me so much the more, that I sometimes found these
pupe on the internal surface of the cornea, and at the
same time noticed a finely granular, unorganized streak,
which passing through the cornea to the pupa clearly in-
dicated the way by which the animal had penetrated
_ previous to becoming a pupa. That these animals had
entered from without, was shown also by some pupe
which were situated in the skin around the eye, or a little
beneath it, or even on the muscles of the globe, (and in
this situation, the pwpe doubtless correspond with the
encysted parasites, whose occurrence on the muscles is
mentioned by Prof. J. Müller, in his memoir on the
Psorospermata.)

I was surprised that I could not recollect, that
Nordmann had remarked this form of development, but
when I afterwards obtained his celebrated work,* I saw
that he was well acquainted with, and had described and
figured it all, but only that this interconnexion between
them was unknown to him. Two of the forms, for in-

* A. v. Nordmann, Mikrographische Beiträge zur Naturgeschichte der
wirbellosen Thiere. Berlin, 1832, 4to.
7

98 DEVELOPMENT OF

stance, represented the two divisions of his genus Dr-
plostomum, and the third, that of Holostomum ; so that
his Diplostomum clavatum is the larva, Holostomum cu-
ticola* the pupa, and Diplostomum volvens the full-grown
Trematode.

Now since we see (1. c.) that Nordmann has observed
fifty-eight species of entozoa in the eyes of different fish,
which belong principally to the two genera named Ho/os-
tomum and Diplostomum, and that he has formed two
separate groups of the latter genus, the one claviform,
corresponding with D. clavatum, and the other broader and
flatter, with D. volvens, I am certamly much inclined to
assume that the one group is the /arva condition of the
other ; and Nordmann’s own words appear to support me
in this supposition, since he was himself inclined to con-
sider them to be connected as younger and older forms, if
only the transition form between them had been discovered.
We cannot expect to meet with such if a pupa state forms
the intermediate link, and on this account we may pre-
liminarily regard the encysted Zolostomum as a pupa.
According to the remark, p. 102, it appears that most, if
not all Holostomata in fishes are thus encysted, and con-
sequently that they are pupe. Now if we assume, as our
present knowledge would seem to justify us in doing, that
these forms (of Distoma) are peculiar to the eyes of fish,
as they have not been observed in other organs, and if we
allow its proper weight to Nordmann’s observation that
the pupe or encysted Holostomata are frequently found
over the whole skin of the fish, either immediately under
the epidermis, or imbedded in the most external layer of
muscle, we shall again perceive a ready explanation of the
fact that many of these animals must necessarily fail of
being developed even though they have reached the or-
ganism at the expense of which they are destined to live,

* In his description, the Holostomum cuticola is represented as of a larger
size than my pupae, but the form is the same. Holostomum brevicaudatum of
Nordmann, which was not found in a capsule, much resembles an individual
which has just quitted the pupa case, and remains in a contracted state; its
size corresponds exactly with this.

THE TREMATODA. 99

unless they also reach the organ or situation, which af-
fords the requisite conditions for their future development.
There is no doubt at all from what precedes, that another
animalcule described and figured by Nordmann is also a
pupa, viz., the Distoma annuligerum, (tab. 1, figs. 5, 10 ;)
it also inhabits the eye of the perch, but Nordmann has
invariably found it only in the pupa state.

Having thus, as I hope, shown in what way /rematode
animalcules also enter fish from without, and penetrate
into their organs, and immediately as it seems whilst
undergomg a metamorphosis, I will now only add an
observation which renders it probable, that the Zrematoda
of the higher animals, at least of the Batrachians, likewise
make their entrance into them from without ; I have, for
instance, found immediately under the skin of the common
frog (Rana temporaria) small cysts, which from my pre-
vious knowledge of the transformation of the entozoa, I
necessarily considered as pupe, and the correctness of
this supposition was established when I opened them ;
for they invariably contained a frematode animal, viz.,
an Amphistomum, ‘and since similar entozoa are rather
frequently met with in the rectum (4. clavatum,) and I
usually observed the pupe@ on the mesentery, and even in
the cellular tissue surrounding the intestinal canal, I was
obliged to conclude that the mdividuals within the intes-
tme originated in those pwpe, and had entered through
the integument. It will not, however, be long before
observation will prove it to be a universal fact, that the
greatest part of these parasites penetrate through the skin
by the shortest route into the internal organs.

When a metamorphosis occurs so extensively, or is even
universal in one division of the entozoa, the question
naturally arises, whether with respect to the other divi-
sions of that class, it is probable that a similar trans-
formation is effected by a single metamorphosis, or

100 DEVELOPMENT OF

whether even they probably do not attain their development
through a series of alternate generations, and exist at first
externally to the organisms with which their life is after-
wards inseparably connected. Although I cannot commit
myself to a precise reply to this query which is rather
beside the especial object of these pages, yet I cannot help
giving a few hints on the subject. The Nematoidea,
which in their adult state often pass from one individual
to another, also probably penetrate from without and as
embryos, the organısm they infest; they do not appear
to undergo a true metamorphosis, but to change their
skin: I am also unacquainted with any observation which
would justify the supposition, that there is in this group
any fostering of the young by precedent generations,
unless the genus Spherularia, a parasite of the Hymenop-
tera, which Siebold refers to this division of entozoa be a
‘nurse’; at least it much resembles one, appears to be
nearly powerless to perform spontaneous movements, and
contains a numerous smooth-skinned progeny, which move
about very actively within their parent, but bear no re-
semblance to it.* The cystic entozoa on the contrary,
betray in many ways that they are a “ xwrsing” genera-
tion, and especially in the singular circumstance of their
being frequently inclosed like boxes one within the other.
Probably the full-grown animal of this division is quite
unknown, and it is not unlikely, that in course of time,
it may happen with them as it has with the whole division
of the “ asexual” 'Trematoda of Siebold, viz., Cercaria,
Leucochloridium, &e., that they must be rejected from
the system as being earlier forms of development, or
earlier generations of other animals. The Zehinorhynchi
present several phenomena which are interesting with

regard to our object, viz., the remarkable incubation or

* See Siebold’s Abh. von d. geschlechtsl. Nematoiden, in Wiegmann’s
Arch. 1838, B. iv, h. 1, s. 305. Further researches will show the nature
of the so-called asexual Nematoidea which inhabit cases or cysts; they inspire
the more interest since Creplin, in his remark upon Siebold’s memoir, referred
to above (Wiegmann’s Arch. 1838, B. iv, s. 373,) alleges that there is no
known instance of the encysted Nematoidea possessing sexual organs.

——_

THE TREMATODA. 101

breeding which takes place between the skin and the
viscera, and the inclusion and incipient development of
the ova in the so-called “ /oose ovaries,” during the con-
tinued growth of the latter. I must confess, that I look
upon these oval bodies much rather as individuals which
will never quit the parent animal, than as “ovaries; and
till their true nature is known I shall regard them as
such, and consequently consider most of the Zehinorhynchi
hitherto known, as “nurses.” It is confessedly uncertain
whether the Zehinorhynchi spend part of their life exter-
nally to the organism which they inhabit as full-grown
animals, or not; it is however very probable they do so,
as the embryo attains no real development in the ova
so long as these are in the Hehinorhynchus ; and the ova
are met with in the mucus of the stomach and in the
excrements, by thousands, in the same condition, so that
the development of the young in the ova and their escape
from them, certainly occurs very long after the ova have
reached the water.”

With this I connect the remark, that in the months of
February, March, and April, I have often found in the
mesentery and cellular tissue about the liver and intes-
tine of the sole, very minute individuals of from 4 "— 3"
or sometimes even 1”” in length, a// of which were inclosed
in a thick membranous cyst, of a more or less regular
oval form. When these cysts were opened (fig. a, tab. ii)
there came out of them a very much contracted Zehino-
rhynchus (fig. 6) whose organ of attachment, furnished

* A remarkable exception must be made, however, in the case of a species
of Echinorhynchus examıned by Professor Eschricht, and in which he observed
innumerable ova, in which the embryo was so much developed, that at first
the egg membrane escaped his notice, and he believed the embryos had been
hatched. As this observation was made on an Kchinorhynchus of the common
haddock of Copenhagen, and as the Zehinorhynchi of this fish, as well as of the
sole, which appear to be the same species, have been examined by many, it
is the more remarkable that this condition was not earlier noticed; I have
myself, during several months, examined the Zehinorhynchi of our common
sole, but there has been no trace of an embryo in their ova, although the
latter were passed by thousands in the exerement. [May it not then probably
have been an ascaris or some other nematode which Professor Eschricht had
before him ?]

102 DEVELOPMENT OF

with hooks, was deeply retracted within the animal, and
which after some time it began to extend,- and finally
protruded as its armed proboscis (fig. ce.) Whether the
animal lay in this cyst as in a sort of pupa condition, I
I must leave undetermined, but such appeared to be the
case. ‘This observation corroborates the opinion of Prof.
Eschricht, that the Hchinorhynchi probably penetrate the
fish; for he found m the summer months, in the flesh
of the Copenhagen haddocks numerous Lchinorhynchi
which he could only regard as young ones, in the act of
passing through the skin and flesh to the intestmal canal,
their proper abode, and in which situation only, are they
met with, as adult, or nearly adult individuals, so that
the helminthologist Siebold has never yet met with
Echinorhyncht so young, that the so-called “ loose ovaries”
were not developed in them, and has never even met with
individuals which he could altogether call “ smadl,”* on
which account the encysted individuals mentioned above
as occurring in the abdominal cavity, are not without
interest.

Lastly, with respect to the metamorphosis of the
Cestoid worms, we have an example of it presented to
us in Miescher’s interesting memoirf on the forms which

* Vide Burdach’s Physiologie, 2d edit. tom. ii.

+ Lam acquainted with this memoir only through the reference to it made
by Siebold in the Report of Contributions in the province of Helminthology
during the year 1840, given in Erichson’s Archiv, 1841, s. 301-304; but
I must remark, that it is rather bold to assume that the encysted Filarie
piscium are transformed into claviform cysts, wherein is found at first a
trematode animal, which is afterwards developed into a Tetrarhynchus.. These
encysted Filarie piscium, which occur so abundantly in the haddock, &e., and
whose description by Siebold has already been once mentioned in this memoir,
betray, as it appears to me, but very little similarity with the at first tubular,
afterwards clavate cysts which I have found loose in the abdominal cavity
and on the viscera of Hsox belone, and within which there is always a Ze-
trarhynchus, with spirally contracted hooked tentacles, capable of being ex-
tended to an extraordinary length. The earlier condition, so far as I have
been able to judge of the Zube, certainly has the form, but none of the struc-
ture of a Pilaria. The contracted animal inclosed in the knob-like cysts in
which the Zetrarhynchus is developed, resembles, as far as its substance is
concerned, a very young cestoid embryo. All the developed Tetrarhynchi
within the cysts had the appendix to their bodies which is mentioned by
Miescher as being present in those which he met with in the cavity of

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THE TREMATODA. 103 —

the genus Zetrarhynchus passes through ; but which also
in fact includes nearly all we know about them; whilst
the great work of Professor Eschricht, upon the genus
Bothriocephalus of this family, has given an entirely new
view of those animals, constituted of almost innumerable
jomts, so that they are to be regarded according to his
anatomical investigations, not as single but as compound
animals, viz., compound Zrematoda or flukes, so that each
jomt is to be compared with a distoma,—a view of their
nature to which Baer had some time before alluded, and
which had also struck Creplin and Mehlis, on account of
the resemblance of the sexual organs, but which is now
for the first time entitled to the greatest attention, having
been rendered probable by so many anatomical researches.
However, I cannot for my part entirely coincide in this
view of the Cestord family of worms, for in whatever way
the jomts and thei reciprocal connexion are considered,
compound animals are presented, whose construction is
entirely different from that of all other animals. The
tapeworm is certainly not a single individual, but con-
sists of several; that is, it 1s constituted of the head,
which is an animal, and of the progeny derived from it.
This view is much supported, it is even proved by the
fact, that the offspring (jomts) m a state of progressive

development, never actually become animals similar to
that from which they spring (the cephalic joint,) which
alone remains dissimilar to all the rest, never acquires any
developed sexual organs, and consequently never generates
any ova, which the others produce in great abundance ;

whilst the cephalic jomt is furnished with a mouth and
suctorial acetabula, proceeds from an egg, and is the
animal upon which the development of all the rest de-
pends, and is thus in fact one of those animals to which
we have in the preceding pages given the name of “ nurse.”
the thorax and around the heart, and which in his opinion were on their
migration to the exterior of the animal, (might they not rather be on their
migration to the intestinal canal within ?) For the rest, I must lament that
other occupations prevented my availing myself of the opportunity which

was afforded me of making more accurate researches into the dev elopment of
the Tetrarhyncht.

104 DEVELOPMENT OF THE TREMATODA.

If this view be correct, which time will determine, it will be
seen that the Bothriocephali, just as all the other animals
mentioned in this Hssay, which are developed through
alternating generations, present quite another and more
significant resemblance to plants, than that set up by Prof.
Eschricht. The individuals which are fostered by, and
appear to proceed from the head by the so-called trans-
verse division,* thus attain such a degree of perfection,
that the ova are fully formed in them even before they
become detached from the “ nursing animal”; and, as
defensive cases for the ova, they are passed in the natural
way from the animal which they have infested, in order
probably to reach, eventually, another similar animal,
under another form, and as other individuals.t

* The head of the Bothriocephalus, with all its successive joints, appears
to me aptly comparable with the Scyphistoma strobila ; but no one has as yet
termed that a compound animal, nor has the term been applied to the
connected series of Nada, although their condition is a very similar one. It
has been said of all three forms, that they are multiplied by transverse
scission or division, expressions which I should not venture to use without
prefixing “the so-called,” for the relations which obtain in these instances
are entirely different from those which would be implied by the separation or
abscission of a definite portion of a whole from the other portions of the same
whole, in order that the separated portion should itself become another
similar whole. I have never been able to meet with Naide so small, but
that it was quite evident that several individuals, in various stages of develop-
ment, were ranged one after the other, and that the one animal was never
developed from jomts which had previously belonged to another individual.

T The development which the ova of the CesZoidea undergo must obviously
occur under very peculiar circumstances. Professor Eschricht remarks upon
this subject, that the ova, collected into masses and encased in a thick
slime or mucus, are passed from the joints packed up, as if they had to
make a long and difficult journey. I was also much surprised to see the
separate jomts of the tapeworm of the sheep and dog passed, each by itself,
with the ova, and as it were in a definite proportion with the evacuated
feeces ; in alamb which was much infested with this worm, I was even struck
by the regularity with which each jomt of the worm passed through the
rectum with four or five balls of the feeces, so that I necessarily concluded
that the object of these little masses was probably not merely the conducing
to the development of the germ in the ovum, but also to the transference of
the embryo to new organisms. As matters stand also, I cannot doubt that
the Entozoa in certain stages of their growth, or in certain generations, have
a geographical extent and distribution im nature (e. g. in water) externally to
the organisms which they infest at other times. We could not otherwise
easily imagine how the Entozoa of man or of domestic animals, especially in
plete Paes should occur as they do, dispersed in regions far remote from
each other,

105

CHAPTER V.

