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THE ROTIFERA.

VOLUME I.

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PRINTED BY
SPOTTISWOODE AND CO., NEW-STREET SQUARE
LONDON

2 THE Je 9 JIB al dab are

OR

(ehhh h-ANIMALCULES,

BOTH BRITISH AND FOREIGN.

BY

C. T. HUDSON, LL.D. Canras., F.R.S.

ASSISTED BY

ES Hy GOSsiy F-R:s!

IN TWO VOLUMES, WITH SUPPLEMENT.

<E NATO
VOLUME I. ae ie

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[2)

WITH ILLUSTRATIONS.

LONDON : SMITHSON ap
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AND NEW YORK: 15 EAST 16 STREET. SEP 2 3 1986
1889.

~AIBRARIES

All rights reserved.

Cecam mihi in cunctis fidem haberi haud postulo; id tantum optans, ut
continua indagatione ac studio mea aliquando confirmentur, aut me a vero aberrasse
demonstretur. Perscrutatoris vel exactissimi, et quamvis summam adhibeat,
attentionem fugere aliquando quedam possunt; et casus nonnunquam fortuito
nobis offert, que intensissima spe cura frustra quesivimus.—J. BasTErR.

C’est dans les livres de la Nature, qu’on doit lire, quand on veut travailler sur
VHistoire Naturelle; mais on ne peut pas y lire, quand on yeut. I] faut des lieux,
des saisons et des circonstances favorables pour faire des observations nécessaires.
Quelques fois 4 la vérité on peut aider & faire naitre des circonstances heureuses,
mais plus souyent il faut que le hazard nous serye.—RbauMUR.

PREFACE.

—0}4400-——.

Nearuy fifty years have passed, since Ehrenberg’s successful invasion of the
unseen world was made known by the publication of his noble work, Die In-
fusionsthierchen ; and twenty-five since Dr. Arlidge’s edition of Pritchard’s excel-
lent History of Infusoria brought together, im a convenient form, the results of
the long and patient observation of many investigators.

Meanwhile memoirs on various species of Rotifera, as well as the number of
species themselves, kept slowly increasing; and, what is of greater moment,
the prolonged study of these interesting atoms, by several acute observers, has
made clear some of the perplexing difficulties in their structure, and swept away
many mistakes both of observation and inference.

Under these circumstances the authors of this work believed that such a
book as the present was much wanted; and they hoped that their prolonged
study of the Rotifera (continued, in the case of each author, almost daily, for
upwards of thirty years), as well as their invariable habit of drawing from life
all that they had observed, would enable them, by means of their long accumu-
lated stores of drawings and notes, to meet this want.

They venture to think, from the manner in which, so far, the book has been
received, that this belief and hope have both been justified ; and in confirmation
of the favourable opinions of it that have already been expressed, would point
out (they trust with pardonable pride) that this work contains more than 120
species which were unrecognized when Dr. Arlidge wrote ; that nearly the whole
of these have been added to science by the authors themselves; that about
eighty of these new species, chiefly among the Ploima, have been found by one of
the authors during the last fifteen months; and that the other by the discovery,
among other remarkable forms, of Pedalion mirum, has put beyond question the
fact that the Rorrrera, in one point at least, are closely linked to the ArTHROPoODA.

The thirty coloured plates have been divided nearly equally between the two
colleagues ; the small uncoloured plates A, B, C are by Dr. Hudson. The figures
in plate D are taken from various sources; but in every case, both here and in
the coloured plates, the original authority has been indicated; the initials G or
H being attached to those figures which have been drawn from the life by Mr.
Gosse or Dr. Hudson. Mr. Gosse’s independent portions of the text are always
inclosed in square brackets [ ], and marked at the end with his initials, P.H.G. :
the portions not so marked are by Dr. Hudson, including the first four chapters.

vi PREFACE.

Throughout the whole of the work Dr. Hudson has had the invaluable assistance
of Mr. Gosse’s MS. notes, and of his close and constant revision of the proofs.

The hearty thanks of the authors are due to Mr. Frank Crisp, one of the
secretaries of the Royal Microscopical Society, and editor of its Journal, for the
great service that he has rendered them by forwarding early notices of all the
pamphlets and papers published on the subject: anyone who is, or has been,
engaged in a task similar to this will know what time and labour have thus been
spared, by his thoughtful kindness.

They are, too, greatly indebted to numerous kind correspondents for living
specimens, often obtained with no little expenditure of time and trouble, and for
the records of their observations on them; as well as for valuable preparations
of rare species, which could not be sent alive: to these correspondents the
authors tender their grateful thanks. In each case where the specimen was new
or rare the name of the place in which it was found, and (when permitted) the
name also of the finder, has been added to the description. They wish, however,
to make special mention of how much they owe to Miss Saunders of Cheltenham,
Miss Davies of Woolston, Dr. F. Collins, and Mr. John Hood of Dundee, for their
constant kindness in sending a profuse number of specimens of many species,
some of which were of unusual interest.

It is so natural to recommend one’s own favourite pursuit that the recom-
mendation often carries but little weight; and yet there is much to be said in
favour of the study of the Rotifera, that cannot be gainsaid. They are to be
found almost everywhere ; they cost nothing; they require neither expensive
lenses nor an elaborate apparatus ; they tempt us to explore the country, and to
take pleasant walks; they are beautiful themselves; and they suggest all kinds
of difficult questions on life and being. Moreover there is happily still a great
store of scientific ignorance concerning them, thus leaving an ample field for
fresh discoveries.

Nor is this all. The study of these animated specks (in which teeth, stomach,
muscles, and even a brain lie hidden in the compass of an invisible mote) irre-
sistibly leads the mind to the contemplation of Him, whose almighty hand is as
visible in an atom of this animated dust, as it is in the myriad sparkles of the
starlit heavens.

Cie rle

CONTENTS

or

eee rE RSS ay VeO UW Moly:

—07,QR0°——

CHAPTER I.

PAGE

INTRODUCTION ° ° ° . ° 5 . . ° 3
CHAPTER II.

HISTORY OF THE LITERATURE CONCERNING THE ROTIFERA . . 16
CHAPTER III.

ON THE CLASSIFICATION OF THE ROTIFERA . 5 5 . 20
CHAPTER IY.

ON THE HAUNTS AND HABITS OF THE ROTIFERA > > . BD)
CHAPTER YV.

RHIZOTA, (PLOSCULARIADA) . : , > . : : - 43
CHAPTER VI.

RHIZOTA, (MELICERTADE) . : 2 : 5 : = » 67
CHAPTER VII.

BDELLOIDA ° . ° . > . ° . . ° 95

PLOIMA, (1L-LoRICcArA) 5 ° ° . . . ° 5 Hil

PE Oa ER As.

Cab AUP a ia a.

DRARARADRAARADAAAN

INTRODUCTION.

a ee ee

Contemplatio Nature pregustus est voluptatis cxlestis, constans animi gaudium,
perfectique ejus solatii initium, summusque felicitatis humane apex. Cum Anima
hujus particeps fuerit, ex gravi quasi sopore excitata, in luce ambulat, sui ipsius
obliviscens, in cielesti, ut ita dicam, terra, inque terrestri ccelo.—%J. Bastur.

Inest in explicatione Nature, insatiabilis quedam e cognoscendis rebus Voluptas,
in qua una, confectis rebus necessariis, vacui negotiis, honeste ac liberaliter possumus
vivere.—CicEro, De Pinibus, lib. iv. cap. 5.

CHAPTER I.
INTRODUCTION.

On the Somersetshire side of the Avon, and not far from Clifton, is a little combe, at the
bottom of which lies an old fish-pond.

Its slopes are covered with plantations of beech and fir, so as to shelter the pond on
three sides, and yet leave it open to the soft south-western breezes, and to the afternoon
sun. At the head of the combe wells up a clear spring, which sends a thread of water,
trickling through a bed of osiers, into the upper end of the pond. A stout stone wall has
been drawn across the combe from side to side, so as to dam up the stream; and there is
a gap in one corner, through which tlie overflow finds its way, in a miniature cascade,
down into the lower plantation.

The pond’s smooth surface is prettily diapered with the green leaves of many a
water-plant, and with the sharp images of three famous beeches growing close to its
edge: but to a naturalist’s eye the old wall is the more charming object. Time has
crumbled away the mortar near the water’s edge, and made a thousand nooks and
crannies ; which, densely clothed with alge, are the haunts of myriads of living creatures.

If we approach the pond by the gamekeeper’s path from the cottage above, we shall
pass through the plantation, and come unseen right on to the corner of the wall ; so
that one quiet step will enable us to see at a glance its whole surface, without disturbing
any living thing that may be there.

Far off at the upper end a water hen is leading her little brood among the willows ;
on the fallen trunk of an old beech, lying half-way across the pond, a vole is sitting
erect, rubbing his right ear; and the splash of a beech husk just at our feet tells of a
squirrel, who is dining somewhere in the leafy crown above us.

But see! the water rat has spied us out, and is making straight for his hole in the
bank, while the ripple above him is the only thing that tells of his silent flight. The
water hen has long ago got under cover, and the squirrel drops no more husks. It is a
true ‘ Silent Pool,’ and without a sign of life.

But if, retaining sense and sight, we could shrink into living atoms and plunge
under the water, of what a world of wonders should we then form part! We should
find this fairy kingdom peopled with the strangest creatures :—creatures that swim with
their hair, that have ruby eyes blazing deep in their necks, with telescopic limbs that
now are withdrawn wholly within their bodies and now stretched out to many times their
own length. Here are some riding at anchor, moored by delicate threads spun out from
their toes; and there are others flashing by in glass armour, bristling with sharp spikes
or ornamented with bosses and flowing curves; while, fastened to a green stem, is an
animal conyolyulus that by some invisible power draws a never-ceasing stream of victims
into its gaping cup, and tears them to death with hooked jaws deep down within its
body.

Close by it, on the same stem, is something that looks like a filmy heart’s-ease. A
curious wheelwork runs round its four outspread petals; and a chain of minute things,
living and dead, is winding in and out of their curves into a gulf at the back of the

B2

4 THE ROTIFERA.

flower. What happens to them there we cannot see ; for round the stem is: raised a tube
of golden-brown balls, all regularly piled on each other. Some creature dashes by, and
like a flash the flower vanishes within its tube.

We sink still lower, and now see on the bottom slow-gliding lumps of jelly that
thrust a shapeless arm out where they will, and, grasping their prey with these chance
limbs, wrap themselves round their food to get a meal; for they creep without feet,
seize without hands, eat without mouths, and digest without stomachs.

Time and space, however, would fail me to tell of all the marvels of the world
beneath the waters. They would sound like the wild fancies of a child’s fairy tale, and
yet they are all literally true; and, moreover, nearly all of them are true of that roti-
ferous world which it is my purpose to describe.

But it will be naturally asked by those of my readers to whom the subject is new,
“ What 7s a Rotiferon ?”’ and no doubt one would say that a book about Rotifera ought to
begin at the beginning, and define precisely what a Rotiferon is.

Precise definition is, however, in such a case, quite out of the question ; for, though it
is easy enough to define the typical form of a natural group of animals, or even to
include in the definition forms that must be placed not far off from the central one, yet
in the ambitious attempt to frame a definition that shall include many families, we find
(as we get farther away from the typical form) that one by one all the positive statements
are disappearing from our definition; and at last we have nothing left but the mere
shell of a proposition, with everything worth the stating struck out of it.

The Rotifera, then, are small aquatic animals varying from 4 to s}, of an inch in
length, and deriving their name from a wheel-like appearance produced by fine circlets
of hairs seated on the front of their heads. A few species are marine; but the great
majority known to us belong to fresh water, and are to be found in ditches, ponds, reser-
voirs, lakes, and slowly running streams, sometimes attached to the leaves and stems of
water plants, sometimes creeping on the algw, sometimes swimming freely through the
water. Although the greater number of the genera resemble each other in the chief
features of their internal organization, so as to form a very natural group of animals, yet
there are several aberrant forms which would render it a difficult matter to include them
all in one precise definition.

This indeed could be done only by introducing so many qualifications and exceptions
to every statement, that the portrait would be rendered too vague for any reader but one
already familiar with the whole subject.

Of the greater number, however, it is enough to say :

(1) That they swim by means of hairs on the front of their heads.

(2) That they possess a simple stomach and intestine; and peculiar jaws.

(8) That they have muscles which are sometimes striated, and which often pass
freely through the cavity of the body.

(4) That they have a well-developed vascular system.

(5) That their nervous system consists of one ganglion, with nerve threads radiating
to their organs of sense.

(6) That they are dicecious; have ova of two kinds; and do not pass through any
distinct metamorphosis.

Though the above six statements are precise enough, and in the main true, yet it
will be as well for those, who are not versed in the subject, to pass them over for the
present, and first to master the structure of some one typical Rotiferon ; as, when this has
been done, the general conception of a Rotiferon will be easily grasped, and the variations
from the type readily followed and understood.

For this purpose I have selected Brachionus rubens, whose figure is given much
magnified in Pl. A, fig. 1. The genus Brachionus is to be met with almost every-
where. It is hardly possible in summer to take a dip of water from a garden-pona, or
to gather the alge from its walls, without bringing up some specimen of the genus.
Brachionus rubens is a fairly common species. It is comparatively a large handsome

INTRODUCTION. 5

animal, very suitable for the purpose of description, and one which bears the tem-
porary captivity of a compressorium remarkably well.

The Female.

Fig. 1, Pl. A, represents the dorsal aspect of the female of this Brachionus, and
fig. 2 the upper part of the ventral aspect. The drawings are from life; but the out-
lines of the various organs have been made unnaturally sharp and distinct, for the sake
of clearness. The dorsal and ventral surfaces may be distinguished from each other in
the great majority of the Rotifera by the following considerations :

First, as to the dorsal surface :

(1) It is arched (fig. 5).

(2) The stomach (fig. 1, s) passes down it ; between it and the ovary (fig. 1, oy).

(8) The cloaca (fig. 1, cl) is on it; in the median line.

(4) There is almost invariably one antenna (fig. 1, a) (ora coalesced pair) on it; placed
anteriorly on the median line.

(5) The eye or eyes (fig. 1, e) are towards the dorsal surface.

(6) In swimming over objects the Rotiferon keeps the dorsal side upwards.

Secondly, as to the ventral surface (fig. 2) :

(1) It is comparatively flat.

(2) The entrance to the mouth lies on it (figs. 2, 5, bf).

(8) The ovary is placed close to it (fig. 2, 5, oy).

In the case of those Rotifera whose dorsal and ventral surfaces have much the
same contour, the aboye considerations present points of difference enough to decide
between the two.!

B. rubens is inclosed in a case or lorica (figs. 8, 4, 5) which is both hard and trans-
parent. The internal structure can be readily seen through it; and, by suffering the
animal to dry on a glass slip, and then dropping on it a solution of caustic potash, the
softer portions of the body may be dissolved away, and the lorica left unharmed.

It will then be seen to be closed above and below, with an opening at each end, like
the shell of a tortoise. From the front opening the head is protruded, and from the
hind the psewdopodiwm or foot (fig. 1, f).

The lorica has a glassy shining surface, and is armed with six short sharp spines in
front, of which the central pair is the longest. Four of them are distinctly on the dorsal
surface; but the outmost pair belongs as it were to both surfaces, being on the edge
where they meet.

The front edge of the ventral surface (the mental edge as it is sometimes termed) °
is hollowed out symmetrically into graceful curves (fig. 4).

The lorica widens from the front backwards, till, at about two-thirds of its length, it
reaches its maximum breadth; and is then rounded off by two ogee curves that are
separated, by a square notch on the dorsal surface, but by a nearly circular one on the
ventral. In consequence, it is often said that the lorica has two blunt spines behind
on the dorsal surface; but this is somewhat misleading, as these so-called spines are
merely the sides of the excavation. Strong ridges from each of the four central front
spines run down about one-third of the dorsal surface (fig. 8), and still longer ridges
mark the ventral surface with sweeping curves (fig. 4).

The median portion of the lorica is by far the deepest, and in it the internal organs
mainly lie. The dorsal surface of the lorica slopes upwards from the head to its line of
greatest width (fig. 5), and then abruptly falls to meet the under surface ; the whole lorica
thinning off there into closely approaching plates, through the excavation in which the foot
can pass. Each side, too, of the median portion of the lorica thins off in a similar
manner ; so that the dorsal and ventral surfaces meet everywhere (except at the head) in
a sharp edge.

1 Cf. Dr. Moxon, Trans. Linn. Soc. vol. xxiv. 1864, p. 455. 2 From mentum, the chin,

6 THE ROTIFERA.

The head is shaped somewhat like a truncated cone, with the larger end forward ;
posteriorly it is studded with several sinall rounded lobes ; while from its anterior surface
rise three fleshy protuberances, crowned with stout vibrating hairs called styles.

Each side of the front of the head, or corona,! is rounded into a nearly circular lobe,
and along the rim of each lobe runs an unbroken row of smaller vibrating hairs, called
cilia, which are continued so as to meet each other on the dorsal surface. It is by
means of this apparatus that Brachionus both swims and procures its food.

As the head is seldom withdrawn into the lorica for more than a moment or two,
and as the cilia begin to play the instant it is protruded, Brachionws would have been
condemned to almost perpetual motion if it had not been for the foot. This organ is
provided at its extremity with two pincer-like processes, or toes (fig. 1, ¢); which, however,
do not pinch, but which can adhere even to glass by means of a viscid secretion that flows
through their tips.

The foot-glands (fig. 1, fy), which secrete this substance, are two club-shaped
organs running down the whole length of the foot. They are to be met with in nearly
all the Rotifera.

The cilia, which are set closely round the edge of the corona, lash the water
with such fury that it is impossible usually to follow the action of any individual cilium;
but, by selecting an animal whose corona is close to the covering glass of the live
box, some spot can often be found where the action of the cilia is checked by their striking
against the glass; and, under these circumstances, it is easy to understand their action.
Hach cilium lashes sharply downwards (like a whip) on the corona, and then rises gradually
into its place again, to repeat the action continuously, so long as the corona is expanded.
As, however, the cilia do not do this simultaneously, but im turn, one after the other, in
very rapid succession, those that can be seen together at any given moment are in every
phase, from complete extension to complete depression; thus giving rise to various wayve-
like illusory appearances, according to the illumination, and also to the plane on which
the objective is brought to focus. One of the most common of these appearances is that
of a toothed wheel, which is so well imitated by the Philodinade, that early observers
thought such wheels existed, and drew them like the escapement-wheel of a watch.?

If a little carmine be mixed. with the water, two beautiful coloured spirals will be
produced by the action of the ciliary wreaths, one on each side of the head leading down
to the buceal funnel. The orifice of the buccal funnel, or, as it will be termed, the buccal
orifice, lies in a niche on the ventral surface; it is fringed by the ciliary wreath, which
here dips down on either side of the corona, and passes round the V-shaped opening of
the buccal funnel (fig. 2, bf) —that is, of the passage leading from the niche to the mastax.
The atoms brought by the ciliary currents pass down the buccal funnel, which itself is
lined with cilia ; and, if uninterrupted, enter the mastaz (figs. 1, 2, mx), a muscular bulb
containing the trophd (fig. 1, ti) or teeth. But it isnot every atom whirled down the buceal
funnel that is suffered to reach the mastax ; for there are two lip-like processes (fig. 2, Up)
rising from the mastax, which can be seen every now and then thrust up and down the
buecal funnel; and which by closing prevent the passage of morsels that are not to
the Rotiferon’s taste. The sudden check, produced by the lips on the inflowing current,
always sweeps out of the buccal funnel whatever the animal desires to reject; and a
constant stream of rejected particles may be seen issuing from the buccal funnel midway
between the spirals caused by the corona.

The Mastax.

The mastaz (figs. 1, 2, ma; fig. 6) is the muscular covering of the jaws or trophi.
It has thick walls, and is slightly three-lobed, each lobe investing one of the three prin-
cipal parts of which the trophi consist. There is an opening in front towards the ven-
tral surface at the bottom of the buccal funnel, whose walls here merge into those of

' A name suggested by Mr. Cubitt in lieu of trochal disk.
* Baker on the Microscope, vol. i. Plate VIII. fig. 6, 1785.

INTRODUCTION. 7

the mastax ; and there is a posterior opening towards the dorsal surface, just above the
cesophagus.

The contained hard parts, or trophi, consist of two hammer-like bodies, the mallet
(fig. 6, ms ; fig. 9), and of a third anvil-piec: called the incws (fig. 6, 7s). Hach malleus
has for its head or wneus (figs. 6, 7, 9, ws) a piece which, when spread out by pressure,
is like acomb with five unequal teeth (fig. 8, ws), but which, under ordinary circumstances,
is much curved, so as to bring the teeth close together.

The handle of each of these hammers is a single stout piece called the manubrium
(figs. 6, 7, 8,9, mm). The anvil or incus roughly resembles a triangular prism, of which
one end (the dorsal one) has been tapered to a point (fig. 10). It is divided into two equal
pieces, the rami (figs. 6, 7, 7s), by a cut from the dorsal to the ventral surface, so as to leave
them just attached to each other at the bottom of the broader end. The two rami rest
there on what looks like a stem, the fulerwm (figs. 6, 7, fm), but which viewed laterally is
seen to be a slender plate (fig. 10, fm).

Muscles, springing from the walls of the mastax, are attached to various parts of the
malleiand rami, and act so as to cause the unci to approach and recede from each other.
But each uncus is fastened to the corresponding ramus ; and, in consequence, as the mallei
recede the rami are opened, and when the mallei approach each other the rami are closed.!

From these arrangements it results that all the food which falls from the buccal
funnel into the mastax, is first torn by the sharp points of the unci and then crushed
between the opposing surfaces of the rami. On passing the rami, the food enters at once
into the cesophagus.

The Gisophagus.

The esophagus (fig. 2, @) is a short tube, with thick walls, connecting the mastax
with the stomach. The thickness of the walls may be readily seen by feeding Brachionus
with carmine, and watching the stream of coloured particles trickle through the @so-
phagus into the stomach. Their course, in a narrow central line, shows clearly the small
dimensions of the passage.

There is always an appearance of water flowing through the cesophagus, even when
the animal has withdrawn its head into the lorica, and when of course the action of the
ciliary wreath has ceased. This appearance seems to be due to minute cilia lining
the esophagus, which by their joint rhythmical action give rise to illusory waves much
larger than any real waves could be. That this explanation is not a mere guess will be
shown farther on in the case of the Floscules.

The Glands.

Seated near the top of the mastax, and on either side of the buecal funnel, are two
clear vesicular organs ; which are possibly salivary glands (fig. 2, sg), and are unusually
large in Brachionus. They consist of two or three lobes on either side, and are best
seen from the ventral side, as the buccal funnel enters the mastax, a little below the
summit, on that side.

There is a pair of glands called the gastric glands (figs. 1, 2, gg) placed at the
anterior end of the stomach, and on either side of it. They exhibit cells with central
nuclei imbedded in a granular substance. Each has a long, wide, nucleated duct
connecting it with the upper end of the stomach. They probably perform the fune-
tion of a rudimentary liver, and possibly cause, by their secretion, the peculiar yellow-
brown colour which is so frequently met with in the stomach. The foot-glands have
already been described in p. 6.

The Stomach and Intestine.
The stomach (figs. 1,2, s) isa simple sack, with thick cellular walls, which are frequently

1 For a full description of the complex action of the trophi see Mr. Gosse’s paper “On the Strue-
ture, Functions, and Homologies of the Manducatory Organs in the class Rotifera,” Phil. Trans. 1856,
p- 419.

8 THE ROTIFERA.

studded with what appear to be bright yellow oil-globules. It is divided by an in-
yagination at its lower third into an upper portion, the true stomach, and a lower
which may be considered to be a short intestine (fig. 1,7). This lower portion frequently
lies transversely to the longer axis of the stomach. Both are thickly ciliated on the
inner surface, but the cilia of the intestine are larger, and more readily seen.

When a portion of digested food has been transferred from the stomach to the in-
testine, it is kept slowly revolving by the cilia, till it is suddenly expelled through the cloaca
(fig. 1, cl). The intestine is connected with the cloaca bya short and very dilatable tube
or rectum (fig. 1, 7), and ends (as has been already said) on the dorsal surface, in the
median line, just at the commencement of the foot. The rectum also is ciliated, so
that the whole of the alimentary tract from the top of the buccal funnel down to the
cloaca, with the exception perhaps of the passage through the mastax, is lined with
cilia.

The Vascular System.

At the right of the intestine (viewed dorsally), and just under the line of the lorica’s
sreatest width, lies the contractile vesicle (fig. 1, cv). This is a delicate bladder which
alternately dilates and contracts, and with some regularity.

The contraction is produced by fine muscular threads, which ramify in its walls,
and cause it to empty its contents through a duct into the cloaca. Its distension is
most probably due to the fluid poured into it by two looped and twisted tubes (fig. 1, Ic),
which may be seen passing to it, one on each side of the body down from the head.

This is, however, a much disputed question, which will be discussed fully in another
place, along with the probable function of the whole apparatus.

The tubes appear to be surrounded with a granular floecose material, which here and
there dilates into irregular masses. Attached to the tubes on each side, at tolerably
regular intervals, are five little tag-like bodies (fig. 1, vt), in which a flickering motion
may be constantly seen, sometimes presenting the appearance of a waving cilium.
There is much difference of opinion about the true structure of these tags—the
vibratile tags, as they are termed—but it is probable that their office is to direct the
perivisceral fluid into the tubes, and along them into the contractile vesicle, whence
it is driven at intervals through the cloaca.

The Muscles.

The dorsal muscles are shown in fig. 3, and the ventral in fig.4. From the posterior
dorsal surface of the head, on each side of the cephalic ganglion, and close to it, a stout
muscle (fig. 8, 1, 1) slopes backward towards the dorsal surface, and is attached by a
broad base to the lining membrane of the lorica. Outside this pair is a second (fig. 8,
2, 2), similarly attached, and running rather obliquely underneath the first pair, but not
quite so stout. A similar pair (fig. 4, 4, 4) is attached to the posterior ventral surface
of the head, and to the lining of the ventral surface of the lorica. The united action of
these three pairs of muscles withdraws the head into the lorica.

When it is so withdrawn, a pair of diverging muscular threads (not given in the
figure) can be seen fixed to the lorica, just below its central notch, with their other
ends fastened to the head. These evidently oppose the action of the three other pairs
(figs. 8, 1, 1, 2,2; 4, 4,4) and help to draw out the head again. They are assisted in
this by a further pair of muscles (also omitted from figs. 3 and 4), each of which
is fastened at one end to the base of one of the outermost anterior spines, and
at the other to a side lobe of the head.

But the principal part in driving out both the head and the foot is borne by transverse
muscles, which are attached to the lorica at the side, and are closely applied through-
out their length to the soft organs of tht body. Their sudden contraction compresses
the perivisceral fluid, and so forces out the retracted head or foot. Nothing could be

INTRODUCTION. 9

more effective than this hydrostatic pressure ; and under it the retracted foot darts out
of the lorica with amazing swiftness.

When the head is protruded, and the cilia are all in full play, Brachionws may often
be seen to move its head, without withdrawing it, first to one side and then to the other,
depressing the side lobes alternately. This action is effected by two pairs of short
muscles (figs. 3, 4,3, 3), one on each side, attached to the lorica at about one-third of its
length from the front, and at their anterior ends inserted into the side lobes.

Just as the muscles attached to the dorsal surface control the action of the head, so
do the majority of those of the ventral surface give its various motions to the foot.
They are six in all. First, two central muscles, closely parallel (fig. 4, 5, 5), and each
divided into two branches at its upper end, run from nearly the middle of the lorica
down to the bottom of the foot, where they appear to be attached each to one of the
toes. Next, two slighter ones (fig. 4, 6, 6), which pass up from the base of the toes,
one on each side of the foot, and then diverge right and left from the central pair to
points on the lorica about half-way between the median line and its edge. Besides
these, there is, attached to the upper end of the foot and on each side of it, a muscle
(fig. 4, 7, 7) which diverges still farther from the median line, and is fastened not far
from the margin, All these six can act together, so as to draw the foot suddenly
within the lorica; while, by contracting some and relaxing others, the animal can
whisk the foot about, or, if the toes be adherent to any substance, can shake its whole
body vigorously from side to side—a favourite action.

The Nervous System and Organs of Sense.

The nervous system is represented by a bean-shaped cephalic ganglion (figs. 11, 1, giz)
seated within the head on its dorsal side. Its substance is marked with what appear to
be the hexagonal boundaries of cells. It is two-lobed posteriorly, and on the niche
between the lobes lies the crimson eye (fig. 11, e).

The pigment is distinctly curved round both sides of the niche so as to lie on each
lobe, and to give rise to the notion that the eye may really represent a pair fused into
one. I have not detected in this Rotiferon the clear spherical lens which is so plainly
visible in some of the others.!. Attached to the upper portion of the cephalic ganglion
on the dorsal side is a conical and very flexible tube (fig. 1, a), whose broad base rests
on the ganglion, and whose free end passes through the sinus in the lorica between the
two longest spines. This is the dorsal antenna. A bulb armed with motionless sete
completely closes the orifice of the tube; and is so attached to its rim, that when this
bulb is withdrawn by the contraction of a muscular thread fastened to its base, the
tube is drawn down also by being infolded like the finger of a glove (fig. 15).

There are two other setigerous bodies, close to the dorsal surface of the lorica,
and with the sete protruding through the surface. They are near the margin on each
side, a little above the line of greatest breadth (fig. 1, a’). They are rocket-shaped struc-
tures, the cylindrical heads carrying on their blunt, rounded, outer ends, radiating sete ;
and giving off, from their inner and pointed ends, cords which can be traced but a little
way below the surface,

But the list of the tactile organs of Brachionus is not yet exhausted. From the two
spaces on the dorsal side of the corona lying between the three large setigerous promi-
nences (fig. 1, sp) rise two papille, each bearing a long and very flexible style (fig. 1, ts).
A similar style (fig. 2, ¢’s’) is placed on the ventral side, just within the rim of each ciliary
circlet ; and another pair on the top of the central promimence. The whole six are
very mobile ; and, from the way in which they seem to be used to explore in all direc-
tions, there is little doubt that they are organs of touch.

1 As in Pedalion, Conochilus, &c.

10 THE ROTIFERA.

The Reproductive System.

The reproductive system of the female is only too conspicuous ; as the presence of a
large ovary (figs. 1, 2, oy), and of one or two opaque ova in different stages of growth,
frequently obscures the sight of the other organs.

The ovary is studded with large and rather irregularly shaped germs (figs. 1, 2,9); and
the ova (fig. 1, om), so long as they are within the body, are dark, granular, and homo-
geneous. The ovary opens doubtless by an oviduct into the cloaca, but this I have not been
able to see. This is the arrangement that exists in other cases wherever I have seen
the oviduct. The mature ovum is expelled very quickly ; and the egg often remains
attached to the animal by a thread till the young escapes by rupturing the shell (if it
may be so termed) in which it is inclosed. If, however, a Brachionus, with two or
three eggs attached, be held in the compressorium, it will frequently free itself by
pushing with its foot against the eggs, and so breaking the threads.

The Egg.

Of the eggs and their development it is unnecessary here to say more than that
B. rubens has two kinds of female eggs, nearly of the same size ; of which the one has a
smooth, transparent, membranous covering or shell, while the other has a thick opaque
shell, ornamented with hemispherical knobs. The former is the ordinary ‘‘ summer ”’
ege, and the latter the so-called “lasting,” ‘‘ winter,” or ‘‘ephippial” ! egg. In shape,
too, the ephippial egg differs from the ordimary female one. It is much bigger at one end
than the other, and at the smaller end there is a projecting neck and cover (fig. 16).

The male eggs are smooth and semi-transparent like the ordinary female egg ; but
are somewhat rounder in shape, and barely half the size. They occur, too, in larger
clusters; for while it is usual to see only two or three smooth female eggs, or one
ephippial egg, attached to the mother, no fewer than eight or ten male eggs may be seen
carried about together.

The Male.

The young female Brachionws when hatched resembles its mother; but the young
male is a widely different animal (figs. 18, 14). It is about one-third of the length of
the adult female’s lorica, and it has neither lorica, mastax, jaws, nor stomach.

The head bears a simple circle of long cilia, and there is a red eye on a cephalic gan-
glion placed just as it is in the female. The vascular system, with its tortuous
canals, yvibratile tags, and contractile vesicle, is also present ; and the foot is furnished
with the usual pair of glands; but of a nutritive system there is not the slightest
vestige.

Nearly half the body is occupied by a great sperm-sack (figs. 18, 14, ss), in which
under favourable circumstances the spermatozoa themselves may be seen in motion.
The sperm-sack ends in a short protrusile tube, the penis (figs. 18, 14, p), ciliated at the
end, and placed just above the foot.

In the larger and more transparent males of other genera—notably in that of
Asplanchna Ebbesbornii—there are special muscles for drawing back the protruded
penis ; and, though I have failed to see these in the male of B. rubens, it probably
possesses a similar structure.

This strangely unfurnished creature leads a brief life of restless energy, now darting
from place to place, so swiftly that the eye can scarcely follow it, and now whirling
round as if anchored by its curved foot and penis.

It often circles round the female, attaching itself now here, now there, and forcing its
companion to waltz round and round with it, from the top of the phial to the bottom,
With animals so active and so small it is difficult to be certain of having seen actual

1 So named by Prof. Huxley from the resemblance to the lasting-eggs of the Daphniw. These
latter were called “ ephippial’’ by Miiller from their shape, which is that of an ephippiwm, or saddle.

INTRODUCTION. 11

coitus, but Mr. Gosse had this good fortune in the case of a closely allied species,
B. pala. He says:

‘*T collected about a dozen females, half-grown and adult, and placed with them two
lively males that had been hatched during the night. Idirected my attention principally
to one of these, as I could not watch them both. It soon came near one of the females,
when it seemed to become animated by a sort of frenzy; describing with excessive
rapidity a cirele, of which its head formed the circumference and its foot the centre. The
extremities were incuryed in the direction of its circular movement. After a while it
left off, and began to play about the body of a female, moving over and round the lorica,
while she whisked about the foot, as if to lay hold of him; at leneth she drew in her
foot, and that of the male appeared to adhere to it; and I distinctly saw the thick penis
presented to the cloaca, and for a moment inserted about half its own length; then it
was instantly drawn out, and the male began his frenzied gyrations again.” !

It is obvious, even from the brief account here given, that several highly interesting
questions arise concerning the reproductive system of the Rotifera. For instance, in what
respects, besides outward form and covering, do the ephippial eggs differ from the smooth
female eges ? and what leads to their production ?

What part, if any, does the male play in these differences? and how is it that one
female produces none but male, while another has none but female eggs ?

Again, why are the males of so strange a structure ? and why do they appear only for
a short time during the year? and is their appearance due to external causes, or are
they the inevitable completion of a cycle of reproductive changes ?

Unfortunately it is much easier to ask these questions than to answer them. The
observations that have been made on these points are but scanty; and, to some extent,
contradictory; and the difficulties in the way of persistent investigation are by no means
shght.

1“ On the Diwcious Character of the Rotifera.’”’ Phil. Trans. 1857, | 19.

(Gielval Mh ish dei Ele
THES RISTORY OF THE, TITERATURE: CONCERNING
THE ROTIFERA.

Multum egerunt, qui ante nos fuerunt, sed non peregerunt. Multum adhue
restat operis, multumque restabit; nec ulli, nato post mille secula, precludetur
oceasio aliquid adhue adjiciendi.—Seneca, Hpist. lxiv.

Czxterum nullius in verba jurans, aliorum inventa consarcinare haud institui;
que ipse quiesivi, reperi, debitaque attentione et patientia repetitis vicibus, diver-
soque tempore annorum serie observavi, propono.—O. F. MtLurr, Verm. Terrest.
et Flu, pref.

CHAPTER De

THE HISTORY OF THE LITERATURE CONCERNING THE
ROTIFERA.

Ir is nearly 200 years since Mr. JOHN HARRIS, F-.R.S., Rector of Winchelsea, pub-
lished in the ‘‘ Philosophical Transactions”! the following ‘‘ Microscopical Observations”
on a drop of some rain water which ‘‘ had stood in a gallipot in his window” for about
two months :

“‘T saw here an animal like a large maggot, which could contract itself up into a
spherical figure, and then stretch itself out again; the end of its tail appeared with a
forceps like that of an earwig; I could plainly see it open and shut its mouth. from
whence air-bubbles would be frequently discharged. Of them I could number about
four or five, and they seemed to be busy with their mouths as if in feeding.”

This description is but vague; and yet it is very probable that the animal which the
rector found in his gallipot was a Rotifer: and if so, this is the earliest notice that we
have of the class.

A few years later, in 1703, LEUWENHOEK published, in the same ‘‘ Transactions,”’?
an account of some animalcules, living in sheaths, that he had found at Delft, on sreen
weed brought by the flooding of the Maes from Delft Haven. These little creatures were
almost certainly Limnias ceratophylli. Leuwenhoek gives figures of one, and notices
its bearing ‘‘ two wheels thick set with teeth as the wheel of a watch.” Ina later paper ®
in the ‘‘ Philosophical Transactions’ he gives a much better account of Limnias, with
greatly improved figures. He states that when the two wheels are viewed frontally they
are seen to be continuous and to form but one; and he adds a figure (Pl. B, 4) of the
corona so seen, and notices that the ciliary waves run right round the whole wreath
in the same direction.

Leuwenhoek next describes an animal ‘‘ that has a receptacle or little house com-
posed of round bubbles,” and furnished with “‘ surprising wheelwork ”’ of four parts, three
of which only were shown in his figure, ‘‘ the fourth being almost hid from sight.’ One
glance at the figure of the animal (PI. B, 1), and at its corona (Pl. B, 2), shows us that
he has had Melicerta ringens under his microscope.

His next paper* on the same Rotiferon is pleasant reading ; for it vividly recalls the
shock of delighted surprise with which every naturalist first enters into the enchanted
world beneath the waters.

“T took notice,” he says, ‘‘ of the surprising figure of an animalculum, fixed in a little
scabbard or sheath, fastened to some of the small green weeds found in ditches of water.
And, as often as I viewed these animaleula and showed them to others, we could not
satisfy ourselves with looking on such surprising objects; and the more because we
could not conceive how so strange a motion, as they all had, could be performed; as
also what should be the use of such a motion.” Leuwenhoek also relates how Meli-
certa makes its tube pellet by pellet; and this is his account of it. ‘I viewed one of
these animalcula a good while together; and observed, several times, one after another,
that when the animalculum thrusts its body out of the sheath or case, and that the

1 Phil. Trans. vol. xix. 1696. 2 Phil. Trans. No. 283, 1703.
3 Phil. Trans. No. 295, 1705. 4 Phil. Trans. No. 337, vol. xxviii. 1713.

16 THE ROTIFERA.

wheel-like or indented particles moved in a circle, at the same time out of a clear and
transparent place a little round particle appeared, which, without nicely viewing, could
hardly be perceived; which particle growing larger, moved with great swiftness as it
were about its own axis, and continued without any alteration in its place, till the
animalculum had drawn part of its body back into its sheath ; in doing which it placed
the said round particle on the edge of its sheath, which thus became augmented with a
round globule; and whereas the animaleulum had placed the said globule on the east
part of its sheath, another time it fixed it on the south or north side; by which means
the sheath was regularly increased on all sides.”

Of course this is but a rough sketch of the machinery and actions of the famous tube-
maker; but it is a vigorous one, and true to the life as far as it goes.

With equal truth and vigour does Leuwenhoek describe, in the same paper, the
transformations of Philodina roseola ;—that creature, whose powers of lying dormant for
rotiferous ages, and of then coming to life again, have made it as famous as the “Seven
Sleepers.”

To anyone with a sense of humour it must be delightful to read the following para-
graphs of Leuwenhoek’s paper ; and then to reflect how his discoveries have been re-
peatedly re-discovered; and how again and again they have been challenged, con-
firmed, forgotten, and once more discovered. In fact, the Philodine has been the
cause of a dispute which has all the marvellous properties of the Rotiferon itself. For it
periodically goes to sleep and revives again, just as P. roseola does; but with a difference.
The Rotiferon, when it awakes after its long sleep, takes up its life at the point where it
left it off; and ultimately “ gives up its murmuring breath ” after an existence of three or
four years; but the dispute concerning it invariably begins again both de novo and de
ovo; and having already lasted, with periodical intermissions, for nearly 200 years,
evidently bids fair to last for 200 years more ; as it has only a short time ago awakened
once more, as fresh and as vigorous as ever, and found its way into our daily papers.

“ T discovered,” says Leuwenhoek, “several animalcula that protruded two wheels out
of the fore-part of their body as they swim, or go on the sides of the glass. . . . This sort
I found, in great numbers, in the gutter water which had stagnated some days in the small
pits or cavities of the lead. . . . In October 1702, I caused the dirt of the gutters, when
quite dry, to be sathered together, and taking a small quantity of it, I put it into a paper
on my desk; since which time I have often taken a little of it, and poured on it boiled
water after it had stood still till it was cold, that I might obviate any objection that
should be made, as if there were living creatures in that water. These animalcula, when
the water runs off or dries away, contract their bodies into a globular or oval figure. . . .
In the month of September I put a great many of the last-mentioned animalcula into a
wide glass tube, which presently placed themselves on the sides of the glass ; whereupon,
pouring off the water, I then observed that several of the animalcula, to the number of
eighteen or nineteen, lay by each other in a space of coarse sand; all of which, when
there remained no more water, closed themselves up ina globular figure. Some of these
animalcula were so strongly dried up that one could see the wrinkles in them, and they were
of a reddish colour; a few others were so transparent, as if they had been little glass
balls, that, if you held them up between your eye and the light, you might move your
fingers behind them, and see the motion through their bodies. After these animalcula
had lain thus dried up a day or two, in an oval or globular form, I poured some water
into the glass tube ; whereupon they presently sank to the bottom, and after the space of
about half an hour began to open and extend their bodies, and, getting clear of the glass,
to swim about the water. . . . In the month of October, before the dirt of the leaden
gutter was quite dried up, I took a handful of it, and laid it on a glazed earthen dish in
order to preserve it. . . . Upwards of twenty-one months after, I took some of this dry
stuff and infused it, both in cold water that had been boiled, and in rain water newly
fallen ; whereupon the animals began to show themselves in great numbers.”

The only points of this much yexed question that Leuwenhoek passes over are:

HISTORY OF LITERATURE CONCERNING THE ROTIFERA. 17

(i) how the Rotiferon, when drawn up into a ball, resists the persistent baking of a summer’s
sun on the housetop, or the long drought of twenty-one months on the naturalist’s desk,
without parting with its own internal moisture ; and (ii) why only eighteen or nineteen
of his Rotifera (those near the coarse sand) succeeded in rolling themselves up and sur-
viving, while the rest perished.!

The investigations thus worthily begun by Leuwenhoek were carried on with much
spirit by many other observers ; and, during the hundred and thirty-five years that
elapsed before the publication of Ehrenberg’s famous work, ‘‘ Die Infusionsthierchen,”
no fewer than sixty of Khrenberg’s species, contained in thirty of his genera, were
entered on the list of known Rotifera.

I have arranged the more striking forms of these in the following table, which
classifies them under the heads of some of the families into which I have divided the
Rotifera ;? and I have added the names and dates of their discoverers ; it will be thus
seen how wide a ground had been covered by the early naturalists, since more than
half the families have representatives in the table.

A List of some of the Rotifera discovered before 1838.

{ Stephanoceros Eichhornii Hichhorn, 1761

LAE * (Ploseularia ornata Eichhorn, 1767
[EEE ringens . Leuwenhoek, 1703
Rear eaaeis Limnias ceratophylli Leuwenhoek, 1703
. 7 : | Eecinulaia socialis 5 Brady, 1755
Megalotrocha alboflavicans . Rosel, 1755
Peoeinn i Rotifer macrurus . Baker, 1753
* |Philodina roseola . Leuwenhoek, 1702
Hypatinap® Hydatina senta Miiller, 1773
SyncH# TAD Syncheta Baltica . Baster, 1759
NoromMAtTaD® . Notommata tigris . Miiller, 1786
TRIARTHRADE . Triarthra longiseta Eichhorn, 1775
(Brachionns pala Joblot, 1718
BRAcHIONIDE . | Brachionus urceolaris . Hill, 1751
lees striata Miiller, 1776
PTERODINADE . Pterodina patina . Hichhorn, 1775
Evcuianis® Euchlanis dilatata Eichhorn, 1775
RarrvuLipz . Mastigocerca carinata . Miiller, 1786
DeNOGHARGD Dinocharis pocillum Miiller, 1776
. * \Stephanops lamellaris . Miiller, 1786

It will be seen that the names of Hichhorn and Miiller occur much more frequently
than that of any other observer in this list, and their works on the Rotifera deserve,
IT think, a special notice.

JOHANN CONRAD EICHHORN was the pastor of St. Catharine’s church at Danzig,
and his book on the “‘ Natural History of the Smallest Aquatic Animals” * was published
in 1781. Though small, it is a most interesting work. He gives figures and descriptions of
about a dozen Rotifera that can be identified, including Stephanoceros, Floscularia,
Melicerta, Triarthra, Dinocharis, Actinurus, Euchlanis, and Pterodina ; and of most of
his species he was the discoverer.

His enthusiasm is delightful. ‘I have devoted myself,” he says, ‘‘ to this invisible
world, which yields itself to our ken only under the magnifying glass; and I have, for
eleven years, spent my leisure moments on it, so far as my professional duties would
permit, in order to know God in His smallest and invisible works; and I have found
Him very great therein. Not the great works only, those vast heavenly bodies—

1 The question will be found fully discussed farther on in the general account of the family
Philodinade.

2 See chap. III. On the Classification of the Rotifera.

8 Beitrige zur Naturgeschichte der kleinsten Wasserthiere.

18 THE ROTIFERA.

not those huge animals, on earth as well as in sea, who can scarcely drag the
weight of their frames—not these alone declare the glory of the Almighty. No! the
smallest also show, just as distinctly, the perfections of their Creator. Yea! one may
say, these even more than those! A great church clock is certainly a wonderful machine,
but a pocket watch—a watch in a ring—is yet more so, and conduces to the greater fame
and glory of its maker.”

His description of his chief discovery, that of his Crown Polyp (Stephanoceros
Bichhornii) is very amusing. ‘I found,” he says, ‘“ this extraordinary and marvellously
formed animal first in 1761, on July 20, on a water plant, which had been standing some
weeks in water. Isaw that there was something on the plant which was quite unknown
tome. I moved the glass, in order to see if it was something alive, and if it would draw
itself together, which happened, to my delight ; therefore I examined it through a lens,
but it appeared to me, through this, just like an orange flower which was not yet closed,
but which now drew itself together, and now outspread itself. All this stirred up in me
a great desire to see this new animal under the glass, but that required skill to get it
out, as the glass vessel in which it was, was nearly an ell high, and this animal was right
at the bottom. I tried first with the quill of a feather to bring it to the top, but it was
continually lost to the eye by shutting itself up. At last I succeeded with a little wire
hook in drawing out the plant on which it obviously was, and as soon as I could reach
it with the scissors I snipped off a tiny stem, and that brought me out the whole animal
unharmed. I placed it at once under the magnifying glass, and saw this matchless
creature as it is shown in the engraving.” ! What a pleasant picture this is of the
grave pastor fishing away with a quill pen to fetch up Stephanoceros from the bottom of
a glass beaker a yard and a quarter high !

About the same time as Hichhorn, flourished the great Danish naturalist, OTHO
FREDERIC MULLER. He was an excellent botanist and zoologist, and published
works on many subjects. He wrote on the Flora and Fauna of Denmark, on Fungi, on the
Hydrachne, and on Fresh-water and Marine Worms; but his chief delight was in the
Infusoria, and his posthumous work, ‘‘ Animalcula Infusoria Fluviatilia et Marina, &e.”
1786, was the first that brought this new kingdom to the knowledge of the naturalist.

The ‘‘ Animalcula Infusoria’”’ contains the descriptions and figures of about fifty
Rotifera, among which are Lacinularia, Hydatina, Scaridium, Triarthra, Brachionus,
Anurea, Pterodina, Euchlanis, Dinocharis, Stephanops, and Mastigocerca. More than
half of Miiller’s species were new when published; and his figures, taken from life, are
beautifully drawn on copper by himself. Of course there is a great lack of detail in the
drawings of the internal structure of the animals, but they are an immense advance on
those of Hichhorn, the outlines being usually both spirited and faithful.

Miiller’s text, too, is as good as his figures. It is the work not only of a naturalist,
but of a thoughtful and learned man ; and both the ‘‘ Animaleula Infusoria ’’ and his pre-
vious work, ‘‘ Vermium Terrestrium et Fluyiatilium,” abound with admirable and striking
passages. In the latter, he thus begins his dissertation on the Infusoria: ‘* The world
of the invisible, a world shut to our ancestors, was first entered about a hundred years
ago. It breeds monsters of unheard-of form and manner of life, it abounds in miracles
as much as do the remote Indies ; but is explored with lesser peril, for it lies everywhere
at our very feet, and is not sought out for gold.

“Hach was explored with great slaughter of its inhabitants ; the one often resisted
by wasting the lives of its aggressors, the other had no defence but patience.

“This we owe to the needle, which joined two hemispheres together ; that to the
lens, which images alike the solar spots and the infusoria, the widest apart of all things.

“Tn this interval what indeed is great, what little? Man: for he thinks and suffers.”’

L. JOBLOT styles himself, ‘‘ Professeur Royal en Mathématiques, de l’Académie Royale
de Peinture et Sculpture, demeurant sur le Quay de l’Horloge du Palais, au gros Raisin.”’

1 See Pl. B, fig. 14.

HISTORY OF LITERATURE CONCERNING THE ROTIFERA. 19

His book, published in 1718, consists of two parts. In the first he describes various
forms of microscope, and the best way of using them; in the second he details, from his
diary, the results of a series of experiments made with infusions of various plants and
substances. The list of his infusions is long and curious. He tried pepper, roses,
rhubarb and senna, maize, violets, mushrooms, hay, raspberry stalks, celery, knapweed,
fennel, straw, marigolds, melons, tea, oak bark, &c. &e., and even found an animalcule
that,—

for saving charges,
A peeled sliced onion eats, and tipples verjuice.

He scoffs at the notion that living animals could be produced by the putrefaction of any-
thing, and is confident that the infusion of each substance produces its own peculiar
animals. He supposes that eggs are laid on these substances ‘‘by a countless
number of very little animals that fly or swim in the air close to the ground,” and
who “ let fall their eggs and little ones as they course backwards and forwards in the
air,” particularly in the spots where they were stopped by the vapours escaping from their
favourite plants.

He was the first to discover the genus Brachionus (B. pala and B. amphiceros), and
he found in his infusions various species of the genus Rotifer (probably R. vulgaris and
Ri. citrinus) as well as, possibly, a Lepadella and a Monostyla.