CONCLUDING REMARKS ON THE ALTERNATING GENERA-
TIONS AND THEIR REAL NATURE.

Tue mode of development by means of “ zurses” or
intermediate generations, is thus seen to be no longer an
isolated phenomenon in nature. The circumstance of an
animal giving birth to a progeny permanently dissimilar
to its parent, but which itself produces a new generation,
which either itself or in <Zs offspring, returns to the form
of the parent animal, is a phenomenon not confined to a
single class or series of animals ; the vertebrate class is
the only one in which it has not yet been observed.* It
would consequently appear that there is something in-
trinsic in this mode of development, and that it occurs as
it were with a certain necessity ; on which account it will
undoubtedly soon be recognized to a greater extent and
more generally. It should no longer be considered as
something paradoxical or anomalous (as we have hitherto
been too much inclined to deem both it and the pheno-
mena in which it is exhibited,) it must be in harmony with
the rest of development in nature, in which the funda-
mental principle of this course of development must also
be elsewhere expressed, although it may be displayed
in a form under which we shall less readily perceive and
recognize it. This is seen when we trace the mode of

* To the instances adduced in the foregoing pages, we might add the
- eyclical development of the vorticelle, as it. has been described by Ehrenberg.

106 THE ALTERNATING GENERATIONS

development in question more widely through nature ; and
whilst contemplating it through the phenomena in which
it is manifested, we comprehend it in its true light.

If we collect and regard in one view, the whole
system of development by means of “ nursing” genera-
tions, as it is exhibited in the dell-shaped Polypes (Cam-
panularia,) the Claviform Polypes (Coryne,) Meduse,
Salpe, Vorticelle, and Entozoa, it appears as a peculiar
and consequently as an essential feature in this course of
development, that the species (that is, the species m its
development) is not wholly represented in the solitary,
full-grown, fertile individuals of both sexes, nor in their
development, but that to complete this representation,
supplementary individuals, as it were, of one or of several
precedent generations are requisite. Thus, the distinction
between this course of development, and that which is
generally recognized in nature, in which the species is
represented by the individual (of both sexes) and its de-
velopment, is the want on the part of the individuals of a
complete individuality as representatives of the species,
or of a specific individuality, if I may so express it. If
now we agree to regard such an incompleteness in the
mdividual, as the essence of this development, we
shall comprehend its significance in nature when we
thoroughly consider this course of development in zfs
various periods, throughout the above-mentioned families,
how it begins and advances, so that at last we discover
to what it tends. I believe also, that we might trace,
even now, this development by means of precedent, pre-
paratory generations of “ zwrses” in its peculiar course and
advance, notwithstanding the paucity of instances adduced
im the foregomg pages, and the many gaps im the series
of observations. ‘Thus we see the greatest mcompleteness
and the highest degree of mutual dependence in the ~
Campanularie and similar polypes, in which the genera-
tions representing the unity of the species are very unlike
each other, and in which all the individuals, are fused as
it were into an outward unity, or into a set of polypes., °

AND THEIR REAL NATURE. 107

They exist, organically connected with each other, and are
normally free only in their first generation, and indeed
only in their earliest stage of development, and only for
a short time, since the free-swimming ciliated embryo
swims about in the water at most for some hours, in order
to find a suitable place for the foundation of a new polype
stem. In the Coryne or claviform polypes, the organic
connexion between the individuals and generations is
rather more lax; the perfect gemmiparous or ovigerous
individuals are usually quite free, often even at an early
age (Coryne fritillaria, Corymorpha,) so that they do
not attain their full development until after their separa-
tion from the “ »ursing”-generation. In the Meduse and
Salpe, the generations which are connected together into
one whole, become more like each other; the first gene-
ration of the Meduse is still fixed but more active and
mobile in its parts; the individuals of the perfect genera-
tion, leave the “ zursing” animal while still very small, and
undergo remarkable changes after they have become free
and are swimming freely about ; both generations of the
Salpe, finally, are free and free swimmers, only the indi-
viduals of one of them are organically connected with
each other; they have, however, no common organs (in
the full-grown state,) and if my explanation of the alter-
nate generation of the compound Ascidians is correct, we
have in that instance precisely the development of the
Salpe at a somewhat lower stage ; the individuals of the
one generation are organically connected, without having
a common organ ; but both generations are fixed.

In the class of Zntozoa a similar progressive attempt at
becoming free and accomplishing a perfect growth appears
evident to me.

In the Cestoidea the generation of perfect individuals,
constitutes externally a unity ; they are only successively
detached from each other as the term of their existence
approaches, and their whole existence is throughout con-
nected with the “ zursing” animal. In some of the Zre-
matoda, the later generations remain within the earlier,

108 THE ALTERNATING GENERATIONS

until they have attained their full development ; in others
they forsake them in an earlier condition, are free and
free swimming, and undergo a complete metamorphosis ;
in some of these latter, the earlier generations are trans-
formed into motionless and as it were lifeless cysts, whilst
in others, they remain free and active, (the “ nurses’’ and
““ parent nurses’ of Cercaria ephemera and C. echinata,)
but retam during their whole life a form, which, at most,
resembles the larva of the more perfect generation. In
this way an advance in a certain direction, may indis-
putably be observed ; at first, all the generations consti-
tute a unity, not merely as regards the interior, but also
with respect to the exterior; they form a stationary
colony ; after which, the generations are detached more
and more from each other, and become at the same. time
more free ; and finally, all the individuals constituting the
generation are separate from each other, and acquire the
power of free locomotion ; in this latter stage, or that of
freedom and perfection, we found the development of
animals which are certainly no longer attached to inanimate
objects at the bottom of the sea, but live buried in other
animal organisms, and belong not to the sea, but to fresh
water. Ina still higher and more free stage than this, we
observe the development of animals, which do not belong
to the water, but to the air, as in that which occurs in the
Aphides. The propagation of these creatures through a
series of generations has been already long known. In the
spring, for instance, a generation is produced from the ova,
which grows and is metamorphosed, and without previous
fertilization, gives birth to a new generation, and this
again to a third, and so on, for ten or twelve weeks; so
that in certain species, even as many as nine, such pre-
limimary generations will have been observed ; but, at last,
there always occurs a generation consisting of males and
females, the former of which, after their metamorphosis,
are usually winged ; fertilization and the depositing of
eggs takes place, and the long series of generations re-
commences in the next year, and in the same order. All

AND THEIR REAL NATURE. 109

the individuals are free and enjoy the power of free loco-
motion, and undergo a metamorphosis; here, however,
we have before us aerial animals, and which are no longer
parasites inhabiting other organisms; at most they are
only externally parasitic, and on plants alone; the phe-
nomena of this mode of development are no longer
exhibited by Zntozoa, but by Epiphyta. Nevertheless,
the course of development is in itself similar ; but in the
external, more free, and nobler form in which it is now
exhibited, the endeavour to attain something higher is
manifest; each lnk or generation certainly brings its off-
sprmg nearer to the perfection aimed at; but this ap-
proachment towards perfection is effected only by means
of the “ nursing” by special animals, and is committed —
to the still and quiet activity of an organ, without the

nursing animals themselves being conscious of it; it is a
function merely and not an expression of the will. In
all parts of the animal kmgdom we see instances of the
still, quiet, and unconscious activity of the animal, being
developed into voluntary actions, which are undertaken
by it from an internal, obscure, and irresistible impulse
(or artificial impulse,*) as is the case in this instance.
The development and mode of feeding or nourishing the
young exhibited in its course, of Bees, Wasps, Ants, and
Termites affords a direct example of the mode in which the
care of the young is provided for, by the voluntary action
of numerous individuals devoted to that object. Those
of the young which are to be developed into the more
perfect, fertile individuals, are not protected in the body
of the foster-parents, nor is their nourishment secreted by
one of their organs ; both protection and food are afforded
them by means which are brought about by the conscious
activity of the “feeders.” The wasp, for instance, or the
wild humble bee, which has been impregnated in the
autumn and has afterwards sought a shelter to protect
itself against the cold of winter, prepares a solitary habita-

en Or instinct to produce compound effects resembling human art (Kunst-
trieb.)

110 THE ALTERNATING GENERATIONS

tion, in which it builds cells and deposits its eggs ; from
the eggs proceed /arve, but the msects into which these
larve are metamorphosed are not fertile; they are barren,
and all their faculties are directed to the assisting of the
parent animal in the better nourishing of the future
brood, to which end, some of their external organs are
transformed, and to the erection of a better habitation and
cells into which they convey the eggs of the female, and
the food of the /arve to be developed from them. Other
cells, which contain a better sort of food, are erected for
a later and less numerous progeny of eggs; and again in
others, which are more roomy and provided with the best
kind of food, but of which there are only a few, is the
last brood of the female deposited. From the first kind
of cells, proceed the barren individuals, from the second
the males, and from the third the females; after under-
going a metamorphosis, the males and females fly away,
impregnation takes place and the males die ; the females,
however, return, and the whole multitude of barren indi-
viduals, which at the same time perform the duty of
feeding the young, build cells for their various progeny of
eggs, and nourish the three forms of larv which proceed
from them. In this way the inhabitants of the colony
become very numerous; nevertheless they all die off in
the winter ; the fertile females alone remain alive, and
propagate the species the year following, under the same
development of alternating broods, the earlier of which is
always by far the most numerous, and assists in the
development of the later. In the colonies of Bees, Ants,
and Termites, the same thing occurs ; the many thousand
individuals which constitute one of these colonies, are
principally “ feeders,” or individuals which have origin-
ated in the precedent divisions of the eggs of the females,
and in these is exhibited, even with greater precision, a
more marked division of labour in the feeding of the
progeny. So that, out of the various precedent divisions,
individuals apparently arise which assist in the develop-
ment of the more perfect progeny in various ways. ‘Thus

AND THEIR REAL NATURE. LEE

there are in a hive of bees, individuals which are em-
ployed almost wholly in the feeding of the larvee (Füt-
ferer, foragers,) whilst others do scarcely anything else
than collect wax and build cells (workers.) Im anthills,
one set of the feeders is constantly employed m conveying
the larvee from one place to another, according as they
require a greater or less degree of warmth, &c., whilst
others are engaged in building the passages or earth cells,
and in making excavations around the habitation. Among
the Termites also we are acquainted with several forms of
“ feeders,’ constituting particular tribes or classes ; the
description of labour however, which each of these classes
performs, is unknown ; it is known, however, that a form
with a large head and strong jaws, is always posted at
the entrance of the artificially constructed dwelling, and
keeps guard there as soon as any disturbance is remarked,
and thus constitutes the safeguard not only of the young
but of the whole community.

Now, in the cases m which the more perfect develop-
ment of the progeny is promoted,. either by means of
“ nurses’ * or of “ feeders,’ + (under which latter term,
we understand special individuals devoted to the actual
care or nourishing .of the young, which office they fulfil
by a conscious activity,) we see that nature always has
im view the production of a multitude of mdividuals
to whose life or care is then committed the perfect-
ing of a later generation or progeny, consisting of less
numerous individuals. This previous or preparatory
multitude seems to consist, mvariably, of females, the
males being apparently excluded from any participation
in the office, on which account the males of all the
animals among which the system of “nursing” or of
““ feeding’ obtains, constitute a very subordinate number.
That the “nursing” should be committed to females
alone appears to us very natural, since we are acquainted
with an organ in them whose natural function would be

* The “nurses” (amme.) + The “feeders” (pflegerinne.)

112 THE ALTERNATING GENERATIONS

to perform that office. The generative organs are, indeed,
in perfect (female) individuals, divided as it were into
two parts of very distinct natures; the ovariwm for the
preparation of the germ and the production of the egg,
and the oviduct and uterus in which the ova are as it were
incubated, and the germ and embryo sufficiently
developed to allow of its bemg born. Now, it is actually
the case, that no true ovary has been discovered in the
“nursing (ammen) generations; on the contrary, the
germs, as soon as they are perceptible, are situated in
organs which must be regarded as oviducts and uteri, as
for imstance, m the most perfect “nurses” we are
acquainted with, the Aphides. In the “ nurses’ of the
trematode larva, Cercaria echinata, 1 have remarked,
that the germs in their earliest condition, are collected
into an organ at the root of the tail, which may pro-
bably be regarded as a uterus, and that they appear to
distend this organ gradually to the size of the whole body.
The accurate anatomical researches of Prof. Eschricht on
the Salpe, also show in the most precise way, that the
associated brood of the Sadpe does not originate from ova,
but that, as germs which are arranged in a definite
manner between the walls of a hollow organ, it is con-
tained in what can in no case be an ovary, and which the
author has termed a ‘‘ germ-tube,’ (Keimrohre.) This
organ lies in a cavity which may probably be considered
very nearly a wterus, which is however, always as it were
a secondary receptacle for the germs; but in the present
instance, it cannot be shown that they have occupied any
previous receptacle or place of formation.*

From what we at present know, we may probably

* Accurate researches with respect to these organs of the “»urses” in all
the above-mentioned forms of animals, such as have lately been made by
Professor Eschricht on the Salpe, would be of extreme interest for the
physiology of generation, and would be a task worthy of a competent anato-
Be I cannot refrain from again directing attention to the remarkable

an in the Trematoda, the secretion of which in the perfect animal is ex-

lied from the body, but in the “ nursing generation,’ on the contrary,
pela within it, as being an organ which | probably subserves the function
of generation, and favours that of * nursing” in the first generation.

AND THEIR REAL NATURE. 115

assume with some degree of certainty, that the “ nursing”
individuals are never themselves gemmiparous, but that
they are born with germs in the organs in which the
embryos are afterwards nourished, and from all this it
appears as if the female generative organism were always
divided in those cases in which development by means
of “ nurses’ occurs, so that as in the more perfect females
an ovary especially, is formed, so in the “ zursing” indi-
viduals a much developed wferus is presented, in conse-
quence of which, they as individualized wferz, have
assigned to them as the object of their existence the
performance of the functions of a xzerus, and their com-
plete formation must thus necessarily precede that of the
germs which are committed to their fostermg care. We
cannot readily perceive the reason, that because all nurs-
ing (ammende) individuals must be of the female sex, it
should follow, that all those individuals which feed the
young (drutpflegende) should also be of that sex, and yet
this seems to be the law. Anatomy shows us that the
““ feeders’ among bees, wasps, &e., and probably those of
all insects living in regular societies are females, whose
sexual organs remain in an undeveloped state. They
present scarcely the vestige of an ovary; the uterus 1s
rudimentary, and all propagation consequently in the
material way (materiellen Seite), so to say, 1s rendered
impossible ;. the imperfection of the organ does not even
allow of their acting as “nurses” (ammen,) and the
propagative instinct, in a physical, corporeal sense passes
into a will for the propagation of the species, into a nisus
impelling to the feeding or nourishing of the young, and
the fulfilment of these impulsive duties is favoured by the
peculiar transformation which some of the organs undergo
at the expense of those intended for propagation, in order
that they may become adapted to the brmging up of the
young.”

* The jaws of the working ants are stronger than those of the male and
female; and the bees also which collect honey and wax are provided with

wide mandibles, which together form a pair of forceps. The ovipositor is in
them converted into a spiculum (defensive organ), &e.
8

114 THE ALTERNATING GENERATIONS

Whence it follows that the development of the species in
this case does not take place by means of several genera-
tions, but through several broods of the same generation.
The reason of the great number of “ feeders,” and for
the common good of “ workers,” so that they often con-
stitute thousands, whilst the fertile individuals scarcely
amount to hundreds* may be readily understood, when we
consider more closely the regular societies of Bees and Ants,
and witness the labour required for the nourishment of the
young. But on the other hand, how the development
of the species is promoted by the multitude of “nursing”
animals (amme) of which we often see thousands for each
single fertile one, appears to us difficult of explanation,
since, even all of them can only be regarded as animated
organs, which do not appear to act for or with each other.
It does not, however, seem to me improbable, that even
the Aphides, trematode nurses, and other parasites, which
are so immediately injurious to the organisms in or upon
which they live, are not destined merely to promote the
extension of the species, but that they also duce in the
organisms themselves, conditions necessarily more and
more favorable to a later generation; plants also and
animals afford us many instances, that to a certain abun-
dance of parasites there usually succeeds a complete over-
flow of them.

I conclude with the remark, that, masmuch as in the
system of “ nursing,” the whole advancement of the
welfare of the young is effected only by a still and
peaceful organic activity, is only a function of the vegeta-
tive life of the individual, so also all those forms of
animals in whose development the “nursing” system
obtains, actually remind us of the propagation and vital
cycle of plants. For it is peculiar to plants and as it
were their special characteristic, that the germ, the pri-
mordial individual in the vegetation or seed, is competent
to produce individuals which are again capable of pro-

* In a hive of bees there are from 2000 to 3000 males, and only one
female to 50,000 “ feeders” and “ workers.”

AND THEIR REAL NATURE. 115

ducing seeds or individuals of the primary form or that to
which the plant owed its origin, only by the intervention
of a whole series of generations. It is certainly the great
triumph of Morphology, that it is able to show how the
plant or tree (that colony of individuals arranged in
accordance with a simple vegetative principle, or funda-
mental law,) unfolds itself through a frequently long
succession of generations, into individuals, becoming con-
stantly more and more perfect, until, after the imme-
diately precedent generation, it appears as Calyx and
Corolla with perfect male and female individuals ;
stamens (Staubblättern,) and pistils (Fruchtblättern) —
(so that even in the vegetable kingdom the grosser her-
maphroditism does not obtain, which is still supposed to
take place in the animal,) and after, the fructification
brings forth seed, which again goes through the same
course. Itis this great and significant resemblance to
the vegetable kingsdom, which in my opinion is presented
by the entozoa, and all “ nurse” generations (amme,) and
to which I have alluded in the preceding Essay ; I might
almost say, that the condition of continued dependance
incidental to the animal life, is, to a certain extent, one
of less perfection than that which is presented in the
progressive elevation in development effected by the
agency of the vegetative life.

EXPLANATION OF THE FIGURES.

PLATE I.

Fies.1-40. THE DEVELOPMENT of Medusa Aurita.

N.B. Almost all the figures are taken from the
memoir by Sars, in Erichson’s Arch, 1 B. 1 H.
tab. i—iv, some from a work by the same author,
entitled ‘ Beskrivelser og Jagttagelser over nogle
merkelige eller nye 1 Havet ved den Bergenske Kyst
levende Dyr, o. s.v., (Bergen, 1835.) Figs. 1—19
represent especially the progeny of Cyanea capillata,
but according to Sars it corresponds so perfectly
with that of Medusa aurita, that in most cases it is
impossible to distinguish the one from the other.
Fig. 35-40 only are from my original drawings,
made in my Icelandic journey.

Fies. 1-19. Show the development of the first genera-
tion, which I have named Medusa-nurses.

Fies. 1-4. The ciliated, free-swimming, infusorial
progeny of the Meduse, newly escaped from the
peculiar receptacles in the tentacles of the female
Medusa, in which they undergo a sort of incubation

Fie.

EXPLANATION OF

for a time. Figs. 1, 2, 3 are viewed from the wider
end, and fig. 4 from the narrower. At the wider
end is seen a depression, by which they afterwards
affix themselves by suction.

5. An individual which has already affixed itself at
the surface of the water.

Fies. 6-9. Show the way in which the young Meduse

Fig.

after (on the third day) having become attached by
the wider end to some fixed object, gradually grow
and change their form, until the hitherto slender,
projecting extremity becomes thicker, and the body
passes through the cylindrical (figs. 7, 8). into the
clavate form (fig. 9.)

10. A club-shaped individual, seen from above, in
which now an actual opening (but no oral orifice)
has been formed; this orifice is surrounded by a
circular elevated margin, and presents four indis-
tinct tubercles.

Fies. 11-14 represent a similar individual in its ad-

vancing growth; the four inferior tubercles are
gradually more and more elevated (on the fourth
and fifth day) (figs. 11, 12, 13) finally become
filamentous and assume the form of tentacula

(fig. 14.)

Fies. 15, 16. Individuals at the age of from ten to

Fie.

eleven days; the number of tentacles is increased
to eight, four new ones having sprung up between
the older ones; fig. 15 is seen from the side, fig. 16
from above.

17. An individual which besides the eight older ten-
tacles, exhibits five new ones springing up: viewed
from above (on the twelfth day.)

en

THE FIGURES. 119

Fies. 18, 19. Individuals much older, and possessing -
the full number of tentacles; smaller individuals
are seen upon them, as if arising from gemmee or
runners (stolones.)

’

Fies. 20-34 represent the development of the second gene-
ration (THE MEDUSA LARV) within the first (THE
MEDUSA “ NURSES’), and their completion into
perfect MEDUSA.

Fies. 20-22. Show the commencing development of
new animalcules in the posterior part of the body
of the polypiform “ zurses”’; the development causes
the appearance of a transverse division of the
animal. Fig. 20 is an individual with one trans-
verse ruga. Fig. 21 with more, when several germs
have become developed. Fig. 22 with many; the
borders of the new animalcules are now free, eight-
lobed; they possess the power of spontaneous
motion. The whole set (Strodi/a) is, however, com-
plete, and the “nurse” animal is placed upon the
pile of Zarve, as it may be termed.

Fies. 23, 24. Show how the Medusa-larve detach
themselves from the “ »urse” animal. Fig. 24 is a
bunch or set of larve, the “ xurse’” belonging to
which has already become detached: (of a natural
size.) Fig. 23 is the lowermost part of such a set,
and shows how the /arve rise up from one another,
and are finally altogether separated.

Fies. 25-30. The free Medusa-larve proceeding to their
further development. Fig. 25, a /arva of the natural

size and recently separated. Fig. 26, an individual
rather more developed, and Fig. 27, the same seen
from below. Fig. 28, a still larger individual (of

120

EXPLANATION OF

the size of nature). Fig. 29, one of much larger
size seen from above. Fig. 30, one fully developed,
but not yet full-grown, with four perfect, cloven,
oral tentacles, and numerous outstretched marginal
tentacles.

Fies. 31-34. Exhibit m magnified figures, the changes

which the edge of the bell-shaped body of the
medusa larva undergoes, and show the gradual
rising and growth of the marginal tentacula (figs.
31-32-33) in the three stages of development shown
in figs. 26-28-29, together with the division of the
ventricular tube into four arms (fig. 34.) —

Fires. 35-40. May serve to prove, that the polypiform

Fig.

“NURSE animal is a stationary MEDUSA; all the
figures are much magnified.

35. A polypiform “nurse” (Scyphistoma) viewed
laterally. Fig. 36, a smaller individual, much de-
pressed towards its stem; within the border of
tentacles, is seen the mouth of the bell, and within
this again the oral orifice. Fig. 37, a similar indi-
vidual, which has protruded the ventricular tube,
through the mouth of the bell and the circle, formed
by the reclined tentacles. Fig. 38, an individual
viewed from above, in which the tentacles are ex-
tended almost horizontally ; the marginal membrane
around the mouth of the bell is also dilated, and
retracted towards the base of the tentacles ; four
large vessels, appearing like thick-rounded ridges or
elevations, descend from the margin to the stomach
which is situated at the bottom of the bell. Fig. 39.
‘The outline of an individual whose marginal mem-
brane is almost wholly retracted around the mouth
of the bell; in this figure are also seen the annular
vessel around the contracted mouth of the bell, the
annular vessel at the base of the tentacles, and the

THE FIGURES. 121

four radiating vessels which connect the two former.
Fig. 40, represents the whole vascular system in
connexion, as far as I have been able to trace it.

Fies. 41-47. Tur DEVELOPMENT OF THE CLUB-SHAPED

Fie.

Fig.

Fie.

PoLYPr, CORYNE FRITILLARIA.

N.B. (The figures are after my own drawings,
from specimens observed in Iceland. Fig. 47 istaken
from Sars, (/. c.,) for the purpose of comparison.)

41. A club-shaped polype, Coryne fritillaria, of
the natural size; it consists of a so-called club-
shaped head, which is the original animal, or the
first generation ; astem which supports this head,
and 3-4 quadrangular bell-shaped bodies (indivi-
duals of the second generation) which hang on short
peduncles around the base of the club-shaped indi-
vidual.

42. One of the bell-shaped individuals (but very
little magnified) which has become detached from
the “nurse.” Fig. 44, a medusa-like, bell-shaped
individual, met with swimming free in the sea; it
has more than doubled its size since its separation,
and particular organs (generative?) have become
developed; of natural size. Fig. 43, the same very
little magnified. Fig. 45, the same very much
magnified, to allow of a better msight into its struc-
ture. Fig. 46, some cells on the edges of the bell-
shaped individuals, highly magnified, in order to
show the vesicles, situated half in and half out of
them.

47. A young bell-shaped individual of the Cory-

morpha nutans, Sars, for comparison.

122 EXPLANATION OF

Fies. 48-57. Tar DEVELOPMENT OF THE CAMPANULATE
PoLYPE,—ÜUAMPANULARIA GENICULATA.

N.B. All the figures (except fig. 48) are taken
from the celebrated memoir of Lovén on this sub-
ject. (Wiegmann’s Archiv für Naturgeschichte, 1837.
Tab. VI.)

Fic. 48. A specimen of Campanularia geniculata slightly
magnified. It constitutes a whole colony of indi-
viduals, of somewhat different aspects, and consisting
of several generations; first appear individuals of
the form aaa; they occupy the summits of the
branches, and elicit afterwards the larger individuals
of the form 6.6 6, which are always situated in the
axille of the branches. Within, the second form
(the “ zurses’’) is hatched the third and more perfect
form ce ec, which is smaller and globular, and which
in a short time is to be seen placed upon the indi-
viduals 6 6 6, whilst the young proceeding from their
ova, make their escape.

Fies. 49-57. Highly magnified, show the relations between
the various forms (generations) of the individuals.

Fie. 49. A magnified full-grown individual of the first
generation—a “ parent-nurse” (grossamme) as I term
it— with a branch growing out of it.

Fies. 50, 51. Represent two periods of the successive de-
velopment of a polype of the same generation, at
the extremity of the branch, or of the stem.

Fie. 52. A highly magnified individual of the second
generation (“ nurses,’ amen); on one side of the

Fig.

THE FIGURES. 123

intestinal tube is seen the commencing development
of the third generation (the perfect females.)

53. Two perfect females, which are protruded through
the operculum of the “ zurse ;” in one of them is
seen the fully-developed egg, which may also be
distinguished even before the female quits the “ zurs-
ing animal’ (vide fig. 52); in the other, the young
are on the point of escaping into the water.

Fies. 54-57. Show the metamorphosis of the young, and

Fig.
Fie.

Fig.

Fic.

the way in which a new polype stem is founded, toge-
ther with the origin of the ‘‘PARENT-NURSES.”

54. The oval ciliated, young polype (in the water).

55. The young polype, after it has affixed itself
and become contracted into the form of a disc.

56. The same, rather older; the disc is beginning
to divide into several portions, and presents in the
centre a small tubercle.

57. The same, after this rounded tubercle has in-
creased in height, and has formed the lower part of
the stem of the compound polype.

EXPLANATION OF

PLATE II.

Fies. 1-8. Tar DEVELOPMENT OF THE FLUKE, Distoma

PACIFICA.
N.B. All the figures, except figure 1, which is

taken from Siebold’s Memoir on Monostomum muta-
bile, m Wiegmann’s Archiv. f. Naturg., 1836, are
from my own drawings.

Fies. 1-2, Show the first generation in the development of

Fig.

Fig.

the distoma,—the ““ PARENT-NURSES.”
2

1. First stage in the development of Monostomum
mutabile ; 1 a, an ovum, through the shell of which
is seen the developed embryo, which is represented
in 15, after it has quitted the egg, and is swimming
about at liberty; Ic, and 1d, are the same indi-
vidual, after its metamorphosis from an active form
into an inactive sluggish creature, which is not itself
a mother, but nourishes within it a progeny from
which, in the third generation, a parent animal does
proceed. I call this a “ parent-nurse” (grossamme).

2. Animals which mhabit fresh-water snails, as
entozoa, and after a few generations become true
Distomata, or resemble them; on which account, ın
the text I have termed them their “ purent-nurses.”
From the analogy m the external form, with the
creatures which proceed from the ova of Monostomum,
and are afterwards metamorphosed, it must be as-

THE FIGURES. 125

sumed that those creatures which are produced from
the ova of the Distoma in the common embryonic
form of the Distomata (compare fig. 1 6)—the first
generation—are of an allied nature. Figs. 2 d and
2¢ are individuals, in which is a new progeny in
the form of globular germs, and which occupies
only the posterior part of the body; 25 and 2a
show partly developed embryos, filling nearly the
whole cavity of the body.