His figures are grotesque enough ; and he damaged his reputation asa sober naturalist
by sketching a six-legged creature with ‘tout le dessus de son corps couvert d’un beau
masque bien formé, de figure humaine, parfaitement bien fait.” A fierce moustachioed
face it is, and, as Joblot adds, ‘‘ couronné d’une coéffure singuliére.” His names for the
animals are as odd as his figures: he has ‘“ top-knots,” ‘‘ bagpipes,”’ ‘‘ dandies,” ‘ tor-
toises,” “‘ kidneys,’’ and even ‘‘ crowned and bearded pomegranates "—the last strange
title being given to his new discoveries, the Brachioni.

In spite of all these absurdities his written descriptions are often vivid and accurate,
and he is a shrewd observer. or instance, he notices how cleverly the Rotifera swim
without jostling each other; and he concludes that ‘‘ though we cannot see them, they
must have eyes, and those very good ones.” He describes the restless movement of
Brachionus swaying from side to side as it thrusts about its long foot, and observes that
‘‘there are some females who carry only one egg, some that carry two, and some as many
as six, which, however, is not common; and when there are so many eggs they are
smaller in size than they are when they are fewer.”

It is thus clear, both from his description and his figure, that this first discoverer of
Brachionus pala had already lighted on a female carrying a cluster of male eggs. Again,
he discerns the difference, in size and colour, between Rotifer vulgaris and Lf. citrinus ;
and describes their leech-like movements, their telescopic joints, and their constantly
moving jaws. I need hardly add that he considers the latter to be the heart.

His comments on his discoveries are as characteristic as his figures and theories.
We have seen the Danish naturalist exulting in the human intellect which, armed with
one simple weapon, attacks alike the distant planets and the invisible infusoria ; and find-
ing even greater reason for his pride in the very weakness and ills that flesh is heir to.
The Prussian pastor, too, is as enthusiastic after eleven years’ study as he was when
he first began; and, as if he would add another verse to the Benedicite, cries to all the
creatures of the invisible world, ‘‘ Bless ye the Lord; praise Him and magnify Him for
ever.”’ And Professor Joblot is also enthusiastic, but his strain is pitched in a different
key. He says of one of his infusions that ‘it gives rise to a most delightful spectacle,
so curious to see and watch that Ido not think that the diversion of the play, of the
opera with all its magnificence, of rope-dancing, tumbling, or of the animal-combats
which we see in this superb city, ought to be preferred before them.”

It would be unfair to M. Joblot not to add that he is capable of better things, as the
following extract shows :

“There is nothing despicable in nature ; and all the works of God are worthy of our
c2

20 THE ROTIFERA.

respect and admiration, especially if we take heed to the simplicity of the means by
which God has made and preserved them. The smallest gnats are as perfect as the
hugest animals, the proportions of their limbs are equally just, and it seems as if God
had even wished to give them more ornaments than He has to the greater creatures, in
order to make up to them for the smallness of their bodies. They have crowns, tufts,
and other adornments on their heads, which surpass all that female luxury has invented ;
and we may say that those who have looked only with unaided eyes have seen nothing
so beautiful, so fitting, nor even so magnificent, in the palaces of the greatest princes, as
that which the microscope shows on the head and body of a simple fly.”

About forty years after Joblot, HENRY BAKER, F'.R.S., published a somewhat
similar work. The first volume, ‘‘ The Microscope made Easy,” treats of the instrument
itself ; while the second volume, ‘‘ Employment for the Microscope,” describes the various
things that may be seen with it.

In the second volume he gives an elaborate account, with figures, of what I believe
to be Philodina roseola; as well as descriptions and drawings of Lotifer macrurus,
Brachionus pala, B. urceolaris, B. Bakeri, and probably also of Huchlanis triquetra ;
and of these six species the second and last had not been described before.

His drawings are vastly superior to those of Joblot, especially his figures of the
Brachioni. He notices and introduces into his figure the long vibrating styles which
crown the head of B. pala, as well as its winter eggs. He failed, indeed, to understand
the lorica of Huchlanis ; but that isno wonder, for he has had many to bear him company.

It is unnecessary for me to say more of a book that is still within everyone’s reach ;
but there is one admirable passage in his preface that I must give myself the pleasure of
quoting.

“That man is certainly the happiest who is able to find out the greatest number of
reasonable and useful amusements, easily attainable and within his power; and, if so,
he that is delighted with the works of nature, and makes them his study, must un-
doubtedly be happy; since every animal, flower, fruit, or insect, nay, almost every
particle of matter, affords him an entertainment. Such a man never can feel his time
hang heavy on his hands, or be weary of himself, for want of knowing how to employ
his thoughts; each garden or field is to him a cabinet of curiosities, every one of which
he longs to examine fully ; and he considers the whole universe asa magazine of wonders,
which infinite ages are scarce sufficient to contemplate and admire enough.”

In Plate B, I have given copies of some of the old figures drawn by these authors, and
if the reader will compare them with EHRENBERG’s drawings of the same animals, he
will seé at a glance why the Prussian naturalist’s work ' swallowed up as it were the very
memory of all his predecessors. Instead of feeble, inaccurate drawings, in which the
internal structure was represented by mere blots and patches, Ehrenberg gaye excellently
drawn figures full of accurate details ; and at the same time described the animals them-
selves with wonderful exactness, considering the very great number that he studied
unaided.

Nor was this all: he had such a grasp of the whole subject, such a minute personal
knowledge of the living animals themselves, that he invented a system of classification
which has held its own for nearly fifty years.

In addition to its other merits, Ehrenberg’s splendid work added more than a hundred
new species to those already known, containing among them such remarkable forms as
Conochilus volvox, Notommata clavulata, N. copeus, N. centrura, Diglena grandis,
Polyarthra platyptera, Noteus quadricornis, Microcodon clavus, Gicistes erystallinus, &e.

Three years after the publication of ‘‘ Die Infusionsthierchen,’”” DUJARDIN published
his ‘‘ Infusoires’’ as one of the volumes of the Histoire Naturelle des Zoophytes in the
‘Suites 4 Buffon.” The last part of this volume, being one-sixth of the whole, is devoted
to the ‘‘ Systolides ”’ or Rotifera. His book is mainly critical, and, so far as I can find, con-
tains little on the Rotifera that was new, except his observations on Albertia and Lindia.

1 Die Infusionsthierchen ; Leipzig, 1838.

HISTORY OF LITERATURE CONCERNING THE ROTIFERA. 21

His criticisms are shrewd and often just; he points out that Ehrenberg’s respiratory
tube is probably an antenna; suggests that the convoluted tubes, flickering tags, and
contractile vesicle of the vascular system have a respiratory function; calls atten-
tion to the varying forms of the mastax and trophi as good characters for classification ;
and conjectures that the perivisceral fluid is the true analogue of the blood.

On the other hand, he could not see Floscularia’s tube; could not make out the
striated muscles in any Rotiferon, even in Pterodina patina, of which he gives a figure ;
could see indeed no difference between the muscles and the nerves ; doubted the exist-
ence, as specialised structure, of either the one or the other; and from want of personal
acquaintance with them, affirmed the identity of many of Ehrenberg’s species, which
are undoubtedly distinct.

But although he has small claim to be considered either an original or an accurate
observer of the Rotifera, he made one happy hit in his attempted classification, which
will be detailed elsewhere.

Since Dujardin’s time the more noteworthy essays that have been published on
various portions of our present subject are by Mr. P. H. Gosse, F.R.S.; Dr. F. Leydig ;
Professor T. H. Huxley; Herr C. Vogt; Dr. F. Cohn; Dr. W. Moxon, F.L.S.;
Dr. W. Salensky; Dr. 8. Bartsch; and Herr Karl Eckstein.

Mr. GOSSE, in his paper, ‘On the Anatomy of Notommata aurita,”! described with
minuteness the organization of this common species, so that the essay became, as it
were, a key to the structure of the majority of free-swimming Rotifers. His next treatise,
“On the Structure, Functions, and Homologies of the Manducatory Organs in the Class
Rotifera,”’ ? is illustrated witha great many drawings of the mastax and trophi of various
species ; and discusses the changes that they undergo, in passing from the typical to the
most aberrant forms. It is in this treatise that Mr. Gosse contends that the dental
organs of the Rotifera are true mandibule and maxille; and that the mastax is a mouth ;
and assigns to the Class a position among the Articulata. In a subsequent paper, ‘‘ On
the Dicecious Character of the Rotifera,” ? Mr. Gosse extended this character from a single
genus, Asplanchna, to five others; and trebled the number of the known diwcious species.
Some years later, Mr. Gosse began, in ‘‘ Contributions to the History of the Rotifera,”’ 4
a general account of the whole class, arranged according to a classification of his own,
and continued it so far as the Flosculariade, Melicertade, and Notommatina, illus-
trating each family with descriptions and figures of certain selected species. This work,
however, owing to the cessation of the periodical, was never completed.

Dr. F. LEYDIG, in “ Ueber den Bau und die systematische Stellung der Riiderthiere,”’*
after a full description, accompanied with figures, of many species, three of which are
new, proceeds to deal with the structure of the Rotifera as a class, and to arrange them
in a system of his own. He further discusses their true position in the animal kingdom,
and assigns them a place among the Crustacea.

Professor HUXLEY, in his paper, ‘‘ On Lacinularia socialis ; a Contribution to the
Anatomy and Physiology of the Rotifera,’’® takes this Rotiferon as his text, and, while
minutely describing its structure, discusses various questions concerning that of the
whole class. He enters into the general relations of the Rotifera to other animals, and
arrives at the conclusion that they are permanent forms of Kchinoderm larve.

Herr C. VOGT, in his treatise, ‘‘ Hinige Worte tiber die systematische Stellung der
Riiderthierchen,”’ 7 combats Leydig’s reasonings and conclusion on the position of the
Rotifera, and affirms that they must be classed among the Vermes.

In Dr. F. COHN’s essay, ‘‘ Ueber die Fortpflanzung der Riderthiere,’’* the males
and females of three species are minutely described, especially with reference to their
reproductive organs; and the general question of the reproductive system of the whole
class is also discussed.

Dr. W. MOXON’s ‘Notes on some Points in the Anatomy of the Rotatoria”’® cal]

1 Trans. Micr. Soc. 1852. 2 Phil. Trans. 1856. 8 Phil. Trans. 1857.

4 Popular Sci. Rev. 1862 and 1863. 5 Leipzig, 1854. 6 Trans. Micr. Soc. 1853.
7 Sieb. u. Koll. Zeits. 1855. 8 Sieb. u. Koll. Zeits. 1856. ® Trans. Linn. Soc. 1864.

22 THE ROTIFERA.

attention to the right use of the terms ‘dorsal ”’ and ‘‘ ventral” as applied to the Rotifera ;
to the existence, in many species, of three antenne, holding definite positions with
respect to the dorsal and ventral surfaces; to the true nature of the entrance to the
crop of Floscularia; and to the structure and function of the vibratile tags.

Dr. W. SALENSKY’s paper, ‘“ Beitriige zur Entwicklungsgeschichte der Brachionus
urceolaris,”’! traces the gradual changes in the ovum, from its first division into two
unequal spheres, through its complete segmentation, to the formation of the germinal
layers, and the evolution of the various organs of the completed embryo. Although
the paper deals with only a single species, it is our principal contribution to the Km-
bryology of the Rotifera.

Dr. 8. BARTSCH, in ‘“ Rotatoria Hungarie,”’ 1877, and Herr KARL ECKSTEIN,
in “Die Rotatorien der Umgegend von Giessen,’ ? have published treatises containing
descriptions and figures of local Rotifera (forty in Hungary and fifty at Giessen), in-
cluding two or three new species; as well as new classifications of the whole class
ROTIFERA.

Of Dr. BARTSCH’s work I can say but little, as it is written unfortunately im Hun-
garian. His figures, though somewhat archaic, are well worth the studying ; and he gives
drawings and descriptions (happily this time in Latin) of six new species, of which two
had been recorded in England some years before.

Herr ECKSTEIN also gives many interesting details of his local species, of which
two are new; and adds a general discussion of the structure, development, affinities, and
classification of the whole class. His treatise also contains useful lists of synonyms,
as well as a good bibliography of the subject.

The last edition (1861) of PRITCHARD’s ‘ History of Infusoria,”’ by Dr. Arlidge and
others, is a work differing in character from any of the above. About one-sixth of it is
devoted to the Rotifera, and contains descriptions of the whole of the then known species,
illustrated by a great many figures. Both the descriptions and the figures have been mainly
taken from Ehrenberg’s work, which is closely followed throughout ; but they have been
supplemented by others taken from the various treatises mentioned above.

As a compilation, it is not only the best, but almost the only, English work on the
subject. It contains, moreover, an admirable and exhaustive treatise on ‘‘ The General
History of the Rotifera”’ as a class, dealing minutely with their structure, reproduction,
development, systematic position, and classification.

This original and most valuable essay may be said to be indispensable to all students
of the Rotifera, bringing together, as it does, into one point of view, the opinions of all
the best observers, on the many vexed questions that these little creatures have given
rise to, not only as to their organization and development, but as to their relations to
the rest of the animal kingdom.

A full list of works on the Rotifera, includmg numerous papers that have been
published in various scientific periodicals, will be found at the end of this work.

1 Sieb. u. Koll. Zeits. 1872. 2 Sieb. wu. Koll. Zeits. 1883.

Cae ACE iy iy a Te,

ONS THES CLASSIRICATION OF THE ROTPERA

Omnis enim systematica divisio claudicat lacunisque laborat; optima est, que
paucioribus horret, documentum satis splendidum, mortales non e vero visionis
puncto Naturam contemplari.—O. F, MULLER.

Tous les ordres des étres naturels ne forment qu’une seule chaine, dans laquelle
les différentes classes, comme autant d’anneaux, tiennent si étroitement les unes aux
autres, qu'il est impossible aux sens, et 4 imagination méme, de fixer précisément
le point, of quelqu’une commence ou finit.—LEIBNITz.

Dum inter ea, que determinatis characteribus discreta, et certis quasi limiti-
bus inclusa sunt, semper intermedie quedam species reperiuntur, que, utriusque
proxime accedentis speciei, aliquid possideant, et ita copulationem quasi duarwm
diyersarum specierum constituant; colorum ad instar, qui ita commiscentur et
quasi confluunt, ut nemo veros cujusque fines determinare possit.—J. BasTER.

CHAPTER II1.
ON THE CLASSIFICATION OF THE ROTIFERA,

Four attempts have been made to improve upon Ehrenberg’s classification : viz. that of
Dujardin in 1841, of Leydig in 1854, of Dr. 8. Bartsch in 1877, and of Herr K. Eekstein
in 1883. I do not intend to discuss here the various merits and faults of these
five systems; it is enough to say that they all seem to have the fault of needlessly
bringing together animals that are different in structure, while separating others that
closely resemble each other; I say ‘needlessly’ because perfect classification appears
to be an impossibility, except at that fleeting stage of our knowledge when none but
the commoner genera are known to us. These usually differ from each other in a marked
fashion, the very fact of their wide-spread co-existence being perhaps due to their differ-
ing so as not to interfere with each other.

When, however, continued search has brought to light the rarer forms, these usually
prove to be links between the more common ones; and then the troubles of the classifier
begin. For these strange forms, which are the delight of the naturalist, are the classifier’s
despair. Do what he will, no system that he can devise will put into Nature those
sharp divisions and well-marked gaps that are so dear to him, but of which she knows
nothing.

Nature has but one law, that of infinite variety; and the utmost that the classifier
can do is to group his animals as well as he can round certain typical forms, content to
have the symmetry of his plans and the sharpness of his definitions marred by forms
that perversely bear the characteristics of two or three of his types, in nearly equal
proportions. .

He may take comfort, nevertheless; for, even if he had been able to invent a
thoroughly satisfactory classification, it is from the nature of the case written in sand.
He can never say as he throws down his pen:

Exegi monumentum wre perennius ;

for it is almost certain that the fresh discoveries of the next ten years will require his
work to be re-cast; and no higher praise could be given to Ehrenberg’s system than
that, in spite of new discoveries and its own obvious faults, it has reigned alone for nearly
five times the usual period.

The Rotifera may first be divided into four natural orders, according to their modes
of locomotion, and the structure of the foot. The first of these ideas appears in
Dujardin’s classification, and the second in Leydig’s, and they are both excellent; for
there are Rotifera that swim by means of their ciliary wreath, and skip by the help of theiy
arthropodous limbs; Rotifera that swim only with their wreath ; others that swim and
creep like a leech ; and lastly, some that, when adult, are stationary. Moreover, in three
of these four orders there is only one form of foot in each order, and that form is unlike
those of the other two; and although in one order there are more forms of the foot than
one, still they are all unlike the forms of the other three.

Nor is this all. The natural character of these four orders is further shown by there
being other important points of structure, in which the animals comprised in each order
at the same time resemble each other and differ from those of the other orders.

26 THE ROTIFERA.

I have named these orders as follows :

I. RHIZOTA (the rooted). Fixed when adult.
II. BDELLOIDA (the leech-like). That swim with their ciliary wreath, and creep like a leech.
III. PLOIMA (the sea-worthy). That only swim with their ciliary wreath.
IV. SCIRTOPODA (the skippers). That swim with their ciliary wreath, and skip with Arthropodous
limbs.
Now, the creatures contained in these orders, with a few exceptions, differ from each
other, first in their habits, and secondly in the following points :
I. In the structure of the foot.
II. In the arrangement of the ciliary wreath.
IIL. In the form of the trophi.

I. In the structure of the foot.
(1) The Rhizotic foot is transversely wrinkled, and ends in a sort of sucking disk
(fig. 16) or cup (fig. 17). It is not retractile within the body, it never has telescopic
joints, nor is it ever furcate.

—“—
Fig. 16.—Rhizotic foot. Vig. 17.—Rhizotic foot. Fig. 18.—Bdelloidic foot, Fig. 19.—Scirtopodic foot.
(Lloscularia campanulata) (Melicerta ringens ) (Rotifer citrinus) (Pedalion mirum)

(2) The Bdelloidic foot (fig. 18), on the contrary, is telescopic, retractile, furcate, and
is never transversely wrinkled, nor terminated by a sucking disk.
(3) The Scirtopodic foot (fig. 19) is unique; it is divided into two unconnected,
smooth, jointless styles, each ending in a ciliated expansion.
(4) The Ploimic foot is various in shape, but is always unlike that of any other
order ; for—
(a) if transversely wrinkled, it is yet retractile within the body, and almost invari-
ably furcate ;
(b) if jointed and furcate, it is not also telescopic ;
(c) occasionally it is absent altogether.
II. In the arrangement of the ciliary wreath.'
(1) The Rhizotic ciliary wreath is of two forms :
(a) The first encircles the body twice, by bending on itself; thus inclosing the
mouth, and having a dorsal gap between the points of flexure, figs. 20, 21.

Fig. 20.—Rhizotice wreath (a), front view. Fig. 21.—Rhizotic wreath («), side view. Fig. 22.—Rhizotie wreath (6),
( Melicerta ringens) ( Melicerta ringens ) seen from above.
(Floscularia campanulata)
‘ In figs. 20 to 25, cw is the ciliary wreath ; pw is the principal wreath ; sw is the secondary wreath ;
bf the buccal funnel; Jp the lips.

ON THE CLASSIFICATION OF THE ROTIFERA. 27

(6) The second form is a simple segment of a cirele, placed on the ventral side
above the mouth, fig. 22.

(2) The Bdelloidic wreath is also of two forms :

(c) The first, like the Rhizotic wreath (a), is a double wreath surrounding the body
twice, and inclosing the mouth ; but, unlike the Rhizotic, it has two gaps
instead of one, viz. a dorsal gap between the points of flexure, and a ven-
tral gap in the upper wreath opposite to the mouth.

(d) The second form of Bdelloidic wreath is a mere furring of the corona on
its ventral surface, as shown in fig. 25.

(8) The Ploimic wreath is very various in shape, but is never Rhizotic, while it is
Bdelloidic only in one genus.!

sw
Fig. 23.—Bdelloidic wreath (c), Fig. 24.—Bdelloidie wreath (c), Fig. 25.—Bdelloidie wreath (d),
from above. side view. (Adineta vaga)
(Rotifer citrinus ) (Rotifer citrinus)

(4) The Scirtopodie wreath is of Bdelloidic type.

Ill. In the form of the trophi.

If we disregard two genera ? of the Ploima (not one-fifteenth of the whole number
of Ploimic genera), we can then say that the first three orders differ also in the forms
of their trophi. For—

(1) The Rhizotic trophi are either malleo-ramate,’ fig. 26, or wncinate,? fig. 27.

(2) The Bdelloidic trophi are always ramate,? fig. 28.

(8) The Ploimic trophi are of various forms; but are never Bdelloidic, and are
Rhizotic only in two genera.”

(4) The Scitrtopodic trophi are of a Rhizotic type, being malleo-ramate, fig. 26.

Fig. 26.—Malleo-ramate. Fig. 27.—Uncinate. Fig. 28.—Ramate,
(Melicerta ringens) (Stephanoceros Eichhornii) (Rotifer citrinus)

Now, in reviewing the points of agreement and of difference in the four orders, we
may at once set aside the fourth order, the Scirtopoda, as unmistakably separated from
the others.

This order contains but one family, which has only one genus, and that genus
itself consists of only one species. In fact, it has been formed to contain that
remarkable creature Pedalion nirwm, which I discovered at Clifton in 1871. This

1 Pterodina. 2 Triarthra and Pterodina.

8 For the explanations of these technical terms, see p. 29.

4 TI pass over for the present Dr. Schmarda’s Hexarthra polyptera, and will discuss it under the
Pedalionide.

28 THE ROTIFERA.

Rotiferon has six hollow limbs continuous, in true Arthropodous fashion, with the body-
cavity, and worked by opposing muscles passing down them, and is thus plainly linked to
the Crustacea and Insecta. Pedalion, in fact, is a Nauplius larva, and is yet a Rotiferon.

Order IV., then, is sufficiently separated from the rest by its Arthropodous limbs,
and by the use made of them; and of the other three orders, it has been shown
above that, if we disregard some points of only two genera, we may say of orders I. II.
III. that they differ inter se in their habits, and in the structure of their feet, trophi,
and ciliary wreaths.

This seems a satisfactory first step towards classification; but it is only fair to the
reader to warn him that it has been gained by omitting some parasitic Rotifera, as well as
a few very troublesome forms, such as Trochosphera, Apsilus, Microcodon, &e.

I have dwelt on the differences in structure, as well as in habits, between the four
orders, in order to show that these four groups are natural; but I do not propose to
use as ordinal characteristics any others than the mode of locomotion and the structure
of the foot ; and for this reason, that each of the first three orders has more than one
form of the trophi, or of the ciliary wreath, or of both.

The Rhizota, for instance, have two forms of the trophi, and two of the ciliary wreath.
The Bdelloida have two forms of wreath, and the Ploima have many different forms of
both wreath and trophi.

Before I proceed to divide these four orders into families, I must, however, digress
a little to explain and name the various types of trophi, as the classification partly depends
upon them.

Mr. Gosse’s treatise on ‘‘ The Manducatory Organs in the Class Rotifera’”’ essays to
show that these organs present seven principal types of structure, distinguished from
each other by the prominence of some particular part.

To make this clear, it may be as well to re-state that, inthe mastax of a Brachionus,
there are two hammer-like bodies or mallei (fig. 29, ms), which work on a kind of split
anvil or incus (fig. 29, 7s), and that each mallews consistg
of an upper part, the head or wneus (fig. 29, ws), and of
a lower part or handle, the manubriwm (fig. 29, mm) ;
while the incws consists also of two parts, the upper
divided into two symmetrical halves, the rami (fig. 29,
rs), Which are supported on the lower piece or fulerwm
(fig. 29, fn).

Now, in Brachionus all the trophi are well developed,
but the other typical manducatory organs may be arranged
in a series in which the mallei are successively degraded,

Fig. 29.—Malleate. while continually greater prominence is given to the inecus ;

at least in all but three types; and in two of these the

rami and unci are the prominent parts, while the third is distinguished by the close
connection of the mallet and the ram.

The typical trophi may, then, be named as follows:

1. Malleate (fig. 29).
Mallei stout; manubria and unci of nearly equal length ; unci 5- to 7-toothed ; fulerum
short; as in Brachionus urceolaris.
2. Sub-malleate (fig. 30).
Mallei slender ; manubria about twice as long as the unci; unci 8- to 5-toothed ;
as in Huchlanis deflexa.
8. Forcipate' (fig. 81).
Mallei rod-like ; manubria and fulcrum long ; unci pointed or evanescent ; rami much
developed and used as a forceps; as in Diglena forcipata.

1 In Furcularia, and in a few other genera, the rami as well as the mallei are rod-like; and the

ON THE CLASSIFICATION OF THE ROTIFERA. 29

4. Incudate (fig. 32).

Mallei evanescent ; rami highly developed into a curved forceps ; fulerum stout ; as
in Asplanchna Hbbesbornit.

5. Uncinate (fig. 27).

Unci 2-toothed ; manubria evanescent ; incus slender; as in Stephanoceros

Hichhornit.
ee

Fig. 32.—Incudate.

ms us

fim
Fig. 30.—Sub-malleate. Fig. 31.—Forcipate.

is

6. Ramate (fig. 28).

Rami sub-quadrantic, each crossed by two or three teeth; manubria evanescent ;
fulcrum rudimentary ; as in Philodina roseola,

7. Malleo-ramate (fig. 26).

Mallei fastened by unci to rami; manubria 8 loops soldered to the unci; unci 3-
toothed ; rami large, with many striz parallel to the teeth; fulerum slender; as in
Melicerta ringens.

Now, the seven Rotifera, made use of above to yield examples of typical trophi, are
very distinct from each other, and show that the form of the trophi is one good charac-
teristic for separating the families. But a difference in the shape and disposition of the
corona, and of its ciliary wreath, generally accompanies a difference in the manducatory
organs ; and the three together will serve as good guides to a division of the four orders
into families.

In one of the sub-divisions of the Ploima, however, the corona, ciliary wreath, and
trophi are often difficult of determination ; but just where these guides desert us, a new
character, viz. the lorica, comes to our aid, and shows such well-marked differences in
shape and structure, as to enable us to divide this sub-order (the Loricata) into fairly
natural groups. The Loricata are so called from the integument of the body; which,
from the distribution of chitine throughout the tissue, is hardened into a stiffened coat
or shell (dorica, a coat of mail) inclosing, more or less completely, the internal organs.
In the Jl-loricata the integument is soft and flexible ; but there is, unfortunately, no very
sharp division between the two sub-orders in this respect; as every variety of integu-
ment exists, from the hard, dense coat of Dinocharis, to the tough yet flexible covering
of Rattulus, and the perfectly soft cuticle of Albertia.

The following scheme, then, is an attempt to divide the four orders of Rotifera into
families, by means of the various characters which I have just detailed : of course, there
are some genera which do not readily fall into the arrangement; but this is only what
is certain to happen to every possible scheme of classification.

Such difficulties must attend every attempt to marshal Nature’s endless varieties into

whole apparatus looks like one forceps within another. To this variety of the forcipate trophi the
term virgate will be applied.

30 THE ROTIFERA.

well-marked battalions. Nature knows no hard lines of separation; and the best of
classifications can be only that which contains the fewest faults : as Miller has forcibly
said, ‘Optima est, que paucioribus horret.’

Order I. Rutzotva.

Fixed when adult ; foot transversely wrinkled, not retractile within the body, ending
in a sucking disk or cup.

Fam. 1. Flosculariade (PI. C, fig. 1).

Corona produced longitudinally into setigerous lobes ; buccal orifice central; ciliary
wreath a single half-circle above the buccal orifice ; trophi uncinate.!

Fam. 2. Melicertade (Pl. C, fig. 2).

Corona not produced into setigerous lobes ; buccal orifice lateral; ciliary wreath a
marginal continuous curve, bent on itself at the dorsal surface, so as to encircle the
corona twice, with the buccal orifice between its upper and lower curves, and haying also
a dorsal gap between its points of flexure; tropii malleo-ramate.!

Order II. Bprnunorpa.

That swim with their ciliary wreath, and creep like a leech; foot wholly retractile
within the body, telescopic, furcate.

Fam. 8. Philodinade (P1. C, fig. 3).

Corona two transverse circular lobes; ciliary wreath a marginal continuous curve
bent on itself at the dorsal surface, so as to encircle the corona twice, with the buccal
orifice between its upper and lower curves, and having also two gaps, the one dorsal
between its points of flexure, and the other a ventral gap in the upper curve opposite to
the buccal orifice: trophi ramate.!

Fam. 4. Adinetade (PI. C, fig. 4).

Corona a flat ventrally placed surface ; ciliary wreath the furred ventral surface of
the corona; trophi ramate.}

Order III. Puoima.

That swim with their ciliary wreath, and (in some cases) creep with their toes.

Sub-order. I]-loricata.

Foot, when present, almost invariably furcate ; but not transversely wrinkled ; rarely
more than feebly telescopic, and partially retractile. :

Fam. 5. Microcodide.

Corona obliquely transverse, flat, circular; buccal orifice central; ciliary wreath a
marginal continuous curve encircling the corona, and two curves of larger cilia, one on
each side of the buccal orifice ; trophi forcipate!; foot stylate.

Fam. 6. Asplanchnade (PI. C. fig. 7).

Corona two transverse, flattened, confluent cones, with their summits distinct ;
ciliary wreath single, marginal ; trophi incudate! ; intestine, cloaca, and foot, absent.

! For description of these technical terms, see pp. 28, 29.

ON THE CLASSIFICATION OF THE ROTIFERA. 31

Fam. 7. Synchetade (Pl. C. fig. 6).

Corona a transverse spheroidal segment, sometimes much flattened, with styligerous
prominences ; ciliary wreath a single interrupted marginal curve, encircling the corona ;
trophi forcipate!; foot minute, furcate, or absent.

Fam. 8. Triarthrade.
Corona transverse; ciliary wreath single, marginal, fringing the buccal orifice ;
trophi malleo-ramate!; foot absent.

Fam. 9. Hydatinade (P1. C, fig. 5).

Corona truneate, with styligerous or ciliated prominences ; ciliary wreath two parallel
curves, the one marginal fringing the corona and buccal orifice, the other lying within the
first, the styligerous prominences being between the two ; trophi malleate!; foot furcate.

Fam. 10. Notommatade.

Corona obliquely transverse ; ciliary wreath one of interrupted curves and clusters,
usually with a marginal wreath surrounding the buccal orifice ; trophi forcipate'; foot
furcate.

Sub-order. Loricata.

Corona and ciliary wreath various in shape, but never Rhizotic, and Bdelloidic only
in the Pterodinade: trophi of different types, but never Bdelloidic, and Rhizotie only
in the Pterodinade.

Division I.

Foot jointed, stylate or furcate ; not transversely wrinkled, nor wholly retractile.

Fam.11. Rattulide.

Lorica entire, cylindrical, without angles ; trophi asymmetrical.

Fam. 12. Dinocharide.
Lorica entire, vase-shaped, sometimes facetted; head distinct, with a chitinous
covering ; trophi symmetrical.
Fam. 13. Salpinade.
Lorica compressed, cleft down the back, the two halves united by a membrane, so as
to form a dorsal furrow.
Fam. 14. Huchlanide (P1. C. fig. 10).

Lorica depressed,’of two dissimilar plates, one dorsal and one ventral, united by a
membrane so as to form a lateral furrow.

Fam. 15. Lepadellade.
Lorica depressed, broad, closed beneath ; head distinct, surmounted by a retractile,
arched, chitinous plate.

Fam. 16. Coluride.

Lorica compressed, open beneath ; head distinct, surmounted by a retractile, arched,
chitinous plate.

1 For description of these technical terms, see pp. 28, 29.

82 THE ROTIFERA.

Division IT.
Foot transversely wrinkled, wholly retractile, furcate or ending in a ciliated cup ;
sometimes absent.
Fam. 17. Pterodinade (Pl. C. fig. 9).

Lorica greatly depressed, entire, of two nearly equal plates, soldered together at the
edges; corona and ciliary wreath those of the Philodinade; trophi malleo-ramate ! ;
foot ending in a ciliated cup.

Fam. 18. Brachionide (PI. C. fig. 8).
Lorica depressed, entire, dorsally arched, generally armed with anterior and posterior
spines ; corona transverse with styligerous prominences ; ciliary wreath single, marginal,
fringing the buceal orifice ; trophi malleate'; foot furcate, or absent.

Order IV. Scrrropopa.

That swim with their ciliary wreath, and skip with Arthropodous limbs ; foot replaced
by two dorsal, stylate, wnconnected appendages, ending in ciliated expansions.

Fam. 19. Pedalionide (Pl. C. fig. 11).

Corona truncate; ciliary wreath a marginal continuous curve, bent on itself at the
dorsal surface, so as to encircle the corona twice, with the buccal orifice between its
upper and lower curves; having also two gaps, the one dorsal between its pomts of
flexure, and the other a ventral gap in the upper curve opposite to the buccal orifice ;
trophi malleo-ramate.'

The further subdivision of each family into genera will be given with the description
of that family.

1 For description of these technical terms, see pp. 28, 29.

Cie AGP iy, alle Vie

ON THE HAUNTS AND HABITS OF
TE ROME TEA:

Nonne vides, quecunque mora fluidoque calore
Corpora tabuerint, in parva animalia verti ?
Ovip, Metam. xv. 862.

Equidem tum Nature rerum gratias ago, cum illam non ab hac parte video,
que publica est, sed cum secretiora ejus intravi.

Curiosus spectator excutit smgula et querit. Quidni querat? Scit illa ad se
pertinere. Quantum enim est, quod ante pedes jacet.

Seneca, Nat. Quast. pref. (adapted by O. F, MULLER).

*T is born with all: the love of Nature’s works
Is an ingredient in the compound man,
Infused at the creation of the kind... .
It is a flame that dies not even there
Where nothing feeds it: neither business, crowds,
Nor habits of luxurious city life,
Whatever else they smother of true worth
In human bosoms, quench it or abate.
Cowrerr, The Task.

CHAPTER IV.
ON THE HAUNTS AND HABITS OF THE ROTIFERA.

Txart the first thing to be done is to catch your game, isa maxim as applicable to Rotifera
as to hares; and it is no less true of these that to hunt for them successfully requires
some knowledge of their haunts and habits. To carry away from a pond’s side a bottle
of dirty water full of slimy weed, is by no means a good plan for catching these animals,
even the commonest and coarsest. It is true that there are some fine forms which may
be found in very dirty ponds, or even in dirtier puddles: for instance, there can hardly
be too dark a farmyard puddle for Hydatina senta, which rejoices in the draimings of
a manure-heap, even when the water is of so deep a colour that it is impossible to see the
animals in it when you have got them. T'riarthra, too, and the beautiful Notops! clavulata
are to be met with in cattle ponds, where the water is like pea-soup; and Brachioni of
all kinds rejoice in such places, especially when green with Huglene and alive with the
motile seeds of alge. Indeed, there is one Brachionus, B. angularis, whose presence in
a pond bids us put up our bottles and go elsewhere, as it likes water that will support
hardly any Rotiferon but itself.

Floscularia, Stephanoceros, Melicerta, Limnias, and C8 cistes are, of course, to be
found only in such places as pond weeds will grow in healthily. Old ponds that have been
left long undisturbed are their favourite haunts. F'losculariais a very wide-spread genus,
at least so far as one or two species are concerned; and these may be looked for with
every prospect of success in any such pond. Most of the finer and rarer kinds have
been found in the Scotch lakes by Mr. Hood, who during the last four years has doubled
the number of recorded species by his discoveries in the lochs round Dundee.

Stephanoceros, thowzh by no means a rare Rotiferon, is more partially distributed ; it
is found often enough in ponds near London and Birmingham; but I have not heard
that a single specimen has ever been met with in the neighbourhood of Clifton.

It appears also to be rare in Scotland ; as Mr. Hood has found it only once or twice,
in marsh-pools in Perthshire.

Melicerta ringens is to be found almost everywhere. It has even been seen swarming
in one of the aquaria in the parrot-house in the Clifton Zoological Gardens. The roots
of duckweed, the fibres of alg, the leaves of Myriophyllum, and of all sorts of water
plants, bear this very common species, as they do also the tubes of Limnias and Gicistes.
Lacinularia and Megalotrocha have similar tastes, but are less frequently met with,
especially the latter. This must be a comparatively rare genus, asit has been sent to
me but three or four times in many years. Cephalosiphon is also rare. I once
found a large colony of it, on a water weed at Nailsea in the big pond near the railway
station, and it has been sent to me from Cheltenham and London ;? but I never met with
it again.

Conochilus is a lover of clear water. I have found it in Loch Lomond, and Dr.
Imhoff has obtained it, in abundance, in the middle of Lake Zug. It is common enough

1 Notommata clavulata ; Ehr.
2 Miss Saunders, to whom I am indebted for the specimens, says: ‘‘ It is curious I never before came
across this tube-dweller in the hundreds of pools I have searched.”

36 THE ROTIFERA

in clean ponds round about London, and Mr. Hood has met with it in the Perthshire
lochs.

The Notommatade and Philodinad@ have a very wide range. The alge of ponds
always hold many species, and many haunt the sediment that les on the mud of the
bottom. Some of the latter are to be found in gutters of houses, in water-butts, on the
blades of wet grass, anywhere indeed where dust can fall and moisture can follow. For the
eggs of the Rotifera are blown away by the wind from dried-up puddles, and are scattered
broadcast through the air; and some of the creatures they give birth to can exist appa-
rently under almost any kind of moist conditions.

The Asplanchnade fortunately are as indifferent to their quarters as they are large
and handsome. I have found them in roadside ditches thickly covered with Lemna, in
farmyard ponds, in the clear water of a miniature lake, and in a foul yellow-green duck
puddle in which the fluid (it could not be called water) was so thick that it had to be diluted
with five or six times its own bulk, before anything could be seenin it. An Asplanchna is
the very beau-ideal of a Rotiferon fora beginner. It is very large and transparent; it swims
slowly ; and it generally occurs in great numbers. Moreover, its male is even more
transparent than the female; a mere living bubble, thinner and clearer than the finest
blown glass. Unhappily, they are as capricious as they are charming; for a pool may be
full of them to-day and deserted to-morrow ; and, so far as my own experience goes, they
do not occur in the same spot year after year as many Rotifera do.

The Pterodinade and Euchlanide are dwellers in clear ponds, and rather solitary
in their habits. Ona warm sunny day the latter may be captured by skimming off the
Lemna, and floating bits of leaves and stems, that are driven to the leeward corner of a
pool. If the bottle be then allowed to stand a few minutes till the water is clear, a
Euchlanis will often be found slowly gliding up the glass with its long toes pressed
against it. It is always worth while to capture it at once with a pipette, and put it into
a small tube along with any others of the same kind, as a live Huchlanis, properly ex-
hibited under dark-field illumination, is one of the choicest treats that the Rotifera afford.

The Pterodinad@ are almost always creeping about the alge on the sides of the pond.
IT never but once have seen any other than solitary specimens, but that exception was a
notable one. I then found swarms of them in the small space in which the sluice gate of a
pond worked. It was not more than a foot square by about four feet deep, and was mantled
over by duckweed. Out of this unlikely spot they were dipped by hundreds, while not
one could be found in the pond itself. Of course the duckweed came up with the Ptero-
dine, though as little as possible was taken, on account of the disagreeable way in which
it clings to every pipette put into the bottle. On this occasion, however, I found it of
ereat service; for, on inspecting the catch at home with a hand-lens, I noticed that
the Rotifera were attached in clusters to some of the roots of the duckweed. Watch-
ing for a favourable opportunity, I whipped one of the Lemn@ out of the water
so suddenly, that the creatures had not time to let go their hold. Then cutting off the
green head, I coiled the stem into a circle on a glass slip, and covered 1t with thin glass.
It was impossible to conceive a more beautiful sight than this natural cage now afforded
me. Thirty or forty shields of living glass were flashing across the field of view in every
direction; some were adhering to the stem, swaying backwards and forwards so as to
present themselves in every point of view, while others were moored to the glass cover,
thus giving an admirable opportunity of making out their structure.

It was a memorable occasion, but I never had such a chance again.

I haye yet to speak of the Synchetade among the free-swimmers. Both the genera
included in this family are to be found in open water; and both alike shun dirty ponds ;
though in different degrees, for Syncheta is absolutely intolerant of them; while I have
dipped up Polyarthra from the hollows of a muddy bottom where once a pond had
been.

Both genera are tolerably common, and are often to be caught in considerable
numbers. The habits of the two chief species of Syncheta, viz. S. mordax and S.

ON THE HAUNTS AND HABITS OF THE ROTIFERA. 37

tremula, are very different. The former is the swiftest and most restless of the Rotifera ;
it is the very swallow of the waters, ever whirling round and round in endless spirals,
and never still for a single instant from its birth till its death; but the latter may be
constantly seen drifting along in some gentle current, while twisting round at the end of
a long thread spun from its toes, and fastened to some floating object.

Of course, creatures with habits like these can be captured only by making random
dips in the water, now at the surface, now deeper down—here in the sunshine, and there
in the shade; for even Rotifera have their fancies, and are sometimes swarming in one
particular spot, while all the rest of the pond is deserted by them.

I have, however, noticed that they specially affect the neighbourhood of a forest of
weeds growing up from the bottom ; waltzing up and down outside of them in myriads,
like enats under the trees in summer.

There is yet another free swimmer that avoids the shore, and sails out into the open
sea; viz. Anwrea longispina. This curious creature has a lorica like a Greenlander’s
canoe, or a University eight, and it keeps off from the weeds and alge, as if fearing lest
it should be entangled for life if it once got among them. It was discovered by Professor
D.S. Kellicott in Niagara water at Buffalo, U.S., in 1879, and was found almost imme-
diately afterwards in the Olton Reservoir, near Birmingham and since then in Lake
Zug in Switzerland. It appears to be a rare species, though its rarity may be due
partly to the fact that it often requires a boat to catch it; and an ordinary Rotifer hunter
can hardly be expected to add this to his apparatus.

The known habitats of the Pedalionide are at present very few. I had the good
fortune to be the first to light on Pedalion mirwm. It was in July 1871 that I found
it in a small roadside pool at the top of Nightingale Valley, close to Clifton. Soon
afterwards I dipped it from a fine old pond at Abbot’s Leigh, about two miles distant from
Nightingale Valley. It reappeared in this pond in the following year, but since then it
has not revisited the neighbourhood. It has been met with several times near Chester
and Birmingham, and on one occasion it was tolerably abundant in the warm water-lily
tank in the Duke of Westminster’s gardens at Eaton.!

Dr. L. K. Schmarda discovered in Egypt, in 1858, in some brackish pools near
Kl-Kab, a six-limbed Rotiferon, Hexarthra polyptera, which evidently belongs to the
same family, though it must be placed in a different genus. He says that there were
great swarms of them distinctly visible to the naked eye, in a pool of very transparent,
colourless water, of a strong brackish taste.

Now, a Rotiferon that is equally at home in dirty puddles, clear ponds, warm-water
tanks, and brackish pools, ought not to be a rare one: and yet Pedalion is rare.

Possibly its apparent rarity is due to its being constantly mistaken for an Entomo-
stracous larva. I was on the point of throwing the water away, when I first
dipped Pedalion out of the pool in Nightingale Valley. Its skipping movement is so
precisely that of the young of a Cyclops, that I thought I had caught nothing more
valuable than these ever-present nuisances. Fortunately I noticed that, unlike them,
my captives seemed to glide along after every skip, stead of stopping stock-still to
gather breath for a fresh jump ; and so, thinking that they might possibly be some large
sort of Polyarthra, took them home for further investigation. But it is very probable
that Pedalion has been thrown away hundreds of times, and will be so again, as this
happened to me after nearly twenty years’ experience in catching Rotifera.?

Rotifera may often be seen perched just under the plumed heads of one of the fresh-

1M. J. Barrois described, in the Revue Scientifique, No. 13, 1877, p. 303, a marine Rotiferon under
the name Pedalion, and gave an account of its embryology. His description, however, shows that the
animal was of the genus Syncheta.

2 It is a pity that Pedalion is not more frequently met with, as there are some points in its structure
that yet remain to be cleared up; and as it is such a striking link between the Rotifera and the
Arthropoda. Myr. T. Bolton, of Birmingham, has, however, succeeded in preserving specimens as micro-
scopic objects, and they can generally be obtained from him.

38 ; THE ROTIFERA.

water zoophytes, wisely making use of the stronger currents produced by the ciliated
tentacles of their hosts, in order to bring grist more easily to their own mills. I have
had sometimes quite ‘‘a happy family” of them in the field of view at once; a Brachionus,
a Philodina or two, and a Melicerta, all attached to the neck of a Plwmatella, and all
eagerly whirling their wheels in order to divert to their own throats a portion of the
currents that swept down to them from above. Nor was this all; for the Melicerta in
its turn had the top of its tube turned to the same use, and bore, as closely under its
wheels as possible, the tiny case of one of its own offspring.

Limnias ceratophylli and Melicerta ringens carry this semi-parasitical habit to a
sreat extent. Clusters of two or three generations all attached to one tube are not at
all uncommon in the former species; and I once found in Nailsea pond a large Lim-
nias bearing up no fewer than fourteen of its own descendants. Melicerta ringens, too,
in America,! is frequently met with in large adhering clusters, but in England it is
usually a solitary species. However, this is not invariably the case ; for not long ago I
had the pleasure of seeing as many as thirty-four live Melicerte attached to one another.”
They were of all ages and sizes, and were grouped round one large tube, so as to form a
striking example of a natural co-operative society. Nor is this the only way in which the
Rotifera show their capacity for fighting the battle of life. Myvery animal is limited by its
own powers to a certain space, beyond which its excursions cannot possibly extend.
Its food and its mate must be found within these limits; and when these two imperious
wants are satisfied, there is but little time or strength left for travelling. But it would be
an obvious advantage to many creatures if they could be carried about from one spot to
another without tiring their own muscles—ready to slip off, at any favourable opportunity,
“to fresh woods and pastures new.’’ Now this is precisely what some of the Brachiont
and Philodine contrive to do; for they may be seen riding in clusters on the backs and
sides of the Entomostraca, or thickly fringing the legs and side plates of the water wood-
louse.?

Whenever I have caught a water-flea 4 so encumbered, and have placed it in a live
box to see the Rotifera it carried, they have soon deserted their captive steed, and have
swum off as if to search for a more serviceable one.

There are, too, some Rotifera whose structure has been adapted to give them a good
srasp of their host, or even to enable them to pierce its skin, and so suck its juices for
their own support.

Balatro calvus, for example, has been found® in the Seine (Canton de Genéve)
creeping on the bodies of small water-worms which it habitually infests, and having two
ereatly enlarged foot-processes, which probably enable it to take a firm hold.

Another Rotiferon, Callidina parasitica, is always found attached to the thoracic
or abdominal appendages of the fresh-water shrimp ® and water wood-louse, and limits
its journeyings to creeping about on the body of its host; while the strange creature
Drilophaga Bucephalus holds on by its altered jaws to the hind segments of a fresh-
water worm, Lwmbriculus variegatus, and sucks the animal it clings to.

This parasitic Rotiferon was discovered in North Bohemia in the great pond at Hirse-
berg, in the banks of which the Lwmbriculus is found in immense numbers. The worm
buries the fore part of its body in the mud, and moves its naked hinder segments like a
pendulum in the water. But no such gentle motion will unfasten the grip of the
Drilophaga, which is so firmly attached to the worm’s skin that it can be dislodged only
by using considerable force.

1 I am indebted to Mr. Galloway C. Morris, of Philadelphia, U.S., for this information. A cluster
of tubes that he sent to me contains twenty-eight specimens of various sizes adhering together.

2 It was found near Clifton by Mr. E, C. Bousfield, and is drawn in Pl. V. fig. 1, e.

8 Asellus vulgaris. 1 Daphnia pulex.

5 By M. Ed. Claparéde. See Ann. Sci. Nat. Zool. 5 Ser. vol. viii. 1867.

6 Gammarus pulex. Mr. H. Giglioli, who discovered this species, says that he has never found it
anywhere else; and that out of 700 Gammari from different localities, not one was free from the para-
site. Quart. J. Micr. Sci. N. Ser. vol. ili, 1863, p. 237

ON THE HAUNTS AND HABITS OF THE ROTIFERA. 39

If the Rotifer hunter can rise to a pitch of enthusiasm, which I confess I have never
been able to attain to, he may follow Dujardin’s example, and, by making incisions ! in
the sides of earth-worms and slugs, obtain from the expressed fluids the entozoic
Albertia verniculus. The same creature has been seen inside Nais proboscidea,? and an
allied species (Albertia crystallina) in the viscera of Nais littoralis,’ while the Synapte of
the Channel Islands have been found‘ to carry within their body-cavity a minute Rotiferon
only ;3, of an inch in length.

But I have not yet exhausted the list of these strange dwelling-places. A pretty
little Rotiferon, Notommata parasita, may be found swimming about within the beautiful
spheres of Volvox globator, or lodged within the embryo globes when almost ready to
escape from the parent sphere. ‘‘On examining several specimens of Volvox with a
pocket lens we may frequently detect such as are thus tenanted, by perceiving a spot
differing from the young clusters in form and colour. These spots are found to be
the Notommata, snugly ensconced within the globe, in the spacious area of which it lives
at ease, and swims to and fro like a gold fish in a glass vase. We sce it for the most
part, however, clinging to the inner surface of the circumference, engaged in devouring
the green monads with which the gelatinous surface is studded, or else eating away the
embryo clusters.” > Volvox globator is common enough in most neighbourhoods, and may
be met with it even in clear rain puddles in quarries and plantations; while in two or
three ponds near Clifton it is sometimes so abundant as to give a green hue to the water ;
and yet I have never seen its guest here, nor do I know anyone in the neighbourhood
who has ; so it can scarcely be a common species.

The reproductive cells of Vaucheria—a thread-like alga which grows on pond walls
and in many moist places—are the homes of another Notommata, N. Werneckiit. This
parasitic Rotiferon passes a small portion of its youth in the open water; but it soon re-
turns to a lifelong imprisonment in the green cells in which it was hatched, and where
it undergoes very singular changes of form. Its presence in the Vaucheria may be
detected by the unusual size and shape of the reproductive cells, dnd by their containing
a black spot which is the animal’s stomach.®

Some further means of obtaining Rotifera have yet to be mentioned.

Tf a little of the mud or rotten leaves at the bottom of a dried-up pool, in which
Rotifera have been observed, is brought home and allowed to lie in a vessel of water, the
chances are in favour of there being in the mud some of their eggs, and of their
ultimately hatching. I have often adopted this plan with success, especially when
some rare species has been discovered in a little pool due only to the rain, and drying up
after two or three days’ fine weather. Unluckily the mud too frequently harbours an
abundance of small worms also; and these are disagreeable to see and troublesome
to deal with, for they are liable to starve, die, and taint the water.

Rotifera also may be produced at home by placing infusions of hay, leaves, &c. in
some vessel out of doors. No very great variety is to be obtained by such methods ; but
it is always as well to try it, and to have a good-sized pan in the garden, full of soft
water, ito which rubbish from pond-gatherings may occasionally be thrown. These,
and the chance droppings from the air into the pan, will sometimes give the student, at
his own door, species which he would otherwise have to travel far to find.