Fies. 3-4. Zhe second generation in the development of

Fic.

Fic.

the Distoma. (The ‘‘ nurses,’ amme.)

3. A series of forms, through which the young
pass from the globular germs in the “ parent-
nurses,’ figs. 3a—d; during their growth they be-
come at first oval, figs. 3 e—g ; but afterwards more
elongated, and almost cylindrical (47 47,) whilst a
small process which is situated at one end is length-
ened into a sort of tail, and a depression at the op-
posite extremity is formed into a mouth and oral
cavity. Figs. 3m nop, are older embryos, which
exhibit the parts named above more distinctly; a
pair of lateral processes at the root of the tail, as
also a depression below the head, become more
evident; the interior large cavity represented at v is
a digestive sac. Figs. 30 and p are fully developed
individuals (“ zwrses’’) in which the germs of another
generation (the third) are distinguishable just above
the root of the tail.

4. The growth of the second generation, the
“ nurses’ (amme) and the hatching or incubation of
the third generation (the Distoma-larve). 4 d is
very young, and has recently quitted its “‘ zurse”
—the “ parent-nurse” (grossamme) ; 4 c is half-grown,
and the germs of the third generation contained in
it are partly developed into embryos, and show that

126

EXPLANATION OF

they will attam a form different from that of the
animal in which they are situated (or fostered). 4 6
contains fully-developed embryos, which exhibit the
long tail and an internal, bifurcated digestive organ ;
they fill the whole cavity of the body of the “ nursing
animal’ so that the saccular digestive organ of the
latter is reduced into a small organ marked v. 4 a
completed “ xwrses” shghtly magnified.

Fires. 5, 6,7, 8. The third generation of the Distoma ;

Fic.

. Fie.

Fig.

the embryo, larva, pupe, and perfect Distoma.

5. The forms gradually assumed by the young
within the “zursing” animals, whilst from germs
they are formed into embryos; Cercarie, Distoma
larve; figs. 5 a—e spherical germs, which are
elongated (g— 4) and exhibit a trace of life (2) whilst
a tail begms to be distinct from the body. In
figs. k and / the form of the Cercarie is completed,
and several of the internal organs are distinguish-
able. Fig. m unborn Cercaria viewed from the
side.

6. A Cercaria which has quitted its “ zurse” and
swims free in the water. The outward form of the
body corresponds with that of the Distoma, as also
do the internal organs, but is wanting the tail
(vide fig. 8). The head and the collar situated be-
neath it correspond with the same parts in the two
preceding generations of “nurses” and “ parent-
nurses’ (vide fig. 2 and fig. 4). 'The lateral pro-
cesses in these are the lateral portions of the poste-
rior part of the body surrounding the root of the
tail; the tail is one and the same organ in all the
three generations.

1. Distoma pupe or Cercarie in the state of pups
or when they have cast off the tail and are sur-

Fig.

THE FIGURES. 127

rounded in a mucoid case. 7d, a portion of the
skin of a fresh-water snail, upon which a number of
Cercarie have become pupe; slightly magnified.
7a and 75 single pupe highly magnified, and de
under the same magnifying power as that under
which the Cercaria, fig. 6, is figured. A circlet of
spines, which was concealed in the collar of the
Cercaria, 1s at this period very distinct, and pre-
sents itself m various positions, according to the
motions of the animal within the pupa case.

8. The animals proceeding from the pupe ; true
Distomata ; fig. 8 a, an individual extracted from
the pupa case, and in a rolled up position; 8 4, Sc,
8 d, individuals which have spontaneously quitted
the pupa cases, and have penetrated a short distance
into the body of the snail. 85 still retains the
circlet of spies on the collar around the oral orifice.
Sc has just lost the spmes, the marks of which are
still evident on the collar, which is diminishing in
size. 8d an individual more deeply buried than
the preceding ones in the body of the snail; the
collar still smaller. 8 e and 8 / individuals occurring
in the outermost convolutions of the liver.

128

EXPLANATION OF

PLATE IM.

Fres. 1-6. Tar DEVELOPMENT OF THE DISTOMA TARDA.

Fic.

N.B. All the figures are from original drawings,
and under the same magnifymg power, except
figs. 19, Aa, and 65, which are but little mag-
nified.

1. The development of a series of sacciform crea-
tures which occur on the viscera of the snail, and
appear to be the “nurses” of young, which after-
wards assume the Distoma-form : Distoma-“NURSES.””
From extremely minute, oval or pyriform bodies,
1 a, and | 4, they are formed into longer or shorter,
more or less regular bodies possessing a vermicular
motion, 1c, 1d, 1d’, and inclosing a cavity in
which a multitude of germs are placed which are
commencing their development. 1 e, an individual
possessing rather more powerful vermicular motion,
and presenting half-developed embryos; the resem-
blance which these embryos bear to the Distoma-
larve is already apparent. 1,/, an individual which
has lost all its power of motion, and whose skin has
become distended almost mto a delicate membrane
by the vast crowd of embryos (viz. developed Cer-
cari@). 1.9, an assemblage of these Distoma nurses
as they usually appear when covering the internal
organs of the snail.

THE FIGURES. 129

Fies. 2-6. The last (third ?) generation of the Distoma.

Fic.

Fic.

Fic.

Fie.

Embryos, Larve, Pupe, Distomata.

2. The successive forms of the development of the
germs into embryos; the Distoma-larve correspond
wholly with the forms given in Plate II, figs. 5.
The spiculum on the anterior part of the head is at
last distinguishable.

3. Distoma-larve or Cercarie. (Cercaria armata,
Siebold,) after they have quitted the “wrses” and
snails and are swimming about in the water; 3 4
and 3 d, individuals with contracted bodies, moving
on a flat surface ; 3 e, a lateral view.

4. Distoma-pupe. 4a, a portion of the integu-
ment of the snail, closely beset with the oval Dis-
toma larve, in the pupa state; slightly magnified.
46, a Distoma larva, on the point of forming its
mucoid case. 4c, a larva recently become a pupa,
the abdomen of which is turned upwards; (¢o"”
long, #5 broad). 4d and 4 e, rather older pupe ;
Af and 4 9, pupa, the animals of which are ready to
quit the pupa case. The organs marked s—é are
the same in all the figures as in fig. 5; s, the ori-
fice of the excretory organ; 7, the borders of the pos-
terior body surrounding the root of the tail, which
form a horse-shoe shaped acetabulum; x, the abdo-
minal sucker ; v, a pore situated between the sucker
and the posterior border of the dody, which in
figs. 4 f and 4g appears to be connected with the
serpentine organs vz ; y, the excretory organ ; @, the
oral orifice ; ö, the cast off frontal spiculum.

5. The animals produced from the pup&, irue

Distomata, Distoma tarda; 5 a, an individual re-

cently escaped from the pupa; 55, 5c, 5d, indi-

viduals extracted from the pupe, for comparison
9

130

Fig.

EXPLANATION OF THE FIGURES.

with fig. 5a; figs. 5e, 5/, and 54, are full-grown
individuals, found in the liver of the fresh-water
snail.

6. Large “nursing” individuals, in which the Des-
toma-larve are already become pupe, and have at-
tained their full development. Fig 6 a, a “ nurse”
in which a fully developed Distoma tarda may be
seen among a crowd of fully and half developed
larve. Fig. 6 6, a similar “ nurse” with four such
Distomata, which are placed alternately on the op-
posite sides.

Fies. A, B, C, The EcHINORHYNcHUS of the sole, in a

Fig.

young state.

A. An echinorhynchus, inclosed in a thick, mem-
branous cyst. Fig. 2, the same extracted from the
cyst. Fig. C, the same with its proboscis protruded.

INDEX.

‘ Alternations of generation, definition
of term,l; distinction between it
and ‘ Metamorphosis,’ 6

Amphistomum clavatum, 99

Anadonta, animaleule in, and on, 90

Ancylus lacustris, 95

Ants, feeders among, 109

Aphides, mode of generation of, 108

Aseidie, Milne Edwards on, 47; de-
scription of young, 48; circulation
of blood in, 47

Aspidogaster conchicola, 93

Astacus fluviatilis, occurrence of Disto-
mata in muscles of, 95

Baer on Distoma duplicatum, 92

Batrachians Trematoda enter
without, 99

Bees, “ feeders” among, 109

Bojanus, yellow cylindrical worms of,
62

from

Bothriocephalus, nature of, 103

Botryllus, 48, 50, 51

Bucephalus polymorphus of Baer, proba-
bly only a nursing animal, 96

Campanularie, Loven on, 32

Campanularia geniculata, description.
and development of, 32; “ zurses”
of, 36

Cercarie, description of pupa state of,
57; developed from “ King’s yellow
worms’ of Bojanus, 62; description
of development, 64; mode of exit
from “nurses,” 65; frequency in
auricle of snail, 66; origin of zurses
of, 69; “ Nests,’ 68; “ Parent
nurses’ of, 69

Cercaria echinata, description of, 53;
armata, description and develop-
ment of, 74; pupa state of, 77;
Distoma which originates in, 80;
ephemera, “nurses” of, described
only by Siebold, 87-88; Mitzsch’s
observations on pupa state of, 88 ;
Distomata developed from, ib.

Cestoid entozoa, Miescher’s memoir
on, 102

Cestoid worms, resemblance to vege-
tables, 104

Chamisso, 1819, on the alternate ge-
neration of Salpe, 40

“ Chaotic swarm” of Baer, 90

Claviform Polypes, 26

Colpodium, 99

Coralline Polypes, 37

Corymorpha mutans, 27, 30

Coryne, 26; Ehrenberg on, 27; fritil-
laria, description and development
of, 27; aculeata, 30; vulgaris, 31

Cyanea capillata, 25

Cystic entozoa, a nursing generation,
100

Diplostomum clavatum, 98 ; volvens, ib.

ne 59
istoma hepaticum, 52 , duplicatum, 87;
larva of Aspidogaster conchicola, cer-
tainly a larval form, 93; “ Parent
nurse’ of, ib.; “* Nurses’ of, ıb.;
eirrigerum, 95; annuligerum, 99

Distomata developed from Cer. ephem.,
88

Echinorynchi, “ loose ovaries” of, their
probable nature, 101; mode in
which they penetrate into the ani-
mals infested by them, ib.

Ehrenberg on Coryne, 27

Ephyra, 19—20

Eschricht, examination of his theory
of the development of Sauipe, 40, 42;
Observations on the Zehinorynchi
of Haddock, 101; on Bothriocepha-
lus, 103; anatomical researches on
the Salpe, 112

Germ-sacs of Siebold, the “ nurses”
of, Cer. ephem., 89.

Holostomum cuticola, 98; brevicauda-
tum, 1b.
Hydatid cysts, containing Distomata, 98.

132

King’s yellow worms, the nurses of
Cercarie, 62.

Leucochloridium paradoxum, 95.

Limneus stagnalis, 53-59, 60.

Loven on Syncoryne ramosa, 30; on
Campanularıe, 32.

Lucernarie, Ehrenberg on the, 19.

Meduse, general description of, 11;
propagation of, 12; “ nurses’ of,
24-26; M.aurita, development of, 13;
description of young of, 14; Strobila
developed into, 19; history of re-
searches on, ib.; relation of periods
of development to season, 25; M.
papillata, Abilgaard on, 31.

Meyen on Salpe, 40.

Miescher, memoir on cestoid entozoa,
102.

Milne Edwards on Ascidia, 47.

Monostomum, 61; M. mutabile, deserip-
tion of young of, 71.

Müller, ©. F., on Coryne, 30.

Nematoidee, 100.

Nitzch on the pupa state of Cercarie,
ie

Nordman on Zrematoda in the eyes of
animals, 96.

““ Nurses” of Meduse, 24-26; of Salpa®
46; of Campanularie, 36; of Cer-
carie, 88.

““ Nurses” and “feeders” of insects,
distinction between, 111; both al-
ways females, ib.

Opalina ranarum of Ehrenberg, 96.

Paludina vivipara, 62; occurrence of
pupz in auricle of, 88.

Parameciun, 90.

“© Parent-nurses” of Cercarie, 69; of
Distoma duplicatum, 93.

Planorbis cornea, 53.

INDEX.

Plumularie, 31.

Polypes, claviform, 26; coralline, 37.

Pupa state of Cercar. ephemera, 88 ; of
Cercar. armata, 77.

Psorospermata of Müller, 97.

Pyrosoma, 47.

Sacculi in which Cercari@ occur, 81;
are in fact the “nurses,” 84.

Salpe, alternate generation of, 38-39 ;
description of, 38; associated and
solitary, 39; Meyen on, 40; Cha-
misso on the alternate generation
of, 40; examination of Eschricht’s
theory of the development of, 40-42;
Eschricht’s anatomical researches
on, 112; S. zonaria, 39-40; S. pin-
nata, Chamisso on, 41; S. cordi-
Jormis, 40-41. .

Sars, M., on Corymorpha nutans, 30;
on Scyphistoma-strobila, 21; deserip-
tion of the young of Ascidie, 48;
on the development of Salpe, 46.

Scyphistoma-strobila, description of, 19,
20, 21.

Siebold on pupa state of Cercar. 58;
period of year at which the animals
quit the pupe, 59; on develop-
ment of Distomata within saccular
“ nurses,” 85.

Spherularia, probably a “ nurse,” 100.

Succinea amphibia, occurrence of, Leuco:
paradox in tactile, horns of, 95.

Syncoryne Sarsü, 27, 31; S. ramosa,
Loven on, 30-31.

Termites, division of labour among,
110.

Tetrarynchus, 102.

Trematoda, development of, 52.

Trematode animals, development of,

Tubularie, aie

Wasps, feeders among, 109.

PRINTED BY C. AND J. ADLARD,
BARTHOLOMEW CLOSE. _

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REPORT

SECOND ANNUAL MEETING

OF

mii RAY SOCLETY,

Hextp Ar CAMBRIDGE, June 23, 1845.

PROFESSOR JOHN PHILLIPS, F.R.S.

IN THE CHAIR.

WITH

THE LAWS OF THE SOCIETY, LIST OF OFFICERS, MEMBERS,

&c. &c.

LONDON:

©. AND J. ADLARD, BARTHOLOMEW CLOSE«

OFFICERS OF THE RAY SOCIETY.

Bresident.

Proressor Bent, F.R.S.

Council.

Proressor D. T. Anstep, M.A. F.R.S.

Cuas. C. Bapineron, Esq. M.A. F.L.S.

Proressor Batrour, M.D. F.L.S.

Rogrrt Batt, Esq. M.R.I.A. Sec. R.Z.S.F.

Rev. M. J. BERKELEY, M.A.F.L.S. -

Georce Busx, Esq. F.R.C.S.

J. DALryMmPue, Esq. F.R.C.S.

C. Daugeny, M.D. F.R.S.

Sir P. G. Ecerton, Bart., M.P. F.R.S.

PROFESSOR EDWARD Forses, F.R.S. L.S.

RopErT K. GreEVvILLE, LL.D. F.R.S.E. H.M.C.P.S.
Sir W. Jarpine, Bart. F.R.S.E. L.S.

Rev. LEONARD Jenywns, M.A. F.L.S.

PROFESSOR Owen, F.R.S.

Proressor JOHN PHıLLıps, F.R.S.

Proressor F. Royue, M.D. F.R.S. L.S.

PRIDEAUX J. SELBY, Esq.

Hueu E. STRICKLAND, Esq. M.A. F.G.S.

Wm. Tuompson, Esq., Pres. Nat. Hist. Soc. Belfast.
N. B. Warp, Esq. F.L.S.

. Treasurer.
J.S. BOWERBANK, Esq. F.R.S. F.L.S., 45, Park Street, Islington, London.

Secretaries.

G. Jounston, M.D., Berwick upon Tweed.
E. Langester, M.D. F.R.S. F.L.S., 22, Old Burlington Street, London.

REPORT OF THE RAY SOCIETY.

In presenting a Report for the present year, your Council feel it
incumbent on them to explain the cause of the delay which has taken
place in the publication of the volumes due for the first year’s sub-
scription. When they presented their Report last year there was
every prospect of a speedy issue of the first volume, but on account
of the increase of members rendering it necessary to reprint a large
portion of the work after it had gone to press, and the nature of the
Reports on various branches of Natural History requiring that the
proof sheets should pass through many hands for correction, the issue
has been unavoidably delayed, and they feel that, but for the exertions
of many members of the Society, to whom the sheets were sent for
correction, it would have been impossible to have presented that
volume at the present time.

The Council feel great pleasure in accompanying the presentation
of the volume above alluded to with the first part of the great work
on the British Nudibranchiate Mollusca. The very great value and
importance of this work, recognized as they have been by all British
Zoologists since its announcement, have justified the Council in
sparing neither pains nor expense in producing it in a form not un-
worthy of its intrinsic merits. They feel assured that the new pro-
cess of lithotinting which has been employed on this occasion, and
which affords almost facsimile imitations of the original drawings,
will satisfactorily show to what extent that process may be employed
in the illustration of subjects in Natural History. The superinten-
dence of the publication of this work has been committed to a sub-
committee, consisting of Dr. Jounston, Professor Epwarp ForBes,
and Mr. Wo. Thompson.

It was fully expected that a volume, consisting of ‘ Memorials of
Ray,’ would have been ready for distribution, with the works now
before the Society ; and notwithstanding some unexpected delay, the
Council have to announce that this work, edited by Dr. LAnkESTER>
will be presented very shortly to the Members as part of the first
year’s publications.

The Council have the satisfaction of stating that the following
works are either completed or ina forward state for publication, viz.:

4,

1. Burmeister, On the Organization of Trilobites; edited by
Professors BELL and E. Forses.
. ZUCCARINI, On the Morphology of the Conifera.
. Ganp, On the Geographical Distribution of the same.
. GrisesacH’s Report on Botanical Geography.
. STEENSTRUP, On the Alternations of Generation, translated
by GEoRGE Busk, Esq.
6. Part II, of the British Nudibranchiate Mollusca of ALDER and
Hancock.

The Council have also to announce that arrangements are now
pending with Professor Acassız, of Neufchatel, for the publication
of his great work of a complete Bibliography of Zoology and
Paleontology.

The following works are either preparing for publication or under
consideration :

1. Tconographia Linn&ana, to consist of illustrations of the
specimens in the Linnean collection, at present existing in the
Museum of the Linnzan Society ; to be edited by Professors
Beut and E. Forses.

2. Continuation of Reports on the Progress of Zoology and
Botany.

3. Translation of AzAra’s Natural History of Paraguay.

It is satisfactory to the Council to be able to state that the list of
Members is at present nearly 700, and that daily accessions are being
made to the number.

The Council cannot conclude this Report without recording their
great obligations to the Council of the Geological Society of London,
for granting them the use of their room for the purpose of conducting
their business.

Ors Co to

Dr. Abstract of Treasurer's Account, 1845. Cr.
Ease ida 7 £28. ds
To balance in hand at By Printing and Engraving . 194 11 8
the last audit . . 189 4 2 | By Advertisements . . 915 O
To Subscriptions re- By Translations . 3 5 PR 6
ceived to June 8th, By Salary to Clerk, l qr. . 6 5 O
1845. . . . . 3814 18 9/ By petty expenses, books, sta-
tionery, &c. 5 : g lly a)
£250 3 ]
To Balance in Treasurer’s
hands 0 5 5 . 253 19 10
£504 211| £504 211

The above accounts, extending from Sept. 28th, 1844, to June 15th, 1845,
have been examined by us, and compared with the vouchers, and found
to be correct, Signed, W. SPENCE,

Frep. S. Farre.

5

Moved by W. Spence, Esq.; seconded by W. YARRELL, Esq.
That the Report now read be adopted and printed for circulation
among the Members.
Moved by Professor CLARKE ; seconded by Horron Luoyp, Esq.

That the thanks of this Meeting be given to the Members of the
Council for the past year, and that the following gentlemen be
requested to act as Council for the ensuing year.

D. T. ANSTED, ESQ. R. K. GREVILLE, ESQ.
CHARLES C. BABINGTON, ESQ. SIR W. JARDINE, BART.
J. H. BALFOUR, M.D. REV. L. JENYNS.

ROBERT BALL, ESQ. RICHARD OWEN, ESQ.
THOMAS BELL, ESQ. JOHN PHILLIPS, ESQ.
REV. M. J. BERKELEY. F. ROYLE, MD.

GEORGE BUSK, ESQ. PRIDEAUX J. SELBY, ESQ.
J. DALRYMPLE, ESQ. HUGH E. STRICKLAND, ESQ.
C. DAUBENY, M.D. W. THOMPSON, ESQ.

SIR P. G. EGERTON, BART. N. B. WARD, ESQ.
EDWARD FORBES, ESQ.

Moved by Sir Henry De LA Becue; seconded by Dr. Fauconer,

That the thanks of this Meeting be given to Professor Betz,
President, to Mr. BoweErBAnk, Treasurer, and to Dr.
Jounston and Dr. LANKESTER, Secretaries, and to the Local
Secretaries, for their services.

Moved by Professor Atuman ; seconded by S. HAILSToNE, Esq.

That the thanks of this Meeting be given to H. E.STRICKLAND,
Esq. to W. Macponaup, Esq., and to Dr. Lanxesrer, for
their assistance in translating the volume of Reports on the
Progress of Zoology and Botany, and to Dr. Jonnston, Pro-
fessor E. Forses, and W. Tuomrson, Esq. for their aid in
bringing out the work of Messrs. ALpER and Hancock, on the
Nudibranchiate Mollusca.

HONORARY LOCAL SECRETARIES.

Aberdeen
Bath
Beccles
Beverley
Birmingham
Bristol
Bury St. Edmunds
Chelmsford
Cheltenham
Cork
Derby se
Edinburgh
Gloucester
Godalming
Halifax
Hatfield
Hereford
Hertford
Hull
Lancaster
Leeds
Leicester
Liverpool

Lydd, Romney Marsh .

Lynn ide
Manchester
Newcastle-on-Tyne
Norwich . I
Nottingham
Plymouth

Reading ..
Reigate ..

Ryde, Isle of Wight
Scarborough
Shrewsbury
Sidmouth
Stowmarket

Tenby, South Wales
Torquay

Whitehaven, Cumberland

Winchester
Witham
Worcester
York

Dr. Dickie.

R. F. George, Esq.
H. Davey, Esq.

Dr. Beverley Morris.
Dr. Percy.
Dr. W. Budd.
Dr. Ranking.

G. Meggy, Esq.

W. CE

Dr. Harvey.
R. J. Bell, Esq.

Dr. Douglas Maclagan.
J.M. Hitch, Esq.
J.D. Salmon, Esq.
Dr. Inglis.

Lloyd Thomas, Esq.
T. Tucker Price, Esq.
De Reed.

G. Norman, Esq.

S. Simpson, Esq.

T. P. Teale, Esq.

J. Harley, Esq.

Dr. Dickenson.

Dr. Plomley.

Geo. Sayle, Esq.
Peter Barrow, Esq.
J. Thornhill, Esq.
Ay Brightwell, Esq.
Booth Eddison, Esq.
Rev. J. Hore.
S. Lovejoy, Esq.

W. Hansom, Esq.
Dr. Bell Salter.
Dr. Murray.
Rev. W. A. Leighton.
Dr. Cullen.
R. C. Bree, Esq.
Dr. Falconer.

Dr. Battersbey.
Wm, Dickinson, Esq.
Dr. A. D. White.
Jacob H. Pattisson, Esq.
Dr. Streeten.

W. H. Tuke, Esq.

THE FOLLOWING MEMBERS OF THE COUNCIL.

Belfast
Cambridge
Dublin
Glasgow
Greenwich
King’s Cliffe
Oxford

W. Thompson, Esq.
Charles C. Babington, Esq.
Robert Ball, Esq.
Dr. J. H. Balfour.
George Busk, Esq.
Rev. M. J. Berkeley.
Dr. Daubeny.

SS:

THE LAWS OF THE RAY SOCIETY.

I. That this Society shall be called Tue Ray Socıery ; and that its object
shall be the promotion of Natural History, by the printing, of original works
in Zoology and Botany; of new editions of works of established merit; of
rare Tracts and MSS.; and of translations and reprints of Foreign works which
are generally inaccessible from the language in which they are written, or
from the manner in which they have been published.

N.B.—It will be a direction to the Council that they shall not print any-
thing that appears to them suitable to the Transactions of established
Societies ; nor any work which a respectable publisher shall undertake
to publish without charge to the author.

II. Every subscriber of One Guinea annually to be considered a Member of
the Society, and to be entitled to one copy of every book published by the
Society during the year to which his subscription relates; and no Member
shall incur any liability beyond the annual subscription.

III. That the annual subscriptions shall be paid in advance, and considered
to be due on the 2d day of February in each year; and that such Members as
do not signify their intention to withdraw from the Society before the 2d day
of June, shall be considered to continue Members, and be liable for the year’s
subscription.

IV. The management of the Society shall be vested in a Council of
Twenty-one Members, of whom one third shall have their stated residences
in London, and all of whom shall be eligible for re-election at the annual
meeting.

V. That the Council hereafter shall be elected by the Members, at a meet-
ing to be held at the time and place of the meeting of the British Association
for the Advancement of Science, and that no Member whose subscription is
in arrear be allowed to vote at any meetings.

VI. That the Council shall elect two Secretaries (one of whom shall be
resident in London) and a Treasurer, who shall ex officio be Members of the
Council.

Vil. The annual subscription shall be deposited in a chartered bank, in the
name of the Treasurer and two Members of the Council.

VIII. The accounts of the receipt and expenditure of the Society shall be
examined annually by two Auditors appointed by the Council; the Auditors
to be Members of the Society, who are not Members of Council, and their
statement circulated among the Subscribers.

IX. That the number of copies of the Society’s publications shall, unless
otherwise directed by the Council, be limited to the number of actual Sub-
seribers who shall have been enrolled, and paid their subscriptions, on or
before the 2d day of June.

X. That the Editors of Works published by the Society be entitled to a
number of copies, not exceeding 20, as may be decided by the Council.

MEMBERS ARE REQUESTED TO OBSERVE THE FOLLOWING

REGULATIONS FOR THE DELIVERY OF BOOKS.

They are delivered, free of expense, within three miles of the General
Post Office, London.

They are sent to any place in England, beyond the distance of three miles
from the General Post Office, by any conveyance a Member may point out.
In this case the parcels are booked at the expense of the Society, but the
carriage must be paid by the Member to whom they are sent.

They are delivered, free of expense, at any place in London which a Mem-
ber, resident in the country, may name.

They are sent to any of the Hon. Local Secretaries of the Society, each
Member being expected to pay the Local Secretary a due share of the carriage
of the parcel in which the books are sent. ,

Any number of country members may unite, to have their books sent in one
parcel, to any address they may name. In this case they are requested to depute
one of their number to transmit to the Secretary for London a list of the
names of those whose books are to be included in the same parcel.

Those Members who wish their books to be included in any of the parcels
to Local Secretaries, are requested to send in their names (with their Christian
name in full) and particular address to the various Local Secretaries, who are
respectfully requested to forward to the Secretary for London an accurate list
of all such names with as little delay as possible.

Unless intimation to the contrary be given to the Secretary for London, the
future deliveries will be made in accordance with the delivery of the first
volume.

LIST OF SUBSCRIBERS.

Academy, Royal Irish

Adam, Thomas, esq. Saville green, Halifax

Adlard, C. and J. Bartholomew close

Ainslie, W. esq. Woodhill, by Ripley, Surrey

Alder, Joshua, esq. Newcastle-on-Tyne

Aldridge, James, m.p. Cheltenham

Alford, H. esq. Taunton

Alison, W.P. Professor, m.p. Edinburgh

Allanson, J. esq. Infirmary, Leeds

Allardyce, Dr. Cheltenham

Allcard, John, esq. r.1.s. &c. Stratford green, Essex
Allchin, W. H., esq. m.s. University College

Allis, Thomas H., esq. York

Allman, Professor, Dublin

Amicable Book Society, Lancaster

Ansted, D. T. esq. m.A. F.R.8. Professor of Geology, King’s College
Anthony, John, esq. Caius College, Cambridge

Archer, F. esq. Liverpool

Ashmolean Museum, Oxford

Atkinson, Rev. J. C. p.a. 7, Victoria place, Scarborough
Austin, R. A. C. esq. sec. 6.5. &c. Merrow, Guildford, Surrey

Babington, C. C. esq. M.A. F.L.S G.S. &c. St. John’s College, Cam.
Babington, C. esq. B.A. St. John’s College, Cambridge
Backhouse, W. J. esq. Darlington

Backhouse, T. J. esq. Sunderland

Bailey, — esq. Museum of Economic Geology

Baird, Rev. John, Yetholm, Roxburgshire

Baird, W. u.p. British Museum

Baker, Robert, esq. Writtle, Essex

Balfour, Professor, m.p. F.L.s. Edinburgh

Ball, John, esq. B.A. M.R-1.A. &c. 85, Stephen’s green, Dublin
Ball, Robert, esq. M.R.1.A. 5, Granby row, Dublin

Balloch, Robert, esq. 177, West Regent street, Glasgow
Banks, Dr. Dublin

Barf, A. esq. 7, Paradise place, Hackney

Barnes, Rev. H. F. Ryde, Isle of Wight

Barker, T. esq. Surgeon, York

Barrow, Peter, esq. 7, Clifford street, Manchester

Bartlett, J. P. esy. Kingston Rectory, near Canterbury

10

Bates, H. Walter, esq. Leicester

Battersby, Dr. Torquay

Baxter, W. esq. Botanic garden, Oxford

Bayton, Rev. W.S. Chichester, Sussex

Beadon, W. jun. esq. Taunton

Bean, W. esq. Scarborough, Yorkshire

Bearpark, G. E. esq. 74, East street, Leeds

Beatty, Professor, T, E. m.D. M.r.1.4. Merrion square, Dublin

Belfast Library, Natural History Society

Bell, J. T. esq. 10, Northwick terrace

Bell, Matthew, esq. m.P. F.H.s. &c. Grosvenor crescent, Belgrave sq.