Many of the Rotifera may be kept indoors in vessels in which there is a healthy growth
of Myriophyllum, Anacharis, or other water-weed. Mr. Gosse has tried this plan with

1 Ann. Sci. Nat. Zool. 2 Ser. vol. x. 1838, p. 176.
By Mr. P. H. Gosse, in water from a pond at Walthamstow. 3 By M. Max Schulze.

4 By Professor Ray Lankester, Quart. J. Micr. Sci. N. Ser. vol. viii. 1868, p. 54.

5 Mr. P. H. Gosse, Trans. Micr. Soc. vol. iii. 1852, p. 143.

6 Prof. Balbiani, Ann. Sci. Nat. Zool. 6 Ser. vol. vii. 1878. I am not aware that Notommata
Werneckii has been found in England. Probably it would be, were it deliberately searched for. Mr.
F. W. Roper, of Eastbourne, has found a similar species tightly rolled up in a ball inside the leayes of
one of the liver-worts, Lejewria minutissima.

40 THE ROTIFERA.

success, and has lately had thousands of Stephanoceros, Melicerta, Pterodina, &e.,
thriving in tanks and jars in his study. Mr. J. Hood has been equally successful with
Floscularia and Limnias ; and I know of other instances in which a literally constant
stock of the tube-making Rotifera has been maintained in these home preserves.

Indeed, if nothing more is desired than to watch the growth of a couple of generations
or so, an ordinary zoophyte trough is aquarium enough. All that is necessary is, (1) to
take great care that there are not many animals of any kind in it, (2) to keep it ina
subdued light, (3) and at a moderate temperature, (4) and especially to provide the
Rotifera with plenty of their natural food. For, in the great majority of cases, Rotifera
die, when in captivity, of starvation: one moment’s examination of their stomachs will
make that point clear.

Of course, what is their natural food must first be observed under the microscope,
and then it must be provided to them every day by dropping a fresh supply of water
containing it into the trough. It will, therefore, always be necessary to bring away
from the pond, where they were found, a good supply of pond water free from all other
kinds of animals.

Sometimes, however, it is well to make an overfed Rotiferon starve a little, in order to
see its internal structure. Hydatina senta, for instance, is frequently so gorged with dark
green food, that little else can be seen but its distended stomach ; the organization of
Pedalion mirum, too, is often a hopeless riddle, owing to its greedy habits; but drop
either of these creatures into a tube of clear soft water for an hour or so, and it may be
fetched out again in delightful condition for microscopic investigation, and yet perfectly
healthy.

Summing up the various habitats that Ihave just recorded, we see that Rotifera
may be found in rivers, lakes, reservoirs, ponds, ditches, puddles, gutters, and water-
butts; in the mud of dried ponds, in the dust of dried house-gutters, on wet moss and
erass; in the rolled-up leaves of liver-worts, in the cells of Volvox globator and of
Vaucheria, in vegetable infusions ; on the backs of Hntomostraca, and of fresh-water
fleas, wood-lice, shrimps, and worms; in the viscera of slugs, earth-worms, and Naiades,
and in the body-cavities of Synapte. Nor have I yet completed the list; for several
species have been found in the sea. Mr. Gosse says,' “ Syncheta Baltica swims at large
through the water, never resting; it is self-luminous, and is one of the causes of the
phosphorence of the sea. Brachionus Milleri and Pterodina clypeata oceur in brackish
water at the mouths of rivers ; and other marine species may often be detected by searching
with a pocket-lens the glass sides of a well-stocked aquarium.”

Since then these creatures have so wide a range of habitats, it is hardly possible
for anyone, who will take the trouble, not to find some of them near his own home.

To obtain some particular Rotiferon, at a particular given time, is often difficult
enough, if not impossible ; but for one who is content to study these beautiful creatures
as he finds them, there is always a never-ending supply of delightful amusement.

1 Marine Zoology. part i. 1855, p. 107. See also Tenby, 1856, p. 274.

_ EXPLANATION OF THE LETTERING OF

Corona

Lobe of do. :
Styligerous prominence .
Chin.

Ciliated cup

Hook

Horny processes

Foot

Toe :

Ciliary wreath

Principal wreath
Secondary wreath

Taster

Vestibule

Buccal funnel .

Lips : 5
Tube from lips to crop
Crop

Mastax

Us . uneus
| 78 . ramus
fm - fulerum

Trophi | ms
or °

5 malleus |
: : (
Jaws Sane - Incus |

(sophagus

Stomach .

Intestine

Rectum .

Cloaca 5

Salivary gland

Gastric gland .

Foot gland

Lateral canal .

Vibratile tag

Contractile vesicle . Fi P
Ovary : ,
Germ : .
Ovum : .
Oviduet . : :
Penis ‘ 3 3 : ; : ; ; ‘
Sperm-sac . : ‘ 2
Longitudinal muscle

Transverse muscle .

Ganglion . :
Eye : : : :
Dorsal antenna . :
Lateral antenna

Tactile style

Nerve thread .

THE PLATES.

Parts of head and body.

; : 5 5 e |
mm 3 manubrium | Nutritive system.

[

Secreting system.

Vascular system.

et system.
!

Muscular system.

|

Nervous system.

EXPLANATION OF PLATE A.

** In all cases throughout the plates, both the plain and coloured, the figures that have
the initial H attached to them have been drawn from life by Dr. Hudson, and those with the
initial G, also from life, by Mr. Gosse.

BRaAcHIONUS RUBENS and the details of its structure.

9. Malleus, as in nature
10. Incus, side view F A 2
11. Ganglion andeye . ° 3 3
12. Extremity of foot :
13. Male; penis withdrawn (after Dr, Cohn)
14. Male; penis extruded (after Dr. Cohn).
15. Dorsal antenna a
16, Ephippial egg (after Dr. Gonna)

- Dorsal view

. Ventral view; upper half

. Lorica and muscles; dorsal view
A “3 ventral view

Side view d A

. Mastax and trophi; cones view.

. Trophi; ventral view . d

. Malleus expanded by pressure .

BASIE WN
Qe2Qrtht hy
HHaa

In all the above figures the letters signify as follows :—

Se : . styligerous prominence ed. 5 - cloaca
ip c - foot 8g . : - salivary gland
Gc c . toe gg - f - gastric gland
cw. 0 . ciliary wreath Wp © 3 - foot gland
(OF oc . - buceal funnel tc. 5 . lateral canal
lp . é . lips ot. : . vVibratile tag
Mo . é - mastax cu. ° - contractile vesicle
uw. “ . trophi oy. 5 + ovary
ms. - - malleus Go - germ
ws : - uncus om. , - ovum
mm . 5 - manubrium Die 2 - penis
18 4 : - incus 8s - sperm sac
tT ed : . ramus lm. 0 . longitudinal muscle
jm . : . fulerum gn . c - ganglon
@ cesophagus er 5 - eye
Ds : - stomach a. c . dorsal antenna
a intestine a’ lateral antenna
G rectum tse 7 . tactile style

ee iO
ut --

Min

tt

<
Fu 2 Y

ts nN L av &
: Wn WW ///
SOLU i Su Wy
SS SS} , —— Z
) Z

EXPLANATION OF PLATE B.

- Melicerta ringens .

. Trochal dise of Melicerta Starcom, fain Bcore

. Limnias ceratophylli 4

- Trochal dise of Limnias ceratophyl kom bare,
- Rotifer or Philodina 0 a f
. Syncheta Baltica . a ‘ . a 5 - Baster, 1759
- Rotifer macrurus . c
. Brachionus Bakeri

. Philodina or Rotifer

10. Euchlanis

11, Triarthra

12. Actinurus Neptunius

13. Megalotrocha 0
14. Stephanoceros Hichhornii
15, 16. Floscularia ornata
17. Brachionus pala

18. Philodina nevnre ; , 5 0 F "| sobot W718

19. Lacinularia socialis : : 5 : a . Brady, 1755

20. Stephanops cirratus : :

21. Brachionus Bakeri

22. Pterodina patina

23. Salpina . |

24. Euchlanis |

25. Dinocharis -sasttlbsesn . 9 , : 9 9 |

26. Mastigocerca carinata . 3 6 9 9 , ies 1776-1786

Leuwenhoek, 1703-1705

cate aes

Baker, 1753

SONanrkwnde

Bichhorn, 1775

—S -—_— —

27. Notommata tigris .

28, 29. Hydatina senta

30. Notommata longiseta .
31, 32. Lacinularia socialis .
33. Notommata aurita

34, Anurea striata

PB

A=

PLATE C.

Showing the Coronee, Trophi, and Feet of some of the principal

Flosculariade

”

Melicertade

Philodinade .

Adinetadse

Asplanchnade
Syncheetadee
Hydatinadse

Euchlanide

Pterodinade .
Brachionide .

Pedalionide

Families of the ROTIFERA}

Order I. RHIZOTA.

Fig. I. Floseularia campanulata.
Fj Stephanoceros Eichhornii.
Fig. II. Melicerta ringens.

Order II. BDELLOIDA.

Fig. III. Rotifer citrinus.
Fig. TV. Adineta vaga.

Order III. PLOIMA.
Sub-order In-Loricata.
Fig. V. Asplanchna Ebbesbornii.
” Syncheta mordax,.
” Hydatina senta.
Sub-order Lorrcara.
Division I.
Fig. VI. Euchlanis deflexa.
Division IT.

Fig. VI. Pterodina patina.
Brachionus urceolaris.
Order IV. SCIRTOPODA.
Fig. VII. Pedalion mirum.

' See pages 30, 31, 32.

see et
ew

F Front view
S dStde view

Ciliary wreath

pu. prinetpal wreath

dw Secondary wreath
dp dtyligerows prominences
bf. buceal funnel
te trophe

foot

en

* * In all cases throughout the plates, where the sex is not mentioned, the animal

Floseularia campanulata

” ”
Floscularia ambigua

” ”
Floscularia algicola
Floscularia longicaudata
Floseularia coronetta

”
Floseularia Cyclops
Floscularia cornuta
Floscularia regalis

” ”
Floseularia ornata

a (after Cubitt)

trophi

PLATE I.

as a female.

male,
male,
. female,

young female just hatched ;
the same a little older

side view. 5
obliquely ventral .
same scale as 1 :
enlarged. 6 5
trochal dise from above
side view . 0
obliquely ventral .

side view . 6
dorsal view .

side view . E .
trochal disc, from above
side view : re
side view

side view

dorsal view .

obliquely dorsal .

side view . ; 6
obliquely from above .

CT Hudson ad wv. del

FLOSCULARIA.

2.F, AMBIGUA.

5.F.CORONETTIA. 6.F.CYCLOPS.

1.F.CAMPANULATA.

3.F. ALGICOLA .
7.¥.CORNUTA. 8.F REGALIS

6. Floscularia trilobata . ; 5 . dorsal view
6a. = 3 F A 5 . ventral view .

PLATE II.

1. Floscularia algicola . . : . a cluster. . H

la. iy 5s , 6 c . side view of head 1eL

1b. 3 Ps 5 F - . dorsal view of head H

2. Floseularia coronetta 0 0 . dorsal view of head . ist

3. Floscularia campanulata (? ambigua) diagram after Dr. Moxon

4. Diagram ofa Floscule . 9 6 2 H

5. Floscularia Hoodii . <3 . side view ° H

5a. a 3 ventral view . : ‘ é q 1BE
H
1s

“WLV@OTIML'S9 ‘“IGOOH 4's
-TTNOSOTA VAO WVEDVIA + ‘) VLV TONVdWVO TG “WLIESNOWOO 72 “UONIN VODIGNV AL
“VIHVINISOTH# * [mp ATA pe’ vospryzy 4

NS

\
\

\

IN

{il

|

i

|

yy
7

——~

1. Floscularia mira
2. Floscularia mutabilis
2a. ” ” cl

2b. Phe , bh)
2c. ” ”
3. Floscularia calva
3a. ” +h)
3b. a 7

PLATE III.

seen obliquely from above
side view ; swimming

side view ; at rest

young female, ventral view
young male, side view

side view . 0

young female, dorsal view (after Mr. J. Hood) .

young male, side view (after Mr. J. Hood)

Fo ot ot bt

7 .

MM Ve

VIVINACH AY .

VMIVG he ecPilavi nn ff ¢
"VIUMVTNISOTA

“Van at

ep AKA pe uospny 9

7. _— ~~ ee

® 7 i
are
PEATE LV;
1. Stephanoceros Eichhornii, side view . a eh
8. Young female just hatched, adhering to the elas coyer Arend feels G
9 & 10. the same a little later... G
11, 12, & 13. 3, 8, and 11 hours after ihe reatehedts G
14 & 15. 18 and 36 hours after being hatched . G

Details of Stephanoceros Hichhornii.

2. Head, dorsal view.

3. 4, ventral view

4. ,, side view

5. 4, seen dorsally in ie plane >ssing through We nob of AG ciliary
wreath . 0

HH Ae

>

Trophi . :

. Ovary (after Dr. Taydie)

16. A budding tentacle (after Mr. Rossiter)

17, The same a little more developed (after Mr. Rossiter)

a)

| IINNYOHHOIT S
"SOUAIONVHAALS

osson Hd ‘G1°79 sour
pf

dua: queyrep

aes = | EEE

2
eS
A

PLATE V.
1. Melicerta ringens . A . ventral view . : z A A 5 lat
la. p 7 4 F . side view . F H
10. 3 x : 4 . partially retracted, de view . % 5 leh
lee y z E - upper part of 10, enlarged 5 : o ash
1d. oy *) ; ‘ . young female, side view . 3 a EL
le. % = 3 3 . cluster. Bees
If. R 5 . trophi 3 Jal
2. Melicerta conifera . : - ventral view 5 JEL
2a. . * ‘ e . dorsal view go ial
2b. 5 o : Fi . side view . F F - isl
Qe. $ 4 5 5 . details of head, SS view . 5 .
2d. ne 3 : a . details of body, ventral view q del
2e. 55 yp ; ; : longitudinal muscles to chin and meek H
3. Melicerta tubicolaria . . ventral view 5 . F ~
3a. ” 5 = sidemiews. , ist
3b. a “ 5 5 - young female, aeesall view 5 iel
3c. 6 .* young male, side view 5 yee
4. Desa one a Melicerta 5 3 ; 3 3 5 5 F 5 S oi5l

-WLUAolTIW yVio WVUDVIA'F ‘VIUVTIODIGNI Ne WHYAAINOD W2 SNAONIA WL
“VEULIITAWN : es Avie, *

Fi \ RZ ald will

LG slips 18s SRD aH Boies i

~FLOSCULARIADA:.

Difficultates, quibus laborat investigatio animaleulorum microscopicorum, in-
numer; eorundemque certa et distineta determinatio tantum temporis, tantum
oculorum judiciique acumen, tantamque animi compositi et patientissimi presentiam
requirunt, ut vix alind supra. Nihil facilins quam animalcula videre, eorumque
motu et ludo delectari; differentias vero in bestiolis simplicissimis, mobilissimis,
mutabilibus, in area minimi campi conspectum omni momento effugientibus, per-
cipere, perceptas variosque cujusvis motus verbis significantibus exprimere, hic
labor, hoe opus.

Hine spe post lucubrationem plurium horarum, eum yidere et mirari lassus
essem, defectu tamen verborum insolitos motus et imagines exprimentium, metu-
que, ne qui ipse quidem oculo et mente percepi lectori obscura manerent, chart
nihil commisi.—O, F. MULLER.

CHAPTER V.

Order I. RHIZOTA.

Fixed when adult, usually inhabiting a gelatinous tube excreted from the skin;
foot transversely wrinkled, not retractile within the body, ending in an adhesive disk or
cup.

Family I. FLOSCULARIADA.

Corona produced longitudinally into setigerous lobes ; buceal orifice central ; ciliary
wreath a single half circle above the buccal orifice ; trophi wncinate.

This family, like the one that follows it, contains some of the largest, handsomest,
and most attractive of the Rotifera. It consists of only two genera, Floscularia, and
Stephanoceros, which closely resemble each other in their habits and internal structure,
but differ considerably in outward form. The latter genus, which is represented by
only a single species, has its frontal lobes produced into long arms, having setie set
round them in whorls; while the former, which contains no fewer than sixteen species,
has the lobes comparatively short and expanded, with the sete radiating from their
summits, and frequently edging the whole rim of the corona. The two genera differ
also in the kind of tubes that they secrete. The majority of the Floscules have some
what irregular tubes of slight consistency ; but Stephanoceros has a thicker tube, more
regular in shape, and apparently of greater density.

Both genera are to be found adhering to the common water-plants, frequently in the
axils of the leaves; though some species prefer more exposed positions on the stems, or
on the leaves themselves. The Flosculariade bear captivity fairly well, and may be
easily bred, provided that they have a good-sized trough and a plentiful supply of food ;
for they are greedy feeders. They live mainly on Monads, ciliated Protozoa, &e.; but
occasionally capture and swallow comparatively large animals, such as Stentors, or even
free swimming Lotifera. In one respect, however, captivity often tells on them; for
the home-bred specimens, though healthy enough, and breeding freely, are frequently
much inferior in size to those that are brought fresh from their native haunts.

Genus FLOSCULARIA, Oken.

Generic CHaracters.—Frontal lobes short, expanded, or wholly wanting ; sete
very long and radiating, or short and cilia-like; foot terminated by a non-retractile
peduncle, ending in an adhesive disk.

Neither pen nor pencil can do justice to the beauty of these animated flowers. It
can only be properly appreciated when they are seen by dark-field illumination under
the microscope. Then the eye is at once delighted with the filmy transparency of the
petaloid head, with the flowing curves of the lobes, and with the pencils of delicate sete
radiating from their summits in all directions, and often passing altogether out of the
field of view. Should, moreover, the species under observation happen to be a social
one, such as F’. campanulata, four or five specimens may often be found with their

44 THE ROTIFERA.

tubes in juxtaposition, and the whole group can then be well shown under a low power;
the animals, in various positions and under different aspects, forming, with their delicate
cases and interlacing set, a picture that can be hardly rivalled.

fF. campanulata, when fully expanded, has been compared to “a long tubular flower
with a five-angled petal, the tube swollen, contracted below the lip, and seated on the
end of a long stalk.” ! This description applies very well in most respects to the other
species, except that the number of petals is not always five ; for, owing to late discoveries,
there is now a regular series of Floscules with seven, five, three, and two lobes; and
one species in which the corona is not divided into lobes at all.

The setie also, which crown the lobes, and are so highly characteristic of the better-
known forms, vary quite as much in the newer species as do the coronre; in some
exceeding the Rotiferon’s utmost length, and in others diminishing almost to the size of
ordinary cilia. Indeed, if the strange genus Acyclus—which must be very closely allied
to the Floscules—be also taken into account, as well as the equally curious genus
Apsilus, there is a tolerably complete series of forms showing a gradual change from a
Floscule, with seven lobes, and long radiating set, to a Floscule-like Rotiferon in which
the setw have entirely vanished, the corona has degenerated into a very delicate
protrusile cup, and even the foot itself has shrunk into a mere sucking disk.

The Tube. —The Floscules inhabit a semi-transparent gelatinous tube, into which
the animal when alarmed can contract itself with great swiftness. It is secreted by the
creature itself, and moulded on its own body by its sudden contractions, and slow
expansions. When free from diatoms and extraneous particles (which is seldom the
case), it is difficult to be seen, especially by transmitted light: under the dark-field
illumination, not only can its outline be seen, but the substance of which it is composed
can be traced from the outer surface, far in towards the Rotiferon itself. The tube
becomes thinner towards the top, and it is often difficult to trace it there ; but it will
generally be found to close in neatly a little under the neck.”

A Floscule, emerging from its tube, after one of its contractions, presents the appear-
ance of a pear-shaped body on a transversely wrinkled stalk, with a pencil of long
parallel hairs rising from the puckered centre of the rounded upper end. It slowly
stretches itself till the wrinkles of the foot have nearly disappeared ; and then, after a
delay, sometimes provokingly long, the puckers round the sete relax, and the whole pencil
is thrust forward, by the unfolding of the lobes of the corona ; which, as they rise, show
that they had been drawn down into the body by inversion, as the tip of the finger of a
glove may be drawn into it, by pulling it from within. After a little further hesitation,
the lobes unfold, and expand into a wide cup, while ‘‘ the setz seem to fall round it on all
sides in a graceful shower.” The now fully expanded Floscule consists of five well-
marked portions ; the corona, the vestibule, the crop, the trunk (including the viscera),
and the foot.

The corona is a delicate nearly hemispherical cup, whose free edge is cut into
lobes varying much in size, shape, and number. There are two main varieties of lobe ;
in the one they are narrow, pointed, and ending in a spherical knob; in the other they
are broad, bounded by low convex curves, and knobless. In almost all, the dorsal lobe
is conspicuous by its greater size, or peculiar appendages. The corona is furled by the
action of delicate muscular threads imbedded in its surface, and expanded by the upward
rush of fluid between its outer and inner integuments, due to the contraction of the
transverse muscles of the trunk.

The sete are set either on the knobs that crown the summits of the icbes, or on a
thick rim ruming round them; and they sometimes form a continuous fringe on the

! Gosse, Popular Sci. Rev. vol. 1. 1862, p. 160.

2 Though the tube is of the flimsiest material, and lighter than water, it certainly protects the
animal from its enemies. I have watched a sharp-jawed larva trying to bite through a Floscule’s tube,
and it was as completely foiled by its swaying about from side to side at every touch, as a boy at Hallow
E’en is bafiled by a floating apple, when trying to seize it with his teeth.

FLOSCULARIADAL. 45

rim of the corona. Owing to their great delicacy, and to their lying in different planes,
it is impossible to see nearly all of them at once. They vary greatly in size, position
and arrangement; but their varieties, with those of the forms of the lobes, will be
described in the account of each species.

Volwocina, small Infusoria, and floating particles may constantly be seen to enter the
bell-shaped corona, and to pass thence down towards the buccal orifice. The sete take
no part in this process, beyond that of preventing the return of the captured prey, by
interlacing in a close network over the top of the cup, or by individually lashing at a
returning object, so as to throw it back again into the gulf. The interlacing of the set
is accomplished by the heads of the lobes approaching each other, and, should the prey
be large and vigorous, the lobes are pressed tightly together, so as to completely bar
all chance of escape. In most of the species, the motion of the sets appears due to the
fitful action of the cuticle, on which they are placed; but in F. trilobata, F'. Hoodit,
and notably in £'. mutabilis, a regular cilia-like motion occurs in the sete ; while in
I’, mira there is a still wider departure from the ordinary type; since in this Floscule
each seta has a constant, slow, independent, amceboid motion.

The Vestibule.—At the bottom of the corona is a second chamber (the vestibule),
bounded above by a highly contractile collar, below by a diaphragm with a slit in its
centre (the buccal orifice), and on the sides by thick walls. On the upper margin of the
collar, and running half round it on the ventral side, is a horse-shoe-shaped ciliated rim,
ending in two knobs, bearing long, slowly moving cilia; and this rim is so set, that it
slopes downwards from the dorsal side to the ventral. This true rotatory apparatus
may be easily seen in the large Floscules #’, Hoodii and I’, trilobata.!

A current, due to the action of these cilia, sets down the coronal cup, in a plane at
right angles to its base, and carries the food, past the collar, into the vestibule. When
once an organism has reached the vestibule, there is no return for it to the upper world.
The Floseule often suffers two or three small Jnfusoria &e. to wander about round
the walls of the vestibule ; but at any attempt to pass the collar, that at once contracts
on itself, and closes the passage. In the diaphragm, which is the base of the vestibule,
there is a long slit, the buccal orifice, bounded by two chitinous lips (PI. I. fig. 1d, lp),
from which there hangs into the next chamber, called the ‘‘ crop,” an elastic tube (PI. II.
fig. 4, ¢), which may be seeu always undulating above the mastax. When there are
victims enough collected in the vestibule to make it worth while to swallow them, the
collar contracts violently, the lips dart forward with a sort of snap, and the prey is
forced down the tube into the crop. It is evident that this hanging tube is an admir-
able contrivance for admitting fresh prey into the crop, while at the same time pre-
venting the return of that previously captured. Naturalists plagiarise from the Floscules,
when they drop their live specimens through a quill stuck into the cork of a bottle ;
only the rigid quill is far inferior to the flexible and ever-moving tube.

The erop (Pl. Il. fig. 4, ep) is a rounded chamber just under the diaphragm at
the base of the vestibule. It has very thick walls, which are strengthened externally
by two granular spots one on either side of the Floscule’s shoulders (PI. I. figs. 4, 8a).
Viewed as opaque objects they are white, like the similar oval knobs on Megalotrocha
alboflavicans.

Under the action of small muscular fibres, the sides of the crop contract alternately,
and throw the contained food from side to side ; by which means every part of it in turn
is subjected to the action of the jaws (Pl. II. fig. 4, tz). These lie at the bottom of the

1 Dr. Dobie described the two ciliated knobs in F’. cwmpanulata, Ann. Nat. Hist. 1849. Mr. Gosse
inferred the existence and position of the true rotatory organ from the motion of particles in the
coronal cup (Tenby, p. 307). Dr. Moxon says that ‘‘ the alimentary canal above the gizzard is divided
by a highly irritable cilium-clothed sphincter of irregular outline” (Zrans. Linn. Soc. vol. xxiy. 1864,
p. 457). In 1867 I published a full description of the rotatory organ of EF’. campanulata in the Trans.
Bristol Micr. Soc. In 1869 Mr. Cubitt did the same for Stephanoceros and I’. coronetta (Mon. Micr.
J. vol. ii. 1869, p. 133).

46 THE ROTIFERA.

crop, attached to the walls of the stomach; aud to reach the latter everything must pass
between them. ‘The Floscules are great feeders, and sometimes the crop becomes so
distended with food, that the animal, unable to force it past the jaws quickly enough,
seeks relief by expelling the contents of the crop right through the inverted tube. The
lobes of the corona are folded back on the body, the diaphragm is pushed upwards and
the tube is thrust mside out through the slit in the diaphragm; while through it pours
the unmanageable food. Dr. Moxon (loc. cit.) has seen this take place on two separate
occasions, and I have seen it once: im each case the animal was F’. campanulata.!
The appearances due to the tube have been variously described as caused by moving
filaments, lamin, vibratile cilia, and a waving membrane; but these observaticns of
Dr. Moxon, confirmed by my own, put the matter beyond doubt.

The Trunk.—The outer wall of the trunk is a tough, elastic, and often shining
cuticle, which has an inner and softer layer of varying thickness. This double covering
interferes greatly with a clear view of the viscera, especially as it has tercommunicating
cayities and channels containing fluid, which is driven upwards and downwards by the
contraction of the muscles, and by the various motions of the body. Nor is this all; for
the fluid itself is often rendered semiopaque by granules floating in it. It is doubtless by
means of this fluid that the lobes of the furled corona are pushed forward and expanded,
the transverse muscles of the trunk forcing it into definite channels, which are thus
rendered tight and stiff, hke the ribs of an umbrella. My. Gosse? has deseribed and
figured these in the case of #’. ornata; and has noticed how the granules flow from the
trunk over the neck into the various channels of the coronal cup. Mr. Hood, too, has
watched a steady stream of granules passing down from the trunk into the foot, and
returning again from a point about half way from its extremity. The granules may be
frequently seen, in some degree, in specimens of almost every species, but occasionally
they are in such abundance as to render the animal quite opaque; and, by reflected
light, of a dead white.

The foot is very long and flexible, and is capable of great expansion and contraction,
but cannot be drawn into the trunk. It consists of little else but muscles. The great
longitudinal muscles pass down its whole length, and numerous fine muscular fibres
encircle it everywhere, covering it with transverse rings of very variable thickness, from
its junction with the trunk to its extremity. This latter contracts to an inextensible,
and usually short cord or peduncle, which itself terminates in a sort of disk. In the foot
are also the two club-shaped glands (so common in other genera) which probably secrete
a viscous fluid for fastening the disk to some extraneous object.

The Nutritive System.— The food is feebly pecked at by the jaws, while it is in the crop,
but it evidently undergoes there some process of digestion. I once saw a Floscule bolt a
small Salpina. When inside the crop it was still alive, and it charged from side to
side, in the vain hope of escape. The sharp points of its lorica ought to have made its
captor uncomfortable ; but the only result was, that its outline gradually grew dim, and
that before long the whole animal faded into a shapeless mass.

Mr. Gosse® notices the absence of the mastax, and says of the trophi that ‘‘ the jaws
consist of a pair of curved unjointed but free mallei, with a membranous process beneath
each. Each malleus (PI. I. figs. 9a, 9b) is an unecus of two slender arched divergent
fingers, united by a subtle web; the back of each curves downwards, where, expanding
and becoming membranous, it is connected with some delicate but definite processes with
rounded outlines, which I should have supposed to be muscular bulbs, but that they
remain after treatment with potash.”

After passing between the jaws the food enters the stomach (PI. II. fig. 4, s) appar-
ently directly, as no esophagus is visible. The alimentary canal is divided into stomach (s)
intestine (i), and rectum (r), which latter is bent on itself, and ascends to the cloaca (cl)

| Fig. 1, Pl. D, is a copy of Dr. Moxon’s drawing, showing the tube turned inside out and pro-
4yuded through the slit in the diaphragm : the lobes (J) are shown drawn down close to the body.
2 Popular Sct. Rev. yol. i. 1862, p. 160, pl. ix. 3 Phil. Trans. 1856, p. 419.

FLOSCULARIAD AS. 47

on the dorsal surface. A partial separation (probably due to a sphineter muscle) is
usually visible between the stomach and intestine, and the distinction is often made
more obvious by the different colour of the contained food. The whole alimentary
tract is richly ciliated; and so is the tube (¢) that hangs down into the crop. The cilia
can be easily seen in the intestine, when it is partially empty; and on the tube, when it is
eyerted by the Floscule’s disgorging its crop.

Secreting System.—In the great majority of Rotifera there are two gastric glands,
seated on the top of the stomach. I have, however, never been able to detect them in any
Floscule, neither has anyone recorded their existence except Ehrenberg and Grenacher.
The latter describes and figures them of unusual length in F’. campanulata,' but it is
probable that in this matter he is mistaken. He also describes two club-shaped glands
in the foot.

Vascular System.—It is very difficult to trace this in most of the Floscules, owing to
the optical difficulties due to their skins. But in 1864 Dr. Moxon (loc. cit.) published
a complete account of it in £. campanulata. His figure of the contractile vesicle
(Pl. II. fig. 8, cv), the lateral canals (/c), and of four of the vibratile tags (vt), is so clear
as to render any verbal description unnecessary. A fifth vibratile tag was discovered
by-Grenacher in F’. campanulata (loc. cit.), in the side of the coronal cup, near the
spot where Dr. Moxon (Joc. cit.) had anticipated that it would, some day, be found.
Parts of this system have been seen in several other species, and doubtless it exists
in all.?

The muscles consist of non-striated fibres. Below the bottom of each depression,
between the lobes, a muscle runs downwards in the substance of the coronal cup and
vestibule, and is lost on the surface of the body, to reappear again, as it nears and passes
down the foot. The anterior portions of these muscles end in two or more branches
which diverge to the thickened rim of the coronal cup, and often interlace, as seen in
F. coronetta (Pl. II. fig. 2), and in F. trilobata (Pl. II. fig. 6), where they may be
seen reaching the summit of the dorsal lobe. There are some half-dozen transverse
muscles imbedded in the integument of the trunk; and the walls of the vestibule, with its
upper ciliated rim, are all highly contractile.

The Nervous System.—Dr. Moxon (Joc. cit.) has described and figured the nervous
ganglion in #. campanulata, and I have seenit in F’. Hoodii. It is in nearly the same
position as it is in Stephanoceros, namely, on the dorsal side of the vestibule ; and is, as
usual, close to the organ of taste, and not far from the eyes and dorsal antenna; to all
of which doubtless it sends out nervous threads. Dr. Moxon has seen and figured such
threads in F’. eampanulata (P1. I. fig. 8, 7.)

In the great majority of the Rotifera the mastax is also not far from the nervous
ganglion ; but in the Flosculariade the mastax almost vanishes, while the jaws and
ganglion are far apart.

Organs of Sense.—T wo red eye-spots lie usually above the ganglion; but, as in the
adults they are deeply imbedded in the integument, they are not easily seen. In fact the
ordinary way of attempting to see them, by transmitted light, will scarcely ever be
successful; but by treating the Rotiferon as an opaque object, and concentrating a
strone light on it, the eyes may often be seen glowmg like rubies when all else is
invisible.* The eyes are conspicuous in the half-grown animals, and in the young within

' Sieb. wu. Koll. Zeits. Bd. xix. 1869, p. 483.

2 Dr. Leydig saw the contractile vesicle in F’. cornuta ; Ueb.d. Bare d. Réderth. 1854. Dr. Bartsch
has seen the contractile vesicle, lateral canals, and vibratile tags in his F’. longilobata (F’. coronetta)
Rot. Hungaria, 1877.

$ Mr. Gosse (Popular Sci. Rev. vol. i. 1862, p. 166) observed one eye at a time in F. cornuta. Mr.
Cubitt (Mon. Micr. J. vol. iii. 1870, p. 245) saw the eyes in F’. coronetta; and I have recorded (J. Roy.
Mier. Soc. 2 Ser. vol. iii, 1883, p. 163) my having observed them in F’, Hoodii and I’. regalis. Herr
K. Eckstein (Sieb. w. Koll. Zeits. Bd. xxxix. 1883, p. 347), unaware of the above observations, says
‘the Floscules have been hitherto regarded as eyeless,’’ and records his having seen the eyes in F.
cornuta.

48 THE ROTIFERA.

the eeg. Thereare three antenne in J’. campanulata, I’. coronetta, and Ff’. Hoodii; and
no doubt the same three may with care be found in the other species. There is one on each
side of the neck, and one on the median line near the middle of the dorsal lobe. The two
lateral antenne are very short tube-like prominences each carrying a brush of divergent
sets ; they are very apparent in F’. coronetta (Pl. II. fig. 2): the dorsal antenna is a
mere setigerous pimple.! The sete on the lobes act also as organs of touch, warning the
creature of the approach of anything detrimental to its delicate cup; and whipping
back into it any animalcule that endeavours to escape from it.

On the middle of the contractile collar, which is above the vestibule, and on the dorsal
side of it, there is a round projection facing the concavity of the cilary wreath. It can
be easily seen in F’. coronetia and F’. Hoodii, and is probably an organ of taste, as it is
constantly thrust forward to meet any particle which is passing into the vestibule. A
very obvious and tongue-like organ holds a similar position, and acts in a similar way, in
Stephanoceros.

The Reproductive System.—The ovary, with its clear spherical germs, and frequently
with an opaque egg in it, can be seen filling the greater part of the space between the
stomach and the ventral surface. No other portion of the apparatus has been made out,
owing no doubt to a habit that the Floscules have of contracting themselves sharply into
their tube when about to lay an egg. When laid, the eggs are ranged above one
another, between the foot and the tube. The ordinary number of female eggs is from
two to five; though as many as eight or ten have been seen at once. The male eggs,
which are smaller, rounder, and more numerous, than the female, frequently amount to
as many as nine or ten, and have occasionally been seen in a cluster of eighteen or twenty
in the same tube. Doth are inclosed in a delicate shell, which is left behind in the tube,
when the young Floscule is hatched. Dr. Weisse and Mr. Hood agree in assigning six
or seyen days as the time from the extrusion of the egg to the birth of the young
animal.

The Young Female.—‘ The infant female Floscule is a white cylindrical maggot
(Pl. 1. fig. 9¢), blunt at the front end, with a central orifice, whence protrudes a short
brush of cilia ; but the margins are capable of unfolding, when the cilia are seen to form
a whorl around the truncate summit, swiftly rotating. The margin soon begins to bud
forth the little knobs around which the cilia are gathered (Pl. I. fig. 9d); these
quickly increase in length, and the angular flower-like corona gradually forms.
Meanwhile the little creature, which was at first free, attaches itself by its hinder end,
and assumes the condition as well as the form of the parent.” ?

Mr. Hood has observed in Ff’. calva, that the young animal fixes itself two or three
hours after it has burst its shell, and soon begins to form its tube, which at first rises
barely to half the height of the foot. By the time it is three days old (PI. III. fig. 3a)
the tube has attained fair proportions.

The same observer noticed that the lobes of the young F. ambigua began to
develop from a collar under the ciliary wreath, and were at first merely a dorsal and
ventral lobe ; the latter with a small notch. In three or four days the notch deepened
and widened so that there were three lobes; but it was not till the fifth or sixth day that
the rudiments of the small side lobes (the fourth and fifth) made their appearance. The
young Floscule arrived at maturity at the twenty-fourth or twenty-sixth day, but continued
to increase in size after it had deposited eggs: in fact, did not cease to grow till shortly
before its death. The whole lifetime, in a trough, was from forty to forty-six days.

Captivity, however, affected the growth of the animals, even when carefully attended
to, and plentifully supplied with food. On one oceasion, for instance, a large
EF’. campanulata 4!; inch long, from one of the Scotch lochs, was placed in a tank; and

1 Dr. Moxon (loc. cit.) first called attention to their existence in the Floscules. Herr Grenacher
(loc. cit.) mentions his having discovered the median antenna in F’. proboscidea (F'. campanulata) ; but
was unaware that Dr. Moxon had seen and described all three, five years before,

2 Mr. Gosse on F’. campanulata. Popular Sci. Rev. vol. i. 1862, p. 166.

FLOSCULARIADE. 49

the young reared from its eggs, though perfectly healthy and breeding freely, never
exceeded 5!, inch in length : their eggs, too, were half the size of those of their parent.

In £. trilobata, occasionally, the egg produces the living young in the body
of the parent. Mr. Hood has seen the embryo alive in the egg, within the Floscule,
and has witnessed its birth: yet Dr. Collins has seen the same Rotiferon deposit the
usual eggs in its tube.

The Male.— Until 1874 no male had been discovered among the Rhizota ;' and indeed
some observers supposed this group to be monecious ; but in that year I had the good
fortune to find the male of Lacinularia socialis, and to study it thoroughly. Soon
afterwards I found that of Floscwlaria campanulata (Pl. I. fig. 1c) and I have since
seen what I believe to be the male of F'. mutabilis (Pl. IIL. fig. 2c). Mr. Hood has
observed and figured the male of /. calva (Pl. IIL. fig. 35), and has seen that of
FI’. ambigua actually hatched. The structure of the male Floscule has not yet been
thoroughly investigated ; but, so far as it has been studied, it has been found to agree
with that of other male Rotifera. The corona is an imperforate many-lobed cushion,
surrounded by a simple eirclet of long cilia. The nutritive system is wholly absent.
Two red eyes are visible just under the surface of the corona; and the longitudinal
muscles, for withdrawing the head, are generally obvious. Nearly the whole of the
body-cavity is filled with a large sperm-sac (PI. I. fig. 1c, and Pl: IIL. fig. 8b; ss) from
which the penis (p), a ciliated protrusile tube, proceeds to the dorsal surface, at the
junction of the trunk and foot.

The vascular system, ganglion, and antenne have not yet been seen; but no doubt
they are present, as in the males of other Rotifera.

FI. recauis, Hadson.
(PIS Taties8°)

Floscularia regalis ‘ : Hudson, J. Roy. Micr. Soc. 2 Ser. vol. iii. 1883, p. 166, pl. iv. fig. 3.

SP. CH. Lobes seven, knobbed.

The corona is a deep cup with a nearly circular rim, from which project four knobbed
triangular processes on the ventral side, dividing that half of the rim into three equal
spaces. The processes curve slightly outwards; and, at the rim, their bases unite, so
as to give that edge of the cup a semi-hexagonal appearance. In the middle of the
dorsal side of the rim rises a large triangular knobbed lobe, bearing on each side a short
recurved knobbed process. All seven knobs carry pencils of long radiating sete. A
true ciliary wreath at the bottom of the trochal cup, and two red eyes, can be easily
seen. This remarkable Rotiferon, the only seven-lobed species, was found by Mr. Thos.
Bolton in September 1882, near Birmingham.

Length, ,1, to ;4, inch. Habitat. Lakes and clear ponds. Birmingham (T'.B.‘);
Perth (J.H.,4 and W. Dingwall) : not common.

F. coronetta, Cubiit.

(PLI. fig. 5; Pl. IL fig. 2.)

Floscularia coronetta : : : Cubitt, Mon. Micr. J. vol. ii. 1869, p. 133, pl. xxv.
Stephanoceros Horatii - z c Cubitt, Mon. Micr. J. vol. vi. 1871, p. 166.
Floscularia longilobata . 5 : Bartsch, Rot. Hungaria, 1877, p. 24, ii. Tab. fig. 14.

" Mr. Gosse (Joc. cit. p. 487) described some probably male eggs in M. ringens.
* Mon. Micr. J. vol. xiii. 1875, p. 45.
* As the Rotifera vary from } to =4; inch, no attempt has been made to draw them to a fixed scale.
The actual length of each species will be given at the end of its description.
* Throughout the work the following initials will be used in the Habitat :—J. H.=Mr. John Hood ;
T. B.=Mr. Thos. Bolton; P. H. G.=Mr. Gosse; C. T. H.=Dr. Hudson.
BF

50 THE ROTIFERA.

SP. CH. Lobes five, linear, knobbed ; sete, non-extensile.

The corona has five long narrow knobbed lobes, nearly all of equal length, sepa-
rated by deep depressions, and forming a miniature coronet. The dorsal lobe is slightly
the longest, and the lobes are so set on the front of the body that a plane touching the
knobs would be oblique to its longitudinal axis; the dorsal lobe being the furthest
forward. All the knobs carry long radiating sete, and the set are continued all along
the edge of the trochal cup (Pl. IL. fig. 2). The true ciliary wreath and the eyes have
been seen in the adult by Cubitt (doc. cit.) ; but the former with difficulty. The lateral
antenne can be readily seen when the animal is favourably placed, as well as the delicate
muscular threads by which the longitudinal muscles act on the corona (PI. IL. fig. 2).
As many as seven male eges have been seen in one tube.

Length, |. inch. Habitat. In ponds and marsh pools ; rare. Wandsworth Common
(Cubitt); Forfar, Fife (J.H.).

F. mrra, Hudson.
(PLP Tihs fies 1)
Floscularia mira ; £ dj 5 Hudson, J. Roy. Micr. Soc. 2 Ser. vol. v. 1885, p. 609.

SP. CH. Lobes five, linear, knobbed ; sete extensile.

The corona is very like that of J’. ornata, which species the Rotiferon closely resembles
in every respect but two. First, the tube is much more like that of a Stephanoceros than
that of an ordinary Floscule. I have seen only one specimen, but Mr. Cocks (its dis-
coverer) tells me that the tubes of the half-dozen specimens which he has seen were
all of the same sort. Secondly, in its sete F’. mira isnot only unlike all other Floscules,
but is unique among the Rotifera: for each seta is in constant independent motion,
slowly extending or contracting like the pseudopodium of an Amcba. When the
retracted seta begins to extend again, it is often bent into a whip-like shape, a wave
of motion overtaking, as it were, the resting anterior portion, and finally driving out
the latter with a characteristic flourish of its tip. The sete are of amazing length and
abundance, exceeding the total length of the Rotiferon. This very rare and wonderful
creature was discovered by Mr. W. G. Cocks in June 1884.

Length, 4, inch. Habitat. Unknown; found in an aquarium, in water that probably
came from Epping Forest or Walton-on-Thames (W. G. Cocks).

F. ornata, Hhrenberg.
(Pl. I. fig. 9.)
Floscularia ornata.—Ehrenberg, Die Infus. 1838, p. 408, Taf. xlvi. fig. 2.

. i Peltier, Ann. Sci. Nat. Zool. 2 Sér. t. x. 1838, p. 41, pl. iv.

i FA Dujardin, Hist. Nat. Zooph. 1841, p. 610, pl. xix. fig. 7.

; Ay Gosse, Tenby, 1856, p. 307, pl. xx.

3 ce » Popular Sci. Rev. vol. i. 1862, p. 160, pl. ix. figs. 1-3.

+ Pritchard, Infusoria, 1861, p. 675, pl. xxxii. figs. 384, 385, and xl. figs. 25, 26.
a =; Weisse, Sieb. u. Kbll. Zeits. Bd. xiv. 1864, p. 107, Taf. xiv. figs. 1-5,

3 5 Bartsch, Die Rdderth. b. Tiibingen, 1870, p. 24.

SP. CH. Lobes five, triangular, knobbed ; dorsal lobe without any process.

The corona has five knobbed lobes of moderate length separated by broad depressions,
the dorsal lobe being distinctly the longest and broadest, and the knobs crowned with
long radiating sete. Ehrenberg describes ’. ornata as haying usually six lobes, but
sometimes five, and draws an example of each case. No doubt it must have been a
difficult matter for one of the old observers with only a monocular microscope, and that
a poor one, to make out the shape of a delicately transparent and scolloped cup, pre-

FLOSCULARIAD i. 51

sented to him so that its upper and under surfaces were projected on each other. With
a modern binocular and dark-field illumination, no tyro would fail to describe correctly
the cup with its five knobbed lobes. Ehrenberg credits this species with two ‘‘clear
spaces’’ that he considers to be gastric glands. I have made frequent search for such
glands, but cannot find them; Ehrenberg’s ‘‘clear spaces” are probably the small
bulbs, the rudiments of a mastax, in which the jaws are inserted.

It is most probably Hichhorn’s ‘‘ Der Fiinger”’ (Pl. B, figs. 15, 16), and, if so, it is
the earliest known Floseule, haying been discovered as long ago as 1767. Unluckily,
Hichhorn has given two other drawings of it, one with nine, and one with ten knobbed
lobes; but, as he complains of the difficulty of rightly understanding and drawing it,
it is possible that these numerous lobes represent only the puckers of the half-expanded
corona. This is a very pretty species, and, as Hichhorn well says, ‘‘no lightning
can dart out of the clouds through the air more swiftly”? than this little animal can
contract upon its prey. Owing to its small size, however, and its lack of transparency,
it is not well adapted for the investigation of the internal organs of the Floscules.

Length. From ,\, to ,\ inch; average ,4;. Habitat. Fresh waters everywhere

F. cornuta, Dobie.
(RIES owi)

Floscularia cornuta ; j , Dobie, Ann. Nat. Hist. 2 Ser. vol. iv. 1849, p. 233, with pl.
” ” . 5 : Gosse, Popular Sci. Rev. vol. i. 1862, p. 168, pl. ix. fig. 6.
ny 3 ; < d’Udekem, L’ Institut, t. xix. 1851, p. 222.
Floscularia appendiculata . 0 Leydig, Ueb. d. Bau d. Réderth. 1854, p. 3, Taf. i. fig. 6.
Floscularia cornuta 5 0 ; Pritchard, Infusoria, 1861, p. 676, with fig.
” a c ‘ 5 Cubitt, Mon. Micr. J. vol. v. 1871, p. 170, pl. Ixxxi. fig. 7.
Floscularia appendiculata . : Bartsch, Rot. Hungaria, 1877, p. 24, Tab. ii. fig. 19.
” of 9 9 Eckstein, Sich. wu. Koll. Zetts. Bd. xxxix. 1883, p. 344,
Taf. xxiii. figs. 1-4.

SP. CH. Lobes five, triangular knobbed ; dorsal lobe with flexible process.

This species was first described by Dr. Dobie (loc. cit.) and was afterwards re-named
as a new species by Dr. Leydig (loc. cit.). It is like F. ornata, but possesses at the
back of the dorsal lobe a curious flexible process, which is probably an organ of touch,
though it does not appear to bear set, or to have any opening. It rises from a swollen
base just below the knob, and is suddenly bent over the latter, and then turned up again
so as to point forwards and clear the knob. It occasionally moves a little, and slowly
alters its shape, taking often an undulating form; but it is not moved about like the
antenna of Cephalosiphon or of Rotifer macroceros: it reminds one rather of the slow
bendings of the dorsal appendages of Ff’. Hoodii. The eyes cannot be easily seen in the
adult, but I have succeeded in exhibiting both together by condensing a strong lamp-
light on the dorsal surface.

Leydig (loc. cit.) describes and figures the contractile vesicle but places it away from
the intestine on the ventral side.

Length, cir. 4, inch; Scotch specimens up to j, inch. Habitat. Widely dis-
tributed.

F. cycrtors, Cubitt.
(Pl. I. fig. 6, and Pl. D. fig. 2.)
Floscularia cyclops . 5 : Cubitt, Mon. Micr. J. vol. vi. 1871, p. 83, pl. xciii. figs. 1, 3.
SP. CH. Lobes jive, knobbed, very short, variable in length, but sometimes with the
knobs almost seated on the rim of the coronal cup; the dorsal lobe rather the longest

and stoutest ; sete radiating from the knobs.
r2

or
b

) THE ROTIFERA.

This Floscule greatly resembles I’. ornata, but it is distinguished by its height,!
the length of its foot, and the shortness of its lobes. The fully extended foot is fre-
quently thrice as long as the body. The tube is much wider than usual in proportion to
the animal’s size, and often symmetrical in shape, like that of [. longicaudata. Two
eyes are visible in the adult. This species is prolific and has often many eggs in its tube.
As many as twelve female eggs have been counted in the same tube; and eighteen
male eggs in another. Found by Mr. C. Cubitt in 1871.

Length, ;; inch. Habitat. North Brook, Kent (Cubitt); ponds and marsh pools,
Forfar, Fife (J.H.): rare.

IF’. CAMPANULATA, Dobie.

(PL I. Fig. 1.)

Floscularia proboscidea . : 6 Ehrenberg, Die Infus. 1838, p. 408, Taf. xlvi. fig. 1.
” oH 4 5 z Dujardin, Hist. Nat. Zooph. 1841, p. 610.
Floscularia campanulata 5 . Dobie, Ann. Nat. Hist. 2 Ser. vol. iv. 1849, p. 233, with pl.
” ” 2 : Gosse, Popular Sci. Rev. vol. i. 1862, p. 167, pl. ix. figs. 4, 5.
6 7 ; 5 : Pritchard, Infusoria, 1861, p. 675, with fig.
tD or ‘ 5 , Hudson, Trans. Bristol Micr. Soc. 1867, 2 pls.
Floscularia proboscidea - f Grenacher, Sieb. u. Kéll. Zeits. Bd. xix. 1869, p. 483, with fig.
Floscularia campanulata é é Cubitt, Mon. Mier. J. vol. viii. 1872, p. 5, pl. xxiv. fig. 1.

SP. CH. Lobes five, broad, without knobs, separated by distinct depressions ;
peduncle short ; setee radiating from the summits of the lobes, and fringing the whole
edge of the coronal cup.

I think that Grenacher (loc. cit.) is right in supposing that Dr. Dobie’s F’. cam-
panulata is really Khrenberg’s Ff. proboscidea. Ehrenberg describes the latter as
having six lobes, and also a snout-like organ, of cylindrical form, beset with sete like
those on the lobes, and rising from the depths of the coronal cup above its rim. Gren-
acher suggests, as Dujardin had done before him, that this snout-like organ is only the
dorsal lobe seen before the corona is fwlly expanded. I have thought it best, however,
to retain Dr. Dobie’s name, as J’. canupanulata has certainly neither a proboscis nor
six lobes: I confess, however, that I have little expectation of anyone’s ever finding a
Floscule with either the one or the other.