Bell, Professor, F.R.s. 1.8. 6.5. &c. New Broad street, City

Bell, Robert, J. esq. Mickleover House, near Derby

Bell, Miss, East Shafto, by Morpeth, Northumberland

Bennett, James Risdon, m.p. 24, Finsbury place

Bennett, J. I. esq. F.R.S. F.Z.S. SEC. L.S. &c. British Museum

Benson, John, esq.

Bentley, S. esq. Birmingham

Bergin, T. esq. M.R.1.A. President of the Microscopical Society, Dublin

Berkeley, Rev. M. J. m.a. F.1.s. &c. King’s Cliffe, Wansford

Bidwell], H. esq. Wellington, Salop

Bird, George, esq. Tollerton, near Alne Station, Yorkshire

Birkbeck, H. esq. Keswick, near Norwich

Birkbeck, Morris, esq. Bradford, Yorkshire

Birmingham Library

Blackie, W. G. esq. Villa-field Printing Office, Glasgow

Blackwall, John, esq. Oakland, near Llanrwst, Denbighshire

Bladon, James, esq. Pontypool

Blood, J. Howell, esq. White Hall, Witham, Essex

Blount, J. H. esq. Birmingham Dispensary

Boase, —, esq. Truro, Cornwall

Bodenham, F. S. esq. Hereford

Bodley, T. esq. F.e.s. Pittville, Cheltenham

Bompas, Charles S. esq. Bristol

Bold, T. J. esq. 24, Cloth Market, Neweastle-on-Tyne

Bonar, Miss, Kimmerghame, or 1!, Chester place, Regent’s park

Boniville, A. C, de, esq. Corpus Christi College, Cambridge

Borrer, W. esq. F.x.s. L Ss. &c. Henfield, Sussex

Botfield, J. B. esq. m.P. F.R.S. u.s. &c. 9, Stratton street

Bowerbank, E. S. esq. Sun street, Bishopsgate

Bowerbank, J. S. esq. F.R.s. G.s. &c. 45, Park street, Islington

Bowman, William, esq. Golden square

Bowman, James, esq. Halifax

Boyd, J. C. esq. Liseard, Cheshire

Brackenridge, G. W. esq. F.s.A. G.s. &c. Bromwell House, Brislington,
Bristol

Bramley, L. esq. Halifax, Yorkshire

Bransby, Rev. John, M.A. F.u.s. c.p.s. &e. Lynn, Norfolk

Branton, John, esq. Bush Hall, near Hatfield

Bree, Robert Charles, esq. Stowmarket, Suffolk

Brightwell, T. esq. F.u.s. Norwich

Brisbane, Sir T. M. Bart. k.c.8. K.C-H. D.C.L. P.R.S.E. &c. Mackers-
town, near Kelso

i

Bristol Microscopical Society

Broderick, W. esq. Belford

Brodhurst, B. esq. London Hospital

Bromfield, W. A. m.p. Ryde, Isle of Wight

Broome, C. E. esq. 1, Chesterfield place, Clifton, Bristol
Broughton, Rev. D. The Cliff, Nantwich

Brown, C. F. esq. Harrowgate

Brown, Edwin, esq. Burton-on-Trent

Brown, Robert, v.c.L. F.R.s. v.p.u.s, &c. British Museum
Brown, R. esq. m.R.c.s. Preston, Lancashire

Brown, Isaac, esq. Hitchin, Herts

Browne, W. M. esq. Westminster Fire Office, King st. Covent garden
Brydges, J. H. esq. r.1.s, &c. Boultibrooke, Presteign, Radnorshire
Buchanan, Walter, esq. Suffolk place, Hyde park gardens
Buckley, Nathaniel, m.p. Rochdale

Buckman, J. esq. Medical Hall, Cheltenham

Buckton, G. B. esq. Oakfield Lodge, Hornsey, Middlesex
Budd, Geo. Dr. Dover street, Piccadilly

Budd, William, m.v. Bristol

Budd, — m.p. Plymouth

Bull, J. esq. Godalming

Burlington, Lord, 10, Belgrave square

Burton, John, esq. Croom’s hill, Greenwich

Busk, George, esq. Dreadnought Hospital, Greenwich
Butler, William, esq. Witham, Essex

Byerley, J. esq. Upper Woodside, Cheshire

Callwell, Robert, esq. m.n.1.4. Herbert place, Dublin
Canino, The Prince of

Carr, William, esq, Hurst cottage, Blackheath park, Kent
Carr, W. esq. M.R.c.s. Lee

Carpenter, W.B. m.p. F.r.s. Fullerian Prof. Royal Inst.
Cary, Walter, esq. Chelt hill, Cheltenham

Carter, J. esq. Petty Cury, Cambridge

Catlett, — m.p. Taunton

Chadwick, C. m.p. Leeds

Chambers, R. esq. Edinburgh

Chandler, A. T. esq. Godalming

Chandler, Mrs. Bramley, near Guildford

Children, J. G. esq. F.R.S 8.A. L.s. &c. Torrington square
Christie, Dr. John, Keith, Banffshire

Church, John, esq. Woodside place, near Hatfield, Herts
Clapp, William, esq. Dreadnought Hospital, Greenwich
Clark, Rev. J. D. the Hall, Belford
Clark, H. esq. Corpus Christi College, Cambridge

Clark, Rev. Professor, m.p. Professor of Anatomy, Cambridge
Clarke, Rev. Benjamin, J. Tuam, Ireland

Clarke, W. B. m.p. 26, Dockwray square, North Shields
Clarke, H. G. u.p. Berwick-upon-Tweed h

Clay, Mrs. P. Newwater Haugh, Berwick-upon-Tweed
Clear, William, esq. Cork

Cleaver, Mrs. H. Sissinghurst

Clifford, Rev. F. C. Elden Rectory, near Thetford, Suffolk

12

Clifton, A. C. esq. Welwyn, Herts

Clifton, James, esq. Stoneport, Worcestershire

Coates, John, esq. surgeon, Rochdale

Collingwood, F. J. W. esq. Glanton Pyke, Whittingham, Northumb.

Colquhoun, Dr. Glasgow

Conyngham, Lord Albert, k.c.u.F.s A. &c. Bourne place, Canterbury

Conway, P. L. esq. Burton-under-Needwood, Litchfield

Cooper, W. W. esq. St. John’s College, Cambridge

Cooke, James, esq. Lanesend Cottage, Melksham, Wiltshire

Cooke, W. R. esq. Burford, Oxon.

Copeman, G. esq. Coltishall, near Norwich

Cornwall Library, Truro

Corsellis, ©. C. mp. Asylum, Wakefield

Cottingham, E. esq. surgeon, Bexley, Kent

Cotton, John, esq. Doogulloch Station, River Goulbourn, Port
Phillip, Australia

Crampton, Sir Philip, Dublin

Cresswell, Rev. R. Salcombe Vicarage, Sidmouth

Croker, Dr. C. P. m.z.1.a. Merrion square, Dublin

Crosse, J. G. esq. Norwich

Crotch, Rev. —, Taunton

Cruickshank, Alexander, esq. 12, Rose street, Aberdeen.

Cullen, W. H. w.p. Sidmouth

Cumming, H. esq. 80, Gower street

Cuthbertson, Donald, esq. u.u-B. 10, Fife place, Glasgow

Currer, Miss, Eshton Hall, Yorkshire

Currie, Robert, esq. Newcastle-on-Tyne

Curtis, — esq. Harrow

Cutler, Miss, Budleigh Salterton, Devonshire

Dale, J. C. esq. M.A. F.L.S. c.P.s. &c. Glanville’s Wooton, Sherborne
Dalyell, Sir J. Graham, bart. Hanover street, Edinburgh
Dalrymple, John, esq. 56, Grosvenor street, Bond street
Dalrymple, D. esq. Norwich

Dallachay, Mr. John, Haddow-house, Aberdeen

Darwin, C. esq. Down, Kent

Daubeny, Professor, M.D. F.R.S. G. S. &c. Oxford

Davies, Mrs. St. Leonard’s place, York

Davies, W. M. esq. Liverpool

Davey, H. esq. Beccles, Suffolk

Davis, Robert, esq. York

Dawes, J. S.esq. F.c.s. West Bromwich, Staffordshire

Day, Dr. 3, Southwick street

Deane, Henry, esq. Clapham common

De la Beche, Sir H. F.r.s. 6.s. &e. Craig’s court

Dennes, G. E. esq. F.u.s. &c. Vine street, Golden square
Denny, H. esq. Leeds

Devon and Cornwall Natural History Society

Dickinson, Joseph, m.p. 24, Great George square, Liverpool
Dickenson, William, esq. North Mosses, Whitehaven, Cumberland.
Dickie, George, m.p. Lecturer on Botany, Aberdeen
Dickson, Dr. Curzon street, May Fair

Dillwyn, L. L. esq. Parkwern, Swansea

13

Dilke, C. Wentworth, esq. 76, Sloane street
Doubleday, Edward, esq. F.L.s. &c. British Museum
Douglas, F. m.p. Kelso

Douglas, R. C.esq. Corpus Christi College, Cambridge
Dover Proprietary Library

Dowell, E. W. esq. Swaffham, Norfolk

Dublin, Royal Society

Duncan, P. esq. M.A. F.G.s. &c. Museum, Oxford
Dundas, Mrs. Beechwood, Murrayfield, Edinburgh
Dunnett, James, esy. Bury St. Edmunds

Ducane, Captain r.n. Branted park, near Witham
Dyce, Dr. 198, Union street, Aberdeen

Eddison, Booth, esq. 14, High pavement, Nottingham

Edgeworth, — M. P. esq 1, North Audley street

Edlin, Dr. Ed. Umbala, India

Edwards, F. C. esq. 2, John street, Downshire Hill, Hampstead

Edwards, Thomas, esq.

Egerton, Sir P. G. Bart mp. F.r.s. G.s. &c. Oulton park, Cheshire

Elliott, John, esq. Kingsbridge

Ellison, K. esq. surgeon, Liverpool

Elsey, J. R. esq. Bank of England

Elwes, John, esq. Bossington house, Stockbridge, Hants

Embleton, Robert,esq. Embleton, near Alnwick

Embleton, Dr. Newcastle ;

Enniskillen, The Earl of, p.c.u. F.R.8. 6.8. &c. Florence court,
Enniskillen

Evans, Mrs. Shenley hill, Herts, & 72, Oxford terrace, Edgeware rd.

Ewing, Rev. Thomas

Eyton, T.C. esq. F.G.S. z.8. &c. Eyton Hall, Shrewsbury

Falconer, Dr. W. Tenby, South Wales

Falconer, Dr. H. r.c.s. 23, Norfolk street, Strand

Farre, Dr, Frederic, Bridge street, Blackfriars

Farren, Charles, m.p. Dublin

Fellows, Sir C. 30, Russell square

Fennell, James H. esq. 15, Paris street, New road, Lambeth
Ferguson, Wm. esq. 18, Wharton street, Lloyd square
Fielding, Geo m.D. F.R.S. &c.

Fielding, G. H. esq. Lenham lodge, Kent

Finsbury Medical Book Society, 2, St. Mary Axe

Fitton, E. B. esq. 53, Upper Harley street

Fitton, William H. m.p. F.R.s. &c. 53, Upper Harley street
Fitton, W. J. esq. B.A. Trinity College, Cambridge
Fitzwilliam, Earl

Fleming, Dr. Manchester

Fletcher, Rev. C. Southwell, Nottingham

Fletcher, Bell, m.p. Birmingham

Flower, J. W. esq. 61, Bread street, City

Forbes, Professor Edward, F.R.s. &c. King’s College, London
Forbes, J. M.p, F.R.S. F.L.S. &c. Old Burlington street
Forster, Edward, Esq. F.R.S. v.p.u.s. &e. Mansion House street
Fox, Rev. Darwin, Delamere Rectory, Chester

14

Fox, George T. esq. F.R.s. c.s. &c. Durham
Frampton, Dr. A. New Broad street, City

Freeborn, J. J. S. esq. 38, Broad street, Oxford
Frere, H. T. esq. Corpus Christi College, Cambridge
Fry, J. S. esq. 2, Charlotte street, Park street, Bristol
Fryer, J. H. esq. Whitley House, Northumberland
Fuge, J. H. esq. F.R.c.s.e. Plymouth

Fyfe, W. W. esq. Berwick-on-Tweed

Fysh, Rev. Frederick, Marina house, Torquay

Gall, A. C. esq. Ripley, Surrey

Gandy, J. H. esq. Trinity College, Cambridge

Gardner, Samuel J. esq. Sheffield

Garnons, Rev. L. P. 3.o Sidney College, Cambridge
George, Richard F. esq. Gay street, Bath

Giles, James, esq. The Elms, Lancaster

_ Gibson, G.S. esq. Saffron Walden, Essex

Gillett, W. E, esq. Freshwater House, near Taunton
Glasgow Philosophical Society

Goadsley, Edward, esq. Albert place, Manchester
Goatley, Thomas, esq, Chipping Norton, Oxon
Goldsworthy, J. H. esq. High street, Stepney

Goodsir, Harry D. S.esq. R.N.