The sete often appear to be confined to the thickened summits of the lobes, forming
simply a tuft on each. They really, however, fringe the whole circumference of the
corona, sloping further away from it as they approach the bottoms of the depressions
between the lobes, and even at last pointing backwards towards the foot. The vascular
system has been described above, p. 47, and is shown PI. II. fig. 8. Only four vibratile
tags are given in Dr. Moxon’s figure; but Grenacher has seen a fifth, whose position
is shown in Pl. II. fig. 4. A nervous ganglion has been seen by Dr. Moxon. It is
situated dorsally on the neck (PI. I. figs. 3 and 4, gn). Nerve threads are drawn by
Dr. Moxon, as passing from the ganglion to the three antenne. ‘There is one dorsal
antenna, half-way up the coronal cup, and one on each side of the cup close to its junc-
tion with the body (Pl. II. fig. 3, a). They are little more than setigerous pimples.
When the coronal cup is furled, the dorsal antenna may be seen on the summit of the
contracted Floscule’s pear-shaped body. The discovery of the male has been mentioned
above, p. 49. Its sperm-sac (s) and penis (p) are indistinctly shown in Pl. I. fig. 1, c;
but the dead specimen from which I drew the figure was so lately hatched that its
cuticle was more than usually opaque. As many as twenty male ‘eggs have been

! To obtain a correct notion of the completely expanded animal, the foot and case in Pl. I. fig. 6,
should be supposed to be continued quite two inches below the bottom edge of the page on which the
figure is drawn. A small, correctly proportioned figure, is giyen in Pl. D, fig. 2,

ee ee eee

FLOSCULARIADAS, 53

counted! in one tube. This beautiful Rotiferon is by no means shy, but often attaches
itself in closely-packed clusters, of a dozen or more, to the stems or ends of the leaves
of water-plants.

Length. Average about !; inch ; but Mr. Hood has found in the Scotch lochs speci-
mens no less than ,!; inch long. Habitat. Clear ponds and lakes: common.

F, tonaicaupata, Hudson.
(PL. I. fig. 4.)
Floscularia longicaudata . ° Hudson, J. Roy. Micr. Soc. 2 Ser. vol. iii. 1883, p. 165, pl. iv. fig. 2.

SP. CH. Lobes five, rather pointed, without knobs, the dorsal lobe the largest, the
two ventral ones next tn size, and the two lateral ones much the smallest ; peduncle very
long ; sete as in EF’. campanulata.

This Floscule resembles both F. campanulata and Ff’. ambigua but is distinguished
from them by its pointed lobes, very long peduncle, and comparative smallness of its
body. The lateral lobes vary in size in different specimens, and even in the same animal
at different times, and are occasionally as minute as they always are in F’. ambiqua.
The peduncle (pd) is often 4rd of the length of the extended foot, while in other Flos-
cules it varies from 5'sth to \,th of that length. It is a thin, transparent, non-retractile
thread, and is generally thrown into graceful curves and coils. The tubes of all the
specimens which I have seen were remarkably compact and symmetrical.

This is a social Rotiferon, and is to be found sometimes in clusters of a dozen or
more, of various ages and sizes. It selects exposed situations, perching itself on the
edge or point of a leaf, and preferring the convex side to the concave. It is a great
feeder, swallowing small live Infusoria greedily ; and, though not so hardy as I’. ambigua,
yet it will bear being kept ina trough for a fortnight.

F. longicaudata was first discovered by Mr. J. Hood in 1881, on a leaf of Sphagnum
in a poolon Tent’s Muir ; and again in Loch Rea, Blairgowrie, in July and August of the
same year.

Length. From .}; to ,!, inch. Habitat. Lochsand marsh pools ; Forfar, Fife, Perth
(J.H.): rare.

F. ampicua, Hudson.
(Pl. I. fig. 2.)
Floscularia ambigua ? . Hudson, J. Roy. Micr. Soc. 2 Ser. vol. iii. 1883, p. 163, pl. iv. fig. 1.

SP. CH. Lobes apparently three; viz. one large broad dorsal lobe, and two much
smaller ventral ones ; a pair of nunute lateral lobes le between the dorsal and ventral
lobes ; sete, asin EF. campanulata.

This broad stumpy Rotiferon connects the five-lobed with the three-lobed Floscules ;
for though, at first sight, it seems to have but three lobes, there is also a minute lateral
pair. These lateral lobes are frequently reduced to mere thickenings of the rim of the cup,
but can always be detected by the sete radiating from them. From some points of view
F. ambigua closely resembles F'. campanulata; and, indeed, I think that Dr. Moxon (PI.
Il. fig. 3) may have mistaken the one for the other.

From the body up to the dorsal lobe, as in £’, Hoodii, run two ridges of semi-trans-
parent tissue, which look like buttresses to the coronal cup; and form, with it and the
dorsal surface, a deep hollow, at the bottom of which lies the neck.

The animal has a habit of so contracting itself as to throw its cuticle into deep folds,
especially at the neck, and at the base of the body. There often appears also to be a

1 By Mr. W. Dingwall, of Dundee.

o4 THE ROTIFERA.

well-marked separation between the body and foot, the latter looking as if it possessed
only half the width of the body, at the line of junction.

F’. ambigua was discovered by Mr. J. Hood in May 1881 on a leaf of Sphagnum, in a
mossy pool on Tent’s Muir, Fife. Its habits are the reverse of those of F’. longicaudata.
Tt selects for its post the axil of a plant, or the under surface of a leaf, especially of a well-
curled one; so that it is difficult to find a specimen that can be easily studied from
various points of view. Thus placed as it were in ambush, the burly Floscule draws,
with its powerful ciliary wreath, all kinds of organisms into its coronal cup. Nothing
seems to come amiss to it, and its appetite never fails. Mr Hood has seen it devour the
young of (cistes pilula, and of G2. wmbella ; as well as other free swimming Rotifera,
along with all kinds of Infusoria ; so that, to use his own vigorous language, ‘it would eat
its own weight in three hours.’’ The same observer has twice seen the male hatched
from the egg laid in the tube; and noticed the motion of its spermatozoa in the sperm-
sac,

Length. From 3, to ,!, inch. Habitat. Lochs and marsh pools; Forfar, Fife,
Perth (J.H.); near Birmingham (T.B.); Woolston pond (P.H.G.): sometimes abundant.

F. auaicona, Hudson, sp. nov.
(eA i aie tye TEAL IMIG ales 1)

SP. CH. Very small ; corona precisely that of F. ambiqua, but ornamented with dots
arranged in symmetrical patterns ; tube, if present, wndistinguishable.

This pretty little Rotiferon is very like LZ’. ambigua, differing but little from it except
in its ornamented corona, small size, and strange dwelling-place. Its coronal cup is
ornamented on the outside with minute dots, arranged in a symmetrical pattern, as
shown in Pl. II. figs. 1a, 1b. It makes its home in a parasitic growth (Gloiotrichia
pisum') on the stems of water plants. Possibly it may in this way avoid the necessity
of making a tube, as the parasitical sphere that it lives in seems to consist chiefly
of a kind of grey mucus; but I could not be certain whether it had a tube or not: Mr.
Gosse searched with great care, but could see none.

This Rotiferon was found first by Mr. J. Hood in 1882, at Rosemont Loch, Blairgowrie.
It was then very abundant.

Length, ,!; inch. Habitat. Lochs, Perth (J.H.): not common.

By

F. vrimopsata, Collins.
(Pl. IL. fig. 6.)

Floscularia trilobata 6 3 ; Collins, Science Gossip, Jan. 1872, p. 9, with fig.
Floscularia trifolium . ; 2 Hudson, J. Roy. Micr. Soc. 2 Ser. vol. i. 1881, p. 4, pl. ii.

SP. CH. Lobes three, large, broadly curved, separated by very deep and similarly
curved depressions: dorsal lobe rather the largest; setee forming a continuous double
fringe round the entire circumference of the corona ; the outer row arranged like those of
F. campanulata ; the inner row short, slightly curved, aud arranged like cilia.

This large and elegant Floscule was discovered by Dr. F. Collins in 1865, in a small
pool near Sandhurst, Berks ; and he published a short account of it, with a figure (oc.
cit.) in 1872. It was afterwards found by Mr. J. Hood, in Loch Lundie, near Dundee,
in 1880; and I published a description of it (Joc. cit.) naming it I’. trifoliwm, as I had
considerable doubt of its really being Dr. Collins’ species. I have since seen the
description and figures which Dr. Collins sent, with some live specimens, to Mr. Gosse
in 1865; and I have now no doubt that F. trifoliwm and F’. trilobata are the same.

' Kindly identified by Dr. Cooke in a letter to Mr. Gosse.

FLOSCULARIAD A. 55

The peculiarity of a second fringe of sete lying within the principal fringe is shared
with it by F. Hoodii alone. Unlike the ordinary setiz, these smaller secondary sete
possess a kind of joint action; for when any captive creature tries to escape from the
coronal cup, and to pass the sete, those of the outer row either lash separately at it, or
are drawn together over it by the converging lobes; while a wave of motion, like a
ciliary wave, runs once or twice round the inner row. The true ciliary wreath can be
easily seen at the bottom of the coronal cup, owing to this Floscule’s great size and
transparency. I saw a small contractile vesicle, but I had no opportunity of tracing the
rest of the vascular system. ‘The two lateral antenne were also obvious.

The first thing that strikes the observer, on watching the protrusion of the furled
head, is the great size of the Floscule, and the curiously shrivelled appearance that the
lobes of the coronal cup present, as they emerge from the opening head. They look
exactly as if the animal were sickly or injured. In a few seconds, however, they gently
swell out, the many folds and creases disappear, till at last the eye is gratified with the
sight of a lovely transparent tulip, of three petals, their edges all fringed with delicate
and motionless hairs. It is a creature of exquisite beauty; from every point of view the
flowing curves of the cup are charming, and its great transparency permits the whole of
the outline of the rim to be seen at once. The dorsal lobe is rather larger than the other
two, and is curved forward over the cup. Across each lobe run delicate muscular
threads for furling it, which are specially visible on the back of the dorsal lobe
(Pl. II. fig. 6).

Dr. Collins saw eggs, laid by his specimens, remaining attached to them within the
tube; but Mr. Hood observed that some specimens, which he reared in a trough, hatched
the ova in the ovary, and then gave birth to the living young.

They are voracious feeders on Infusoria and small animalcules, and are fond of
stationing themselves in the axils of water plants.

Length, ,!, to ;; inch. Habitat. Lochs, marsh and boggy pools; Sandhurst (Dr.
Collins and P.H.G.); Woolston, Hants (P.H.G.); Fife, Forfar, Perth (J.H.): not
common in England, abundant in Perthshire.

F. Hoopi, Hudson.
(Pl. I. fig. 5.)
Floscularia Hoodii . F Hudson, J. Roy. Mier. Soc. 2 Ser. vol. iii. 1883, p. 161, pl. iii. figs. 1, 2.

SP. CH. Lobes three ; dorsal lobe much the largest, and carrying two, large, sleeve-
like, flexible processes ; sete, short, cilia-like, in two parallel rows, fringing the entire
circumference of the coronal cup.

This is one of the largest of all the Rotifera; adult specimens being quite 4‘ inch
from the top of the dorsal lobe to the extremity of the peduncle. Its great size, and its
curiously shaped three-lobed corona make it sufficiently remarkable; but, in addition to
these peculiarities, it has two extraordinary processes, perched one on each side of the
back of the dorsal lobe. They appear to be hollow, and to communicate with two
lenticular spaces lying between the two surfaces of the dorsal lobe. Fine muscular
threads pass along and across them (Pl. I. 5), and the animal can contract and
expand each independently of the other; and throw them into all kinds of positions.
The upper end of each seems to be separated from the lower portion by a constriction,
from which a muscular thread runs down to the base. Each of these processes slowly
and independently changes its shape and position, now sinking down on the dorsal lobe
so as to be invisible, or again bending its free end at right-angles to the lower portion.
I have never seen anything like them on any other Rotiferon: they may possibly be
organs of touch, but I could detect no trace of sete on them. Mr. Hood tells me that
both in young and adult specimens he has seen brown granular matter discharged from
their free ends. The thickened rim of the three lobes carries its double fringe of set

56 THE ROTIFERA.

set just as they are in F’. trilobata, the larger row stretching outwards, and the smaller
inwards ; and the same rapid flicker may be seen on occasions to run all round the edge
of the coronal cup. ‘The orifice of the coronal cup alters constantly, now opening in the
characteristic way shown in PI. II. fig. 5a, and now reduced to a slit; or even closed
in puckers. Two dorsal ridges, as in ’, ambigua, run like buttresses from the body to
the back of the dorsal lobe, and in the lowest portion of the deep hollow between these
lie the two pale pink eyes ; both in the neck, and one close to each buttress. The true
ciliary wreath is distinctly visible throughout its whole length. It is a long horse-
shoe-shaped and ciliated ridge, sloping sharply down from the bottom of the coronal
cup into the vestibule. The contractile vesicle is unusually large and distinct; close
to it, and apparently situated in it, is a cluster of yellow globules, which look black by
transmitted light.

This strange and beautiful Floscule was discovered by Mr. J. Hood in December
1882, in a ditch on Tent’s Muir, Fifeshire.

Length, ,‘; inch. Habitat. Marsh pools; Fife (J.H.): rare.

F. catva, Hudson.
(Pl. III. fig. 3.)

Floscularia calva . s . A Hudson, J. Roy. Micr. Soc. 2 Ser. vol. v. 1885, p. 610.

SP. CH. Lobes two, short ; dorsal lobe the larger; sete very short, radiating from
the thickened summits of the lobes, incapable of cilia-like action; body wruswally long
and narrow, its outline confluent with that of the coronal cup, so that there is no neck ;
eyes cervical.

Mr. J. Hood discovered this species in 1884 on a Sphagnwm leaf, in a mossy pool on
Tent’s Muir, only twelve inches deep, and on another occasion found it in Loch Lundie
at a depth of ten feet. I have seen only two specimens of it, and those under disadyan-
tageous circumstances ; as each had dropped from the plant on which it was found, and
was lying in the sediment at the bottom of the tube. The creature appears to attach
itself rather to its tube than to the stem of the plant which bears the tube, and so to
be easily detached. I am indebted to Mr. Hood for drawings of the young male and
female (Pl. IIL. figs. 8a, 8b), each of which he saw hatched from eggs laid in the tube.
The male is about +}, inch in length, and resembles that of /’. campanulata.

Length, ,j; to ,}; inch. Habitat. Lochs and marsh pools, on A/yriophyllum and
Sphagnum ; Forfar, Fife (J.H.): rare.

F. murapiuis, Bolton.
(Pl. III. fig. 2.)

Floscularia mutabilis . . Hudson, J. Roy. Micr. Soc. 2 Ser. vol. v. 1885, p. 609, pl. xi. figs. 1-3.

SP. CH. Lobes two, well developed ; dorsal lobe decidedly the larger ; sete rather
short, set round the whole circumference of the disk, and capable of cilia-like motion ;
eyes near the sumnut of the dorsal lobe.

F. mutabilis somewhat resembles F’. calva, but is at once distinguished by its
larger lobes, moveable setie, and by its unique habit of swimming. The animal has not
as yet been found attached to any water plant. It looks, when resting in its case at
the bottom of a live cell, just like an ordinary Floscule that had been knocked off its
perch, as the sete are straight and motionless. After a short rest it pulls down the two
lobes to a level with the bottom of the depressions between them, and so alters the corona

FLOSCULARIADAS. 57

that it looks like that of an G?cistes ; at the same instant the sets! set up a vigorous cilia-
like action ; and the animal, case and all, sails slowly, stern foremost, through the water.
Two red eyes are very conspicuous in a most unusual position ; namely, near the top
of the dorsal lobe. I have seen what I believe to to be the male (PI. III. fig. 2c), but I
failed to isolate it so as to make out its internal organs. Its length was about ,1, inch.
It appeared to have, in addition to the usual ciliary wreath, sete pointing backwards to
the foot.

Mr. T. Bolton discovered Ff’. mutabilis in a pond of Sutton Park, near Birmingham,
in May 1884. He described, named and figured it, soon afterwards, in one of the fly-
leaves sent out with his specimen tubes.

Length. About ,5 inch. Habitat. A pond in Sutton Park, Birmingham (T.B.) : rare.

FI. epentata, Collins.

(Pl. III. fig. 4.)

Floscularia edentata ; : . Collins, Science Gossip, Jan. 1872, p. 9, with fig.
” ” . . : Hudson, J. Roy. Micr. Soc. 2 Ser. vol. y. 1885, p. 611.

Corona loveless, transversely truncate ; sete very short, chiefly on the ventral and
dorsal portions of the rim; body large and stout in proportion to the animal’s total
length, and nearly as long as the foot.

Dr. Collins first discovered this ugly Floscule near Sandhurst in 1867. He says
(loc. cit.) that it has no masticating organs, and that the food passes directly into a
capacious stomach. As his specimen was a female (for it laid an egg while in captivity)
this is very unlikely. My specimens were so gorged with food that no internal organs
could be seen, except the stomach and a portion of the ovary. One of them was
literally crammed full of specimens of Cocconema, which not only distended the real
stomach and the erop, but even protruded above the rim of the coronal cup. How the
animal contrived, with its feeble cilia, so to pack itself with these unmanageable diatoms,
I cannot imagine.

Length. My specimens, ;!; inch; Dr. Collins’, ,4 inch. Habitat. Sandhurst,

55

Berks (Dr. Collins); Woolston, Hants (P.H.G.); Blair Athol (W. Dingwall): rare.

Genus ACYCLUS, Leidy.

GEN. CH. One dorsal, frontal lobe; sete absent, the coronal cup edged with a
delicate festooned menbrane ; termination of foot truncate.

* AcycLUS INquimtus, Leidy.?
(Pl. D. fig. 3.)
Acyclus inquietus ° . Leidy, Proc. Acad. Nat. Sci. Pa. 1882, p. 243, pl. ii. figs. 1-6.

The structure of this species has been only imperfectly made out ; but, so far as it has
been, the animal appears to be closely allied to the Floscularie@; and so also do the
next two species, Apsilus lentiformis, and Apsilus bipera. The characters of Acyclus
inquietus given by Prof. Leidy are as follows :—

“ Body fusiform, tapering behind into a long narrow tail-like appendage, by which
it is attached, not distinctly annulated, but becoming transversely wrinkled in con-

1 It is possible that there may be (as Mr. Bolton says) a row of short cilia round the coronal cup, as
well as the larger sete ; but my impression is that there is not: I altered my opinion more than once,
while watching the creature, but came at last to the conclusion that it swam by means of its sete, and
not by a subsidiary row of cilia.

* Throughout the work the species which are not known to be British will be marked with an
asterisk,

58 THE ROTIFERA.

traction. A non-ciliated cup-like head prolonged into an incurved digitiform appendage
(as a substitute for the usual trochal disc), contractile and retractile.”

The Professor found eight specimens of this strange creature, each surrounded by a
group of Megalotrocha alboflavicans, and all attached to the tubes of Plumatella diffusa,
in the Schuylkill river, U.S. It is considerably larger than M. alboflavicans, and can
be readily distinguished with the naked eye, towering above the surrounding cluster of
Megalotroche “like a giant in a crowd.”’ It is a very difficult animal to observe, as it
bends abruptly in different directions ; suddenly contracting and slowly elongating, and
scarcely ever for a moment remaining erect. It is translucent, whitish, with the thicker
portion of the body of a yellow or brown hue, due to the colour of the alimentary canal.
‘The corona is a cup prolonged on the dorsal side into an incurved lobe (PI. D, fig. 3).
It is capable of being expanded or contracted, protruded or retracted; and when ex-
panded, the dorsal lobe is also extended, but remains somewhat incurved. There are
no cilia or sete on the edge of the cup or lobe, but both of them are bordered by a
delicate festooned membrane. When contracted, the lobe is rolled up spirally (Pl. D,
fig. 8b). A narrow, transversely wrinkled neck lies between the cup and the body.
No ciliary wreath has been noticed within the cup. There is generally no tube
present; but in two instances the animal has been seen in a “ copious colourless
gelatinous sheath.” The cup converges into a pouch (the vestibule) occupying the
neck, which is seen to expand and contract from time to time. Longitudinal
muscles extend from the neck to the membrane surrounding the coronal cup, passing
along its walls. Retractor muscles stretch from the body down the length of the foot.
The secreting, vascular, and nervous systems have not been observed; neither have
any eyes or antenne in the adult female. The ovary is in the usual ventral position.
and the ova are large, and unsegmented when extruded.

Length, .}, to ;', inch. Habitat. Schuylkill river, U. 8. (Prof. Leidy): rare.

Genus APSILUS, Metschnikoff.
GEN. CH. Coronal cup wholly membranous ; setee and foot absent.
*ApsILUS LENTIFORMIS, Metschnikoff.
(Pl. D, fig. 4.)

Dictyophora vorax (2?) .« : 0 Leidy, Proc. Acad. Nat. Sci. Pa. 1857, p. 204, and
1882, p. 248, pl. ii. fig. 7.

Apsilus lentiformis . : : é Metschnikoff, Sieb. w. Kéll. Zeits. Bd. xvi. 1866, p.
346, with figs.

Cupelopagus bucinedax (2). : Forbes, Amer. Mon. Micr. J. 1882, pp. 102, 151, with fig.

Apsilus vorax . 6 ‘ : : Foulke, Proc. Acad. Nat. Sci. Pa. 1884, p. 37 pl. i. figs. 2, 5.

Apsilus lentiformis . 5 . : Leidy, Proc. Acad. Nat. Sci. Pa. 1884, p. 50.

Herr E. Metschnikoff found many specimens of this Rotiferon at Giessen in 1866, on
the under side of the leaves of the yellow water-lily, to which they were attached by a
chitinous ring on the ventral surface ; both in the young and adult female the foot was
absent. The coronal cup is wholly membranous, and destitute of either cilia or sete.
It is capable of having its edge all drawn close together into a point (Pl. D, fig. 4a), and
of being wholly withdrawn within the body, so that it acts as a net, closing over any
prey that voluntarily enters it, and foreing it down into the chamber below it, which in
the Floseules would be called the erop (fig. 4a, cp). At the bottom of the crop is a very
peculiar set of trophi (fig. 4c). A broad stomach has a cecal appendage on each side, and
a cloacal orifice on what appears to be the ventral side, but is really a portion of the
dorsal, having been drawn round by the animal’s curving its body when attached to the
leaf. There are two pear-shaped glands attached by their narrow ends to the crop.
There is a contractile vesicle opening into the cloaca, and from it, above, issues a

FLOSCULARIADA. 59

duet which divides into two lateral canals. Hach canal runs slantingly up to a coil at
the side of the body below the cup, and thence sends a branch into the dorsal surface of
the cup, anastomosing with its fellow above and below the neryous ganglion (Pl. D,
fig. 4b), and bearimg two vibratile tags on each side of it. The nervous ganglion is a
four-side organ in the dorsal wall of the cup; it sends out a nerve thread at each
corner, the lower pair passing to two lateral antenne. No eyes are visible in the adult.
The young embryo is developed in the egg in the body of the parent. When hatched,
it is a free-swimming Rotiferon (Pl. D, fig. 4d), with a truncate, ciliated, anterior ex-
tremity, and with the cloaca, at the ciliated posterior extremity, surrounded by a mem-
branous ring. There are two red eyes, but the characteristic coronal cup is as yet
undeveloped. The male, which has a ciliated foot, is so like those already described,
that Herr Metschnikoff’s drawings supersede description (Pl. D, fig. 4e).

Prof. Leidy described in 1857 (loc. cit.) a new Rotiferon, ‘ destitute of wheel-
organs,” which he named Dictyophora vorax. He obtained, however, some fresh
specimens in 1884, and is now of opinion (loc. cit.) that the animal is identical with
Apsilus lentiformis, and that the discrepancies between his account and Herr Metschni-
koff’s are due to the wrinkled condition of his first specimens, which had been forcibly
removed from the glass sides of an aquarium.

Mr. §. A. Forbes also described (loc. cit.) a Rotiferon found in a neglected aquarium,
and ‘wholly destitute of cilia or other vibratile structure.”” He called it Cupelopagus
buctinedax, and gave a very characteristic figure of its side view. I have little doubt
that this also is Apsilus lentiformis.

Length. Maximum about .}, inch. Habitat. On water plants, Giessen (Metschlmikoff) ;
Fairmount Park, and Schuylkill river, U. 8. (Leidy).

* ApSILUS BIPERA, Foulke.
(Pl. D, fig. 5.)

Apsilus bipera 0 0 0 3 Foulke, Proc. Acad. Nat. Sct. Pa. 1884, pp. 37, 50,
pl. i. figs. 4, 7.
Apsilus lentiforniis . é a Leidy, Proc. Acad. Nat. Sct. Pa. 1884, p. 50.

Miss 8. G. Foulke, who discovered this Rotiferon, is of opinion that it differs from
Apsilus lentiformis sufficiently to warrant its being regarded as a distinct species ; the
points of difference being the shape of the cup, the absence of ganglion, the presence of
a ‘second stomach,” and the ciliation of the cup.

If A. bipera really has two stomachs, one above the jaws and the other below them,
and each a closed sac with walls distinct from those of the body-cavity, then it would
not only be a new species, but also a perfectly unique one among the Rotifera. It is
evident that further investigation is wanted on this and other points; especially as
Prof. Leidy is of opinion that Apsilus bipera, Dictyophora voraz, and Apsilus lentiformis
are all the same animal.

But whether Miss Foulke’s species be a new one or not, to her is due the discovery
of a true ciliary wreath within the coronal cup. It consists of two gradually narrowing
ridges, fringed with long cilia, and rumiing up the inside of the dorsal surface of the cup
(fig. 5a). Short diagonal lines of finer cilia can be indistinetly seen between the larger set.
This ciliary apparatus is quite unique in position; and, if A. bipera and A. lenti-
formis are the same, it is curious that Miss Foulke should have missed the nervous
ganglion, and that Herr Metschnikoff should have missed the ciliary ridges.

Length. Up to ,) inch. Habitat. Water-plants in Fairmount Park, U.S. (Miss
Foulke). i

60 THE ROTIFERA.

Genus STEPHANOCEROS, Hhrenberg.

GEN. CH. Lobes long, slender, erect, convergent; sete set diagonally on the lobes
in parallel bands ; foot terminated by an adhesive cwp.

S. EICHHORNU, Hhrenberg.

(Pl. IV. fig. 1.)
Stephanoceros Hichhornii A 4 Ehrenberg, Die Infus. 1838, p. 400, Taf. xlv. fig. 2.

ss oH 5 : , Dujardin, Hist. Nat. Zooph. 1841, p. 612, pl. xix. fig. 8.
5 ap és 3 5 Gosse, Popular Sci. Rev. vol. i. 1862, p. 80, pl. ii. and iv.
Stephanoceros glacialis . . ‘ Perty, Zur Kenntniss kleinst. Lebensf. 1852, p. 47, Tab. i.
fig. 1.
Stephanoceros Eichhornit 0 R Leydig, Ueb. d. Bau d. Rdderth. 1854, p.5, Taf. i. figs. 1-4,
* 3 é 0 Pritchard, Infusoria, 1861, p. 668, pl. xxxii. fig. 383,
pl. xxxvil. figs. 1-4.
4 A "3 z : Cubitt, Mon. Micr. J. vol. iii. 1870, p. 240, pl. lii.
. a q 5 : Newlin Peirce, Proc. Acad. Nat. Sci. Pa. 1875, p. 121.
5 “3 , R : Rosseter, J. Roy. Micr. Soc. 2 Ser. vol. iy. 1884, p. 169,

pl. v. figs. 1-3.

Anyone who has seen Stephanoceros favourably placed, and properly lighted, can
well understand the enthusiasm with which Eichhorn relates its discovery '; for it isa
lovely creature, and as strange as it is beautiful. A small pear-shaped body, whose
rich green and brown hues glow beneath a glistening surface, is lightly perched on a
tapering stalk, and crowned with a diadem of the daintiest plumes: while the whole is
set in a clouded crystal vase of quaint shape and delicate texture. The tube is denser
than it is in the Floscules, is more symmetrical in shape, and is continuous in sub-
stance from its outer surface almost to the creature’s body. If an empty tube be
examined, it will be found that it has a central hollow, which the body and foot will
exactly fill.

Mr. Gosse and Dr. Mantell have each seen a young Stephanoceros bore its way
through its parent’s tube by means of its cilia ; just as I have several times seen young
Floscules do. The material, therefore, of which it is composed, must be of the flimsiest
kind. The commencement of the formation of the tube has been described by Mr. Gosse
(loc. cit.) as follows: ‘‘ A specimen, which was hatched under my eye, swam for ten
minutes, and then became permanently attached to the upper glass of the box, so that it
was vertical in its position, with the foot next to the eye; a favourable aspect for
observing the development of the case. It presently began to dilate its body ; and, in
about five minutes from its attachment, I perceived a distinct filmy ring around it, per-
fectly circular, whose diameter was about twice that of the body (Pl. IV. fig. 8). The
little animal now began to lean over to one side, and the ring soon had another segment
additional, leaning in the same direction (fig. 9). The case, for such it was, looked like
two broad hoops of glass, each swollen in the middle and set one on the other but not
quite concentrically, at least to the eye of the observer. It was manifest that it was
produced from an excretion from the body, owing its form and size to the animal’s moy-
ing round on the foot as on a pivot.”

Ehrenberg’s drawing of Stephanoceros has certainly been taken from a crushed or
sickly specimen, and, indeed, in the majority of cases its portrait has been drawn too
long after the creature had left its native haunts; for when freshly caught and in
vigorous health it arches its five plumes so that its crown almost forms a sphere.2 The

1 P. 18, supra.

2 Mr. Gosse has found that healthy specimens, removed from an aquarium and inspected at once,
have their five arms more frequently produced into a cylindrical form, with their extremities incurved,
than arched into a sphere.

FLOSCULARIADAS, 61

sete are far longer than they appear at first sight, and are not stiff bristles as Ehrenberg
has drawn them, but are gracefully curved, and taper off into lines of exquisite fineness.
Those of one arm interlace with those of the arms on either side of it, so as to form a
living cage of the finest network, through which it is hardly possible for anything to
pass without striking some part of the sensitive meshes. The instant this happens band
after band of the sete lashes at the runaway, a swift wave of motion runs along each
band, and the captive is thrown back into the vortex produced by the wreath at the
bottom of the coronal cup, the ciliary armature of which is precisely like that already
described in Floscularia. I have also on more than one occasion detected a fitful ciliary
wave running round the top of the coronal cup, just under the level of the lowest points
of the depressions between its lobes. This has not hitherto been noticed, but I am
certain of the fact : the motion was of the briefest duration.

There are considerable differences of opinion about the muscular system. Dr. Leydig
(loc. cit.) says that there are four muscles which rise in the foot, and each of which divides
into a pair, as it crosses the trunk, and then subdivides into smaller branches, as it passes
over the coronal cup to the base of the lobes. Mr. Gosse makes them to be five pairs,
and says that usually each pair runs up the trunk from the foot in a line with one of the
arms; and then, before reaching it, divides into diverging branches which, at remote
points, are united to a muscular collar close to the base of the arms. He notices, how-
ever, that he has seen cases where the muscles run down direct from the depressions
between the lobes without uniting to form pairs.

My own opinion, after prolonged observation of many specimens, is that there are
really six pairs of muscles, and that they are arranged in the following fashion. Tach
pair runs up the foot looking like a single muscle ; and the reason why never more than four
(pairs) are visible in the foot from any point of view, is that there is always a pair on
each side of the animal (however viewed) which is there lost to sight. At the junction
of the foot and trunk each pair begins to open a little ; and by the time they have reached
the bottom of the coronal cup the constituents of each pair diverge obviously from each
other, and terminate usually at the base of some one of the depressions between the
lobes: but in such a fashion that the constituents of the same pair never end in the
same depression (Pl. IV. figs. 2, 3, 4, /m). There is, however, an exception to this in
the case of the two pairs of dorsal muscles (PI. IV. fig. 2, lm). Here it will be seen
that while the outer muscles in each pair end in a depression between the lobes, the
inner muscles curve over towards each other and meet so as to form a fine arch, some
distance below the base of the dorsal lobe. There are, too, fine hexagonal markings
visible on this side of the coronal cup, which are probably the boundaries of large cells :
oval nucleated cells are also easily seen in the wall of the coronal cup, when the animal
is viewed from either side (fig. 4).

The nutritive and reproductive systems are so similar to those of Floscularia, that
they require no separate description. It is enough to call attention to Dr. Leydig’s
figure of the ovary treated with acetic acid (reproduced in fig. 7), and exhibiting the ova
in various stages of growth, as well as its own delicate walls, and the oviduct (ot), which
leads into the cloaca (cl).

The Secreting System.—Neither salivary, gastric, nor foot glands have been observed
in Stephanoceros, but as the animal secretes a large and comparatively solid tube, it is
clear that it must either have some organ for this purpose, or that the substance of
which the tube is constructed oozes from the surface of the body.

The vascular system is much better seen in this genus than it is in the preceding.
Fig. 4 shows Stephanoceros viewed a little obliquely from the side on the left of the
dorsal surface. The left lateral canal (fig. 4, Jc) can be seen winding to the left of the
nervous ganglion (gi) and having two vibratile tags (vé,, vt.) attached to it close to where
the left eye (e) is. The lateral canal then divides into two branches ; the right branch
curving upwards towards the dorsal surface to meet its fellow on the median dorsal line
(see fig. 2), while the left branch passes along the side of the vestibule till it nearly

62 THE ROTIFERA.

reaches the level of the knobbed ends of the ciliary wreath (ew). Here this left branch
joins an offshoot of the right branch; the point of junction being marked by a third
vibratile tag (vt;). A fourth vibratile tag (vt,) is attached to the right branch just where
it gives off the connecting offshoot, and a fifth (vé,) can be seen on the highest dorsal
portion of the lateral canal. Fig. 2 shows the same right and left canals, as seen from
the dorsal surface, with the same vibratile tags on either side. Each lateral canal winds
down the side of the trunk and ends at last on the surface of the contractile vesicle.
Leydig (loc. cit.) records his having distinctly seen this junction in young specimens, as
well as a duct leading from the contractile vesicle into the cloaca (cl).

The Nervous System. What is probably the nervous ganglion is a peculiar organ
(figs. 2, 4, 5, gn) consisting of large clear cells, lymg at the back of the vestibule
near the dorsal surface. Above it, and well under the dorsal surface, is a three-lobed,
granular, semiopaque body (figs. 2, 5, v) with which the nervous ganglion is possibly
connected. The nervous ganglion in many of the Rotifera, especially among the
Notommatade, shows a marked cellular structure at the lower end which loses itself
in a granular, semiopaque upper portion; but it must be admitted that if these peculiar
bodies (gn, x) constitute the nervous ganglion of Stephanoceros, it is rather their posi-
tion than their shape and structure that would lead us thus to interpret them. From
the spot where it adheres to the wall of the vestibule, a sort of protrusile tongue or
taster (fig. 4, tv) rises which can be pushed forward so as nearly to fill up the interval
between the knobbed ciliated ends of the ciliary wreath. This tongue may be seen
incessantly pressing backwards and forwards as the food passes into the vestibule, as
if discriminating between the passing atoms, just as the two tasters do in MW. ringens.'
The eyes (fig. 2 e) lie on either side of the nervous ganglion ; they may be seen by dark-
field illumination, but as they are small, rather deep down under the surface, and often
obscured by other parts, it is not easy to get both into view at once. Mr. Cubitt
(loc. cit.) describes and figures them as clear globes resting on pigment spots, and
with nerve threads attaching them to the nervous ganglion: this is a very probable
structure, but I have failed to make it out. Two very short lateral antenne (Figs. 2,
5, a) can be seen when Stephanoceros is viewed dorsally: they are mere setigerous
pimples.

The development of the young is shown in Mr. Gosse’s figures (Pl. IV. figs. 8 to 15),
in which fig. 8 represents young Stephanoceros a few minutes after birth ; figs. 9 and 10,
a little later ; and figs. 11 to 14 represent successive stages of growth of a specimen
from three to eighteen hours old. Fig. 15 shows the perfectly developed young Stepha-
noceros, thirty-six hours old; it exhibits the bands of sete, the principal viscera, the
muscular collars, vestibule, crop, and jaws. Mr. Rosseter (loc. cit.) says that on one
occasion he watched the development of a young Stephanoceros and noticed that the
lobes of the corona “ originate as buds and unroll like the fronds of ferns ”’ (figs. 16, 17).
These buds began to appear about eleven hours after the animal was hatched, and when
they had risen to a small height gradually unfolded; they remained in a drooping state
for two days, but on the third day took the arched form usual in the adult. Dr.
Mantell observed a young specimen in which the lobes even after eighty hours from
birth were mere rudimentary buds. Such discrepancies in the rate of development
noticed by these three observers are common in all the Rotifera, and are doubtless
partly due to the various degrees of development that the embryo attains in the ovum
before its extrusion. In Stephanoceros (as in a few other Rotifera) the young (as
Ehrenberg conjectured) is occasionally born alive. This has been seen by Mr. Rosseter
and Dr. English,? and indeed is almost shown in Dr. Leydig’s figure (Pl. IV. fig. 1s
where the much advanced embryo (y) lying close to the oviduct (ot) already exhibits the
eyes and frontal cilia.

1 (PI. V. fig. 2 ¢, t). 2 See Mr. Rosseter’s paper (Joc. cit. p. 171).

FLOSCULARIADAL. 63

No male has as yet been recorded, but Leydig’s fig. 8. Taf. i. (doc. cit.), of a young
Stephanoceros forced out of the ege by pressure, has a very masculine look about it.

Disease.—Mr. Gosse (‘‘ Popular Sci. Rey.” loc. cit.) has noticed that Stephanoceros
will occasionally throw off portions of one or more of its lobes, which slough away so as
to be reduced to mere stumps. As Mr. Gosse remarks, there is little doubt that Perty’s
S. glacialis (loc. cit.) is only such an unhealthy specimen of S. Hichhornii. I have
seen the same thing ; and I have noticed that, when a portion of the lobe sloughed off,
the discarded piece would round itself into a globe, and float away urged by the fitful
lashing of the sete on it.!

Length, = to ; inch. Habitat. On weeds in clear ponds in the neighbour-
hood of London (P.H.G.); of Birmingham (T.B.); in marsh pools on Sphagnum,
Perthshire (J.H.). Very partially distributed; not uncommon about London and
Birmingham, but rare in Scotland, and very rare apparently in America. Widely
spread on the Continent.

' Mr. Newlin Peirce (loc. cit.) has written a strange account of a Stephanoceros that accumulated a
mass of débris in the upper portion of its tube; and then, dividing itself transversely at the level of
the débris, deserted its tube, carrying the accumulation with it, and attached itself to another stem of
the plant to which it was originally fastened. Here it gradually became a perfect animal in a new
tube ; and it then repeated the process. The whole account is incomprehensible.

CEA THR Vi.

PRRRDRR rn

MELICERTADA:.

Chaque genre de Vers, et j’ose presque dire chaque espéce, offre un objet tout 4
fait neuf, qui demande a lui seul presqu’autant de travail que les classes entiéres
des grands animaux.—Gerorrroy Sr. Hmarre,

What, dull! when you do not know what gives its loveliness of form to the lily,
its depth of colour to the violet, its fragrance to the rose! when you do not know
in what consists the venom of the adder, any more than you can imitate the glad
movements of the dove! when, unlike the wisest of monarchs and of men, far
from knowing the trees as he did, “from the cedar tree that is in Lebanon even
unto the hyssop that springeth out of the wall,” you do not know anything even
of the two extremes of Solomon’s great knowledge! What, dull! when earth, air,
and water are all alike mysteries to you! and when, as you stretch out your hand,
you do not touch anything the properties of which you have mastered! while, all
the time, Nature is inviting you to talk earnestly with her, to understand her, to
subdue her, and to be blessed by her! Go away, man; learn something, do some-
thing, understand something, and let me hear no more of your dulness.— SIR
ArtHuR HELps,

CHAPTER VI.

Family Il. MELICERTADA.

Corona not produced into setigerous lobes ; buccal orifice lateral ; ciliary wreath a
marginal continuous curve, bent on itself at the dorsal! surface, so as to encircle the
corona twice, with the buccal orifice between its upper and lower curves, and having also
a dorsal gap between its points of flexure ; trophi malleo-ramate.

The Melicertade@ are at once distinguished from the Flosculariad@ by the difference
of the corona, and the unsymmetrical position of the buccal orifice. In all the genera
the corona bears two parallel wreaths of cilia, the upper of which frequently presents the
appearance of a revolving wheel. The family contains seven genera, which differ from each
other mainly in their coronx, tubes, and habits ; their internal structure being so much
alike, that it has been proposed, more than once to reduce the seven genera to two.

There is no more interesting family. It contains animals that build their own tubes,
pellet by pellet; and that themselves form these pellets, either out of external materials,
moulded in hollows of their own bodies, or out of their own fieces. All have social
instincts: some rearing their tubes, to the fourth and fifth generation, on those of their
ancestors, or forming dense clusters on the stems of water-plants; and others (fixed
forms only in a sort of Parliamentary sense) adhering to each other by their posterior
extremities, and forming spherical clusters that roll unceasingly through the waters of
still lakes and ponds. Most of them are hardy, and luckily all are prolific ; sometimes
so amazingly that the water-weeds are literally covered with their tubes, and the
fortunate finder can thus have in the small compass of a live box scores of animals of all
ages, and in every stage of growth.

Genus MELICERTA.

GEN. CH. Corona of four lobes ; dorsal gap wide ; dorsal antenna minute ; ventral
antenne obvious.

The tube varies in all the four species, and its structure and formation will be
described under each. In all there is an inner gelatinous tube,” and in M. ringens and
M. conifera there is also an outer tube, consisting of pellets of extraneous matter ;
while in MZ. Janus the pellets are fecal. In M. tubicolaria the outer tube is entirely
absent.

The corona seen dorsally looks somewhat lke a heart’s-ease, with its four petals
lyimg in a plane; but a side view shows that the two lower lobes are bent upwards,
so as to form an oblique angle with the upper lobes. A groove runs round the
corona, on both sides, just under its edge; and on the ventral surface it is confluent
with the buccal funnel. There is a gap in the groove on the dorsal surface, so that
it does not entirely surround the corona. The edge of the corona is fringed with large
cilia, and the edges of the groove and buccal funnel with much smaller ones ; and they

' In one instance (that of Conochilus volvor) read ventral for dorsal.
* This inner tube can be seen in the young animal (PI. V. fig. 1d and Pl. VI. fig. 1g) before the
outer tube has been completed.

68 THE ROTIFERA,

are all in constant motion. The action of the former, or principal, wreath (Pl. V. figs. 2c,
4, pw) draws the particles floating in the water into two spiral currents, which are tangen-
tial to the groove on either side of the disk. The action of the latter, or secondary wreath
(Pl. V. figs. 2c, 4, sw) drags the particles, as in their spiral path they strike the groove, out
of that path into the groove itself, and hurries them along its windings towards the buecal
funnel. At the two points where the groove on each side joins the buecal funnel are two
fleshy knobs (Pl. V. fig. 2c, tr), which can be seen in constant motion ; either regulating
the force of the current, examining the moving atoms, or possibly performing both offices
at the same time. ‘The ciliated edges and sides of the buccal funnel conduct a portion of
the stream down to the mastax ; while another, and apparently the larger portion, rushes
oyer the ciliated chin.' Ifa little carmine be added to the water, it is a pretty sight to
see the coloured spirals form on both sides of the corona, while two processions of
crimson atoms wind in and out under the margin of the petals, one on the left hand, and
one on the right; each starting from the dorsal gap, and dashing at last down the
buccal funnel, or over the chin. (PI. V. figs. 2c, 4, ch.) But the whole of the ciliary
apparatus has not yet been noticed. Beneath the chin there is a hemispherical hollow
(Pl. V. figs. 2c, 4,cc) which is furred with minute cilia. It is in this cup that M. ringens
and M. conifera mould their pellets, as will be described further on? ; it is present also
in M. twhicolaria and M. Janus, but its function in these species is unknown.

The Nutritive System.— The buccal funnel (PI. V. figs. 2c, 2d, 4, bf) slopes downwards,
and somewhat dorsally, towards the mastax. Itis ciliated throughout, and has a pair of
chitinous lips (fig. 2d, lp) similar to those described at p. 6. These lips are in frequent
motion, now opening and shutting, now moving up and down the funnel, evidently
selecting and rejecting the food: if an objectionable morsel attempts to pass, ‘‘ it is
astonishing to see how the little quick jerk, which the lips give, tosses it up into the
central stream of waste and drives it away.”’* Should this morsel be unusually large,
the mastax itself aids the lips in their upward jerk. On each side of the buccal funnel
and above the mastax is a clear organ (PI. V. fig. 2d, sy) whose surface is spheroidal.
The two have been described as salivary glands by some observers, and as mere stays
to the mastax by others. They are obviously elastic, and move up and down with its
every motion. The mastax (fig. 2d, ma) consists of three confluent lobes, presenting a
trefoil outlne in vertical section; each side-lobe contains a malleus, and the bottom-
lobe grasps the incus. The malleo-ramate trophi (Pl. V. fig. 1f) are almost precisely
similar to those already described.

The food flows between the lips, and after having been torn by the sharp teeth of the
mallei, and crushed by the ridged inner surfaces of the rami, passes through a short
ciliated cesophagus (fig. 4, @), and so enters the stomach (fig. 4,s). This is a long
cylindrical sac, with very thick walls of large cells, lined with cilia. A partial con-
striction usually separates it from the intestine (7). The walls of this latter are thinner
and more transparent, and their cilia longer. The distinction between the stomach and
intestine is obliterated when the stomach is much distended with food, but is usually
present, and is often rendered obvious by the difference of colour in the contents of the
two. Those of the intestine revolve under the action of its cilia; and when the pellet
thus formed is ready for extrusion, the animal lifts its cloaca above the rim of its cup
pushes up the pellet, bends downwards over it, and then dexterously shoots it across
its shoulder into the current flowing from the chin, By this means the feces are
carried away out of the currents of the trochal disc.

The Seereting System.—The so-called salivary glands I have already noticed. There

' Judge Bedwell (Mon. Micr. J. vol. xviii. 1877, p. 216) describes in M. ringens a hemispherical
cushion, placed at an angle on that side of the buceal funnel which is opposite to the chin. He thinks
that it is a highly sensitive organ, which, by altering its facial configuration, directs the streams that
go down the bueeal funnel and over the chin, and drives suitable particles in appropriate directions.
I have not, however, been able to confirm those observations.

AP p Oils + Judge Bedwell (loc. cit.).

MELICERTAD AS. 69

are two moderate-sized gastric glands (PI. V. fig. 2d, gg) in the usual position at the top
of the stomach; and Mr. Gosse describes in M. ringens ‘near the tip of the foot on its
ventral side, a little granular body connected with the tip by a point, and enlarging at
the upper end where it is connected with a small globular vesicle.’’! He suggests that
this is a foot-gland similar to that in so many other Rotifera.

The Vascular System.—The contractile vesicle is very small, and is generally hidden
by the viscera; it les close to the rectum. When the animal is viewed sidewise, the
lateral canals can be traced from a knot of twisted tubes in the shoulder to a similar knot
in the corona. Two vibratile tags can be seen at each knot. The lateral canals he close
to the surface, and can be best found by slowly focussing upwards from any point near
the shoulder, and just under the cuticle. It is possible to trace them down from the
shoulder to the contractile vesicle ; but it is not often that the viscera lying beneath
permit this to be done.

The Reproductive System.—The ovary is similar in structure to those already
described ; it is somewhat oblong in shape, and extends between the stomach and ventral
surface, over nearly the whole of the latter. The oviduct passes beneath the intestine,
andin M. ringens ‘‘ enters the cloaca near the point where the lower stomach [intestine]
opens into the excretory canal.” ?

The Nervous System and Organs of Sense.—The nervous ganglion has as yet only been
made out in M. ringens. M. Joliet (loc. cit. M. ringens) describes it as a group of big
cells of a very characteristic form, and provided with a large nucleus. Many similar
cells are placed beside the first, and stretch in different directions. It is not large, and
is situated on the dorsal face of the pharynx. The two ventral antenne (figs. 2c and 4, a)
are very obvious. Between them lies the buccal funnel, as well as the tract which, in
M. ringens and M. conifera, is engaged in forming and depositing the pellets ; and which
contains the chin (ch), the ciliated cup (cc), and a prominent knob lying just under it.
The antenne are tubes, with a short transverse plug in them, carrying a pencil of delicate
sete. This plug can be withdrawn into the tube at will, by a muscular thread; the top
of the tube itself following the plug, just as ina snail’s horn. They are so situated that,
when Melicerta furls its corona, they stand on the top of the round closed head (fig.
Ic, a). Immediately opposite to them, in M. ringens and M. conifera, there are two
curved sharp hooks (i), which look like weapons of defence; and between them hes the
third antenna, the dorsal one, which igs nothing but a setigerous pimple. Two red
eyes are visible in the young, but none as yet have been seen in the adult.

The Muscular System.—The longitudinal muscles, as in the Floscwlariade, run up the
foot to its junction with the trunk, where they are fastened. They then cross the trunk
till they reach the neck, where they are again fastened ; and as they reach the head they
divide into branches, which cross the lobes of the corona, and, by their contraction, furl
it. Transverse muscles, imbedded in the integuments, encircle the trunk; and, by the
compression of the body-fluids, drive out and unfurl the corona, just as in Floscularia.
In M. conifera I have observed a set of longitudinal branching muscles, which are
inserted in the neck, just under the ciliated cup, and the prominent knob beneath it
(Pl. V. fig. 2e, lm). Itis by their varied action that Melicerta is able to curve and
twist its neck, and clinch its pellet on to the top of the tube, by the opposing pressures of
the knob and chin.

The male has not yet been certainly recognised. I have seen what is probably the
male of M. tubicolaria,? and Judge Bedwell gives a graphic description of the probable
male of M. ringens,* and of its coquetting with the female; Mr. Gosse has also seen what
there is little doubt was the male of M. conifera.?

' Quart. J. Mier. Sci. vol. i. 1853, p. 71, pl. ii. fig. 22.

? Professor Williamson, Quart. J. Micr. Sci. vol. i. 1853, p. 1.

* See p. 73 and Pl. V. fig. 3c. § Midland Naturalist, vol. i. 1878, p. 245; see also p. 71.
* See p. 72.

70 THE ROTIFERA.

M. rincens, Schrank.
(BIE Vacs 12)

Melicerta ringens . 5 c : Ehrenberg, Die Infus. 1838, p. 405, Taf. xlvi. fig. 3.

os : r 6 0 6 Gosse, Trans. Micr. Soc. vol. iii. 1852, p. 58, pl. xii. figs. 1-4.

Fog Py 0 5 . ; » Quart. J. Micr. Sci. vol.i. 1853, p. 71, pl. ii. figs. 12-27.

ms a 0 ‘ ; é » Popular Sct. Rev. vol. i. 1862, p. 474, pl. xxvi. figs. a, b.

7 Ps ; . 4 F Pritchard, Infusoria, 1861, p. 672, pls. xxxii., xxxvi., xxxvii.

a * ; a 5 5 Williamson, Quart. J. Micr. Sci. vol. i. 1853, p. 1, pl. i.
figs. 14-34.

4) % : 5 5 . Leydig, Ueb. d. Bau. d. Réderth. 1854, p. 17.

eA " 5 6 : 5 Claparede, Ann. Sci. Nat. Zool. 5 Sév. t. viii. 1867, pl. iii.
figs. 1, 2.

A vy 3 6 fs A Cubitt, Mon. Mier. J. vol. v. 1871, p. 205, pls. Ixxxiil., Ixxxiv.

= Js : ' 5 P », Mon. Mier. J. vol. viii. 1872, p. 8, pl. xxiii. fig. 2.

a un . A : A Bedwell, Mon. Micr. J. vol. xviii. 1877, p. 214, pls. exevii.
and exeviii.

ss 7 : A A A J. Roy. Micr. Soc. vol. i. 1878, p. 176, pl. x.

9 on 4 C 6 4 Mid. Nat. vol. i. 1878, p. 245.

” ” . ° . é Hudson, J. Roy. Micr. Soc. vol. ii. 1879, p. 6.

A A 5 - é Joliet, Comptes Rendus, t. 93, 1881, pp. 748, 856.

SP. CH. Lobes when expanded, wider than the tube; chin short, extremity blunt ;
pellet nearly spherical.

During the hundred and eighty years which have elapsed since Leuwenhoek dis-
covered M. ringens, it has been a source of delight to a long succession of observers. It
has had more than a dozen names given to it, and has been the subject of upwards of
three times as many treatises ; and no wonder, for the surprising spectacle of its whirling
disk captivates even those who have seen it scores of times before.

Then the building of its tube appeals powerfully to the imagination. Here is a tiny
creature which, when barely an hour old, and not +3, of an inch in length, sweeps from
the water its food and the materials for its dwelling; and which, at the same moment,
and with faultless accuracy, sorts the one from the other, and both from the mere
rubbish, drives away the waste, sends a stream of food down its throat, supplies
selected atoms to a brick-making machine in its own body, mixes them with cement,
moulds them into bricks, and finally (to crown the marvel) lays the bricks one by one
around its body in regular order, so as to form a compact and effective dwelling.

Leuwenhoek saw, and clearly described, the laying of the pellets and the raising of
the tube ; but failed to see how the former were produced. Indeed, even what he did
discover was forgotten, so that Mr. Gosse’s paper ‘‘ On the Architectural Instincts of
Melicerta ringens ” (in which the process of forming the pellets and tube was completely
described) roused the greatest desire in all microscopists to see this marvel for themselves.

It is unnecessary for me to quote once more passages that are to be found in every
text book, but I will continue the description (interrupted at p. 68) of the various streams
that are set in motion by the ciliated borders of the corona, buecal funnel, and chin,
and briefly tell how the pellets and tube are formed.

The main stream of waste, that rushes over the chin, has two feeble currents running
under the somewhat incurved edges of the buccal funnel: at the side of its banks, if I
may sosay. Along these two currents float very minute atoms, at a comparatively
gentle rate, while the larger particles dash along in the main stream. As the former
glide along the banks of the buccal funnel they come to a notch on either side of the
chin, over which they slip and are then drawn by the action of connecting lines of fine
cilia into the ciliated cup, that lies close beneath the chin. ‘This cup is nearly hemi-
spherical in shape, and is furred with fine cilia. Soon after it has been emptied of one
pellet, another begins to form in it, and a minute sphere of particles, generally of a
yellowish-brown colour, is seen whirling in the centre of the cup. As this rapidly

MELICERTADA. 71

grows in size from the addition of fresh matter, it is easy to see in what direction it
rotates, by means of the darker specks on its surface. If these are watched, it will be
found that every now and then the rotation is reversed, and that this happens many
times before the pellet is completed. It is needless to credit Melicerta with the volun-
tary alteration of the motion, for it is obvious that a pellet, kept in the centre of a ciliated
cup by the action of its cilia lashing up and down, must be in an unstable position; a
very little alteration of its own figure, or of its centre of gravity, or of the relative power of
the cilia in different parts of the cup, would be sure to drive it out of its central position
to one side or the other. This done, the cilia on that side (say the lower one) would
be checked, and those on the upper would have the predominance, and so force the
pellet to rotate towards the upper side; which when it had slowly reached, the upper
cilia would in their turn be checked, and the lower cilia would now have the pre-
dominance, and would again draw the pellet towards themselves, reversing the rotation
—and soon. The particles in the cup are made to adhere by being mixed with the same
glutinous secretion as that which forms the inner tube. This exudes either from the cup
itself or (as I believe) from the surface of the large knob just beneath it (PI. V. fig. 2c).
In a minute or two, from the commencement of the process, the pellet is completed, and
then the animal bends its neck swiftly over the edge of the cup, and clinches the pellet
on to the top of the inner tube, by the opposing action of the chin and the knob beneath.
It is obvious that it selects the place in which to deposit the pellet, and it is probably
guided to the exact spot by its dorsal antenna, which is generally close to the spot the
instant before the pellet is laid.! It is curious that Ehrenberg should have completely
missed the way in which the pellets and tube are formed. He says that the former ‘‘ are
not foreign bodies (as in the tube of Phryganea) nor excrement; but a peculiar substance
mixed with the latter, gummy, and hardening in water”: and he further says that he
distinctly saw the pellet discarded from the posterior intestinal opening, and fastened by
it to the tube. Mr. Gosse, who calls attention to this discrepancy, suggests that there
may possibly be ‘‘ two species closely allied but differing in this part of their organisation
and economy ”’; and the discovery of M. Janus, which has precisely the habit wrongly
ascribed to I. ringens, shows how shrewd was Mr. Gosse’s suggestion. The only difficulty
about the matter is that Ehrenberg’s drawings are certainly taken from M. ringens ;
while his description of the formation of the pellets and tube seems to be taken from
M. Janus. Possibly he may have found first the one, and then the other, and not dis-
tinguished between them; though that seems hardly likely.

Melicerta ringens in England does not usually occur in clusters of adhering indi-
viduals, though occasionally one is seen with a young one or two attached to its tube.
But in the United States (as I have already noticed) it frequently occurs in large clusters,
and some of the tubes of these clusters greatly exceed in size the largest known English
specimen. For instance, I possess a cluster in which the central tube is } of an inch
long, and of which therefore the tenant must have been upwards of } of an inch in
length, thus exceeding even the great length of Floscularia Hoodu. I found that this
great tube contained upwards of six thousand pellets arranged in about two hundred
and forty rows, one above another.

The Male.—Judge Bedwell in the ‘‘ Midland Naturalist ”’ (loc. cit.) describes a small
free-swimming Rotiferon which he saw emerge from a tube of Melicerta ringens. It
was not more than } of the length of the tube, had a forked foot, and trophi somewhat
like an inverted W, which were capable of protusion through the corona. Like the prob-
able male of M. conifera,? it began to woo and caress the lobes of the female in the
most active and elegant manner, almost as if it were nibbling the main wreath of cilia.
Now to anyone accustomed to watch Melicerta, it must always be a matter of astonish-
ment to see such a timid, nervous rotifer allow another to touch the cilia with impunity ;
but in this instance the female never flinched in any way, but accepted the attentions of

' Judge Bedwell, Mon. Mier. J. (loc. cit.). The whole paper is most suggestive.
2 See Mr. Gosse’s description, p. 72.

72 THE ROTIFERA.

the little visitor with perfect composure, and continued to feed as if quite undisturbed
by its presence.” The same observer broke up about fifty tubes of I. ringens in
December, and procured ten specimens of the same small Rotiferon from them: in one
case there were four males in a single tube.

In the above account, the presence of a forked foot, and of a mastax and trophi, and
the fact that the latter were seen to be protruded from the corona, would naturally lead
one to say that the Rotiferon recorded was rather some one of the Notommatade than a
male Melicerta. On the other hand, its unresented action towards the female was pre-
cisely that noticed by Mr. Gosse in the case of M. conifera; and the latter observer has
also seen trophi in a very similar creature with similar habits, which he believes to be
the male of Limnias ceratophylli.}

Length. Varies greatly. Average length of an adult tube about ,), inch. Specimens
twice the size are common in Scotch lakes. Those in clusters, in Philadelphia, U.S.,
extend even to } inch. Habitat. Very common on water plants, in standing or slowly
running water.

M. conirera, Hudson, sp. nov.
(Pl. V. fig. 2.)

SP. CH. Lobes, when expanded, of the same width as the tube; chin long and
pointed ; pellet a pointed cylinder.

This Melicerta is somewhat larger, and very much rarer, than M. ringens. It was
discovered by Mr. J. Hood in 1876 in a pool on Tent’s Muir. He found it again in pro-
fusion in the summer, autumn, and even in some of the winter months of 1879, the
weed being quite matted with it. The points of difference between it and I. ringens
are persistent, though slight ; but the difference in their tubes is striking. This is due
to the shape and quality of the pellets. They are much longer in proportion to their
diameter than those of M. ringens, so as to resemble a conical rifle bullet ; and they
are more transparent, and of a clear golden yellow. In consequence of their length the
tube is a stout one, and its thickness is shown by a stripe on each side of a different colour
from the centre of the tube, and darker or lighter according to the illumination used.

The fully expanded lobes are almost exactly as wide as the top of the tube, but in
M. ringens they exceed it in the proportion of ten to nine. The chin, too, differs from
that of the common species; it is longer and more pointed.

The Male.—[In water from Epping Forest sent to me by Mr. Henry Davis, I found
Melicerta conifera, projected and rotating. Emerging from the mouth of the tube, about
three-fourths extruded, was a male (PI. D. fig. 6) about as long as the diameter of the
tube, playing, as it were, with the disk of the female. Two irregular shaped opaque
masses were seen in it far apart from each other. [looked away for a minute to delineate
what I had seen, and he was gone: but I presently found him slowly swimming around,
which he continued to do, turning on his long axis as he went. There was now only one
opaque mass, the hinder ; and this was in contact (whether in connection I do not know)
with a large ovate clear bladder, perhaps an air vesicle. The head is oblique, the face
ciliated, the occiput, angled and projecting. The foot is a little knob of flesh. I could
see no internal organs, nothing but the clear, colourless tissue, full of corrugations
throughout. P.H.G.]

Length. About ,; inch; tube, }; inch. Habitat. Marsh pools, Fife and Perth
(J.H.) ; abundant in a pool at Snaresbrook (P.H.G.): rare.

M. tuprconaria, Ehrenberg.

(Pl. V. fig. 8.)
Tubicolaria Naias . a : Ehrenberg, Die Infus. 1838, p. 399, Taf. xlv. fig. 1.
” ” . Leydig, Ueb. d. Bau. d. Rdderth. 1854, p. 14, Taf. i. fig. 7.

) See p. 76.

MELICERTAD AS. 73

Tubicolaria Naias . e : : Pritchard, Infusoria, 1861, p. 668, pl. xxxii. figs. 379-382.
Melicerta tyro . 5 c z 2 Hudson, Mon. Mier. J. vol. xiv. 1875, p. 225, pl. exix.
Tubicolaria Naias . = 7 . Fullagar, J. Quekett Micr. Club, vol. iv. pp. 182, 202,

pls. xvi.—xviii.

Lobes, when expanded, more than three times the width of the body ; antenne very
long ; tube a gelatinous sheath without pellets.

Three striking peculiarities at once catch the eye in this beautiful Melicerta, viz.
(1) the great size of the trochal disk; (2) the wonderful length, backward setting,
swollen bases, and great flexibility of the ventral antenne; and (3) its semi-trans-
parent tube, which, though resembling that of the Floscules, has yet a character of its
own.

The tube, unlike those of all the other species, bears no pellets at any time. It is
of a loose fluffy texture, and extends from the surface almost up to the Rotiferon itself.
There is a central hollow, little wider than the creature’s body, up and down which the
animal moves. Horizontal layers of diatoms, and other foreign bodies, cross the tube at
irregular intervals, and mark the height at which the tube then was, when they were
entangled.

The corona is very large. It is more than three times the width of the body; thus
considerably exceeding the proportions of MZ. ringens and I. conifera. Its four lobes
are really all curved, just like those of JZ. ringens, and are often seen fully expanded
and round; but the animal has a habit of bending the corners of the two upper lobes,
so as to give the whole disk a butterfly shape.

There is a ciliated cup under the chin, just as im the two former species, but no
pellets are formed in it. I examined it carefully several times, but I could find no
lines of cilia between the chin and cup, such as Mr. Gosse observed in M. ringens ;
neither could I see the minute notches in the chin, through which, in that species,
minute atoms slip from the buccal funnel, to be conducted by lines of fine cilia to the
pellet cup.

The muscular, nutritive, secreting, and reproductive systems, are so similar to those
of MW. ringens as to call for no further remark.

Vascular System.—Leydig notices the absence of the contractile vesicle, and says
that he traced the two lateral canals from the corona, where they originate in two coils,
across the body, from the dorsal to the ventral surface, and so down to the cloaca. He
says that, after repeated efforts, he at last saw the two vibratile tags in the corona.
I was more fortunate, for I made out five vibratile tags on each side of the body, though
I could not see exactly where the lateral canals ended. I could find no contractile
vesicle, but on two occasions I noticed that the empty intestine became distended and
very transparent, and then shot out its fluid contents through the cloaca. While this
was going on, the passage from the stomach to the intestine was closed. It would thus
appear as if the intestine itself was filled by the lateral canals, and discharged the oftice
of the contractile vesicle. It will be seen subsequently that something similar takes
place in other Rotifera.

Organs of Sense.—I have failed to discover any eyes in the adult, but they are very
conspicuous in the young animal (PI. V. fig. 8b). The antenne are of great length,
twice as long in proportion as those of M. ringens ; and, as they are transparent, it is
easy to see how the muscle that runs up the centre to the setigerous knob at the top
can withdraw the knob, thus infolding the tube, till the knob comes right down to the
base of the antenna. When the animal is contracted into its tube, the antenne are closely
pressed to its elub-shaped body; and, as it rises, they, too, slowly rise from their
recumbent position, while the perivisceral fluid, under the pressure of the transverse
muscles, drives the knobs up the antenne, and so completely extends them.

The Male,-—I believe that the male Rotiferon drawn in Pl. V. fig. 3c, is the male of
M. tubicolaria. had a small piece of Anacharis with about a score of females attached
to it, and while observing them I saw this young male circling round one of them. It

74 THE ROTIFERA.

was about ,1, inch long; but, owing doubtless to its having just been hatched, the skin
was so granular and corrugated that I could not make out its whole structure. The
nervous ganglion, sperm-sac (ss), and penis (p), were plainly visible, and I could
see the motion of the spermatozoa, though not the individual spermatozoa themselves :
neither could I make out the muscles nor the water vascular system. I did not see
this creature hatched ; still, as there were no other Rotifera present but I. ringens and
M. tyro, it was certainly the male of one or the other.

The Rotiferon, I have little doubt, is Ehrenberg’s Tubicolaria Naias. He formed
the genus to receive a Melicertan that was destitute of eyes at all periods of its life,
and lived in a gelatinous tube. But Ehrenberg points out that he has not seen the
young, and that therefore the absence of eyes cannot be depended upon as a charac-
teristic. His other characters of the genus are, a four-lobed corona, two antennie, and
a gelatinous tube. Of these, the latter alone is peculiar to T'ubicolaria, and as it is not
sufficient to found a genus on, I have placed the animal among the Melicerte.!

Length. Adults from about =}; to +1; inch ; the maximum size given is that of Scotch
specimens. Habitat. Ponds and ditches, Birmingham (C.T.H.) ; Chartham, Kent (Col.
Horsley); Forfar (J.H.); Reading (Tatem) : rare.

M. Janus, Hudson.
(Pl. VIL. fig. 1.)
Qecistes Janus 5 A , A Hudson, J. Roy. Micr. Soc. 2 Ser. vol. i. 1881, p. 1, pl. i.

Upper lobes deeply divided, lower nearly confluent ; dorsal gap minute ; antennee
short; chin two-pointed ; pellets fecal.

This remarkable Rotiferon is one of those creatures whose form is as irritating to
the classifier as it is delightful to the naturalist. For it possesses in almost equal pro-
portions the characteristics of two genera, viz. of Melicerta and of Ci cistes, and might,
with nearly equal propriety, be placed in either genus. It was found first by Mr. J.
Hood in Loch Lundie in 1880, and was most numerous, and in best condition, on weeds
at a depth varying from six to ten feet.

When seen from the ventral surface, so that the lower lobes are partly hidden by its
tube, no one would suppose it other than a Melicerta; but when it turns and exhibits its
dorsal surface, it is seen that the lower portion of the corona resembles that of Gicistes,
for, instead of there being a wide dorsal gap in the ciliary wreath, there is scarcely any
at all (Pl. VII. fig. 1); and the subdivision of the lower portion of the corona is so
slight that the outline of its two lobes is almost confluent: in fact, it might almost be
said that this is a three-lobed Melicertan. As in Mcistes, thickenings (fig. 1d) cross
the corona, which itself is so thin that it becomes nearly invisible under dark-field
illumination, while the thicker portions stand out distinctly, especially when seen side-
wise (fig. 1b). When the animal begins to open its corona, these portions are thrust
forward in a squarish and very characteristic bundle, the thinner parts of the disk lying
folded neatly between them. In this respect M. Janus closely resembles Cicistes
umbella.

The cilia of the corona are unusually large, while the groove that les between the
principal and secondary wreaths is broad and deep. Should the larger cilia be checked
by contact with the side of the cell in which the animal is placed, it is easy to count
them, and their whip-like action becomes plainly visible. Individual cilia may now and
then be seen even in the secondary wreath.

The chin (fig. 1b, ch) is also peculiar. It terminates, not in one point, but in two

1 It must be admitted that Ehrenberg’s figure is very unlike mine. The corona is barely the width
of the body, and the antennw are very short; but I think that both disk and antenne are intended to
be represented in a contracted state.

MELICERTAD A. 75

(fig. Ie); and below it, at right-angles to it, are two thin walls (fig. 1a) looking like
the supports of a bracket, the chin being the bracket itself. These supports form,
with the chin above, and the ventral surface between them, a cup or recess somewhat
like the cup of MZ, vingens. I could not, however, detect any cilia in it. Below the eup is
a large viscous knob, as in the other species, but differing from them in bearing on its
upper surface two or more curved bristles (fig. 1b, h) pointing to the cup.

The tube is not nearly so compact as that of IM. ringens, or even of Limnias
ceratophylli. It is composed of large ovoid fiecal pellets, which are laid upon one
another somewhat obliquely in rings, as shown in fig. 2d.

The pellet is formed in the intestine (figs. 1b, 1c, 7), and when it is ready the animal
bends down over the cloaca (cl), the rectum (7) is everted and pushed forward, and the
pellet is shot over the shoulder so that it rubs against the viscous knob and is thus held,
partly by the sticky surface of the knob, partly by the curved bristles already mentioned.
When it has thus caught the pellet, the creature, with a swift twist backwards, pushes it
on to the top of its tube. The intestine (7) is large and usually contains a fiecal pellet
in the course of formation. These are not all appropriated to the construction of the
tube, but are often suffered to float away. The gastric glands (gg) are conspicuous,
and form an arch over the top of the stomach: they contain large nucleated cells.
The two ventral antenn (a) are short and are placed rather as they are in an Ccistes
than in a Melicerta. Mr. Hood tells me that he has seen the male, and that it resembles
that which I have figured as the male of M. tubicolaria. He further notices that the
young female acquires its perfect form in four days after it has been hatched. Although
M. Janus has so many points in common with the genus Wcistes that I originally placed
it there, yet as it really has four lobes in its corona (however inconspicuous two of them
may be) I have felt constrained to add it to the Melicerte.

Length, ,!; of an inch. Habitat. Lochs only, Forfar, Perth, Ayr (J.H.): abundant.

Genus LIMNIAS, Schrank.

GEN.CH. Corona distinctly of two lobes ; dorsal gap wide ; dorsal antenna minute ;
ventral antenne obvious ; tube without pellets.

The genus Limnias differs from Melicerta in the shape of its lobes, and the structure
of its tube. The corona is much broader than it is high, and consists of two nearly
circular lobes connected on the ventral side by a hollow opposite to the buccal funnel,
and separated on the dorsal side by a gap. The double ciliary wreath, buccal funnel,
and chin are similar to those of Melicerta. There is no ciliated cup, though there is a
hollow beneath the chin somewhat like one.

The tube is unlike that of Melicerta or Gicistes ; it is really tubular in form, widen-
ing a little towards the top; it is often opaque, and is not composed of pellets; those
of the different species are unlike each other.

The internal structure of the common species, 1. ceratophylli, is almost precisely
that of Melicerta: it is said by Ehrenberg, and often repeated, that it has no vascular
system, but this is a mistake. I have seen, but have not had an opportunity of study-
ing, the rare species L. annulatus ; neither have I been able to find any account of its
internal structure.

L. CERATOPHYLLI, Schrank.

(Pl. VL fig. 1.)

Limnias ceratophylli. : Ehrenberg, Die Infus. 1838, p. 402, Taf. xlvi. fig. 4.
” ” 3 , : Gosse, Evenings at the Microscope, 1859, p. 302, with fig.
” oF ; c 7 Pritchard, Infusoria, 1861, pl. xxxii. figs. 388-392,
pl. xxxvi. fig. 2.
Melicerta ceratophylli. ‘ : Gosse, Popular Sci. Rev. vol. i. 1862, p. 481, pl. xxvi. fig. c.

Limnias ceratophyli . . Moxon, Trans. Linn. Soc. vol. xxiy. 1864, p. 458,
pl. xlvii. fi 3.

76 THE ROTIFERA.

Limnias ceratophylli : Tatem, J. Queketi Micr. Club, vol. i. 1868, p. 124,
pl. vi. figs. 1, 2.

Limnias socialis . s ° . Leidy, Proc. Acad. Nat. Sci. Pa. 1874, p. 140.

Limnias ceratophyli. - : Bedwell, Mon. Micr. J. vol. xviii. 1877, p. 221, pl.

exeviii. figs. 7, 8.

SP. CH. No horny processes on the dorsal surface below the corona; ventral antenne
very short; tube nearly cylindrical, smooth, often rendered opaque by extraneous
materials, except at the posterior end.

Ihave already related, in Chapter I., Leuwenhoek’s discovery of this the earliest
known tube-maker. It has not been much studied, as its tube is often quite opaque, and
its own attractions have been eclipsed by those of Melicerta. The tube is of a yellow-
brown tint and is generally coated over on the outside with waste matter that falls
down on it from the coronal currents above, and with the particles that trickle over the
chin, and adhere to the sticky surface beneath it. These latter are rubbed off from time
to time on to the tube by the animal, as it bends its head over it. Doubtless this
renders the tube smooth and compact. Judge Bedwell (loc. cit.) thinks that there
is a chitinous shield below the dorsal gap, whose hard edge is shown at @z, fig. 1d.
He points out that its position corresponds to those of the horny processes of L. annulatus,
and the sharp hooks of MW. vingens; and he suggests that the tube is smoothed with it
“much as a bricklayer smooths over his stucco with his flat trowel.” The tube is
generally not coated towards its posterior extremity, and is very imperfectly covered in
the young (fig. 1g). Occasionally adults are met with that have tolerably transparent
tubes,' and even large adults have sometimes tubes of an opaque white (fig. 1b).

Ehrenberg recognises no vascular system,? but Dr. Moxon (loc. cit.) has observed
part of it, and given a figure of the neck and expanded corona, with two vibratile
tags on the same side. I have had no difficulty in seeing the lateral canals, and
their accompanying tags, in the upper portion of their course, from a vascular plexus
near the shoulder, up to a similar one in the corona (fig. 1f, lc, vt). The contractile
vesicle (if there is one) has not yet been noticed.

Besides the two short ventral antenne (Pl. VI. figs. 1d, 1f, a) Dr. Moxon (loc. cit.) has
observed a minute dorsal one similarly situated to that in MW. ringens.

Prof. Leidy (loc. cit.) says that im many localities of the Schuylkill, almost every
stone exhibits multitudes of bunches of a Limnias, pendent from its sides, and under
surface: as many as fifty tubes may be counted in a bunch. Prof. Leidy proposes to
call this rotifer L. socialis, on account of its habit of growing in clusters; but as the
animal itself is said to be like LZ. ceratophylli 1 other respects, and as L. ceratophylli
in England has this habit of clustering to a considerable degree * it is unnecessary to
make a new species of the American Rotiferon.

Male. [As a Limmias was slowly protruding from its tube, there swiftly pushed
past it, out of the mouth of the tube, a young one, which I supposed from its general
appearance, a male.4 It was a simple cylinder of colourless flesh, slightly tapermg be-
hind to a blunt point, with no foot or tail apparent, of about one-third of the total
length of the parent, filled with minute globules of oil or air. There was a simple
crown of cilia around the truncate front, a well-sized and well-made mastax, an enor-
mous blunt-pointed brain-sac reaching about two-thirds down its total length, and
carrying, on its dorsal side, near its point, a small but clear round eye-spot of crimson
hue. Its manners were those common to males, swimming swiftly around the parent,
often coming close to her for a moment, and then darting finally off on a wide wild
voyage. That this was truly a male individual of the species is highly probable, not-
withstanding the presence of a mastax, of which there was no doubt, and of a long
viscus below which appeared to be a stomach. P.H.G.]

Length. Maximum about ,'; inch. Habitat. On water plants: very common.

1 Mr. Gosse (loc. cit.), p. 303. 7 « Kiemen und Gefiisse sind nicht erkannt.”
3 See p. 38; Pl. VI. fig. le. 4 -P]. D: fig. 7.

MELICERTAD A. 77

Mr. Tatem (loc. czt.) described and figured a tube-making Rotiferon, somewhat
resembling a Limnias, with long curved antenne. If the bi-lobed condition of the
trochal disk (as given in his figure) were permanent, and if there were also an obvious
dorsal gap in the ciliary wreath, this would be a species of the genus. Unfortunately
My. Tatem’s description does not make this point clear, and in other respects the animal
resembles Gcistes longicornis.

L. annutatus, Bailey.
(Pl. VI. fig. 2.)
Limnias annulatus . : + 3 Cubitt, Mon. Micr. J. vol. vi. 1871, p. 165, pl. xeviii.

SP. CH. Five horny processes on the dorsal surface below the corona; ventral
antenne moderately long; tube cylindrical, smooth, transparent, and crossed by trans-
verse ridges, at regular intervals.

I have met with this Limnias but once, and then had no time to study it. It
appears to be rare in England, though Mr. Cubitt (from whose paper, cited above, the
following particulars are taken) found it in abundance in a tributary of the Northbourne
Brook, Kent.

Its tube is remarkable. In young adult specimens it is perfectly transparent, with a
brilliant orange tint which at the sides becomes a deep carmine, owing to the greater
thickness of tube which we there look through. Fine transverse ridges, one-ten-
thousandth of an inch apart, surround the tube from top to bottom. These are possibly
caused by the pressure against the case of two horny processes (figs 2b, 2d, hp)
on the dorsal surface. These, under dark-field illumination, show a bright red spot
at the top. Three less prominent processes lie in a line below the first two ; the distance
between the rings is precisely that between these two rows, so that possibly they may
help to form and gauge them.

The foot is long, wrinkled, with distinct muscles. When the animal contracts itself
into the case it folds the foot as shown in fig. 2a; a plan also adopted at times by L.
ceratophylli.

Length, ;'; inch; Scotch specimens, ,, inch. Habitat. Witlingham, Norwich
(Brightwell) ; Kent (Cubitt); Forfar (J.H.): rare.

Genus CEPHALOSIPHON, Ehrenberg.
-GEN. CH. Corona nearly circular; dorsal gap distinct ; dorsal antenna obvious ;
ventral antenne absent! ; two dorsal hooks enclosing the dorsal antenna.
C. urunias, Hhrenberg.
(Pl. VI. fig. 3.)

Cephalosiphon Limnias . , F Ehrenberg, Verhandl. der Berlin Akad, 1853, p. 193.
as a c 2 ; Pritchard, Infusoria, 1861, p. 670.
Limnias ceratophylli. i ‘ Slack, Marvels of Pond Life, 1861, p. 149, with fig.
Cephalosiphon Limnias . : : », Intellectual Observer, vol. i. 1862, p. 53, figs. 1, 2.
i a 3 = Gosse, Intellectual Observer, vol. i. 1862, p. 49, with plate.
Melicerta Cephalosiphon . 5 ~ » Popular Sci. Rev. vol. i. 1862, p. 490.
ss 5 : . 3 Tatem, J. Quekett Micr. Club, vol. i. 1868, p. 124,
pl. vi. figs. 6, 7.
55 6 ° 3 5 Cubitt, Mon. Mier. J. vol. y. 1871, p. 170, pl. Ixxxi. figs. 1, 2.
a FY) : : cs Hudson, Mon. Mier. J. vol. xiv. 1875, p. 165, pl. exvii. fig. 1.

SP. CH. Dorsal antenna very long ; tube tapering to the foot, compact, strengthened
with extraneous material.

' I thought once that I caught sight of a minute setigerous yentrally placed pimple in C. Limnias ;
there may possibly be a pair of such ventral antenna.

THE ROTIFERA.

~I
io 2]

Ehrenberg formed the genus Cephalosiphon of his family of the F'losculariea to receive
a single species, C. Limnias, one specimen of which he found on Ceratophyllwm at Berlin.
His characters of the genus are as follows: ‘‘ Cephalosiphon, E. Rotatory organ bi-
lobed, eyes two, sheath or lorica single, two little frontal horns enclosing the siphon; ”’
and those of the species are: ‘ C. Limnias, HK. Sheath membranaceous, ringed.”’

The characters of the genus and species were given in Pritchard’s ‘ Infusoria ”’
(edition 1861), but no one after Ehrenberg seems to have actually seen the animal itself,
till Mr. Slack found it in a pond in the neighbourhood of London in 1860 on Anacharis
alsinastrum. My. Slack supposed it to be the young of Limnias ceratophylli, and gaye
a brief description of it under that name in 1861 in his ‘‘ Marvels of Pond Life ’’ (doc. cit.).
He noticed the creature’s bi-lobed corona, as well as the great length, flexibility, and
peculiar action of the dorsal antenna “ thrust on this side, and on that, as if to collect
information for its proprietor.”” Mr. Gosse in the same year, in a paper entitled “ A
Rotifer new to Britain (Cephalosiphon Limnias),” gave a full description with a plate
of three figures of the new Rotiferon, taken from some specimens sent to him by Mr.
Slack. These specimens seem to have been injured by the journey, as they did not
expand freely, and so led Mr. Gosse to draw the corona with a butterfly-shape, which
healthy specimens do not possess. Mr. Gosse, however, fully worked out the Rotiferon’s
structure, with the exception of the secreting and vascular systems ; and he described
and figured the ‘ frontal horns’ or hooks, which are situated like the hooks of Melicerta
ringens, one on each side of the dorsal antenna. This Rotiferon is very partially dis-
tributed. It was upwards of twenty years after I first began to search for Rotifera in
the neighbourhood of Clifton, that I first lighted on it; and Miss Saunders has had a
similar experience at Cheltenham. In 1875 I found a group of them on a leaf of a
Potamogeton in a pond at Nailsea, near Bristol, and I made a careful drawing of the
group (PI. VI. fig. 8). The tube is horn-shaped tapering to the foot; generally neater
and more compact than that of Gicistes crystallinus, but coated with much the same
sort of yellow-brown material.

The trunk is small compared with the foot, which is long and slender. The animal
urches its dorsal side (fig. 3), in a manner common among free-swimming Rotifera, but
unique among the fixed ones, which, in all other instances, arch the ventral side, so as
to bring the entrance to the buccal funnel uppermost. C. Limnias has that entrance
a'most hidden by the bending over of the corona. The arrangement of the double ciliary
wreath is precisely that of the other Melicertade. The usual pair of clear vesicles
( salivary glands ? ) rest on each side of the top surface of the mastax, which is high in
the neck towards the dorsal side ; and the ciliated buccal funnel slopes across to pass
between them. There are a narrow cesophagus, two globular gastric glands, cylindrical
stomach, short intestine with upturned rectum, ending in a cloaca rather low on the
dorsal surface.

Of the vascular system nothing has been seen; but Mr. Gosse (Joc. cit. ‘ Intell. Obser.’’)
describes the nervous ganglion as ‘a grey cloudy mass of irregularly-lobed form, imme-
diately below the antenna, and behind the discal mammilla.”” I thought once or twice
I caught sight of a ventral setigerous pimple just below the entrance to the buccal fun-
nel, but I am not sure about it: there may be a pair of them there. The dorsal antenna
is the striking feature in C. Limnias. When the animal has closed its corona and retired
into its case, this slender transparent rod, with a brush of sete at the top may be seen
gently moving about to see if the coast is clear. When satisfied that it may come up
safely, Cephalosiphon hitches its long antenna over the side of the tube, and hoists
itself up by it into a great curve; it then straightens its body and unfurls its corona.

The long antenna is not always straight ; it is occasionally bent into long curves like
the process of [’. cornuta, but its changes of form are slow. Its base is broadened out
like that of a rose-thorn, as if to give it a good purchase. Two red eyes are conspicuous
in the adult, a little below the dorsal surface, one on each side of the antenna, and close

to the nervous ganglion.

MELICERTADA, 79

The gradual changes of form in the young are shown in figs. 8, 2, y, z, which
are all taken from the same individual in different stages of growth. Fig. 3, 2, shows
it when only 5}, inch long, and with a sort of hump where the dorsal antenna is to be.
Twenty-four hours after, the hump had become a short antenna (fig. 8, y); in four days
the young animal had grown to ‘5 inch, in six days to 2; inch, and in twelve to =; inch,
by which time, as shown in fig. 8, z, the characteristic antenna was well developed: at
this stage of its growth I unfortunately lost it.

I have little doubt that M. du Trochet was the first discoverer of C. Limnias. In
the “‘ Annales du Muséum d’Histoire Naturelle,” t. xix. 1812, p. 885, pl. 18, figs. 19 to 21,
he describes and figures a tube-maker, Rotifer cruciger, with a fawn-coloured tube and
a long dorsal antenna, and he noticed that the animal explores with it in all directions.
It is true that he figures two eyes, ‘ saillants et globulaires,’ near the summit of the
dorsal antenna, one on each side of it; but these (if the animal were C. Limnias) must
have been something extraneous, accidentally attached to the antenna ; possibly two air-
bubbles.

Length. About ,, inch. Habitat. Neighbourhood of London (Mr. Slack); Sand-
hurst, Berks (Dr. Collins) ; Woolston, near Southampton (P. H. G.); Cheltenham
(Miss Saunders) ; Lochs, Forfar (J. H.); Nailsea, near Bristol (C. T. H.): very partially
distributed.

C. canpipus, Hudson, sp. nov.

SP. CH. Dorsal antenna very long ; tube irregular, semitransparent, gelatinous.

Mr. J. Hood found this very rare Rotiferon in Loch Lundie in October 1880, and again
between September and December in the same loch next year. He found a few speci-
mens in his aquarium, but evidently from eggs on weeds brought from the same spot.

Mr. Hood points out that it differs from C. Limnias not only in its tube, but also in
its stout wrinkled foot, which is kept habitually in this condition. I have always noticed
that the foot of C. Limmnias (when in its tube) is delicate, tapering, and smooth ; but Mr.
Gosse found that, on his dislodging one from its tube, the foot became of nearly equal
thickness throughout (as in C. candidus), and of about one-third the diameter of the
body, from which it was abruptly separated. The whole length, too, was then studded
with wrinkles, which at intervals took the form of great thickened rings. The foot termin-
ated in a circular sucking disk. The two species are very much alike; but their tubes
differ so much that I have thought it best to keep them apart.

Length, ,j; inch. Habitat. Loch Lundie (J.H.): very rare.

Genus (CISTES, Lhrenberg.

GEN. CH. Corona a wide oval, indistinctly two-lobed; dorsal gap minute ;
dorsal antenna absent! ; ventral antenne obvious.

In this genus the tube is extremely irregular and variable in shape ; it is usually
of a loose fluffy texture, and encumbered with extraneous matters of all kinds. In one
species, however, it is compact, like that of Limnias ceratophylli; in another it is
formed of fecal pellets ; and in a third it resembles that of Melicerta tubicolaria.

The corona is no longer distinctly lobed, and becomes nearly cireular ; it is hollowed
a little on the ventral side opposite to the buccal funnel. The ciliary wreath is double,
and is on precisely the same plan as that of the preceding genera; only the dorsal gap
in it, though distinct, is so minute as easily to escape notice, unless the animal be in a
favourable position. Ehrenberg failed to see either it or the secondary wreath; and,

' Probably a minute sctigerous pimple, which has escaped observation,

80 THE ROTIFERA.

in consequence, separated it from the Melicertade, and placed it in a family named
after itself: an honour it did not deserve. The antenne vary greatly in length in the
different species : some are mere setigerous pimples, others the longest known among the
NRotifera.

The internal structure, so far as it has been ascertained, is that of Melicerta. The
parts not made out are the vascular system and the nervous system. ‘The male also is
unknown.

Gh. crystanuinus, Hhrenberg.
(Pl. VIE. fig."3:)

cistes crystallinus , a C Ehrenberg, Die Infus. 1838, p. 392, Taf. xlii. fig. 7.
” ” . c é Pritchard, Infusoria, 1861, p. 663, pl. xxv. figs. 361-364.
Melicerta crystallina : . 5 Gosse, Popular Sci. Rev. vol. i. 1862, p. 490.

SP. CH. Ventral antenne extremely short, and set wide apart ; tube most variable
and irregular in shape, often beset with extraneous matter.

I have frequently met with this Rotiferon in dense colonies, whose dirty-brown tubes
gave quite a rusty look to the water plants which they infested. Though small, it is a
very pretty object; and, with a little care, the secondary wreath of cilia, the two
antenne and the dorsal gap in the ciliary wreath can be distinctly made out. For this
purpose the animal must be so placed that its long axis is nearly in the line of sight.
From almost all other points of view the dorsal gap is invisible, and only one antenna
can be seen at once, owing to the unusual width between the two. When the case is
free from rubbish, it is not difficult to see that the animal’s internal structure is very
like that of Melicerta. The vascular system and the nervous system have not yet been
observed. ‘Two red eyes are visible in the half-crown young.

Length. About ;!, inch. Habitat. Ponds and ditches: very common.

50

(3. INTERMEDIUS, Davis.
(Pl. VIL. fig. 5.)
Meistes intermedius ; F ; Davis, Trans. Roy. Micr. Soc. vol. xy. 1867, p. 14, with fig.

SP. CH. Antenne short; dorsal gap wnusually wide; tube opaque, tapering
slightly from top to bottom.

Mr. Davis found this species at Leytonstone, in company with the former. It
differs from Gf. erystallinus in the width of the dorsal gap in the ciliary wreath, which
almost approaches that of a Limiias, and in its neat tube, which exactly reproduces that
of L. ceratophylli. In fact, had it not been for its distinctly oval corona, I should have
said that it was a variety of the latter species. Mr. Hood, however, tells me that he has
found it (sometimes in abundance) in Scotland and always with the oval disk ; Mr. Gosse,
too, has seen many Scotch specimens, and has no doubt that it is a true species.

[Two specimens, so young that no visible tube was begun, yet attached to a stem by
the foot, showed, in the wall of the occiput just below the ciliary rota, two well-defined
and conspicuous dark eyes, rather far apart.—P. H. G.]

Length. About ;!; inch. Habitat. Leytonstone, Essex (H. Davis); marsh pools,
Vife and Perth (J.H.): not common.

CE. SERPENTINUS, Gosse, sp. nov.
(DENG IDs iateg IA)
SP. CH. Corona small, circular ; foot fully thrice the length of the body, much

wrinkled, extensile ; ventral antenna a single, simple tubercle ; a pair of dorsal hooks
below the corona, adnate at the base ; tube very short, or absent.

4

Wi

oa

an =
om ie = Ae
4 H
” es
~—
oo .
l= 2

1.
2.
3.
3a.
3b.
4,
4a.
4b.

9a.
10.
Une

Floscularia campanulata

Floscularia Cyclops c
Acyclus inquietus . :
” ” Ld e

9 ” . .
Apsilus lentiformis . :
7 3 ¢

” ” ° ©

” ” . e

” ” . .

” ” _ hi

” e .

Apa bipera a “

” ” . . .
Melicerta conifera . '
3 x) : 5
Limnias ceratophylli.
Cicistes velatus . 4
- °F ‘ 3
” ” ° '~
” ” ® J
” ” O v
” ” ° -,
” ” . .

Megalotrocha alboflavicans

” ” *

Conochilus volvox . 0
Trochospheera sequatorialis

PLATE D.

with everted tube (after Dr. Moxon)

ventral view . a 4 6 O 5
side view 5 A 5 5 ‘ 6
head, ventral view 0 A fs :
head, closed, side view . 4 . .
dorsal view . 0 5 , : F
ventral view, contracted 9 ; 5
nervous ganglion, lateral canals, and
vibratile tags. : 5 : 9
trophi . 5 . , . . :
young female, dorsal view . 5 :
male, dorsal view . 5 0 F d
hind extremity of male . : . :
ventral view . dl 5 : q :
head, dorsal view, showing ciliary
wreath 4 ; ; 5 : :
male coming out of tube 0
male, side view . ; 5 Z ;
male ; : A 4 . .
side view; corona expanded . 5
side view; corona contracted 5 °
corona, side view, showing thickenings .
foot and sucker. ; 5 3 3
cloaca, and surrounding parts : :
mastax, front view 4 a 6 F
mastax, side view . é P E
young female . : 5 : :
young male (?)_.. . 5

male, dorsal view (after Dr. Cohn)
female, side view (after Prof. C. Semper)

:
:

5 Jal

after Prof. Leidy.

after El. Metsch-
nikoff

after Miss Foulke

NAMAQDAANAADAMD

oF

“STIVIMOLVNOY VEYHHASOHOOUL Il XOATOA SN TIHOONOD ‘OL

a er. Cee TTT AT
ITTAHGOLVEAO SVINWIT 2

SNYOLIAVIAOGIV VHOOMLOTVOING SNLVIZA SALSIOM @
‘Vauddid SNTISdVS SINMOFIINAT SNTISdV? SNISINONI SNIDAOVE SdOTOAO VIEVTNOSOTA

dunt acemey

2
G

aadINOO VIEAOITAW 9
VIVINNVGAYO VIEVTNOSOTd

{° #8009 7.d"6%9
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=

-

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ule
la.
1b.

2d.

3a.

Limnias ceratophylli

”

”

Limnias annulatus

”

”

Cephalosiphon Limnias

”

”

”

”

”

”

”

”

PLATE VI.

ventral view . ; 5 0 ¢ 3 5 5 Jal
side view; corona contracted ; 5 H
side view; corona expanded . . 5 3 ay JBL
a cluster of tubes . a é 7 . cs o dat

head, side view; zwedgeofchitinous ) after Judge

plate . a a a fi 5 4) Bedwell
buceal funnel, mastax and cesophagus . A 5 Gr

head and neck; ventral view showing vascular
system a di : a 0 . : >
Ef

young femalé, dorsal view. . 6 - A .
ventral view . 0 3 5

side view; retracted . 5

head; dorsal view . : 4 . after Mr. Cubitt
head; seen from above . . ‘

head; corona contracted 0 ;

group: @, y, 2 successive stages of growth . 5 BE
dorsal view . 5 . : 5 ; , 5 dal
ventral view . : : , 4 r : 5 lel

PL VI.

toon

1. Melicerta Janus

la. ry on
1d. 7 “
le. 7 _
1d. ca os
le. mr p
if. ” ”
2. Cicistes pilula
2a. re 6
2b. a PS
2c. 1D 1
2d. - a

3. Cécistes erystallinus
4. Cicistes umbella

4a. 7 p ;
5. Cicistes intermedius
ba. ” ”

6. Ccistes longicornis

PLATE VII.

dorsal view. :

obliquely ventral view :

side view; corona expanded . J ;

side view; corona contracted .

corona, showing thickened portions.

cleft extremity of chin .

a ventral antenna .

obliquely ventral view

obliquely dorsal view .

side view; corona contracted .

young female; dorsal view

ring of pellets from the tube

obliquely ventral view

dorsal view

obliquely ventral view

adult; side view . < |

young; dorsal view; corona ; after Mr. H. Davis
contracted J

side view . 5 5 5 : : : : 5 BE

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¢-VITGTENN DF SANITIVLISAHD De VIN Ds “SONVE WI

‘SINHODISNOTD 9 ‘SHIGANUAINI O°
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dan qaeyuey

PLATE VIII.

1. Lacinularia socialis ; . dorsal view : ; $ : 5 ‘4 5 dal
la. A astlate 5 . side view . 131
1d. f ee 0 + group H
Ve: PA Ht 0 A . male; side view H
1d. eee . penis . : H
2. Meealotrocha alboflavicans . dorsal view ; : , ‘ , ¢ EL
Qa. 7 we . side view . 5 < : H
2b. An la . ventral view; corona expended 5 H
2c. " po . ventral view; corona contracted é 3 5 Jel
8. Conochilus volvox . : . side view . 5 : 5 H
ba. ry oh j . ventral view H
3b. or Us F . dorsal view ; ; A ‘ 3 : jal
8c. a Par , - obliquely ventral view H
bd. same ‘: . male; side view 3 ; 3 3 H
Be. 7 mo 5 . cluster 6 . c ; 5 : , 3 1BL
Bf. 1 0 7 . cloacal opening : : . : : H
3g. 5 hc : . antenne . 9 5 9 H
Bh. ; ah) <o : . eye . 5 5 H
Bu. Sy st as i ‘ showing Salih of lateral Gana anil clones H
Bk, 3l, 8m, 38n. ae : . successive stages of ephippial egg. lal
3p. i, ‘ - male in egg ‘ : : 5 ‘ ; 5 (1EE
Bq. is ate ‘ . spermatozoa ol nice Die, Gana

Br. = 5 ‘ . spermatozoa attached to ovum. }
4, Conochilus dossuantus : . obliquely dorsal view ; c : : eal

= y
f # i
iv ,
|
il iv ‘ +
1
I i
i
= =
/
1
: ‘
i
r
i
4
H
i
t
a
i
il
it
i
i
i
1
i
'
1m

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=

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vee eg

”

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t

elt

oniuwnss0d'9% XOATOA 9 ¢ SNVOIAVIAOETV NZ SITVIDOS TI
°SATIMDONOD ‘VHIOULOTVO TA sVIUVIONIDVIT

jap ata pe vospny LO

Tea ’
i

ny

1. Qcistes serpentinus .
la. ” ”

1b. ” ”

2. Cicistes brachiatus
2a. 3 a

2b. Po i

2c. ” bay

2d. ” ”

3. C£cistes Stygis .

4. Philodina roseola

4a. aN p

4b. 3 3

4c. ” ”

4d.

Ds rDhattgittan nonlont
5a. ” ”

5b. ” ”

5e. ” ”

5d. ry)

6. Philodina isa
7. Philodina Serene
Ta. H ”
7b. 5 y

PLATE IX.

side view
side view, contracted ea a amaller ental)
head; showing the hooks : é

dorsal view

upper portion, pepandede aide view
upper portion, contracted 0

extremity of an antenna

extremity of foot, showing peduncle
dorsal view . :

dorsal view ; corona expanded

dorsal view ; corona contracted

side view 5 d
dorsal view ; contracted fate a a ball
transverse muscles shown under pressure
side view; corona expanded . é

side view; corona contracted

dorsal view; hiding the foot .

column partly retracted; and antenna .«
dorsal view in outline; showing the spines
dorsal view

dorsal view . : 9

side view

dorsal view ; contracted .

RRAARARAAARRARAAARAVQARQAAA

= 5

VHOOMLOTVOIN dL “VNIELIOd 9 ‘WIVAZINOV ds “VIOHSOU dt
SIDAIS DE “SNLIVIHOVHE D ¢ ‘SNNILNGdxaS

po es
oUF RT TAT MT a
¥ NICO TWHd

hat JUeYULY

tp ATA pr as Sood

by,
‘

Pre ge hy es
as Dae OS Tene

—_—

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hin
1) oy

i
)

gajehhor |
iA aire aE

VWs

th
Wiig

ih) ()

i!

ee

tetpana’

-
l=
me

*

( ’ ,
j : 2
= :
ee
7
;
i
°
pi
f
2
\
| ;
oe

1. Rotifer tardus .

la. + mn 5

1b. * rs

le. rr ve A A
Nass 5 :
le. » FH 5
2. Rotifer vulgaris.

Qa. a Pe é A
26. 9)

3. Rotifer hapticus
4. Rotifer macrurus
4

a. y ”
4b, 4c. ,, oa a
5. Rotifer megaceros

5a. wl 6

5D. * Won

6. Actinurus Neptunius .
6a. ” ”
7. Callidina bihamata

Ta. % fy '
Tb. 3 55

ies % ”

8. Callidina bidens

8a. a a

8b. a6 iy

9. Callidina parasitica
9a. A H 7
9b. fs as .
9e. 7 a ‘
9d. fs Ee ;

10. Adineta vaga
10a. By -F
10d. 5 7
10c. or Mm

PLATE X.

dorsal view; corona expanded

dorsal view; corona contracted

side view 3 : : : .

head; side view; corona expanding. A
mastax and alimentary canal (under pressure)
column with the eye spots broken up .
spurs and toes ¢ c : : ¢ :
dorsal view; corona expanded

dorsal view; corona contracted

spurs and toes é

side view : : : : :

dorsal view; corona contracted .

obliquely dorsal view ; corona expanded

spurs and toes é a 3 : .
dorsal view .

side view - 7 3 : :

dorsal antenna . é 5

side view, extended ‘ 5 6 :
dorsal view, contracted . 5

dorsal view . ; * - . : 5
side view , ‘ . 5 : ‘:

column and hooks, dorsal view.
column and hooks, ventral view .
dorsal view; corona expanded :
dorsal view; corona contracted .

dorsal view, retracted . 5

dorsal view; corona contracted . g
dorsal view, retracted . 3 5

head, dorsal view; corona expanded

trophi_ . 6 : 3 5 : 6 a
penultimate joint and spurs . 3 3
ventral view . : 5 : : F F

head, side view (after Mr. H. Davis)
ovary, lateral canals, and vibratile tags
trophi_ . 6 é : : : . .

qe TH ADAAMRAARARARAARARAARAARAARARAARAAD

—s -YOVA VO VoOILISVadvd 06 ‘SNaZdId OS ‘VIVNWVHIG OZ ‘SOINOLAAN V9
“SOuaOVOSIN US ‘SnunUuovN ay ‘SNOILdVH WE ‘SIuVOTOA Ue ‘SNCaVL cine
uospny LE) ‘OL

. ° § $ -
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MELICERTAD AS. 81

[This very striking species I found on leaves of Anacharis alsinastrwm, which had
been growing for months in a glass jar in my study-window.