Goodsir, John, esq. College Museum, Edinburgh
Gordon, Rev. George, Manse of Birnie, by Elgin, N.B.
Gordon, P. L. esq, Craig Myle, Aberdeen

Gott, William, esq. Leeds

Gott, John, esy. Wither, near Leeds

Gough,G S. esq. M.x.1.4.Gren. Gds. 45, Park st. Gros. sq.or Atheneum
Gould, John, esq. F.R.S. LS. z.s. & 21, Broad st. Golden sq.
Gourlie, William, J. esq. 8, South Frederick st. Glasgow
Grainger, R D. esq. F.rR.s. &c. &c. Anerley, Norwood
Gratton, James, esq. Shoreditch

Gray, John, esq. Greenock

Gray, William, jun. esq. York

Gray, T. esq. 20, Monteith row, Glasgow

Greenhill, Dr. Oxford

Greening, William, esq. Marlborough place, Kent road
Greenwood, Alfred, esq. Chelmsford, Essex

Gretton, Rev. H. Nantwich Rectory, Cheshire

Greville, R. K. LL.D. F.R.S.E. &c. George’s square, Edinburgh
Grifith, William, esq. Calcutta ©

Griffith, Mrs. Torquay

Griffiths, —, esq. Ireland

Gruggen, J. B. esq. surgeon, Chichester

Grut, N. esq. F.R.S.E. &c. 5, Inverleith row, Edinburgh
Gurney, J. H. esq. Earlham, near Norwich

Gull, Dr. Guy’s Hospital

Hailstone, S. esq. F.u.s. Horton Hall, near Bradford, York
Haines, Dr. 26, Warren’s place, Cork

Hall, John, esq. West road, Congleton

Hall, C. R. m». Holmes Chapel, Cheshire

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Hall, N. esq. Wortley, near Leeds

Hamilton Rev. James, 7, Lansdown place, Brunswick square
Hancock, John, esq. Newcastle-on-Tyne

Handford, George C. esq. Cheyne walk, Chelsea

Hands, Benjamin, esq. Hornsey, Middlesex

Hanley, Sylvanus, esq. Newington green

Hanson, Samuel, esq. 15, Trinity square, Tower hill

Hanson, William, esq. Reigate

Hardwicke, William, esq. Calthorpe street, Gray’s inn lane
Hardy, James, esq. 7, Mulgrave terrace, Gateshead

Harley, James, esq. Leicester

Harley, F. esq. Cortling stock, Nottinghamshire

Harrinson, J. esq. Reading Jas
Harrison, Rev. J. B. Barham, near Canterbury

Harrison, Dr. Cork, Ireland

Hartshorne, Rev. C., Rectory, Northampton

Harvey, J. R. m.v. 18, St. Patrick’s place, Cork

Harvey, W. H. esq. Trinity College, Dublin

Hastings Literary and Scientific Society

Haywood, J. W. esq. :
Head, Edward, esq. Mr. Crossing’s, 15, Morrice square, Devonport
Henderson, W. T. esq. London and Westminster Bank, Lothbury
Henderson, Thomas, esq. South Dispensary, Liverpool

Henfrey, Arthur, Esq. r.u.s. &c. Museum of Economic Geology
Henslow, Professor, Cambridge

Hepburn, Sir T. B. m.r. Smeaton, Preston Kirk, N.B.

Hepburn, Thomas B. esq. Shabden park, Chipstead, Reigate
Hepburn, A. esq. Whittingham, near Preston Kirk, Mid Lothian
Heppenstall, John, esq. Upper Thorpe, near Sheffield

Herbert (see Manchester, Dean of)

Heslop, R. C.m.p. Preston, Lancashire

Hetling, E. esq. Bristol

Hewetson, J. esq. Corpus Christi College, Cambridge

Hewlet, George, esq. Harrow

Hey, Samuel, esq. Leeds

Heysham T. C. esq. Carlisle

Higginbotham, J. esq. F.R.c.s. Nottingham

Higgins, C. H. esq. Taunton

Hill, W. T. esq. Portwood hall, near Stockport

Hinckes, Rev. William, Hampstead

Hindle, James, esq. Norton, near Doncaster

Hitch, J. W. m.p. Gloucester

Hodgson, H.B. esq. Acomb House, York

Hodson, Joseph, esq. surgeon, Birmingham

Hodgkin, Dr. Lower Brook street

Hogg, J. esq. 12, King’s Bench walk

Holland, William, esq. Light Cliff, near Halifax, Yorkshire
Holt, George, esq. Liverpool

Hore, Rev. W.S. m.a. F.u.s. &c. 30, Trafalgar pl. Stoke, Devonport
Horne, C. esq. Clapham common

Horner, Leonard, esq. 2, Bedford row

Horrocks, Miss E. M. Antermony house, Lennox town, Glasgow
Horsfield, Dr. F.r.s. u.s. 6.s. &c. India house, London

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Howell, —, m.D. F.R.s.E. Deputy Inspector of Hospitals, Bristol
Howells, J. esq.

Howitt, Thomas, esq. Lancaster

Hoyer, J. esq. Crown court, Threadneedle street
Hudson, Anthony, esq. Norwich

Hudson, E. D. esq. Little Thorpe, near Leicester
Hudson, R. esq. F.R.S. e.s. &c. Clapham common
Holme, Dr. Edward, Manchester

Humphries, Edward, esq. surgeon, Kingsland
Hunter, M. esq. 22, Artillery place, Finsbury
Huntingdon, Frederick, esq. Hull

Husband, W. D. esq. surgeon, York

Hutton, Thomas, esq. F.6.s. M.R.1.A. &c. Dublin
Huxley, James Edward, m.p. Gloucester
Hyndman, George C. esq. Belfast

Ibbotson, S. L. B. esq. 22, Upper Phillimore place, Kensington
Image, Rev. Thos, a.m. F.@.s. &c. Whepsted, near Bury St. Edmunds
Ingham, Robert, esq. M.A. F.G.S. &c, Westoe -

Inglis, James, m.p. Halifax, Yorkshire

Inman, Dr. Thomas, Liverpool

Tpswich Philosophical Society

Irvine, Hans, esq. m.s. Dublin

Isaacson, W. esq. Huntingdon

Jackson, Dr. Oxford

Jackson, H. esq. James’s row, Sheffield

James, Captain R. E. Dublin

Janson, Joseph, esq. F.L.s. 32, Abchurch lane

Jardine, SirW.Bart.r.2.s.E.1.s. &e. Jardine hall, Lockerby, Dumfries
Jefferson, J. esq. St. John’s College, Cambridge

Jeffreys, J. G. esq. F.R.S. L.8, &c. Swansea

Jenyns, Rev. L. m.A. F.L S. c.e.s. &c. Swaffam Bulbeck
Jepson, W.m.p. 80, Chapel street, Salford

Jerdon, Archibald, esq. Lintalee by Jedburgh

Johnston, George, M.D. LL.D. F.R.C.S.E. Berwick-upon-Tweed
Jones, Capt. m.p. F.c.s. &c. 30, Charles street, St. James’s
Jones, — esq. 23, Soho square

Johnson, J. W. esq. Ipswich

Joy, Thomas, esq. 10, St. Giles’s street, Oxford

Jubb, Abram, esq. surgeon, Halifax

Juman, Dr. Liverpool :

Kane, W. esq. B.A. T.c.D. Exmouth

Kay, David, m.p. Bradford, Yorkshire

Keenlyside, R. H. m.p. Stockton-on-Tees

Kelaart, Dr. 40, Bryanstone Street, Portman Square
Keman, J. esq.

Kennedy, J. m.p. Woodhouse, near Loughborough
Kenrick, Miss, Stonehouse, near Canterbury

Kernon, Thomas, esq. Avebury house, Marlborough, Wilts
King, R. L. esq. Rev. Dr. Tancock’s, Truro, Cornwall
King, John, esq. Ipswich

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King, Richard, m.p. Sackville street

King, Henry, Castle gate, York

Kirby, T. B. esq. Leicester

Kirkman, Dr. Walton, near Woodbridge, Suffolk
Kitching, Alfred, esq. 57, Myton gate, Hull
Kitching, John, esq. Darnell hall, near Sheffield
Kitching, W. V. esq. St. John’s College, Cambridge
Knapp, Dr. 9, Duncan street, Edinburgh
Knapp, A. C. esq. 10, Paragon, Clifton
Knowles, Professor C. B. Birmingham

Koninck, L. de, esq. Liége

Lacy, E. esq. m.R.c.s. &c. Poole, Dorset

Landsborough, Rev. D. Park-end, Saltcoats, Ayrshire

Lane, E. esq. Plymouth

Langmore, Dr. 40, Finsbury square

Langmore, W. B. esq. 4, Christopher street, Finsbury square
Langstaff, J. esq. 9, Cambridge square, Hyde park

Lankester, E. m D. F.R.S. L.S. &c. 22, Old Burlington street
Laycock, Dr. C. R. 5, Adelaide road, Haverstock hill
Leckenby, John, esq. Scarborough, Yorkshire

Lee, Dr. F.R.S. F.R.A.s. &c. Hartwell, near Aylesbury, Bucks
Lee, Rev. James P. King Edward’s School, Birmingham

Lee, W. S. esq. Morningside, near Aberdeen

Leeson, Dr. Greenwich

Leighton, Rev. W. A. ».A. F.R.S.E. &c. Luciefield, Shrewsbury
Leslie, James, esq. Chanonry, Old Aberdeen

Leyland, E. esq. Corn market, Halifax

Lindley, Professor, D. PH. F.R.s, &c. 21, Regent street
Lingin, Charles, m.p. Hereford

Lingwood, R. M. esq. m.A. F.L.s. &c. Lyston house, Ross, Hereford
Lister, J. J. esq. F.R.s. Upton, near Stratford, Essex

Little, Rev. William, Manse, Kirkpatrick, Moffat

Litton, Professor, M.D. R.D.S. &c. Dublin

Liverpool Library, Lyceum

Liverpooi Medical Institution

Liverpool Royal Institution

Lizars, W. H. esq. St. James’s square, Edinburgh

Lizars, Professor A. J. m.p. 17, King street, Aberdeen
Llewellyn, — esq. Swansea

Lloyd, William Horton, esq. F.u.s. z.s. &c. Park square, Regent’s park
Loftus, W. K. esq. Caius College, Cambridge

London Institution, Finsbury circus

Longchamps, M. de Selys, Liege

Lovejoy, S. esq. Reading

Loughton, W. Gore, esq. Hatch court, near Taunton

Lowe, James, esq. Liseard Vale, Cheshire

Luard, William W. esq. Witham lodge, Witham, Essex
Ludlow Natural History Society

Lye, James Black, m.p. Hereford

Lyell, Charles, m. F.r.s. 1.5. 6.8. &c. 16, Hart street, Bloomsbury
Lyle, Mrs. Acheson, Dublin

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Macdonald, Alexander, esq. 5, Regent terrace, Edinburgh
Macdonald, W. B. esq Rammerscales, Lochmaben

Mackay, Dr. G. 26, East Emma place, Stonehouse

Mackey, G. Y. esq. Curator of the Coll. Botanical Gardens, Dublin
Mackintosh, George, esq. Campsie, near Glasgow
Mackintyre, Dr. ¥ u.s. Hackney

Mackenzie, Skelton, esq. LL.n. Dublin

Maclagan, Douglas, m.p. F.R.s.E. 129, George street, Edinburgh
Maclagan, P. W. m.p. Assistant Surgeon in the Army, Canada
Maelagan, Lieutenant Robert, Royal Engineers

Macmeikan, John, esq. London Hospital

Mac Taggart, D esq. Halifax

Manchester Natural History Society

Manchester, The Hon. and Rev. Dean of, Spofforth, Yorkshire
Marshall, Matthew, esq. Bank of England

Martin, Dr. Glendale, Isle of Skye

Martin, Dr. Adam, Rochester, Kent

Matteson, William, jun. esq. surgeon, York

Maund, Benjamin, esq. Broomsgrove, Worcestershire
Maxwell, Wellwood, esq. Munshes Castle, Douglass

Mc Andrew, R esq. Liverpool

Meggy, George, esq Chronicle Office, Chelmsford

Melrose, Jonathan, esq. Writer, Coldstream, Berwickshire
Mercer, James, M.D. F.R.C.S.E. 50, Northumberland st, Edinburgh
Melville, Alex. esq. Assist. Demonst. of Anatomy, Univ. Edinburgh
Meredith, W, L. m.p. Cork

Meynell, Thomas, esq. York

Miller, O. T. esq. Royal Marine Infirmary, Plymouth

Miller, George, esq. M.R.c.s.E. Emsworth, Hants

Mitchell, Alexander, esq. 20, Upper Kirk gate, Aberdeen
Mitchell, E. W. Esq. 28, Great Russell Street, Bloomsbury
Mitchell, D. W. esq. 5, Mortimer street, Cavendish square
Mitchell, Dr. Mauchline, Argyleshire, N.B.

Mitford, Captain, Hunmanby, Yorkshire

Moggridge, Matthew, esq. Swansea

Moon, William, esq. surgeon, Tottenham, Middlesex

Moore, J.C. esq. 37, Hertford street, May Fair

Moore, John, esq. Leicester

Mordaunt, John, esq. Ashton Water, near Bristol -

Morley, George, esq. Leeds

Morris, Beverley, R. A.B. m.p. Beverley

Mullinix, — esq. 7, Adelphi terrace

Munford, Rev.George, East Winch Vicarage, Lynn

Munn, W.A. esq. Throwley house, Faversham, Kent

Munro, Miss, Fritham, Stoney cross, Hants

Murchison, R.I. esq. r.r.s. &c. Belgrave square

Murdoch, W.m.p 320, Rotherhithe street

Murray, Patrick, m.p. Scarborough, Yorkshire

Nasmyth, Alex. esq. Fr L.s. 6.8. &c. 13, George st. Hanover square
Naylor, G. F. esq. Asylum, Wakefield i
Needham, J. esq. F.L.s. Leicester

Neill, Patrick, uL.D. F.R.S.E. 1.8, &c. Cannon Mills, Edinburgh

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a ee ne li = oe a —

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Nelson, Jno. G. esq. Colchester, Essex

Neville, Henry, esq. Hervey hill, co. Londonderry, Ireland
Newbold, W. W. esq. B.A. Sharrow Bank, Sheffield
Newcastle Literary and Scientific Society

Newman, Edward, esq. F.u.s. 9, Devonshire street, Bishopsgate
Newnham, W. O, esq. St. John’s College, Cambridge
Newnham, William, esq. Farnham, Surrey

Newport, George, esq. F.R.S. Southwick st. Cambridge ter.
Norfolk and Norwich Literary Institution

Norman, George, esq. F.G s. &c. Beverley road, Hull
Norris, Henry, esq. South Petherton

Northampton, the Marquess of, p.r.s. &c. 145, Piccadilly
Norwich, the Lord Bishop of

Nunneley, Thos. esq. Surgeon, Leeds.