The body and corona do not vary much from those of other species. In the act of
expanding, the summit of the head becomes sub-conical, and is seen to terminate in two
small hooks having a common stem, which remind the observer of the protruding head
of Melicerta ringens (fig. 1b). When unfolded, the corona does not much exceed
the greatest diameter of the body: it appears to form a complete uninterrupted circle.
A small round knob on a conical eminence constitutes a ventral antenna; a little
below which is seen the mastax; and, about as much below this, but on the opposite
side to the antenna (the dorsal side), the cloaca is bounded by a minute wart. The body
is of the usual proportions, but the foot is of enormous length, being about thrice as long
as the trunk and head. It is rather stout (about half the greatest diameter of the body),
and of uniform thickness throughout; thrown for its entire length into transverse
close-set wrinkles. These were not obliterated nor perceptibly diminished by the
greatest extension that I witnessed; so that, if this corrugation is a provision for
indefinite elongation at pleasure, as one must suppose, then the foot would seem capable
of stretching to a length more than ten times as great as I have represented! Yet I have
seen it on repeated occasions contracted in an instant to a condition in which it was not
more than half the length of the body, or one-sixth of its former length.

The investing tube is reduced to extreme insignificance. The one that I saw would
not hold half the body, even if it had no foot. It was invisible, save for a few
irregular opaque masses here and there, and for two or three eggs adhering to the
margin. As if indifferent to concealment, the foot was attached to a point not near the
bottom of even this short dwelling.

The trunk is transparent, but tinged with umber-brown. Here and there, within,
were multitudes of very small air- (or oil-) globules agglomerated into long masses, which
looked like patches of blue-black hue, and had a curious appearance. When I first saw
the specimen, two egg's were already laid, and presently a third was added, but not under
my actual gaze. The eggs were allof a clear yellow, minutely granular.

The manners of this creature are as odd as its figure. It is not by any means in-
tolerant of exposure: though sensitive, shutting up and violently contracting on a very
slight shock or jar, yet in a moment it is again stretched to its length, and quickly has
its corona expanded. The foot is endowed with an extreme flexibility and muscular
power, for the animal is constantly (I will not say swung, but) shot, from side to side ;
just as the body of a snake or of a writhing worm is jerked about in tortuous evolutions.

While I was examining and delineating this example, another appeared, in all essen-
tial points agreeing with it, but quite destitute of any apology for a case, the foot being
unattached to any object; the creature being loose in free water, but lying on the same
leaf of Anacharis. The male has not yet been observed.—P.H.G.]

This species in many points resembles Ehrenberg’s Piygura Melicerta. The two
agree in the small corona, cylindrical body, dorsal hooks, single ventral antenna, many-
toothed jaws, and inconspicuous or absent tube. But the prodigious length and ex-
tensibility of the great ringed foot of G7. serpentinus, and the animal’s extraordinary
actions, none of which are mentioned by Ehrenberg, show it to be a different creature.
If Ehrenberg had geen only a solitary specimen for a few minutes, in a contracted
state, the two might have been supposed to be the same ; but he distinctly says that he had
met with many examples. Besides, Herr Eckstein has also found Ptygura Meliccrta
more than once; and, although he has not seen the expanded corona, his description
and figure in all other respects agree with Ehrenberg’s.

From the descriptions given by Ehrenberg and Herr Eckstein I am inclined to think
that Ptygura is an Gcistes; but it is impossible to determine this till the corona has
been thoroughly studied.

Length. Not recorded. Habitat. On a leaf of Anacharis alsinastrum in a fresh-
water aquarium (P.H.G.).

H

82 THE ROTIFERA.

(i. LOoNGICORNIS, Davis.
(Pl. VIL. fig. 6.)
Gcistes longicornis 5 . ; Davis, Trans. Roy. Micr. Soc. vol. xv. 1867, p. 13, with figs.

SP. CH. Antenne very long and recurved ; tube floccose, wreqular.

Mr. H. Davis found this well-marked species, in abundance, in ponds at Leytonstone,
Essex. It is the smallest of the tube-makers. The tube is very irregular and variable
in shape; but, in most of the examples which I have met with, small and tubular at the
bottom, while wide and unsymmetrical towards the top. On supplying it with carmine,
Mr. Davis saw that the fine coloured particles accumulated in the hollow under the chin,
and that they were then rubbed off by the Rotiferon, and left on the top of its case. He
thus obtained tubes with crimson tops at least one-fourth of the length of the whole,
showing how the structure was gradually formed. The long antenne, curved back from
the ventral surface, and set wide apart, give this (icistes a very striking appearance.

Length. About, inch. Habitat. Leytonstone, Essex (H. Davis); Abbot’s Pond,
Clifton (C.T.H.) ; Woolston, Cheltenham (P.H.G); marsh pools, Fife and Perth (J.H.,
P.H.G.): partially distributed.

i. prnuna, Wills.

(Pl. VIL fig. 2.)

Melicerta, variety No.2 . . é Tatem, Jowr. Quekett Micr. Club, vol. i. 1868, p. 124,

pl. vii. figs. 3, 4.
Melicerta socialis (?) é 0 ; Collins, Science Gossip, No. 85, 1872, p. 9, with fig.
Melicerta pilula (?) . 2 : ; Cubitt, Mon. Mier. J. vol. viii. 1872, p. 5, pl. xxiv. figs. 2-4.
Zeistes pilula : . 4 5 Wills, Midland Naturalist, vol. i. 1878, pp. 302, 317,

pl. v. figs. 3, 4.

SP. CH. Antenne long ; tube formed of fecal pellets.

The first certain notice of this Rotifer is by Mr. Tatem (loc. cit.). He gave two ex-
cellent and characteristic drawings of it ; saying merely that it was a two-lobed variety of
Melicerta ringens, without a ciliated cup, and inhabiting a ‘“ gelatinous sheath’ with ad-
herent fecal pellets. Its broadly oval! corona, however, and the minuteness of the
dorsal gap in the ciliary wreath, clearly place it in the genus Wcistes.

As in Melicerta Janus, the intestine is large and densely ciliated ; and nearly always
contains an oval pellet in the course of construction. Mr. Wills (loc. cit.) describes how
the animal deposits its completed pellet. He says that it is ejected between the body
and the tube, and then caught by the lower margin of the corona. Here it is retained
for a few seconds, as if the creature wished to make sure of a proper hold, and it is then,
by a sudden retracting of the body, dabbed down on the margin of the tube. The
pellets are deposited at irregular times, and the majority of them are so ejected as to
be whirled quite away by the coronal currents. Those that form the tube are laid in
transverse rings round the body so as to cut the ring obliquely (fig. 2d). The tubes are
generally neat, gradually widening to the top, but I have met with some in which the
pellets seemed to have been deposited in a most irregular fashion (fig. 2a). These
tubes, however, had probably suffered from some accident. The eyes are visible in the
half-grown animal.

Length. Scotch specimens up to 4, inch. Habitat. Sandhurst, Berks (Collins) ;
Sutton Park, Birmingham (A. W. Wills); Snaresbrook, the tube of unusually large
pellets (P.H.G.): marsh-pools, Fife and Perth (J.H.): not common.

' Mr. Cubitt’s and Dr. Collins’s drawings make the corona so like that of a Limnias that I am by
no means sure that they are deseribing (cistes pilula.

MELICERTADA.

iv
oe

di, BRACHIATUS, Hudson, sp. nov.
(Pl. IX. fig. 2.)

[SP. CH. Corona distinctly two-lobed; ventral antenne as long as the transverse
diameter of the corona, mobile, non-retractile; tube gelatinous, quite transparent, but
for adhering matters, subcylindrical.

The front in retraction is rounded, ending in two geminate hooked points. The
ventral antenne rise from swollen bases wide apart, and diverge on each side nearly in
the line of the body. They move independently of each other, often quickly, but not
spasmodically. In each can be seen a globose corpuscle within the tip, bearing one
seta, whence a double line (probably a tube or a nerve-cord of sensation) can be traced
throughout. A mastax of normal form, a long csophagus, an ample stomach, and a
distinct intestine, are plain; from this last a long up-turned rectum leads to the cloaca,
at half body-length. Laid eggs, of very long-ovate form, are usually seen, from one to
four in number, in the middle part of the tube.

Below the viscera the body suddenly becomes hyaline, and gradually tapers to a
slender foot, twice as long as the body, through which run many pairs of muscle-
threads. At the bottom, already much attenuated, it abruptly contracts to an exces-
sively fine thread, which adheres by a sucking disk to the base, ‘The investing tube is
wide and high, but is absolutely invisible; and can be inferred only from a crowd of
minute diatoms (almost wholly of one slender kind) that are entangled in its substance.
The cavity of the tube can be easily traced, of equal width throughout, a width deter-
mined by that of the body, which, however, rarely retracts sufficiently to enter it. The
foot generally displays few transverse wrinkles.

It is not reluctant to display its discal beauties. The corona is that of a Limnias,
composed clearly of two circles united; the dorsal gap wider than the ventral. Hach
half is conspicuously marked with a thick rib (muscle or vessel?) originating in the
common centre, and divaricating, with many branches, nearly to the circumference,
But, just within the margin, a concentric band connects these branches, forming a sub-
marginal edge, thick and dark, which is constantly thrown into varying puckers by
contraction ; the whole contributing greatly to the beauty of the corona.

This species, which is among the finest of Rotifera, was discovered in 1882 by Mr.
John Hood of Dundee, to whose successful researches this work bears grateful witness.
He obtained it from several lochs around; and sent a specimen (which did not survive
the journey) to Dr. Hudson, with many notes and sketches. Recently he has favoured
me with many specimens, which have freely increased in captivity with me, even in
very small phials, so as to be swarming, by scores, for months after their transmission.
Thus I have had abundant facilities for study and delineation of the species. It has
always occurred attached to filamentous weeds much crowded with impalpable ale.

Length, ;', inch to 3, inch. Habitat. Weeds in Scottish lochs (J.H., P.H.G.):
not rare.—P.H.G.]

di. (?) vELATUS, Gosse.
(Pl. D. fig. 8.)

Megalotrocha velata ’ ; : Gosse, Ann. Nat. Hist. 2 Ser. vol. viil. 1851, p. 198.
Melicerta ptygura (?) » Popular Sci. Rev, vol. i. 1862, p. 490, pl. xxvi. fig. d.

(SP. CH. Corona very large, circular, crossed by thick diverging ribs; teeth four
in each ramus; eyes two, cervical, permanent; tube habitually wanting.
This very beautiful form is aberrant, if indeed it is an Cicistes. My attempts to
assign it, first to Megalotrocha and then to Ptygura, must both be given up. The
H 2

84 THE ROTIFERA.

absence of frontal hooks, and the high position of the cloaca, forbid the latter identification.
The form of the trophi; the very distinct, small, three-sided intestine (a mark by which
the species may usually be identified at a glance), and the absence of any tube-proper,
make its position in (@cistes doubtful. Dr. Collins, indeed, who has met with it often,
and has sketched it in his Note Book, speaks of its occasionally throwing off irregular
mucus; but this seems scarcely a tube. I have lately had many specimens, and have
never seen an approach to a tube. The presence of two eyes, small but conspicuous,
and apparently permanent, is noteworthy. They are situated in the neck, moderately
wide apart. Dr. Collins, in one example, figures and describes them as rather close
together and near the edge of the corona, which is unaccountable.

The corona is a hyaline disk, of beautiful rotundity and of great size, being twice as
wide as the body when well expanded ;—shallowly funnel-shaped, but sometimes taking
the form of a lovely glass salver, with slightly raised edge, around which the great ciliary
waves play nobly. Turbid matters are sometimes poured off through the minute dorsal
notch. ;

The rectum may easily be traced, upward from the bottom of the intestine, to the
cloaca far above its summit. I have seen an egg, and also feces, discharged, after
which the cloaca protrudes lip-like (8d). Around the outside of the corona, investing
it to some height, is sometimes seen what seems a vascular tissue of granular yellowish
hue (8b), apparently movable, whence the specific name. A very good view of the
mastax enabled me to see that each hemispheric ramus is crossed by four teeth, nearly
parallel, whose points project beyond the edge (8e, 8/).

I found this fine species near London in 1849, in two examples; but never saw it
again for many years. Within a few months, however, Mr. Hood has sent me water
from a pond near Dundee, very rich in forms of Rhizota, among which many specimens
of GZ. velatus occur. I am tempted to give my ardent correspondent’s experience in
the procuring of these. It was in the very height of the great snow of early March,
in the present year 1886. ‘‘I went to the pond to-day to search for velatus—a difficult
and hazardous task. The pond is more than twelve feet deep, covered with thick ice and
snow. AsIlmew the exact spot . . . I cleared away the snow, and bored a number of
small holes in a circle of eighteen inches in diameter; then thrust down the central
plate, which gave me a large hole. I put down my line with sinker and grapnel, but
fished a long time with no result. At last a bit of the Myriophyllum came up, to which
I hope you will find specimens attached ;”’—as, I am happy to add, I did.

Length, ;},, to }; inch. Habitat. The Black Sea, Wandsworth (P.H.G.); Sand-
hurst (Dr. Collins); Dundee (P.H.G.; J.H.): rare.—P.H.G.]

(. umBELLA, Hudson.
(Pl. VII. fig. 4.)

@Meistes umbella . 5 ‘ A Hudson, J. Roy. Micr. Soc. (1878), vol. ii. 1879, p. 1, pl. i.
Cicistes longipes 6 0 0 : Wills, Midland Naturalist, vol. i. 1878, p. 317, pl. v. figs. 1, 2.

SP. CH. Corona large, nearly circular, crossed with thick ribs ; ventral antenne
long ; tube loose, very irregular, clay-coloured.

Mr. F. Oxley sent me, in June 1878, several specimens of this large and handsome
species, which he had just discovered in a pond at Snaresbrook, on the leaves and in
the axils of a Sphagnum. Its corona is so strengthened by thick ribs as to look some-
what like an umbrella. Two of these ribs are very broad, and run across from the
ventral to the dorsal side, and when the corona is viewed sideways are seen to project
a little above its surface. There is also on either side a branched rib with a triangular
space within it like a gusset. When the Rotiferon closes its corona it brings the ribs
together, the thinner portions being olded up between them. The thus infolded corona

MELICERTAD®. 85

forms a rectangular bundle that is characteristic of the species. The foot is unusually
long and slender. Two red eyes are distinctly visible in the adult, just below the surface
of the corona.

Length, ,; inch. Habitat. Ponds at Snaresbrook, Essex (F. Oxley) ; and Sutton
Park, Birmingham (A. W. Wills); Woolston, Cheltenham (P.H.G.) ; marsh pools, Perth
and Fife (J.H.): rare.

dE. styais, Gosse, sp. nov.
(Pl. IX. fig. 3.)

SP. CH. Corona circular ; dorsal gap not perceptible ; ventral antenne: mere tuber-
cules. Of large dimensions.

{I found this fine species on September 18, 1885, among impalpable floccose vegeta-
tion sent me by Mr. Hood from the Black Loch, near Dundee; a habitat which has
suggested a fanciful appellation, and which it shares with its neighbour and rival
@. brachiatus. It equals that species in size, being about 4, inch in height when
expanded ; its beautiful clear corona, of exquisite rotundity, being +4, inch in diameter.

The corona is strengthened with thick divergent ribs, very visible when viewed
obliquely or nearly laterally; but, in a direct front view, these disappear, and the
hyaline disk looks like a circular plate of clear glass, marked by a few almost invisible
curves. There are no antenne proper; a pair of minute knobs marking their place.
But for this, it might be mistaken for G/. wmbella. I saw no trace of eyes. The body,
of the usual form, contracts to a long and slender foot; which, at its pedal extremity,
dilates into a minute cubical knob, which adheres to a little heap of floccose. A tube
of loose gelatinous matter, of brownish hue, surrounds the body, of such a thickness
that its diameter is about twice that of the corona. It is undefined to the eye, but
carries an agglomeration of extraneous matters entangled in its substance.—P.H.G. |

Length, , inch. Habitat. Black Loch, Dundee (P.H.G.): rare.

Genus LACINULARIA, Schweigger.

GEN. CH. Cluster fixed, of many individuals, with adhering gelatinous tubes ;
corona heart-shaped, oblique, with its longer axis placed dorso-ventrally, and a deep
ventral sinus ; dorsal gap in the ciliary wreath very minute ; trunk without opaque warts ;
dorsal and ventral antenne absent.'

L. sociatis, Ehrenberg.
(Pl. VIII. fig. 1.)

Lacinularia socialis ; : c Ehrenberg, Die Infus. 1838, p. 403, Taf. xliv. fig. 4.
Leydig, Sieb. wu. Koll. Zeits. Bd. iii. 1851, p. 452, Taf. xvii.
Huxley, Trans. Micr. Soc. vol. i. N.S. 1853, p. 1, pl. i.
pl. ii. figs. 20-25.
” % r - Pritchard, Infusoria, 1861, p. 671, pl. xxxvii. figs. 19-25,
Megalotrocha socialis E ‘ Gosse, Popular Sci. Rev. vol. i. 1862, p. 494.
Lacinularia socialis 0 0 c Cubitt, Mon. Micr. J. vol. viii. 1872, p. 9, pl. xxiii. figs. 3, 4.
Hudson, Mon. Micr. J. vol. xiii. 1875, p. 45, pl. xci. fig. 8.
Bartsch, Rot. Hungaria, 1877, p. 19, Tab. i. fig. 1.

This common and yery beautiful Rotiferon, the only known species of the genus, is found
adhering in clusters, like little balls of grey jelly, to the stems and leaflets of pond-weeds.

’ Possibly they may Le very minute setigerous pimples, which have escaped observation.

86 THE ROTIFERA.

The cluster is a lovely microscopic object for a low power with dark-field illumination,
and can be easily placed in a live-trough without injury ; so that during the hundred
and thirty years which have elapsed since its discovery, it has naturally attracted the
attention of many observers, and has been the subject of special essays by Professor
Huxley and Dr. Leydig. It has, im consequence, been very thoroughly examined,
and only a few points of its structure remain as yet doubtful. These, as might have been
expected, are in the vascular and nervous systems ; and these alone require notice, as the
rest of its internal organisation, as wellas the general plan of the corona, ciliary wreath,
chin and buccal funnel, follows very closely that of MW. ringens.

The Vascular System.—Professor Huxley describes the two lateral canals as arising
from a common origin upon the dorsal side of the intestine (rectum), but Dr. Leydig
says that the lateral canals start from a common branch opening into a contractile
vesicle, which discharges itself into the cloaca: it will be seen that a similar doubt exists
concerning the termination of the canals in Conochilus volvox, and further investigation
is, | think, wanted to make the matter clear.

The Nervous System.—Professor Huxley (loc. cit.) describes and figures a ciliated
cup beneath the chin, just as in IZ. ringens ; and below this cup, underneath the surface,
on the ventral side, a ‘‘ bi-lobed homogeneous mass resembling in appearance the ganglion
of Brachionus.” This organ he supposes to be the true nervous ganglion. Dr. Leydig,
on the other hand, points out two nucleated polar cells, giving off threads, just below
the mastax, and two similar ones at the junction of the foot and trunk. These four
are, in his opinion, the nerve centres of L. socialis. Now, each of these suppositions
is liable to the same objection, viz. that it places the nervous ganglion in a unique
position. All the known nervous ganglia in the Rotifera lie towards the dorsal surface,
and the great majority are near the mastax, and not far from the eyes; there are no
other examples of nervous ganglia on the ventral surface, or in the foot. Besides, in
the only one of the Melicertade (viz. Conochilus) in which there is an obvious nervous
ganglion, it hes in the normal position; and M. Joliet describes the nervous ganglion
of I. ringens as being above the mastax towards the dorsal surface. No antenne
have as yet been observed, and the eyes are visible only in the young.

The Male—I had the good fortune to discover and study the male in November
1874, and published (doc. cit.) an account of it, and several other males, soon afterwards.
Fig. le gives a side view of it. It has a conical head fringed with a wreath
of long cilia, a cylindrical soft trunk, and a short, pointed, ciliated foot. There are
strong longitudinal muscles for withdrawing the corona into the trunk, and several
transverse muscular bands in the integument. The nutritive system is wholly absent.
Two secreting foot glands are present, as well as the lateral canals and their vibratile
tags. I several times thought I caught sight of the edge of the contractile vesicle behind
the upper part of the sperm-sac. There is a large nervous ganglion sending threads to
a dorsal antenna and two red eyes. A large sperm-sac fills nearly the whole trunk, and
ends in a broad tubular, ciliated, and protusile penis.

Length. About 7; inch; diameter of large cluster, about 1 inch. Habitat. On
water-weeds : common.

Genus MEGALOTROCHA, Hhrenberg.

GEN. GH. Cluster fixed, of many individuals without tubes ; corona kidney-shaped,
oblique, with its shorter axis placed dorso-ventrally, and with a deep ventral sinus ;
dorsal gap in the ciliary wreath very minute; trunk with four opaque warts in a row
on the breast; dorsal and ventral antenne absent.!

' Possibly they may be very minute setigerous pimples, which have escaped observation.

MELICERTAD. 87

M. auBornavicans., Ehrenberg.
(Pl. VIII. fig. 2.)

Megalotrocha alboflavicans . F Ehrenberg, Die Infus. 1838, p. 397, Taf. xliv. fig. 3.

° Pritchard, Infusoria, 1861, p. 665, pl. xxxii. figs. 374-378.
Gosse, Popular Sci. Rev. vol. i, 1862, p. 491.
Weisse, L’ Acad. Imp. St. Pétersb. 7 Sér. t. iv. No. 8, 1862,

p- 7, with figs.

Lacinularia alboflavicans ° C Cubitt, Mon. Micr. J. vol. viii. 1872, p. 9, pl. xxiii. fig. 5.

This is a comparatively rare animal, though it has been known for upwards of a
century. Had it been common it would never have been supposed to be a Lacinularia
without a tube, for only those who have never seen it could make such a mistake. It
differs obviously from Z. socialis in its shape and habits, as well as in its being orna-
mented with a necklace of four white opaque knobs, ‘‘ like a row of pearls,” stretching
from shoulder to shoulder across the ventral surface. ‘These are so placed, that when
the animal furls its corona they border the edge of its then pear shaped body.

The cluster radiates in all directions from a small space on the stem or leaf of a plant,
and often consists of both adults and their young. Now and then a young brood will
swarm out, as in Conochilus volvoz; and, when swimming away, circling round each
other in search of a resting-place, may easily be mistaken for a young cluster of that
species. The ways of the animal are unlike those of L. socialis. It is a much more
timid creature, and does not expand so freely. When a cluster is undisturbed, first one
and then another will contract with a sudden twist, to expand in leisurely fashion at its
own pleasure ; but every now and then a panic seizes the whole cluster, and they all
rush together into a contracted mass, with a curious circular sweep, as if some violent
eddy had struck them.

The creature has a peculiar habit of swelling out at times the surface of the corona,
so that it is curved up above the ciliary wreath; but in other respects the two ciliary
wreaths, the chin, and the buccal funnel are similar in plan to those of LZ. socialis; and
so is the whole alimentary tract. The two vesicles, which some take to be salivary
glands, and others mere horny stays to the buccal funnel and mastax, are yellowish ;
and so are the trophi. The gastric glands are somewhat three-sided in outline when
seen ventrally. The lateral canals and their vibratile tags are obvious (figs. 2 to 2c),
but the contractile vesicle (if any) has not been seen; neither has it been determined
how the lateral canals end posteriorly. No nervous ganglion or antenna has as yet been
seen, and the two red eyes only in the egg and young.

[Mr. W. G. Cocks, of Dalston, has been very successful in keeping this and other
fine Rhizota in a tank. He has favoured me with many valuable observations on the
habits and development of this species ; and I am indebted to him for a supply of speci-
mens. I noticed that, in one case, when an egg was discharged in my sight, it separated
and fell down among the crowded feet of the cluster ; while, in another, it hung awhile to
the cloaca after exclusion. Presently a young one was swimming free, probably hatched
in the trough. It was colourless, very transparent ; and swam smoothly, evenly, and
swiftly, by the rotation of the cilia on its expanded corona. Then came shooting-by a
slender creature (Pl. D. fig. 9a), about =, inch long, with truncate, apparently ciliate,
front, tapering regularly to the hind extremity. In this, though full of a bright granu-
lation, I could not detect any viscera, nor other organs. I conjecture this was the new-
born male of the same ; as fig. 9 is probably a new-born female.—P.H.G.]

In Dr. Weisse’s figure (loc. cit.) of the female embryo leaving the egg, it will be noticed
that the four opaque warts on the trunk, as well as the eyes and mastax, are already
formed.

Length. About ;4, inch; diameter of large cluster, about } inch. Habitat. On
plants in gently running streams, Weybridge, Surrey (W. G. Cocks); Kent (Cubitt,
Badcock): rare.

88 THE ROTIFERA,

* Genus TROCHOSPHMRA, Semper.

GEN. CH. Solitary, free-swimming ; body a perfect sphere ; buceal orifice on the
spherical surface ; principal wreath dividing the sphere into two hemispheres, and pass-
ing above the buccal orifice; dorsal gap in the wreath at the pole opposite to buccal
orifice ; secondary wreath a fragment on the under edge of the buccal orifice ; ventral
antenne extremely minute ; tube absent.

T. HQUATORIALIS, Semper.
(Pl. D. fig. 11.)

Trochosphera equatorialis . 0 Semper, Sieb. u. Kill. Zeits. Bd. xxii. 1872, p. 311, Taf.
xxiv., translated in Mon. Micr. J. vol. xiv. 1875,
p. 237, pls. exx. to exxii.

Who can complain here that a rough wrinkled skin, complicated external form, and
huddled-up organs haye rendered his utmost efforts almost fruitless ? Here is a creature
whose outer shape and texture have alike reached the very acme of simplicity; the one
translucent as the clearest water, the other rounded into a perfect sphere: an
animal created as it were for the study of its internal structure; its organs all sym-
metrically spread apart in due array, just as if a skilful demonstrator had teased them
out with delicate needles ; no one overlapping another, and all deftly hung to the walls
of a hyaline globe which not only upholds them, but also displays them to the utmost
possible advantage; for it has a band of cilia girdling its entire circumference, and
rolling it through the water, so as to present it in every possible point of view.

Trochosphera has a perfectly transparent spherical body with a principal ciliary
wreath running round what may be called the equator, and marking the common
boundary of what Prof. Semper calls the ‘‘ oral” and ‘‘ab-oral’’ hemispheres. In the
former lie nearly all the organs of the body; for only one nerve-thread and portions
of a pair of muscular bands are to be found in the other. At one spot in the equa-
torial ring of cilia there is a break in the wreath, and at the opposite extremity of
the diameter passing through this spot is the buceal orifice, which has a very small
secondary wreath fringing its oral or lower side.

The various internal organs are so well displayed in Prof. Semper’s figure, that
only a few points require notice. The trophi, though of somewhat peculiar shape, are
malleo-ramate. The lateral canals end in the cloaca, not in the contractile vesicle ;
and this latter, according to Prof. Semper, discharges itself into the intestine. The
nervous system can be well made out. From the nervous ganglion (ng), which lies
close to the mastax (mz), five pairs of nerves pass respectively to the ciliary wreath,
buceal orifice, lateral antenne (a’), lateral canals (Jc), and eyes (e); while a single
nerve thread (7) passes to the probable dorsal antenna (a).

The male is unknown.

It is obvious that if the aboral hemisphere were pressed flat, and the oral lengthened
out into a cone, we should have, in the altered Tvochosphera, a Rotiferon somewhat re-
sembling one of the Melicertade. For it would have a buccal orifice laterally placed; a
principal ciliary wreath surrounding the body, with a gap in it on what would then be
the dorsal side ; a portion of a secondary wreath passing round the edge of the buccal
orifice ; trophi of a Melicertan type; two minute ventral antenne, and a single dorsal one.
On the other hand, the absence of an attached foot, and of a complete secondary wreath,
and the difference of habit, make it no easy matter to say where Trochosphera should be
placed ; on the whole, I think it should be put among the Melicertad@ near Megalotrocha
and Conochilus.

Length. Diameter of sphere, ,\; inch. Habitat. Ditches in the rice fields of
Zamboanga, in the Philippine Islands (Prof. Semper) : rare.

MELICERTAD#. 89

Genus CONOCHILUS, Ehrenberg.

GEN. CH. Cluster free-swimming, of several individuals, inhabiting coherent gela-
tinous tubes ; corona horse-shoe-shaped, transverse ; gap in the ciliary wreath ventral ;
buccal orifice on the corona, and towards its dorsal side; dorsal antenne absent ; !
ventral antenne obvious.

Take a clay model of an Weistes, and cut off the head by a transverse section through
the neck. Lift up the head, and reverse its position, placing the surface of the corona on
the decapitated trunk, so that the entrance to the buccal funnel may point towards the
centre of the dorsal surface. There will thus be obtained a rough representation of the
relative positions of the trunk, corona, and ciliary wreaths in Conochilus. Such a
violent alteration in the general plan of the Melicertade might almost seem to entitle
Conochilus to a family by itself, but its affinities are so clearly with this group that it
may well remain here.

On the surface of the corona,? close within its edge, and parallel to it, runs a groove,
which is broadest and deepest opposite to the dorsal surface, where it is confluent with
the entrance to the buccal funnel. The groove grows both narrower and shallower on
each side as it approaches the ventral surface, and ceases just before reaching a ventral
gap in the corona.

The buccal funnel, except at its wide entrance, is covered by a sloping roof, formed
of the uplifted corona, which here rises into a kind of pent-house, notched at its apex.
The principal wreath runs round the outer edge of the groove, and is joined, at each side
of the ventral gap, by the secondary wreath. This latter fringes the groove’s inner
edge ; and on reaching the buceal funnel, bends sharply back, rising up each edge of its
walls, till it has reached the notch described above; so that in Conochilus, as in other
Melicertade, the entrance to the buccal orifice lies between the two wreaths, and is bor-
dered by the secondary one.

The two known species differ considerably in their modes of clustering, and in their
antenne : they apparently closely resemble each other in other points, but only one
has been really studied, viz. C. volvow.®

C. votvox, Hhrenberg.
(Pl. VIII. fig. 3.)

Conochilus volvox . 5 6 Ehrenberg, Die Infus. 1838, p. 393, Taf. xliii. fig. 8.

Eichwald, Dritt. Nacht. z. Infus. Russlands, 1852, p. 520.

5 5 Cohn, Sieb. u. Koll. Zeits. Bd. xii. 1863, p. 197, with figs.
9 9 ° 5 0 : Pritchard, Infusoria, 1861, p. 664, pl. xxv. 365-370.

Megalotrocha volvox 3 0 > Gosse, Popular Sci. Rev. vol. i. 1862, p. 491, pl. xxvi. figs.e,f.

Conochilus volvox . : F Davis, Mon. Micr. J. vol. xvi. 1876, p. 1, pl. exliii.

Bedwell, J. Roy. Micr. Soc. vol. i. 1878, p. 176, pl. xi.

. p 5 C Hudson, J. Roy. Micr. Soc. vol. ii. 1879, p. 3, pl. ii.

a 5 4 ° 5 Inhof, Zool. Anz. No. 147, 1883.

1 Possibly very minute.

? Ehrenberg misunderstood the corona of C. volvox, and described it as surrounded with a single
wreath of cilia and bearing four papille on its strface. He placed the buccal orifice on the ventral
side, where the ventral gap is; and suggested that the four papillw might be a sort of upper lip to the
mouth, the edge of the disk itself being the lower one. Dr. Cohn, in his otherwise admirable paper
(loc. cit.), draws the buccal orifice on the ventral side, and wrongly places the antenne between it and
the dorsal surface. His conical protuberance over the antenne is also singularly out of shape and
proportion. The corona and antennx were first correctly described by Mr. Davis (loc. cit.), whose
observations I haye repeatedly verified.

% Strophosphera ismailoviensis (Poggenpohl, N. Mém. Mosc. t. x. 1876) is, I think, a Conochilus ;
with two short separate antenne lying between a pair of ventral hooks.

90 THE ROTIFERA.

SP. CH. Cluster spherical, consisting of many adults and their young; tubes so
compressed together as to be indistingwishable from each other ; ventral antenne on the
corona, between the buccal orifice and the ventral gap, adnate at the base.

No microscopic object is more beautiful than this lovely globe of living creatures,
each bearing its flashing crown of cilia, its ruby eyes and orange-tinted jaws. Fortu-
nately it is as common as it is beautiful, and is equally at home in the Swiss Lakes,
in the Scotch Lochs, and in the pools of Hampstead Heath.

The animals all radiate from a common centre (fig. 8e), the extremities of their
feet being close together, though not in actual contact. The action of their ciliary
wreaths imparts a slow motion to the globe, which rolls along, rising and falling, and
often returning on its course, In a very aimless fashion. The globe is formed by the co-
operation of its inmates, each contributing its secretion to the structure. The newly-
hatched free-swimming young may be seen circling round each other, with their bodies
curved, and the extremities of their feet directed towards a central spot in the group.
In this way they will swim off in a swarm, not actually cohering, but keeping all close
together. Ihave not been able to follow the process further ; but, no doubt, all soon
begin to form some sort of tube, and their united secretions fix the swarm together,
and at last combine them into a small globe, to which fresh additions are constantly
made. A young globe increases its size also, not only by the growth of the original
company, but by the addition to it of its newly-hatched young; which, as they emerge
from the egg, squeeze a place for themselves among their elders.

But the process has its limits. After a time the globe is too thickly packed, and a
young swarm starts off as already described. The largest globes often separate into two
portions, each of which soon rounds itself into a sphere ; no doubt they are torn apart by
the strain on them produced by the opposing action of the ciliary wreaths in opposite
hemispheres.

The internal structure resembles that of Melicerta, but a few points require notice.
The trophi! are tinted orange-red, and so ig the lower end of the buccal funnel, where
are the lips which form an entrance to the mastax: these latter resist the action of
caustic potash. The stomach appears to be divided into two chambers, which lie sym-
metrically on the right and left sides of the body ; while between and below them the
intestine is curved abruptly back towards the dorsal surface; so that its long rectum
ends in an unusually highly placed cloaca.? Indeed the whole of the viscera are, as it
were, tucked high up into the trunk, leaving its lower end empty of all but the longi-
tudinal muscles. Six of these run from the head over the trunk, down the broad, trans-
parent, spindle-shaped foot. Five or six bands of transverse muscles cross the trunk,
at somewhat regular intervals, from the neck to where it joins the foot. This latter is
generally drawn up a little into the body, at its junction with it, so as to make there a
conspicuous fold in the integument. The vascular system has no contractile vesicle,*
but its function is performed by the cloaca; which I have often watched dilating and
emptying at regular intervals. The lateral canals arise in a plexus on each side of the
corona, slope downwards dorsally to a similar plexus in each shoulder, and throw out
on their way branches, above and below the nervous ganglion, which appear to run into
each other. From each shoulder-plexus the canal is continued, still near the dorsal

1 Judge Bedwell (Joc. cit.) gives a minute, careful, and original account of the structure and action
of the trophi.

2 Mr. Gosse (loc. cit.) deseribed and figured the fecal pellets, which he supposed to be eggs. His
account of them is as follows :—‘ Their form is very peculiar ; it appears to be nearly circular, flattened
on one side and conyex on the other; there is considerable difference in their size; they are of a
pale-yellow hue, marked with several blackish specks.”

3 Dr. Cohn (loc. cit.) says that each lateral canal ends in a dilated portion or small contractile
bladder, which empties itself into the cloaca, and that the two act alternately. The arrangement,
however, seemed to me to be that given in the text. I have drawn in Pl. VIII. fig. 3i what I saw. The
figure shows a lateral canal (Jc) ending in what I supposed to be the cloaca (cl), and which dilated and
contracted regularly. Unfortunately, I have not been able to procure a specimen of C. volvox since I
read Dr. Cohn’s paper.

MELICERTADAS. 91

surface, down to the cloaca. The vibratile tags can be easily seen. There is a con-
spicuous nervous ganglion on the dorsal side, just above the neck, and below the two
eyes. These latter are beautiful little hyaline spheres (fig. 8h) resting on patches of
crimson pigment.!_ The two antenne rise from the corona, on the sloping walls of the
buccal funnel between it and the ventral gap (fig. 8a, a). They are adnate at the base,
and each carries a bristle that ean be withdrawn within a tubular sheath (fig. 39), as in
Melicerta. The ovaryis frequently obscured by a large egg, lying across the body, in which
the red eyes, moying cilia, and mastax of the young animal are distinetly visible. I have
frequently noticed living spermatozoa attached to the outside of the ovary : how they can
get there it is not easy to see, unless they can find their way from the cloaca, up the
lateral canals, and out of the vibratile tags into the body-cavity.

I have watched the formation of an ephippial egg from the first enclosing of a con-
siderable portion of the ovary, through the changes shown in figs. 8k, 31, 8m, to the
ultimate production of an egg (fig. 31), covered with a deep layer of hexagonal cells,
and bristling with spines, from each spot where the angles of the hexagons meet. As
Mr. Davis has well observed, it is a misnomer to call these *‘ winter ” eggs, for they oceur
in all seasons of the year.

The male (Pl. VIII. 3d and 3p), as usual, consists of little else than a sperm-sac and
penis. Its general appearance when swimming is shown by Mr. Davis (Joc. cit.) and its
internal structure has been worked out by Dr. Cohn, one of whose figures is reproduced
in Pl. D. fig. 10. Dr. Cohn (Joe. cit.) says that the nutritive system, from mouth to
cloaca, is wholly wanting ; that the vascular system is indistinct, though probably pre-
sent ; that the whole head is occupied by a great nervous ganglion ; and that there are
two eyes, which consist of refracting lenses set in pigment. He also describes, and
figures, the spermatozoa (Pl. VIII. fig. 3¢), which he saw under unusually favourable
circumstances ; and noticed their attachment to the outside of an ovum (fig. 87).”

Length. Diameter of large cluster, about 5}, inch ; length of individual, about ;4, inch.
Mr. Gosse has counted as many as 70, and Mr. Davis 100, in a single cluster. Habitat.
Lakes, clear ponds, and pools: common,

0. possuarius, Hudson, sp. nov.
Pl. VIII. fig. 4.
Conoco ehriles ( V 8 )
Cepkalosiphen dossuartus . . Hudson, J. Roy. Micr. Soc. 2 Ser. vol. y. 1885, p, 611, pl. xii. fig. 4.

SP. CH. Cluster wnsymmetrical, of one adult and a few of its young ; tubes dis-
tinct ; ventral antenne below the corona, long, adnate for nearly their whole length.

This rare species was discovered by Mr. Bolton in September 1884 near Birmingham.
It isremarkable for the size, shape, and position of the antenne, which stand on the arched
ventral surface like a rifle-sight on the barrel. The specimens that Mr. Bolton sent me
were all solitary, carrying with them, as they swam, their cases with the contained eggs;
but Mr. Bolton tells me that the clusters which he usually met with consisted of one
adult and a few young individuals of various sizes. On one occasion, too, he saw an
adult with one large egg, and four much smaller eggs in its tube. If these latter were
male eggs, and the former a female one, this observation would, I believe, be unique.

I had no opportunity of studying the internal structure of this Rotiferon closely ;
but I detected no difference in this respect between this species and C. volvoz.

Length. My solitary specimen was ;!; inch. Habitat. Near Birmingham (T.B.).

Dr. Imhoff says (Joc. cit.) that in the specimens in Lake Zug the pigment is black, and Dr. vy.
Eichwald (/oc. cit.) found specimens, in ditch-water at Hapsal, in which the eyes were invisible.

? The Rey. Lord 8. G. Osborne has described (in a letter to the ‘English Mechanic,’ March 1, 1878),
clusters of Conochilus volvor which bear at their centres bundles of fine stick-like diatoms. I am
indebted to his Lordship for a cluster, mounted by himself, and containing these needle-shaped bodies.
They appear to be of three kinds; they are colourless, and their distinctive markings (if any) are so
obscured by the rotiferous jelly, that it is very difficult to say whether they are diatoms or desmids.
Lord Osborne’s explanation of their presence in the cluster is no doubt the true one: namely, that
they are drawn in point-downwards, bit-by-bit, at each sharp contraction of Conochilus into its ball.

CEP AE irre, Welt

PAR rns rn

BDELLOIDA.

Si que de animalculis infusoriis dici possunt enarrentur, verbaque et
oculorum acies sufficerent, dicendi nullus finis esset. Paucissima mag-
nificentie et splendoris Numinis optimi maximi documenta prodere mens
humana valet ; in plurimis stupet et obmutescit.—O. F. MULier.

He, who feels contempt
For any living thing, hath faculties
Which he has never used;
. « » thought with him
Ts in its infancy.
Worpsworta.

CHAPTER VII.

Order II. BDELLOIDA.

Swimming ' with their ciliary wreath, and creeping like a leech; foot wholly retractile
within the body, telescopic, ending almost invariably in three toes.”

The Leech-like Creepers form so natural a group of animals that all the classifiers of
the Rotifera have placed them by themselves. Ehrenberg, Dr. S. Bartsch, Herr
K. Eckstein, have arranged them in the family Philodinga; Dujardin, in the order of
the Rotiféres ; and Dr. Leydig, in his un-named second family of Rotifera ‘‘ with a
long, jointed, telescopic, retractile foot.” This extremely characteristic foot is to be
found only in the two families of this order, the Philodinade and Adinetade. The
longitudinal muscles, which pass down the foot, end at intervals below each other, so
that their contraction draws the lowest part of the foot into that just above it, and this
in its turn is drawn into the part above, and so on; until the whole foot can be shut up
like a telescope, and withdrawn completely into the trunk.

A special interest attaches to the BDELLIOIDA. Specimens of various species in
both the families have been dried, suffered to lie in that condition for three or four years,
and then brought to active life again by being placed in water. I have no space to
give the history of this question, and of the controversies that have arisen about it,
some of which, indeed, are still as lively as ever; I shall therefore confine myself simply
to a relation of facts whose reality may be easily tested, and of the satisfactory explana-
tion of them given by Mr. Davis.4 If specimens of Philodina roseola be placed with a
little clear water on a slip of clean glass, and the water be quickly dried up, they will
all be killed; no watering will revive them. I have tried this scores of times and never
met with a case of recovery. But if the rotifers be placed in a cell that contains a
little sand, or moss, then the cell may be dried even in vacuo over sulphuric acid; and
yet, when water is again added to it, in the majority of cases, some of the Rotifera will
be found to be still alive: or the cell with the water, sand &c., and the animals may be
gradually heated up to 200° Fahr., and yet some of the creatures will probably recover
if, when the cell is cool, fresh water be added: or once more, the cell may be laid aside
for several years in utter dustiness, and still, on the addition of a few drops of water, the
chances are that, in the course of an hour, a few of the animals will revive. Now the
real point is obviously this. Ifa Philodine can be revivified after haying been dried in

1 (The swimming faculty in this order is very subordinate. We never see a Philodina or a Rotifer
sailing smoothly hither and thither, turning waywardly on its course, and roving about with no
apparent aim, like a Microcodon or a Euchlanis. It will bore through a mass of vegetation, and, on
coming to its margin, shoot straight away on a voyage of discovery. But the very first new bit of
sediment that it meets arrests it; it instantly creeps into this, and makes this its home for a while :
as if its natatory powers were used merely for change of place, as distinguished from actual enjoyment
in swimming.—P.H.G.]

? All the known British species have three toes. Dr. L. K. Schmarda has described some foreign
species with only two toes; but I think it probable that he is mistaken.

3 Mr. Jabez Hogg (English Mechanic, Jan. 16, 1885) says that he has seen rotifers revive “after
fifteen years’ careful seclusion.”’

* Mon. Micr. J. vol. ix. 1873, p. 206.

96 THE ROTIFERA.

sand over sulphuric acid, or gradually heated to 200° Fahr., or left to the neglected dust
of years, why will it not recover from the effects of quick evaporation, without sand, on
a glass slip, in the comparatively moist air of a sitting-room? It has been suggested
that, by burying itself in the sand, the animal obtains a covering to protect its internal
fluids. But this explanation does not meet the case of Rotifera heated in sand up to
200° Fahr. Surely hot sand at this temperature would be a poor protection for the
natural juices of a soft-bodied Rotiferon. On taking some earth or sand containing
dried-up Philodines, we shall see them dotted here and there, adhering to the earth’s
particles, and looking like little red, orange, or white balls. If one of them be picked
out, and a drop of water placed on it, after a quarter of an hour or so, a part of the
infolded foot will usually shoot out with a jerk, and the foot itself will then gradually
lengthen joint by jot. Often, at this stage, the jaws will be seen to be at work, and
the head will be driven out with its corona and wreaths still furled: at last these in
their turn open, and the recovered animal begins to roam about, or to work for food.
Now if, before we moisten the rotiferous earth, a bright light be thrown down on the
ball-like Rotifera, it will be seen that each globe has a nearly smooth glittering surface,
as if it were coated with a gelatine that filled up the hollows between the stout ridges
which run from head to foot. This is the key to the puzzle; for Mr. Davis suggests
that the Philodine survives the air pump, oven, and sun-baked gutter, by drawing-in its
head and foot into a ball, and then secreting round itself a gelatinous coating which
hardens in air and effectually preserves its internal fluids from evaporation. That the
gelatinous coat does preserve these fluids Mr. Davis proved by crushing the little balls
and finding them all moist within.

But why can the creature do this when sand or moss is present, but fail to do it
under much less severe trials in their absence? Here, too, Mr. Davis’s explanation is
complete. The water dries more slowly when there is sand or moss in it.! The Philo-
dines (who are gutter-lovers) are trained in being dried up under these conditions.
They naturally creep to the little heaps of sand &c., where the water lingers longest,
and, finding it going, contract themselves into a ball, pour out a viscid secretion over
their bodies, and prepare for the worst. But all this takes time, and, on the clean glass
slip, not only does the water evaporate too quickly, but the animal is too restless in the
unusual conditions in which it finds itself to attempt its ordinary defence. As I have
often seen, they roam about, vainly seeking shelter, till it is too late; they are overtaken
by the rapidity of the evaporation, and dry up never to recover.

1 It has been questioned whether the presence of sand in a cell, or in a gutter, does retard the
evaporation of the water. An experiment or two would soon satisfy a doubter; and a little considera-
tion will show the cause of the retardation. When a drop of water is enclosed by three or four morsels
of silex, nearly in contact, it is protected by the silex from evaporation everywhere except at the
surface. In fact it is in a similar condition to water in an uncorked bottle. Of course the water will
dry up in such a bottle at last, but it will evaporate very much more slowly than it would do were it
poured out on a marble slab.

If Philodines be left in a zoophyte trough, they will often be found dried up in one of its corners,
for the water lingers longest in the angle formed by the bottom and sides. Their instinct leads them
too, when other defences fail, to gather together in clusters so as to protect the evaporating water by
their own nearly-touching bodies. The Rev. E. J. Holloway, taking advantage of this habit, has suc-
ceeded in drying up groups of P. roseola, on slips of clean paper, quite free from sand or rubbish
of any kind. He kindly sent me two or three of these slips; and an inspection of them under the
microscope confirmed the correctness of Mr. Davis’s theory. The fibres of the paper had evi-
dently delayed the evaporation long enough to enable the rotifers to resort to their customary
defence. Each Philodine is the centre of a patch of glutinous secretion, which meets the similar
patches, surrounding its neighbours, in a succession of straight lines; so that the whole group has
quite a tesselated appearance. Here and there, where fibres pass over or through a group, long tongues
of the secretion stretch from the animals to the fibres; and, in one case, a rotifer, that had tried to
squeeze itself under some interlacing fibres, had been caught; and, so held, had been moored to half-a-
dozen others by radiating viscous cords. The efficiency of the protection was at once shown by dipping
one of the slips into water, and watching the Philodines revive as the secretion dissolved.

PHILODINADZ. 97

All the Rotifera seem to possess the power of secreting a viscous fluid, which they
put to various uses. The Rhizota form their cases of it; the Ploima and Scirtopoda
draw it out in long threads from spots to which they have adhered, and thus moor them-
selves to external bodies; while the Bdelloida, by coating themselves all over with it,
not only resist the extremities of heat and drought, but set at defiance Old Time him-
self,

Family III. PHILODINADA.

Corona a pair of circular lobes transversely placed ; ciliary wreath a marginal con-
tinuous curve, bent on itself at the dorsal surface so as to encircle the corona twice, with
the buccal orifice between its wpper and lower curves, and having also two gaps, the one
dorsal between its points of flecwre, and the other ventral in the upper curve opposite to
the buccal orifice ; trophi ramate.

The genera of this family resemble each other so closely that it has often been
suggested that they should be reduced to one. They differ from each other chiefly in
the number and position of their eyes. One genus has them at the free end of the
cylindrical frontal column which forms the anterior portion of the head; and within
which, through a fold on its ventral side, the rotatory apparatus can be withdrawn. In
another genus they are placed within the neck; while in a third they are entirely
wanting. Now, strong objections have been made, by Dujardin and others, to Ehrenberg’s
use of coloured spots for the purposes of classification; mainly on the ground that it is
not certain that they are really organs of sight: and it is true that, in many cases, there
is little else to be seen in these so-called eyes but an irregular spot of pigment. On the
other hand, some of the Rotifera have unmistakable eyes, consisting of a spherical lens
seated on a sort of red, black, or purple cushion. Nerve-threads too, in some species,
can be traced from the ganglion to the eyes; and by this means the general positions
and appearance of coloured spots, that really are eyes, have been established. Moreover
(as might have been expected), the undoubted eyes prove to be in these cases good
generic characters. When, therefore, pigment spots are visible in positions that the
undoubted eyes usually hold, it is reasonable to consider them to be organs of vision
however humble, and to make use of them with other characters in classification. In
the genus Rotifer, nerve-threads may be seen passing from the ganglion to the eyes
in the frontal column; and in Rotifer vulgaris Dr. Otto Zacharias has observed ‘ that
each of the two carmine-red eye-spots is furnished with a crystalline body.’’ Again, in
the genus Philodina the position of the red spots with respect to the nervous ganglion is
precisely that which is held by such unmistakeable eyes as those of Conochilus volvo.
I have decided, therefore, to retain the old genera with only a few alterations.

Genus PHILODINA, Ehrenberg.

GEN. CH. Eyes two, cervical.

The Rotifera comprised in the genus Philodina, though technically separated from
the rest of the family by their having two eyes in the neck, can be generally recognized
at a glance by their greater stoutness of build, by their larger heads, by their more
powerful wreaths, and by their habit of so contracting the foot as to form an abrupt
division from the trunk. The corona and ciliary wreath would closely resemble those of
Limnias, were it not for the break in the latter just opposite to the buccal orifice, by
which the upper wreath is converted into two segments of circles. The animal, too,
holds itself differently from the Riizota while it is feeding; for it slightly arches the
dorsal surface so as to throw forward its dorsal antenna; while the Rhizota (with the
exception of Cephalosiphon) reverse this, and arch the ventral surface so as to throw
forward the two ventral antenne. A Philodina or Rotifer, when creeping, shows no

I

98 THE ROTIFERA.

external sign of corona: the animal tapers to a point in front as well as in rear. It attaches
itself by the tip of its head, and then, releasing and shortening its telescopic foot, takes
a fresh hold and arches its body like a leech or geometric caterpillar : it then releases the
head in its turn, extends its body, and takes hold again. When it wishes to swim, or to
feed, the front of the head is arched backwards ; and, by the action of the transverse
muscles diminishing the visceral cavity and so driving forward the body fluids, the
infolded corona is forced out of a puckered slit on the ventral surface, just where the
head joins the trunk. As the corona is pushed out, each disk begins to unfold, and its
cilia to act; while at the same time the tapering forepart of the head, or column, is thrown
backward, falling on the neck, between the lobes of the corona, much as the hood of a cloak
falls wpon a lady’s shoulders, when it has been dropped from her head. The trunk is fre-
quently marked with longitudinal furrows, which make it difficult to observe the viscera ;
and in some species it is tinged with reddish yellow, or brown; while the extremities are
usually free from colour. The penultimate joint of the telescopic foot, in every species
but one, carries a pair of soft tapering processes, called spurs, which appear to be useful
in giving the Rotiferon a firm hold. The method of attaching itself is this: the three
soft toes, rendered sticky by a secretion that exudes from them, are first fastened to the
object; then by the contraction of the longitudinal muscles the last joint is drawn over
the toes, and the penultimate joint over the last; till the penultimate touches all round
the object to which the animal is attached, and the spurs also are brought into contact
with it. By this means the Philodine is securely fastened so as to be able to resist the
action of its ciliary wreaths, or to dart back without letting go.

There are a few points in the internal structure that call for notice. The mastax
contains two stout rami, whose appearance is best described by Pl. C. III. fig. t7. They
are crossed by two or three principal teeth, with sharp points projecting beyond the
internal ridges of the rami, and by a multitude of minute ridges parallel to the teeth.
There are also faint indications of the three chitinous loops, attached to each ramus,
which are conspicuous in the malleo-ramate type.

The stomach, intestine and rectum (unlike those of Rhizota) are nearly in a straight
line, and the cloaca is situated below the junction of the foot and trunk. ‘The walls of
the stomach are unusually thick and absorbent; and become tinged with coloured food
almost immediately after it is eaten. The stomach, when empty, is reduced to a tube of
narrow bore, whose end dilates into a globular intestine ; there appears to be a sphincter
muscle separating the two.

Gastric glands, though small in size, are usually visible; and foot glands con-
stantly.

The contractile vesicle can be readily seen symmetrically placed in front of the
intestine, and though it is difficult to make out the lateral canals, it is generally easy to
see some of the vibratile tags. A large triangular nervous ganglion lies in the neck, its
apex pointing forward, and with a red eye on either side of the apex. The dorsal
antenna! is long, tubular, and setigerous ; its terminal part can be withdrawn within the
basal, in the same telescopic fashion as that i which the foot is shortened. No ventral
antenne have been recorded.

The reproductive system has been but imperfectly made out. The ovary, with its
contained germs, is distinctly visible on either side of the stomach, but no oviduct has
as yet been detected.

When a germ becomes developed into an ovum, it is seen, as it grows, to be gradually
separated by a constriction from the rest of the ovary, and at last appears to drop off
into the body-cavity, in which the young is sometimes completely hatched.

Both the living young and the egg have been seen to issue from the cloaca, but it

1 (The occipital antenna is normally three-jointed, but in some species the third joint is habitually
concealed, in others protruded. Yet this, though characteristic, is not invariable. The terminal joint
is three-lobed, each lobe carrying a projecting seta.—P. H. G.]}

PHILODINAD®. 99

is difficult to suggest how this is managed, as there appears to be no communication
between the body-cavity and the cloaca.!
No male has as yet been observed among any of the Philodinade.

P, ERYTHROPHTHALMA, Ehrenberg.

Philodina erythrophthalma . r Ehrenberg, Die Infus. 1838, p. 499, Taf. Ixi. fig. 4.
fr 7 . . Pritchard, Infusoria, 1861, p. 705, pl. xxxviii. fig. 4.

(SP. CH. Body smooth with a thick bulging collar; corona ample with a broad
shallow sulcus ; frontal column having no proboscis ; antenna decwrved, three-jointed ;
eyes conspicuous rond-ovate; teeth two ; foot stowt gradual. Animal hyaline, colourless.

The characters assigned to this and the following species must not, I confess, be
pressed with minute exactitude; nor are they all of equal value. Some of the species
do not differ very obviously inter se. Still, I think, all are specifically distinct ; and the
cumulate character, which, with some thought and care, I have assigned to each, may
aid the scient in discriminating forms too easily confounded.

This first species of the genus is one of the most difficult to be diagnosed with pre-
cision ; though it is of conspicuous size, and of so common occurrence as to fall very
early under the notice of the student. It was almost the first of the Rotifera ? which
I essayed to describe and delineate, nearly seven-and-thirty years ago, from specimens
obtained in the north suburbs of London.

The most readily observable feature is, that below the corona, itself of ample dimen-
sions, there is a thick prominent neck, bounded by sensible constrictions, Thus it seems
inseparable from Professor Ehrenberg’s P. collaris ; and, indeed, I shrewdly suspect
these to be but one and the same species, in different stages of growth. The gradual,
instead of sudden, transition of the trunk into the stout foot, is another character easily
noticed. The proboscis, which in this family is general at the tip of the frontal column,
seems, here, wholly wanting ; the truncate tip having only a slight transverse depression.
But the point is peculiarly difficult of determination in this species.

The specific name, besides being repulsive from its uncouth aggregation of unpro-
nounceable consonants, is unsuitable, because undistinctive. The possession of red eyes
is common, not only to all Philodine, but almost to all Rotifera.

Length, ;3, inch to ;, inch. Habitat, weedy pools, widely distributed : common,—
PAEGa

P. rosroua, Ehrenberg.
(Pl. IX. fig. 4.)

Philodina roseola . ‘ ; . Ehrenberg, Die Infus. 1838, p. 499, Taf. Ixi. fig. 5.
y > : : 5 ; Pritchard, Infusoria, 1861, p. 705, pl. xxxv., fig. 490.

[SP. CH. Body smooth, with no constriction nor swelling at the neck; corona
moderate, with a deep square sulcus ; antenna two-jointed, nearly horizontal ; eyes small,
oblong, oblique; teeth two*; foot stout, gradual. Translucent, ruddy in hue.—
P.H.G.]

No doubt it was this common and hardy species which Leuwenhoek discovered in

' See footnote, p. 103, for a suggested explanation of the difficulty.

2 [It was the second. Huchlanis dilatata was the very first.—P.H.G.]

® Lord Osborne kindly sent me many beautiful specimens of the trophi of P. roseola, which he had
mounted both plain and tinted with carmine. They were in every possible position, so as to admit of
a thorough study of the jaws. Among these I found several with two teeth only in each ramus, and
a few with two in the one and three in the other. Iam aware that, when not accurately focussed, this
appearance will be sometimes improperly obtained; but I took care, by delicate focussing, to be able to
count the pointed ends of the teeth in each case. Dr. Oskar Schmidt has noticed the same thing in
Rotifer vulgaris (Archiv f. Naturgeschichte, xii. Jahrg., 1 Bd. 1846, p. 69, Taf. iii. fig. 4).—C. T. H.

12

100 THE ROTIFERA.

the form of little pink balls in the dried-up dirt of a house-gutter ; and whose revivifica-
tion he describes. It is very common in ponds, water-butts, and housetops ; and will
bear to be dried up and reanimated, again and again, without injury. It is, too, most
prolific in situations that suit it; and these are sometimes odd enough. Lord §. G.
Osborne, for instance, found that the dust of two stone vases in his grounds at Blandford
was thick with the little pmk spheres of P. roseola, and with the white ones of Adineta
vaga (Callidina vaga, Davis); and he supplied his microscopic friends for years with
this rotiferous dust.

[The body is sometimes of a delicate flesh tint, often deepening to full rich red in the
cellular walls of the ample stomach, but fainter at the head and foot; it is evident that
the tint does not depend on the nature of the Rotiferon’s food, and it is quite as glowing
in the half-grown animal.

The corona is larye, with a deeply cleft sinus, and the two wheels of the ciliary
wreath are remarkably fine. The frontal column is large, cylindrical, truncate, and
strongly ciliated. The proboscis has a soft decurved hook on its very front (fig. 4d),
which is probably a tactile organ of great sensibility. I believe that I have seen
it used for grasping the slender stems and filaments, laying hold of one between
the hook and the face. In progress through clear water the creature often makes a
perceptible snatch forward, as if it caught prey with the organ, though none was
visible. Only in accurate profile, and full extension can this be seen. The broad
head of the stomach embraces the base of the mastax ; and, when the animal is extended,
this viscus is so stretched that the middle portions are drawn thin, while the ends are
dilated. There is a short round distinct intestine; and the cloaca is at the base of the
first joint of the foot. Two earlike triangular gastric glands are visible, one on either
side of the mastax ; and there is a small contractile vesicle which contracts about every
thirteen seconds: but the colour of the body and its longitudinal folds interfere greatly
with the sight of the internal organs. The eyes are of a beautiful pale red; but are in-
visible by reflected light. Under pressure eight transverse muscles have been distinctly
seen, as shown in fig. 4d.—P.H.G.]

Length. When extended, about ;1,; in a dried condition they are globes of ;4, to
zoo Inch in diameter. Habitat. Ponds, water-butts, house-gutters : common.

P. crrrina, Ehrenberg.
(Pl. IX. fig 6.)

Philodina citrina . 6 3 < Ehrenberg, Die Infus. 1838, p. 501, Taf. Ixi. fig. 8.

Gosse, Tenby, 1856, p. 299, pl. xix.

Pritchard, Infusoria, 1861, p. 705.

Eckstein, Sieb. w. KOll. Zeits. Bd, xxxix. 1883, p. 353,
Taf. xxiv. fig. 14.

(SP. CH. Body smooth with a distinct constriction below the swelling disk, but no
collar; corona wide, with a deep square sulcus; antenna nearly horizontal; eyes
minute, oblong, oblique; teeth two ; foot moderately slender, abrupt. Transparent,
yellow.

There is great resemblance of form between this and the preceding ; but the differ-
ences enumerated above, though mostly minute, help to distinguish it. The colour,
however, is the main peculiarity. This is normally a rich clear yellow, like a topaz;
yet specimens occur in which the hue is much paler and duller: and the extremities are
always colourless. Under reflected light the creature is an object of great beauty. The
citron hue becomes positive, and brilliant, separated abruptly from the hyaline extrem-
ities ; while the whole animal assumes a sparkling, glittering appearance, reflecting the
rays of light from various points, as if it were carved out of a precious stone.

Though there is no turgid neck, as in P. erythrophthalma, there is a more marked
constriction than in P. roseola, the hemisphere which carries the corona being more

PHILODINADAL. 101

ventricose, and marked more distinctly with oblique ridges. The period of the con-
tractile vesicle is about sixteen seconds.

It is lively and sprightly. It breeds freely in captivity; in a phial it congregates at
the very margin of the water; if they are numerous, a glance along the water line with
a lens gives a pleasing sight ; it reveals a whole array of the tiny creatures hanging head-
downward, in the ridge of water produced by the attraction of cohesion,their amber-like
bodies of various sizes, and their broad white crown-wheels all in full play. They do
certainly appear to have the instinct of companionship, as Ehrenberg has observed of
another species. :

Length, ;1, inchto!,inch. Habitat. Widely scattered, but by no means common.
Near London; Widcombe Pond, Bath; Tenby (P.H.G.).—P.H.G.]

P. MEGALOTROCHA, Hiwenberg.
(Pl. IX. fig. 7.)
Philodina megalotrocha . 5 Ehrenberg, Die Infus. 1838, p. 501, Taf. Ixi. fig. 10.
3 0 0 5 Pritchard, Infusoria, 1861, p. 705.

[SP. CH. Body smooth, with no constriction nor swelling at the neck ; corona very
wide, with no conspicuous sulcus; antenna three-jointed, wiisetate, decwrved; eyes
large, roundish; teeth two; foot slender, abrupt. Hyaline.

The great width of the expanded corona, and the size of the frontal column and
antenna, are very noticeable in this species; as also the plumpness of the body, and its
sudden attenuation to form the foot, whence its appearance is somewhat like that of
Rotifer macrurus. The spurs are small and the toes short, thick, and truncately conical.
The mastax is set more transversely than usual, so as not to be made out in a longitu-
dinal aspect. Two teeth cross each ramus. In certain lights there seem to be three ;
but a true adjustment with a power of 300 reveals the projecting points, and shows them
to be distinctly two. There is a wide sub-cylindrical stomach with a tubular passage,
followed by a short and somewhat transverse intestine. This latter discharges, through
a narrow but distinct rectum, beneath the second telescopic joint of the foot. Traces of
small globose gastric glands are seen beneath the mastax. A small contractile vesicle
lies in front of the rectum. No other portion of the vascular system has been recorded.
The ovary is large with many clear nuclei. The antenna appears to have only one
terminal seta.

Length. About ,},inch. Habitat. Ponds, ditches, &c.: not uncommon,—P.H.G.]

P. acutEata, Hhrenberg.
(Pl. IX. fig. 5.)

Philodina aculeata « . Ehrenberg, Die Infus. 1838, p. 501, Taf. Ixi. fig. 9.

Dujardin, Hist. Nat. Zooph. 1841, p. 660.

Eckstein, Sieb. wu. Koll. Zeits. Bd. xxxix. 1883, p. 352,
Taf. xxiv. fig. 15.

[SP. CH. Body beset with spines, having no constriction nor swelling at the neck: ;
corona not so wide as the body ; antenna two, long-jointed, mobile ; eyes large, nearly
round ; teeth three ; foot thick, gradual. Dark brown.

This species is easily recognised by the spines which have given it a name; but I
cannot find these appendages nearly so numerous as in Ehrenberg’s figures.! Nor are
they scattered irregularly over the body, but are arranged in rows on the dorsal aspect.
The first row consists of three spines ; the next two rows have two each, and are placed

1 Ehrenberg draws as many as twenty-seven spines, irregularly placed, on the dorsal surface.
Dujardin (apparently following Ehrenberg’s description) says that the body is ‘tout hérissé d’épines
molles.’ Herr Eckstein’s description and figure, however, exactly tally with those of Mr. Gosse, only
the two spines, which in Mr. Gosse’s figures (5b, 5d) of the contracted animal point forwards, are
drawn pointing backwards in Herr Eckstein’s figure of the uncontracted animal. Very likely the
direction of the spines is liable to be reversed by the creature’s contortions.—C. T. H.

102 THE ROTIFERA.

near together about the middle of the back, and the fourth has also two at the bottom
of a strong constriction where the body begins to be attenuated: this pair appears to ter-
minate the body (fig. 5b) when contracted, the posterior segment being bent up and
forward. ‘The upright spines shown in Ehrenberg’s figure I have represented in fig. 5b.
They are situated one on each side, level with the second pair of dorsal spines. Under
pressure, and when seen dorsally, the body assumed the appearance of fig. 5d; by
which the relative positions of the spines is better shown. The frontal column is large
and cylindrical, resembling that of R. macrurus; the tip, which is truncate, but fur-
nished with a little protrusile proboscis, is ciliated, and capable of a rotating vibration.
The wheels are large, and the sulcus at the chin is deep.

The antenna is large and prominent; it is capable of being erected, of projecting
horizontally, or of hanging downward. It consists of two joints, the first tapering to
the articulation, which is telescopic, the second dilating to the tip, which is distinctly
three-lobed. The deep yellowish umber hue of the body, and its close-set longitudinal
furrows, effectually impede the discernment of the internal organs; but I could see that
there is a capacious digestive canal, which attenuates near the fourth row of spines, and
terminates in a cloaca at the endl of the next segment. Near this point is a small con-
tractile vesicle. A large oval transparent ovum was seen in the ventral region of the
trunk. As it showed the jaws perfectly developed, I presume the species to be vivi-
parous. This species very seldom expands its corona while stationary ; it is impatient,
restless, perpetually crawling, or pushing about its closed fore-parts in all directions,
while attached by the foot. Generally the expansion of the corona is instantly followed
by the detachment of the foot, and away the creature shoots head-foremost, and glides
rapidly about the live-box until it is suddenly arrested by coming into contact with some
object.—P.H.G.]

Length. When extended, about ;4, inch. Habitat. Ponds near North London,
(P.H.G.): rare.

P. TUBEROULATA, Gosse, sp. nov.

[SP. CH. Scarcely distinguishable from P. aculeata, but the surface beset with rough
tubercles, instead of spines. Body much fluted longitudinally ; antenna with a small
three-lobed, club-shaped, terminal joint; eyes very small; teeth three, thick; spurs
long, slender, slighly sigmoid, acute. Dark brown.

A species in most particulars resembling P. aculeata, with like club-shaped antenna,
much corrugated and plicated, and of a pronounced wood-brown hue, but having the
recurved spines replaced by rough irregular tubercles, has occurred in water sent by
Mr. Bolton, Birmingham, from Sutton Park. The sediment of this water, of rich golden
brown hue, largely consisting of floccose fecal deposits, as I suppose, full of great
Desmids and other alge, has proved usually rich in Rotifera. Among them, grubbing
sluggishly, was this uncouth Philodina; the whole body clogged with sediment. For
some time I supposed that it might be P. aculeata, the spines modified into tubercles ;
but I have found P. aculeata repeatedly since, with the spines clear and sharp, exactly
as I had drawn them from life thirty-five years ago. And I have also since found
numerous examples of this tubercled form, from other waters, in no respect differing
from the first ; so that I have no doubt of its bemg an undescribed species. It has
very close resemblance to Rotifer tardus, except that the two eyes are not in the frontal
column, but on the level of the mastax. It has also the manners of that species, sloth-
ful, wallowing in the gelatinous floccose, reluctant to move, but ready to rotate.

The frontal column, when extruded to the utmost, is tipped with vibratile cilia,
amidst which a minute proboscis projects, which is double, consisting of two obtuse
blade-like clear lamine, side by side, and slightly divergent.

Length, ;!; inch. Habitat. Sutton Park, Birmingham (P.H.G.): rare.—P.H.G.]

PHILODINAD A. 103

Genus ROTIFER, Schrank.

GEN. CH. Eyes two, within the frontal column.

At first sight it seems strange that so humble a form as that of Rotifer should
have succeeded, not only in attracting universal attention, but also in giving its name to
the whole class of animals to which it belongs. But there are good reasons for its hay-
ing done so. The genus is most widely distributed ;. it has been found in almost every
quarter of the globe: apparently, indeed, wherever it has been looked for. It haunts
alike the damp moss on the Great Sidelhorn at a height of 8,000 feet, and the swamps
and sea-weeds of the Finnish coast; and seems equally at home under the ice in moor-
pools on St. Gotthard, and in the irrigating ditches of the gardens at Cairo. It is, too,
as prolific as it is common, and breeds in captivity as freely as when at liberty. More-
over, the genus Rotifer exhibits the wonder of ciliary rotation in its most effective form ;
for its wreath when in full action looks precisely like a pair of escapement-wheels of a
watch, whirling round at great speed, the cogs looking ‘‘ sometimes like the ancient
battlements of a round tower ; at others ending in sharp points, and forming a kind of
Gothic crown ; now bent all the same way like so many hooks, and now with their ends
clubbed like a number of little mallets.” How a living creature could possess or use
such a contrivance was a hopeless riddle to the early observers; though even some of
the earliest expressed the opinion that the appearance was an optical illusion.

But the marvels of the genus did not end here. It had been asserted by Leuwenhoek
that the creatures might be dried up for months, and yet be restored to life again, This
was enough to fire the dullest imagination; and as also a brisk controversy sprang up
about the accuracy of this assertion, the charms of a dispute were added to those of a
Rotifer, and it was no wonder that the genus secured all its honours; and, like the
bramble, was raised by circumstances to a position which it little deserved.

The whole structure of the genus is so nearly that of Philodina, that it requires but
little notice. The eyes are placed close together within the column, generally near the
extremity, instead of in the neck, as in the case of Philodina. Nerve-threads have been
traced to them and light-refracting bodies seen in them, in the case of Rotifer vulgaris,
by Dr. Zacharias. The only portion of the internal organization that has not been satis-
factorily made out is the reproductive system. Just as in Philodina, no oviduct has as
yet been discovered ; and no one has explained how it is that the living young pass from
their apparently free position in the body-cavity into the cloaca, through which they
have been seen to issue.!

The male, too, is equally unknown; a strange fact, when one considers first that the
structure of the female reproductive organs, so far as it has been studied, is that of a
typical Rotiferon ; and secondly, that thousands of specimens of this genus must have
been watched by many practised observers, during the century and a half which have
elapsed since the animals were discovered.

‘ It is possible that the long thread, which is often seen to pass from the posterior end of the ovary
towards the cloaca, may- really be, not a muscle, as is usually supposed, but the collapsed oviduct ter-
minating in the cloaca, Should this be the case, then the oyum, when it drops from the ovary, does
not fall into the body-cavity, as has been supposed, but simply stretches out over itself that portion of
the delicate investing membrane, which had up to that moment been shrivelled into a mere cord.
As the membrane investing the ovary is of extreme tenuity, it is just possible that it has escaped
observation when extended, not only over the ovary, but even over the developed young. If this expla-
nation proye correct, there is nothing abnormal in the reproductive system of Rotifer. Mr. Gosse quite
coneurs with me in taking this view of the case: a view which had occurred to him before he read
my note.

104 THE ROTIFERA

R. vuuearis, Schrank.

(Pl. X. fig. 2.)

Rotifer vulgaris. < F : Ehrenberg, Die Infus. 1838, p. 484, Taf. Ix. fig. 4.
f 5) 3 . . 3 Pritchard, Infusoria, 1861, p. 703, pl. xxxv. fig. 476-480.
a * : A 6 : Claparéde, Ann. Sci. Nat. Zool. 5 Sér. t. 8, 1867, p. 11,

pl. ili. figs. 6, 7, pl. iv. fig. 1.

FA a 5 : . Cox, Mon. Micr. J. vol. xvii. 1877, p. 301.

3 5 ‘i 5 A ' Eckstein, Sieb. wu. Koll. Zeits. Bd. xxxix. 1883, p. 355,
Taf. xxiii. figs. 6-12.

7 - 6 5 D Q Zacharias, Ann. Nat. Hist. Ser. 5, vol. xv. 1885, p. 125,
pl. v. figs. 1-8.

SP. CH. Body white, smooth, gradually tapering to the foot; spurs and dorsal an-
tenna of moderate length ; eyes round, small ; teeth two.}

The nutritive system of this very common species differs in no way from that of
Philodina. The walls of the stomach are thick and absorbent, and become tinged at
once after the reception of coloured food. The foot gland and nucleated gastric glands
are obvious, and the latter, according to Dr. O. Zacharias (loc. cit.), are three-lobed on the
ventral surface, but confluent on the dorsal. The same observer gives the following account
of the vascular system. The contractile vesicle opens into the dorsally placed cloaca, and
a lateral canal with five vibratile tags can be traced, on each side, down to it from the head.
“Hach tag has the form of a cylindrical beaker seated by its tapering extremity on the
excretory vessel. The beaker is open above, and a broad cilium inserted at its bottom
projects a little beyond the aperture. . . Under a power of 1,500 diameters the oscillation
of the cilia was so violent that the beakers surrounding them were kept in constant
tremulous movement.’ Of the nervous system Dr. Zacharias says: ‘‘ When examined
from the dorsal surface, the anterior portion of the body shows a triangular ganglion
placed immediately in front of the mastax. . . The anterior angle of the triangle emits two
hardly visible branches towards the eye-spots.’’ Dr, Zacharias thinks that nerve-threads
also pass to the extremity of the frontal column and to the antenna ; the former of which
bears two long tactile sete as well as a circlet of small cilia, and the latter a tuft of
sete.

In the same interesting paper, from which I have so freely quoted, there is an
account of an oval parasite, T'rypanococcus rotiferorum, which Prof. von Stein dis-
covered, and which Dr. O. Zacharias was at first inclined to consider as a peculiar kind
of ovum produced by germination from the inner surface of the cuticle. These parasites
were attached to the body-wall at either end of the Rotifer. Hach was an oval hyaline
vesicle, at the free pole of which was a globular finely granulated structure capable of
amceboid movements. Where the parasite was attached was a small aperture in the
body-wall; and near this, inside the parasite, a clear ciliated cavity. From this cavity
an oesophagus is said by Prof. von Stein to go to the opening in the Rotifer’s body-wall.
Dr. O. Zacharias does not seem entirely satisfied that these egg-like structures were
specimens of Trypanococcus rotiferorwm, but as he found_them in abundance it is to be
hoped that before long the matter will be cleared up.

The male of A. vulgaris, as of every other species, is unknown.

Length. When extended, about ;!, inch. Habitat. Most widely distributed in fresh
water: sea-water, Tay Estuary (P.H.G.): very common.

‘ (Since the diagnosis of all the Bdelloids inter se is somewhat indistinct at best, every distinction is
valuable. And it may be added to that of this familiar species (R. vulg.) that it is so strongly, closely,
and eyenly fluted, as to resemble the Callidine; that its length and slenderness, in proportion to its
thickness, are peculiar; and that in crawling it often elongates the foot to such an extent as to recall
(without any exact resemblance) R, macrwrus.—P.H.G.]

PHILODINADAN. 105

R. rarpus, Lhrenberg.
(elexe ties)

Rotifer tardus : : : : Ehrenberg, Die Infus. 1838, p. 490, Taf. lx. fig. 8.
mn + 0 é P : Pritchard, Infusoria, 1861, p. 704.
Pe, - ‘ 4 ; 9 Eckstein, Sieb. w. Koll. Zeits. Bd. xxxix. 1883, p. 358,

pl. xxiii. fig. 13.

[SP. CH. Trunk dull brown, viscous, with foreign bodies attached, corrugated
longitudinally and transversely ; extremities colourless ; dorsal antenna swollen at the
top, large; spurs long ; eyes shaped like long drops, usually broken ; teeth two.

This is a large sluggish Rotifer of clumsy build, fond of groping among floccose
sediment, or of getting within the hollow bracts of a moss and of remaining snuely
ensconced there for some time. It frequently appears contracted, the constrictions
alternating with prominent swellings, like a sack tied in many places, while the body is
fluted almost as regularly as an Ionic column; and its whole surface is covered with a
viscous secretion to which floccose matter, small Diatoms, &e. attach themselves ;
sometimes a long stream of the mucus is dragged behind, with extraneous substances
adhering. The colour appears to be wholly external, and to depend, in some degree,
on the extraneous matters lodged in the viscous coating; for those portions that are
constantly introverted are free from surface-colour, though the viscera have still a slight
yellow tint. The corona is large and powerful, and the frontal column is cylindrical,
truncate with a minute proboscis at the tip, which does not seem sensibly hooked, or
even lengthened, and which projects between and over two small disks each carrying a
wreath of vibrating cilia. Within the column, and at some distanee from its tip, are
the eyes,! which are usually long and drop-like in shape, and often broken ?—one eye often
more than the other. The body tapers gradually to the foot, the last joint of which ends
in the usual three toes, of which the hindmost is the shortest; all these are curved and
claw-like, but truncate. The penultimate spurs are much developed. The dark colour
of the trunk, and its close-set corrugations, nearly destroy its transparency, so as to
make it very difficult to demonstrate the viscera. By pressure, however, on one occasion,
the intestinal canal was forced out, attached to the mastax, the ligaments of the anal
extremity having given way; it appeared then as at fig. 1d; a slender tube, permeating
a thick cellular mass, forming the stomach. The mastax has two distinctly separated
teeth in each ramus. I cannot but think that R. citrinus and Ff. tardus of Ehrenberg
are one and the same species.

Length. When fully extended, up to »!, inch. Habitat. Near London ; Snaresbrook ;
Birmingham ; Woolston ; Dundee (P.H.G.): not uncommon. P.H.G.].

R. MAcROCEROS, Gosse.
(Pl. X. fig. 5.)

Rotifer macroceros . 3 . : Gosse, Ann. Nat. Hist. 2 Ser. vol. viii. 1851, p. 202.
Rotifer Motacilla . 6 : Bartsch, Die Rdderth. b. Tubingen, 1870, p. 48.
9 ” i Rot. Hungaria, 1877, p. 27, iv. Tab. 34 dbra.

(SP. CH. Body ie with eneaninal aie corona large; spurs short, stout ;
dorsal antenna very long and mobile ; eyes small, round ; teeth two.

This form, which I discovered in 1850, and described in ‘‘ Ann. Nat. Hist.”
September 1851, is indubitably a good distinct species. It has occurred repeatedly of
late. The great length of the antenna, being not less than fully one-third of the whole

1 Tf, as I suspect, the Rotifer which Dr. Leydig describes as Rotifer citrinus is really R. tardus,
then each of the eyes of the latter Rotifer eee to Dr. Leydig) has a crystalline light-refracting
body imbedded in the pigment.—P. H. G.

? Herr Hekstein (loc. cit. Taf. xxiii. fig. 12) has noticed a similar anomaly in Rotifer vulgaris, and
Ehrenberg has seen another case in R. macrurus (loc. cit. Taf. Ix. fig. 7,).

106 THE ROTIFERA.

animal when rotating, is very observable, as are also its stiffness, and yet great mobility,
as well as its unusual number of joints. Nor are the actions of this organ less peculiar,
for, in a manner of which I have met with no other example in the class, the animal, in
the act of protruding, jerks the antenna from side to side as if feeling with it, wags it
about rapidly but not vibratingly, and often taps the water, as it were, with it. As soon
as the wheels are quite expanded the antenna becomes still. The organ is very slightly
fusiform, quite transparent, and has either a tube or a band running throughout its
middle, connected apparently with three very short bristles which project from the some-
what enlarged truncate extremity. Perhaps these are very sensitive, and the band may
be a nervous thread which conveys impressions to the brain. Indeed, by careful focus-
ing with a high power, the medial bristle (viewed dorsally) is seen to have a sensible
diameter, and to be the continuation of the permeating band projected. Within the
first jomt, about one-third from the base, the part exterior to it can be retracted.
There is not the least bending at these joints ; the wagging is solely from the base. Two
small pale-crimson eyes are low down in the column, which is normal in form. An
ovate body may sometimes be seen so large as almost wholly to occupy the greater
moiety of the abdominal cavity, quite transparent and colourless, in the midst of which
is a great mastax, not to be distinguished, even in dimensions, from that one which is
proper to the animal, but motionless.! This of course indicates an unborn young, and
proves this species to be viviparous. Alongside of this embryo lies a large sac,
doubtless the stomach, throughout which the action of vibratile cilia lining the interior
is clearly visible. The foot, spurs, and toes are of the usual form. These lowest
joints are usually shortened; the animal habitually sitting, when at rest as well as
when rotating, in a squat position, so that they are almost, if not quite, concealed, the
long antenna always projected. Generally, save when distended either by digesting
food or by an advanced embryo, the whole body is marked with lines, which are longi-
tudinal folds of the skin, not greatly interfering with vision. The corona is unusually
large and the wheels more than usually circular; the latter are separated dorsally by a
wide sulcus, the lower edge of which is a straight horizontal line. The mallei are
evidently two-toothed.—P.H.G.]

Dr. Bartsch found this species in the Weilheimer pool, near Tiibingen, in company
with Floscularia and Melicerta, and published an account of it (Joc. cit.) in 1870. He
describes the great length of the antenna and the creature’s curious actions, ‘‘ stretching
its long antenna far forward and moving it up and down as the water-wagtail does its
tail’’; and, under the impression that it was a new species, named it R. Motacilla. I
have met with this species several times in the clear water of Abbot’s pond near
Clifton. It was always snugly ensconced in a floccose heap on a stem of alga,
or in the axil of a water plant; and its presence was usually first betrayed by its
long antenna, which could be seen waggling about some time before the animal itself
appeared.

Dr. Bartsch in “ Rot. Hungarie ”’ (loc. cit.) figures the gastric glands, stomach, ovary,
and contractile vesicle.

Length, ;1, inch (P.H.G.) Habitat. Near London; Woolston, near Birmingham;
Stormont Loch (P.H.G.) ; Clifton (C.T.H.) : not common.

R. wapticus, Gosse, sp. nov.
(Pl. X. fig. 3.)
(SP. CH. Body clear, brown-stained, not strongly plicate, not enveloped in mucus ;
antenna long, stout, motionless when extended ; corona small.

1 T believe that I have seen the distinction between the stomach and the intestine; and also
another great viscus, which must be the ovary. The cesophagus is wide and short. After some hours,
the mastax of the embryo worked; but not rapidly, and only at intervals,—P.H.G,

PHILODINAD#. 107

This species I have met with on several occasions in the water from Woolston Pond,
though it cannot be considered other than rare. It is one of the larger species, being
equal to R. tardus in size, with which from its form and colour it may readily be
confounded. The colour, however, is a clearer amber, and the comparative absence of
the deep longitudinal folds of the skin gives to this species a bright translucency like
that of stained glass. It readily expands its wheels, which are normal but small. The
antenna, however, is of unusual dimensions both in thickness and length, equalling
R. macroceros in this respect. The organ, however, does not wag to and fro, in the
curious manner characteristic of that species ; nor does the animal squat down on its
hinder parts, concealing its foot. The antenna is fusiform, and carries a distinct joint
at its extremity, which is, I think, retractile ; but not tipped with sete that I could per-
ceive. The thick truncate frontal column bears, near its tip, two large, conspicuous
dark-red eyes, showing the animal to be a true Rotifer. The specific name (from
dmropat, to touch or test) alludes to the presumed function of the prominent antenna.

Length. About inch. Habitat. Woolston Pond (P.H.G.): rare.—P.H.G.]

R. macrurus, Schrank.
(Pl. X. fig. 4.)

Rotifer macrurus ° . 0 Ehrenberg, Die Infus. 1838, p. 490, Taf. Ix. fig. 7.
” ” . 5 c Pritchard, Infusoria, 1861, p. 704.

(SP. CH. Body white, hyaline at the ends, plump, suddenly attenuated to a slender
and very long foot; corona large; spurs small; frontal column long, cylindrical,
truncate ; dorsal antenna of moderate length; eyes usually small and round ; teeth
two.

This is a large and well-marked species, imposing and attractive. Its stout corona,
large wheels, and plump body are much like those of a Philodina; it can be generally
recognized by the sudden break in outline between the trunk and the foot, by the great
length of the latter, and by the long stout column, which stands well up above the
expanded wheels. The spurs are unusually short for so large a Rotifer, being of about
the same length as the three toes. The foot consists apparently of eight joints, almost
all of unusual length. There is a short, but bulging neck. The distinction between
the stomach and intestine is often visible, and the rectum extends through (what
appears to be) the whole basal joint of the foot. There are two oval gastric glands,
as well as a pair of club-shaped glands in the foot. A small contractile vesicle can
be readily seen, and so, with some little difficulty, can the lateral canals and
vibratile tags. Dr. Leydig failed to make out these last, but both Dr. Bartsch (loc.
cit. Tibingen) and myself have seen three tags on each side. The nervous ganglion
has not been noticed. The shape of the eyes appears to be variable. Dr. Leydig
says that he met with some specimens in which the pigment spots were hemispheres
much cut out in front, and in others were lengthened out imto a row of points
lying behind one another. The former had light-refracting bodies seated on them,
which the latter lacked. A pair of muscles, inserted into the neck, pass to the great
constriction behind; another pair, inserted in the shoulders, pass down into the first
joint of the foot ; and a third pair start from near the same point as these last, and pass
to points where the first pair end. Each joint of the foot has at least two longitudinal
muscles on each side, which pass into the joints above them. Under strong pressure
the whole foot is seen to be crossed with transverse muscles of which at least twenty can
be counted. High pressure shows numerous muscles in the trunk also. These are in
the form of broad bands alternating with spaces of equal width. I saw the birth of a
young one twenty-four hours after it had (apparently) escaped from an oval membrane
into the body-cayity. It passed head-first through the cloaca in a few seconds. It was

108 THE ROTIFERA.

compressed during the passage, and the parent's cloaca was but little disturbed. This
young one extended, before its birth, from the base of its parent’s foot to the base of
the column; and, when born, was ;'5 of an inch long, or about two thirds of its parent’s
length.

Length. When extended, about =), inch. Habitat. Widely distributed: common,—
P.H.G.]

Genus ACTINURUS, Hhrenberg.

[GEN. CH. Thewhole animal excessively long and slender ; eyes two, frontal ; teeth
two, converging.

Technically, there is little but its extreme length and tenuity to distinguish this
genus from Rotifer; the only difference that Ehrenberg gives (viz. the number of the
toes) being founded on error, since all the Rotifers have three, and not, as he assigns to
them, two. Yet he has done well to separate the present form. The diminution of
thickness, and the great development of length, impart a peculiar facies, which at
once precludes the possibility of mistaking it for any species of Fotifer, as soon as seen.
Even in contraction the trunk is not sensibly thickened, never swelling in the middle as
in the other genera of the family it does.—P.H.G.]

A. nEprunius, Hhrenberg.
(Pl. X. fig. 6.)
Actinurus Neptunius . ; c Ehrenberg, Die Infus. 1838, p. 496, Taf. Ixi. fig. 1.
: Pritchard, Infusoria, 1861, p. 704, pl. xxxv. figs. 481-4.
Eckstein, Sieb. wu. Koll. Zeits. Bd. xxxix. 1883, p. 359,
Taf. xxiv. fig. 17.

(SP. CH. Frontal column short, carrying the eyes near its base ; corona small ;
trunk long, slender, cylindrical ; foot protrusile to twice the length of the trunk ; spurs
small, two-jointed ; toes very long, recwrued.

From its excessive length and tenuity the appearance of the creature is very remark-
able. It may be likened to a cylindrical tube out of which protrude a great number of
draw tubes from both extremities, principally the posterior one. The head is peculiar,
when viewed laterally ; ovate in form, the frontal column very short, and the eyes being
oval, dark and large, with the antennal tube projecting obliquely backwards, it presents
a ludicrously strong resemblance to the head of a rabbit. The rotatory organs are small
and seldom unfolded ; the eyes of an intense red, almost black. The eight or nine joints
which constitute the foot are of extreme slenderness, and its spurs consist each of two
joints ; the first club-shaped, the second very slender and acute. The three long, slender,
cylindrical, diverging toes, are flexible, and commonly bent outward. Owing to the
slenderness of the body the viscera are greatly elongated. The mastax is at a consider-
able distance from the corona, and is reached by a long buccal funnel. Hach ramus
bears two inwardly-converging teeth. The digestive canal is apparently undivided, and
originates directly from the mastax : with, I think, two small gastric glands. I think I
detected a contractile vesicle. The viscera, however, can be demonstrated with difficulty,
partly owing to the strong longitudinal corrugations in the dorsal region of the trunk, and
partly to the creature’s incessant contractions and elongations. The ovary is obvious,
and the appearance of the eggs suggests that the animal is viviparous. This singular
creature is lively in its motions; and it is a curious sight to see the immense
length of foot suddenly thrust forth from the body, in which it had been completely
hidden, the starting out of the horizontal processes, and the diverging of the long toes,
as these are successively uncovered.

Length. Fully extended, ;!; inch: closed, ;4, inch. Habitat. North London ;
Leamington ; Caversham : rather rare (P.H.G.).—P.H.G.]

” ”

” ”

PHILODINAD Al. 109

Genus CALLIDINA, Ehrenberg.

GEN. CH. Eyes absent.

Although this genus differs technically in so slight a degree from those which we
have considered, yet it can be generally recognized by its slender, pointed shape, its
smaller size, and the abundant corrugations of its skim. Its internal organization, with
the exception of the eyes, is so precisely that of Rotifer, that it requires no special descrip-
tion. One of the species (Mr. Gosse’s C. bihamata) possesses a very obvious pair of
those dorsal hooks which are so characteristic of the nearly related Melicertade, and
which are to be found also in the still humbler and more closely connected genus
Adineta.

C. pvecans, Ehrenberg.

Callidina elegans . a . : Ehrenberg, Die Infus. 1838, p. 482, Taf. Ix. fig. 1.
“A “f f : 6 9 Perty, Zur Kenntniss kleinst. Lebensf. 1852, p. 43.
a s ; 5 a 5 Pritchard, Infusoria, 1861, p. 702, pl. xxxiv. figs. 470-3.

(SP. CH. Body fusiform, abruptly enlarged centrally, strongly fluted, collared ;
frontal column thick, truncate, ciliate, with a decurved proboscis ; jaws with no promi-
nent teeth ; foot thick ; spurs moderate.

This species, the only one of the genus known to Ehrenberg, I find not uncommon
in yarious waters: but it is only by careful observation that it can be distinguished from
its congeners. The corona is scarcely wider than the body, the double disk being very
little more than a full circle, or two circles very slightly separated, when seen quite
vertically. The column is short, unusually thick, with a minute acute proboscis over-
arching the dorsal edge of its tip. The antenna longer than width of corona, slender,
subequal throughout, flexible, truncate, carrying (apparently) a short terminal brush of
fine sete. A swelling collar above the antenna. The trunk, bounded above and below
by a strong transverse fold, is abruptly swollen, impressed with strong longitudinal
plaits, frequently visible as the animal turns. The foot is thick; the penultimate spurs
middling ; the three toes well developed. The outline is very variable. The trunk is
tinged with clear yellow-umber, which is abruptly defined at both ends; the extremities
being colourless, and very hyaline when stretched in extension.

The trophi, when viewed quite dorsally, have much of the form seen in the Rhizota,
as figured (for Limnias) in my mem. “On Mand. Org.” fig. 71: the rami being long
and pointed, and having a projecting handle-like knob. After keen scrutiny, I cannot
discover any teeth crossing them, or anything to break the uniformity. I hence con-
clude that there are only the very close minute lineations, which Ehrenberg describes.
A vanishing shadow of a curved line on each side may represent the mallei, but quite
undefined. The restlessness of the animal precludes fine definition. It is most im-
patient, incessantly moving, not still for an instant. It rarely swims, but perpetually
erawls by alternate elongation and shortening, in a course excessively devious.

Length, 4, to 7;inch. Habitat. Sutton Park Ditch; Woolston Pond: rather
common (P,H.G.).—P.H.G.].

C. BIDENS, Gosse.
(Pl. X. fig. 8.)

Callidina bidens . é ci c Gosse, Ann. Nat. Hist. 2 Ser. vol. viii. 1851, p. 202.

(SP. CH. Surface closely corrugated ; spurs minute, conical, pointed ; teeth two.

I obtained this species at Messrs. Smith and Beck’s in 1849, from a nearly putre-
scent infusion of hay, in which it was swarming almost to the exclusion of everything
else. Its manners differ much from those of other Philodinade. -It is, if I may use

110 THE ROTIFERA.

the term, very wild, shooting about with swiftness in an impatient manner, with a
peculiar mingling of swimming and creeping ; proceeding in this way all about the live-
box by the hour together, so rapidly and irregularly that the motion of the stage can
scarcely keep it in the field. It is much bolder than the other members of the family,
keeping its wheels in rotation all the time it is attached; and though a sudden jar, or
the impact of another animal, will cause it to close them, it is but for an instant. I
have never seen it contract on alarm into a short round bulb; far less remain quiescent
in such a condition for hours, as Rotifer and Philodina do. It is spindle-shaped, the
central region of the body always having an angular prominence ; but this varies its
situation, sometimes the upper part, sometimes the middle, sometimes the posterior of
the abdomen, projecting, according to the position of the viscera at the moment; the
creature thus assumes various candelabra-like forms, as shown in figs. 8, 8a. The head,
when extended, terminates ina thick rounded column which is ciliated ; when the wheels
are expanded, the column appears small, square, and truncate, fits in below the wheels,
and does not project beyond their surface. The foot is moderate in length; the spurs
of the penultimate joint are very minute cones, and the last joint has one small stiff
point behind, and two soft cylindrical protrusile lateral toes, truncate at their extremities.
The whole surface of the body is covered with minute irregular and close-set corruga-
tions. The buccal funnel is very long, and the rami, which are very small, are each
crossed with two teeth. A scarcely appreciable cesophagus leads to an enormous and
very mobile stomach: in one specimen this organ appeared to be composed of a number
of spherical cells; in others of a minutely granulated texture: it ends in a short
rectum.

There are two corrugated glands in the foot, and a contractile vesicle (whose period
is forty seconds) with the usual lateral canals. A long ovary with double rows of rudi-
mentary ova occupies each side of the stomach, and two large eggs are commonly seen,
of a bright pellucid appearance, but sometimes dark and granulate. The whole animal
is crystalline, and usually colourless, but I have seen a specimen in which the wheels
were of a delicate pale citron-colour, and another in which the intestine was of nearly
the same cinnabar hue as in Philodina roseola, though not so brilliant. It is note-
worthy, seeing that the creature is eyeless, that the specimens which I first possessed
had been kept in the dark; expressly because “it was found speedily to die, if kept in
the light.””. With the phial of water I obtained, I impregnated two vessels, one of which
I placed in a window, the other in a dark corner. Five months elapsed, when, on
examination, the species was abundant in the darkened phial: but in that in the window
I could not find a single specimen.

Length. About 4; inch. Habitat. Pools on Hampstead Heath; lake in Kew

5

Gardens (P.H.G.).—P.H.G.]

C. parasitica, Giglioli.
(Pl Xie 795)

Callidina parasitica c 0 " Giglioli, Quart. J. Micr. Sci. N. Ser. vol. iii. 1863,
p. 237, pl. xi.

SP. CH. Spurs stowt, conical, as long as width of the contracted joint ; teeth two.
Parasitic on the limbs of crustacea.

This species was discovered by Mr. H. Giglioli as an epizoic parasite on the thoracic
and abdominal appendages of Gammarus pulex and Asellus vulgaris ; and was figured
and elaborately described by him loc. cit. According to Mr. Giglioli the body is very
transparent and colourless, fusiform in shape, and without the angular prominence at
its central region which is so distinct in C. bidens. The corona consists of two small
circlets of short cilia, and is rarely expanded ; the animal usually contenting itself with
crawling like a leech over its host. here is a distinct alimentary canal surrounded by

PHILODINAD:. 111

a yellowish-green cellular mass, a broad pyriform ciliated stomach, narrowing gradually
to a bent intestine, and again widening into a broad and richly ciliated cloaca. No
salivary or gastric glands have been seen. There is a large irregular contractile vesicle,
with a period of about thirty seconds, and two very small lateral canals; the vibra-
tile tags, however, have not been made out. The dorsal antenna is large, and divided
into three lobes at its tip, but no sete were visible. No eyes have been seen either in
the adult or young. [I found several examples in June 1885, on the thoracic limbs of
Gammarus pulex. To Mr. Giglioli’s interesting details I have little to add. He says
that out of 700 or 800 Gammari, he had not found one free from these Callidine. My
experience is not quite confirmatory of this constancy. Out of four Gammari, I found
Callidine on only one. They adhered to its limbs merely as other Bdelloids do to any
surface. The ‘suckers,’’ mentioned by Mr. Giglioli, are no organs of special function,
connected with parasitism, but are the three truncate toes common to the whole order.

My examples, four in number, crawled off their nurse presently, on the subjection of
the latter to pressure in the live-box, and moved actively about in the free water ; con-
tracting, and elongating, and readily swimming. Their hue was a pale straw-yellow,
becoming clear ochre-yellow in contraction, which deepened to umber in the middle of
the alimentary canal, and in the maturing ovum: but of a glassy translueency. The
pair of spurs at the bottom of the penultimate joint of the telescopic foot, are stout,
thick, long and pointed. It is difficult with creatures so extremely variable in outline
to give any measurements which are not too vague to be distinetive: yet, as compared
with these organs in C. bidens, I may say that in C. parasitica they are as long as the
diameter of the penultimate joint itself, when thickened to its utmost by retraction ;
whereas in C. bidens their length does not equal half the width of the joint in the same
condition. Their bases are separated by a horizontal space equal to their own breadth
(fig. 9d). The joint itself is closely and minutely fluted.— P.H.G.].

Length. Up to =; inch. Habitat. Parasitic on Gammarus pulex and Asellus
vulgaris (Mr. H. Giglioli; P.H.G.).

C. BIHAMATA, Gosse, sp. nov.
(BID Xe ties 7.)

(SP. CH. Frontal column bearing two hooks, mutually crossed.

This species I found in the sediment of a phial of water that had been standing on
my study table for more than a month, originally sent to me by Mr. H. Davis, dipped by
him from a pool near Snaresbrook in June 1885.

It has not any obvious peculiarity to distinguish it from its congeners, except that the
column is terminated by a pair of acute hooks, set on the same plane, and crossing each
other transversely, like the blades of a pair of shears. These at first sight suggested
the C. vaga of the friend to whose kindness I had been indebted for this stranger. A
moment’s observation showed that it was not that species, now elevated by Dr. Hudson
to the rank of a genus, Adineta. Yet the peculiar structure in question may well be
considered as a marked approach to it. Minute hooks, terminating the column, are,
indeed, common to all the species of the Bdelloida, but usually soft, obtuse, decurved,
and single. The whole trunk, somewhat swollen, is strongly scored with longitudinal
folds of the skin ; a dozen or more in number. The double corona was readily expanded,
and the animal glided freely and swiftly through the free water. It is small, as in
Callidina generally: the column with its terminal hooks was projected (or rather not
retracted) during the coronal rotation, The dorsal antenna is placed unusually far
back (see fig. 7a) ; it is small, obtuse, oblique, connected with a dorsal tubercle ; not
seated on it, but, so to speak, leaning on its front slope. It is scarcely in advance of
the mastax, when this is in its normal position. I did not see on it either cilia or set.

Length. Estimated at about 7, inch. Habitat. Pool near Snaresbrook (P.H.G.).—
P.H.G.]

112 THE ROTIFERA.

Family [V. ADINETAD.

Corona a flat, prone surface ; ciliary wreath the furred ventral surface of the
corona ; trophi ramate ; frontal column soldered to dorsal surface, and ending in two
hooks.

The family Adinetad@ has been formed to receive one genus, which itself contains
at present only one species. It has been separated from the Philodinad@ on account of
its lacking the usual corona of two circlets, and of its having in lieu of it a mere furring
of a flattened, ventrally placed, portion of the head, which in some degree resembles
the face of the genus Proales. In other respects the organization is that of the Calli-
dine, except that the frontal column, which is so striking a feature in the other Philo-
dinad@, and which is tossed aside like a hood when the coronal wheels are expanded,
is here soldered as it were to the dorsal surface, and projects slightly beyond it, bearing
two curved hooks.

Genus ADINETA, Hudson.
GEN. CH. Eyes absent.

A. vaca, Davis.
(Pl. X. fig. 10.)
Callidina vaga : ; : . Davis, Mon. Micr. J. vol. ix. 1873, p. 201, pl. xiv.

SP. CH. Body smooth, colowrless, with longitudinal corrugations; spurs short,
finely pointed ; teeth two.

This species was discovered by Mr. H. Davis in 1867, along with abundant speci-
mens of P. voseola, ina parcel of pink dust sent to him by the Rey. Lord §. G. Osborne,
and found in some open stone vases in Lord Osborne’s grounds at Blandford. These
vases, at times, become partly filled with rain, and the wind drives into them dead
leaves and other matters, which by their decomposition seem to afford suitable food.