Nutford, Capt. Hunmanby, Yorkshire

Ogilby, W. esq. Upper Gower street

Ogilvie, J. F. esq. Morningside Lunatic Asylum

Oldham, Professor, Dublin

Ollivant, Dr. Trinity College, Cambridge

Otter, Captain, Hydrographic Survey

Owen, Professor, F.R.S. L.s. &c. Royal College of Surgeons

Palmer, Dr. S. Birmingham

Parker, C. L. esq. Oxford

Parkinson, esq. F.1.s. Cambridge terrace, Hyde park
Parnell, R. m.D. F.R.s.e. &e. 50, Rankeilor street, Edinburgh
Partridge, Richard, esq. F.R s. King’s College, London
Pattisson, Jacob H. esq. tu.s. Witham House, Witham
Pattisson, W. H. esq.

Patterson, Robert, esq. Belfast

Paxton, Jas. m.p. Rugby

Peachey, W. jun. esq. Ebernoc, near Petworth, Sussex
Pearce, J. C. esq. Bradford, Wilts, near Bath

Pease, Mrs. Feetham, near Darlington

Percival, W. esq. Ist Life Guards, Hyde Park Barracks
Pereira, J m.p. F.R.s. &c. Finsbury square
Percy, Edmund, esq. Nottingham

Percy, J.m.p. Birmingham

Phelps, Rev. H. D. Snodland rectory, West Malling, Kent
Phillips, Professor John F.r s. York

Pigg, Thomas, jun. esq. 7, Ridley place, Newcastle-on-Tyne
Pinder, Rey. George, Sedburgh, Yorkshire

Plant, John, esq Leicester

Player, Mrs. Tenby, South Wales

Playfair, Lyon, Dr. Museum Economic Geology

Plomley, James F. esq. Rye, Sussex

Plomley, Francis, m.p. Ph.D. F.s.A. &c. Lydd, Romney Marsh, Kent
Pollexfen, Rev. J. H. Bradford, Yorkshire

Popham, John, m.p. Cork

Potts, W. J. esq.

Powell, Hugh, esq. Clarendon street, Somers Town

Power, Rev. Josh. m.a. Librarian of the University, Cambridge

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Power, Thomas, m.p. St. Patrick’s hill, Cork
Pratt, S. P. esq. 53, Lincoln’s inn fields

Preston Literary and Philosophical Society
Prestwich, Joseph, jun. esq. Mark lane

Price, William, esq. Leeds

Price, Thomas T. esy Surgeon, Hereford
Pritchard, A. esq. 3, Canonbury lane, Islington
Prower, Rev. 3. M. Purton, near Swindon, Wilts

College Hospital

Quain, Richard, m.p. a
ellclose square

Quekett, E. J. esq. F.L.s. 50,

Raban, R.B. Captain, r.n. Hatch Beauchamp, near Taunton

Radcliffe Library, Oxford

Rankin, Robert, esq. Hastings, Sussex

Ranking, W. H. m.p. Bury St. Edmunds

Ransome, Robert, esq. Ipswich

Raper, W. A. m.p. Parade, Portsmouth

Rattray, W. esq. St. Nicholas street, Aberdeen

Rawson, T. W. esq. Halifax, Yorkshire

Ray, George, esq. Milton, near Sittingbourne, Kent

Ray, John, esq. Heanor Hall, Derbyshire

Reade, Rev. J. B. Stone Vicarage, near Aylesbury, Bucks

Reid, F. G. u.p. Hertford

Reid, John, m.v. St. Andrews

Reeve, Lovell, esq. A.L.s. &c. King William street, Strand

Reckitt, William, esq. m.A. &c. High street, Boston, Lincolnshire

Reigate Institution, Reigate, Surrey

Reynolds, Henry, esq. 42, Moorgate street

Richardson, John, m.D. F.R.s. 1.5. &c. Haslar Hospital, Gosport

Ringrove, John esq. Potters Barr

Robb, James, m.p. Prof. Nat. Hist. King’s College, Frederickton,
New Brunswick

Robertson, W. esq. F.z.8. Neweastle-on-Tyne

Robertson, W. H. m.p. Buxton, Derbyshire

Robertson, John, esq. Duffield Bank house, Derby

Robinson, Rev. George, Armagh

Rohloff, — esq. Plymouth

Rolfe, Rev. S. C. E. N. Heacham Hall, Lynn, Norfolk

Ross, Andrew, esq. 21, Featherstone buildings, Holborn

Rothery, H. C. esq. 2.A. 10, Stratford place

Rowntree, J. esq. Scarborough:

Royle, Prof. J. F. m.D. F.R.S. L.S. 6.8. &e. 4, Bulstrode street,
St. Marylebone

Rudd, E. J. esq. Halifax, Yorkshire

Russell, F. esq. Brislington, Bristol

Russell, James, m.p. Philosophical Institution, Birmingham |

Russell Medical Book Society |

Rutherford, W. esq.

Ryder, Charles, esq. Stamp and Taxes Office, Somerset House

Sabine, W. esq. B.A. Jesus College, Cambridge |
Sabine, Colonel | |
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Salmon, John D. esq. Godalming

Salmon, R. esq. Downham, Norfolk

Salter, T. Bell, m.p. F.u.s. Ryde, Isle of Wight

Salter, H. H. esq. King’s College

Sandwith, Humphrey, m.v. 1, Albion street, Hull

Satterfield, Joshua, esq. Manchester

Saull, W. D. esq. F.a.s. a.s. &c. 15, Aldersgate street

Say, Rev. F.H.S. Braughing Vicarage, Ware, Herts

Sayle, George, esq. King’s Lynn

Seager, J. L. esq. Millbank, Westminster

Searle, George, esq. Cumming street, Pentonville

Sedgwick, Rev. Professor, F.R.s. &c. Cambridge

Selby, Prideaux J. esy. F.L.S. @.s. &c. Twizel, Northumberland

Sellers, William, m.p. Royal College Physicians, Edinburgh

Semple, Robert H. esq. 3, Hans buildings, Islington

Shaw, Dr. Hophouse, near Boston, Lincolnshire

Shapter, Thomas, m.p. Exeter

Sharp, Henry, esq. Bolton le-Moor, Lancashire

Sheppard, James, m.p. Stonehouse, Devonport

Shuttleworth, Robert James, esq. Berne

Shuttleworth, John, esq. Manchester

Sidney, M. J. F. esq. Cowper, near Morpeth

Simpson, J. Y. m.p. Prof. Midwifery University Edinburgh

Simpson, Samuel, esq. The Greaves, Lancaster

Sion College Library, London Wall

Slaney, W. H. esq. care of T. C. Eyton, esq. Eyton Hall, Shrewsbury

Smith, Alfred, esq. m.rR.c.s. St. Paul street, Portland square, Bristol

Smith, Rev. J. J. m.a. Caius College, Cambridge

Smith, Dr. Pye, Homerton

Smith, Charles, esq. m.R.c.s. Bury St. Edmunds

Smyth, W. H. esq. Caius College, Cambridge

Solly, R. H. esq. F.n.s, 1.8. &c. Great Ormond street, Queen square

Solly, E. esq. F.R s. Bedford row

Sowerby, James de C. esq. F.L.s. z.8. &c. Royal Botanic Garden,
Regent’s park

Spence, W. esq. F.R.8. 1.8. &c. 18, Lower Seymour st. Portman sq.

Spence, Rev. John, East Keal, Spilsby, Lincolnshire

Spicer, J. W. G. esq. Esher place, Esher, Surrey

Spragge, W. K. esq. South Down buildings, Tor, Devonshire

Spragge, F. esq. South Down buildings, Tor, Devonshire

Squire, Lovell, esq. Falmouth

Stallard, J. P. esq. Leicester

Stanger, W. m.p. Cape of Good Hope

Stark, Robert, M. esq. Annandale street, Edinburgh

Statham, Rev. S. F.

Statter, William, esq. Wakefield

Staunton, F. B. esq. 20, Waltham terrace, Merrion avenue, Dublin

Steel, C. W.. esq. Lewisham

Steuart, Sir James, Bart.

Stevens, W. V. esq. Horton, near Slough

Stewart Allan, m.p. 50, High street, Paisley

Stewart, J. Vandeleur, esq. Rockhill, Letterkenny, Ireland

Stock, Daniel, esq. Bungay

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Stocks, J. C. esq. Bombay Residency, India

Stokes, W. R. esq. Shrewsbury

Stokes, Charles, esq. F.R.S. a.s. &c. 4, Verulam buildings, Gray’s Inn
Strickland, Hugh E, esq. m.a. F.G.s. &c. 39, Holywell, Oxford
Strickland, Arthur, esq. Bridlington Quay, Yorkshire
Strickland, J. H. esq. 22, North Audley street

Streeten, R. J. N. m.p. Worcester

Sweetlove, J. esq. Liverpool, Nat. Hist. Soc.

Swineard, Frederick, esq. Precentor’s court, York
Subscription Library, Bromley house, Nottingham
Sutherland, Captain G. M. Shilden hall, Halifax

Tancred, Sir Thomas, Bart. Shotley hill

Tate, George, esq. F.G.s. Alnwick, Northumberland
Tatham, John, esq. jun. Settle, Yorkshire

Taylor, Richard, esq. F.u.s. s.a. &c. Red Lion court, Fleet street
Taylor, Henry, m.p. Nottingham Dispensary

Taylor, Dr. Robert, Edinburgh

Teale, Joseph, esq. Leeds

Teale, T. P. esq. Leeds

Tennant, James, esq. F.G.s. &c. 149, Strand

Theakstone, J. W. esq. Scarborough, Yorkshire
Thomas, W. L. esq. Hatfield

Thomas, Henry, esq. Sheffield

Thompson, Thomas, esq. M.A. F.R.S. &c. Solicitor, Hull
Thompson, W. esq. Pres. Nat. Hist. Soc. Belfast
Thompson, Theophilus, m.p. Bedford square, London
Thompson, George, esq. Liverpool

Thomsun, R. D. m.p. Glasgow

Thomson, Professor Allen, 26, India street, Edinburgh
Thornhill, J. esq. Lit. and Phil. Soc. Newcastle-on-Tyne
Thornwell, R. esq. Burton-on-Trent

Thorpe, Rev. W. Wormersley, near Pontefract, Yorkshire
Tomkins, C. m.p. Abingdon

Torquay Natural History Society

Torrie, T. J. esq. F.6.s. &c. 21, Royal Circus, Edinburgh
Toswell, ©. 8. esq. 8, Torrington place

Travis, J. H. esq. York

Trinity College, Dublin

Tripe, Dr. Plymouth

Troughton, Nathaniel, esq. Coventry

Tudor, Richard, esq. Bootle, Liverpool

Tuke, W. M. Esq. York

Tuke, James, H. esq. York

Turner Dawson, esq. F.R.S. 8.A. L.S. &c. Yarmouth
Tweedy, M. esq. Alverton, Truro

Twining, William, m.p. 13, Bedford place, Russell square
Twiss, Travers, Dr. Prof. Political Economy Univ. Coll. Oxford.

Varenne, E. G. esq. Kelvedon, Essex
Verneuil, M. Edward de, Paris

Walker, D. esq. m.a. Colchester, Essex

23

Walker, J. jun. esq. Axbridge, near Wells, Somerset
Walker, John, esq Chesterfield
Waller, Edward, esq. Finnow House, Burrisokane, Ireland
Walmsley, V. O. esq. Westwood House, near Wigan, Lancaster
Walton, John, esq. F.u.s. &c. 9, Barnsbury square, Islington
Walton, Richard. esq, Cambridge

Warburton, H. esq. M.P. F.R.S. PRES. G.s. &c. 45, Cadogan pl. Chelsea
Ward, N. B. esq. F.u.s. z.8 &c. Wellclose square

Ward, N. esq. London Hospital

Warington, Robert, esq. Apothecaries’ Hall

Warren, T. W. esy. 40, Blessington street, Dublin
Warwickshire Natural History Society

Waterhouse, G. esq. British Museum

Waterhouse, J. esq. Halifax

Watson, James, m.p. St. Vincent street, Glasgow

Webb, J. E. esq. Bungay

Webster, William, jun. esq Upton, Cheshire

Weddell, Robert, esq. Berwick-on-Tweed

Weeks, Richard, esq. Hampton Lodge, Hurst Pierpoint, Brighton
Welch, R. esq. Huddersfield

Wellbeloved, Rev. C. York

Wells, Robert, esq. 2, Archibald place, Edinburgh

Wells, William, esq. Primrose house, Liverpool

Wharton, Rev. Thomas, Bath, Jamaica

Wheatstone, Professor, King’s College

Wheeler, Mrs. 2, Sussex place, Southampton

Whish, H. esq. Corpus Christi College, Cambridge
White, Adam, esq. British Museum

White, A. D. m p. Winchester

White, C. G. esq. Poplar

White, Alfred, esq. r.u.s. &c. Cloudesley square, Islington
White, H. H. esq. 13, Old square, Lincoln's Inn
Whitehaven Library

Whiting, Josh. B. esq. King’s Lynn, Norfolk

Whitla, F. esq. Belfast

Wickenden, Joseph, esq. Surgeon, Birmingham
Wickham, W. J. esq. Winchester

Wilkinson, M. A. E. m.p. Manchester.

Williams, Rev. J. Euston Glebe, Chorley, Lancashire
Wilson, Charles, m.n. Kelso

Wilson, T. J. esq. Surgeon, Lockerby

Wilson, Edward, esq. Lydstep house, Tenby

Wilson, Dr. 3, Devonport street, Sussex square

Wilton, J. W. esq. Gloucester

Winchester, The very Rev. the Dean of

Windsor, John, esq. F.L.S. F.R.C.S.E. &c. Manchester
Winn, Charles, esq. Nostell, near Wakefieid

Winter, T. B. esq. Cannon place, Brighton

Winterbottom, P. M. m.p. Westoe, S. Shields
Winterbottom, James Edward, esq. r.u.s. &c. Newbury, Berks
Wintle, G. S. esq. Eastgate street, Gloucester

Witham Literary Institution

Wix, Rev. S. F.R.s. A.s. St. Bartholomew’s Hospital

24

Wollaston, T. V. esq. Jesus College, Cambridge

Wollaston, Miss, Clapham common

Wood, S. V. esq. F.a s. &e. 14, Bernard street, Russell square
Wood, Neville, m.p. Lower Belgrave street, Belgrave square
Wood, Samuel, A.m. m.p. Avenue House, Bandon, co. Cork
Wood, Mrs. E. Stout hall, Swansea

Woodd, Basil, T. esq. F.L.s. &c. 14, Great Cumberland street
Woodford, Dr. Taunton

Wooley, J. esq. Trinity College, Cambridge

Wright, G. P. esq. Auburn Cottage, Hawley road, Kentish town
Wright, Thomas, esq. V. P. Philosophical Institution, Cheltenham

Yarrell, William, esq. F.u.s. z.s. &c. Ryder street, St. James’s street
York Philosophical Society

Young, James, esq. Hull

Young, Dr. J. F. r.z s. &c. Upper Kennington lane

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