The front of the head is somewhat like a thumb in outline, and on its dorsal surface
is what appears to be the trace of a column soldered to the head, projecting slightly
beyond it, and bearing two transverse hooks. The corona, though nothing but the flat
ventral surface of the head, yet shows a sort of division into two parts, owing to the
absence of cilia on a broad median line leading to the buccal funnel: the rest of the
surface is densely furred with minute cilia. The base of the corona, just at the animal’s
neck, rises on either side above its general plane, and forms a well-marked ridge. Mr.
Davis says that each ridge is strongly serrated, and draws them with teeth pointing
forwards. I could see no such serrations, though the strong cilia, that here lead to the
entrance of the buccal funnel, frequently produced a fleeting appearance of serration :
but all my specimens were small and young, and possibly the serrations were not yet
developed. The pathway (if it may be so termed), through the coronal cilia, leads
straight to a long buccal funnel imbedded in a thick fleshy mass, and ending at the
mastax, each ramus of which bears two main teeth and a multitude of fine parallel
strie.! When Adineta is feeding, it curves the flat corona so as to bring its two furred
halves opposite to each other, and at the same time draws together the transverse
ridges at its base. In this way a ciliated semi-cylinder is formed as a prolongation of
the buccal funnel, and minute atoms may be seen rapidly streaming down the tract
clear of cilia, into the funnel’s entrance. The stomachs of my specimens were all filled
with clear yellowish particles, but of what substance I could not make out. I could see
no salivary or gastric glands, but the foot-glands were conspicuous. The contractile

' Mr. Davis measured these, and found there were from thirty to forty thousand in the inch; in
my specimens the striw were about fifty thousand to the inch.

ADINETADA. 118

vesicle was also plainly visible: Mr. Davis says that its period is about twenty seconds in
the young, and from two minutes to five minutes in the adult. By compression I obtained
an unusually distinct view of the lateral canals (fig. 10b), which showed clear against the
grey ground of the ovary. Mr. Davis has seen five vibratile tags on each side, but not the
lateral canals ; and I succeeded in finding two pairs of tags attached to the canals : one pair
just below the transverse ridges of the corona’s base, and another mid-way between this
point and the contractile vesicle. There is a dorsal antenna; but no eyes: the nervous
ganglion has not been made out.

A. vaga may be recognised at once by its peculiar movements, which are unlike
those of any other Rotiferon I am acquainted with, and are also extremely embarrassing
to the observer. It fastens itself by its foot, extends its body to its full length, and
then swiftly contracts itself. Nor is this all; for, instantly extending itself again, it
alters its direction, as well as its distance from the surface to which it is attached. In
this way it will work around its toes, as around a pivot, compelling the observer to make
incessant alterations of the stage and focus. In fact very little is to be learned of its
structure, while it is permitted to go free. When imprisoned in a very closely flattened
drop of water, it is a little more manageable, for it ceases then to dart backwards and
forwards; but on the other hand it makes up for this by constantly gliding about at a
very fair pace. It is quite incapable of swimming in the open, and may now and then
be seen rolling ignominiously from the top of the glass cell to the bottom ; but it glides
with ease over the surfaces of stems, plauts, or glass, by the reaction of those sur-
faces on the ciliated head. It is, if possible, a hardier creature even than Philo-
dina roseola ; for Lord Osborne tells me that he has repeatedly found that, in a mixed
gathering of the two, A. vaga will survive successive dryings and moistenings which
have proved fatal to all the former.!

Length. From =); to 3, inch. Habitat. In some stone garden-yases at Bland-
ford (Lord 8. G. Osborne); in a mill-pond at Petit Bot, Guernsey (C.T.H.); frequently
in dried gatherings of Philodina roseola.

1 Mr. Davis’s experiments (loc. cit.) show that this is not always the case.

CISUAVEMM alee WAOUE
PLOIMA

(IL-LORICATA).

Curiosum nobis ingenium Natura dedit, et artis sibi ae pulchritudinis
sue conscia spectatores nos tantis rerum spectaculis genuit; perditura
fructum sui, si tam magna, tam clara, tam subtiliter ducta, tam nitida,
et non uno genere formata solitudini ostenderet.—SENECA.

For Beauty, Good, and Knowledge are three sisters
That doat upon each other, friends to man,
Living together under the same roof,

And never can be sundered without tears.
TENNYSON.

CHAPTER VIII.

Order III. PLOIMA.

Swimming with their ciliary wreath, and (in some cases) creeping with their toes.

It has been already seen! that our typical Rotiferon was drawn from the ranks of
the PLOIMA ; and rightly so, for the number of its genera, the abundance of its species,
the restless energy, perfection of structure, and superior intelligence of its members,
clearly entitle the third order to be considered.the typical one. It is true that Pedalion
makes a still nearer approach to the Arthropoda in its structure than does any species
of the PLOIMA, and must be ranked above them in the scale of the animal kingdom; but
it is almost (if not quite) the only representative of its order, and therefore unfitted to
be taken as a type of the class.

In the Free-Swimmers the mastax reaches its highest development, and is often used
like the mandibles of an insect. Mr. Gosse and I, as well as other observers, have seen
these active creatures seize their prey with their jaws, and watched them nibbling the floe-
cose sediment on the stems of water-plants, or slitting up the cells of algee and the skins of
infusoria in order to extract their contents. Indeed, the snapping of the protruded jaws
among some of the Notommatade is so vigorous that it is difficult to see it and not to
fancy that we hear the snap; and on one occasion, even, the fierce atom has been seen
to give itself a fatal lock-jaw by its outrageous snatch.

In this order, too, as might have been expected from their habits, the nervous system
is conspicuous, the ganglion being large, and the nervous threads from it to the various
organs of sense more easily traced than in the first and second orders. The eyes, too,
have often obvious lenses, and the tactile organs are numerous and well-developed. The
vascular system, whose probable respiratory functions must be of the utmost importance
to these restless animals, is unusually well developed. It spreads a network of coiling
tubes close under the cuticle, and not unfrequently ends in a contractile vesicle so large
as to fill, when distended, an important portion of the body-cavity.

In fact, the whole structure of the order shows its members to be well equipped for
the energetic life which observation proves them to pursue. They haunt the alge on
pond walls, coast along the water-line among decayed leaves and floating débris, dive
down to the bottom to explore the muddy sediment, or boldly put off from shore, and
sail out even into the middle of such a lake as that of Zurich. No doubt the marvellous
corone of the Rhizota and Bdelloida will always continue to attract the expert and
amateur alike ; but to obtain an adequate notion of the structure of the Rotifera, and of
what may fairly be termed their mental capacities, the inquirer must turn to the study
of the PLOIMA,

Sub-Order In-LoRICATA.

Integument flexible, not stiffened to an inclosing shell; foot, when present, almost
invariably furcate, but not transversely wrinkled ; rarely more than feebly telescopic,
and partially retractile.

ED eets

118 THE ROTIFERA.

Family V. MICROCODIDA.

Corona oblique'y transverse, flat, circular ; buccal orifice central ; ciliary wreath
a marginal continuous curve encircling the corona, and two curves of larger cilia, one on
each side of the buccal orifice ; trophi forcipate ; foot stylate.

Genus MICROCODON, Ehrenberg.

GEN. CH. Eye single, centrally placed, just below the ccrona.

M. cuavus, Ehrenberg.
(Pl. XI. fig. 1.)

Microcodon clavus . ‘ Ehrenberg, Die Infus. 1838, p. 395, Taf. xliv. fig. 1.
. Pritchard, Infusoria, 1861, p. 665, pl. xxxil. figs. 371-2.
Grenacher, Sieb. wv. Kill. Zeits. Bd. xix. 1869, p. 487, Taf. xxxvii. fig. 2.

This eurious Rotiferon, for which, though the only species of the genus, it has
been found necessary to make a new family, was discovered by Ehrenberg in 1880. It
has since been described by Dr. Max Perty and Dr. H. Grenacher (loc. cit.), and has
been found in England several times by Dr. Collins, at Sandhurst, and lately by Miss
Davies, at Woolston. It has, however, escaped the notice of the majority of observers
during the last fifty years, m some measure no doubt owing to its small size; for
though its whole length is +3; inch, more than one-half of this is taken up by a long
narrow foot, so that the actual body of the animal does not much exceed 5}, inch.
Ehrenberg placed it in his family Megalotrochea ; but neither in its ciliary wreath, its
trophi, nor its foot, does it resemble the Rhizota. The corona is a flat circular disk, set
obliquely on the trunk, and with its dorsal edge pointing forwards.! A complete ring of
minute cilia edges the disk, and these perform the oftice of driving the food to the buccal —
funnel. The entrance to this latter is near the centre of the corona, a little towards the
ventral surface. It lies between two curves of large unequal cilia, of such lengths and
so arranged that they form on each side an oval border to the buccal orifice. Usually
these large cilia are at rest ; and Microcodon, under the action of the smaller cilia, either
glides along swiftly or oscillates gently to and fro over the same spot, as if it were moored
by a thread from its single toe. It is possible that this curious hovering over one place
may be due to the mutually opposing action of the minute cilia of the two halves of the
corona, but it always gave me the impression that the animal was at these times moored
by a viscous thread to some spot on the glass. Every now and then, whether gliding
along or hovering, the creature darts suddenly forward with the utmost swiftness, accom-
plishing this by vigorous strokes from the two rows of larger cilia. It would seem that
it has unusual control over this apparatus, for Dr. Grenacher has seen, in an injured
specimen, these inner cilia lifted and depressed one by one; and has traced to them
what he supposes to be nerve-threads arising from the depth of the corona. A further
peculiarity noticed by this observer is that the corona remains expanded, no matter how
the animal be treated.

The trophi (fig. 1c) consist mainly of two ribbed rami, attached to a long narrow
plate (the fulerum), which is seen edgewise in the figure. I think, too, that I detected
delicate pointed unci on each side of the incus. The whole are included in a long conical
mastax, closely resembling that of Polyarthra, and pointing downwards towards the

‘ Ehrenberg says that its shape is that of a transverse figure 8; but Dr. Grenacher, Dr. Collins,
Mr. Gosse, and myself all agree that it is circular. Mr. Gosse, however, points out that, when the
corona is inclined to the line of sight, it does look somewhat like that of a Limnias.

MICROCODIDA; ASPLANCHNAD AS. 119

ventral surface. Dr. Grenacher says that there is no separation between the stomach and
intestine, but this Mr. Gosse has distinctly seen. The latter says: ‘‘ When I first detected
the animal, the intestine occupying the gibbous swelling of the hind abdomen was clear,
save for a considerable well-defined mass of orange-red; but, on resuming my observa-
tions on it an hour or so later, the intestine was not distinguishable from the stomach,
the whole being of a deep rich sienna-brown, with oil-globules of various sizes scattered
throughout it.” The ovary appears to be divided into two distinct portions, and a clear
reddish spot, somewhat like an oil-globule, but of unknown function, lies between the
stomach and ovary. A contractile vesicle is conspicuous above the foot, and Dr.
Grenacher notices his haying seen indistinctly the lateral canals, but not any vibratile
tags. There are two spherical gastric glands, and just above these, at the head of the
mastax, is a round nervous ganglion, on which is seated a splendid eye. It is a purple
ball, resting on purple plates curving round the ganglion, so as to give the whole a
curious likeness to a jockey’s cap (fig. 15). Two of these stripes appeared to have been
displaced in my specimen, but I cannot tell if this was an accident or if their position
is normal. I could only make out these details by flooding the animal with transmitted
light. There are a dorsal and two lateral antenne, all mere setigerous warts; and the
foot bears just above the toe on the dorsal side three bristles, which Dr. Grenacher says
are erectile. The same observer has noticed that the longitudinal muscles which move
the foot, and are continued down into it from the body, are all striated. The foot is
divided into three joints, of which the first and last are small, and it ends in a single
toe. It is freely moved from one side to the other, round its basal joint, and is some-
times laid flat to the ventral surface.

The Male.—[A female had been playing in my live-box within an area formed by
bounding filaments of Myriophyllum. Presently I saw a slender worm, about as long
as this charming subject itself, of almost aerial transparency, very slender, darting about
the same limited area. It was a nearly perfect cylinder, but gradually tapering to an
acute extremity, which may possibly have been a minute conical toe. The front, slightly
bent downward, was transversely truncate; its circular margin carrying a wreath of
locomotive cilia, by whose vibrations it shot vigorously and rapidly about. The whole
body was refractive of light, but one vesicle, situate about two-thirds from the front was
more intensely refractive. This I suspect to have been the sperm-sac. I could detect
no other organ or viscus in the animal, but the entire length and breadth was full of
minute granules. My grounds for suggesting that this was the male Microcodon are but
inferential. First, the motions were exactly imitative of those which I had just been
watching in the female—swift glidings hither and thither, occasionally varied with
moments of sudden pausing, and again with still more sudden and invisibly rapid starts
and springs to a distance. Secondly, its appearance at the same time, in the same dip,
and in the same limited area with the female, which itself is a rarely occurring species
with me: and thirdly, the apparent attentions which the supposed male paid to the
female, every now and then coming close to her in his devious travels, though only to
shoot by her. The area was quite open at one end; yet for a long time, and not till
after many sailings to and fro, did he assert his freedom, when she presently followed.
PEG.

Length. From ,}, to ;3,; inch, of which the foot is more than half. Habitat.
Sandhurst (Dr. Collins, P.H.G.); Woolston Pond, Hants (Miss Davies, P.H.G.).

Family VI. ASPLANCHNADA.

Corona swb-conical, with one or two apices ; ciliary wreath single, edging the corona;
intestine ani cloaca absent.

The Asplanchnade, though singularly beautiful Rotifera, are yet of a low type of
structure, for their stomach is a blind sac, and they reject all fecal matter through

120 THE ROTIFERA.

the mouth. The family contains the genera Asplanchna and Sacculus, which, while
separated from all other Rotifera by the absence of intestine and cloaca, differ also from
each other in several important pomts. The incudate trophi of Asplanchna are massive
forceps quite free from an inclosing mastax, and capable in consequence of even plung-
ing down into the cesophagus ; but the forcipate trophi of Sacculus are feeble hooks and
blades, inclosed in a grape-shaped mastax, and admitting of only a slight protrusion
from the mouth. The stomachs also of the two genera are widely different: that of
Asplanchna, a spheroidal bag of moderate dimensions ; that of Sacculus, a large sac with
six great cecal appendages nearly filling up the whole of the body-cavity : and, further,
Sacculus carries its eggs attached by a thread to a hollow of the posterior surface,
while Asplanchna produces its young alive.

Genus ASPLANCHNA, Gosse.

GEN. CH. Corona with two apices; trophi incudate, not inclosed within a mastaz ;
stomach of moderate size, spheroidal. Viviparous.

The various species of this genus differ from each other mainly in the presence or
absence of the foot, in the shape of the trophi, in the number and colour of the eyes, in
the size and arrangement of the vascular system, and in the external shape and appendages
of the male.

It was in this genus that the first male Rotiferon was discovered; and, indeed, the
great size and transparency of the female, and its habit of producing its young alive,
give unusual facilities for the study of the males. Many of the Rotifera deposit their
eggs here and there on the stems and leaves of alge &e., so that it is impossible to
identify the males when hatched; but in the genus Asplanchna the male may be readily
seen alive in its mother’s ovary. It is a creature of the greatest delicacy, like a bubble
of the clearest glass; and yet the various species can be easily distinguished by the
differences of figure. In one the male is a mere reproduction of its parent on a reduced
scale; in another it bears two sleeve-like processes on its sides; in a third, four such
processes ; while one has its ventral surface prolonged into a sheath for the penis.

A. Esprspornit, Hudson.
(Pl. XI. fig. 8.)
Asplanchna Ebbesbornit . 4 Hudson, J. Roy. Mier. Soc. 2 Ser. vol. iii. 1883, p. 621, pls. ix. x.

Female with one dorsal, one ventral, and two lateral humps; eye single ; rami with
singly pointed ends, not serrated ; contractile vesicle expaniding to more than half the
body-cavity ; vibratile tags often forty on each side, and arranged in straight lines ;
ovary horseshoe-shaped ; male with two additional, lateral, humps, below the neck.

This fine and rare Rotiferon was discovered by Mrs. Tupper Carey in 1880, in a
duck-pond in the vicarage of Ebbesborne Wake ; and, strange to say, this, at present, is
its only known habitat. It differs from all other species of the genus in its outline,
which is not bell-shaped, and in its possession of four sleeve-like prolongations of the
cuticle ; one on the dorsal surface, one at the hind end of the ventral, and one on each
side of the body below the head. All these appendages are empty of organs, and some-
what flaccid when the animal is swimming quietly ; but, when it draws in its head, they
are driven out stiffly from the general surface. Fine muscular threads tie their ex-
tremities to various parts of the body, and serve to shorten the processes when the head
is again protruded : the two side appendages have their tips connected by a fibre passing
straight through the body from the one to the other. The head is conical with two
apices ; and in the hollow between them, a little towards the ventral surface, lies the
buccal orifice, with two small style-bearing prominences on either side of it. The
ciliary wreath is a simple ring of cilia surrounding the coronal cone, and bent down

ASPLANCHNADAL. 121

inwards at the ventral surface, to the buecal orifice. This latter opens directly on the
jaws, which are two stout hooked rami with their fulerum plate imbedded in a horse-
shoe-shaped cushion : doubtless, as Mr. Gosse suggests, the third lobe of the mastax:
there are no other lobes, so the jaws are practically free. The muscular bands which
open and shut these formidable nippers are shown in fig. 8e, and can be seen with ease.
Immediately below the horseshoe-shaped ring, and partly embraced by it, is a chamber
or pharynx formed by a delicate membrane strained over four curved rods, which hang
downwards, and are joimed together at the bottom by cross pieces. This curious con-
trivance resembles somewhat in shape the silk well of a lady’s work-table. By suddenly
pulling the four rods apart at the top, the animal causes a partial vacuum, and any prey
near the buccal orifice is instantly engulfed. I have seen this happen often, even to
Rotifera of considerable size; for A. Hbbesbornu, like all the Asplanchne, is an indis-
criminate feeder, and will swallow even such awkward mouthfuls as Triarthra longiseta
and Brachionus Bakeri; the latter of which I have seen with its posterior spines
actually piercing the stomach and body walls of the Asplanchna, while the former I saw
head-downwards in the esophagus, with its long propellers stretching right up almost to
the buccal orifice. From the pharynx, on its ventral side, stretches a very long trans-
parent and extensile esophagus, down which run ribbon-like muscular threads. Not
unfrequently it is loaded with food, so that the creature seems then to have a stomach
of twice the usual size. The gastric glands (figs. 8c, 3d) have each a large duet lead-
ing to the stomach, and the cells imbedded in them lie together in clusters of four and
five. The spherical stomach has thick cellular walls with a clear round nucleus in each
cell; it is often divided for a time into two unequal portions by a deep muscular con-
striction, as in fig. 8a. There is not a trace of intestine or cloaca: the hind end of the
stomach is merely attached to the body by two fine threads. The feeal matter is
rejected through the mouth; it is slowly driven up by successive contractious of the
stomach and esophagus, till it reaches the pharynx, where it is grasped by the jaws and
tossed out through the buccal orifice. There is a rectangular nervous ganglion just
under the corona, touching the buccal orifice on its dorsal side, and earrying a crimson
eye. A nerye-thread passes from each of the four corners to one of the antenne. Two
of these latter are on the dorsal side of the body about half-way down, and two others
are on the coronal apices. There is yet another pair on the corona just above the
buccal orifice, and to these branch nerves are sent from those of the second pair. The
ovary is horseshoe-shaped, flattened at the ends, and studded with germs which are
often clusters of cells (fig. 81). The ova are always developed at the hind-surface of
the middle of the ovary : and, when they attain some size, they drop off into the ovisac,
a funnel-shaped pocket with its broad base attached to the contractile vesicle. The ovi-
sac ends in an oviduct, which opens on the ventral surface in a transverse slit. Ocea-
sionally I have met with specimens that had as many as three or four ephippial. eggs
in the ovisae at once; but generally there is only one maturing ovum, or a young
animal lying across the parent with its head presented to the opening of the oviduct.
The birth of the young is almost instantaneous; and I have seen it expelled with such
force that its stomach was driven right through its mouth, so that it was born with its
ciliary wreath half-way down its body. The ephippial eggs! are circular, corrugated,
and often tinged yellow ; as is sometimes the ovary itself.

The male (fig. 87) is rather more than half the size of the female, and bears two small
additional appendages below the neck. As usual, the entire digestive tract is absent.
There are, however, some rounded masses adhering to the dorsal surface, just below the
hump. Possibly these may be a kind of stored-up material to compensate for the male’s
inability to take nourishment.

The sperm-sac with its enclosed spermatozoa, and the penis, are shown in fig. 3).
The penis is a tube with delicate longitudinal furrows sheathed in soft granular masses,

1 Two ephippial eggs are shown in fig. 3.

122 THE ROTIFERA.

and having a ciliated opening, It can be drawn back by two pairs of muscles attached to
the dorsal surface. Short muscular threads help to draw and direct it forward ; but its
vigorous outward movement is mainly due to the compression of the body-fluids by
transverse muscles. The spermatozoa can be distinctly seen in motion in the sperm-sac,
and they are of the two forms drawn in fig. 3k. The vascular system (fig. 3/) is alike
in both sexes, but is much better seen in the male. The floceulent ribbons which
support the lateral canals are unusually large and long, and are looped up here and
there by threads, and also tied in the same way to the body-walls. They appear, them-
selves, to be tubes of a loose granular stuff, with clear cells (fig. 8g) imbedded in their
walls. Possibly it is through these cells that the perivisceral fluid finds its way into
the tubes and thence into the lateral canals. These latter are much smaller tubes, con-
nected with the first, but meandering along their edge ; and they have attached to them an
amazing number of vibratile tags; often more than forty on either side. The contractile
vesicle, to which the flocewlent ribbons and lateral canals are obyiously attached, swells
out in the female, at times, so as to occupy nearly two-thirds of the body. In the male
it is smaller, but in both sexes it is covered with a fine muscular network, which is con-
stantly compressing it into ever-varying and graceful shapes. The muscular system is
best seen in the male, owing to the absence of digestive organs, but is so plainly shown
in the drawings that it requires no further explanation.

Length. Nearly 1; inch. Habitat. Ebbesborne Wake, Wiltshire (Mrs. Tupper
Carey): very rare.

A. BRiGHTWELLU, Gosse.
(PI Xai fig: 1)

A dicecious rotifer allied to the genus Notommata . 2 Brightwell, Ann. Nat. Hist. 2 Ser. vol. ii.
; 1848, p. 153, pl. vi.
An infusory animateule allied to the genus Notommata . Dalrymple, Phil. Trans. 1849, p. 331, pls.
XXXiii. XXXiy.
Asplanchna Brightwellit and A. Bowesti . 5 : - Gosse, Ann. Nat. Hist. 2 Ser. vol. vi.
1850, p. 28.
Ascomorpha Anglica 9 5 6 C 5 0 : Perty, Zur Kenntniss kleinst. Lebensf.

1852, p. 39.

SP. CH. Female without humps; eye single; rami with doubly pointed ends, not
serrated; contractile vesicle expanding to about one-fourth of body-cavity ; vibratile
tags on each side varying from about ten to twenty, and arranged in a straight line; ovary
horseshoe-shaped ; male without humps.

Mr. Brightwell discovered this species in a small pond immediately without the city
of Norwich in 1841. Both sexes were in abundance, so that he was able not only to
make out the structure of the male, but also to witness several acts of copulation ; thus,
for the first time, establishing beyond all question the dicecious character of at least one
species of the Rotifera. The female differs from that of A. Hbbesbornii in the following
points. It is bell-shaped, possessing none of those humps which are so striking a feature
in the former species. The jaws (fig. 1) differ slightly in their proportions and shape,
and Mr. Dalrymple (loc. cit.) detected on either side of the stout rami delicate curved
rods, which no doubt are the unci. The gastric glands are kidney-shaped, the contrac-
tile vesicle somewhat smaller. The ephippial egg of this species is also circular, but it
has on its outer covering a beautiful pattern of concentric circles of overlapping scales.
The male (fig. 1c) is also humpless, but it is a little squarer in outline behind than the
female, from the ventral surface having been produced into a sheath for the penis.!

Length. Female, ;'; inch; male, j inch. Habitat. Ponds and ditches in many
parts of England: not uncommon.

‘In 1874 I found an Asplanchna apparently not distinguishable from A. Brightwellii, and whose
male (Mon. Micr. J. pl. xci.) had only two lateral humps. Mr. T. Bolton has lately found both sexes

Sof

near Birmingham. I have named it provisionally A. intermedia. = <97 4-72

Le U ot

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CLK

ASPLANCHNADZE. 123

A. PRIODONTA, Gosse.
(Pl. XII. fig. 2.)
Asplinchna priodonta' . 4 Gosse, Ann. Nat. Hist. 2 Ser. vol. vi. 1850, p. 18, pls. i. ii.

SP. CH. Female without hwmps; eyes three; rami broadening to the free ends,
their inner edges serrated; contractile vesicle about equal to the two gastric glands to-
gether; vibratile tags fowr on each side, attached to a single coil of tubes; ovary
roundish; male without humps.

Mr. Dalrymple’s exhaustive memoir on A. Brightwellii was followed soon afterwards
by a similar paper of Mr. Gosse’s on his new species, A. priodonta, in which its structure
is described with the greatest minuteness and care. A. priodonta was discovered by
Mr. Gosse in the Serpentine, in Hyde Park, in 1850. It is much smaller than 4. Bright-
wellii, its outline more oval, its head more conical. The jaws are broader: and instead
of a projecting tooth on the inner side, they have this edge minutely serrated, with the
tip forming two curved long teeth (figs. 2f, 2g). Hach carries a spine proceeding from
its back and curving round nearly parallel to its extremity. The gastric glands are
situated on the cesophagus itself, a little above the stomach, not on it. But the chief
differences lie in the vascular and reproductive systems. The contractile vesicle, when
full, is globular and small, being scarcely, if at all, bigger than the two gastric glands
together. The flocculent ribbons that support the lateral canals have their middle parts
wrinkled into a large coil of four or five pairs of doublings, and on this coil are placed
four vibratile tags ; so that there are only eight tags in all. The ovary is roundish and
very small; it is shown in fig. 2a with its germs, and the ovisac wrinkled up close to it.
In fig. 2 it is behind and above the ovisac, which contains a developing ovum with
salmon-coloured oil-globules in it. There are three crimson eyes (fig. 2b), one under
the centre of the corona and one on each side of it; each resting on a nervous ganglion.

The male (fig. 2c) differs hardly at all in its internal structure from that of A. Hbbes-
bornit, though very different in shape. Its sperm-sac is supported by a strip of tissue
that hangs from the head, and resembles in shape and position the alimentary canal of
the female. It is, however, imperforate and structureless, and seems to have no other
office than to support the sperm-sac and penis. The nervous ganglion (fig. 2d) is un-
usually conspicuous. Two of its four diverging threads pass downwards to the dorso-
lateral rocket-headed antenne (figs. 2c, 2e), and two pass upwards to similar antennae
on the two apices of the corona.

By slightly compressing a male, I put beyond question the fact that the contractile
vesicle empties itself owtward through the cloaca; for under slight pressure the vesicle
contracted slowly, by stages as it were, collapsing partially im separate efforts instead of
closing at once. As it did so, I distinctly saw, at each effort, the gradual passage of a
plug of fluid down the cloaca, dilating its walls as it went.

Length. Female, #, inch; male, 7; inch. Habitat. Kensington Gardens, Serpentine
(P.H.G.); ponds and ditches round Clifton and Birmingham (C.T.H.; T.B.): not un-
common.

' Ehrenberg’s Notommata syrinx is wonderfully like A. priodonta, but is said to have a cloaca, and
a minute foot and toes. His N. myrmeleo is unknown in England, but Leydig has made it clear
(Ueb. d. Bau. d. Réderth. p. 20, Taf. iv. fig. 36) that in this instance Ehrenberg has made a mistake,
and that the Rotiferon has not got the cloaca which Hhrenberg describes. It is therefore an Asplanchna
with a foot; one much resembling that of Notops clavulata. Its jaws, ovary, vascular system and eye
resemble those of A. Brightwellii.

Leydig (loc. cit.) has described another Notommata, N. Sieboldii, which is a true Asplanchna. The
fcmale closely resembles A. Brightwellii; but the male, which is conical in shape, has four humps,
two lateral ones and two on the neck, just like those of the male of A, Ebbesbornii.

124 THE ROTIFERA.

Genus SACCULUS, Gosse.

GEN. CH. Corona with one apex; trophi inclosed in a mastax, virgate, with unequal
mallet, very evanescent; alimentary canal very large, having eight ceca; eggs attached
after deposition.

S. vinipis, Gosse.
(Pl. XI. fig. 2.)

Sacculus viridis. ; ‘ Gosse, Ann. Nat. Hist. 2 Ser. vol. viii. 1851, p. 198.
Ascomorpha helvetica. . Perty, Zur Kenntniss kleinst. Lebensf. 1852, p. 39.
Ascomorpha germanica (2). Leydig, Ueb. d. Bau. d. Raderth. 1854, p. 44, Taf. iil. fig. 34.
Sacculus viridis. 9 6 Gosse, Phil. Trans. 1857, p. 320, pl. xv. figs. 24-26.
Ascomorpha saltans (?) . 5 Bartsch, Rot. Hungaria, 1877, appendix, Tab. ii. fig. 17.

This beautiful ‘* little green sac’’ was first discovered by Mr. Gosse, in the summer
of 1850, in a small pool on Hampstead Heath, and was described by lim in the ‘‘Annals
of Natural History” in 1851. It haunts the bottoms of small pools on heaths and in
plantations, and I have occasionally found it roaming over the vegetable sediment at the
shallow ends of cattle-ponds. It is not a common creature, and it is an extremely
difficult one to study, for its skin is thick and rough, and its huge stomach hides almost
all the other organs.

The ciliary wreath is a simple ring of cilia with three or four large styles set in it at
intervals. Just below the wreath, on the dorsal side, is a comparatively clear space of
external surface (figs. 2, 2b), which is shagreened, as it were, with diamond-shaped
clusters of granules. Through this can be seen the nervous ganglion, bearing a crimson
eye, and (I think) the front portions of two spherical gastric glands. The ovoid mastax
can be readily seen in the side view; it contains delicate triangular rami on a long
slender fulcrum and two rod-like mallei, which Mr. Gosse thinks are of unequal length.
The shape of the stomach is very unusual. Seen dorsally it appears to consist of two
cylindrical sacs, one on each side, tapering in front, curved towards each other behind,
and connected by a broad cross sac, so as to have a rude resemblance to a letter H. A
lateral view shows four short, equal sacs hanging down from the long side sacs ; two on
each, The whole of this strange stomach is stuffed full of beautiful green oval bodies,
which are probably the zoospores of alge. At each of the four junctions of the short
sacs with the long ones there is a dark-brown spot, which seems to consist of decomposing
food. No observer has seen any fecal discharge, or detected a cloaca; and although I
made several specimens fast for some hours in clear water I failed to obtain one with a
comparatively empty stomach. The ovary les between the four short cecal prolongations
of the storaach, and the contractile vesicle lies deep down below the connecting cross
sac. The animal carries its eggs attached to its hind extremity ; bearing sometimes one
or two female eggs, or occasionally a whole cluster of small male eggs.

[From one of the eggs, which, before maturity, are much clouded and spotted with
granules and globules, a young one was produced in my live-box, which was, I doubt
not, a male (fig. 2c). I could not detect any eye (though this organ is conspicuous in
the parent) nor any internal organisation ; nothing but a confused assemblage of granules
and globules; even the ordinary opaque masses were not present. The form somewhat
resembled that of an amphora with a short wide neck ; the frontal cilia were very large,
but the motion was not rapid, nor was the animal wild, as male Rotifera usually are.—
PFE Ge (Phil irans.12 loc aces)

Length. Female, ;1, inch; male, ;4, inch. Habitat. Hampstead Heath (P.H.G.) ;
Clifton (C.T.H.).

Family VII. SYNCHATADA.
Corona a transverse spheroidal segment, sometimes nuuch flattened, with styligerous

prominences ; ciliary wreath a single interrupted or continuous marginal curve, encircling
the corona; mastax very large, pear-shaped; trophi forcipate; foot minute, furcate.

SYNCHATAD A. 125

Genus SYNCHATA.

GEN. CH. Form uswally that of a long cone whose apex is the foot; front furnished
with two ciliated auricles ; ciliary wreath of interrupted curves ; foot minute, furcate.

Though this genus consists of only a few species yet it is alike interesting in its
structure and its habits. The various species differ from each other chiefly in the shape
of the body and of the coronal head, as well as in the number and position of the tactile
organs. There is, too, at least one species which is marine, and which has been said by
its presence to render sea-water luminous.

In all the species the striking characters are the swift and varied motions, the ciliated
auricles, the huge mastax, and the long delicate w@sophagus closely resembling that of
Asplanchna.

8. pectinata, Hhrenberg.
r (Pl. XIII. fig. 8.)

Syncheta pectinata ; * Ehrenberg, Die Infus. 1838, p. 437, Taf. liii. fig. 4.

Syncheta mordax . ° ° Gosse, Ann. Nat. Hist. 2 Ser. vol. viii. 1851, p. 200.

Syncheta pectinata 5 5 Leydig, Ueb. d. Bau d. Rdderth. 1854, p. 41.

Syncheta mordax . 5 5 Pritchard, Infusoria, 1861, p. 686, pl. xxxili. fig, 422.

” ” oD - Hudson, Mon. Micr. J. vol. iv. 1870, p. 26, pl. lvi.

SP. CH. Body a swollen cone; auricles very long, pointed, usually pendent ;
coronal head very large and conver; two club-shaped prominences in front, each
crowned with a wide brush of sete ; four styles, the outer pair sometimes compound.

This is the finest and most vigorous of the Synchete. No one can watch it
swimming in ample space, without marvelling at the energy of this living speck, and
admiring the grace and ease of its varied motions. No swift is more untiring in its
flight. Now it sweeps along in spiral turns from the surface to the bottom, and now it
darts through the green branches of the water crow-foot to hang motionless over a leaf
like a hovering fly in summer; motionless, and yet with its front all ringed with the
halo of its furiously lashing cilia. The auricles, which seem mere rudimentary stumps,
are really most effective organs of locomotion. They are tongue-shaped fleshy pro-
tuberances, edged with powerful cilia; and, as they can be set by special muscles at
various angles to the body, the creature can dart, wheel, and stop, with the greatest ease.
The trunk, seen ventrally, appears to be a cone tapering to a small foot divided into two
minute toes, but the side view shows the dorsal surface rising behind the head into a
distinct hump. ‘The coronal head is nearly half a spheroid. Round its base on the
dorsal side are four semicircular curves of small cilia, and two similar curves edge cup-
like protuberances on the ventral side. These cups can be lowered or raised a little at
will, and their contour altered so as to enable their frimge of cilia to sweep the food
effectively between the two into the buccal orifice. This les near the top of the coronal
head towards the ventral side. It can be seen only by looking directly at the top of the
head ; no dorsal or side view will show it, and, unluckily, these are the only views that a
compressorium will yield. I have, however, on one or two occasions found a Syncheta,
left in an open cell, swimming feebly in an upright position just before it died; and I
have thus caught sight of the buccal orifice. It is an oval opening between the ventral
cups, and overshadowed by two projections each bearing a fan of styles. As the atoms
of food are swept towards the orifice, the fans are bent over it, and the styles lash the
water to drive downwards any escaping prey. Many Rotifera have a similar contrivance,
notably the Brachioni, whose coronal styles form quite a dome over the buccal orifice.
The corona bears also four tactile organs, two towards the dorsal, and two towards the
ventral side ; and each consisting of one or more styles issuing from a small prominence,
and set in a short cylinder. ‘To the end of the cylinder a muscle is attached, so that by
this means the styles it carries can be withdrawn nearly below the surface. There is
yet another organ of touch. At the summit of the dorsal hump meet two rocket-
headed antenne, each bearing a tuft of sete ; and the two tufts issue together from the

126 THE ROTIFERA.

same opening. A nerve-thread passes from each rocket-head to a nervous ganglion in
the head, on which is seated a bluish-purple eye-spot ! bearing a refractive body, shaped
somewhat like a truncated cone.

The great mastax is a pear-shaped body placed so close to the buccal orifice that
there is no room for a buccal funnel. The forcipate trophi are driven snapping through
the buccal orifice by the great striated muscles shown in fig. 3. A V-shaped one
embraces the end of the fulcrum, and one on each side acts on each malleus. The
esophagus closely resembles that of Asplanchna, and like that is often used as a supple-
mentary stomach. Indeed, I have seen it so full that, for a moment, I did not recognize
Syncheta, and thought that I had found a new Rotiferon. The gastric glands are
small and round; the foot glands obvious. The stomach is usually yellow, but sometimes
brown; more rarely, pink. It is round, with thick walls formed of very large cells.
Sometimes these are studded all over with oil-globules, as in fig. 83. The lateral canals
with their vibratile tags can be plainly seen in the lower half of the trunk, but do
not appear to run up to the head in the usual fashion. There is a small round contrac-
tile vesicle just above the foot. The longitudinal and transverse muscles, as well as
those that work the auricles, can be seen in fig. 8, and need no further description.

The male is as yet unknown.

Length, 1; inch. Habitat. Clear ponds and reservoirs: common.

SyncnmTa Banrioa, Ehrenberg.
(Pl. XII. fig. 1.)

Syncheta baltica . 0 5 ¢ . : Ehrenberg, Die Infus. p. 437, Taf. liii. fig, 5.
Gosse, Tenby, p. 274, pl. xiv.

iSP sy CEH: Body ote 2C, Toe conical behind, or bell-shaped: gibbous
dorsally; rotatory clusters four; styles four; crest single, sessile. Luminous. Marine.

The form is usually that of a bell, or a long cone, viewed dorsally ; but much arched,
viewed laterally. The auricular lobes are very small : two equidistant sete radiate from
the occiput. There are two ciliated eminences besides the auricles, and a medial crest,
smooth-edged. he front is rather wider than the body, whose hinder part tapers to a
well-jointed foot, and two very minute conical toes. Conspicuous pear-shaped mucus-
glands from these run up through the foot.

A large red eye is seated at the end of a cylindrical brain-sac: below which is the
vast mastax of normal structure. We see, now and then, a momentary snatching
action with this organ, of which I have not been able to define the actual seat. A
sudden trembling also occasionally passes through the whole fore parts. A long
cesophagus leads to a small sacculate yellow stomach, on which are seated ample gastric
glands. A small intestine opens into the cloaca, above which projects a wart, which is
a true tail. A band-like ovary, of horseshoe form, the ends forward, lies in the lower
belly ; and behind this a small contractile bladder, whose period is 24 times a minute.
The muscular system is very distinct: a cord from the frontal region is inserted in the
skin of the back, thrown into sigmoid curves during contraction; other cords proceed
from the hind-head to various points near the middle of the trunk ; one (pair ?) proceeds
from the mid-back to the side ; five or six bands run transversely across the back. There
are, moreover, long diagonal bands down the sides.

The brilliant translucency of this animal makes it a very charming object, particu-
larly when well illuminated on a dark ground, when the eye shines out like a ruby, and
the whole body resembles a sparkling diamond. Its movements are vivacious and
elegant. It shoots rapidly along, or circles about in giddy dance, in company with its
fellows, sometimes near the surface, sometimes just over the bottom of its prison. Occa-
sionally the foot and tiny toes are drawn up into the body, and then suddenly thrust
down, and bent up from side to side, as a dog wags his tail. Sometimes the two ear-

' Crimson by lamp-light and dark-field illumination.

SYNCHATADA. 127

lobes are brought forward, and then spasmodically spring back to their ordinary position,
when the creature shoots forward with redoubled energy. All its actions display vigour
and precision ; and convey the impression of intelligence and will.

The most interesting fact connected with its history is that it seems to be one of the
sources of the phosphoric light which often pervades the waves of the sea. In July,
1854, at Tenby, I saw the water within the harbour splendidly luminous. No trace of
light, indeed, appeared on the smooth surface, but when this was agitated it blazed.
The finest effect was produced by dashing a large stone down from the quay : every spray
that splashed up was luminous ; and thus a momentary star of many irregular rays of
light was made, some of the lines reaching to fifteen or twenty feet. At the same
moment a great circular wave was raised, which took the appearance of a bank, or
annular agger, most intensely lustrous, but so transient that the progression of the wave
could not be traced; the light sank into darkness in an instant. The Bristol steamer
was just leaving the wharf, and an impatient stroke or two from her paddles illuminated
the dark water under her quarter, and the lowest step of the quay stairs was every
instant covered with sparks, like diamond dust, by the tiny wavelets that washed over it.
On examination, I found specimens of S. Baltica in it; associated, however, with other
animaleules, both larger and smaller, which were indubitably luminous, as Noctiluca
and Ceratium.

I first met with this species in July, 1850, in water from the mouth of the Naze, in
Essex. Mr. Hood has lately found it in the estuary of the Tay, in Scotland, with many
other marine Rotifera; and has communicated living specimens to me, one of which has
contributed to the present description.—P.H.G,]

Length, ,1, to +3, inch; width, z}5 to 44; inch. Habitat. Sea-water; coasts of
England, Wales, and Scotland (P.H.G.; J.H.).

S. optonea ?, Hhrenberg.
(Pl. XIII. fig. 4.)

Syncheta oblonga (?) . : 6 5 Ehrenberg, Die Infus. 1838, p. 438, Taf. lili. fig. 6.

[SP. CH. Body ovate or pyriform; head very large; auricles wide; ‘ rotatory
clusters siz; styles fowr; crest single, sessile’’; toe single, minute, without foot. Lacus-
trine.

A species which I met with in the Watering Pond on Hampstead Heath in 1850, I
concluded to be S. oblonga of Ehrenberg, though I could not identify all the characters.
But a single specimen occurred, and I have never seen it since, till in November 1885,
in a tube dipped from Keeper’s Pond, Birmingham, and sent to me by Mr. Bolton, I met
with a second example, recently dead, but in fair preservation.

The front has two minute ridges, each with an edging of short comb-like spines ;
outside these are the two knobbed antenne, on which I did not detect any brushes of
divergent set. A good deal lower, on the slope of the auricle, on one side, was a long
stiff bristle, doubtless one of a pair. The auricles are very large, and each is pervaded
by a chain of globose bodies, possibly ganglia, which, having passed around the swollen
extremity, turns back at least as far as the base of the bristle. A vast mastax exists,
whose chief visible feature is a stout incus, whose wide rami appear as diverging lines.
A very long, delicate, corrugated esophagus leads to a small, globose, sacculate stomach
(which recalls the structure common in the Asplanchne@) filled with green food; thence
a thick, much-wrinkled intestine passes straight to the extremity, where is a very minute,
conical toe, which I could not by any effort divide. A glandular thread runs from the
tip to a minute globose vacuole (?) at its base. Three great ova, colourless but turbid,
were in the body-cavity, from the appearance of which I should conjecture the animal to be
viviparous. Various muscles and nervous (?) threads are shown in the figure.—P.H.G.]

Length, ,!, inch; greatest width, ;4) inch. Habitat. Hampstead; Birmingham
(P.H.G): rare.

128 THE ROTIFERA.,

S. TREMULA.
(Pl. XIII. fig. 2.)

Syncheta tremula . : ‘ Ehrenberg, Die Infus. 1838, p. 438, Taf. lili. fig. 7.
Leydig, Ueb. d. Bau d. Réderth. 1854, p. 41.
Pritchard, Infusoria, 1861, p. 686.

SP. CH. Body a slender cone ; coronal head nearly truncate ; auricles scarcely pro-
tuberant ; sete four ; no club-shaped prominences ; a sudden diminution in girth below
the cloaca.

S. tremula is rather smaller than S. peclinata, and its habits are different. It loves to
twirl round its own longer axis at the end of a thread stretching from its toes; and, so
twisting, to drift lazily along with the current which bears the object to which it is
attached. Its coronal head is almost flat, and the side auricles are nearly in the same
plane with it. This makes the animal strikingly unlike S. pectinata in outline. It has
no crests on its corona; only four long curyed styles, similar to those of S. pectinata. Its
stomach is generally full of a rich brown food, and I have sometimes captured specimens
with the esophagus at the same time stuffed with some pinkish substance. Its eye is an
intensely dark-red, and Mr. Gosse has detected a refractive body imbedded in the pig-
ment.! There is a rocket-shaped antenna (fig. 2b) on each side of the trunk just above
the foot: organs that 1 have failed to detect in S. pectinata. In all other respects the
structure of the two species is almost identical.

{In one of the shallow evaporating tanks in my orchid house, I found (at the end of
May) this pretty species swarming. It plays, by myriads, just above the dull-green
floccose sediment that settles on the bottom. I learn, from this colony, a habit which I
think has not been recognised as proper to this genus—viz. that, like the Brachioni and
Anure@, and one or two other genera, Syncheta retains its egg after discharge, attached
to its own body, just behind the foot. The egg, which I saw, was nearly globular, of a
pale yellow hue, granular by the process of segmentation.— P.H.G.]

I found the male (fig. 2c) in the winter of 1870. It is much smaller than the female,
narrower for its length, but otherwise much like her in shape, and with the same four
styles on the coronal head. I distinctly noticed in it the entire absence of the nutritive
system ; but its irrepressible energy prevented me from obtaining more than a fleeting
view of the sperm-sac and penis.

Length, ;}, inch. Habitat. Clear ponds: common.

1 (On the occipital aspect of the brain-mass is seated an eye-spot, always conspicuous both from its
great size and from its intense colour, a red so deep as to be practically black. Its outline varies
much; but normally it is a hemisphere, or rounded cone: often it seems homogeneous, but occasionally
we see that it is composed of a multitude of pigment cells agglomerated together and inclosed within
a transparent capsule, whose walls I have frequently detected of a thickness greater than that of one
of the pigment cells. But more than this: I haye seen, so often as to have no doubt of its presence,
an ovate transparent cell, let-in, as it were, into the coloured body of the eye, the dark pigment rising
on each side so as to embrace the base of it. I venture to think this a crystalline lens.—P.H.G.]

Microcodon clavus

”

= 93

or

”

Saceulus viridis

”

oy

ss

Asplanchna Eibbesbor nil

”

s

”

”

”

PLATE XI.

ventral view
side view .
eye, pigment- plete; nervous ganglion
trophi . c
dorsal view .
ventral view

side view. : 5
male .

dorsal view

side view . 5

head; ventral view

cesophagus, stomach, negate Glande and dusts
top of gastric gland, and duct. 5
trophi, with extensor and retractor muscles
lateral canal and vibratile tags; male -

bend in lateral canal, with imbedded glands (?)

central portion of ovary; two ova ferming
male; side view . : , . 4 5

male; penis, sperm-sac, and contractile vesicle .

spermatozoa 5 0 o
rocket-headed, lateral aienos .

| after Dr. Grenacher

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Hanhart amp.

MICROCODON; SACCULUS; ASPLANCHNA .

\ ad viv: del

to 2b, 3. C-T-Hudson)
2c. P-HGosse >)

Sig
9

Figs 2

2.S.VIRIDIS. 3.A7EBBESBORNII .

1.M.CLAVUS.

©, eo

OR

AS SS)
2 S

~

PLATE XII.

Asplanchna Brightwellir . ventral view . : : : : : ras
“ We . sideview . : : c 5 iG

7 5 trophi . : . 5 fafres My. a: Dalegetpiel

“s Ge . male; side view F , G

7 es penis and sperm-sac. (efter Mr. J. Dalrymple)
Asplanchna priodonta . dorsal view . ; 7 , ; : : 5 Gi
7 € : . side view . : : ‘ : : é 2 1G

6 n : . head, from above . : : E ; 3 a 1G

7 Ay ; . male; side view . j ‘ F é > isl

» male; brain, eye, nerve- diveade Z 5 > Jal

» : . male; dorsal antenna . : . 4 : 5 lal

trophi open . 9 5 7 : ; oe Gr

» trophi closed, from Eber : : 6 : 5 GS

trophi closed, side view E : : : 5 (Gi

deals

dur PyUEY

“VINOGOLUd V'2 SITIEMIHOIME VT
“VNHINV TIdSV.

‘BP ATA PE

seein 1eG=9%

assonHd “WIZ

‘

qz-2 A ehiz

1. Syncheta Baltica

2. Syncheeta tremula

”

”

3. Syncheta pectinata.

la. Rs
2a. “7
20. .
2c ”
2d. ”
3a. a
3b. 7

Sc. a .
4. Syncheta oblonga .

Gor or
Sas

”

Polyarthra platyptera

Cc. » ”
5d. .S »
Be. rs ”
of. ” ”

5g. ” ”

5h. A 7 :
6. Triarthra longiseta .
ba. 5 5
6b. - : A
6e. ” ”
6d. + ay
be. ” ”
6f. ” ” .
7. Triarthra breviseta:.
Ta. 5 3S r

8. Triarthra mystacina
9. Pteroessa surda

9a. >

9b.

10a. ,,

”

”

»” ”
10. Pedetes saltator

.

PLATE XIII.

dorsal view

front view

dorsal view

side view 5 3 .
hind extremity, with antenne
male

mastax .

dorsal view.

front view : 3 F
lateral canal and vibratile tags
dorsal antennie

dorsal view

dorsal view

side view 0 5

the same, with male eggs
mastax and cesophagus

plume 5
the same ; the tip enlarged
mastax ; side view .
mastax ; ventral view
males.

side view "i

gastric gland

eye and pigment

striated muscle 6
extremities of spine

side antenna .

ephippial egg

side view .

dorsal view 2
obliquely ventral view
empty lorica; side view .
the same; dorsal view (?)
the same; ventral view (?)
dorsal view

side view

QRPRHHtttttannageae

RQRAQ|AR

of

vine ‘WOIVLIVS GAd Ol “VCENS Id'6 “VNIOVISAW I'S
“VILASIATUA LL VLASIONOTL'9 VAAIdAlVIddS ‘VONOTSO'S% ‘ VIVNILOAd'S'€ VINNAAL'S' 2 VOILTVE'ST
-SALACUd VSSHOUNL VWHLUVIUL *VUHLUVATOd *VIAHINAS

5 eas f @ssorn Ty; aSes or
BP'AIAPE fuosoripEy “Jong BG's meme og Hz Shy.

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la.

1b.

Hydatina senta

PLATE XIV.

dorsal view ;

ventral view (young eed
side view ° 3 -

ideal section of head

hind extremity, showing miuacles
trophi

dead specimen, Nena mineeles
antenna :

internal parasites. 5

one of the same under “Sos
globular body from a parasite
female with internal fungus
male; dorsal view . : ‘
ventral view

side view

mastax .

proboscis, with eyes, eaneuant ais nerve sihveadk é

muscles

jooigon id ov coigs3ii ashes iio) osigco dl aolcoigaeijueicell seigo eo

of “YAMIN 2 VINIS HI

"SHONIHW ‘VNILVCAH
duit qaeyuUeH [Op 'AtA pe UOSPNF 19

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a amay ©

q

l.

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; |
ym |

ea

: “ :

1. Notops Brachionus

la. =F 6)
1b. 7 7
le. mh ct
1d. ” ”

2. Notops hyptopus
Qa. FA 7
Ones "

2c.

3. Notops clavulatus
3a.

PLATE XV.

dorsal view

side view . 5

male; side view 5 :
sete above the buccal funnel
sete on a frontal prominence
dorsal view

side view . : . c 6

the same, showing vascular system .
mastax

ventral view

side view

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0628